;;; figl -*- mode: scheme; coding: utf-8 -*- ;;; Copyright (C) 2013 Andy Wingo ;;; ;;; Figl is free software: you can redistribute it and/or modify it ;;; under the terms of the GNU Lesser General Public License as ;;; published by the Free Software Foundation, either version 3 of the ;;; License, or (at your option) any later version. ;;; ;;; Figl is distributed in the hope that it will be useful, but WITHOUT ;;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY ;;; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General ;;; Public License for more details. ;;; ;;; You should have received a copy of the GNU Lesser General Public ;;; License along with this program. If not, see ;;; . ;;; ;;; Derived from upstream OpenGL documentation. ;;; ;;; Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed ;;; under the SGI Free Software B License. For details, see ;;; http://oss.sgi.com/projects/FreeB/ (http://oss.sgi.com/projects/FreeB/). ;;; ;;; Copyright (C) 2003-2005 3Dlabs Inc. Ltd. This material may be ;;; distributed subject to the terms and conditions set forth in the Open ;;; Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/ ;;; (http://opencontent.org/openpub/). ;;; ;;; Copyright (C) 2005 Addison-Wesley. This material may be distributed ;;; subject to the terms and conditions set forth in the Open Publication ;;; License, v 1.0, 8 June 1999. http://opencontent.org/openpub/ ;;; (http://opencontent.org/openpub/). ;;; ;;; Copyright (C) 2006 Khronos Group. This material may be distributed ;;; subject to the terms and conditions set forth in the Open Publication ;;; License, v 1.0, 8 June 1999. http://opencontent.org/openpub/ ;;; (http://opencontent.org/openpub/). ;;; ;;; Automatically generated; you probably don't want to edit this. To ;;; update, run "make update" in the top-level build tree. ;;; (define-module (figl gl low-level) #:use-module (figl gl runtime) #:use-module (figl gl types) #:export (glAccum glActiveTexture glAlphaFunc glAreTexturesResident glArrayElement glAttachShader glBeginQuery glEndQuery glBegin glEnd glBindAttribLocation glBindBuffer glBindTexture glBitmap glBlendColor glBlendEquationSeparate glBlendEquation glBlendFuncSeparate glBlendFunc glBufferData glBufferSubData glCallLists glCallList glClearAccum glClearColor glClearDepth glClearIndex glClearStencil glClear glClientActiveTexture glClipPlane glColorMask glColorMaterial glColorPointer glColorSubTable glColorTableParameterfv glColorTableParameteriv glColorTable glColor3i glColor3f glColor3ui glColor4i glColor4f glColor4ui glCompileShader glCompressedTexImage1D glCompressedTexImage2D glCompressedTexImage3D glCompressedTexSubImage1D glCompressedTexSubImage2D glCompressedTexSubImage3D glConvolutionFilter1D glConvolutionFilter2D glConvolutionParameterf glConvolutionParameteri glCopyColorSubTable glCopyColorTable glCopyConvolutionFilter1D glCopyConvolutionFilter2D glCopyPixels glCopyTexImage1D glCopyTexImage2D glCopyTexSubImage1D glCopyTexSubImage2D glCopyTexSubImage3D glCreateProgram glCreateShader glCullFace glDeleteBuffers glDeleteLists glDeleteProgram glDeleteQueries glDeleteShader glDeleteTextures glDepthFunc glDepthMask glDepthRange glDetachShader glDrawArrays glDrawBuffers glDrawBuffer glDrawElements glDrawPixels glDrawRangeElements glEdgeFlagPointer glEdgeFlag glEnableClientState glDisableClientState glEnableVertexAttribArray glDisableVertexAttribArray glEnable glDisable glEvalCoord1f glEvalCoord2f glEvalMesh1 glEvalMesh2 glEvalPoint1 glEvalPoint2 glFeedbackBuffer glFinish glFlush glFogCoordPointer glFogCoordf glFogf glFogi glFrontFace glFrustum glGenBuffers glGenLists glGenQueries glGenTextures glGetActiveAttrib glGetActiveUniform glGetAttachedShaders glGetAttribLocation glGetBufferParameteriv glGetBufferPointerv glGetBufferSubData glGetClipPlane glGetColorTableParameterfv glGetColorTableParameteriv glGetColorTable glGetCompressedTexImage glGetConvolutionFilter glGetConvolutionParameterfv glGetConvolutionParameteriv glGetError glGetHistogramParameterfv glGetHistogramParameteriv glGetHistogram glGetLightfv glGetLightiv glGetMapfv glGetMapiv glGetMaterialfv glGetMaterialiv glGetMinmaxParameterfv glGetMinmaxParameteriv glGetMinmax glGetPixelMapfv glGetPixelMapuiv glGetPointerv glGetPolygonStipple glGetProgramInfoLog glGetProgramiv glGetQueryiv glGetQueryObjectiv glGetQueryObjectuiv glGetSeparableFilter glGetShaderInfoLog glGetShaderSource glGetShaderiv glGetString glGetTexEnvfv glGetTexEnviv glGetTexGenfv glGetTexGeniv glGetTexImage glGetTexLevelParameterfv glGetTexLevelParameteriv glGetTexParameterfv glGetTexParameteriv glGetUniformLocation glGetUniformfv glGetUniformiv glGetVertexAttribPointerv glGetVertexAttribfv glGetVertexAttribiv glGetBooleanv glGetDoublev glGetFloatv glGetIntegerv glHint glHistogram glIndexMask glIndexPointer glIndexi glIndexf glIndexub glInitNames glInterleavedArrays glIsBuffer glIsEnabled glIsList glIsProgram glIsQuery glIsShader glIsTexture glLightModelf glLightModeli glLightf glLighti glLineStipple glLineWidth glLinkProgram glListBase glLoadIdentity glLoadMatrixf glLoadName glLoadTransposeMatrixf glLogicOp glMap1f glMap2f glMapBuffer glUnmapBuffer glMapGrid1f glMapGrid2f glMaterialf glMateriali glMatrixMode glMinmax glMultiDrawArrays glMultiDrawElements glMultiTexCoord1i glMultiTexCoord1f glMultiTexCoord2i glMultiTexCoord2f glMultiTexCoord3i glMultiTexCoord3f glMultiTexCoord4i glMultiTexCoord4f glMultMatrixf glMultTransposeMatrixf glNewList glEndList glNormalPointer glNormal3f glNormal3i glOrtho glPassThrough glPixelMapfv glPixelMapuiv glPixelStoref glPixelStorei glPixelTransferf glPixelTransferi glPixelZoom glPointParameterf glPointParameteri glPointSize glPolygonMode glPolygonOffset glPolygonStipple glPrioritizeTextures glPushAttrib glPopAttrib glPushClientAttrib glPopClientAttrib glPushMatrix glPopMatrix glPushName glPopName glRasterPos2i glRasterPos2f glRasterPos3i glRasterPos3f glRasterPos4i glRasterPos4f glReadBuffer glReadPixels glRectf glRecti glRenderMode glResetHistogram glResetMinmax glRotatef glSampleCoverage glScalef glScissor glSecondaryColorPointer glSecondaryColor3i glSecondaryColor3f glSecondaryColor3ui glSelectBuffer glSeparableFilter2D glShadeModel glShaderSource glStencilFuncSeparate glStencilFunc glStencilMaskSeparate glStencilMask glStencilOpSeparate glStencilOp glTexCoordPointer glTexCoord1i glTexCoord1f glTexCoord2i glTexCoord2f glTexCoord3i glTexCoord3f glTexCoord4i glTexCoord4f glTexEnvf glTexEnvi glTexGeni glTexGenf glTexImage1D glTexImage2D glTexImage3D glTexParameterf glTexParameteri glTexSubImage1D glTexSubImage2D glTexSubImage3D glTranslatef glUniform1f glUniform2f glUniform3f glUniform4f glUniform1i glUniform2i glUniform3i glUniform4i glUniformMatrix2fv glUniformMatrix3fv glUniformMatrix4fv glUniformMatrix2x3fv glUniformMatrix3x2fv glUniformMatrix2x4fv glUniformMatrix4x2fv glUniformMatrix3x4fv glUniformMatrix4x3fv glUseProgram glValidateProgram glVertexAttribPointer glVertexAttrib1f glVertexAttrib1s glVertexAttrib2f glVertexAttrib2s glVertexAttrib3f glVertexAttrib3s glVertexAttrib4f glVertexAttrib4s glVertexAttrib4Nub glVertexAttrib4iv glVertexAttrib4uiv glVertexAttrib4Niv glVertexAttrib4Nuiv glVertexPointer glVertex2i glVertex2f glVertex3i glVertex3f glVertex4i glVertex4f glViewport glWindowPos2i glWindowPos2f glWindowPos3i glWindowPos3f)) (define-gl-procedures ((glAccum (op GLenum) (value GLfloat) -> void)) "Operate on the accumulation buffer. OP Specifies the accumulation buffer operation. Symbolic constants `GL_ACCUM', `GL_LOAD', `GL_ADD', `GL_MULT', and `GL_RETURN' are accepted. VALUE Specifies a floating-point value used in the accumulation buffer operation. OP determines how VALUE is used. The accumulation buffer is an extended-range color buffer. Images are not rendered into it. Rather, images rendered into one of the color buffers are added to the contents of the accumulation buffer after rendering. Effects such as antialiasing (of points, lines, and polygons), motion blur, and depth of field can be created by accumulating images generated with different transformation matrices. Each pixel in the accumulation buffer consists of red, green, blue, and alpha values. The number of bits per component in the accumulation buffer depends on the implementation. You can examine this number by calling `glGetIntegerv' four times, with arguments `GL_ACCUM_RED_BITS', `GL_ACCUM_GREEN_BITS', `GL_ACCUM_BLUE_BITS', and `GL_ACCUM_ALPHA_BITS'. Regardless of the number of bits per component, the range of values stored by each component is [-1,1] . The accumulation buffer pixels are mapped one-to-one with frame buffer pixels. `glAccum' operates on the accumulation buffer. The first argument, OP, is a symbolic constant that selects an accumulation buffer operation. The second argument, VALUE, is a floating-point value to be used in that operation. Five operations are specified: `GL_ACCUM', `GL_LOAD', `GL_ADD', `GL_MULT', and `GL_RETURN'. All accumulation buffer operations are limited to the area of the current scissor box and applied identically to the red, green, blue, and alpha components of each pixel. If a `glAccum' operation results in a value outside the range [-1,1] , the contents of an accumulation buffer pixel component are undefined. The operations are as follows: `GL_ACCUM' Obtains R, G, B, and A values from the buffer currently selected for reading (see `glReadBuffer'). Each component value is divided by 2^N-1 , where N is the number of bits allocated to each color component in the currently selected buffer. The result is a floating-point value in the range [0,1] , which is multiplied by VALUE and added to the corresponding pixel component in the accumulation buffer, thereby updating the accumulation buffer. `GL_LOAD' Similar to `GL_ACCUM', except that the current value in the accumulation buffer is not used in the calculation of the new value. That is, the R, G, B, and A values from the currently selected buffer are divided by 2^N-1 , multiplied by VALUE, and then stored in the corresponding accumulation buffer cell, overwriting the current value. `GL_ADD' Adds VALUE to each R, G, B, and A in the accumulation buffer. `GL_MULT' Multiplies each R, G, B, and A in the accumulation buffer by VALUE and returns the scaled component to its corresponding accumulation buffer location. `GL_RETURN' Transfers accumulation buffer values to the color buffer or buffers currently selected for writing. Each R, G, B, and A component is multiplied by VALUE, then multiplied by 2^N-1 , clamped to the range [0,2^N-1] , and stored in the corresponding display buffer cell. The only fragment operations that are applied to this transfer are pixel ownership, scissor, dithering, and color writemasks. To clear the accumulation buffer, call `glClearAccum' with R, G, B, and A values to set it to, then call `glClear' with the accumulation buffer enabled. `GL_INVALID_ENUM' is generated if OP is not an accepted value. `GL_INVALID_OPERATION' is generated if there is no accumulation buffer. `GL_INVALID_OPERATION' is generated if `glAccum' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glActiveTexture (texture GLenum) -> void)) "Select active texture unit. TEXTURE Specifies which texture unit to make active. The number of texture units is implementation dependent, but must be at least two. TEXTURE must be one of `GL_TEXTURE' I , where i ranges from 0 to the larger of (`GL_MAX_TEXTURE_COORDS' - 1) and (`GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS' - 1). The initial value is `GL_TEXTURE0'. `glActiveTexture' selects which texture unit subsequent texture state calls will affect. The number of texture units an implementation supports is implementation dependent, but must be at least 2. Vertex arrays are client-side GL resources, which are selected by the `glClientActiveTexture' routine. `GL_INVALID_ENUM' is generated if TEXTURE is not one of `GL_TEXTURE'I , where i ranges from 0 to the larger of (`GL_MAX_TEXTURE_COORDS' - 1) and (`GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS' - 1).") (define-gl-procedures ((glAlphaFunc (func GLenum) (ref GLclampf) -> void)) "Specify the alpha test function. FUNC Specifies the alpha comparison function. Symbolic constants `GL_NEVER', `GL_LESS', `GL_EQUAL', `GL_LEQUAL', `GL_GREATER', `GL_NOTEQUAL', `GL_GEQUAL', and `GL_ALWAYS' are accepted. The initial value is `GL_ALWAYS'. REF Specifies the reference value that incoming alpha values are compared to. This value is clamped to the range [0,1] , where 0 represents the lowest possible alpha value and 1 the highest possible value. The initial reference value is 0. The alpha test discards fragments depending on the outcome of a comparison between an incoming fragment's alpha value and a constant reference value. `glAlphaFunc' specifies the reference value and the comparison function. The comparison is performed only if alpha testing is enabled. By default, it is not enabled. (See `glEnable' and `glDisable' of `GL_ALPHA_TEST'.) FUNC and REF specify the conditions under which the pixel is drawn. The incoming alpha value is compared to REF using the function specified by FUNC. If the value passes the comparison, the incoming fragment is drawn if it also passes subsequent stencil and depth buffer tests. If the value fails the comparison, no change is made to the frame buffer at that pixel location. The comparison functions are as follows: `GL_NEVER' Never passes. `GL_LESS' Passes if the incoming alpha value is less than the reference value. `GL_EQUAL' Passes if the incoming alpha value is equal to the reference value. `GL_LEQUAL' Passes if the incoming alpha value is less than or equal to the reference value. `GL_GREATER' Passes if the incoming alpha value is greater than the reference value. `GL_NOTEQUAL' Passes if the incoming alpha value is not equal to the reference value. `GL_GEQUAL' Passes if the incoming alpha value is greater than or equal to the reference value. `GL_ALWAYS' Always passes (initial value). `glAlphaFunc' operates on all pixel write operations, including those resulting from the scan conversion of points, lines, polygons, and bitmaps, and from pixel draw and copy operations. `glAlphaFunc' does not affect screen clear operations. `GL_INVALID_ENUM' is generated if FUNC is not an accepted value. `GL_INVALID_OPERATION' is generated if `glAlphaFunc' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glAreTexturesResident (n GLsizei) (textures const-GLuint-*) (residences GLboolean-*) -> GLboolean)) "Determine if textures are loaded in texture memory. N Specifies the number of textures to be queried. TEXTURES Specifies an array containing the names of the textures to be queried. RESIDENCES Specifies an array in which the texture residence status is returned. The residence status of a texture named by an element of TEXTURES is returned in the corresponding element of RESIDENCES. GL establishes a ``working set'' of textures that are resident in texture memory. These textures can be bound to a texture target much more efficiently than textures that are not resident. `glAreTexturesResident' queries the texture residence status of the N textures named by the elements of TEXTURES. If all the named textures are resident, `glAreTexturesResident' returns `GL_TRUE', and the contents of RESIDENCES are undisturbed. If not all the named textures are resident, `glAreTexturesResident' returns `GL_FALSE', and detailed status is returned in the N elements of RESIDENCES. If an element of RESIDENCES is `GL_TRUE', then the texture named by the corresponding element of TEXTURES is resident. The residence status of a single bound texture may also be queried by calling `glGetTexParameter' with the TARGET argument set to the target to which the texture is bound, and the PNAME argument set to `GL_TEXTURE_RESIDENT'. This is the only way that the residence status of a default texture can be queried. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_VALUE' is generated if any element in TEXTURES is 0 or does not name a texture. In that case, the function returns `GL_FALSE' and the contents of RESIDENCES is indeterminate. `GL_INVALID_OPERATION' is generated if `glAreTexturesResident' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glArrayElement (i GLint) -> void)) "Render a vertex using the specified vertex array element. I Specifies an index into the enabled vertex data arrays. `glArrayElement' commands are used within `glBegin'/`glEnd' pairs to specify vertex and attribute data for point, line, and polygon primitives. If `GL_VERTEX_ARRAY' is enabled when `glArrayElement' is called, a single vertex is drawn, using vertex and attribute data taken from location I of the enabled arrays. If `GL_VERTEX_ARRAY' is not enabled, no drawing occurs but the attributes corresponding to the enabled arrays are modified. Use `glArrayElement' to construct primitives by indexing vertex data, rather than by streaming through arrays of data in first-to-last order. Because each call specifies only a single vertex, it is possible to explicitly specify per-primitive attributes such as a single normal for each triangle. Changes made to array data between the execution of `glBegin' and the corresponding execution of `glEnd' may affect calls to `glArrayElement' that are made within the same `glBegin'/`glEnd' period in nonsequential ways. That is, a call to `glArrayElement' that precedes a change to array data may access the changed data, and a call that follows a change to array data may access original data. `GL_INVALID_VALUE' may be generated if I is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped.") (define-gl-procedures ((glAttachShader (program GLuint) (shader GLuint) -> void)) "Attaches a shader object to a program object. PROGRAM Specifies the program object to which a shader object will be attached. SHADER Specifies the shader object that is to be attached. In order to create an executable, there must be a way to specify the list of things that will be linked together. Program objects provide this mechanism. Shaders that are to be linked together in a program object must first be attached to that program object. `glAttachShader' attaches the shader object specified by SHADER to the program object specified by PROGRAM. This indicates that SHADER will be included in link operations that will be performed on PROGRAM. All operations that can be performed on a shader object are valid whether or not the shader object is attached to a program object. It is permissible to attach a shader object to a program object before source code has been loaded into the shader object or before the shader object has been compiled. It is permissible to attach multiple shader objects of the same type because each may contain a portion of the complete shader. It is also permissible to attach a shader object to more than one program object. If a shader object is deleted while it is attached to a program object, it will be flagged for deletion, and deletion will not occur until `glDetachShader' is called to detach it from all program objects to which it is attached. `GL_INVALID_VALUE' is generated if either PROGRAM or SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_OPERATION' is generated if SHADER is already attached to PROGRAM. `GL_INVALID_OPERATION' is generated if `glAttachShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBeginQuery (target GLenum) (id GLuint) -> void) (glEndQuery (target GLenum) -> void)) "Delimit the boundaries of a query object. TARGET Specifies the target type of query object established between `glBeginQuery' and the subsequent `glEndQuery'. The symbolic constant must be `GL_SAMPLES_PASSED'. ID Specifies the name of a query object. `glBeginQuery' and `glEndQuery' delimit the boundaries of a query object. If a query object with name ID does not yet exist it is created. When `glBeginQuery' is executed, the query object's samples-passed counter is reset to 0. Subsequent rendering will increment the counter once for every sample that passes the depth test. When `glEndQuery' is executed, the samples-passed counter is assigned to the query object's result value. This value can be queried by calling `glGetQueryObject' with PNAME`GL_QUERY_RESULT'. Querying the `GL_QUERY_RESULT' implicitly flushes the GL pipeline until the rendering delimited by the query object has completed and the result is available. `GL_QUERY_RESULT_AVAILABLE' can be queried to determine if the result is immediately available or if the rendering is not yet complete. `GL_INVALID_ENUM' is generated if TARGET is not `GL_SAMPLES_PASSED'. `GL_INVALID_OPERATION' is generated if `glBeginQuery' is executed while a query object of the same TARGET is already active. `GL_INVALID_OPERATION' is generated if `glEndQuery' is executed when a query object of the same TARGET is not active. `GL_INVALID_OPERATION' is generated if ID is 0. `GL_INVALID_OPERATION' is generated if ID is the name of an already active query object. `GL_INVALID_OPERATION' is generated if `glBeginQuery' or `glEndQuery' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBegin (mode GLenum) -> void) (glEnd -> void)) "Delimit the vertices of a primitive or a group of like primitives. MODE Specifies the primitive or primitives that will be created from vertices presented between `glBegin' and the subsequent `glEnd'. Ten symbolic constants are accepted: `GL_POINTS', `GL_LINES', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_TRIANGLES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_QUADS', `GL_QUAD_STRIP', and `GL_POLYGON'. `glBegin' and `glEnd' delimit the vertices that define a primitive or a group of like primitives. `glBegin' accepts a single argument that specifies in which of ten ways the vertices are interpreted. Taking N as an integer count starting at one, and N as the total number of vertices specified, the interpretations are as follows: `GL_POINTS' Treats each vertex as a single point. Vertex N defines point N . N points are drawn. `GL_LINES' Treats each pair of vertices as an independent line segment. Vertices 2\u2062N-1 and 2\u2062N define line N . N/2 lines are drawn. `GL_LINE_STRIP' Draws a connected group of line segments from the first vertex to the last. Vertices N and N+1 define line N . N-1 lines are drawn. `GL_LINE_LOOP' Draws a connected group of line segments from the first vertex to the last, then back to the first. Vertices N and N+1 define line N . The last line, however, is defined by vertices N and 1 . N lines are drawn. `GL_TRIANGLES' Treats each triplet of vertices as an independent triangle. Vertices 3\u2062N-2 , 3\u2062N-1 , and 3\u2062N define triangle N . N/3 triangles are drawn. `GL_TRIANGLE_STRIP' Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. For odd N , vertices N , N+1 , and N+2 define triangle N . For even N , vertices N+1 , N , and N+2 define triangle N . N-2 triangles are drawn. `GL_TRIANGLE_FAN' Draws a connected group of triangles. One triangle is defined for each vertex presented after the first two vertices. Vertices 1 , N+1 , and N+2 define triangle N . N-2 triangles are drawn. `GL_QUADS' Treats each group of four vertices as an independent quadrilateral. Vertices 4\u2062N-3 , 4\u2062N-2 , 4\u2062N-1 , and 4\u2062N define quadrilateral N . N/4 quadrilaterals are drawn. `GL_QUAD_STRIP' Draws a connected group of quadrilaterals. One quadrilateral is defined for each pair of vertices presented after the first pair. Vertices 2\u2062N-1 , 2\u2062N , 2\u2062N+2 , and 2\u2062N+1 define quadrilateral N . N/2-1 quadrilaterals are drawn. Note that the order in which vertices are used to construct a quadrilateral from strip data is different from that used with independent data. `GL_POLYGON' Draws a single, convex polygon. Vertices 1 through N define this polygon. Only a subset of GL commands can be used between `glBegin' and `glEnd'. The commands are `glVertex', `glColor', `glSecondaryColor', `glIndex', `glNormal', `glFogCoord', `glTexCoord', `glMultiTexCoord', `glVertexAttrib', `glEvalCoord', `glEvalPoint', `glArrayElement', `glMaterial', and `glEdgeFlag'. Also, it is acceptable to use `glCallList' or `glCallLists' to execute display lists that include only the preceding commands. If any other GL command is executed between `glBegin' and `glEnd', the error flag is set and the command is ignored. Regardless of the value chosen for MODE, there is no limit to the number of vertices that can be defined between `glBegin' and `glEnd'. Lines, triangles, quadrilaterals, and polygons that are incompletely specified are not drawn. Incomplete specification results when either too few vertices are provided to specify even a single primitive or when an incorrect multiple of vertices is specified. The incomplete primitive is ignored; the rest are drawn. The minimum specification of vertices for each primitive is as follows: 1 for a point, 2 for a line, 3 for a triangle, 4 for a quadrilateral, and 3 for a polygon. Modes that require a certain multiple of vertices are `GL_LINES' (2), `GL_TRIANGLES' (3), `GL_QUADS' (4), and `GL_QUAD_STRIP' (2). `GL_INVALID_ENUM' is generated if MODE is set to an unaccepted value. `GL_INVALID_OPERATION' is generated if `glBegin' is executed between a `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if `glEnd' is executed without being preceded by a `glBegin'. `GL_INVALID_OPERATION' is generated if a command other than `glVertex', `glColor', `glSecondaryColor', `glIndex', `glNormal', `glFogCoord', `glTexCoord', `glMultiTexCoord', `glVertexAttrib', `glEvalCoord', `glEvalPoint', `glArrayElement', `glMaterial', `glEdgeFlag', `glCallList', or `glCallLists' is executed between the execution of `glBegin' and the corresponding execution `glEnd'. Execution of `glEnableClientState', `glDisableClientState', `glEdgeFlagPointer', `glFogCoordPointer', `glTexCoordPointer', `glColorPointer', `glSecondaryColorPointer', `glIndexPointer', `glNormalPointer', `glVertexPointer', `glVertexAttribPointer', `glInterleavedArrays', or `glPixelStore' is not allowed after a call to `glBegin' and before the corresponding call to `glEnd', but an error may or may not be generated.") (define-gl-procedures ((glBindAttribLocation (program GLuint) (index GLuint) (name const-GLchar-*) -> void)) "Associates a generic vertex attribute index with a named attribute variable. PROGRAM Specifies the handle of the program object in which the association is to be made. INDEX Specifies the index of the generic vertex attribute to be bound. NAME Specifies a null terminated string containing the name of the vertex shader attribute variable to which INDEX is to be bound. `glBindAttribLocation' is used to associate a user-defined attribute variable in the program object specified by PROGRAM with a generic vertex attribute index. The name of the user-defined attribute variable is passed as a null terminated string in NAME. The generic vertex attribute index to be bound to this variable is specified by INDEX. When PROGRAM is made part of current state, values provided via the generic vertex attribute INDEX will modify the value of the user-defined attribute variable specified by NAME. If NAME refers to a matrix attribute variable, INDEX refers to the first column of the matrix. Other matrix columns are then automatically bound to locations INDEX+1 for a matrix of type mat2; INDEX+1 and INDEX+2 for a matrix of type mat3; and INDEX+1, INDEX+2, and INDEX+3 for a matrix of type mat4. This command makes it possible for vertex shaders to use descriptive names for attribute variables rather than generic variables that are numbered from 0 to `GL_MAX_VERTEX_ATTRIBS' -1. The values sent to each generic attribute index are part of current state, just like standard vertex attributes such as color, normal, and vertex position. If a different program object is made current by calling `glUseProgram', the generic vertex attributes are tracked in such a way that the same values will be observed by attributes in the new program object that are also bound to INDEX. Attribute variable name-to-generic attribute index bindings for a program object can be explicitly assigned at any time by calling `glBindAttribLocation'. Attribute bindings do not go into effect until `glLinkProgram' is called. After a program object has been linked successfully, the index values for generic attributes remain fixed (and their values can be queried) until the next link command occurs. Applications are not allowed to bind any of the standard OpenGL vertex attributes using this command, as they are bound automatically when needed. Any attribute binding that occurs after the program object has been linked will not take effect until the next time the program object is linked. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'. `GL_INVALID_OPERATION' is generated if NAME starts with the reserved prefix \"gl_\". `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if `glBindAttribLocation' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBindBuffer (target GLenum) (buffer GLuint) -> void)) "Bind a named buffer object. TARGET Specifies the target to which the buffer object is bound. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. BUFFER Specifies the name of a buffer object. `glBindBuffer' lets you create or use a named buffer object. Calling `glBindBuffer' with TARGET set to `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER' or `GL_PIXEL_UNPACK_BUFFER' and BUFFER set to the name of the new buffer object binds the buffer object name to the target. When a buffer object is bound to a target, the previous binding for that target is automatically broken. Buffer object names are unsigned integers. The value zero is reserved, but there is no default buffer object for each buffer object target. Instead, BUFFER set to zero effectively unbinds any buffer object previously bound, and restores client memory usage for that buffer object target. Buffer object names and the corresponding buffer object contents are local to the shared display-list space (see `glXCreateContext') of the current GL rendering context; two rendering contexts share buffer object names only if they also share display lists. You may use `glGenBuffers' to generate a set of new buffer object names. The state of a buffer object immediately after it is first bound is an unmapped zero-sized memory buffer with `GL_READ_WRITE' access and `GL_STATIC_DRAW' usage. While a non-zero buffer object name is bound, GL operations on the target to which it is bound affect the bound buffer object, and queries of the target to which it is bound return state from the bound buffer object. While buffer object name zero is bound, as in the initial state, attempts to modify or query state on the target to which it is bound generates an `GL_INVALID_OPERATION' error. When vertex array pointer state is changed, for example by a call to `glNormalPointer', the current buffer object binding (`GL_ARRAY_BUFFER_BINDING') is copied into the corresponding client state for the vertex array type being changed, for example `GL_NORMAL_ARRAY_BUFFER_BINDING'. While a non-zero buffer object is bound to the `GL_ARRAY_BUFFER' target, the vertex array pointer parameter that is traditionally interpreted as a pointer to client-side memory is instead interpreted as an offset within the buffer object measured in basic machine units. While a non-zero buffer object is bound to the `GL_ELEMENT_ARRAY_BUFFER' target, the indices parameter of `glDrawElements', `glDrawRangeElements', or `glMultiDrawElements' that is traditionally interpreted as a pointer to client-side memory is instead interpreted as an offset within the buffer object measured in basic machine units. While a non-zero buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target, the following commands are affected: `glGetCompressedTexImage', `glGetConvolutionFilter', `glGetHistogram', `glGetMinmax', `glGetPixelMap', `glGetPolygonStipple', `glGetSeparableFilter', `glGetTexImage', and `glReadPixels'. The pointer parameter that is traditionally interpreted as a pointer to client-side memory where the pixels are to be packed is instead interpreted as an offset within the buffer object measured in basic machine units. While a non-zero buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target, the following commands are affected: `glBitmap', `glColorSubTable', `glColorTable', `glCompressedTexImage1D', `glCompressedTexImage2D', `glCompressedTexImage3D', `glCompressedTexSubImage1D', `glCompressedTexSubImage2D', `glCompressedTexSubImage3D', `glConvolutionFilter1D', `glConvolutionFilter2D', `glDrawPixels', `glPixelMap', `glPolygonStipple', `glSeparableFilter2D', `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', and `glTexSubImage3D'. The pointer parameter that is traditionally interpreted as a pointer to client-side memory from which the pixels are to be unpacked is instead interpreted as an offset within the buffer object measured in basic machine units. A buffer object binding created with `glBindBuffer' remains active until a different buffer object name is bound to the same target, or until the bound buffer object is deleted with `glDeleteBuffers'. Once created, a named buffer object may be re-bound to any target as often as needed. However, the GL implementation may make choices about how to optimize the storage of a buffer object based on its initial binding target. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_OPERATION' is generated if `glBindBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBindTexture (target GLenum) (texture GLuint) -> void)) "Bind a named texture to a texturing target. TARGET Specifies the target to which the texture is bound. Must be either `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', or `GL_TEXTURE_CUBE_MAP'. TEXTURE Specifies the name of a texture. `glBindTexture' lets you create or use a named texture. Calling `glBindTexture' with TARGET set to `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D' or `GL_TEXTURE_CUBE_MAP' and TEXTURE set to the name of the new texture binds the texture name to the target. When a texture is bound to a target, the previous binding for that target is automatically broken. Texture names are unsigned integers. The value zero is reserved to represent the default texture for each texture target. Texture names and the corresponding texture contents are local to the shared display-list space (see `glXCreateContext') of the current GL rendering context; two rendering contexts share texture names only if they also share display lists. You may use `glGenTextures' to generate a set of new texture names. When a texture is first bound, it assumes the specified target: A texture first bound to `GL_TEXTURE_1D' becomes one-dimensional texture, a texture first bound to `GL_TEXTURE_2D' becomes two-dimensional texture, a texture first bound to `GL_TEXTURE_3D' becomes three-dimensional texture, and a texture first bound to `GL_TEXTURE_CUBE_MAP' becomes a cube-mapped texture. The state of a one-dimensional texture immediately after it is first bound is equivalent to the state of the default `GL_TEXTURE_1D' at GL initialization, and similarly for two- and three-dimensional textures and cube-mapped textures. While a texture is bound, GL operations on the target to which it is bound affect the bound texture, and queries of the target to which it is bound return state from the bound texture. If texture mapping is active on the target to which a texture is bound, the bound texture is used. In effect, the texture targets become aliases for the textures currently bound to them, and the texture name zero refers to the default textures that were bound to them at initialization. A texture binding created with `glBindTexture' remains active until a different texture is bound to the same target, or until the bound texture is deleted with `glDeleteTextures'. Once created, a named texture may be re-bound to its same original target as often as needed. It is usually much faster to use `glBindTexture' to bind an existing named texture to one of the texture targets than it is to reload the texture image using `glTexImage1D', `glTexImage2D', or `glTexImage3D'. For additional control over performance, use `glPrioritizeTextures'. `glBindTexture' is included in display lists. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TEXTURE was previously created with a target that doesn't match that of TARGET. `GL_INVALID_OPERATION' is generated if `glBindTexture' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBitmap (width GLsizei) (height GLsizei) (xorig GLfloat) (yorig GLfloat) (xmove GLfloat) (ymove GLfloat) (bitmap const-GLubyte-*) -> void)) "Draw a bitmap. WIDTH HEIGHT Specify the pixel width and height of the bitmap image. XORIG YORIG Specify the location of the origin in the bitmap image. The origin is measured from the lower left corner of the bitmap, with right and up being the positive axes. XMOVE YMOVE Specify the X and Y offsets to be added to the current raster position after the bitmap is drawn. BITMAP Specifies the address of the bitmap image. A bitmap is a binary image. When drawn, the bitmap is positioned relative to the current raster position, and frame buffer pixels corresponding to 1's in the bitmap are written using the current raster color or index. Frame buffer pixels corresponding to 0's in the bitmap are not modified. `glBitmap' takes seven arguments. The first pair specifies the width and height of the bitmap image. The second pair specifies the location of the bitmap origin relative to the lower left corner of the bitmap image. The third pair of arguments specifies X and Y offsets to be added to the current raster position after the bitmap has been drawn. The final argument is a pointer to the bitmap image itself. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a bitmap image is specified, BITMAP is treated as a byte offset into the buffer object's data store. The bitmap image is interpreted like image data for the `glDrawPixels' command, with WIDTH and HEIGHT corresponding to the width and height arguments of that command, and with TYPE set to `GL_BITMAP' and FORMAT set to `GL_COLOR_INDEX'. Modes specified using `glPixelStore' affect the interpretation of bitmap image data; modes specified using `glPixelTransfer' do not. If the current raster position is invalid, `glBitmap' is ignored. Otherwise, the lower left corner of the bitmap image is positioned at the window coordinates X_W=⌊X_R-X_O,⌋ Y_W=⌊Y_R-Y_O,⌋ where (X_R,Y_R) is the raster position and (X_O,Y_O) is the bitmap origin. Fragments are then generated for each pixel corresponding to a 1 (one) in the bitmap image. These fragments are generated using the current raster Z coordinate, color or color index, and current raster texture coordinates. They are then treated just as if they had been generated by a point, line, or polygon, including texture mapping, fogging, and all per-fragment operations such as alpha and depth testing. After the bitmap has been drawn, the X and Y coordinates of the current raster position are offset by XMOVE and YMOVE. No change is made to the Z coordinate of the current raster position, or to the current raster color, texture coordinates, or index. `GL_INVALID_VALUE' is generated if WIDTH or HEIGHT is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glBitmap' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBlendColor (red GLclampf) (green GLclampf) (blue GLclampf) (alpha GLclampf) -> void)) "Set the blend color. RED GREEN BLUE ALPHA specify the components of `GL_BLEND_COLOR' The `GL_BLEND_COLOR' may be used to calculate the source and destination blending factors. The color components are clamped to the range [0,1] before being stored. See `glBlendFunc' for a complete description of the blending operations. Initially the `GL_BLEND_COLOR' is set to (0, 0, 0, 0). `GL_INVALID_OPERATION' is generated if `glBlendColor' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBlendEquationSeparate (modeRGB GLenum) (modeAlpha GLenum) -> void)) "Set the RGB blend equation and the alpha blend equation separately. MODERGB specifies the RGB blend equation, how the red, green, and blue components of the source and destination colors are combined. It must be `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MIN', `GL_MAX'. MODEALPHA specifies the alpha blend equation, how the alpha component of the source and destination colors are combined. It must be `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MIN', `GL_MAX'. The blend equations determines how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). This function specifies one blend equation for the RGB-color components and one blend equation for the alpha component. The blend equations use the source and destination blend factors specified by either `glBlendFunc' or `glBlendFuncSeparate'. See `glBlendFunc' or `glBlendFuncSeparate' for a description of the various blend factors. In the equations that follow, source and destination color components are referred to as (R_S,G_SB_SA_S) and (R_D,G_DB_DA_D) , respectively. The result color is referred to as (R_R,G_RB_RA_R) . The source and destination blend factors are denoted (S_R,S_GS_BS_A) and (D_R,D_GD_BD_A) , respectively. For these equations all color components are understood to have values in the range [0,1] . *Mode* *RGB Components*, *Alpha Component* `GL_FUNC_ADD' RR=R_S\u2062S_R+R_D\u2062D_R GR=G_S\u2062S_G+G_D\u2062D_G BR=B_S\u2062S_B+B_D\u2062D_B , AR=A_S\u2062S_A+A_D\u2062D_A `GL_FUNC_SUBTRACT' RR=R_S\u2062S_R-R_D\u2062D_R GR=G_S\u2062S_G-G_D\u2062D_G BR=B_S\u2062S_B-B_D\u2062D_B , AR=A_S\u2062S_A-A_D\u2062D_A `GL_FUNC_REVERSE_SUBTRACT' RR=R_D\u2062D_R-R_S\u2062S_R GR=G_D\u2062D_G-G_S\u2062S_G BR=B_D\u2062D_B-B_S\u2062S_B , AR=A_D\u2062D_A-A_S\u2062S_A `GL_MIN' RR=MIN\u2061(R_S,R_D) GR=MIN\u2061(G_S,G_D) BR=MIN\u2061(B_S,B_D) , AR=MIN\u2061(A_S,A_D) `GL_MAX' RR=MAX\u2061(R_S,R_D) GR=MAX\u2061(G_S,G_D) BR=MAX\u2061(B_S,B_D) , AR=MAX\u2061(A_S,A_D) The results of these equations are clamped to the range [0,1] . The `GL_MIN' and `GL_MAX' equations are useful for applications that analyze image data (image thresholding against a constant color, for example). The `GL_FUNC_ADD' equation is useful for antialiasing and transparency, among other things. Initially, both the RGB blend equation and the alpha blend equation are set to `GL_FUNC_ADD'. `GL_INVALID_ENUM' is generated if either MODERGB or MODEALPHA is not one of `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MAX', or `GL_MIN'. `GL_INVALID_OPERATION' is generated if `glBlendEquationSeparate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBlendEquation (mode GLenum) -> void)) "Specify the equation used for both the RGB blend equation and the Alpha blend equation. MODE specifies how source and destination colors are combined. It must be `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MIN', `GL_MAX'. The blend equations determine how a new pixel (the ''source'' color) is combined with a pixel already in the framebuffer (the ''destination'' color). This function sets both the RGB blend equation and the alpha blend equation to a single equation. These equations use the source and destination blend factors specified by either `glBlendFunc' or `glBlendFuncSeparate'. See `glBlendFunc' or `glBlendFuncSeparate' for a description of the various blend factors. In the equations that follow, source and destination color components are referred to as (R_S,G_SB_SA_S) and (R_D,G_DB_DA_D) , respectively. The result color is referred to as (R_R,G_RB_RA_R) . The source and destination blend factors are denoted (S_R,S_GS_BS_A) and (D_R,D_GD_BD_A) , respectively. For these equations all color components are understood to have values in the range [0,1] . *Mode* *RGB Components*, *Alpha Component* `GL_FUNC_ADD' RR=R_S\u2062S_R+R_D\u2062D_R GR=G_S\u2062S_G+G_D\u2062D_G BR=B_S\u2062S_B+B_D\u2062D_B , AR=A_S\u2062S_A+A_D\u2062D_A `GL_FUNC_SUBTRACT' RR=R_S\u2062S_R-R_D\u2062D_R GR=G_S\u2062S_G-G_D\u2062D_G BR=B_S\u2062S_B-B_D\u2062D_B , AR=A_S\u2062S_A-A_D\u2062D_A `GL_FUNC_REVERSE_SUBTRACT' RR=R_D\u2062D_R-R_S\u2062S_R GR=G_D\u2062D_G-G_S\u2062S_G BR=B_D\u2062D_B-B_S\u2062S_B , AR=A_D\u2062D_A-A_S\u2062S_A `GL_MIN' RR=MIN\u2061(R_S,R_D) GR=MIN\u2061(G_S,G_D) BR=MIN\u2061(B_S,B_D) , AR=MIN\u2061(A_S,A_D) `GL_MAX' RR=MAX\u2061(R_S,R_D) GR=MAX\u2061(G_S,G_D) BR=MAX\u2061(B_S,B_D) , AR=MAX\u2061(A_S,A_D) The results of these equations are clamped to the range [0,1] . The `GL_MIN' and `GL_MAX' equations are useful for applications that analyze image data (image thresholding against a constant color, for example). The `GL_FUNC_ADD' equation is useful for antialiasing and transparency, among other things. Initially, both the RGB blend equation and the alpha blend equation are set to `GL_FUNC_ADD'. `GL_INVALID_ENUM' is generated if MODE is not one of `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MAX', or `GL_MIN'. `GL_INVALID_OPERATION' is generated if `glBlendEquation' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBlendFuncSeparate (srcRGB GLenum) (dstRGB GLenum) (srcAlpha GLenum) (dstAlpha GLenum) -> void)) "Specify pixel arithmetic for RGB and alpha components separately. SRCRGB Specifies how the red, green, and blue blending factors are computed. The following symbolic constants are accepted: `GL_ZERO', `GL_ONE', `GL_SRC_COLOR', `GL_ONE_MINUS_SRC_COLOR', `GL_DST_COLOR', `GL_ONE_MINUS_DST_COLOR', `GL_SRC_ALPHA', `GL_ONE_MINUS_SRC_ALPHA', `GL_DST_ALPHA', `GL_ONE_MINUS_DST_ALPHA', `GL_CONSTANT_COLOR', `GL_ONE_MINUS_CONSTANT_COLOR', `GL_CONSTANT_ALPHA', `GL_ONE_MINUS_CONSTANT_ALPHA', and `GL_SRC_ALPHA_SATURATE'. The initial value is `GL_ONE'. DSTRGB Specifies how the red, green, and blue destination blending factors are computed. The following symbolic constants are accepted: `GL_ZERO', `GL_ONE', `GL_SRC_COLOR', `GL_ONE_MINUS_SRC_COLOR', `GL_DST_COLOR', `GL_ONE_MINUS_DST_COLOR', `GL_SRC_ALPHA', `GL_ONE_MINUS_SRC_ALPHA', `GL_DST_ALPHA', `GL_ONE_MINUS_DST_ALPHA'. `GL_CONSTANT_COLOR', `GL_ONE_MINUS_CONSTANT_COLOR', `GL_CONSTANT_ALPHA', and `GL_ONE_MINUS_CONSTANT_ALPHA'. The initial value is `GL_ZERO'. SRCALPHA Specified how the alpha source blending factor is computed. The same symbolic constants are accepted as for SRCRGB. The initial value is `GL_ONE'. DSTALPHA Specified how the alpha destination blending factor is computed. The same symbolic constants are accepted as for DSTRGB. The initial value is `GL_ZERO'. In RGBA mode, pixels can be drawn using a function that blends the incoming (source) RGBA values with the RGBA values that are already in the frame buffer (the destination values). Blending is initially disabled. Use `glEnable' and `glDisable' with argument `GL_BLEND' to enable and disable blending. `glBlendFuncSeparate' defines the operation of blending when it is enabled. SRCRGB specifies which method is used to scale the source RGB-color components. DSTRGB specifies which method is used to scale the destination RGB-color components. Likewise, SRCALPHA specifies which method is used to scale the source alpha color component, and DSTALPHA specifies which method is used to scale the destination alpha component. The possible methods are described in the following table. Each method defines four scale factors, one each for red, green, blue, and alpha. In the table and in subsequent equations, source and destination color components are referred to as (R_S,G_SB_SA_S) and (R_D,G_DB_DA_D) . The color specified by `glBlendColor' is referred to as (R_C,G_CB_CA_C) . They are understood to have integer values between 0 and (K_R,K_GK_BK_A) , where K_C=2^M_C,-1 and (M_R,M_GM_BM_A) is the number of red, green, blue, and alpha bitplanes. Source and destination scale factors are referred to as (S_R,S_GS_BS_A) and (D_R,D_GD_BD_A) . All scale factors have range [0,1] . *Parameter* *RGB Factor*, *Alpha Factor* `GL_ZERO' (0,00) , 0 `GL_ONE' (1,11) , 1 `GL_SRC_COLOR' (R_S/K_R,G_S/K_GB_S/K_B) , A_S/K_A `GL_ONE_MINUS_SRC_COLOR' (1,111)-(R_S/K_R,G_S/K_GB_S/K_B) , 1-A_S/K_A `GL_DST_COLOR' (R_D/K_R,G_D/K_GB_D/K_B) , A_D/K_A `GL_ONE_MINUS_DST_COLOR' (1,11)-(R_D/K_R,G_D/K_GB_D/K_B) , 1-A_D/K_A `GL_SRC_ALPHA' (A_S/K_A,A_S/K_AA_S/K_A) , A_S/K_A `GL_ONE_MINUS_SRC_ALPHA' (1,11)-(A_S/K_A,A_S/K_AA_S/K_A) , 1-A_S/K_A `GL_DST_ALPHA' (A_D/K_A,A_D/K_AA_D/K_A) , A_D/K_A `GL_ONE_MINUS_DST_ALPHA' (1,11)-(A_D/K_A,A_D/K_AA_D/K_A) , 1-A_D/K_A `GL_CONSTANT_COLOR' (R_C,G_CB_C) , A_C `GL_ONE_MINUS_CONSTANT_COLOR' (1,11)-(R_C,G_CB_C) , 1-A_C `GL_CONSTANT_ALPHA' (A_C,A_CA_C) , A_C `GL_ONE_MINUS_CONSTANT_ALPHA' (1,11)-(A_C,A_CA_C) , 1-A_C `GL_SRC_ALPHA_SATURATE' (I,II) , 1 In the table, I=MIN\u2061(A_S,1-A_D,) To determine the blended RGBA values of a pixel when drawing in RGBA mode, the system uses the following equations: R_D=MIN\u2061(K_R,R_S\u2062S_R+R_D\u2062D_R) G_D=MIN\u2061(K_G,G_S\u2062S_G+G_D\u2062D_G) B_D=MIN\u2061(K_B,B_S\u2062S_B+B_D\u2062D_B) A_D=MIN\u2061(K_A,A_S\u2062S_A+A_D\u2062D_A) Despite the apparent precision of the above equations, blending arithmetic is not exactly specified, because blending operates with imprecise integer color values. However, a blend factor that should be equal to 1 is guaranteed not to modify its multiplicand, and a blend factor equal to 0 reduces its multiplicand to 0. For example, when SRCRGB is `GL_SRC_ALPHA', DSTRGB is `GL_ONE_MINUS_SRC_ALPHA', and A_S is equal to K_A , the equations reduce to simple replacement: R_D=R_S G_D=G_S B_D=B_S A_D=A_S `GL_INVALID_ENUM' is generated if either SRCRGB or DSTRGB is not an accepted value. `GL_INVALID_OPERATION' is generated if `glBlendFuncSeparate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBlendFunc (sfactor GLenum) (dfactor GLenum) -> void)) "Specify pixel arithmetic. SFACTOR Specifies how the red, green, blue, and alpha source blending factors are computed. The following symbolic constants are accepted: `GL_ZERO', `GL_ONE', `GL_SRC_COLOR', `GL_ONE_MINUS_SRC_COLOR', `GL_DST_COLOR', `GL_ONE_MINUS_DST_COLOR', `GL_SRC_ALPHA', `GL_ONE_MINUS_SRC_ALPHA', `GL_DST_ALPHA', `GL_ONE_MINUS_DST_ALPHA', `GL_CONSTANT_COLOR', `GL_ONE_MINUS_CONSTANT_COLOR', `GL_CONSTANT_ALPHA', `GL_ONE_MINUS_CONSTANT_ALPHA', and `GL_SRC_ALPHA_SATURATE'. The initial value is `GL_ONE'. DFACTOR Specifies how the red, green, blue, and alpha destination blending factors are computed. The following symbolic constants are accepted: `GL_ZERO', `GL_ONE', `GL_SRC_COLOR', `GL_ONE_MINUS_SRC_COLOR', `GL_DST_COLOR', `GL_ONE_MINUS_DST_COLOR', `GL_SRC_ALPHA', `GL_ONE_MINUS_SRC_ALPHA', `GL_DST_ALPHA', `GL_ONE_MINUS_DST_ALPHA'. `GL_CONSTANT_COLOR', `GL_ONE_MINUS_CONSTANT_COLOR', `GL_CONSTANT_ALPHA', and `GL_ONE_MINUS_CONSTANT_ALPHA'. The initial value is `GL_ZERO'. In RGBA mode, pixels can be drawn using a function that blends the incoming (source) RGBA values with the RGBA values that are already in the frame buffer (the destination values). Blending is initially disabled. Use `glEnable' and `glDisable' with argument `GL_BLEND' to enable and disable blending. `glBlendFunc' defines the operation of blending when it is enabled. SFACTOR specifies which method is used to scale the source color components. DFACTOR specifies which method is used to scale the destination color components. The possible methods are described in the following table. Each method defines four scale factors, one each for red, green, blue, and alpha. In the table and in subsequent equations, source and destination color components are referred to as (R_S,G_SB_SA_S) and (R_D,G_DB_DA_D) . The color specified by `glBlendColor' is referred to as (R_C,G_CB_CA_C) . They are understood to have integer values between 0 and (K_R,K_GK_BK_A) , where K_C=2^M_C,-1 and (M_R,M_GM_BM_A) is the number of red, green, blue, and alpha bitplanes. Source and destination scale factors are referred to as (S_R,S_GS_BS_A) and (D_R,D_GD_BD_A) . The scale factors described in the table, denoted (F_R,F_GF_BF_A) , represent either source or destination factors. All scale factors have range [0,1] . *Parameter* * (F_R,F_GF_BF_A) * `GL_ZERO' (0,000) `GL_ONE' (1,111) `GL_SRC_COLOR' (R_S/K_R,G_S/K_GB_S/K_BA_S/K_A) `GL_ONE_MINUS_SRC_COLOR' (1,111)-(R_S/K_R,G_S/K_GB_S/K_BA_S/K_A) `GL_DST_COLOR' (R_D/K_R,G_D/K_GB_D/K_BA_D/K_A) `GL_ONE_MINUS_DST_COLOR' (1,111)-(R_D/K_R,G_D/K_GB_D/K_BA_D/K_A) `GL_SRC_ALPHA' (A_S/K_A,A_S/K_AA_S/K_AA_S/K_A) `GL_ONE_MINUS_SRC_ALPHA' (1,111)-(A_S/K_A,A_S/K_AA_S/K_AA_S/K_A) `GL_DST_ALPHA' (A_D/K_A,A_D/K_AA_D/K_AA_D/K_A) `GL_ONE_MINUS_DST_ALPHA' (1,111)-(A_D/K_A,A_D/K_AA_D/K_AA_D/K_A) `GL_CONSTANT_COLOR' (R_C,G_CB_CA_C) `GL_ONE_MINUS_CONSTANT_COLOR' (1,111)-(R_C,G_CB_CA_C) `GL_CONSTANT_ALPHA' (A_C,A_CA_CA_C) `GL_ONE_MINUS_CONSTANT_ALPHA' (1,111)-(A_C,A_CA_CA_C) `GL_SRC_ALPHA_SATURATE' (I,II1) In the table, I=MIN\u2061(A_S,K_A-A_D)/K_A To determine the blended RGBA values of a pixel when drawing in RGBA mode, the system uses the following equations: R_D=MIN\u2061(K_R,R_S\u2062S_R+R_D\u2062D_R) G_D=MIN\u2061(K_G,G_S\u2062S_G+G_D\u2062D_G) B_D=MIN\u2061(K_B,B_S\u2062S_B+B_D\u2062D_B) A_D=MIN\u2061(K_A,A_S\u2062S_A+A_D\u2062D_A) Despite the apparent precision of the above equations, blending arithmetic is not exactly specified, because blending operates with imprecise integer color values. However, a blend factor that should be equal to 1 is guaranteed not to modify its multiplicand, and a blend factor equal to 0 reduces its multiplicand to 0. For example, when SFACTOR is `GL_SRC_ALPHA', DFACTOR is `GL_ONE_MINUS_SRC_ALPHA', and A_S is equal to K_A , the equations reduce to simple replacement: R_D=R_S G_D=G_S B_D=B_S A_D=A_S `GL_INVALID_ENUM' is generated if either SFACTOR or DFACTOR is not an accepted value. `GL_INVALID_OPERATION' is generated if `glBlendFunc' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBufferData (target GLenum) (size GLsizeiptr) (data const-GLvoid-*) (usage GLenum) -> void)) "Creates and initializes a buffer object's data store. TARGET Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. SIZE Specifies the size in bytes of the buffer object's new data store. DATA Specifies a pointer to data that will be copied into the data store for initialization, or `NULL' if no data is to be copied. USAGE Specifies the expected usage pattern of the data store. The symbolic constant must be `GL_STREAM_DRAW', `GL_STREAM_READ', `GL_STREAM_COPY', `GL_STATIC_DRAW', `GL_STATIC_READ', `GL_STATIC_COPY', `GL_DYNAMIC_DRAW', `GL_DYNAMIC_READ', or `GL_DYNAMIC_COPY'. `glBufferData' creates a new data store for the buffer object currently bound to TARGET. Any pre-existing data store is deleted. The new data store is created with the specified SIZE in bytes and USAGE. If DATA is not `NULL', the data store is initialized with data from this pointer. In its initial state, the new data store is not mapped, it has a `NULL' mapped pointer, and its mapped access is `GL_READ_WRITE'. USAGE is a hint to the GL implementation as to how a buffer object's data store will be accessed. This enables the GL implementation to make more intelligent decisions that may significantly impact buffer object performance. It does not, however, constrain the actual usage of the data store. USAGE can be broken down into two parts: first, the frequency of access (modification and usage), and second, the nature of that access. The frequency of access may be one of these: STREAM The data store contents will be modified once and used at most a few times. STATIC The data store contents will be modified once and used many times. DYNAMIC The data store contents will be modified repeatedly and used many times. The nature of access may be one of these: DRAW The data store contents are modified by the application, and used as the source for GL drawing and image specification commands. READ The data store contents are modified by reading data from the GL, and used to return that data when queried by the application. COPY The data store contents are modified by reading data from the GL, and used as the source for GL drawing and image specification commands. `GL_INVALID_ENUM' is generated if TARGET is not `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. `GL_INVALID_ENUM' is generated if USAGE is not `GL_STREAM_DRAW', `GL_STREAM_READ', `GL_STREAM_COPY', `GL_STATIC_DRAW', `GL_STATIC_READ', `GL_STATIC_COPY', `GL_DYNAMIC_DRAW', `GL_DYNAMIC_READ', or `GL_DYNAMIC_COPY'. `GL_INVALID_VALUE' is generated if SIZE is negative. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_OUT_OF_MEMORY' is generated if the GL is unable to create a data store with the specified SIZE. `GL_INVALID_OPERATION' is generated if `glBufferData' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glBufferSubData (target GLenum) (offset GLintptr) (size GLsizeiptr) (data const-GLvoid-*) -> void)) "Updates a subset of a buffer object's data store. TARGET Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. OFFSET Specifies the offset into the buffer object's data store where data replacement will begin, measured in bytes. SIZE Specifies the size in bytes of the data store region being replaced. DATA Specifies a pointer to the new data that will be copied into the data store. `glBufferSubData' redefines some or all of the data store for the buffer object currently bound to TARGET. Data starting at byte offset OFFSET and extending for SIZE bytes is copied to the data store from the memory pointed to by DATA. An error is thrown if OFFSET and SIZE together define a range beyond the bounds of the buffer object's data store. `GL_INVALID_ENUM' is generated if TARGET is not `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. `GL_INVALID_VALUE' is generated if OFFSET or SIZE is negative, or if together they define a region of memory that extends beyond the buffer object's allocated data store. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_INVALID_OPERATION' is generated if the buffer object being updated is mapped. `GL_INVALID_OPERATION' is generated if `glBufferSubData' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCallLists (n GLsizei) (type GLenum) (lists const-GLvoid-*) -> void)) "Execute a list of display lists. N Specifies the number of display lists to be executed. TYPE Specifies the type of values in LISTS. Symbolic constants `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', `GL_2_BYTES', `GL_3_BYTES', and `GL_4_BYTES' are accepted. LISTS Specifies the address of an array of name offsets in the display list. The pointer type is void because the offsets can be bytes, shorts, ints, or floats, depending on the value of TYPE. `glCallLists' causes each display list in the list of names passed as LISTS to be executed. As a result, the commands saved in each display list are executed in order, just as if they were called without using a display list. Names of display lists that have not been defined are ignored. `glCallLists' provides an efficient means for executing more than one display list. TYPE allows lists with various name formats to be accepted. The formats are as follows: `GL_BYTE' LISTS is treated as an array of signed bytes, each in the range -128 through 127. `GL_UNSIGNED_BYTE' LISTS is treated as an array of unsigned bytes, each in the range 0 through 255. `GL_SHORT' LISTS is treated as an array of signed two-byte integers, each in the range -32768 through 32767. `GL_UNSIGNED_SHORT' LISTS is treated as an array of unsigned two-byte integers, each in the range 0 through 65535. `GL_INT' LISTS is treated as an array of signed four-byte integers. `GL_UNSIGNED_INT' LISTS is treated as an array of unsigned four-byte integers. `GL_FLOAT' LISTS is treated as an array of four-byte floating-point values. `GL_2_BYTES' LISTS is treated as an array of unsigned bytes. Each pair of bytes specifies a single display-list name. The value of the pair is computed as 256 times the unsigned value of the first byte plus the unsigned value of the second byte. `GL_3_BYTES' LISTS is treated as an array of unsigned bytes. Each triplet of bytes specifies a single display-list name. The value of the triplet is computed as 65536 times the unsigned value of the first byte, plus 256 times the unsigned value of the second byte, plus the unsigned value of the third byte. `GL_4_BYTES' LISTS is treated as an array of unsigned bytes. Each quadruplet of bytes specifies a single display-list name. The value of the quadruplet is computed as 16777216 times the unsigned value of the first byte, plus 65536 times the unsigned value of the second byte, plus 256 times the unsigned value of the third byte, plus the unsigned value of the fourth byte. The list of display-list names is not null-terminated. Rather, N specifies how many names are to be taken from LISTS. An additional level of indirection is made available with the `glListBase' command, which specifies an unsigned offset that is added to each display-list name specified in LISTS before that display list is executed. `glCallLists' can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit must be at least 64, and it depends on the implementation. GL state is not saved and restored across a call to `glCallLists'. Thus, changes made to GL state during the execution of the display lists remain after execution is completed. Use `glPushAttrib', `glPopAttrib', `glPushMatrix', and `glPopMatrix' to preserve GL state across `glCallLists' calls. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_ENUM' is generated if TYPE is not one of `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', `GL_2_BYTES', `GL_3_BYTES', `GL_4_BYTES'.") (define-gl-procedures ((glCallList (list GLuint) -> void)) "Execute a display list. LIST Specifies the integer name of the display list to be executed. `glCallList' causes the named display list to be executed. The commands saved in the display list are executed in order, just as if they were called without using a display list. If LIST has not been defined as a display list, `glCallList' is ignored. `glCallList' can appear inside a display list. To avoid the possibility of infinite recursion resulting from display lists calling one another, a limit is placed on the nesting level of display lists during display-list execution. This limit is at least 64, and it depends on the implementation. GL state is not saved and restored across a call to `glCallList'. Thus, changes made to GL state during the execution of a display list remain after execution of the display list is completed. Use `glPushAttrib', `glPopAttrib', `glPushMatrix', and `glPopMatrix' to preserve GL state across `glCallList' calls.") (define-gl-procedures ((glClearAccum (red GLfloat) (green GLfloat) (blue GLfloat) (alpha GLfloat) -> void)) "Specify clear values for the accumulation buffer. RED GREEN BLUE ALPHA Specify the red, green, blue, and alpha values used when the accumulation buffer is cleared. The initial values are all 0. `glClearAccum' specifies the red, green, blue, and alpha values used by `glClear' to clear the accumulation buffer. Values specified by `glClearAccum' are clamped to the range [-1,1] . `GL_INVALID_OPERATION' is generated if `glClearAccum' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClearColor (red GLclampf) (green GLclampf) (blue GLclampf) (alpha GLclampf) -> void)) "Specify clear values for the color buffers. RED GREEN BLUE ALPHA Specify the red, green, blue, and alpha values used when the color buffers are cleared. The initial values are all 0. `glClearColor' specifies the red, green, blue, and alpha values used by `glClear' to clear the color buffers. Values specified by `glClearColor' are clamped to the range [0,1] . `GL_INVALID_OPERATION' is generated if `glClearColor' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClearDepth (depth GLclampd) -> void)) "Specify the clear value for the depth buffer. DEPTH Specifies the depth value used when the depth buffer is cleared. The initial value is 1. `glClearDepth' specifies the depth value used by `glClear' to clear the depth buffer. Values specified by `glClearDepth' are clamped to the range [0,1] . `GL_INVALID_OPERATION' is generated if `glClearDepth' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClearIndex (c GLfloat) -> void)) "Specify the clear value for the color index buffers. C Specifies the index used when the color index buffers are cleared. The initial value is 0. `glClearIndex' specifies the index used by `glClear' to clear the color index buffers. C is not clamped. Rather, C is converted to a fixed-point value with unspecified precision to the right of the binary point. The integer part of this value is then masked with 2^M-1 , where M is the number of bits in a color index stored in the frame buffer. `GL_INVALID_OPERATION' is generated if `glClearIndex' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClearStencil (s GLint) -> void)) "Specify the clear value for the stencil buffer. S Specifies the index used when the stencil buffer is cleared. The initial value is 0. `glClearStencil' specifies the index used by `glClear' to clear the stencil buffer. S is masked with 2^M-1 , where M is the number of bits in the stencil buffer. `GL_INVALID_OPERATION' is generated if `glClearStencil' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClear (mask GLbitfield) -> void)) "Clear buffers to preset values. MASK Bitwise OR of masks that indicate the buffers to be cleared. The four masks are `GL_COLOR_BUFFER_BIT', `GL_DEPTH_BUFFER_BIT', `GL_ACCUM_BUFFER_BIT', and `GL_STENCIL_BUFFER_BIT'. `glClear' sets the bitplane area of the window to values previously selected by `glClearColor', `glClearIndex', `glClearDepth', `glClearStencil', and `glClearAccum'. Multiple color buffers can be cleared simultaneously by selecting more than one buffer at a time using `glDrawBuffer'. The pixel ownership test, the scissor test, dithering, and the buffer writemasks affect the operation of `glClear'. The scissor box bounds the cleared region. Alpha function, blend function, logical operation, stenciling, texture mapping, and depth-buffering are ignored by `glClear'. `glClear' takes a single argument that is the bitwise OR of several values indicating which buffer is to be cleared. The values are as follows: `GL_COLOR_BUFFER_BIT' Indicates the buffers currently enabled for color writing. `GL_DEPTH_BUFFER_BIT' Indicates the depth buffer. `GL_ACCUM_BUFFER_BIT' Indicates the accumulation buffer. `GL_STENCIL_BUFFER_BIT' Indicates the stencil buffer. The value to which each buffer is cleared depends on the setting of the clear value for that buffer. `GL_INVALID_VALUE' is generated if any bit other than the four defined bits is set in MASK. `GL_INVALID_OPERATION' is generated if `glClear' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glClientActiveTexture (texture GLenum) -> void)) "Select active texture unit. TEXTURE Specifies which texture unit to make active. The number of texture units is implementation dependent, but must be at least two. TEXTURE must be one of `GL_TEXTURE' I , where i ranges from 0 to the value of `GL_MAX_TEXTURE_COORDS' - 1, which is an implementation-dependent value. The initial value is `GL_TEXTURE0'. `glClientActiveTexture' selects the vertex array client state parameters to be modified by `glTexCoordPointer', and enabled or disabled with `glEnableClientState' or `glDisableClientState', respectively, when called with a parameter of `GL_TEXTURE_COORD_ARRAY'. `GL_INVALID_ENUM' is generated if TEXTURE is not one of `GL_TEXTURE'I , where i ranges from 0 to the value of `GL_MAX_TEXTURE_COORDS' - 1.") (define-gl-procedures ((glClipPlane (plane GLenum) (equation const-GLdouble-*) -> void)) "Specify a plane against which all geometry is clipped. PLANE Specifies which clipping plane is being positioned. Symbolic names of the form `GL_CLIP_PLANE'I, where I is an integer between 0 and `GL_MAX_CLIP_PLANES' -1 , are accepted. EQUATION Specifies the address of an array of four double-precision floating-point values. These values are interpreted as a plane equation. Geometry is always clipped against the boundaries of a six-plane frustum in X, Y, and Z. `glClipPlane' allows the specification of additional planes, not necessarily perpendicular to the X, Y, or Z axis, against which all geometry is clipped. To determine the maximum number of additional clipping planes, call `glGetIntegerv' with argument `GL_MAX_CLIP_PLANES'. All implementations support at least six such clipping planes. Because the resulting clipping region is the intersection of the defined half-spaces, it is always convex. `glClipPlane' specifies a half-space using a four-component plane equation. When `glClipPlane' is called, EQUATION is transformed by the inverse of the modelview matrix and stored in the resulting eye coordinates. Subsequent changes to the modelview matrix have no effect on the stored plane-equation components. If the dot product of the eye coordinates of a vertex with the stored plane equation components is positive or zero, the vertex is IN with respect to that clipping plane. Otherwise, it is OUT. To enable and disable clipping planes, call `glEnable' and `glDisable' with the argument `GL_CLIP_PLANE'I, where I is the plane number. All clipping planes are initially defined as (0, 0, 0, 0) in eye coordinates and are disabled. `GL_INVALID_ENUM' is generated if PLANE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glClipPlane' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColorMask (red GLboolean) (green GLboolean) (blue GLboolean) (alpha GLboolean) -> void)) "Enable and disable writing of frame buffer color components. RED GREEN BLUE ALPHA Specify whether red, green, blue, and alpha can or cannot be written into the frame buffer. The initial values are all `GL_TRUE', indicating that the color components can be written. `glColorMask' specifies whether the individual color components in the frame buffer can or cannot be written. If RED is `GL_FALSE', for example, no change is made to the red component of any pixel in any of the color buffers, regardless of the drawing operation attempted. Changes to individual bits of components cannot be controlled. Rather, changes are either enabled or disabled for entire color components. `GL_INVALID_OPERATION' is generated if `glColorMask' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColorMaterial (face GLenum) (mode GLenum) -> void)) "Cause a material color to track the current color. FACE Specifies whether front, back, or both front and back material parameters should track the current color. Accepted values are `GL_FRONT', `GL_BACK', and `GL_FRONT_AND_BACK'. The initial value is `GL_FRONT_AND_BACK'. MODE Specifies which of several material parameters track the current color. Accepted values are `GL_EMISSION', `GL_AMBIENT', `GL_DIFFUSE', `GL_SPECULAR', and `GL_AMBIENT_AND_DIFFUSE'. The initial value is `GL_AMBIENT_AND_DIFFUSE'. `glColorMaterial' specifies which material parameters track the current color. When `GL_COLOR_MATERIAL' is enabled, the material parameter or parameters specified by MODE, of the material or materials specified by FACE, track the current color at all times. To enable and disable `GL_COLOR_MATERIAL', call `glEnable' and `glDisable' with argument `GL_COLOR_MATERIAL'. `GL_COLOR_MATERIAL' is initially disabled. `GL_INVALID_ENUM' is generated if FACE or MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glColorMaterial' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColorPointer (size GLint) (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of colors. SIZE Specifies the number of components per color. Must be 3 or 4. The initial value is 4. TYPE Specifies the data type of each color component in the array. Symbolic constants `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', and `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive colors. If STRIDE is 0, the colors are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first component of the first color element in the array. The initial value is 0. `glColorPointer' specifies the location and data format of an array of color components to use when rendering. SIZE specifies the number of components per color, and must be 3 or 4. TYPE specifies the data type of each color component, and STRIDE specifies the byte stride from one color to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see `glInterleavedArrays'.) If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a color array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as color vertex array client-side state (`GL_COLOR_ARRAY_BUFFER_BINDING'). When a color array is specified, SIZE, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the color array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_COLOR_ARRAY'. If enabled, the color array is used when `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', `glDrawRangeElements', or `glArrayElement' is called. `GL_INVALID_VALUE' is generated if SIZE is not 3 or 4. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glColorSubTable (target GLenum) (start GLsizei) (count GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Respecify a portion of a color table. TARGET Must be one of `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. START The starting index of the portion of the color table to be replaced. COUNT The number of table entries to replace. FORMAT The format of the pixel data in DATA. The allowable values are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', and `GL_BGRA'. TYPE The type of the pixel data in DATA. The allowable values are `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Pointer to a one-dimensional array of pixel data that is processed to replace the specified region of the color table. `glColorSubTable' is used to respecify a contiguous portion of a color table previously defined using `glColorTable'. The pixels referenced by DATA replace the portion of the existing table from indices START to START+COUNT-1 , inclusive. This region may not include any entries outside the range of the color table as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a portion of a color table is respecified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_VALUE' is generated if START+COUNT>WIDTH . `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glColorSubTable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColorTableParameterfv (target GLenum) (pname GLenum) (params const-GLfloat-*) -> void) (glColorTableParameteriv (target GLenum) (pname GLenum) (params const-GLint-*) -> void)) "Set color lookup table parameters. TARGET The target color table. Must be `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. PNAME The symbolic name of a texture color lookup table parameter. Must be one of `GL_COLOR_TABLE_SCALE' or `GL_COLOR_TABLE_BIAS'. PARAMS A pointer to an array where the values of the parameters are stored. `glColorTableParameter' is used to specify the scale factors and bias terms applied to color components when they are loaded into a color table. TARGET indicates which color table the scale and bias terms apply to; it must be set to `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. PNAME must be `GL_COLOR_TABLE_SCALE' to set the scale factors. In this case, PARAMS points to an array of four values, which are the scale factors for red, green, blue, and alpha, in that order. PNAME must be `GL_COLOR_TABLE_BIAS' to set the bias terms. In this case, PARAMS points to an array of four values, which are the bias terms for red, green, blue, and alpha, in that order. The color tables themselves are specified by calling `glColorTable'. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an acceptable value. `GL_INVALID_OPERATION' is generated if `glColorTableParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColorTable (target GLenum) (internalformat GLenum) (width GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Define a color lookup table. TARGET Must be one of `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', `GL_POST_COLOR_MATRIX_COLOR_TABLE', `GL_PROXY_COLOR_TABLE', `GL_PROXY_POST_CONVOLUTION_COLOR_TABLE', or `GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE'. INTERNALFORMAT The internal format of the color table. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', and `GL_RGBA16'. WIDTH The number of entries in the color lookup table specified by DATA. FORMAT The format of the pixel data in DATA. The allowable values are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', and `GL_BGRA'. TYPE The type of the pixel data in DATA. The allowable values are `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Pointer to a one-dimensional array of pixel data that is processed to build the color table. `glColorTable' may be used in two ways: to test the actual size and color resolution of a lookup table given a particular set of parameters, or to load the contents of a color lookup table. Use the targets `GL_PROXY_*' for the first case and the other targets for the second case. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a color table is specified, DATA is treated as a byte offset into the buffer object's data store. If TARGET is `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE', `glColorTable' builds a color lookup table from an array of pixels. The pixel array specified by WIDTH, FORMAT, TYPE, and DATA is extracted from memory and processed just as if `glDrawPixels' were called, but processing stops after the final expansion to RGBA is completed. The four scale parameters and the four bias parameters that are defined for the table are then used to scale and bias the R, G, B, and A components of each pixel. (Use `glColorTableParameter' to set these scale and bias parameters.) Next, the R, G, B, and A values are clamped to the range [0,1] . Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , Finally, the red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in the color table. They form a one-dimensional table with indices in the range [0,WIDTH-1] . If TARGET is `GL_PROXY_*', `glColorTable' recomputes and stores the values of the proxy color table's state variables `GL_COLOR_TABLE_FORMAT', `GL_COLOR_TABLE_WIDTH', `GL_COLOR_TABLE_RED_SIZE', `GL_COLOR_TABLE_GREEN_SIZE', `GL_COLOR_TABLE_BLUE_SIZE', `GL_COLOR_TABLE_ALPHA_SIZE', `GL_COLOR_TABLE_LUMINANCE_SIZE', and `GL_COLOR_TABLE_INTENSITY_SIZE'. There is no effect on the image or state of any actual color table. If the specified color table is too large to be supported, then all the proxy state variables listed above are set to zero. Otherwise, the color table could be supported by `glColorTable' using the corresponding non-proxy target, and the proxy state variables are set as if that target were being defined. The proxy state variables can be retrieved by calling `glGetColorTableParameter' with a target of `GL_PROXY_*'. This allows the application to decide if a particular `glColorTable' command would succeed, and to determine what the resulting color table attributes would be. If a color table is enabled, and its width is non-zero, then its contents are used to replace a subset of the components of each RGBA pixel group, based on the internal format of the table. Each pixel group has color components (R, G, B, A) that are in the range [0.0,1.0] . The color components are rescaled to the size of the color lookup table to form an index. Then a subset of the components based on the internal format of the table are replaced by the table entry selected by that index. If the color components and contents of the table are represented as follows: *Representation* *Meaning* `r' Table index computed from `R' `g' Table index computed from `G' `b' Table index computed from `B' `a' Table index computed from `A' `L[i]' Luminance value at table index `i' `I[i]' Intensity value at table index `i' `R[i]' Red value at table index `i' `G[i]' Green value at table index `i' `B[i]' Blue value at table index `i' `A[i]' Alpha value at table index `i' then the result of color table lookup is as follows: ** *Resulting Texture Components* *Table Internal Format* *R*, *G*, *B*, *A* `GL_ALPHA' `R', `G', `B', `A[a]' `GL_LUMINANCE' `L[r]', `L[g]', `L[b]', `At' `GL_LUMINANCE_ALPHA' `L[r]', `L[g]', `L[b]', `A[a]' `GL_INTENSITY' `I[r]', `I[g]', `I[b]', `I[a]' `GL_RGB' `R[r]', `G[g]', `B[b]', `A' `GL_RGBA' `R[r]', `G[g]', `B[b]', `A[a]' When `GL_COLOR_TABLE' is enabled, the colors resulting from the pixel map operation (if it is enabled) are mapped by the color lookup table before being passed to the convolution operation. The colors resulting from the convolution operation are modified by the post convolution color lookup table when `GL_POST_CONVOLUTION_COLOR_TABLE' is enabled. These modified colors are then sent to the color matrix operation. Finally, if `GL_POST_COLOR_MATRIX_COLOR_TABLE' is enabled, the colors resulting from the color matrix operation are mapped by the post color matrix color lookup table before being used by the histogram operation. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero. `GL_TABLE_TOO_LARGE' is generated if the requested color table is too large to be supported by the implementation, and TARGET is not a `GL_PROXY_*' target. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glColorTable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glColor3i (red GLint) (green GLint) (blue GLint) -> void) (glColor3f (red GLfloat) (green GLfloat) (blue GLfloat) -> void) (glColor3ui (red GLuint) (green GLuint) (blue GLuint) -> void) (glColor4i (red GLint) (green GLint) (blue GLint) (alpha GLint) -> void) (glColor4f (red GLfloat) (green GLfloat) (blue GLfloat) (alpha GLfloat) -> void) (glColor4ui (red GLuint) (green GLuint) (blue GLuint) (alpha GLuint) -> void)) "Set the current color. RED GREEN BLUE Specify new red, green, and blue values for the current color. ALPHA Specifies a new alpha value for the current color. Included only in the four-argument `glColor4' commands. The GL stores both a current single-valued color index and a current four-valued RGBA color. `glColor' sets a new four-valued RGBA color. `glColor' has two major variants: `glColor3' and `glColor4'. `glColor3' variants specify new red, green, and blue values explicitly and set the current alpha value to 1.0 (full intensity) implicitly. `glColor4' variants specify all four color components explicitly. `glColor3b', `glColor4b', `glColor3s', `glColor4s', `glColor3i', and `glColor4i' take three or four signed byte, short, or long integers as arguments. When *v* is appended to the name, the color commands can take a pointer to an array of such values. Current color values are stored in floating-point format, with unspecified mantissa and exponent sizes. Unsigned integer color components, when specified, are linearly mapped to floating-point values such that the largest representable value maps to 1.0 (full intensity), and 0 maps to 0.0 (zero intensity). Signed integer color components, when specified, are linearly mapped to floating-point values such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . (Note that this mapping does not convert 0 precisely to 0.0.) Floating-point values are mapped directly. Neither floating-point nor signed integer values are clamped to the range [0,1] before the current color is updated. However, color components are clamped to this range before they are interpolated or written into a color buffer.") (define-gl-procedures ((glCompileShader (shader GLuint) -> void)) "Compiles a shader object. SHADER Specifies the shader object to be compiled. `glCompileShader' compiles the source code strings that have been stored in the shader object specified by SHADER. The compilation status will be stored as part of the shader object's state. This value will be set to `GL_TRUE' if the shader was compiled without errors and is ready for use, and `GL_FALSE' otherwise. It can be queried by calling `glGetShader' with arguments SHADER and `GL_COMPILE_STATUS'. Compilation of a shader can fail for a number of reasons as specified by the OpenGL Shading Language Specification. Whether or not the compilation was successful, information about the compilation can be obtained from the shader object's information log by calling `glGetShaderInfoLog'. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_OPERATION' is generated if `glCompileShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCompressedTexImage1D (target GLenum) (level GLint) (internalformat GLenum) (width GLsizei) (border GLint) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a one-dimensional texture image in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D' or `GL_PROXY_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the format of the compressed image data stored at address DATA. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support texture images that are at least 64 texels wide. The height of the 1D texture image is 1. BORDER Specifies the width of the border. Must be either 0 or 1. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable one-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_1D'. `glCompressedTexImage1D' loads a previously defined, and retrieved, compressed one-dimensional texture image if TARGET is `GL_TEXTURE_1D' (see `glTexImage1D'). If TARGET is `GL_PROXY_TEXTURE_1D', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. INTERNALFORMAT must be extension-specified compressed-texture format. When a texture is loaded with `glTexImage1D' using a generic compressed texture format (e.g., `GL_COMPRESSED_RGB') the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using `glCompressedTexImage1D', query the compressed texture image's size and format using `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is one of the generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexImage1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glCompressedTexImage2D (target GLenum) (level GLint) (internalformat GLenum) (width GLsizei) (height GLsizei) (border GLint) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a two-dimensional texture image in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_PROXY_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z', or `GL_PROXY_TEXTURE_CUBE_MAP'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the format of the compressed image data stored at address DATA. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 2D texture images that are at least 64 texels wide and cube-mapped texture images that are at least 16 texels wide. HEIGHT Specifies the height of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be Must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 2D texture images that are at least 64 texels high and cube-mapped texture images that are at least 16 texels high. BORDER Specifies the width of the border. Must be either 0 or 1. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_2D'. To enable and disable texturing using cube-mapped textures, call `glEnable' and `glDisable' with argument `GL_TEXTURE_CUBE_MAP'. `glCompressedTexImage2D' loads a previously defined, and retrieved, compressed two-dimensional texture image if TARGET is `GL_TEXTURE_2D' (see `glTexImage2D'). If TARGET is `GL_PROXY_TEXTURE_2D', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. INTERNALFORMAT must be an extension-specified compressed-texture format. When a texture is loaded with `glTexImage2D' using a generic compressed texture format (e.g., `GL_COMPRESSED_RGB'), the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using `glCompressedTexImage2D', query the compressed texture image's size and format using `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is one of the generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glCompressedTexImage3D (target GLenum) (level GLint) (internalformat GLenum) (width GLsizei) (height GLsizei) (depth GLsizei) (border GLint) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a three-dimensional texture image in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_3D' or `GL_PROXY_TEXTURE_3D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the format of the compressed image data stored at address DATA. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 3D texture images that are at least 16 texels wide. HEIGHT Specifies the height of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 3D texture images that are at least 16 texels high. DEPTH Specifies the depth of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 3D texture images that are at least 16 texels deep. BORDER Specifies the width of the border. Must be either 0 or 1. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable three-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_3D'. `glCompressedTexImage3D' loads a previously defined, and retrieved, compressed three-dimensional texture image if TARGET is `GL_TEXTURE_3D' (see `glTexImage3D'). If TARGET is `GL_PROXY_TEXTURE_3D', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. INTERNALFORMAT must be an extension-specified compressed-texture format. When a texture is loaded with `glTexImage2D' using a generic compressed texture format (e.g., `GL_COMPRESSED_RGB'), the GL selects from one of its extensions supporting compressed textures. In order to load the compressed texture image using `glCompressedTexImage3D', query the compressed texture image's size and format using `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is one of the generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexImage3D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glCompressedTexSubImage1D (target GLenum) (level GLint) (xoffset GLint) (width GLsizei) (format GLenum) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a one-dimensional texture subimage in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. WIDTH Specifies the width of the texture subimage. FORMAT Specifies the format of the compressed image data stored at address DATA. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable one-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_1D'. `glCompressedTexSubImage1D' redefines a contiguous subregion of an existing one-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. FORMAT must be an extension-specified compressed-texture format. The FORMAT of the compressed texture image is selected by the GL implementation that compressed it (see `glTexImage1D'), and should be queried at the time the texture was compressed with `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if FORMAT is one of these generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_COMPRESSED_SLUMINANCE', `GL_COMPRESSED_SLUMINANCE_ALPHA', `GL_COMPRESSED_SRGB', `GL_COMPRESSED_SRGBA', or `GL_COMPRESSED_SRGB_ALPHA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexSubImage1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glCompressedTexSubImage2D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (width GLsizei) (height GLsizei) (format GLenum) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a two-dimensional texture subimage in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. FORMAT Specifies the format of the compressed image data stored at address DATA. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_2D'. To enable and disable texturing using cube-mapped texture, call `glEnable' and `glDisable' with argument `GL_TEXTURE_CUBE_MAP'. `glCompressedTexSubImage2D' redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , and the y indices YOFFSET and YOFFSET+HEIGHT-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. FORMAT must be an extension-specified compressed-texture format. The FORMAT of the compressed texture image is selected by the GL implementation that compressed it (see `glTexImage2D') and should be queried at the time the texture was compressed with `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if FORMAT is one of these generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_COMPRESSED_SLUMINANCE', `GL_COMPRESSED_SLUMINANCE_ALPHA', `GL_COMPRESSED_SRGB', `GL_COMPRESSED_SRGBA', or `GL_COMPRESSED_SRGB_ALPHA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexSubImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glCompressedTexSubImage3D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (zoffset GLint) (width GLsizei) (height GLsizei) (depth GLsizei) (format GLenum) (imageSize GLsizei) (data const-GLvoid-*) -> void)) "Specify a three-dimensional texture subimage in a compressed format. TARGET Specifies the target texture. Must be `GL_TEXTURE_3D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. DEPTH Specifies the depth of the texture subimage. FORMAT Specifies the format of the compressed image data stored at address DATA. IMAGESIZE Specifies the number of unsigned bytes of image data starting at the address specified by DATA. DATA Specifies a pointer to the compressed image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable three-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_3D'. `glCompressedTexSubImage3D' redefines a contiguous subregion of an existing three-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , and the y indices YOFFSET and YOFFSET+HEIGHT-1 , and the z indices ZOFFSET and ZOFFSET+DEPTH-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. FORMAT must be an extension-specified compressed-texture format. The FORMAT of the compressed texture image is selected by the GL implementation that compressed it (see `glTexImage3D') and should be queried at the time the texture was compressed with `glGetTexLevelParameter'. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if FORMAT is one of these generic compressed internal formats: `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_COMPRESSED_SLUMINANCE', `GL_COMPRESSED_SLUMINANCE_ALPHA', `GL_COMPRESSED_SRGB', `GL_COMPRESSED_SRGBA', or `GL_COMPRESSED_SRGB_ALPHA'. `GL_INVALID_VALUE' is generated if IMAGESIZE is not consistent with the format, dimensions, and contents of the specified compressed image data. `GL_INVALID_OPERATION' is generated if parameter combinations are not supported by the specific compressed internal format as specified in the specific texture compression extension. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glCompressedTexSubImage3D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. Undefined results, including abnormal program termination, are generated if DATA is not encoded in a manner consistent with the extension specification defining the internal compression format.") (define-gl-procedures ((glConvolutionFilter1D (target GLenum) (internalformat GLenum) (width GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Define a one-dimensional convolution filter. TARGET Must be `GL_CONVOLUTION_1D'. INTERNALFORMAT The internal format of the convolution filter kernel. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. WIDTH The width of the pixel array referenced by DATA. FORMAT The format of the pixel data in DATA. The allowable values are `GL_ALPHA', `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_INTENSITY', `GL_RGB', and `GL_RGBA'. TYPE The type of the pixel data in DATA. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. DATA Pointer to a one-dimensional array of pixel data that is processed to build the convolution filter kernel. `glConvolutionFilter1D' builds a one-dimensional convolution filter kernel from an array of pixels. The pixel array specified by WIDTH, FORMAT, TYPE, and DATA is extracted from memory and processed just as if `glDrawPixels' were called, but processing stops after the final expansion to RGBA is completed. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a convolution filter is specified, DATA is treated as a byte offset into the buffer object's data store. The R, G, B, and A components of each pixel are next scaled by the four 1D `GL_CONVOLUTION_FILTER_SCALE' parameters and biased by the four 1D `GL_CONVOLUTION_FILTER_BIAS' parameters. (The scale and bias parameters are set by `glConvolutionParameter' using the `GL_CONVOLUTION_1D' target and the names `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS'. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process. Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form a one-dimensional filter kernel image indexed with coordinate I such that I starts at 0 and increases from left to right. Kernel location I is derived from the Ith pixel, counting from 0. Note that after a convolution is performed, the resulting color components are also scaled by their corresponding `GL_POST_CONVOLUTION_c_SCALE' parameters and biased by their corresponding `GL_POST_CONVOLUTION_c_BIAS' parameters (where C takes on the values *RED*, *GREEN*, *BLUE*, and *ALPHA*). These parameters are set by `glPixelTransfer'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_CONVOLUTION_1D'. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_1D' and name `GL_MAX_CONVOLUTION_WIDTH'. `GL_INVALID_OPERATION' is generated if FORMAT is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and TYPE is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if FORMAT is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and TYPE is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glConvolutionFilter1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glConvolutionFilter2D (target GLenum) (internalformat GLenum) (width GLsizei) (height GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Define a two-dimensional convolution filter. TARGET Must be `GL_CONVOLUTION_2D'. INTERNALFORMAT The internal format of the convolution filter kernel. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. WIDTH The width of the pixel array referenced by DATA. HEIGHT The height of the pixel array referenced by DATA. FORMAT The format of the pixel data in DATA. The allowable values are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE The type of the pixel data in DATA. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. DATA Pointer to a two-dimensional array of pixel data that is processed to build the convolution filter kernel. `glConvolutionFilter2D' builds a two-dimensional convolution filter kernel from an array of pixels. The pixel array specified by WIDTH, HEIGHT, FORMAT, TYPE, and DATA is extracted from memory and processed just as if `glDrawPixels' were called, but processing stops after the final expansion to RGBA is completed. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a convolution filter is specified, DATA is treated as a byte offset into the buffer object's data store. The R, G, B, and A components of each pixel are next scaled by the four 2D `GL_CONVOLUTION_FILTER_SCALE' parameters and biased by the four 2D `GL_CONVOLUTION_FILTER_BIAS' parameters. (The scale and bias parameters are set by `glConvolutionParameter' using the `GL_CONVOLUTION_2D' target and the names `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS'. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process. Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form a two-dimensional filter kernel image indexed with coordinates I and J such that I starts at zero and increases from left to right, and J starts at zero and increases from bottom to top. Kernel location I,J is derived from the Nth pixel, where N is I+J*WIDTH. Note that after a convolution is performed, the resulting color components are also scaled by their corresponding `GL_POST_CONVOLUTION_c_SCALE' parameters and biased by their corresponding `GL_POST_CONVOLUTION_c_BIAS' parameters (where C takes on the values *RED*, *GREEN*, *BLUE*, and *ALPHA*). These parameters are set by `glPixelTransfer'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_CONVOLUTION_2D'. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_2D' and name `GL_MAX_CONVOLUTION_WIDTH'. `GL_INVALID_VALUE' is generated if HEIGHT is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_2D' and name `GL_MAX_CONVOLUTION_HEIGHT'. `GL_INVALID_OPERATION' is generated if HEIGHT is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if HEIGHT is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glConvolutionFilter2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glConvolutionParameterf (target GLenum) (pname GLenum) (params GLfloat) -> void) (glConvolutionParameteri (target GLenum) (pname GLenum) (params GLint) -> void)) "Set convolution parameters. TARGET The target for the convolution parameter. Must be one of `GL_CONVOLUTION_1D', `GL_CONVOLUTION_2D', or `GL_SEPARABLE_2D'. PNAME The parameter to be set. Must be `GL_CONVOLUTION_BORDER_MODE'. PARAMS The parameter value. Must be one of `GL_REDUCE', `GL_CONSTANT_BORDER', `GL_REPLICATE_BORDER'. `glConvolutionParameter' sets the value of a convolution parameter. TARGET selects the convolution filter to be affected: `GL_CONVOLUTION_1D', `GL_CONVOLUTION_2D', or `GL_SEPARABLE_2D' for the 1D, 2D, or separable 2D filter, respectively. PNAME selects the parameter to be changed. `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS' affect the definition of the convolution filter kernel; see `glConvolutionFilter1D', `glConvolutionFilter2D', and `glSeparableFilter2D' for details. In these cases, PARAMSv is an array of four values to be applied to red, green, blue, and alpha values, respectively. The initial value for `GL_CONVOLUTION_FILTER_SCALE' is (1, 1, 1, 1), and the initial value for `GL_CONVOLUTION_FILTER_BIAS' is (0, 0, 0, 0). A PNAME value of `GL_CONVOLUTION_BORDER_MODE' controls the convolution border mode. The accepted modes are: `GL_REDUCE' The image resulting from convolution is smaller than the source image. If the filter width is WF and height is HF , and the source image width is WS and height is HS , then the convolved image width will be WS-WF+1 and height will be HS-HF+1 . (If this reduction would generate an image with zero or negative width and/or height, the output is simply null, with no error generated.) The coordinates of the image resulting from convolution are zero through WS-WF in width and zero through HS-HF in height. `GL_CONSTANT_BORDER' The image resulting from convolution is the same size as the source image, and processed as if the source image were surrounded by pixels with their color specified by the `GL_CONVOLUTION_BORDER_COLOR'. `GL_REPLICATE_BORDER' The image resulting from convolution is the same size as the source image, and processed as if the outermost pixel on the border of the source image were replicated. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if PNAME is not one of the allowable values. `GL_INVALID_ENUM' is generated if PNAME is `GL_CONVOLUTION_BORDER_MODE' and PARAMS is not one of `GL_REDUCE', `GL_CONSTANT_BORDER', or `GL_REPLICATE_BORDER'. `GL_INVALID_OPERATION' is generated if `glConvolutionParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyColorSubTable (target GLenum) (start GLsizei) (x GLint) (y GLint) (width GLsizei) -> void)) "Respecify a portion of a color table. TARGET Must be one of `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. START The starting index of the portion of the color table to be replaced. X Y The window coordinates of the left corner of the row of pixels to be copied. WIDTH The number of table entries to replace. `glCopyColorSubTable' is used to respecify a contiguous portion of a color table previously defined using `glColorTable'. The pixels copied from the framebuffer replace the portion of the existing table from indices START to START+X-1 , inclusive. This region may not include any entries outside the range of the color table, as was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. `GL_INVALID_VALUE' is generated if TARGET is not a previously defined color table. `GL_INVALID_VALUE' is generated if TARGET is not one of the allowable values. `GL_INVALID_VALUE' is generated if START+X>WIDTH . `GL_INVALID_OPERATION' is generated if `glCopyColorSubTable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyColorTable (target GLenum) (internalformat GLenum) (x GLint) (y GLint) (width GLsizei) -> void)) "Copy pixels into a color table. TARGET The color table target. Must be `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. INTERNALFORMAT The internal storage format of the texture image. Must be one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. X The x coordinate of the lower-left corner of the pixel rectangle to be transferred to the color table. Y The y coordinate of the lower-left corner of the pixel rectangle to be transferred to the color table. WIDTH The width of the pixel rectangle. `glCopyColorTable' loads a color table with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glColorTable'). The screen-aligned pixel rectangle with lower-left corner at (X,\\ Y) having width WIDTH and height 1 is loaded into the color table. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined. The pixels in the rectangle are processed just as if `glReadPixels' were called, with INTERNALFORMAT set to RGBA, but processing stops after the final conversion to RGBA. The four scale parameters and the four bias parameters that are defined for the table are then used to scale and bias the R, G, B, and A components of each pixel. The scale and bias parameters are set by calling `glColorTableParameter'. Next, the R, G, B, and A values are clamped to the range [0,1] . Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , Finally, the red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in the color table. They form a one-dimensional table with indices in the range [0,WIDTH-1] . `GL_INVALID_ENUM' is generated when TARGET is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not one of the allowable values. `GL_TABLE_TOO_LARGE' is generated if the requested color table is too large to be supported by the implementation. `GL_INVALID_OPERATION' is generated if `glCopyColorTable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyConvolutionFilter1D (target GLenum) (internalformat GLenum) (x GLint) (y GLint) (width GLsizei) -> void)) "Copy pixels into a one-dimensional convolution filter. TARGET Must be `GL_CONVOLUTION_1D'. INTERNALFORMAT The internal format of the convolution filter kernel. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. X Y The window space coordinates of the lower-left coordinate of the pixel array to copy. WIDTH The width of the pixel array to copy. `glCopyConvolutionFilter1D' defines a one-dimensional convolution filter kernel with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glConvolutionFilter1D'). The screen-aligned pixel rectangle with lower-left corner at (X,\\ Y), width WIDTH and height 1 is used to define the convolution filter. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined. The pixels in the rectangle are processed exactly as if `glReadPixels' had been called with FORMAT set to RGBA, but the process stops just before final conversion. The R, G, B, and A components of each pixel are next scaled by the four 1D `GL_CONVOLUTION_FILTER_SCALE' parameters and biased by the four 1D `GL_CONVOLUTION_FILTER_BIAS' parameters. (The scale and bias parameters are set by `glConvolutionParameter' using the `GL_CONVOLUTION_1D' target and the names `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS'. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process. Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. Pixel ordering is such that lower x screen coordinates correspond to lower I filter image coordinates. Note that after a convolution is performed, the resulting color components are also scaled by their corresponding `GL_POST_CONVOLUTION_c_SCALE' parameters and biased by their corresponding `GL_POST_CONVOLUTION_c_BIAS' parameters (where C takes on the values *RED*, *GREEN*, *BLUE*, and *ALPHA*). These parameters are set by `glPixelTransfer'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_CONVOLUTION_1D'. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_1D' and name `GL_MAX_CONVOLUTION_WIDTH'. `GL_INVALID_OPERATION' is generated if `glCopyConvolutionFilter1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyConvolutionFilter2D (target GLenum) (internalformat GLenum) (x GLint) (y GLint) (width GLsizei) (height GLsizei) -> void)) "Copy pixels into a two-dimensional convolution filter. TARGET Must be `GL_CONVOLUTION_2D'. INTERNALFORMAT The internal format of the convolution filter kernel. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. X Y The window space coordinates of the lower-left coordinate of the pixel array to copy. WIDTH The width of the pixel array to copy. HEIGHT The height of the pixel array to copy. `glCopyConvolutionFilter2D' defines a two-dimensional convolution filter kernel with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glConvolutionFilter2D'). The screen-aligned pixel rectangle with lower-left corner at (X,\\ Y), width WIDTH and height HEIGHT is used to define the convolution filter. If any pixels within this region are outside the window that is associated with the GL context, the values obtained for those pixels are undefined. The pixels in the rectangle are processed exactly as if `glReadPixels' had been called with FORMAT set to RGBA, but the process stops just before final conversion. The R, G, B, and A components of each pixel are next scaled by the four 2D `GL_CONVOLUTION_FILTER_SCALE' parameters and biased by the four 2D `GL_CONVOLUTION_FILTER_BIAS' parameters. (The scale and bias parameters are set by `glConvolutionParameter' using the `GL_CONVOLUTION_2D' target and the names `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS'. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process. Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_ALPHA' , , , A , , `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. Pixel ordering is such that lower x screen coordinates correspond to lower I filter image coordinates, and lower y screen coordinates correspond to lower J filter image coordinates. Note that after a convolution is performed, the resulting color components are also scaled by their corresponding `GL_POST_CONVOLUTION_c_SCALE' parameters and biased by their corresponding `GL_POST_CONVOLUTION_c_BIAS' parameters (where C takes on the values *RED*, *GREEN*, *BLUE*, and *ALPHA*). These parameters are set by `glPixelTransfer'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_CONVOLUTION_2D'. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_2D' and name `GL_MAX_CONVOLUTION_WIDTH'. `GL_INVALID_VALUE' is generated if HEIGHT is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_CONVOLUTION_2D' and name `GL_MAX_CONVOLUTION_HEIGHT'. `GL_INVALID_OPERATION' is generated if `glCopyConvolutionFilter2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyPixels (x GLint) (y GLint) (width GLsizei) (height GLsizei) (type GLenum) -> void)) "Copy pixels in the frame buffer. X Y Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. WIDTH HEIGHT Specify the dimensions of the rectangular region of pixels to be copied. Both must be nonnegative. TYPE Specifies whether color values, depth values, or stencil values are to be copied. Symbolic constants `GL_COLOR', `GL_DEPTH', and `GL_STENCIL' are accepted. `glCopyPixels' copies a screen-aligned rectangle of pixels from the specified frame buffer location to a region relative to the current raster position. Its operation is well defined only if the entire pixel source region is within the exposed portion of the window. Results of copies from outside the window, or from regions of the window that are not exposed, are hardware dependent and undefined. X and Y specify the window coordinates of the lower left corner of the rectangular region to be copied. WIDTH and HEIGHT specify the dimensions of the rectangular region to be copied. Both WIDTH and HEIGHT must not be negative. Several parameters control the processing of the pixel data while it is being copied. These parameters are set with three commands: `glPixelTransfer', `glPixelMap', and `glPixelZoom'. This reference page describes the effects on `glCopyPixels' of most, but not all, of the parameters specified by these three commands. `glCopyPixels' copies values from each pixel with the lower left-hand corner at (X+I,Y+J) for 0<=I void)) "Copy pixels into a 1D texture image. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the internal format of the texture. Must be one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', `GL_DEPTH_COMPONENT32', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_RGB', `GL_R3_G3_B2', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', `GL_RGBA16', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', `GL_SLUMINANCE8_ALPHA8', `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', or `GL_SRGB8_ALPHA8'. X Y Specify the window coordinates of the left corner of the row of pixels to be copied. WIDTH Specifies the width of the texture image. Must be 0 or 2^N+2\u2061(BORDER,) for some integer N . The height of the texture image is 1. BORDER Specifies the width of the border. Must be either 0 or 1. `glCopyTexImage1D' defines a one-dimensional texture image with pixels from the current `GL_READ_BUFFER'. The screen-aligned pixel row with left corner at (X,Y) and with a length of WIDTH+2\u2061(BORDER,) defines the texture array at the mipmap level specified by LEVEL. INTERNALFORMAT specifies the internal format of the texture array. The pixels in the row are processed exactly as if `glCopyPixels' had been called, but the process stops just before final conversion. At this point all pixel component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array. Pixel ordering is such that lower X screen coordinates correspond to lower texture coordinates. If any of the pixels within the specified row of the current `GL_READ_BUFFER' are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined. `glCopyTexImage1D' defines a one-dimensional texture image with pixels from the current `GL_READ_BUFFER'. When INTERNALFORMAT is one of the sRGB types, the GL does not automatically convert the source pixels to the sRGB color space. In this case, the `glPixelMap' function can be used to accomplish the conversion. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2062MAX , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not an allowable value. `GL_INVALID_VALUE' is generated if WIDTH is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if non-power-of-two textures are not supported and the WIDTH cannot be represented as 2^N+2\u2061(BORDER,) for some integer value of N. `GL_INVALID_VALUE' is generated if BORDER is not 0 or 1. `GL_INVALID_OPERATION' is generated if `glCopyTexImage1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32' and there is no depth buffer.") (define-gl-procedures ((glCopyTexImage2D (target GLenum) (level GLint) (internalformat GLenum) (x GLint) (y GLint) (width GLsizei) (height GLsizei) (border GLint) -> void)) "Copy pixels into a 2D texture image. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the internal format of the texture. Must be one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', `GL_DEPTH_COMPONENT32', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_RGB', `GL_R3_G3_B2', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', `GL_RGBA16', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', `GL_SLUMINANCE8_ALPHA8', `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', or `GL_SRGB8_ALPHA8'. X Y Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. WIDTH Specifies the width of the texture image. Must be 0 or 2^N+2\u2061(BORDER,) for some integer N . HEIGHT Specifies the height of the texture image. Must be 0 or 2^M+2\u2061(BORDER,) for some integer M . BORDER Specifies the width of the border. Must be either 0 or 1. `glCopyTexImage2D' defines a two-dimensional texture image, or cube-map texture image with pixels from the current `GL_READ_BUFFER'. The screen-aligned pixel rectangle with lower left corner at (X, Y) and with a width of WIDTH+2\u2061(BORDER,) and a height of HEIGHT+2\u2061(BORDER,) defines the texture array at the mipmap level specified by LEVEL. INTERNALFORMAT specifies the internal format of the texture array. The pixels in the rectangle are processed exactly as if `glCopyPixels' had been called, but the process stops just before final conversion. At this point all pixel component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array. Pixel ordering is such that lower X and Y screen coordinates correspond to lower S and T texture coordinates. If any of the pixels within the specified rectangle of the current `GL_READ_BUFFER' are outside the window associated with the current rendering context, then the values obtained for those pixels are undefined. When INTERNALFORMAT is one of the sRGB types, the GL does not automatically convert the source pixels to the sRGB color space. In this case, the `glPixelMap' function can be used to accomplish the conversion. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2062MAX , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if WIDTH is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if non-power-of-two textures are not supported and the WIDTH or DEPTH cannot be represented as 2^K+2\u2061(BORDER,) for some integer K . `GL_INVALID_VALUE' is generated if BORDER is not 0 or 1. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not an accepted format. `GL_INVALID_OPERATION' is generated if `glCopyTexImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32' and there is no depth buffer.") (define-gl-procedures ((glCopyTexSubImage1D (target GLenum) (level GLint) (xoffset GLint) (x GLint) (y GLint) (width GLsizei) -> void)) "Copy a one-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies the texel offset within the texture array. X Y Specify the window coordinates of the left corner of the row of pixels to be copied. WIDTH Specifies the width of the texture subimage. `glCopyTexSubImage1D' replaces a portion of a one-dimensional texture image with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glTexSubImage1D'). The screen-aligned pixel row with left corner at (X,\\ Y), and with length WIDTH replaces the portion of the texture array with x indices XOFFSET through XOFFSET+WIDTH-1 , inclusive. The destination in the texture array may not include any texels outside the texture array as it was originally specified. The pixels in the row are processed exactly as if `glCopyPixels' had been called, but the process stops just before final conversion. At this point, all pixel component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array. It is not an error to specify a subtexture with zero width, but such a specification has no effect. If any of the pixels within the specified row of the current `GL_READ_BUFFER' are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined. No change is made to the INTERNALFORMAT, WIDTH, or BORDER parameters of the specified texture array or to texel values outside the specified subregion. `GL_INVALID_ENUM' is generated if /TARGET is not `GL_TEXTURE_1D'. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage1D' or `glCopyTexImage1D' operation. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL>LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , or (XOFFSET+WIDTH,)>(W-B,) , where W is the `GL_TEXTURE_WIDTH' and B is the `GL_TEXTURE_BORDER' of the texture image being modified. Note that W includes twice the border width.") (define-gl-procedures ((glCopyTexSubImage2D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (x GLint) (y GLint) (width GLsizei) (height GLsizei) -> void)) "Copy a two-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. X Y Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. `glCopyTexSubImage2D' replaces a rectangular portion of a two-dimensional texture image or cube-map texture image with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glTexSubImage2D'). The screen-aligned pixel rectangle with lower left corner at (X,Y) and with width WIDTH and height HEIGHT replaces the portion of the texture array with x indices XOFFSET through XOFFSET+WIDTH-1 , inclusive, and y indices YOFFSET through YOFFSET+HEIGHT-1 , inclusive, at the mipmap level specified by LEVEL. The pixels in the rectangle are processed exactly as if `glCopyPixels' had been called, but the process stops just before final conversion. At this point, all pixel component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array. The destination rectangle in the texture array may not include any texels outside the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect. If any of the pixels within the specified rectangle of the current `GL_READ_BUFFER' are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined. No change is made to the INTERNALFORMAT, WIDTH, HEIGHT, or BORDER parameters of the specified texture array or to texel values outside the specified subregion. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage2D' or `glCopyTexImage2D' operation. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL>LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , (XOFFSET+WIDTH,)>(W-B,) , YOFFSET<-B , or (YOFFSET+HEIGHT,)>(H-B,) , where W is the `GL_TEXTURE_WIDTH', H is the `GL_TEXTURE_HEIGHT', and B is the `GL_TEXTURE_BORDER' of the texture image being modified. Note that W and H include twice the border width. `GL_INVALID_OPERATION' is generated if `glCopyTexSubImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCopyTexSubImage3D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (zoffset GLint) (x GLint) (y GLint) (width GLsizei) (height GLsizei) -> void)) "Copy a three-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_3D' LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. ZOFFSET Specifies a texel offset in the z direction within the texture array. X Y Specify the window coordinates of the lower left corner of the rectangular region of pixels to be copied. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. `glCopyTexSubImage3D' replaces a rectangular portion of a three-dimensional texture image with pixels from the current `GL_READ_BUFFER' (rather than from main memory, as is the case for `glTexSubImage3D'). The screen-aligned pixel rectangle with lower left corner at (X,\\ Y) and with width WIDTH and height HEIGHT replaces the portion of the texture array with x indices XOFFSET through XOFFSET+WIDTH-1 , inclusive, and y indices YOFFSET through YOFFSET+HEIGHT-1 , inclusive, at z index ZOFFSET and at the mipmap level specified by LEVEL. The pixels in the rectangle are processed exactly as if `glCopyPixels' had been called, but the process stops just before final conversion. At this point, all pixel component values are clamped to the range [0,1] and then converted to the texture's internal format for storage in the texel array. The destination rectangle in the texture array may not include any texels outside the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect. If any of the pixels within the specified rectangle of the current `GL_READ_BUFFER' are outside the read window associated with the current rendering context, then the values obtained for those pixels are undefined. No change is made to the INTERNALFORMAT, WIDTH, HEIGHT, DEPTH, or BORDER parameters of the specified texture array or to texel values outside the specified subregion. `GL_INVALID_ENUM' is generated if /TARGET is not `GL_TEXTURE_3D'. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage3D' operation. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL>LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_3D_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , (XOFFSET+WIDTH,)>(W-B,) , YOFFSET<-B , (YOFFSET+HEIGHT,)>(H-B,) , ZOFFSET<-B , or (ZOFFSET+1,)>(D-B,) , where W is the `GL_TEXTURE_WIDTH', H is the `GL_TEXTURE_HEIGHT', D is the `GL_TEXTURE_DEPTH', and B is the `GL_TEXTURE_BORDER' of the texture image being modified. Note that W , H , and D include twice the border width. `GL_INVALID_OPERATION' is generated if `glCopyTexSubImage3D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCreateProgram -> GLuint)) "Creates a program object. `glCreateProgram' creates an empty program object and returns a non-zero value by which it can be referenced. A program object is an object to which shader objects can be attached. This provides a mechanism to specify the shader objects that will be linked to create a program. It also provides a means for checking the compatibility of the shaders that will be used to create a program (for instance, checking the compatibility between a vertex shader and a fragment shader). When no longer needed as part of a program object, shader objects can be detached. One or more executables are created in a program object by successfully attaching shader objects to it with `glAttachShader', successfully compiling the shader objects with `glCompileShader', and successfully linking the program object with `glLinkProgram'. These executables are made part of current state when `glUseProgram' is called. Program objects can be deleted by calling `glDeleteProgram'. The memory associated with the program object will be deleted when it is no longer part of current rendering state for any context. This function returns 0 if an error occurs creating the program object. `GL_INVALID_OPERATION' is generated if `glCreateProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCreateShader (shaderType GLenum) -> GLuint)) "Creates a shader object. SHADERTYPE Specifies the type of shader to be created. Must be either `GL_VERTEX_SHADER' or `GL_FRAGMENT_SHADER'. `glCreateShader' creates an empty shader object and returns a non-zero value by which it can be referenced. A shader object is used to maintain the source code strings that define a shader. SHADERTYPE indicates the type of shader to be created. Two types of shaders are supported. A shader of type `GL_VERTEX_SHADER' is a shader that is intended to run on the programmable vertex processor and replace the fixed functionality vertex processing in OpenGL. A shader of type `GL_FRAGMENT_SHADER' is a shader that is intended to run on the programmable fragment processor and replace the fixed functionality fragment processing in OpenGL. When created, a shader object's `GL_SHADER_TYPE' parameter is set to either `GL_VERTEX_SHADER' or `GL_FRAGMENT_SHADER', depending on the value of SHADERTYPE. This function returns 0 if an error occurs creating the shader object. `GL_INVALID_ENUM' is generated if SHADERTYPE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glCreateShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glCullFace (mode GLenum) -> void)) "Specify whether front- or back-facing facets can be culled. MODE Specifies whether front- or back-facing facets are candidates for culling. Symbolic constants `GL_FRONT', `GL_BACK', and `GL_FRONT_AND_BACK' are accepted. The initial value is `GL_BACK'. `glCullFace' specifies whether front- or back-facing facets are culled (as specified by MODE) when facet culling is enabled. Facet culling is initially disabled. To enable and disable facet culling, call the `glEnable' and `glDisable' commands with the argument `GL_CULL_FACE'. Facets include triangles, quadrilaterals, polygons, and rectangles. `glFrontFace' specifies which of the clockwise and counterclockwise facets are front-facing and back-facing. See `glFrontFace'. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glCullFace' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteBuffers (n GLsizei) (buffers const-GLuint-*) -> void)) "Delete named buffer objects. N Specifies the number of buffer objects to be deleted. BUFFERS Specifies an array of buffer objects to be deleted. `glDeleteBuffers' deletes N buffer objects named by the elements of the array BUFFERS. After a buffer object is deleted, it has no contents, and its name is free for reuse (for example by `glGenBuffers'). If a buffer object that is currently bound is deleted, the binding reverts to 0 (the absence of any buffer object, which reverts to client memory usage). `glDeleteBuffers' silently ignores 0's and names that do not correspond to existing buffer objects. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glDeleteBuffers' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteLists (list GLuint) (range GLsizei) -> void)) "Delete a contiguous group of display lists. LIST Specifies the integer name of the first display list to delete. RANGE Specifies the number of display lists to delete. `glDeleteLists' causes a contiguous group of display lists to be deleted. LIST is the name of the first display list to be deleted, and RANGE is the number of display lists to delete. All display lists D with LIST<=D<=LIST+RANGE-1 are deleted. All storage locations allocated to the specified display lists are freed, and the names are available for reuse at a later time. Names within the range that do not have an associated display list are ignored. If RANGE is 0, nothing happens. `GL_INVALID_VALUE' is generated if RANGE is negative. `GL_INVALID_OPERATION' is generated if `glDeleteLists' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteProgram (program GLuint) -> void)) "Deletes a program object. PROGRAM Specifies the program object to be deleted. `glDeleteProgram' frees the memory and invalidates the name associated with the program object specified by PROGRAM. This command effectively undoes the effects of a call to `glCreateProgram'. If a program object is in use as part of current rendering state, it will be flagged for deletion, but it will not be deleted until it is no longer part of current state for any rendering context. If a program object to be deleted has shader objects attached to it, those shader objects will be automatically detached but not deleted unless they have already been flagged for deletion by a previous call to `glDeleteShader'. A value of 0 for PROGRAM will be silently ignored. To determine whether a program object has been flagged for deletion, call `glGetProgram' with arguments PROGRAM and `GL_DELETE_STATUS'. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if `glDeleteProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteQueries (n GLsizei) (ids const-GLuint-*) -> void)) "Delete named query objects. N Specifies the number of query objects to be deleted. IDS Specifies an array of query objects to be deleted. `glDeleteQueries' deletes N query objects named by the elements of the array IDS. After a query object is deleted, it has no contents, and its name is free for reuse (for example by `glGenQueries'). `glDeleteQueries' silently ignores 0's and names that do not correspond to existing query objects. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glDeleteQueries' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteShader (shader GLuint) -> void)) "Deletes a shader object. SHADER Specifies the shader object to be deleted. `glDeleteShader' frees the memory and invalidates the name associated with the shader object specified by SHADER. This command effectively undoes the effects of a call to `glCreateShader'. If a shader object to be deleted is attached to a program object, it will be flagged for deletion, but it will not be deleted until it is no longer attached to any program object, for any rendering context (i.e., it must be detached from wherever it was attached before it will be deleted). A value of 0 for SHADER will be silently ignored. To determine whether an object has been flagged for deletion, call `glGetShader' with arguments SHADER and `GL_DELETE_STATUS'. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if `glDeleteShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDeleteTextures (n GLsizei) (textures const-GLuint-*) -> void)) "Delete named textures. N Specifies the number of textures to be deleted. TEXTURES Specifies an array of textures to be deleted. `glDeleteTextures' deletes N textures named by the elements of the array TEXTURES. After a texture is deleted, it has no contents or dimensionality, and its name is free for reuse (for example by `glGenTextures'). If a texture that is currently bound is deleted, the binding reverts to 0 (the default texture). `glDeleteTextures' silently ignores 0's and names that do not correspond to existing textures. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glDeleteTextures' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDepthFunc (func GLenum) -> void)) "Specify the value used for depth buffer comparisons. FUNC Specifies the depth comparison function. Symbolic constants `GL_NEVER', `GL_LESS', `GL_EQUAL', `GL_LEQUAL', `GL_GREATER', `GL_NOTEQUAL', `GL_GEQUAL', and `GL_ALWAYS' are accepted. The initial value is `GL_LESS'. `glDepthFunc' specifies the function used to compare each incoming pixel depth value with the depth value present in the depth buffer. The comparison is performed only if depth testing is enabled. (See `glEnable' and `glDisable' of `GL_DEPTH_TEST'.) FUNC specifies the conditions under which the pixel will be drawn. The comparison functions are as follows: `GL_NEVER' Never passes. `GL_LESS' Passes if the incoming depth value is less than the stored depth value. `GL_EQUAL' Passes if the incoming depth value is equal to the stored depth value. `GL_LEQUAL' Passes if the incoming depth value is less than or equal to the stored depth value. `GL_GREATER' Passes if the incoming depth value is greater than the stored depth value. `GL_NOTEQUAL' Passes if the incoming depth value is not equal to the stored depth value. `GL_GEQUAL' Passes if the incoming depth value is greater than or equal to the stored depth value. `GL_ALWAYS' Always passes. The initial value of FUNC is `GL_LESS'. Initially, depth testing is disabled. If depth testing is disabled or if no depth buffer exists, it is as if the depth test always passes. `GL_INVALID_ENUM' is generated if FUNC is not an accepted value. `GL_INVALID_OPERATION' is generated if `glDepthFunc' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDepthMask (flag GLboolean) -> void)) "Enable or disable writing into the depth buffer. FLAG Specifies whether the depth buffer is enabled for writing. If FLAG is `GL_FALSE', depth buffer writing is disabled. Otherwise, it is enabled. Initially, depth buffer writing is enabled. `glDepthMask' specifies whether the depth buffer is enabled for writing. If FLAG is `GL_FALSE', depth buffer writing is disabled. Otherwise, it is enabled. Initially, depth buffer writing is enabled. `GL_INVALID_OPERATION' is generated if `glDepthMask' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDepthRange (nearVal GLclampd) (farVal GLclampd) -> void)) "Specify mapping of depth values from normalized device coordinates to window coordinates. NEARVAL Specifies the mapping of the near clipping plane to window coordinates. The initial value is 0. FARVAL Specifies the mapping of the far clipping plane to window coordinates. The initial value is 1. After clipping and division by W, depth coordinates range from -1 to 1, corresponding to the near and far clipping planes. `glDepthRange' specifies a linear mapping of the normalized depth coordinates in this range to window depth coordinates. Regardless of the actual depth buffer implementation, window coordinate depth values are treated as though they range from 0 through 1 (like color components). Thus, the values accepted by `glDepthRange' are both clamped to this range before they are accepted. The setting of (0,1) maps the near plane to 0 and the far plane to 1. With this mapping, the depth buffer range is fully utilized. `GL_INVALID_OPERATION' is generated if `glDepthRange' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDetachShader (program GLuint) (shader GLuint) -> void)) "Detaches a shader object from a program object to which it is attached. PROGRAM Specifies the program object from which to detach the shader object. SHADER Specifies the shader object to be detached. `glDetachShader' detaches the shader object specified by SHADER from the program object specified by PROGRAM. This command can be used to undo the effect of the command `glAttachShader'. If SHADER has already been flagged for deletion by a call to `glDeleteShader' and it is not attached to any other program object, it will be deleted after it has been detached. `GL_INVALID_VALUE' is generated if either PROGRAM or SHADER is a value that was not generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_OPERATION' is generated if SHADER is not attached to PROGRAM. `GL_INVALID_OPERATION' is generated if `glDetachShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDrawArrays (mode GLenum) (first GLint) (count GLsizei) -> void)) "Render primitives from array data. MODE Specifies what kind of primitives to render. Symbolic constants `GL_POINTS', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_LINES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_TRIANGLES', `GL_QUAD_STRIP', `GL_QUADS', and `GL_POLYGON' are accepted. FIRST Specifies the starting index in the enabled arrays. COUNT Specifies the number of indices to be rendered. `glDrawArrays' specifies multiple geometric primitives with very few subroutine calls. Instead of calling a GL procedure to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and colors and use them to construct a sequence of primitives with a single call to `glDrawArrays'. When `glDrawArrays' is called, it uses COUNT sequential elements from each enabled array to construct a sequence of geometric primitives, beginning with element FIRST. MODE specifies what kind of primitives are constructed and how the array elements construct those primitives. If `GL_VERTEX_ARRAY' is not enabled, no geometric primitives are generated. Vertex attributes that are modified by `glDrawArrays' have an unspecified value after `glDrawArrays' returns. For example, if `GL_COLOR_ARRAY' is enabled, the value of the current color is undefined after `glDrawArrays' executes. Attributes that aren't modified remain well defined. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_VALUE' is generated if COUNT is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if `glDrawArrays' is executed between the execution of `glBegin' and the corresponding `glEnd'.") (define-gl-procedures ((glDrawBuffers (n GLsizei) (bufs const-GLenum-*) -> void)) "Specifies a list of color buffers to be drawn into. N Specifies the number of buffers in BUFS. BUFS Points to an array of symbolic constants specifying the buffers into which fragment colors or data values will be written. `glDrawBuffers' defines an array of buffers into which fragment color values or fragment data will be written. If no fragment shader is active, rendering operations will generate only one fragment color per fragment and it will be written into each of the buffers specified by BUFS. If a fragment shader is active and it writes a value to the output variable `gl_FragColor', then that value will be written into each of the buffers specified by BUFS. If a fragment shader is active and it writes a value to one or more elements of the output array variable `gl_FragData[]', then the value of `gl_FragData[0] ' will be written into the first buffer specified by BUFS, the value of `gl_FragData[1] ' will be written into the second buffer specified by BUFS, and so on up to `gl_FragData[n-1]'. The draw buffer used for `gl_FragData[n]' and beyond is implicitly set to be `GL_NONE'. The symbolic constants contained in BUFS may be any of the following: `GL_NONE' The fragment color/data value is not written into any color buffer. `GL_FRONT_LEFT' The fragment color/data value is written into the front left color buffer. `GL_FRONT_RIGHT' The fragment color/data value is written into the front right color buffer. `GL_BACK_LEFT' The fragment color/data value is written into the back left color buffer. `GL_BACK_RIGHT' The fragment color/data value is written into the back right color buffer. `GL_AUXi' The fragment color/data value is written into auxiliary buffer `i'. Except for `GL_NONE', the preceding symbolic constants may not appear more than once in BUFS. The maximum number of draw buffers supported is implementation dependent and can be queried by calling `glGet' with the argument `GL_MAX_DRAW_BUFFERS'. The number of auxiliary buffers can be queried by calling `glGet' with the argument `GL_AUX_BUFFERS'. `GL_INVALID_ENUM' is generated if one of the values in BUFS is not an accepted value. `GL_INVALID_ENUM' is generated if N is less than 0. `GL_INVALID_OPERATION' is generated if a symbolic constant other than `GL_NONE' appears more than once in BUFS. `GL_INVALID_OPERATION' is generated if any of the entries in BUFS (other than `GL_NONE' ) indicates a color buffer that does not exist in the current GL context. `GL_INVALID_VALUE' is generated if N is greater than `GL_MAX_DRAW_BUFFERS'. `GL_INVALID_OPERATION' is generated if `glDrawBuffers' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDrawBuffer (mode GLenum) -> void)) "Specify which color buffers are to be drawn into. MODE Specifies up to four color buffers to be drawn into. Symbolic constants `GL_NONE', `GL_FRONT_LEFT', `GL_FRONT_RIGHT', `GL_BACK_LEFT', `GL_BACK_RIGHT', `GL_FRONT', `GL_BACK', `GL_LEFT', `GL_RIGHT', `GL_FRONT_AND_BACK', and `GL_AUX'I, where I is between 0 and the value of `GL_AUX_BUFFERS' minus 1, are accepted. (`GL_AUX_BUFFERS' is not the upper limit; use `glGet' to query the number of available aux buffers.) The initial value is `GL_FRONT' for single-buffered contexts, and `GL_BACK' for double-buffered contexts. When colors are written to the frame buffer, they are written into the color buffers specified by `glDrawBuffer'. The specifications are as follows: `GL_NONE' No color buffers are written. `GL_FRONT_LEFT' Only the front left color buffer is written. `GL_FRONT_RIGHT' Only the front right color buffer is written. `GL_BACK_LEFT' Only the back left color buffer is written. `GL_BACK_RIGHT' Only the back right color buffer is written. `GL_FRONT' Only the front left and front right color buffers are written. If there is no front right color buffer, only the front left color buffer is written. `GL_BACK' Only the back left and back right color buffers are written. If there is no back right color buffer, only the back left color buffer is written. `GL_LEFT' Only the front left and back left color buffers are written. If there is no back left color buffer, only the front left color buffer is written. `GL_RIGHT' Only the front right and back right color buffers are written. If there is no back right color buffer, only the front right color buffer is written. `GL_FRONT_AND_BACK' All the front and back color buffers (front left, front right, back left, back right) are written. If there are no back color buffers, only the front left and front right color buffers are written. If there are no right color buffers, only the front left and back left color buffers are written. If there are no right or back color buffers, only the front left color buffer is written. `GL_AUX'I Only auxiliary color buffer I is written. If more than one color buffer is selected for drawing, then blending or logical operations are computed and applied independently for each color buffer and can produce different results in each buffer. Monoscopic contexts include only LEFT buffers, and stereoscopic contexts include both LEFT and RIGHT buffers. Likewise, single-buffered contexts include only FRONT buffers, and double-buffered contexts include both FRONT and BACK buffers. The context is selected at GL initialization. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if none of the buffers indicated by MODE exists. `GL_INVALID_OPERATION' is generated if `glDrawBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDrawElements (mode GLenum) (count GLsizei) (type GLenum) (indices const-GLvoid-*) -> void)) "Render primitives from array data. MODE Specifies what kind of primitives to render. Symbolic constants `GL_POINTS', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_LINES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_TRIANGLES', `GL_QUAD_STRIP', `GL_QUADS', and `GL_POLYGON' are accepted. COUNT Specifies the number of elements to be rendered. TYPE Specifies the type of the values in INDICES. Must be one of `GL_UNSIGNED_BYTE', `GL_UNSIGNED_SHORT', or `GL_UNSIGNED_INT'. INDICES Specifies a pointer to the location where the indices are stored. `glDrawElements' specifies multiple geometric primitives with very few subroutine calls. Instead of calling a GL function to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and so on, and use them to construct a sequence of primitives with a single call to `glDrawElements'. When `glDrawElements' is called, it uses COUNT sequential elements from an enabled array, starting at INDICES to construct a sequence of geometric primitives. MODE specifies what kind of primitives are constructed and how the array elements construct these primitives. If more than one array is enabled, each is used. If `GL_VERTEX_ARRAY' is not enabled, no geometric primitives are constructed. Vertex attributes that are modified by `glDrawElements' have an unspecified value after `glDrawElements' returns. For example, if `GL_COLOR_ARRAY' is enabled, the value of the current color is undefined after `glDrawElements' executes. Attributes that aren't modified maintain their previous values. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_VALUE' is generated if COUNT is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if `glDrawElements' is executed between the execution of `glBegin' and the corresponding `glEnd'.") (define-gl-procedures ((glDrawPixels (width GLsizei) (height GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Write a block of pixels to the frame buffer. WIDTH HEIGHT Specify the dimensions of the pixel rectangle to be written into the frame buffer. FORMAT Specifies the format of the pixel data. Symbolic constants `GL_COLOR_INDEX', `GL_STENCIL_INDEX', `GL_DEPTH_COMPONENT', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA' are accepted. TYPE Specifies the data type for DATA. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. DATA Specifies a pointer to the pixel data. `glDrawPixels' reads pixel data from memory and writes it into the frame buffer relative to the current raster position, provided that the raster position is valid. Use `glRasterPos' or `glWindowPos' to set the current raster position; use `glGet' with argument `GL_CURRENT_RASTER_POSITION_VALID' to determine if the specified raster position is valid, and `glGet' with argument `GL_CURRENT_RASTER_POSITION' to query the raster position. Several parameters define the encoding of pixel data in memory and control the processing of the pixel data before it is placed in the frame buffer. These parameters are set with four commands: `glPixelStore', `glPixelTransfer', `glPixelMap', and `glPixelZoom'. This reference page describes the effects on `glDrawPixels' of many, but not all, of the parameters specified by these four commands. Data is read from DATA as a sequence of signed or unsigned bytes, signed or unsigned shorts, signed or unsigned integers, or single-precision floating-point values, depending on TYPE. When TYPE is one of `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', or `GL_FLOAT' each of these bytes, shorts, integers, or floating-point values is interpreted as one color or depth component, or one index, depending on FORMAT. When TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_INT_8_8_8_8', or `GL_UNSIGNED_INT_10_10_10_2', each unsigned value is interpreted as containing all the components for a single pixel, with the color components arranged according to FORMAT. When TYPE is one of `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8_REV', or `GL_UNSIGNED_INT_2_10_10_10_REV', each unsigned value is interpreted as containing all color components, specified by FORMAT, for a single pixel in a reversed order. Indices are always treated individually. Color components are treated as groups of one, two, three, or four values, again based on FORMAT. Both individual indices and groups of components are referred to as pixels. If TYPE is `GL_BITMAP', the data must be unsigned bytes, and FORMAT must be either `GL_COLOR_INDEX' or `GL_STENCIL_INDEX'. Each unsigned byte is treated as eight 1-bit pixels, with bit ordering determined by `GL_UNPACK_LSB_FIRST' (see `glPixelStore'). WIDTH×HEIGHT pixels are read from memory, starting at location DATA. By default, these pixels are taken from adjacent memory locations, except that after all WIDTH pixels are read, the read pointer is advanced to the next four-byte boundary. The four-byte row alignment is specified by `glPixelStore' with argument `GL_UNPACK_ALIGNMENT', and it can be set to one, two, four, or eight bytes. Other pixel store parameters specify different read pointer advancements, both before the first pixel is read and after all WIDTH pixels are read. See the `glPixelStore' reference page for details on these options. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a block of pixels is specified, DATA is treated as a byte offset into the buffer object's data store. The WIDTH×HEIGHT pixels that are read from memory are each operated on in the same way, based on the values of several parameters specified by `glPixelTransfer' and `glPixelMap'. The details of these operations, as well as the target buffer into which the pixels are drawn, are specific to the format of the pixels, as specified by FORMAT. FORMAT can assume one of 13 symbolic values: `GL_COLOR_INDEX' Each pixel is a single value, a color index. It is converted to fixed-point format, with an unspecified number of bits to the right of the binary point, regardless of the memory data type. Floating-point values convert to true fixed-point values. Signed and unsigned integer data is converted with all fraction bits set to 0. Bitmap data convert to either 0 or 1. Each fixed-point index is then shifted left by `GL_INDEX_SHIFT' bits and added to `GL_INDEX_OFFSET'. If `GL_INDEX_SHIFT' is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result. If the GL is in RGBA mode, the resulting index is converted to an RGBA pixel with the help of the `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', and `GL_PIXEL_MAP_I_TO_A' tables. If the GL is in color index mode, and if `GL_MAP_COLOR' is true, the index is replaced with the value that it references in lookup table `GL_PIXEL_MAP_I_TO_I'. Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2^B-1 , where B is the number of bits in a color index buffer. The GL then converts the resulting indices or RGBA colors to fragments by attaching the current raster position Z coordinate and texture coordinates to each pixel, then assigning X and Y window coordinates to the N th fragment such that X_N=X_R+N%WIDTH Y_N=Y_R+⌊N/WIDTH,⌋ where (X_R,Y_R) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer. `GL_STENCIL_INDEX' Each pixel is a single value, a stencil index. It is converted to fixed-point format, with an unspecified number of bits to the right of the binary point, regardless of the memory data type. Floating-point values convert to true fixed-point values. Signed and unsigned integer data is converted with all fraction bits set to 0. Bitmap data convert to either 0 or 1. Each fixed-point index is then shifted left by `GL_INDEX_SHIFT' bits, and added to `GL_INDEX_OFFSET'. If `GL_INDEX_SHIFT' is negative, the shift is to the right. In either case, zero bits fill otherwise unspecified bit locations in the result. If `GL_MAP_STENCIL' is true, the index is replaced with the value that it references in lookup table `GL_PIXEL_MAP_S_TO_S'. Whether the lookup replacement of the index is done or not, the integer part of the index is then ANDed with 2^B-1 , where B is the number of bits in the stencil buffer. The resulting stencil indices are then written to the stencil buffer such that the N th index is written to location X_N=X_R+N%WIDTH Y_N=Y_R+⌊N/WIDTH,⌋ where (X_R,Y_R) is the current raster position. Only the pixel ownership test, the scissor test, and the stencil writemask affect these write operations. `GL_DEPTH_COMPONENT' Each pixel is a single-depth component. Floating-point data is converted directly to an internal floating-point format with unspecified precision. Signed integer data is mapped linearly to the internal floating-point format such that the most positive representable integer value maps to 1.0, and the most negative representable value maps to -1.0 . Unsigned integer data is mapped similarly: the largest integer value maps to 1.0, and 0 maps to 0.0. The resulting floating-point depth value is then multiplied by `GL_DEPTH_SCALE' and added to `GL_DEPTH_BIAS'. The result is clamped to the range [0,1] . The GL then converts the resulting depth components to fragments by attaching the current raster position color or color index and texture coordinates to each pixel, then assigning X and Y window coordinates to the N th fragment such that X_N=X_R+N%WIDTH Y_N=Y_R+⌊N/WIDTH,⌋ where (X_R,Y_R) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer. `GL_RGBA' `GL_BGRA' Each pixel is a four-component group: For `GL_RGBA', the red component is first, followed by green, followed by blue, followed by alpha; for `GL_BGRA' the order is blue, green, red and then alpha. Floating-point values are converted directly to an internal floating-point format with unspecified precision. Signed integer values are mapped linearly to the internal floating-point format such that the most positive representable integer value maps to 1.0, and the most negative representable value maps to -1.0 . (Note that this mapping does not convert 0 precisely to 0.0.) Unsigned integer data is mapped similarly: The largest integer value maps to 1.0, and 0 maps to 0.0. The resulting floating-point color values are then multiplied by `GL_c_SCALE' and added to `GL_c_BIAS', where C is RED, GREEN, BLUE, and ALPHA for the respective color components. The results are clamped to the range [0,1] . If `GL_MAP_COLOR' is true, each color component is scaled by the size of lookup table `GL_PIXEL_MAP_c_TO_c', then replaced by the value that it references in that table. C is R, G, B, or A respectively. The GL then converts the resulting RGBA colors to fragments by attaching the current raster position Z coordinate and texture coordinates to each pixel, then assigning X and Y window coordinates to the N th fragment such that X_N=X_R+N%WIDTH Y_N=Y_R+⌊N/WIDTH,⌋ where (X_R,Y_R) is the current raster position. These pixel fragments are then treated just like the fragments generated by rasterizing points, lines, or polygons. Texture mapping, fog, and all the fragment operations are applied before the fragments are written to the frame buffer. `GL_RED' Each pixel is a single red component. This component is converted to the internal floating-point format in the same way the red component of an RGBA pixel is. It is then converted to an RGBA pixel with green and blue set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_GREEN' Each pixel is a single green component. This component is converted to the internal floating-point format in the same way the green component of an RGBA pixel is. It is then converted to an RGBA pixel with red and blue set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_BLUE' Each pixel is a single blue component. This component is converted to the internal floating-point format in the same way the blue component of an RGBA pixel is. It is then converted to an RGBA pixel with red and green set to 0, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_ALPHA' Each pixel is a single alpha component. This component is converted to the internal floating-point format in the same way the alpha component of an RGBA pixel is. It is then converted to an RGBA pixel with red, green, and blue set to 0. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_RGB' `GL_BGR' Each pixel is a three-component group: red first, followed by green, followed by blue; for `GL_BGR', the first component is blue, followed by green and then red. Each component is converted to the internal floating-point format in the same way the red, green, and blue components of an RGBA pixel are. The color triple is converted to an RGBA pixel with alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_LUMINANCE' Each pixel is a single luminance component. This component is converted to the internal floating-point format in the same way the red component of an RGBA pixel is. It is then converted to an RGBA pixel with red, green, and blue set to the converted luminance value, and alpha set to 1. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. `GL_LUMINANCE_ALPHA' Each pixel is a two-component group: luminance first, followed by alpha. The two components are converted to the internal floating-point format in the same way the red component of an RGBA pixel is. They are then converted to an RGBA pixel with red, green, and blue set to the converted luminance value, and alpha set to the converted alpha value. After this conversion, the pixel is treated as if it had been read as an RGBA pixel. The following table summarizes the meaning of the valid constants for the TYPE parameter: *Type* *Corresponding Type* `GL_UNSIGNED_BYTE' unsigned 8-bit integer `GL_BYTE' signed 8-bit integer `GL_BITMAP' single bits in unsigned 8-bit integers `GL_UNSIGNED_SHORT' unsigned 16-bit integer `GL_SHORT' signed 16-bit integer `GL_UNSIGNED_INT' unsigned 32-bit integer `GL_INT' 32-bit integer `GL_FLOAT' single-precision floating-point `GL_UNSIGNED_BYTE_3_3_2' unsigned 8-bit integer `GL_UNSIGNED_BYTE_2_3_3_REV' unsigned 8-bit integer with reversed component ordering `GL_UNSIGNED_SHORT_5_6_5' unsigned 16-bit integer `GL_UNSIGNED_SHORT_5_6_5_REV' unsigned 16-bit integer with reversed component ordering `GL_UNSIGNED_SHORT_4_4_4_4' unsigned 16-bit integer `GL_UNSIGNED_SHORT_4_4_4_4_REV' unsigned 16-bit integer with reversed component ordering `GL_UNSIGNED_SHORT_5_5_5_1' unsigned 16-bit integer `GL_UNSIGNED_SHORT_1_5_5_5_REV' unsigned 16-bit integer with reversed component ordering `GL_UNSIGNED_INT_8_8_8_8' unsigned 32-bit integer `GL_UNSIGNED_INT_8_8_8_8_REV' unsigned 32-bit integer with reversed component ordering `GL_UNSIGNED_INT_10_10_10_2' unsigned 32-bit integer `GL_UNSIGNED_INT_2_10_10_10_REV' unsigned 32-bit integer with reversed component ordering The rasterization described so far assumes pixel zoom factors of 1. If `glPixelZoom' is used to change the X and Y pixel zoom factors, pixels are converted to fragments as follows. If (X_R,Y_R) is the current raster position, and a given pixel is in the N th column and M th row of the pixel rectangle, then fragments are generated for pixels whose centers are in the rectangle with corners at (X_R+ZOOM_X,\u2062N,Y_R+ZOOM_Y,\u2062M) (X_R+ZOOM_X,\u2061(N+1,),Y_R+ZOOM_Y,\u2061(M+1,)) where ZOOM_X is the value of `GL_ZOOM_X' and ZOOM_Y is the value of `GL_ZOOM_Y'. `GL_INVALID_ENUM' is generated if FORMAT or TYPE is not one of the accepted values. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not either `GL_COLOR_INDEX' or `GL_STENCIL_INDEX'. `GL_INVALID_VALUE' is generated if either WIDTH or HEIGHT is negative. `GL_INVALID_OPERATION' is generated if FORMAT is `GL_STENCIL_INDEX' and there is no stencil buffer. `GL_INVALID_OPERATION' is generated if FORMAT is `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_RGBA', `GL_BGR', `GL_BGRA', `GL_LUMINANCE', or `GL_LUMINANCE_ALPHA', and the GL is in color index mode. `GL_INVALID_OPERATION' is generated if FORMAT is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if FORMAT is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glDrawPixels' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glDrawRangeElements (mode GLenum) (start GLuint) (end GLuint) (count GLsizei) (type GLenum) (indices const-GLvoid-*) -> void)) "Render primitives from array data. MODE Specifies what kind of primitives to render. Symbolic constants `GL_POINTS', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_LINES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_TRIANGLES', `GL_QUAD_STRIP', `GL_QUADS', and `GL_POLYGON' are accepted. START Specifies the minimum array index contained in INDICES. END Specifies the maximum array index contained in INDICES. COUNT Specifies the number of elements to be rendered. TYPE Specifies the type of the values in INDICES. Must be one of `GL_UNSIGNED_BYTE', `GL_UNSIGNED_SHORT', or `GL_UNSIGNED_INT'. INDICES Specifies a pointer to the location where the indices are stored. `glDrawRangeElements' is a restricted form of `glDrawElements'. MODE, START, END, and COUNT match the corresponding arguments to `glDrawElements', with the additional constraint that all values in the arrays COUNT must lie between START and END, inclusive. Implementations denote recommended maximum amounts of vertex and index data, which may be queried by calling `glGet' with argument `GL_MAX_ELEMENTS_VERTICES' and `GL_MAX_ELEMENTS_INDICES'. If END-START+1 is greater than the value of `GL_MAX_ELEMENTS_VERTICES', or if COUNT is greater than the value of `GL_MAX_ELEMENTS_INDICES', then the call may operate at reduced performance. There is no requirement that all vertices in the range [START,END] be referenced. However, the implementation may partially process unused vertices, reducing performance from what could be achieved with an optimal index set. When `glDrawRangeElements' is called, it uses COUNT sequential elements from an enabled array, starting at START to construct a sequence of geometric primitives. MODE specifies what kind of primitives are constructed, and how the array elements construct these primitives. If more than one array is enabled, each is used. If `GL_VERTEX_ARRAY' is not enabled, no geometric primitives are constructed. Vertex attributes that are modified by `glDrawRangeElements' have an unspecified value after `glDrawRangeElements' returns. For example, if `GL_COLOR_ARRAY' is enabled, the value of the current color is undefined after `glDrawRangeElements' executes. Attributes that aren't modified maintain their previous values. It is an error for indices to lie outside the range [START,END] , but implementations may not check for this situation. Such indices cause implementation-dependent behavior. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_VALUE' is generated if COUNT is negative. `GL_INVALID_VALUE' is generated if END void)) "Define an array of edge flags. STRIDE Specifies the byte offset between consecutive edge flags. If STRIDE is 0, the edge flags are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first edge flag in the array. The initial value is 0. `glEdgeFlagPointer' specifies the location and data format of an array of boolean edge flags to use when rendering. STRIDE specifies the byte stride from one edge flag to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while an edge flag array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as edge flag vertex array client-side state (`GL_EDGE_FLAG_ARRAY_BUFFER_BINDING'). When an edge flag array is specified, STRIDE and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the edge flag array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_EDGE_FLAG_ARRAY'. If enabled, the edge flag array is used when `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', `glDrawRangeElements', or `glArrayElement' is called. `GL_INVALID_ENUM' is generated if STRIDE is negative.") (define-gl-procedures ((glEdgeFlag (flag GLboolean) -> void)) "Flag edges as either boundary or nonboundary. FLAG Specifies the current edge flag value, either `GL_TRUE' or `GL_FALSE'. The initial value is `GL_TRUE'. Each vertex of a polygon, separate triangle, or separate quadrilateral specified between a `glBegin'/`glEnd' pair is marked as the start of either a boundary or nonboundary edge. If the current edge flag is true when the vertex is specified, the vertex is marked as the start of a boundary edge. Otherwise, the vertex is marked as the start of a nonboundary edge. `glEdgeFlag' sets the edge flag bit to `GL_TRUE' if FLAG is `GL_TRUE' and to `GL_FALSE' otherwise. The vertices of connected triangles and connected quadrilaterals are always marked as boundary, regardless of the value of the edge flag. Boundary and nonboundary edge flags on vertices are significant only if `GL_POLYGON_MODE' is set to `GL_POINT' or `GL_LINE'. See `glPolygonMode'.") (define-gl-procedures ((glEnableClientState (cap GLenum) -> void) (glDisableClientState (cap GLenum) -> void)) "Enable or disable client-side capability. CAP Specifies the capability to enable. Symbolic constants `GL_COLOR_ARRAY', `GL_EDGE_FLAG_ARRAY', `GL_FOG_COORD_ARRAY', `GL_INDEX_ARRAY', `GL_NORMAL_ARRAY', `GL_SECONDARY_COLOR_ARRAY', `GL_TEXTURE_COORD_ARRAY', and `GL_VERTEX_ARRAY' are accepted. `glEnableClientState' and `glDisableClientState' enable or disable individual client-side capabilities. By default, all client-side capabilities are disabled. Both `glEnableClientState' and `glDisableClientState' take a single argument, CAP, which can assume one of the following values: `GL_COLOR_ARRAY' If enabled, the color array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glColorPointer'. `GL_EDGE_FLAG_ARRAY' If enabled, the edge flag array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glEdgeFlagPointer'. `GL_FOG_COORD_ARRAY' If enabled, the fog coordinate array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glFogCoordPointer'. `GL_INDEX_ARRAY' If enabled, the index array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glIndexPointer'. `GL_NORMAL_ARRAY' If enabled, the normal array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glNormalPointer'. `GL_SECONDARY_COLOR_ARRAY' If enabled, the secondary color array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glColorPointer'. `GL_TEXTURE_COORD_ARRAY' If enabled, the texture coordinate array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glTexCoordPointer'. `GL_VERTEX_ARRAY' If enabled, the vertex array is enabled for writing and used during rendering when `glArrayElement', `glDrawArrays', `glDrawElements', `glDrawRangeElements'`glMultiDrawArrays', or `glMultiDrawElements' is called. See `glVertexPointer'. `GL_INVALID_ENUM' is generated if CAP is not an accepted value. `glEnableClientState' is not allowed between the execution of `glBegin' and the corresponding `glEnd', but an error may or may not be generated. If no error is generated, the behavior is undefined.") (define-gl-procedures ((glEnableVertexAttribArray (index GLuint) -> void) (glDisableVertexAttribArray (index GLuint) -> void)) "Enable or disable a generic vertex attribute array. INDEX Specifies the index of the generic vertex attribute to be enabled or disabled. `glEnableVertexAttribArray' enables the generic vertex attribute array specified by INDEX. `glDisableVertexAttribArray' disables the generic vertex attribute array specified by INDEX. By default, all client-side capabilities are disabled, including all generic vertex attribute arrays. If enabled, the values in the generic vertex attribute array will be accessed and used for rendering when calls are made to vertex array commands such as `glDrawArrays', `glDrawElements', `glDrawRangeElements', `glArrayElement', `glMultiDrawElements', or `glMultiDrawArrays'. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'. `GL_INVALID_OPERATION' is generated if either `glEnableVertexAttribArray ' or `glDisableVertexAttribArray ' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glEnable (cap GLenum) -> void) (glDisable (cap GLenum) -> void)) "Enable or disable server-side GL capabilities. CAP Specifies a symbolic constant indicating a GL capability. `glEnable' and `glDisable' enable and disable various capabilities. Use `glIsEnabled' or `glGet' to determine the current setting of any capability. The initial value for each capability with the exception of `GL_DITHER' and `GL_MULTISAMPLE' is `GL_FALSE'. The initial value for `GL_DITHER' and `GL_MULTISAMPLE' is `GL_TRUE'. Both `glEnable' and `glDisable' take a single argument, CAP, which can assume one of the following values: `GL_ALPHA_TEST' If enabled, do alpha testing. See `glAlphaFunc'. `GL_AUTO_NORMAL' If enabled, generate normal vectors when either `GL_MAP2_VERTEX_3' or `GL_MAP2_VERTEX_4' is used to generate vertices. See `glMap2'. `GL_BLEND' If enabled, blend the computed fragment color values with the values in the color buffers. See `glBlendFunc'. `GL_CLIP_PLANE'I If enabled, clip geometry against user-defined clipping plane I. See `glClipPlane'. `GL_COLOR_LOGIC_OP' If enabled, apply the currently selected logical operation to the computed fragment color and color buffer values. See `glLogicOp'. `GL_COLOR_MATERIAL' If enabled, have one or more material parameters track the current color. See `glColorMaterial'. `GL_COLOR_SUM' If enabled and no fragment shader is active, add the secondary color value to the computed fragment color. See `glSecondaryColor'. `GL_COLOR_TABLE' If enabled, perform a color table lookup on the incoming RGBA color values. See `glColorTable'. `GL_CONVOLUTION_1D' If enabled, perform a 1D convolution operation on incoming RGBA color values. See `glConvolutionFilter1D'. `GL_CONVOLUTION_2D' If enabled, perform a 2D convolution operation on incoming RGBA color values. See `glConvolutionFilter2D'. `GL_CULL_FACE' If enabled, cull polygons based on their winding in window coordinates. See `glCullFace'. `GL_DEPTH_TEST' If enabled, do depth comparisons and update the depth buffer. Note that even if the depth buffer exists and the depth mask is non-zero, the depth buffer is not updated if the depth test is disabled. See `glDepthFunc' and `glDepthRange'. `GL_DITHER' If enabled, dither color components or indices before they are written to the color buffer. `GL_FOG' If enabled and no fragment shader is active, blend a fog color into the post-texturing color. See `glFog'. `GL_HISTOGRAM' If enabled, histogram incoming RGBA color values. See `glHistogram'. `GL_INDEX_LOGIC_OP' If enabled, apply the currently selected logical operation to the incoming index and color buffer indices. See `glLogicOp'. `GL_LIGHT'I If enabled, include light I in the evaluation of the lighting equation. See `glLightModel' and `glLight'. `GL_LIGHTING' If enabled and no vertex shader is active, use the current lighting parameters to compute the vertex color or index. Otherwise, simply associate the current color or index with each vertex. See `glMaterial', `glLightModel', and `glLight'. `GL_LINE_SMOOTH' If enabled, draw lines with correct filtering. Otherwise, draw aliased lines. See `glLineWidth'. `GL_LINE_STIPPLE' If enabled, use the current line stipple pattern when drawing lines. See `glLineStipple'. `GL_MAP1_COLOR_4' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate RGBA values. See `glMap1'. `GL_MAP1_INDEX' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate color indices. See `glMap1'. `GL_MAP1_NORMAL' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate normals. See `glMap1'. `GL_MAP1_TEXTURE_COORD_1' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate S texture coordinates. See `glMap1'. `GL_MAP1_TEXTURE_COORD_2' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate S and T texture coordinates. See `glMap1'. `GL_MAP1_TEXTURE_COORD_3' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate S, T, and R texture coordinates. See `glMap1'. `GL_MAP1_TEXTURE_COORD_4' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate S, T, R, and Q texture coordinates. See `glMap1'. `GL_MAP1_VERTEX_3' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate X, Y, and Z vertex coordinates. See `glMap1'. `GL_MAP1_VERTEX_4' If enabled, calls to `glEvalCoord1', `glEvalMesh1', and `glEvalPoint1' generate homogeneous X, Y, Z, and W vertex coordinates. See `glMap1'. `GL_MAP2_COLOR_4' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate RGBA values. See `glMap2'. `GL_MAP2_INDEX' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate color indices. See `glMap2'. `GL_MAP2_NORMAL' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate normals. See `glMap2'. `GL_MAP2_TEXTURE_COORD_1' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate S texture coordinates. See `glMap2'. `GL_MAP2_TEXTURE_COORD_2' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate S and T texture coordinates. See `glMap2'. `GL_MAP2_TEXTURE_COORD_3' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate S, T, and R texture coordinates. See `glMap2'. `GL_MAP2_TEXTURE_COORD_4' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate S, T, R, and Q texture coordinates. See `glMap2'. `GL_MAP2_VERTEX_3' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate X, Y, and Z vertex coordinates. See `glMap2'. `GL_MAP2_VERTEX_4' If enabled, calls to `glEvalCoord2', `glEvalMesh2', and `glEvalPoint2' generate homogeneous X, Y, Z, and W vertex coordinates. See `glMap2'. `GL_MINMAX' If enabled, compute the minimum and maximum values of incoming RGBA color values. See `glMinmax'. `GL_MULTISAMPLE' If enabled, use multiple fragment samples in computing the final color of a pixel. See `glSampleCoverage'. `GL_NORMALIZE' If enabled and no vertex shader is active, normal vectors are normalized to unit length after transformation and before lighting. This method is generally less efficient than `GL_RESCALE_NORMAL'. See `glNormal' and `glNormalPointer'. `GL_POINT_SMOOTH' If enabled, draw points with proper filtering. Otherwise, draw aliased points. See `glPointSize'. `GL_POINT_SPRITE' If enabled, calculate texture coordinates for points based on texture environment and point parameter settings. Otherwise texture coordinates are constant across points. `GL_POLYGON_OFFSET_FILL' If enabled, and if the polygon is rendered in `GL_FILL' mode, an offset is added to depth values of a polygon's fragments before the depth comparison is performed. See `glPolygonOffset'. `GL_POLYGON_OFFSET_LINE' If enabled, and if the polygon is rendered in `GL_LINE' mode, an offset is added to depth values of a polygon's fragments before the depth comparison is performed. See `glPolygonOffset'. `GL_POLYGON_OFFSET_POINT' If enabled, an offset is added to depth values of a polygon's fragments before the depth comparison is performed, if the polygon is rendered in `GL_POINT' mode. See `glPolygonOffset'. `GL_POLYGON_SMOOTH' If enabled, draw polygons with proper filtering. Otherwise, draw aliased polygons. For correct antialiased polygons, an alpha buffer is needed and the polygons must be sorted front to back. `GL_POLYGON_STIPPLE' If enabled, use the current polygon stipple pattern when rendering polygons. See `glPolygonStipple'. `GL_POST_COLOR_MATRIX_COLOR_TABLE' If enabled, perform a color table lookup on RGBA color values after color matrix transformation. See `glColorTable'. `GL_POST_CONVOLUTION_COLOR_TABLE' If enabled, perform a color table lookup on RGBA color values after convolution. See `glColorTable'. `GL_RESCALE_NORMAL' If enabled and no vertex shader is active, normal vectors are scaled after transformation and before lighting by a factor computed from the modelview matrix. If the modelview matrix scales space uniformly, this has the effect of restoring the transformed normal to unit length. This method is generally more efficient than `GL_NORMALIZE'. See `glNormal' and `glNormalPointer'. `GL_SAMPLE_ALPHA_TO_COVERAGE' If enabled, compute a temporary coverage value where each bit is determined by the alpha value at the corresponding sample location. The temporary coverage value is then ANDed with the fragment coverage value. `GL_SAMPLE_ALPHA_TO_ONE' If enabled, each sample alpha value is replaced by the maximum representable alpha value. `GL_SAMPLE_COVERAGE' If enabled, the fragment's coverage is ANDed with the temporary coverage value. If `GL_SAMPLE_COVERAGE_INVERT' is set to `GL_TRUE', invert the coverage value. See `glSampleCoverage'. `GL_SEPARABLE_2D' If enabled, perform a two-dimensional convolution operation using a separable convolution filter on incoming RGBA color values. See `glSeparableFilter2D'. `GL_SCISSOR_TEST' If enabled, discard fragments that are outside the scissor rectangle. See `glScissor'. `GL_STENCIL_TEST' If enabled, do stencil testing and update the stencil buffer. See `glStencilFunc' and `glStencilOp'. `GL_TEXTURE_1D' If enabled and no fragment shader is active, one-dimensional texturing is performed (unless two- or three-dimensional or cube-mapped texturing is also enabled). See `glTexImage1D'. `GL_TEXTURE_2D' If enabled and no fragment shader is active, two-dimensional texturing is performed (unless three-dimensional or cube-mapped texturing is also enabled). See `glTexImage2D'. `GL_TEXTURE_3D' If enabled and no fragment shader is active, three-dimensional texturing is performed (unless cube-mapped texturing is also enabled). See `glTexImage3D'. `GL_TEXTURE_CUBE_MAP' If enabled and no fragment shader is active, cube-mapped texturing is performed. See `glTexImage2D'. `GL_TEXTURE_GEN_Q' If enabled and no vertex shader is active, the Q texture coordinate is computed using the texture generation function defined with `glTexGen'. Otherwise, the current Q texture coordinate is used. See `glTexGen'. `GL_TEXTURE_GEN_R' If enabled and no vertex shader is active, the R texture coordinate is computed using the texture generation function defined with `glTexGen'. Otherwise, the current R texture coordinate is used. See `glTexGen'. `GL_TEXTURE_GEN_S' If enabled and no vertex shader is active, the S texture coordinate is computed using the texture generation function defined with `glTexGen'. Otherwise, the current S texture coordinate is used. See `glTexGen'. `GL_TEXTURE_GEN_T' If enabled and no vertex shader is active, the T texture coordinate is computed using the texture generation function defined with `glTexGen'. Otherwise, the current T texture coordinate is used. See `glTexGen'. `GL_VERTEX_PROGRAM_POINT_SIZE' If enabled and a vertex shader is active, then the derived point size is taken from the (potentially clipped) shader builtin `gl_PointSize' and clamped to the implementation-dependent point size range. `GL_VERTEX_PROGRAM_TWO_SIDE' If enabled and a vertex shader is active, it specifies that the GL will choose between front and back colors based on the polygon's face direction of which the vertex being shaded is a part. It has no effect on points or lines. `GL_INVALID_ENUM' is generated if CAP is not one of the values listed previously. `GL_INVALID_OPERATION' is generated if `glEnable' or `glDisable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glEvalCoord1f (u GLfloat) -> void) (glEvalCoord2f (u GLfloat) (v GLfloat) -> void)) "Evaluate enabled one- and two-dimensional maps. U Specifies a value that is the domain coordinate U to the basis function defined in a previous `glMap1' or `glMap2' command. V Specifies a value that is the domain coordinate V to the basis function defined in a previous `glMap2' command. This argument is not present in a `glEvalCoord1' command. `glEvalCoord1' evaluates enabled one-dimensional maps at argument U. `glEvalCoord2' does the same for two-dimensional maps using two domain values, U and V. To define a map, call `glMap1' and `glMap2'; to enable and disable it, call `glEnable' and `glDisable'. When one of the `glEvalCoord' commands is issued, all currently enabled maps of the indicated dimension are evaluated. Then, for each enabled map, it is as if the corresponding GL command had been issued with the computed value. That is, if `GL_MAP1_INDEX' or `GL_MAP2_INDEX' is enabled, a `glIndex' command is simulated. If `GL_MAP1_COLOR_4' or `GL_MAP2_COLOR_4' is enabled, a `glColor' command is simulated. If `GL_MAP1_NORMAL' or `GL_MAP2_NORMAL' is enabled, a normal vector is produced, and if any of `GL_MAP1_TEXTURE_COORD_1', `GL_MAP1_TEXTURE_COORD_2', `GL_MAP1_TEXTURE_COORD_3', `GL_MAP1_TEXTURE_COORD_4', `GL_MAP2_TEXTURE_COORD_1', `GL_MAP2_TEXTURE_COORD_2', `GL_MAP2_TEXTURE_COORD_3', or `GL_MAP2_TEXTURE_COORD_4' is enabled, then an appropriate `glTexCoord' command is simulated. For color, color index, normal, and texture coordinates the GL uses evaluated values instead of current values for those evaluations that are enabled, and current values otherwise, However, the evaluated values do not update the current values. Thus, if `glVertex' commands are interspersed with `glEvalCoord' commands, the color, normal, and texture coordinates associated with the `glVertex' commands are not affected by the values generated by the `glEvalCoord' commands, but only by the most recent `glColor', `glIndex', `glNormal', and `glTexCoord' commands. No commands are issued for maps that are not enabled. If more than one texture evaluation is enabled for a particular dimension (for example, `GL_MAP2_TEXTURE_COORD_1' and `GL_MAP2_TEXTURE_COORD_2'), then only the evaluation of the map that produces the larger number of coordinates (in this case, `GL_MAP2_TEXTURE_COORD_2') is carried out. `GL_MAP1_VERTEX_4' overrides `GL_MAP1_VERTEX_3', and `GL_MAP2_VERTEX_4' overrides `GL_MAP2_VERTEX_3', in the same manner. If neither a three- nor a four-component vertex map is enabled for the specified dimension, the `glEvalCoord' command is ignored. If you have enabled automatic normal generation, by calling `glEnable' with argument `GL_AUTO_NORMAL', `glEvalCoord2' generates surface normals analytically, regardless of the contents or enabling of the `GL_MAP2_NORMAL' map. Let `m'=∂`p',/∂U,,×∂`p',/∂V,, Then the generated normal `n' is `n'=`m'/∥`m',∥, If automatic normal generation is disabled, the corresponding normal map `GL_MAP2_NORMAL', if enabled, is used to produce a normal. If neither automatic normal generation nor a normal map is enabled, no normal is generated for `glEvalCoord2' commands.") (define-gl-procedures ((glEvalMesh1 (mode GLenum) (i1 GLint) (i2 GLint) -> void) (glEvalMesh2 (mode GLenum) (i1 GLint) (i2 GLint) (j1 GLint) (j2 GLint) -> void)) "Compute a one- or two-dimensional grid of points or lines. MODE In `glEvalMesh1', specifies whether to compute a one-dimensional mesh of points or lines. Symbolic constants `GL_POINT' and `GL_LINE' are accepted. I1 I2 Specify the first and last integer values for grid domain variable I . `glMapGrid' and `glEvalMesh' are used in tandem to efficiently generate and evaluate a series of evenly-spaced map domain values. `glEvalMesh' steps through the integer domain of a one- or two-dimensional grid, whose range is the domain of the evaluation maps specified by `glMap1' and `glMap2'. MODE determines whether the resulting vertices are connected as points, lines, or filled polygons. In the one-dimensional case, `glEvalMesh1', the mesh is generated as if the following code fragment were executed: where glBegin( TYPE ); for ( i = I1; i <= I2; i += 1 ) glEvalCoord1( i·ΔU+U_1 ); glEnd(); ΔU=(U_2-U_1,)/N and N , U_1 , and U_2 are the arguments to the most recent `glMapGrid1' command. TYPE is `GL_POINTS' if MODE is `GL_POINT', or `GL_LINES' if MODE is `GL_LINE'. The one absolute numeric requirement is that if I=N , then the value computed from I·ΔU+U_1 is exactly U_2 . In the two-dimensional case, `glEvalMesh2', let .cp ΔU=(U_2-U_1,)/N ΔV=(V_2-V_1,)/M where N , U_1 , U_2 , M , V_1 , and V_2 are the arguments to the most recent `glMapGrid2' command. Then, if MODE is `GL_FILL', the `glEvalMesh2' command is equivalent to: for ( j = J1; j < J2; j += 1 ) { glBegin( GL_QUAD_STRIP ); for ( i = I1; i <= I2; i += 1 ) { glEvalCoord2( i·ΔU+U_1,j·ΔV+V_1 ); glEvalCoord2( i·ΔU+U_1,(j+1,)·ΔV+V_1 ); } glEnd(); } If MODE is `GL_LINE', then a call to `glEvalMesh2' is equivalent to: for ( j = J1; j <= J2; j += 1 ) { glBegin( GL_LINE_STRIP ); for ( i = I1; i <= I2; i += 1 ) glEvalCoord2( i·ΔU+U_1,j·ΔV+V_1 ); glEnd(); } for ( i = I1; i <= I2; i += 1 ) { glBegin( GL_LINE_STRIP ); for ( j = J1; j <= J1; j += 1 ) glEvalCoord2( i·ΔU+U_1,j·ΔV+V_1 ); glEnd(); } And finally, if MODE is `GL_POINT', then a call to `glEvalMesh2' is equivalent to: glBegin( GL_POINTS ); for ( j = J1; j <= J2; j += 1 ) for ( i = I1; i <= I2; i += 1 ) glEvalCoord2( i·ΔU+U_1,j·ΔV+V_1 ); glEnd(); In all three cases, the only absolute numeric requirements are that if I=N , then the value computed from I·ΔU+U_1 is exactly U_2 , and if J=M , then the value computed from J·ΔV+V_1 is exactly V_2 . `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glEvalMesh' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glEvalPoint1 (i GLint) -> void) (glEvalPoint2 (i GLint) (j GLint) -> void)) "Generate and evaluate a single point in a mesh. I Specifies the integer value for grid domain variable I . J Specifies the integer value for grid domain variable J (`glEvalPoint2' only). `glMapGrid' and `glEvalMesh' are used in tandem to efficiently generate and evaluate a series of evenly spaced map domain values. `glEvalPoint' can be used to evaluate a single grid point in the same gridspace that is traversed by `glEvalMesh'. Calling `glEvalPoint1' is equivalent to calling where ΔU=(U_2-U_1,)/N glEvalCoord1( i·ΔU+U_1 ); and N , U_1 , and U_2 are the arguments to the most recent `glMapGrid1' command. The one absolute numeric requirement is that if I=N , then the value computed from I·ΔU+U_1 is exactly U_2 . In the two-dimensional case, `glEvalPoint2', let ΔU=(U_2-U_1,)/N ΔV=(V_2-V_1,)/M where N , U_1 , U_2 , M , V_1 , and V_2 are the arguments to the most recent `glMapGrid2' command. Then the `glEvalPoint2' command is equivalent to calling The only absolute numeric requirements are that if I=N , then the value computed from I·ΔU+U_1 is exactly U_2 , and if J=M , then the value computed from J·ΔV+V_1 is exactly V_2 . glEvalCoord2( i·ΔU+U_1,j·ΔV+V_1 );") (define-gl-procedures ((glFeedbackBuffer (size GLsizei) (type GLenum) (buffer GLfloat-*) -> void)) "Controls feedback mode. SIZE Specifies the maximum number of values that can be written into BUFFER. TYPE Specifies a symbolic constant that describes the information that will be returned for each vertex. `GL_2D', `GL_3D', `GL_3D_COLOR', `GL_3D_COLOR_TEXTURE', and `GL_4D_COLOR_TEXTURE' are accepted. BUFFER Returns the feedback data. The `glFeedbackBuffer' function controls feedback. Feedback, like selection, is a GL mode. The mode is selected by calling `glRenderMode' with `GL_FEEDBACK'. When the GL is in feedback mode, no pixels are produced by rasterization. Instead, information about primitives that would have been rasterized is fed back to the application using the GL. `glFeedbackBuffer' has three arguments: BUFFER is a pointer to an array of floating-point values into which feedback information is placed. SIZE indicates the size of the array. TYPE is a symbolic constant describing the information that is fed back for each vertex. `glFeedbackBuffer' must be issued before feedback mode is enabled (by calling `glRenderMode' with argument `GL_FEEDBACK'). Setting `GL_FEEDBACK' without establishing the feedback buffer, or calling `glFeedbackBuffer' while the GL is in feedback mode, is an error. When `glRenderMode' is called while in feedback mode, it returns the number of entries placed in the feedback array and resets the feedback array pointer to the base of the feedback buffer. The returned value never exceeds SIZE. If the feedback data required more room than was available in BUFFER, `glRenderMode' returns a negative value. To take the GL out of feedback mode, call `glRenderMode' with a parameter value other than `GL_FEEDBACK'. While in feedback mode, each primitive, bitmap, or pixel rectangle that would be rasterized generates a block of values that are copied into the feedback array. If doing so would cause the number of entries to exceed the maximum, the block is partially written so as to fill the array (if there is any room left at all), and an overflow flag is set. Each block begins with a code indicating the primitive type, followed by values that describe the primitive's vertices and associated data. Entries are also written for bitmaps and pixel rectangles. Feedback occurs after polygon culling and `glPolygonMode' interpretation of polygons has taken place, so polygons that are culled are not returned in the feedback buffer. It can also occur after polygons with more than three edges are broken up into triangles, if the GL implementation renders polygons by performing this decomposition. The `glPassThrough' command can be used to insert a marker into the feedback buffer. See `glPassThrough'. Following is the grammar for the blocks of values written into the feedback buffer. Each primitive is indicated with a unique identifying value followed by some number of vertices. Polygon entries include an integer value indicating how many vertices follow. A vertex is fed back as some number of floating-point values, as determined by TYPE. Colors are fed back as four values in RGBA mode and one value in color index mode. feedbackList ← feedbackItem feedbackList | feedbackItem feedbackItem ← point | lineSegment | polygon | bitmap | pixelRectangle | passThru point ← `GL_POINT_TOKEN' vertex lineSegment ← `GL_LINE_TOKEN' vertex vertex | `GL_LINE_RESET_TOKEN' vertex vertex polygon ← `GL_POLYGON_TOKEN' n polySpec polySpec ← polySpec vertex | vertex vertex vertex bitmap ← `GL_BITMAP_TOKEN' vertex pixelRectangle ← `GL_DRAW_PIXEL_TOKEN' vertex | `GL_COPY_PIXEL_TOKEN' vertex passThru ← `GL_PASS_THROUGH_TOKEN' value vertex ← 2d | 3d | 3dColor | 3dColorTexture | 4dColorTexture 2d ← value value 3d ← value value value 3dColor ← value value value color 3dColorTexture ← value value value color tex 4dColorTexture ← value value value value color tex color ← rgba | index rgba ← value value value value index ← value tex ← value value value value VALUE is a floating-point number, and N is a floating-point integer giving the number of vertices in the polygon. `GL_POINT_TOKEN', `GL_LINE_TOKEN', `GL_LINE_RESET_TOKEN', `GL_POLYGON_TOKEN', `GL_BITMAP_TOKEN', `GL_DRAW_PIXEL_TOKEN', `GL_COPY_PIXEL_TOKEN' and `GL_PASS_THROUGH_TOKEN' are symbolic floating-point constants. `GL_LINE_RESET_TOKEN' is returned whenever the line stipple pattern is reset. The data returned as a vertex depends on the feedback TYPE. The following table gives the correspondence between TYPE and the number of values per vertex. K is 1 in color index mode and 4 in RGBA mode. *Type* *Coordinates*, *Color*, *Texture*, *Total Number of Values* `GL_2D' X, Y, , , 2 `GL_3D' X, Y, Z, , , 3 `GL_3D_COLOR' X, Y, Z, K , , 3+K `GL_3D_COLOR_TEXTURE' X, Y, Z, K , 4 , 7+K `GL_4D_COLOR_TEXTURE' X, Y, Z, W, K , 4 , 8+K Feedback vertex coordinates are in window coordinates, except W, which is in clip coordinates. Feedback colors are lighted, if lighting is enabled. Feedback texture coordinates are generated, if texture coordinate generation is enabled. They are always transformed by the texture matrix. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if SIZE is negative. `GL_INVALID_OPERATION' is generated if `glFeedbackBuffer' is called while the render mode is `GL_FEEDBACK', or if `glRenderMode' is called with argument `GL_FEEDBACK' before `glFeedbackBuffer' is called at least once. `GL_INVALID_OPERATION' is generated if `glFeedbackBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glFinish -> void)) "Block until all GL execution is complete. `glFinish' does not return until the effects of all previously called GL commands are complete. Such effects include all changes to GL state, all changes to connection state, and all changes to the frame buffer contents. `GL_INVALID_OPERATION' is generated if `glFinish' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glFlush -> void)) "Force execution of GL commands in finite time. Different GL implementations buffer commands in several different locations, including network buffers and the graphics accelerator itself. `glFlush' empties all of these buffers, causing all issued commands to be executed as quickly as they are accepted by the actual rendering engine. Though this execution may not be completed in any particular time period, it does complete in finite time. Because any GL program might be executed over a network, or on an accelerator that buffers commands, all programs should call `glFlush' whenever they count on having all of their previously issued commands completed. For example, call `glFlush' before waiting for user input that depends on the generated image. `GL_INVALID_OPERATION' is generated if `glFlush' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glFogCoordPointer (type GLenum) (stride GLsizei) (pointer GLvoid-*) -> void)) "Define an array of fog coordinates. TYPE Specifies the data type of each fog coordinate. Symbolic constants `GL_FLOAT', or `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive fog coordinates. If STRIDE is 0, the array elements are understood to be tightly packed. The initial value is 0. POINTER Specifies a pointer to the first coordinate of the first fog coordinate in the array. The initial value is 0. `glFogCoordPointer' specifies the location and data format of an array of fog coordinates to use when rendering. TYPE specifies the data type of each fog coordinate, and STRIDE specifies the byte stride from one fog coordinate to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a fog coordinate array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as fog coordinate vertex array client-side state (`GL_FOG_COORD_ARRAY_BUFFER_BINDING'). When a fog coordinate array is specified, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the fog coordinate array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_FOG_COORD_ARRAY'. If enabled, the fog coordinate array is used when `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', `glDrawRangeElements', or `glArrayElement' is called. `GL_INVALID_ENUM' is generated if TYPE is not either `GL_FLOAT' or `GL_DOUBLE'. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glFogCoordf (coord GLfloat) -> void)) "Set the current fog coordinates. COORD Specify the fog distance. `glFogCoord' specifies the fog coordinate that is associated with each vertex and the current raster position. The value specified is interpolated and used in computing the fog color (see `glFog').") (define-gl-procedures ((glFogf (pname GLenum) (param GLfloat) -> void) (glFogi (pname GLenum) (param GLint) -> void)) "Specify fog parameters. PNAME Specifies a single-valued fog parameter. `GL_FOG_MODE', `GL_FOG_DENSITY', `GL_FOG_START', `GL_FOG_END', `GL_FOG_INDEX', and `GL_FOG_COORD_SRC' are accepted. PARAM Specifies the value that PNAME will be set to. Fog is initially disabled. While enabled, fog affects rasterized geometry, bitmaps, and pixel blocks, but not buffer clear operations. To enable and disable fog, call `glEnable' and `glDisable' with argument `GL_FOG'. `glFog' assigns the value or values in PARAMS to the fog parameter specified by PNAME. The following values are accepted for PNAME: `GL_FOG_MODE' PARAMS is a single integer or floating-point value that specifies the equation to be used to compute the fog blend factor, F . Three symbolic constants are accepted: `GL_LINEAR', `GL_EXP', and `GL_EXP2'. The equations corresponding to these symbolic constants are defined below. The initial fog mode is `GL_EXP'. `GL_FOG_DENSITY' PARAMS is a single integer or floating-point value that specifies DENSITY , the fog density used in both exponential fog equations. Only nonnegative densities are accepted. The initial fog density is 1. `GL_FOG_START' PARAMS is a single integer or floating-point value that specifies START , the near distance used in the linear fog equation. The initial near distance is 0. `GL_FOG_END' PARAMS is a single integer or floating-point value that specifies END , the far distance used in the linear fog equation. The initial far distance is 1. `GL_FOG_INDEX' PARAMS is a single integer or floating-point value that specifies I_F , the fog color index. The initial fog index is 0. `GL_FOG_COLOR' PARAMS contains four integer or floating-point values that specify C_F , the fog color. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. After conversion, all color components are clamped to the range [0,1] . The initial fog color is (0, 0, 0, 0). `GL_FOG_COORD_SRC' PARAMS contains either of the following symbolic constants: `GL_FOG_COORD' or `GL_FRAGMENT_DEPTH'. `GL_FOG_COORD' specifies that the current fog coordinate should be used as distance value in the fog color computation. `GL_FRAGMENT_DEPTH' specifies that the current fragment depth should be used as distance value in the fog computation. Fog blends a fog color with each rasterized pixel fragment's post-texturing color using a blending factor F . Factor F is computed in one of three ways, depending on the fog mode. Let C be either the distance in eye coordinate from the origin (in the case that the `GL_FOG_COORD_SRC' is `GL_FRAGMENT_DEPTH') or the current fog coordinate (in the case that `GL_FOG_COORD_SRC' is `GL_FOG_COORD'). The equation for `GL_LINEAR' fog is F=END-C,/END-START, The equation for `GL_EXP' fog is F=E^-(DENSITY·C,), The equation for `GL_EXP2' fog is F=E^-(DENSITY·C,),^2 Regardless of the fog mode, F is clamped to the range [0,1] after it is computed. Then, if the GL is in RGBA color mode, the fragment's red, green, and blue colors, represented by C_R , are replaced by C_R,^″=F×C_R+(1-F,)×C_F Fog does not affect a fragment's alpha component. In color index mode, the fragment's color index I_R is replaced by I_R,^″=I_R+(1-F,)×I_F `GL_INVALID_ENUM' is generated if PNAME is not an accepted value, or if PNAME is `GL_FOG_MODE' and PARAMS is not an accepted value. `GL_INVALID_VALUE' is generated if PNAME is `GL_FOG_DENSITY' and PARAMS is negative. `GL_INVALID_OPERATION' is generated if `glFog' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glFrontFace (mode GLenum) -> void)) "Define front- and back-facing polygons. MODE Specifies the orientation of front-facing polygons. `GL_CW' and `GL_CCW' are accepted. The initial value is `GL_CCW'. In a scene composed entirely of opaque closed surfaces, back-facing polygons are never visible. Eliminating these invisible polygons has the obvious benefit of speeding up the rendering of the image. To enable and disable elimination of back-facing polygons, call `glEnable' and `glDisable' with argument `GL_CULL_FACE'. The projection of a polygon to window coordinates is said to have clockwise winding if an imaginary object following the path from its first vertex, its second vertex, and so on, to its last vertex, and finally back to its first vertex, moves in a clockwise direction about the interior of the polygon. The polygon's winding is said to be counterclockwise if the imaginary object following the same path moves in a counterclockwise direction about the interior of the polygon. `glFrontFace' specifies whether polygons with clockwise winding in window coordinates, or counterclockwise winding in window coordinates, are taken to be front-facing. Passing `GL_CCW' to MODE selects counterclockwise polygons as front-facing; `GL_CW' selects clockwise polygons as front-facing. By default, counterclockwise polygons are taken to be front-facing. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glFrontFace' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glFrustum (left GLdouble) (right GLdouble) (bottom GLdouble) (top GLdouble) (nearVal GLdouble) (farVal GLdouble) -> void)) "Multiply the current matrix by a perspective matrix. LEFT RIGHT Specify the coordinates for the left and right vertical clipping planes. BOTTOM TOP Specify the coordinates for the bottom and top horizontal clipping planes. NEARVAL FARVAL Specify the distances to the near and far depth clipping planes. Both distances must be positive. `glFrustum' describes a perspective matrix that produces a perspective projection. The current matrix (see `glMatrixMode') is multiplied by this matrix and the result replaces the current matrix, as if `glMultMatrix' were called with the following matrix as its argument: [(2\u2062NEARVAL,/RIGHT-LEFT,, 0 A 0), (0 2\u2062NEARVAL,/TOP-BOTTOM,, B 0), (0 0 C D), (0 0 -1 0),] A=RIGHT+LEFT,/RIGHT-LEFT, B=TOP+BOTTOM,/TOP-BOTTOM, C=-FARVAL+NEARVAL,/FARVAL-NEARVAL,, D=-2\u2062FARVAL\u2062NEARVAL,/FARVAL-NEARVAL,, Typically, the matrix mode is `GL_PROJECTION', and (LEFT,BOTTOM-NEARVAL) and (RIGHT,TOP-NEARVAL) specify the points on the near clipping plane that are mapped to the lower left and upper right corners of the window, assuming that the eye is located at (0, 0, 0). -FARVAL specifies the location of the far clipping plane. Both NEARVAL and FARVAL must be positive. Use `glPushMatrix' and `glPopMatrix' to save and restore the current matrix stack. `GL_INVALID_VALUE' is generated if NEARVAL or FARVAL is not positive, or if LEFT = RIGHT, or BOTTOM = TOP, or NEAR = FAR. `GL_INVALID_OPERATION' is generated if `glFrustum' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGenBuffers (n GLsizei) (buffers GLuint-*) -> void)) "Generate buffer object names. N Specifies the number of buffer object names to be generated. BUFFERS Specifies an array in which the generated buffer object names are stored. `glGenBuffers' returns N buffer object names in BUFFERS. There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to `glGenBuffers'. Buffer object names returned by a call to `glGenBuffers' are not returned by subsequent calls, unless they are first deleted with `glDeleteBuffers'. No buffer objects are associated with the returned buffer object names until they are first bound by calling `glBindBuffer'. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glGenBuffers' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGenLists (range GLsizei) -> GLuint)) "Generate a contiguous set of empty display lists. RANGE Specifies the number of contiguous empty display lists to be generated. `glGenLists' has one argument, RANGE. It returns an integer N such that RANGE contiguous empty display lists, named N , N+1 , ... , N+RANGE-1 , are created. If RANGE is 0, if there is no group of RANGE contiguous names available, or if any error is generated, no display lists are generated, and 0 is returned. `GL_INVALID_VALUE' is generated if RANGE is negative. `GL_INVALID_OPERATION' is generated if `glGenLists' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGenQueries (n GLsizei) (ids GLuint-*) -> void)) "Generate query object names. N Specifies the number of query object names to be generated. IDS Specifies an array in which the generated query object names are stored. `glGenQueries' returns N query object names in IDS. There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to `glGenQueries'. Query object names returned by a call to `glGenQueries' are not returned by subsequent calls, unless they are first deleted with `glDeleteQueries'. No query objects are associated with the returned query object names until they are first used by calling `glBeginQuery'. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glGenQueries' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGenTextures (n GLsizei) (textures GLuint-*) -> void)) "Generate texture names. N Specifies the number of texture names to be generated. TEXTURES Specifies an array in which the generated texture names are stored. `glGenTextures' returns N texture names in TEXTURES. There is no guarantee that the names form a contiguous set of integers; however, it is guaranteed that none of the returned names was in use immediately before the call to `glGenTextures'. The generated textures have no dimensionality; they assume the dimensionality of the texture target to which they are first bound (see `glBindTexture'). Texture names returned by a call to `glGenTextures' are not returned by subsequent calls, unless they are first deleted with `glDeleteTextures'. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glGenTextures' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetActiveAttrib (program GLuint) (index GLuint) (bufSize GLsizei) (length GLsizei-*) (size GLint-*) (type GLenum-*) (name GLchar-*) -> void)) "Returns information about an active attribute variable for the specified program object. PROGRAM Specifies the program object to be queried. INDEX Specifies the index of the attribute variable to be queried. BUFSIZE Specifies the maximum number of characters OpenGL is allowed to write in the character buffer indicated by NAME. LENGTH Returns the number of characters actually written by OpenGL in the string indicated by NAME (excluding the null terminator) if a value other than `NULL' is passed. SIZE Returns the size of the attribute variable. TYPE Returns the data type of the attribute variable. NAME Returns a null terminated string containing the name of the attribute variable. `glGetActiveAttrib' returns information about an active attribute variable in the program object specified by PROGRAM. The number of active attributes can be obtained by calling `glGetProgram' with the value `GL_ACTIVE_ATTRIBUTES'. A value of 0 for INDEX selects the first active attribute variable. Permissible values for INDEX range from 0 to the number of active attribute variables minus 1. A vertex shader may use either built-in attribute variables, user-defined attribute variables, or both. Built-in attribute variables have a prefix of \"gl_\" and reference conventional OpenGL vertex attribtes (e.g., GL_VERTEX, GL_NORMAL, etc., see the OpenGL Shading Language specification for a complete list.) User-defined attribute variables have arbitrary names and obtain their values through numbered generic vertex attributes. An attribute variable (either built-in or user-defined) is considered active if it is determined during the link operation that it may be accessed during program execution. Therefore, PROGRAM should have previously been the target of a call to `glLinkProgram', but it is not necessary for it to have been linked successfully. The size of the character buffer required to store the longest attribute variable name in PROGRAM can be obtained by calling `glGetProgram' with the value `GL_ACTIVE_ATTRIBUTE_MAX_LENGTH'. This value should be used to allocate a buffer of sufficient size to store the returned attribute name. The size of this character buffer is passed in BUFSIZE, and a pointer to this character buffer is passed in NAME. `glGetActiveAttrib' returns the name of the attribute variable indicated by INDEX, storing it in the character buffer specified by NAME. The string returned will be null terminated. The actual number of characters written into this buffer is returned in LENGTH, and this count does not include the null termination character. If the length of the returned string is not required, a value of `NULL' can be passed in the LENGTH argument. The TYPE argument will return a pointer to the attribute variable's data type. The symbolic constants `GL_FLOAT', `GL_FLOAT_VEC2', `GL_FLOAT_VEC3', `GL_FLOAT_VEC4', `GL_FLOAT_MAT2', `GL_FLOAT_MAT3', `GL_FLOAT_MAT4', `GL_FLOAT_MAT2x3', `GL_FLOAT_MAT2x4', `GL_FLOAT_MAT3x2', `GL_FLOAT_MAT3x4', `GL_FLOAT_MAT4x2', or `GL_FLOAT_MAT4x3' may be returned. The SIZE argument will return the size of the attribute, in units of the type returned in TYPE. The list of active attribute variables may include both built-in attribute variables (which begin with the prefix \"gl_\") as well as user-defined attribute variable names. This function will return as much information as it can about the specified active attribute variable. If no information is available, LENGTH will be 0, and NAME will be an empty string. This situation could occur if this function is called after a link operation that failed. If an error occurs, the return values LENGTH, SIZE, TYPE, and NAME will be unmodified. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to the number of active attribute variables in PROGRAM. `GL_INVALID_OPERATION' is generated if `glGetActiveAttrib' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_VALUE' is generated if BUFSIZE is less than 0.") (define-gl-procedures ((glGetActiveUniform (program GLuint) (index GLuint) (bufSize GLsizei) (length GLsizei-*) (size GLint-*) (type GLenum-*) (name GLchar-*) -> void)) "Returns information about an active uniform variable for the specified program object. PROGRAM Specifies the program object to be queried. INDEX Specifies the index of the uniform variable to be queried. BUFSIZE Specifies the maximum number of characters OpenGL is allowed to write in the character buffer indicated by NAME. LENGTH Returns the number of characters actually written by OpenGL in the string indicated by NAME (excluding the null terminator) if a value other than `NULL' is passed. SIZE Returns the size of the uniform variable. TYPE Returns the data type of the uniform variable. NAME Returns a null terminated string containing the name of the uniform variable. `glGetActiveUniform' returns information about an active uniform variable in the program object specified by PROGRAM. The number of active uniform variables can be obtained by calling `glGetProgram' with the value `GL_ACTIVE_UNIFORMS'. A value of 0 for INDEX selects the first active uniform variable. Permissible values for INDEX range from 0 to the number of active uniform variables minus 1. Shaders may use either built-in uniform variables, user-defined uniform variables, or both. Built-in uniform variables have a prefix of \"gl_\" and reference existing OpenGL state or values derived from such state (e.g., GL_FOG, GL_MODELVIEWMATRIX, etc., see the OpenGL Shading Language specification for a complete list.) User-defined uniform variables have arbitrary names and obtain their values from the application through calls to `glUniform'. A uniform variable (either built-in or user-defined) is considered active if it is determined during the link operation that it may be accessed during program execution. Therefore, PROGRAM should have previously been the target of a call to `glLinkProgram', but it is not necessary for it to have been linked successfully. The size of the character buffer required to store the longest uniform variable name in PROGRAM can be obtained by calling `glGetProgram' with the value `GL_ACTIVE_UNIFORM_MAX_LENGTH'. This value should be used to allocate a buffer of sufficient size to store the returned uniform variable name. The size of this character buffer is passed in BUFSIZE, and a pointer to this character buffer is passed in NAME. `glGetActiveUniform' returns the name of the uniform variable indicated by INDEX, storing it in the character buffer specified by NAME. The string returned will be null terminated. The actual number of characters written into this buffer is returned in LENGTH, and this count does not include the null termination character. If the length of the returned string is not required, a value of `NULL' can be passed in the LENGTH argument. The TYPE argument will return a pointer to the uniform variable's data type. The symbolic constants `GL_FLOAT', `GL_FLOAT_VEC2', `GL_FLOAT_VEC3', `GL_FLOAT_VEC4', `GL_INT', `GL_INT_VEC2', `GL_INT_VEC3', `GL_INT_VEC4', `GL_BOOL', `GL_BOOL_VEC2', `GL_BOOL_VEC3', `GL_BOOL_VEC4', `GL_FLOAT_MAT2', `GL_FLOAT_MAT3', `GL_FLOAT_MAT4', `GL_FLOAT_MAT2x3', `GL_FLOAT_MAT2x4', `GL_FLOAT_MAT3x2', `GL_FLOAT_MAT3x4', `GL_FLOAT_MAT4x2', `GL_FLOAT_MAT4x3', `GL_SAMPLER_1D', `GL_SAMPLER_2D', `GL_SAMPLER_3D', `GL_SAMPLER_CUBE', `GL_SAMPLER_1D_SHADOW', or `GL_SAMPLER_2D_SHADOW' may be returned. If one or more elements of an array are active, the name of the array is returned in NAME, the type is returned in TYPE, and the SIZE parameter returns the highest array element index used, plus one, as determined by the compiler and/or linker. Only one active uniform variable will be reported for a uniform array. Uniform variables that are declared as structures or arrays of structures will not be returned directly by this function. Instead, each of these uniform variables will be reduced to its fundamental components containing the \".\" and \"[]\" operators such that each of the names is valid as an argument to `glGetUniformLocation'. Each of these reduced uniform variables is counted as one active uniform variable and is assigned an index. A valid name cannot be a structure, an array of structures, or a subcomponent of a vector or matrix. The size of the uniform variable will be returned in SIZE. Uniform variables other than arrays will have a size of 1. Structures and arrays of structures will be reduced as described earlier, such that each of the names returned will be a data type in the earlier list. If this reduction results in an array, the size returned will be as described for uniform arrays; otherwise, the size returned will be 1. The list of active uniform variables may include both built-in uniform variables (which begin with the prefix \"gl_\") as well as user-defined uniform variable names. This function will return as much information as it can about the specified active uniform variable. If no information is available, LENGTH will be 0, and NAME will be an empty string. This situation could occur if this function is called after a link operation that failed. If an error occurs, the return values LENGTH, SIZE, TYPE, and NAME will be unmodified. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to the number of active uniform variables in PROGRAM. `GL_INVALID_OPERATION' is generated if `glGetActiveUniform' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_VALUE' is generated if BUFSIZE is less than 0.") (define-gl-procedures ((glGetAttachedShaders (program GLuint) (maxCount GLsizei) (count GLsizei-*) (shaders GLuint-*) -> void)) "Returns the handles of the shader objects attached to a program object. PROGRAM Specifies the program object to be queried. MAXCOUNT Specifies the size of the array for storing the returned object names. COUNT Returns the number of names actually returned in OBJECTS. SHADERS Specifies an array that is used to return the names of attached shader objects. `glGetAttachedShaders' returns the names of the shader objects attached to PROGRAM. The names of shader objects that are attached to PROGRAM will be returned in SHADERS. The actual number of shader names written into SHADERS is returned in COUNT. If no shader objects are attached to PROGRAM, COUNT is set to 0. The maximum number of shader names that may be returned in SHADERS is specified by MAXCOUNT. If the number of names actually returned is not required (for instance, if it has just been obtained by calling `glGetProgram'), a value of `NULL' may be passed for count. If no shader objects are attached to PROGRAM, a value of 0 will be returned in COUNT. The actual number of attached shaders can be obtained by calling `glGetProgram' with the value `GL_ATTACHED_SHADERS'. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_VALUE' is generated if MAXCOUNT is less than 0. `GL_INVALID_OPERATION' is generated if `glGetAttachedShaders' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetAttribLocation (program GLuint) (name const-GLchar-*) -> GLint)) "Returns the location of an attribute variable. PROGRAM Specifies the program object to be queried. NAME Points to a null terminated string containing the name of the attribute variable whose location is to be queried. `glGetAttribLocation' queries the previously linked program object specified by PROGRAM for the attribute variable specified by NAME and returns the index of the generic vertex attribute that is bound to that attribute variable. If NAME is a matrix attribute variable, the index of the first column of the matrix is returned. If the named attribute variable is not an active attribute in the specified program object or if NAME starts with the reserved prefix \"gl_\", a value of -1 is returned. The association between an attribute variable name and a generic attribute index can be specified at any time by calling `glBindAttribLocation'. Attribute bindings do not go into effect until `glLinkProgram' is called. After a program object has been linked successfully, the index values for attribute variables remain fixed until the next link command occurs. The attribute values can only be queried after a link if the link was successful. `glGetAttribLocation' returns the binding that actually went into effect the last time `glLinkProgram' was called for the specified program object. Attribute bindings that have been specified since the last link operation are not returned by `glGetAttribLocation'. `GL_INVALID_OPERATION' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if PROGRAM has not been successfully linked. `GL_INVALID_OPERATION' is generated if `glGetAttribLocation' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetBufferParameteriv (target GLenum) (value GLenum) (data GLint-*) -> void)) "Return parameters of a buffer object. TARGET Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. VALUE Specifies the symbolic name of a buffer object parameter. Accepted values are `GL_BUFFER_ACCESS', `GL_BUFFER_MAPPED', `GL_BUFFER_SIZE', or `GL_BUFFER_USAGE'. DATA Returns the requested parameter. `glGetBufferParameteriv' returns in DATA a selected parameter of the buffer object specified by TARGET. VALUE names a specific buffer object parameter, as follows: `GL_BUFFER_ACCESS' PARAMS returns the access policy set while mapping the buffer object. The initial value is `GL_READ_WRITE'. `GL_BUFFER_MAPPED' PARAMS returns a flag indicating whether the buffer object is currently mapped. The initial value is `GL_FALSE'. `GL_BUFFER_SIZE' PARAMS returns the size of the buffer object, measured in bytes. The initial value is 0. `GL_BUFFER_USAGE' PARAMS returns the buffer object's usage pattern. The initial value is `GL_STATIC_DRAW'. `GL_INVALID_ENUM' is generated if TARGET or VALUE is not an accepted value. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_INVALID_OPERATION' is generated if `glGetBufferParameteriv' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetBufferPointerv (target GLenum) (pname GLenum) (params GLvoid-**) -> void)) "Return the pointer to a mapped buffer object's data store. TARGET Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. PNAME Specifies the pointer to be returned. The symbolic constant must be `GL_BUFFER_MAP_POINTER'. PARAMS Returns the pointer value specified by PNAME. `glGetBufferPointerv' returns pointer information. PNAME is a symbolic constant indicating the pointer to be returned, which must be `GL_BUFFER_MAP_POINTER', the pointer to which the buffer object's data store is mapped. If the data store is not currently mapped, `NULL' is returned. PARAMS is a pointer to a location in which to place the returned pointer value. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_INVALID_OPERATION' is generated if `glGetBufferPointerv' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetBufferSubData (target GLenum) (offset GLintptr) (size GLsizeiptr) (data GLvoid-*) -> void)) "Returns a subset of a buffer object's data store. TARGET Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. OFFSET Specifies the offset into the buffer object's data store from which data will be returned, measured in bytes. SIZE Specifies the size in bytes of the data store region being returned. DATA Specifies a pointer to the location where buffer object data is returned. `glGetBufferSubData' returns some or all of the data from the buffer object currently bound to TARGET. Data starting at byte offset OFFSET and extending for SIZE bytes is copied from the data store to the memory pointed to by DATA. An error is thrown if the buffer object is currently mapped, or if OFFSET and SIZE together define a range beyond the bounds of the buffer object's data store. `GL_INVALID_ENUM' is generated if TARGET is not `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. `GL_INVALID_VALUE' is generated if OFFSET or SIZE is negative, or if together they define a region of memory that extends beyond the buffer object's allocated data store. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_INVALID_OPERATION' is generated if the buffer object being queried is mapped. `GL_INVALID_OPERATION' is generated if `glGetBufferSubData' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetClipPlane (plane GLenum) (equation GLdouble-*) -> void)) "Return the coefficients of the specified clipping plane. PLANE Specifies a clipping plane. The number of clipping planes depends on the implementation, but at least six clipping planes are supported. They are identified by symbolic names of the form `GL_CLIP_PLANE' I where i ranges from 0 to the value of `GL_MAX_CLIP_PLANES' - 1. EQUATION Returns four double-precision values that are the coefficients of the plane equation of PLANE in eye coordinates. The initial value is (0, 0, 0, 0). `glGetClipPlane' returns in EQUATION the four coefficients of the plane equation for PLANE. `GL_INVALID_ENUM' is generated if PLANE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetClipPlane' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetColorTableParameterfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetColorTableParameteriv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Get color lookup table parameters. TARGET The target color table. Must be `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', `GL_POST_COLOR_MATRIX_COLOR_TABLE', `GL_PROXY_COLOR_TABLE', `GL_PROXY_POST_CONVOLUTION_COLOR_TABLE', or `GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE'. PNAME The symbolic name of a color lookup table parameter. Must be one of `GL_COLOR_TABLE_BIAS', `GL_COLOR_TABLE_SCALE', `GL_COLOR_TABLE_FORMAT', `GL_COLOR_TABLE_WIDTH', `GL_COLOR_TABLE_RED_SIZE', `GL_COLOR_TABLE_GREEN_SIZE', `GL_COLOR_TABLE_BLUE_SIZE', `GL_COLOR_TABLE_ALPHA_SIZE', `GL_COLOR_TABLE_LUMINANCE_SIZE', or `GL_COLOR_TABLE_INTENSITY_SIZE'. PARAMS A pointer to an array where the values of the parameter will be stored. Returns parameters specific to color table TARGET. When PNAME is set to `GL_COLOR_TABLE_SCALE' or `GL_COLOR_TABLE_BIAS', `glGetColorTableParameter' returns the color table scale or bias parameters for the table specified by TARGET. For these queries, TARGET must be set to `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE' and PARAMS points to an array of four elements, which receive the scale or bias factors for red, green, blue, and alpha, in that order. `glGetColorTableParameter' can also be used to retrieve the format and size parameters for a color table. For these queries, set TARGET to either the color table target or the proxy color table target. The format and size parameters are set by `glColorTable'. The following table lists the format and size parameters that may be queried. For each symbolic constant listed below for PNAME, PARAMS must point to an array of the given length and receive the values indicated. *Parameter* *N*, *Meaning* `GL_COLOR_TABLE_FORMAT' 1 , Internal format (e.g., `GL_RGBA') `GL_COLOR_TABLE_WIDTH' 1 , Number of elements in table `GL_COLOR_TABLE_RED_SIZE' 1 , Size of red component, in bits `GL_COLOR_TABLE_GREEN_SIZE' 1 , Size of green component `GL_COLOR_TABLE_BLUE_SIZE' 1 , Size of blue component `GL_COLOR_TABLE_ALPHA_SIZE' 1 , Size of alpha component `GL_COLOR_TABLE_LUMINANCE_SIZE' 1 , Size of luminance component `GL_COLOR_TABLE_INTENSITY_SIZE' 1 , Size of intensity component `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an acceptable value. `GL_INVALID_OPERATION' is generated if `glGetColorTableParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetColorTable (target GLenum) (format GLenum) (type GLenum) (table GLvoid-*) -> void)) "Retrieve contents of a color lookup table. TARGET Must be `GL_COLOR_TABLE', `GL_POST_CONVOLUTION_COLOR_TABLE', or `GL_POST_COLOR_MATRIX_COLOR_TABLE'. FORMAT The format of the pixel data in TABLE. The possible values are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', and `GL_BGRA'. TYPE The type of the pixel data in TABLE. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. TABLE Pointer to a one-dimensional array of pixel data containing the contents of the color table. `glGetColorTable' returns in TABLE the contents of the color table specified by TARGET. No pixel transfer operations are performed, but pixel storage modes that are applicable to `glReadPixels' are performed. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a histogram table is requested, TABLE is treated as a byte offset into the buffer object's data store. Color components that are requested in the specified FORMAT, but which are not included in the internal format of the color lookup table, are returned as zero. The assignments of internal color components to the components requested by FORMAT are *Internal Component* *Resulting Component* Red Red Green Green Blue Blue Alpha Alpha Luminance Red Intensity Red `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and TABLE is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetColorTable' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetCompressedTexImage (target GLenum) (lod GLint) (img GLvoid-*) -> void)) "Return a compressed texture image. TARGET Specifies which texture is to be obtained. `GL_TEXTURE_1D', `GL_TEXTURE_2D', and `GL_TEXTURE_3D'`GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', and `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z' are accepted. LOD Specifies the level-of-detail number of the desired image. Level 0 is the base image level. Level N is the N th mipmap reduction image. IMG Returns the compressed texture image. `glGetCompressedTexImage' returns the compressed texture image associated with TARGET and LOD into IMG. IMG should be an array of `GL_TEXTURE_COMPRESSED_IMAGE_SIZE' bytes. TARGET specifies whether the desired texture image was one specified by `glTexImage1D' (`GL_TEXTURE_1D'), `glTexImage2D' (`GL_TEXTURE_2D' or any of `GL_TEXTURE_CUBE_MAP_*'), or `glTexImage3D' (`GL_TEXTURE_3D'). LOD specifies the level-of-detail number of the desired image. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a texture image is requested, IMG is treated as a byte offset into the buffer object's data store. To minimize errors, first verify that the texture is compressed by calling `glGetTexLevelParameter' with argument `GL_TEXTURE_COMPRESSED'. If the texture is compressed, then determine the amount of memory required to store the compressed texture by calling `glGetTexLevelParameter' with argument `GL_TEXTURE_COMPRESSED_IMAGE_SIZE'. Finally, retrieve the internal format of the texture by calling `glGetTexLevelParameter' with argument `GL_TEXTURE_INTERNAL_FORMAT'. To store the texture for later use, associate the internal format and size with the retrieved texture image. These data can be used by the respective texture or subtexture loading routine used for loading TARGET textures. `GL_INVALID_VALUE' is generated if LOD is less than zero or greater than the maximum number of LODs permitted by the implementation. `GL_INVALID_OPERATION' is generated if `glGetCompressedTexImage' is used to retrieve a texture that is in an uncompressed internal format. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glGetCompressedTexImage' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetConvolutionFilter (target GLenum) (format GLenum) (type GLenum) (image GLvoid-*) -> void)) "Get current 1D or 2D convolution filter kernel. TARGET The filter to be retrieved. Must be one of `GL_CONVOLUTION_1D' or `GL_CONVOLUTION_2D'. FORMAT Format of the output image. Must be one of `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', or `GL_LUMINANCE_ALPHA'. TYPE Data type of components in the output image. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. IMAGE Pointer to storage for the output image. `glGetConvolutionFilter' returns the current 1D or 2D convolution filter kernel as an image. The one- or two-dimensional image is placed in IMAGE according to the specifications in FORMAT and TYPE. No pixel transfer operations are performed on this image, but the relevant pixel storage modes are applied. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a convolution filter is requested, IMAGE is treated as a byte offset into the buffer object's data store. Color components that are present in FORMAT but not included in the internal format of the filter are returned as zero. The assignments of internal color components to the components of FORMAT are as follows. *Internal Component* *Resulting Component* Red Red Green Green Blue Blue Alpha Alpha Luminance Red Intensity Red `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and IMAGE is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetConvolutionFilter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetConvolutionParameterfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetConvolutionParameteriv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Get convolution parameters. TARGET The filter whose parameters are to be retrieved. Must be one of `GL_CONVOLUTION_1D', `GL_CONVOLUTION_2D', or `GL_SEPARABLE_2D'. PNAME The parameter to be retrieved. Must be one of `GL_CONVOLUTION_BORDER_MODE', `GL_CONVOLUTION_BORDER_COLOR', `GL_CONVOLUTION_FILTER_SCALE', `GL_CONVOLUTION_FILTER_BIAS', `GL_CONVOLUTION_FORMAT', `GL_CONVOLUTION_WIDTH', `GL_CONVOLUTION_HEIGHT', `GL_MAX_CONVOLUTION_WIDTH', or `GL_MAX_CONVOLUTION_HEIGHT'. PARAMS Pointer to storage for the parameters to be retrieved. `glGetConvolutionParameter' retrieves convolution parameters. TARGET determines which convolution filter is queried. PNAME determines which parameter is returned: `GL_CONVOLUTION_BORDER_MODE' The convolution border mode. See `glConvolutionParameter' for a list of border modes. `GL_CONVOLUTION_BORDER_COLOR' The current convolution border color. PARAMS must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha border colors. `GL_CONVOLUTION_FILTER_SCALE' The current filter scale factors. PARAMS must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter scale factors in that order. `GL_CONVOLUTION_FILTER_BIAS' The current filter bias factors. PARAMS must be a pointer to an array of four elements, which will receive the red, green, blue, and alpha filter bias terms in that order. `GL_CONVOLUTION_FORMAT' The current internal format. See `glConvolutionFilter1D', `glConvolutionFilter2D', and `glSeparableFilter2D' for lists of allowable formats. `GL_CONVOLUTION_WIDTH' The current filter image width. `GL_CONVOLUTION_HEIGHT' The current filter image height. `GL_MAX_CONVOLUTION_WIDTH' The maximum acceptable filter image width. `GL_MAX_CONVOLUTION_HEIGHT' The maximum acceptable filter image height. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if PNAME is not one of the allowable values. `GL_INVALID_ENUM' is generated if TARGET is `GL_CONVOLUTION_1D' and PNAME is `GL_CONVOLUTION_HEIGHT' or `GL_MAX_CONVOLUTION_HEIGHT'. `GL_INVALID_OPERATION' is generated if `glGetConvolutionParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetError -> GLenum)) "Return error information. `glGetError' returns the value of the error flag. Each detectable error is assigned a numeric code and symbolic name. When an error occurs, the error flag is set to the appropriate error code value. No other errors are recorded until `glGetError' is called, the error code is returned, and the flag is reset to `GL_NO_ERROR'. If a call to `glGetError' returns `GL_NO_ERROR', there has been no detectable error since the last call to `glGetError', or since the GL was initialized. To allow for distributed implementations, there may be several error flags. If any single error flag has recorded an error, the value of that flag is returned and that flag is reset to `GL_NO_ERROR' when `glGetError' is called. If more than one flag has recorded an error, `glGetError' returns and clears an arbitrary error flag value. Thus, `glGetError' should always be called in a loop, until it returns `GL_NO_ERROR', if all error flags are to be reset. Initially, all error flags are set to `GL_NO_ERROR'. The following errors are currently defined: `GL_NO_ERROR' No error has been recorded. The value of this symbolic constant is guaranteed to be 0. `GL_INVALID_ENUM' An unacceptable value is specified for an enumerated argument. The offending command is ignored and has no other side effect than to set the error flag. `GL_INVALID_VALUE' A numeric argument is out of range. The offending command is ignored and has no other side effect than to set the error flag. `GL_INVALID_OPERATION' The specified operation is not allowed in the current state. The offending command is ignored and has no other side effect than to set the error flag. `GL_STACK_OVERFLOW' This command would cause a stack overflow. The offending command is ignored and has no other side effect than to set the error flag. `GL_STACK_UNDERFLOW' This command would cause a stack underflow. The offending command is ignored and has no other side effect than to set the error flag. `GL_OUT_OF_MEMORY' There is not enough memory left to execute the command. The state of the GL is undefined, except for the state of the error flags, after this error is recorded. `GL_TABLE_TOO_LARGE' The specified table exceeds the implementation's maximum supported table size. The offending command is ignored and has no other side effect than to set the error flag. When an error flag is set, results of a GL operation are undefined only if `GL_OUT_OF_MEMORY' has occurred. In all other cases, the command generating the error is ignored and has no effect on the GL state or frame buffer contents. If the generating command returns a value, it returns 0. If `glGetError' itself generates an error, it returns 0. `GL_INVALID_OPERATION' is generated if `glGetError' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. In this case, `glGetError' returns 0.") (define-gl-procedures ((glGetHistogramParameterfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetHistogramParameteriv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Get histogram parameters. TARGET Must be one of `GL_HISTOGRAM' or `GL_PROXY_HISTOGRAM'. PNAME The name of the parameter to be retrieved. Must be one of `GL_HISTOGRAM_WIDTH', `GL_HISTOGRAM_FORMAT', `GL_HISTOGRAM_RED_SIZE', `GL_HISTOGRAM_GREEN_SIZE', `GL_HISTOGRAM_BLUE_SIZE', `GL_HISTOGRAM_ALPHA_SIZE', `GL_HISTOGRAM_LUMINANCE_SIZE', or `GL_HISTOGRAM_SINK'. PARAMS Pointer to storage for the returned values. `glGetHistogramParameter' is used to query parameter values for the current histogram or for a proxy. The histogram state information may be queried by calling `glGetHistogramParameter' with a TARGET of `GL_HISTOGRAM' (to obtain information for the current histogram table) or `GL_PROXY_HISTOGRAM' (to obtain information from the most recent proxy request) and one of the following values for the PNAME argument: *Parameter* *Description* `GL_HISTOGRAM_WIDTH' Histogram table width `GL_HISTOGRAM_FORMAT' Internal format `GL_HISTOGRAM_RED_SIZE' Red component counter size, in bits `GL_HISTOGRAM_GREEN_SIZE' Green component counter size, in bits `GL_HISTOGRAM_BLUE_SIZE' Blue component counter size, in bits `GL_HISTOGRAM_ALPHA_SIZE' Alpha component counter size, in bits `GL_HISTOGRAM_LUMINANCE_SIZE' Luminance component counter size, in bits `GL_HISTOGRAM_SINK' Value of the SINK parameter `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if PNAME is not one of the allowable values. `GL_INVALID_OPERATION' is generated if `glGetHistogramParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetHistogram (target GLenum) (reset GLboolean) (format GLenum) (type GLenum) (values GLvoid-*) -> void)) "Get histogram table. TARGET Must be `GL_HISTOGRAM'. RESET If `GL_TRUE', each component counter that is actually returned is reset to zero. (Other counters are unaffected.) If `GL_FALSE', none of the counters in the histogram table is modified. FORMAT The format of values to be returned in VALUES. Must be one of `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', or `GL_LUMINANCE_ALPHA'. TYPE The type of values to be returned in VALUES. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. VALUES A pointer to storage for the returned histogram table. `glGetHistogram' returns the current histogram table as a one-dimensional image with the same width as the histogram. No pixel transfer operations are performed on this image, but pixel storage modes that are applicable to 1D images are honored. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a histogram table is requested, VALUES is treated as a byte offset into the buffer object's data store. Color components that are requested in the specified FORMAT, but which are not included in the internal format of the histogram, are returned as zero. The assignments of internal color components to the components requested by FORMAT are: *Internal Component* *Resulting Component* Red Red Green Green Blue Blue Alpha Alpha Luminance Red `GL_INVALID_ENUM' is generated if TARGET is not `GL_HISTOGRAM'. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and VALUES is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetHistogram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetLightfv (light GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetLightiv (light GLenum) (pname GLenum) (params GLint-*) -> void)) "Return light source parameter values. LIGHT Specifies a light source. The number of possible lights depends on the implementation, but at least eight lights are supported. They are identified by symbolic names of the form `GL_LIGHT' I where I ranges from 0 to the value of `GL_MAX_LIGHTS' - 1. PNAME Specifies a light source parameter for LIGHT. Accepted symbolic names are `GL_AMBIENT', `GL_DIFFUSE', `GL_SPECULAR', `GL_POSITION', `GL_SPOT_DIRECTION', `GL_SPOT_EXPONENT', `GL_SPOT_CUTOFF', `GL_CONSTANT_ATTENUATION', `GL_LINEAR_ATTENUATION', and `GL_QUADRATIC_ATTENUATION'. PARAMS Returns the requested data. `glGetLight' returns in PARAMS the value or values of a light source parameter. LIGHT names the light and is a symbolic name of the form `GL_LIGHT'I where i ranges from 0 to the value of `GL_MAX_LIGHTS' - 1. `GL_MAX_LIGHTS' is an implementation dependent constant that is greater than or equal to eight. PNAME specifies one of ten light source parameters, again by symbolic name. The following parameters are defined: `GL_AMBIENT' PARAMS returns four integer or floating-point values representing the ambient intensity of the light source. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1). `GL_DIFFUSE' PARAMS returns four integer or floating-point values representing the diffuse intensity of the light source. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value for `GL_LIGHT0' is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 0). `GL_SPECULAR' PARAMS returns four integer or floating-point values representing the specular intensity of the light source. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value for `GL_LIGHT0' is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 0). `GL_POSITION' PARAMS returns four integer or floating-point values representing the position of the light source. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer value. The returned values are those maintained in eye coordinates. They will not be equal to the values specified using `glLight', unless the modelview matrix was identity at the time `glLight' was called. The initial value is (0, 0, 1, 0). `GL_SPOT_DIRECTION' PARAMS returns three integer or floating-point values representing the direction of the light source. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer value. The returned values are those maintained in eye coordinates. They will not be equal to the values specified using `glLight', unless the modelview matrix was identity at the time `glLight' was called. Although spot direction is normalized before being used in the lighting equation, the returned values are the transformed versions of the specified values prior to normalization. The initial value is (0,0-1) . `GL_SPOT_EXPONENT' PARAMS returns a single integer or floating-point value representing the spot exponent of the light. An integer value, when requested, is computed by rounding the internal floating-point representation to the nearest integer. The initial value is 0. `GL_SPOT_CUTOFF' PARAMS returns a single integer or floating-point value representing the spot cutoff angle of the light. An integer value, when requested, is computed by rounding the internal floating-point representation to the nearest integer. The initial value is 180. `GL_CONSTANT_ATTENUATION' PARAMS returns a single integer or floating-point value representing the constant (not distance-related) attenuation of the light. An integer value, when requested, is computed by rounding the internal floating-point representation to the nearest integer. The initial value is 1. `GL_LINEAR_ATTENUATION' PARAMS returns a single integer or floating-point value representing the linear attenuation of the light. An integer value, when requested, is computed by rounding the internal floating-point representation to the nearest integer. The initial value is 0. `GL_QUADRATIC_ATTENUATION' PARAMS returns a single integer or floating-point value representing the quadratic attenuation of the light. An integer value, when requested, is computed by rounding the internal floating-point representation to the nearest integer. The initial value is 0. `GL_INVALID_ENUM' is generated if LIGHT or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetLight' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetMapfv (target GLenum) (query GLenum) (v GLfloat-*) -> void) (glGetMapiv (target GLenum) (query GLenum) (v GLint-*) -> void)) "Return evaluator parameters. TARGET Specifies the symbolic name of a map. Accepted values are `GL_MAP1_COLOR_4', `GL_MAP1_INDEX', `GL_MAP1_NORMAL', `GL_MAP1_TEXTURE_COORD_1', `GL_MAP1_TEXTURE_COORD_2', `GL_MAP1_TEXTURE_COORD_3', `GL_MAP1_TEXTURE_COORD_4', `GL_MAP1_VERTEX_3', `GL_MAP1_VERTEX_4', `GL_MAP2_COLOR_4', `GL_MAP2_INDEX', `GL_MAP2_NORMAL', `GL_MAP2_TEXTURE_COORD_1', `GL_MAP2_TEXTURE_COORD_2', `GL_MAP2_TEXTURE_COORD_3', `GL_MAP2_TEXTURE_COORD_4', `GL_MAP2_VERTEX_3', and `GL_MAP2_VERTEX_4'. QUERY Specifies which parameter to return. Symbolic names `GL_COEFF', `GL_ORDER', and `GL_DOMAIN' are accepted. V Returns the requested data. `glMap1' and `glMap2' define evaluators. `glGetMap' returns evaluator parameters. TARGET chooses a map, QUERY selects a specific parameter, and V points to storage where the values will be returned. The acceptable values for the TARGET parameter are described in the `glMap1' and `glMap2' reference pages. QUERY can assume the following values: `GL_COEFF' V returns the control points for the evaluator function. One-dimensional evaluators return ORDER control points, and two-dimensional evaluators return UORDER×VORDER control points. Each control point consists of one, two, three, or four integer, single-precision floating-point, or double-precision floating-point values, depending on the type of the evaluator. The GL returns two-dimensional control points in row-major order, incrementing the UORDER index quickly and the VORDER index after each row. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values. `GL_ORDER' V returns the order of the evaluator function. One-dimensional evaluators return a single value, ORDER . The initial value is 1. Two-dimensional evaluators return two values, UORDER and VORDER . The initial value is 1,1. `GL_DOMAIN' V returns the linear U and V mapping parameters. One-dimensional evaluators return two values, U1 and U2 , as specified by `glMap1'. Two-dimensional evaluators return four values ( U1 , U2 , V1 , and V2 ) as specified by `glMap2'. Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values. `GL_INVALID_ENUM' is generated if either TARGET or QUERY is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetMap' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetMaterialfv (face GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetMaterialiv (face GLenum) (pname GLenum) (params GLint-*) -> void)) "Return material parameters. FACE Specifies which of the two materials is being queried. `GL_FRONT' or `GL_BACK' are accepted, representing the front and back materials, respectively. PNAME Specifies the material parameter to return. `GL_AMBIENT', `GL_DIFFUSE', `GL_SPECULAR', `GL_EMISSION', `GL_SHININESS', and `GL_COLOR_INDEXES' are accepted. PARAMS Returns the requested data. `glGetMaterial' returns in PARAMS the value or values of parameter PNAME of material FACE. Six parameters are defined: `GL_AMBIENT' PARAMS returns four integer or floating-point values representing the ambient reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value is (0.2, 0.2, 0.2, 1.0) `GL_DIFFUSE' PARAMS returns four integer or floating-point values representing the diffuse reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value is (0.8, 0.8, 0.8, 1.0). `GL_SPECULAR' PARAMS returns four integer or floating-point values representing the specular reflectance of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1). `GL_EMISSION' PARAMS returns four integer or floating-point values representing the emitted light intensity of the material. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer value, and -1.0 maps to the most negative representable integer value. If the internal value is outside the range [-1,1] , the corresponding integer return value is undefined. The initial value is (0, 0, 0, 1). `GL_SHININESS' PARAMS returns one integer or floating-point value representing the specular exponent of the material. Integer values, when requested, are computed by rounding the internal floating-point value to the nearest integer value. The initial value is 0. `GL_COLOR_INDEXES' PARAMS returns three integer or floating-point values representing the ambient, diffuse, and specular indices of the material. These indices are used only for color index lighting. (All the other parameters are used only for RGBA lighting.) Integer values, when requested, are computed by rounding the internal floating-point values to the nearest integer values. `GL_INVALID_ENUM' is generated if FACE or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetMaterial' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetMinmaxParameterfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetMinmaxParameteriv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Get minmax parameters. TARGET Must be `GL_MINMAX'. PNAME The parameter to be retrieved. Must be one of `GL_MINMAX_FORMAT' or `GL_MINMAX_SINK'. PARAMS A pointer to storage for the retrieved parameters. `glGetMinmaxParameter' retrieves parameters for the current minmax table by setting PNAME to one of the following values: *Parameter* *Description* `GL_MINMAX_FORMAT' Internal format of minmax table `GL_MINMAX_SINK' Value of the SINK parameter `GL_INVALID_ENUM' is generated if TARGET is not `GL_MINMAX'. `GL_INVALID_ENUM' is generated if PNAME is not one of the allowable values. `GL_INVALID_OPERATION' is generated if `glGetMinmaxParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetMinmax (target GLenum) (reset GLboolean) (format GLenum) (types GLenum) (values GLvoid-*) -> void)) "Get minimum and maximum pixel values. TARGET Must be `GL_MINMAX'. RESET If `GL_TRUE', all entries in the minmax table that are actually returned are reset to their initial values. (Other entries are unaltered.) If `GL_FALSE', the minmax table is unaltered. FORMAT The format of the data to be returned in VALUES. Must be one of `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', or `GL_LUMINANCE_ALPHA'. TYPES The type of the data to be returned in VALUES. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. VALUES A pointer to storage for the returned values. `glGetMinmax' returns the accumulated minimum and maximum pixel values (computed on a per-component basis) in a one-dimensional image of width 2. The first set of return values are the minima, and the second set of return values are the maxima. The format of the return values is determined by FORMAT, and their type is determined by TYPES. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while minimum and maximum pixel values are requested, VALUES is treated as a byte offset into the buffer object's data store. No pixel transfer operations are performed on the return values, but pixel storage modes that are applicable to one-dimensional images are performed. Color components that are requested in the specified FORMAT, but that are not included in the internal format of the minmax table, are returned as zero. The assignment of internal color components to the components requested by FORMAT are as follows: *Internal Component* *Resulting Component* Red Red Green Green Blue Blue Alpha Alpha Luminance Red If RESET is `GL_TRUE', the minmax table entries corresponding to the return values are reset to their initial values. Minimum and maximum values that are not returned are not modified, even if RESET is `GL_TRUE'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_MINMAX'. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPES is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TYPES is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPES is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and VALUES is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetMinmax' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetPixelMapfv (map GLenum) (data GLfloat-*) -> void) (glGetPixelMapuiv (map GLenum) (data GLuint-*) -> void)) "Return the specified pixel map. MAP Specifies the name of the pixel map to return. Accepted values are `GL_PIXEL_MAP_I_TO_I', `GL_PIXEL_MAP_S_TO_S', `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', `GL_PIXEL_MAP_I_TO_A', `GL_PIXEL_MAP_R_TO_R', `GL_PIXEL_MAP_G_TO_G', `GL_PIXEL_MAP_B_TO_B', and `GL_PIXEL_MAP_A_TO_A'. DATA Returns the pixel map contents. See the `glPixelMap' reference page for a description of the acceptable values for the MAP parameter. `glGetPixelMap' returns in DATA the contents of the pixel map specified in MAP. Pixel maps are used during the execution of `glReadPixels', `glDrawPixels', `glCopyPixels', `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', `glTexSubImage3D', `glCopyTexImage1D', `glCopyTexImage2D', `glCopyTexSubImage1D', `glCopyTexSubImage2D', and `glCopyTexSubImage3D'. to map color indices, stencil indices, color components, and depth components to other values. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a pixel map is requested, DATA is treated as a byte offset into the buffer object's data store. Unsigned integer values, if requested, are linearly mapped from the internal fixed or floating-point representation such that 1.0 maps to the largest representable integer value, and 0.0 maps to 0. Return unsigned integer values are undefined if the map value was not in the range [0,1]. To determine the required size of MAP, call `glGet' with the appropriate symbolic constant. `GL_INVALID_ENUM' is generated if MAP is not an accepted value. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated by `glGetPixelMapfv' if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a GLfloat datum. `GL_INVALID_OPERATION' is generated by `glGetPixelMapuiv' if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a GLuint datum. `GL_INVALID_OPERATION' is generated by `glGetPixelMapusv' if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a GLushort datum. `GL_INVALID_OPERATION' is generated if `glGetPixelMap' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetPointerv (pname GLenum) (params GLvoid-**) -> void)) "Return the address of the specified pointer. PNAME Specifies the array or buffer pointer to be returned. Symbolic constants `GL_COLOR_ARRAY_POINTER', `GL_EDGE_FLAG_ARRAY_POINTER', `GL_FOG_COORD_ARRAY_POINTER', `GL_FEEDBACK_BUFFER_POINTER', `GL_INDEX_ARRAY_POINTER', `GL_NORMAL_ARRAY_POINTER', `GL_SECONDARY_COLOR_ARRAY_POINTER', `GL_SELECTION_BUFFER_POINTER', `GL_TEXTURE_COORD_ARRAY_POINTER', or `GL_VERTEX_ARRAY_POINTER' are accepted. PARAMS Returns the pointer value specified by PNAME. `glGetPointerv' returns pointer information. PNAME is a symbolic constant indicating the pointer to be returned, and PARAMS is a pointer to a location in which to place the returned data. For all PNAME arguments except `GL_FEEDBACK_BUFFER_POINTER' and `GL_SELECTION_BUFFER_POINTER', if a non-zero named buffer object was bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') when the desired pointer was previously specified, the pointer returned is a byte offset into the buffer object's data store. Buffer objects are only available in OpenGL versions 1.5 and greater. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value.") (define-gl-procedures ((glGetPolygonStipple (pattern GLubyte-*) -> void)) "Return the polygon stipple pattern. PATTERN Returns the stipple pattern. The initial value is all 1's. `glGetPolygonStipple' returns to PATTERN a 32×32 polygon stipple pattern. The pattern is packed into memory as if `glReadPixels' with both HEIGHT and WIDTH of 32, TYPE of `GL_BITMAP', and FORMAT of `GL_COLOR_INDEX' were called, and the stipple pattern were stored in an internal 32×32 color index buffer. Unlike `glReadPixels', however, pixel transfer operations (shift, offset, pixel map) are not applied to the returned stipple image. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a polygon stipple pattern is requested, PATTERN is treated as a byte offset into the buffer object's data store. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glGetPolygonStipple' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetProgramInfoLog (program GLuint) (maxLength GLsizei) (length GLsizei-*) (infoLog GLchar-*) -> void)) "Returns the information log for a program object. PROGRAM Specifies the program object whose information log is to be queried. MAXLENGTH Specifies the size of the character buffer for storing the returned information log. LENGTH Returns the length of the string returned in INFOLOG (excluding the null terminator). INFOLOG Specifies an array of characters that is used to return the information log. `glGetProgramInfoLog' returns the information log for the specified program object. The information log for a program object is modified when the program object is linked or validated. The string that is returned will be null terminated. `glGetProgramInfoLog' returns in INFOLOG as much of the information log as it can, up to a maximum of MAXLENGTH characters. The number of characters actually returned, excluding the null termination character, is specified by LENGTH. If the length of the returned string is not required, a value of `NULL' can be passed in the LENGTH argument. The size of the buffer required to store the returned information log can be obtained by calling `glGetProgram' with the value `GL_INFO_LOG_LENGTH'. The information log for a program object is either an empty string, or a string containing information about the last link operation, or a string containing information about the last validation operation. It may contain diagnostic messages, warning messages, and other information. When a program object is created, its information log will be a string of length 0. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_VALUE' is generated if MAXLENGTH is less than 0. `GL_INVALID_OPERATION' is generated if `glGetProgramInfoLog' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetProgramiv (program GLuint) (pname GLenum) (params GLint-*) -> void)) "Returns a parameter from a program object. PROGRAM Specifies the program object to be queried. PNAME Specifies the object parameter. Accepted symbolic names are `GL_DELETE_STATUS', `GL_LINK_STATUS', `GL_VALIDATE_STATUS', `GL_INFO_LOG_LENGTH', `GL_ATTACHED_SHADERS', `GL_ACTIVE_ATTRIBUTES', `GL_ACTIVE_ATTRIBUTE_MAX_LENGTH', `GL_ACTIVE_UNIFORMS', `GL_ACTIVE_UNIFORM_MAX_LENGTH'. PARAMS Returns the requested object parameter. `glGetProgram' returns in PARAMS the value of a parameter for a specific program object. The following parameters are defined: `GL_DELETE_STATUS' PARAMS returns `GL_TRUE' if PROGRAM is currently flagged for deletion, and `GL_FALSE' otherwise. `GL_LINK_STATUS' PARAMS returns `GL_TRUE' if the last link operation on PROGRAM was successful, and `GL_FALSE' otherwise. `GL_VALIDATE_STATUS' PARAMS returns `GL_TRUE' or if the last validation operation on PROGRAM was successful, and `GL_FALSE' otherwise. `GL_INFO_LOG_LENGTH' PARAMS returns the number of characters in the information log for PROGRAM including the null termination character (i.e., the size of the character buffer required to store the information log). If PROGRAM has no information log, a value of 0 is returned. `GL_ATTACHED_SHADERS' PARAMS returns the number of shader objects attached to PROGRAM. `GL_ACTIVE_ATTRIBUTES' PARAMS returns the number of active attribute variables for PROGRAM. `GL_ACTIVE_ATTRIBUTE_MAX_LENGTH' PARAMS returns the length of the longest active attribute name for PROGRAM, including the null termination character (i.e., the size of the character buffer required to store the longest attribute name). If no active attributes exist, 0 is returned. `GL_ACTIVE_UNIFORMS' PARAMS returns the number of active uniform variables for PROGRAM. `GL_ACTIVE_UNIFORM_MAX_LENGTH' PARAMS returns the length of the longest active uniform variable name for PROGRAM, including the null termination character (i.e., the size of the character buffer required to store the longest uniform variable name). If no active uniform variables exist, 0 is returned. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM does not refer to a program object. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetQueryiv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Return parameters of a query object target. TARGET Specifies a query object target. Must be `GL_SAMPLES_PASSED'. PNAME Specifies the symbolic name of a query object target parameter. Accepted values are `GL_CURRENT_QUERY' or `GL_QUERY_COUNTER_BITS'. PARAMS Returns the requested data. `glGetQueryiv' returns in PARAMS a selected parameter of the query object target specified by TARGET. PNAME names a specific query object target parameter. When TARGET is `GL_SAMPLES_PASSED', PNAME can be as follows: `GL_CURRENT_QUERY' PARAMS returns the name of the currently active occlusion query object. If no occlusion query is active, 0 is returned. The initial value is 0. `GL_QUERY_COUNTER_BITS' PARAMS returns the number of bits in the query counter used to accumulate passing samples. If the number of bits returned is 0, the implementation does not support a query counter, and the results obtained from `glGetQueryObject' are useless. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetQueryiv' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetQueryObjectiv (id GLuint) (pname GLenum) (params GLint-*) -> void) (glGetQueryObjectuiv (id GLuint) (pname GLenum) (params GLuint-*) -> void)) "Return parameters of a query object. ID Specifies the name of a query object. PNAME Specifies the symbolic name of a query object parameter. Accepted values are `GL_QUERY_RESULT' or `GL_QUERY_RESULT_AVAILABLE'. PARAMS Returns the requested data. `glGetQueryObject' returns in PARAMS a selected parameter of the query object specified by ID. PNAME names a specific query object parameter. PNAME can be as follows: `GL_QUERY_RESULT' PARAMS returns the value of the query object's passed samples counter. The initial value is 0. `GL_QUERY_RESULT_AVAILABLE' PARAMS returns whether the passed samples counter is immediately available. If a delay would occur waiting for the query result, `GL_FALSE' is returned. Otherwise, `GL_TRUE' is returned, which also indicates that the results of all previous queries are available as well. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if ID is not the name of a query object. `GL_INVALID_OPERATION' is generated if ID is the name of a currently active query object. `GL_INVALID_OPERATION' is generated if `glGetQueryObject' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetSeparableFilter (target GLenum) (format GLenum) (type GLenum) (row GLvoid-*) (column GLvoid-*) (span GLvoid-*) -> void)) "Get separable convolution filter kernel images. TARGET The separable filter to be retrieved. Must be `GL_SEPARABLE_2D'. FORMAT Format of the output images. Must be one of `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR'`GL_RGBA', `GL_BGRA', `GL_LUMINANCE', or `GL_LUMINANCE_ALPHA'. TYPE Data type of components in the output images. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. ROW Pointer to storage for the row filter image. COLUMN Pointer to storage for the column filter image. SPAN Pointer to storage for the span filter image (currently unused). `glGetSeparableFilter' returns the two one-dimensional filter kernel images for the current separable 2D convolution filter. The row image is placed in ROW and the column image is placed in COLUMN according to the specifications in FORMAT and TYPE. (In the current implementation, SPAN is not affected in any way.) No pixel transfer operations are performed on the images, but the relevant pixel storage modes are applied. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a separable convolution filter is requested, ROW, COLUMN, and SPAN are treated as a byte offset into the buffer object's data store. Color components that are present in FORMAT but not included in the internal format of the filters are returned as zero. The assignments of internal color components to the components of FORMAT are as follows: *Internal Component* *Resulting Component* Red Red Green Green Blue Blue Alpha Alpha Luminance Red Intensity Red `GL_INVALID_ENUM' is generated if TARGET is not `GL_SEPARABLE_2D'. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and ROW or COLUMN is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetSeparableFilter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetShaderInfoLog (shader GLuint) (maxLength GLsizei) (length GLsizei-*) (infoLog GLchar-*) -> void)) "Returns the information log for a shader object. SHADER Specifies the shader object whose information log is to be queried. MAXLENGTH Specifies the size of the character buffer for storing the returned information log. LENGTH Returns the length of the string returned in INFOLOG (excluding the null terminator). INFOLOG Specifies an array of characters that is used to return the information log. `glGetShaderInfoLog' returns the information log for the specified shader object. The information log for a shader object is modified when the shader is compiled. The string that is returned will be null terminated. `glGetShaderInfoLog' returns in INFOLOG as much of the information log as it can, up to a maximum of MAXLENGTH characters. The number of characters actually returned, excluding the null termination character, is specified by LENGTH. If the length of the returned string is not required, a value of `NULL' can be passed in the LENGTH argument. The size of the buffer required to store the returned information log can be obtained by calling `glGetShader' with the value `GL_INFO_LOG_LENGTH'. The information log for a shader object is a string that may contain diagnostic messages, warning messages, and other information about the last compile operation. When a shader object is created, its information log will be a string of length 0. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_VALUE' is generated if MAXLENGTH is less than 0. `GL_INVALID_OPERATION' is generated if `glGetShaderInfoLog' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetShaderSource (shader GLuint) (bufSize GLsizei) (length GLsizei-*) (source GLchar-*) -> void)) "Returns the source code string from a shader object. SHADER Specifies the shader object to be queried. BUFSIZE Specifies the size of the character buffer for storing the returned source code string. LENGTH Returns the length of the string returned in SOURCE (excluding the null terminator). SOURCE Specifies an array of characters that is used to return the source code string. `glGetShaderSource' returns the concatenation of the source code strings from the shader object specified by SHADER. The source code strings for a shader object are the result of a previous call to `glShaderSource'. The string returned by the function will be null terminated. `glGetShaderSource' returns in SOURCE as much of the source code string as it can, up to a maximum of BUFSIZE characters. The number of characters actually returned, excluding the null termination character, is specified by LENGTH. If the length of the returned string is not required, a value of `NULL' can be passed in the LENGTH argument. The size of the buffer required to store the returned source code string can be obtained by calling `glGetShader' with the value `GL_SHADER_SOURCE_LENGTH'. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_VALUE' is generated if BUFSIZE is less than 0. `GL_INVALID_OPERATION' is generated if `glGetShaderSource' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetShaderiv (shader GLuint) (pname GLenum) (params GLint-*) -> void)) "Returns a parameter from a shader object. SHADER Specifies the shader object to be queried. PNAME Specifies the object parameter. Accepted symbolic names are `GL_SHADER_TYPE', `GL_DELETE_STATUS', `GL_COMPILE_STATUS', `GL_INFO_LOG_LENGTH', `GL_SHADER_SOURCE_LENGTH'. PARAMS Returns the requested object parameter. `glGetShader' returns in PARAMS the value of a parameter for a specific shader object. The following parameters are defined: `GL_SHADER_TYPE' PARAMS returns `GL_VERTEX_SHADER' if SHADER is a vertex shader object, and `GL_FRAGMENT_SHADER' if SHADER is a fragment shader object. `GL_DELETE_STATUS' PARAMS returns `GL_TRUE' if SHADER is currently flagged for deletion, and `GL_FALSE' otherwise. `GL_COMPILE_STATUS' PARAMS returns `GL_TRUE' if the last compile operation on SHADER was successful, and `GL_FALSE' otherwise. `GL_INFO_LOG_LENGTH' PARAMS returns the number of characters in the information log for SHADER including the null termination character (i.e., the size of the character buffer required to store the information log). If SHADER has no information log, a value of 0 is returned. `GL_SHADER_SOURCE_LENGTH' PARAMS returns the length of the concatenation of the source strings that make up the shader source for the SHADER, including the null termination character. (i.e., the size of the character buffer required to store the shader source). If no source code exists, 0 is returned. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if SHADER does not refer to a shader object. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetString (name GLenum) -> const-GLubyte*)) "Return a string describing the current GL connection. NAME Specifies a symbolic constant, one of `GL_VENDOR', `GL_RENDERER', `GL_VERSION', `GL_SHADING_LANGUAGE_VERSION', or `GL_EXTENSIONS'. `glGetString' returns a pointer to a static string describing some aspect of the current GL connection. NAME can be one of the following: `GL_VENDOR' Returns the company responsible for this GL implementation. This name does not change from release to release. `GL_RENDERER' Returns the name of the renderer. This name is typically specific to a particular configuration of a hardware platform. It does not change from release to release. `GL_VERSION' Returns a version or release number. `GL_SHADING_LANGUAGE_VERSION' Returns a version or release number for the shading language. `GL_EXTENSIONS' Returns a space-separated list of supported extensions to GL. Because the GL does not include queries for the performance characteristics of an implementation, some applications are written to recognize known platforms and modify their GL usage based on known performance characteristics of these platforms. Strings `GL_VENDOR' and `GL_RENDERER' together uniquely specify a platform. They do not change from release to release and should be used by platform-recognition algorithms. Some applications want to make use of features that are not part of the standard GL. These features may be implemented as extensions to the standard GL. The `GL_EXTENSIONS' string is a space-separated list of supported GL extensions. (Extension names never contain a space character.) The `GL_VERSION' and `GL_SHADING_LANGUAGE_VERSION' strings begin with a version number. The version number uses one of these forms: MAJOR_NUMBER.MINOR_NUMBERMAJOR_NUMBER.MINOR_NUMBER.RELEASE_NUMBER Vendor-specific information may follow the version number. Its format depends on the implementation, but a space always separates the version number and the vendor-specific information. All strings are null-terminated. `GL_INVALID_ENUM' is generated if NAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetString' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetTexEnvfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetTexEnviv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Return texture environment parameters. TARGET Specifies a texture environment. May be `GL_TEXTURE_ENV', `GL_TEXTURE_FILTER_CONTROL', or `GL_POINT_SPRITE'. PNAME Specifies the symbolic name of a texture environment parameter. Accepted values are `GL_TEXTURE_ENV_MODE', `GL_TEXTURE_ENV_COLOR', `GL_TEXTURE_LOD_BIAS', `GL_COMBINE_RGB', `GL_COMBINE_ALPHA', `GL_SRC0_RGB', `GL_SRC1_RGB', `GL_SRC2_RGB', `GL_SRC0_ALPHA', `GL_SRC1_ALPHA', `GL_SRC2_ALPHA', `GL_OPERAND0_RGB', `GL_OPERAND1_RGB', `GL_OPERAND2_RGB', `GL_OPERAND0_ALPHA', `GL_OPERAND1_ALPHA', `GL_OPERAND2_ALPHA', `GL_RGB_SCALE', `GL_ALPHA_SCALE', or `GL_COORD_REPLACE'. PARAMS Returns the requested data. `glGetTexEnv' returns in PARAMS selected values of a texture environment that was specified with `glTexEnv'. TARGET specifies a texture environment. When TARGET is `GL_TEXTURE_FILTER_CONTROL', PNAME must be `GL_TEXTURE_LOD_BIAS'. When TARGET is `GL_POINT_SPRITE', PNAME must be `GL_COORD_REPLACE'. When TARGET is `GL_TEXTURE_ENV', PNAME can be `GL_TEXTURE_ENV_MODE', `GL_TEXTURE_ENV_COLOR', `GL_COMBINE_RGB', `GL_COMBINE_ALPHA', `GL_RGB_SCALE', `GL_ALPHA_SCALE', `GL_SRC0_RGB', `GL_SRC1_RGB', `GL_SRC2_RGB', `GL_SRC0_ALPHA', `GL_SRC1_ALPHA', or `GL_SRC2_ALPHA'. PNAME names a specific texture environment parameter, as follows: `GL_TEXTURE_ENV_MODE' PARAMS returns the single-valued texture environment mode, a symbolic constant. The initial value is `GL_MODULATE'. `GL_TEXTURE_ENV_COLOR' PARAMS returns four integer or floating-point values that are the texture environment color. Integer values, when requested, are linearly mapped from the internal floating-point representation such that 1.0 maps to the most positive representable integer, and -1.0 maps to the most negative representable integer. The initial value is (0, 0, 0, 0). `GL_TEXTURE_LOD_BIAS' PARAMS returns a single floating-point value that is the texture level-of-detail bias. The initial value is 0. `GL_COMBINE_RGB' PARAMS returns a single symbolic constant value representing the current RGB combine mode. The initial value is `GL_MODULATE'. `GL_COMBINE_ALPHA' PARAMS returns a single symbolic constant value representing the current alpha combine mode. The initial value is `GL_MODULATE'. `GL_SRC0_RGB' PARAMS returns a single symbolic constant value representing the texture combiner zero's RGB source. The initial value is `GL_TEXTURE'. `GL_SRC1_RGB' PARAMS returns a single symbolic constant value representing the texture combiner one's RGB source. The initial value is `GL_PREVIOUS'. `GL_SRC2_RGB' PARAMS returns a single symbolic constant value representing the texture combiner two's RGB source. The initial value is `GL_CONSTANT'. `GL_SRC0_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner zero's alpha source. The initial value is `GL_TEXTURE'. `GL_SRC1_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner one's alpha source. The initial value is `GL_PREVIOUS'. `GL_SRC2_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner two's alpha source. The initial value is `GL_CONSTANT'. `GL_OPERAND0_RGB' PARAMS returns a single symbolic constant value representing the texture combiner zero's RGB operand. The initial value is `GL_SRC_COLOR'. `GL_OPERAND1_RGB' PARAMS returns a single symbolic constant value representing the texture combiner one's RGB operand. The initial value is `GL_SRC_COLOR'. `GL_OPERAND2_RGB' PARAMS returns a single symbolic constant value representing the texture combiner two's RGB operand. The initial value is `GL_SRC_ALPHA'. `GL_OPERAND0_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner zero's alpha operand. The initial value is `GL_SRC_ALPHA'. `GL_OPERAND1_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner one's alpha operand. The initial value is `GL_SRC_ALPHA'. `GL_OPERAND2_ALPHA' PARAMS returns a single symbolic constant value representing the texture combiner two's alpha operand. The initial value is `GL_SRC_ALPHA'. `GL_RGB_SCALE' PARAMS returns a single floating-point value representing the current RGB texture combiner scaling factor. The initial value is 1.0. `GL_ALPHA_SCALE' PARAMS returns a single floating-point value representing the current alpha texture combiner scaling factor. The initial value is 1.0. `GL_COORD_REPLACE' PARAMS returns a single boolean value representing the current point sprite texture coordinate replacement enable state. The initial value is `GL_FALSE'. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetTexEnv' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetTexGenfv (coord GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetTexGeniv (coord GLenum) (pname GLenum) (params GLint-*) -> void)) "Return texture coordinate generation parameters. COORD Specifies a texture coordinate. Must be `GL_S', `GL_T', `GL_R', or `GL_Q'. PNAME Specifies the symbolic name of the value(s) to be returned. Must be either `GL_TEXTURE_GEN_MODE' or the name of one of the texture generation plane equations: `GL_OBJECT_PLANE' or `GL_EYE_PLANE'. PARAMS Returns the requested data. `glGetTexGen' returns in PARAMS selected parameters of a texture coordinate generation function that was specified using `glTexGen'. COORD names one of the (S, T, R, Q) texture coordinates, using the symbolic constant `GL_S', `GL_T', `GL_R', or `GL_Q'. PNAME specifies one of three symbolic names: `GL_TEXTURE_GEN_MODE' PARAMS returns the single-valued texture generation function, a symbolic constant. The initial value is `GL_EYE_LINEAR'. `GL_OBJECT_PLANE' PARAMS returns the four plane equation coefficients that specify object linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation. `GL_EYE_PLANE' PARAMS returns the four plane equation coefficients that specify eye linear-coordinate generation. Integer values, when requested, are mapped directly from the internal floating-point representation. The returned values are those maintained in eye coordinates. They are not equal to the values specified using `glTexGen', unless the modelview matrix was identity when `glTexGen' was called. `GL_INVALID_ENUM' is generated if COORD or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetTexGen' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetTexImage (target GLenum) (level GLint) (format GLenum) (type GLenum) (img GLvoid-*) -> void)) "Return a texture image. TARGET Specifies which texture is to be obtained. `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', and `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z' are accepted. LEVEL Specifies the level-of-detail number of the desired image. Level 0 is the base image level. Level N is the N th mipmap reduction image. FORMAT Specifies a pixel format for the returned data. The supported formats are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies a pixel type for the returned data. The supported types are `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. IMG Returns the texture image. Should be a pointer to an array of the type specified by TYPE. `glGetTexImage' returns a texture image into IMG. TARGET specifies whether the desired texture image is one specified by `glTexImage1D' (`GL_TEXTURE_1D'), `glTexImage2D' (`GL_TEXTURE_2D' or any of `GL_TEXTURE_CUBE_MAP_*'), or `glTexImage3D' (`GL_TEXTURE_3D'). LEVEL specifies the level-of-detail number of the desired image. FORMAT and TYPE specify the format and type of the desired image array. See the reference pages `glTexImage1D' and `glDrawPixels' for a description of the acceptable values for the FORMAT and TYPE parameters, respectively. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a texture image is requested, IMG is treated as a byte offset into the buffer object's data store. To understand the operation of `glGetTexImage', consider the selected internal four-component texture image to be an RGBA color buffer the size of the image. The semantics of `glGetTexImage' are then identical to those of `glReadPixels', with the exception that no pixel transfer operations are performed, when called with the same FORMAT and TYPE, with X and Y set to 0, WIDTH set to the width of the texture image (including border if one was specified), and HEIGHT set to 1 for 1D images, or to the height of the texture image (including border if one was specified) for 2D images. Because the internal texture image is an RGBA image, pixel formats `GL_COLOR_INDEX', `GL_STENCIL_INDEX', and `GL_DEPTH_COMPONENT' are not accepted, and pixel type `GL_BITMAP' is not accepted. If the selected texture image does not contain four components, the following mappings are applied. Single-component textures are treated as RGBA buffers with red set to the single-component value, green set to 0, blue set to 0, and alpha set to 1. Two-component textures are treated as RGBA buffers with red set to the value of component zero, alpha set to the value of component one, and green and blue set to 0. Finally, three-component textures are treated as RGBA buffers with red set to component zero, green set to component one, blue set to component two, and alpha set to 1. To determine the required size of IMG, use `glGetTexLevelParameter' to determine the dimensions of the internal texture image, then scale the required number of pixels by the storage required for each pixel, based on FORMAT and TYPE. Be sure to take the pixel storage parameters into account, especially `GL_PACK_ALIGNMENT'. `GL_INVALID_ENUM' is generated if TARGET, FORMAT, or TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_OPERATION' is returned if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is returned if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV', and FORMAT is neither `GL_RGBA' or `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and the data would be packed to the buffer object such that the memory writes required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_PACK_BUFFER' target and IMG is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glGetTexImage' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetTexLevelParameterfv (target GLenum) (level GLint) (pname GLenum) (params GLfloat-*) -> void) (glGetTexLevelParameteriv (target GLenum) (level GLint) (pname GLenum) (params GLint-*) -> void)) "Return texture parameter values for a specific level of detail. TARGET Specifies the symbolic name of the target texture, either `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', `GL_PROXY_TEXTURE_1D', `GL_PROXY_TEXTURE_2D', `GL_PROXY_TEXTURE_3D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z', or `GL_PROXY_TEXTURE_CUBE_MAP'. LEVEL Specifies the level-of-detail number of the desired image. Level 0 is the base image level. Level N is the N th mipmap reduction image. PNAME Specifies the symbolic name of a texture parameter. `GL_TEXTURE_WIDTH', `GL_TEXTURE_HEIGHT', `GL_TEXTURE_DEPTH', `GL_TEXTURE_INTERNAL_FORMAT', `GL_TEXTURE_BORDER', `GL_TEXTURE_RED_SIZE', `GL_TEXTURE_GREEN_SIZE', `GL_TEXTURE_BLUE_SIZE', `GL_TEXTURE_ALPHA_SIZE', `GL_TEXTURE_LUMINANCE_SIZE', `GL_TEXTURE_INTENSITY_SIZE', `GL_TEXTURE_DEPTH_SIZE', `GL_TEXTURE_COMPRESSED', and `GL_TEXTURE_COMPRESSED_IMAGE_SIZE' are accepted. PARAMS Returns the requested data. `glGetTexLevelParameter' returns in PARAMS texture parameter values for a specific level-of-detail value, specified as LEVEL. TARGET defines the target texture, either `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', `GL_PROXY_TEXTURE_1D', `GL_PROXY_TEXTURE_2D', `GL_PROXY_TEXTURE_3D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z', or `GL_PROXY_TEXTURE_CUBE_MAP'. `GL_MAX_TEXTURE_SIZE', and `GL_MAX_3D_TEXTURE_SIZE' are not really descriptive enough. It has to report the largest square texture image that can be accommodated with mipmaps and borders, but a long skinny texture, or a texture without mipmaps and borders, may easily fit in texture memory. The proxy targets allow the user to more accurately query whether the GL can accommodate a texture of a given configuration. If the texture cannot be accommodated, the texture state variables, which may be queried with `glGetTexLevelParameter', are set to 0. If the texture can be accommodated, the texture state values will be set as they would be set for a non-proxy target. PNAME specifies the texture parameter whose value or values will be returned. The accepted parameter names are as follows: `GL_TEXTURE_WIDTH' PARAMS returns a single value, the width of the texture image. This value includes the border of the texture image. The initial value is 0. `GL_TEXTURE_HEIGHT' PARAMS returns a single value, the height of the texture image. This value includes the border of the texture image. The initial value is 0. `GL_TEXTURE_DEPTH' PARAMS returns a single value, the depth of the texture image. This value includes the border of the texture image. The initial value is 0. `GL_TEXTURE_INTERNAL_FORMAT' PARAMS returns a single value, the internal format of the texture image. `GL_TEXTURE_BORDER' PARAMS returns a single value, the width in pixels of the border of the texture image. The initial value is 0. `GL_TEXTURE_RED_SIZE', `GL_TEXTURE_GREEN_SIZE', `GL_TEXTURE_BLUE_SIZE', `GL_TEXTURE_ALPHA_SIZE', `GL_TEXTURE_LUMINANCE_SIZE', `GL_TEXTURE_INTENSITY_SIZE', `GL_TEXTURE_DEPTH_SIZE' The internal storage resolution of an individual component. The resolution chosen by the GL will be a close match for the resolution requested by the user with the component argument of `glTexImage1D', `glTexImage2D', `glTexImage3D', `glCopyTexImage1D', and `glCopyTexImage2D'. The initial value is 0. `GL_TEXTURE_COMPRESSED' PARAMS returns a single boolean value indicating if the texture image is stored in a compressed internal format. The initiali value is `GL_FALSE'. `GL_TEXTURE_COMPRESSED_IMAGE_SIZE' PARAMS returns a single integer value, the number of unsigned bytes of the compressed texture image that would be returned from `glGetCompressedTexImage'. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an accepted value. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2 MAX, where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_OPERATION' is generated if `glGetTexLevelParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if `GL_TEXTURE_COMPRESSED_IMAGE_SIZE' is queried on texture images with an uncompressed internal format or on proxy targets.") (define-gl-procedures ((glGetTexParameterfv (target GLenum) (pname GLenum) (params GLfloat-*) -> void) (glGetTexParameteriv (target GLenum) (pname GLenum) (params GLint-*) -> void)) "Return texture parameter values. TARGET Specifies the symbolic name of the target texture. `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', and `GL_TEXTURE_CUBE_MAP' are accepted. PNAME Specifies the symbolic name of a texture parameter. `GL_TEXTURE_MAG_FILTER', `GL_TEXTURE_MIN_FILTER', `GL_TEXTURE_MIN_LOD', `GL_TEXTURE_MAX_LOD', `GL_TEXTURE_BASE_LEVEL', `GL_TEXTURE_MAX_LEVEL', `GL_TEXTURE_WRAP_S', `GL_TEXTURE_WRAP_T', `GL_TEXTURE_WRAP_R', `GL_TEXTURE_BORDER_COLOR', `GL_TEXTURE_PRIORITY', `GL_TEXTURE_RESIDENT', `GL_TEXTURE_COMPARE_MODE', `GL_TEXTURE_COMPARE_FUNC', `GL_DEPTH_TEXTURE_MODE', and `GL_GENERATE_MIPMAP' are accepted. PARAMS Returns the texture parameters. `glGetTexParameter' returns in PARAMS the value or values of the texture parameter specified as PNAME. TARGET defines the target texture, either `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', or `GL_TEXTURE_CUBE_MAP', to specify one-, two-, or three-dimensional or cube-mapped texturing. PNAME accepts the same symbols as `glTexParameter', with the same interpretations: `GL_TEXTURE_MAG_FILTER' Returns the single-valued texture magnification filter, a symbolic constant. The initial value is `GL_LINEAR'. `GL_TEXTURE_MIN_FILTER' Returns the single-valued texture minification filter, a symbolic constant. The initial value is `GL_NEAREST_MIPMAP_LINEAR'. `GL_TEXTURE_MIN_LOD' Returns the single-valued texture minimum level-of-detail value. The initial value is -1000 . `GL_TEXTURE_MAX_LOD' Returns the single-valued texture maximum level-of-detail value. The initial value is 1000. `GL_TEXTURE_BASE_LEVEL' Returns the single-valued base texture mipmap level. The initial value is 0. `GL_TEXTURE_MAX_LEVEL' Returns the single-valued maximum texture mipmap array level. The initial value is 1000. `GL_TEXTURE_WRAP_S' Returns the single-valued wrapping function for texture coordinate S , a symbolic constant. The initial value is `GL_REPEAT'. `GL_TEXTURE_WRAP_T' Returns the single-valued wrapping function for texture coordinate T , a symbolic constant. The initial value is `GL_REPEAT'. `GL_TEXTURE_WRAP_R' Returns the single-valued wrapping function for texture coordinate R , a symbolic constant. The initial value is `GL_REPEAT'. `GL_TEXTURE_BORDER_COLOR' Returns four integer or floating-point numbers that comprise the RGBA color of the texture border. Floating-point values are returned in the range [0,1] . Integer values are returned as a linear mapping of the internal floating-point representation such that 1.0 maps to the most positive representable integer and -1.0 maps to the most negative representable integer. The initial value is (0, 0, 0, 0). `GL_TEXTURE_PRIORITY' Returns the residence priority of the target texture (or the named texture bound to it). The initial value is 1. See `glPrioritizeTextures'. `GL_TEXTURE_RESIDENT' Returns the residence status of the target texture. If the value returned in PARAMS is `GL_TRUE', the texture is resident in texture memory. See `glAreTexturesResident'. `GL_TEXTURE_COMPARE_MODE' Returns a single-valued texture comparison mode, a symbolic constant. The initial value is `GL_NONE'. See `glTexParameter'. `GL_TEXTURE_COMPARE_FUNC' Returns a single-valued texture comparison function, a symbolic constant. The initial value is `GL_LEQUAL'. See `glTexParameter'. `GL_DEPTH_TEXTURE_MODE' Returns a single-valued texture format indicating how the depth values should be converted into color components. The initial value is `GL_LUMINANCE'. See `glTexParameter'. `GL_GENERATE_MIPMAP' Returns a single boolean value indicating if automatic mipmap level updates are enabled. See `glTexParameter'. `GL_INVALID_ENUM' is generated if TARGET or PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGetTexParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetUniformLocation (program GLuint) (name const-GLchar-*) -> GLint)) "Returns the location of a uniform variable. PROGRAM Specifies the program object to be queried. NAME Points to a null terminated string containing the name of the uniform variable whose location is to be queried. `glGetUniformLocation ' returns an integer that represents the location of a specific uniform variable within a program object. NAME must be a null terminated string that contains no white space. NAME must be an active uniform variable name in PROGRAM that is not a structure, an array of structures, or a subcomponent of a vector or a matrix. This function returns -1 if NAME does not correspond to an active uniform variable in PROGRAM or if NAME starts with the reserved prefix \"gl_\". Uniform variables that are structures or arrays of structures may be queried by calling `glGetUniformLocation' for each field within the structure. The array element operator \"[]\" and the structure field operator \".\" may be used in NAME in order to select elements within an array or fields within a structure. The result of using these operators is not allowed to be another structure, an array of structures, or a subcomponent of a vector or a matrix. Except if the last part of NAME indicates a uniform variable array, the location of the first element of an array can be retrieved by using the name of the array, or by using the name appended by \"[0]\". The actual locations assigned to uniform variables are not known until the program object is linked successfully. After linking has occurred, the command `glGetUniformLocation' can be used to obtain the location of a uniform variable. This location value can then be passed to `glUniform' to set the value of the uniform variable or to `glGetUniform' in order to query the current value of the uniform variable. After a program object has been linked successfully, the index values for uniform variables remain fixed until the next link command occurs. Uniform variable locations and values can only be queried after a link if the link was successful. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if PROGRAM has not been successfully linked. `GL_INVALID_OPERATION' is generated if `glGetUniformLocation' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetUniformfv (program GLuint) (location GLint) (params GLfloat-*) -> void) (glGetUniformiv (program GLuint) (location GLint) (params GLint-*) -> void)) "Returns the value of a uniform variable. PROGRAM Specifies the program object to be queried. LOCATION Specifies the location of the uniform variable to be queried. PARAMS Returns the value of the specified uniform variable. `glGetUniform' returns in PARAMS the value(s) of the specified uniform variable. The type of the uniform variable specified by LOCATION determines the number of values returned. If the uniform variable is defined in the shader as a boolean, int, or float, a single value will be returned. If it is defined as a vec2, ivec2, or bvec2, two values will be returned. If it is defined as a vec3, ivec3, or bvec3, three values will be returned, and so on. To query values stored in uniform variables declared as arrays, call `glGetUniform' for each element of the array. To query values stored in uniform variables declared as structures, call `glGetUniform' for each field in the structure. The values for uniform variables declared as a matrix will be returned in column major order. The locations assigned to uniform variables are not known until the program object is linked. After linking has occurred, the command `glGetUniformLocation' can be used to obtain the location of a uniform variable. This location value can then be passed to `glGetUniform' in order to query the current value of the uniform variable. After a program object has been linked successfully, the index values for uniform variables remain fixed until the next link command occurs. The uniform variable values can only be queried after a link if the link was successful. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if PROGRAM has not been successfully linked. `GL_INVALID_OPERATION' is generated if LOCATION does not correspond to a valid uniform variable location for the specified program object. `GL_INVALID_OPERATION' is generated if `glGetUniform' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glGetVertexAttribPointerv (index GLuint) (pname GLenum) (pointer GLvoid-**) -> void)) "Return the address of the specified generic vertex attribute pointer. INDEX Specifies the generic vertex attribute parameter to be returned. PNAME Specifies the symbolic name of the generic vertex attribute parameter to be returned. Must be `GL_VERTEX_ATTRIB_ARRAY_POINTER'. POINTER Returns the pointer value. `glGetVertexAttribPointerv' returns pointer information. INDEX is the generic vertex attribute to be queried, PNAME is a symbolic constant indicating the pointer to be returned, and PARAMS is a pointer to a location in which to place the returned data. If a non-zero named buffer object was bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') when the desired pointer was previously specified, the POINTER returned is a byte offset into the buffer object's data store. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value.") (define-gl-procedures ((glGetVertexAttribfv (index GLuint) (pname GLenum) (params GLfloat-*) -> void) (glGetVertexAttribiv (index GLuint) (pname GLenum) (params GLint-*) -> void)) "Return a generic vertex attribute parameter. INDEX Specifies the generic vertex attribute parameter to be queried. PNAME Specifies the symbolic name of the vertex attribute parameter to be queried. Accepted values are `GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING', `GL_VERTEX_ATTRIB_ARRAY_ENABLED', `GL_VERTEX_ATTRIB_ARRAY_SIZE', `GL_VERTEX_ATTRIB_ARRAY_STRIDE', `GL_VERTEX_ATTRIB_ARRAY_TYPE', `GL_VERTEX_ATTRIB_ARRAY_NORMALIZED', or `GL_CURRENT_VERTEX_ATTRIB'. PARAMS Returns the requested data. `glGetVertexAttrib' returns in PARAMS the value of a generic vertex attribute parameter. The generic vertex attribute to be queried is specified by INDEX, and the parameter to be queried is specified by PNAME. The accepted parameter names are as follows: `GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object currently bound to the binding point corresponding to generic vertex attribute array INDEX. If no buffer object is bound, 0 is returned. The initial value is 0. `GL_VERTEX_ATTRIB_ARRAY_ENABLED' PARAMS returns a single value that is non-zero (true) if the vertex attribute array for INDEX is enabled and 0 (false) if it is disabled. The initial value is `GL_FALSE'. `GL_VERTEX_ATTRIB_ARRAY_SIZE' PARAMS returns a single value, the size of the vertex attribute array for INDEX. The size is the number of values for each element of the vertex attribute array, and it will be 1, 2, 3, or 4. The initial value is 4. `GL_VERTEX_ATTRIB_ARRAY_STRIDE' PARAMS returns a single value, the array stride for (number of bytes between successive elements in) the vertex attribute array for INDEX. A value of 0 indicates that the array elements are stored sequentially in memory. The initial value is 0. `GL_VERTEX_ATTRIB_ARRAY_TYPE' PARAMS returns a single value, a symbolic constant indicating the array type for the vertex attribute array for INDEX. Possible values are `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', and `GL_DOUBLE'. The initial value is `GL_FLOAT'. `GL_VERTEX_ATTRIB_ARRAY_NORMALIZED' PARAMS returns a single value that is non-zero (true) if fixed-point data types for the vertex attribute array indicated by INDEX are normalized when they are converted to floating point, and 0 (false) otherwise. The initial value is `GL_FALSE'. `GL_CURRENT_VERTEX_ATTRIB' PARAMS returns four values that represent the current value for the generic vertex attribute specified by index. Generic vertex attribute 0 is unique in that it has no current state, so an error will be generated if INDEX is 0. The initial value for all other generic vertex attributes is (0,0,0,1). All of the parameters except `GL_CURRENT_VERTEX_ATTRIB' represent client-side state. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if INDEX is 0 and PNAME is `GL_CURRENT_VERTEX_ATTRIB'.") (define-gl-procedures ((glGetBooleanv (pname GLenum) (params GLboolean-*) -> void) (glGetDoublev (pname GLenum) (params GLdouble-*) -> void) (glGetFloatv (pname GLenum) (params GLfloat-*) -> void) (glGetIntegerv (pname GLenum) (params GLint-*) -> void)) "Return the value or values of a selected parameter. PNAME Specifies the parameter value to be returned. The symbolic constants in the list below are accepted. PARAMS Returns the value or values of the specified parameter. These four commands return values for simple state variables in GL. PNAME is a symbolic constant indicating the state variable to be returned, and PARAMS is a pointer to an array of the indicated type in which to place the returned data. Type conversion is performed if PARAMS has a different type than the state variable value being requested. If `glGetBooleanv' is called, a floating-point (or integer) value is converted to `GL_FALSE' if and only if it is 0.0 (or 0). Otherwise, it is converted to `GL_TRUE'. If `glGetIntegerv' is called, boolean values are returned as `GL_TRUE' or `GL_FALSE', and most floating-point values are rounded to the nearest integer value. Floating-point colors and normals, however, are returned with a linear mapping that maps 1.0 to the most positive representable integer value and -1.0 to the most negative representable integer value. If `glGetFloatv' or `glGetDoublev' is called, boolean values are returned as `GL_TRUE' or `GL_FALSE', and integer values are converted to floating-point values. The following symbolic constants are accepted by PNAME: `GL_ACCUM_ALPHA_BITS' PARAMS returns one value, the number of alpha bitplanes in the accumulation buffer. `GL_ACCUM_BLUE_BITS' PARAMS returns one value, the number of blue bitplanes in the accumulation buffer. `GL_ACCUM_CLEAR_VALUE' PARAMS returns four values: the red, green, blue, and alpha values used to clear the accumulation buffer. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 0, 0). See `glClearAccum'. `GL_ACCUM_GREEN_BITS' PARAMS returns one value, the number of green bitplanes in the accumulation buffer. `GL_ACCUM_RED_BITS' PARAMS returns one value, the number of red bitplanes in the accumulation buffer. `GL_ACTIVE_TEXTURE' PARAMS returns a single value indicating the active multitexture unit. The initial value is `GL_TEXTURE0'. See `glActiveTexture'. `GL_ALIASED_POINT_SIZE_RANGE' PARAMS returns two values, the smallest and largest supported sizes for aliased points. `GL_ALIASED_LINE_WIDTH_RANGE' PARAMS returns two values, the smallest and largest supported widths for aliased lines. `GL_ALPHA_BIAS' PARAMS returns one value, the alpha bias factor used during pixel transfers. The initial value is 0. See `glPixelTransfer'. `GL_ALPHA_BITS' PARAMS returns one value, the number of alpha bitplanes in each color buffer. `GL_ALPHA_SCALE' PARAMS returns one value, the alpha scale factor used during pixel transfers. The initial value is 1. See `glPixelTransfer'. `GL_ALPHA_TEST' PARAMS returns a single boolean value indicating whether alpha testing of fragments is enabled. The initial value is `GL_FALSE'. See `glAlphaFunc'. `GL_ALPHA_TEST_FUNC'PARAMS returns one value, the symbolic name of the alpha test function. The initial value is `GL_ALWAYS'. See `glAlphaFunc'. `GL_ALPHA_TEST_REF' PARAMS returns one value, the reference value for the alpha test. The initial value is 0. See `glAlphaFunc'. An integer value, if requested, is linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. `GL_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object currently bound to the target `GL_ARRAY_BUFFER'. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_ATTRIB_STACK_DEPTH' PARAMS returns one value, the depth of the attribute stack. If the stack is empty, 0 is returned. The initial value is 0. See `glPushAttrib'. `GL_AUTO_NORMAL' PARAMS returns a single boolean value indicating whether 2D map evaluation automatically generates surface normals. The initial value is `GL_FALSE'. See `glMap2'. `GL_AUX_BUFFERS' PARAMS returns one value, the number of auxiliary color buffers available. `GL_BLEND' PARAMS returns a single boolean value indicating whether blending is enabled. The initial value is `GL_FALSE'. See `glBlendFunc'. `GL_BLEND_COLOR' PARAMS returns four values, the red, green, blue, and alpha values which are the components of the blend color. See `glBlendColor'. `GL_BLEND_DST_ALPHA' PARAMS returns one value, the symbolic constant identifying the alpha destination blend function. The initial value is `GL_ZERO'. See `glBlendFunc' and `glBlendFuncSeparate'. `GL_BLEND_DST_RGB' PARAMS returns one value, the symbolic constant identifying the RGB destination blend function. The initial value is `GL_ZERO'. See `glBlendFunc' and `glBlendFuncSeparate'. `GL_BLEND_EQUATION_RGB' PARAMS returns one value, a symbolic constant indicating whether the RGB blend equation is `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MIN' or `GL_MAX'. See `glBlendEquationSeparate'. `GL_BLEND_EQUATION_ALPHA' PARAMS returns one value, a symbolic constant indicating whether the Alpha blend equation is `GL_FUNC_ADD', `GL_FUNC_SUBTRACT', `GL_FUNC_REVERSE_SUBTRACT', `GL_MIN' or `GL_MAX'. See `glBlendEquationSeparate'. `GL_BLEND_SRC_ALPHA' PARAMS returns one value, the symbolic constant identifying the alpha source blend function. The initial value is `GL_ONE'. See `glBlendFunc' and `glBlendFuncSeparate'. `GL_BLEND_SRC_RGB' PARAMS returns one value, the symbolic constant identifying the RGB source blend function. The initial value is `GL_ONE'. See `glBlendFunc' and `glBlendFuncSeparate'. `GL_BLUE_BIAS' PARAMS returns one value, the blue bias factor used during pixel transfers. The initial value is 0. See `glPixelTransfer'. `GL_BLUE_BITS' PARAMS returns one value, the number of blue bitplanes in each color buffer. `GL_BLUE_SCALE' PARAMS returns one value, the blue scale factor used during pixel transfers. The initial value is 1. See `glPixelTransfer'. `GL_CLIENT_ACTIVE_TEXTURE' PARAMS returns a single integer value indicating the current client active multitexture unit. The initial value is `GL_TEXTURE0'. See `glClientActiveTexture'. `GL_CLIENT_ATTRIB_STACK_DEPTH' PARAMS returns one value indicating the depth of the attribute stack. The initial value is 0. See `glPushClientAttrib'. `GL_CLIP_PLANE'I PARAMS returns a single boolean value indicating whether the specified clipping plane is enabled. The initial value is `GL_FALSE'. See `glClipPlane'. `GL_COLOR_ARRAY' PARAMS returns a single boolean value indicating whether the color array is enabled. The initial value is `GL_FALSE'. See `glColorPointer'. `GL_COLOR_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the color array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glColorPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_COLOR_ARRAY_SIZE' PARAMS returns one value, the number of components per color in the color array. The initial value is 4. See `glColorPointer'. `GL_COLOR_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive colors in the color array. The initial value is 0. See `glColorPointer'. `GL_COLOR_ARRAY_TYPE' PARAMS returns one value, the data type of each component in the color array. The initial value is `GL_FLOAT'. See `glColorPointer'. `GL_COLOR_CLEAR_VALUE' PARAMS returns four values: the red, green, blue, and alpha values used to clear the color buffers. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 0, 0). See `glClearColor'. `GL_COLOR_LOGIC_OP' PARAMS returns a single boolean value indicating whether a fragment's RGBA color values are merged into the framebuffer using a logical operation. The initial value is `GL_FALSE'. See `glLogicOp'. `GL_COLOR_MATERIAL' PARAMS returns a single boolean value indicating whether one or more material parameters are tracking the current color. The initial value is `GL_FALSE'. See `glColorMaterial'. `GL_COLOR_MATERIAL_FACE' PARAMS returns one value, a symbolic constant indicating which materials have a parameter that is tracking the current color. The initial value is `GL_FRONT_AND_BACK'. See `glColorMaterial'. `GL_COLOR_MATERIAL_PARAMETER' PARAMS returns one value, a symbolic constant indicating which material parameters are tracking the current color. The initial value is `GL_AMBIENT_AND_DIFFUSE'. See `glColorMaterial'. `GL_COLOR_MATRIX' PARAMS returns sixteen values: the color matrix on the top of the color matrix stack. Initially this matrix is the identity matrix. See `glPushMatrix'. `GL_COLOR_MATRIX_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the projection matrix stack. The value must be at least 2. See `glPushMatrix'. `GL_COLOR_SUM' PARAMS returns a single boolean value indicating whether primary and secondary color sum is enabled. See `glSecondaryColor'. `GL_COLOR_TABLE' PARAMS returns a single boolean value indicating whether the color table lookup is enabled. See `glColorTable'. `GL_COLOR_WRITEMASK' PARAMS returns four boolean values: the red, green, blue, and alpha write enables for the color buffers. The initial value is (`GL_TRUE', `GL_TRUE', `GL_TRUE', `GL_TRUE'). See `glColorMask'. `GL_COMPRESSED_TEXTURE_FORMATS' PARAMS returns a list of symbolic constants of length `GL_NUM_COMPRESSED_TEXTURE_FORMATS' indicating which compressed texture formats are available. See `glCompressedTexImage2D'. `GL_CONVOLUTION_1D' PARAMS returns a single boolean value indicating whether 1D convolution is enabled. The initial value is `GL_FALSE'. See `glConvolutionFilter1D'. `GL_CONVOLUTION_2D' PARAMS returns a single boolean value indicating whether 2D convolution is enabled. The initial value is `GL_FALSE'. See `glConvolutionFilter2D'. `GL_CULL_FACE' PARAMS returns a single boolean value indicating whether polygon culling is enabled. The initial value is `GL_FALSE'. See `glCullFace'. `GL_CULL_FACE_MODE' PARAMS returns one value, a symbolic constant indicating which polygon faces are to be culled. The initial value is `GL_BACK'. See `glCullFace'. `GL_CURRENT_COLOR' PARAMS returns four values: the red, green, blue, and alpha values of the current color. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (1, 1, 1, 1). See `glColor'. `GL_CURRENT_FOG_COORD' PARAMS returns one value, the current fog coordinate. The initial value is 0. See `glFogCoord'. `GL_CURRENT_INDEX' PARAMS returns one value, the current color index. The initial value is 1. See `glIndex'. `GL_CURRENT_NORMAL' PARAMS returns three values: the X, Y, and Z values of the current normal. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 1). See `glNormal'. `GL_CURRENT_PROGRAM' PARAMS returns one value, the name of the program object that is currently active, or 0 if no program object is active. See `glUseProgram'. `GL_CURRENT_RASTER_COLOR' PARAMS returns four values: the red, green, blue, and alpha color values of the current raster position. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (1, 1, 1, 1). See `glRasterPos'. `GL_CURRENT_RASTER_DISTANCE' PARAMS returns one value, the distance from the eye to the current raster position. The initial value is 0. See `glRasterPos'. `GL_CURRENT_RASTER_INDEX' PARAMS returns one value, the color index of the current raster position. The initial value is 1. See `glRasterPos'. `GL_CURRENT_RASTER_POSITION' PARAMS returns four values: the X, Y, Z, and W components of the current raster position. X, Y, and Z are in window coordinates, and W is in clip coordinates. The initial value is (0, 0, 0, 1). See `glRasterPos'. `GL_CURRENT_RASTER_POSITION_VALID' PARAMS returns a single boolean value indicating whether the current raster position is valid. The initial value is `GL_TRUE'. See `glRasterPos'. `GL_CURRENT_RASTER_SECONDARY_COLOR' PARAMS returns four values: the red, green, blue, and alpha secondary color values of the current raster position. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (1, 1, 1, 1). See `glRasterPos'. `GL_CURRENT_RASTER_TEXTURE_COORDS' PARAMS returns four values: the S, T, R, and Q texture coordinates of the current raster position. The initial value is (0, 0, 0, 1). See `glRasterPos' and `glMultiTexCoord'. `GL_CURRENT_SECONDARY_COLOR' PARAMS returns four values: the red, green, blue, and alpha values of the current secondary color. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 0, 0). See `glSecondaryColor'. `GL_CURRENT_TEXTURE_COORDS' PARAMS returns four values: the S, T, R, and Q current texture coordinates. The initial value is (0, 0, 0, 1). See `glMultiTexCoord'. `GL_DEPTH_BIAS' PARAMS returns one value, the depth bias factor used during pixel transfers. The initial value is 0. See `glPixelTransfer'. `GL_DEPTH_BITS' PARAMS returns one value, the number of bitplanes in the depth buffer. `GL_DEPTH_CLEAR_VALUE' PARAMS returns one value, the value that is used to clear the depth buffer. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is 1. See `glClearDepth'. `GL_DEPTH_FUNC' PARAMS returns one value, the symbolic constant that indicates the depth comparison function. The initial value is `GL_LESS'. See `glDepthFunc'. `GL_DEPTH_RANGE' PARAMS returns two values: the near and far mapping limits for the depth buffer. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 1). See `glDepthRange'. `GL_DEPTH_SCALE' PARAMS returns one value, the depth scale factor used during pixel transfers. The initial value is 1. See `glPixelTransfer'. `GL_DEPTH_TEST' PARAMS returns a single boolean value indicating whether depth testing of fragments is enabled. The initial value is `GL_FALSE'. See `glDepthFunc' and `glDepthRange'. `GL_DEPTH_WRITEMASK' PARAMS returns a single boolean value indicating if the depth buffer is enabled for writing. The initial value is `GL_TRUE'. See `glDepthMask'. `GL_DITHER' PARAMS returns a single boolean value indicating whether dithering of fragment colors and indices is enabled. The initial value is `GL_TRUE'. `GL_DOUBLEBUFFER' PARAMS returns a single boolean value indicating whether double buffering is supported. `GL_DRAW_BUFFER' PARAMS returns one value, a symbolic constant indicating which buffers are being drawn to. See `glDrawBuffer'. The initial value is `GL_BACK' if there are back buffers, otherwise it is `GL_FRONT'. `GL_DRAW_BUFFER'I PARAMS returns one value, a symbolic constant indicating which buffers are being drawn to by the corresponding output color. See `glDrawBuffers'. The initial value of `GL_DRAW_BUFFER0' is `GL_BACK' if there are back buffers, otherwise it is `GL_FRONT'. The initial values of draw buffers for all other output colors is `GL_NONE'. `GL_EDGE_FLAG' PARAMS returns a single boolean value indicating whether the current edge flag is `GL_TRUE' or `GL_FALSE'. The initial value is `GL_TRUE'. See `glEdgeFlag'. `GL_EDGE_FLAG_ARRAY' PARAMS returns a single boolean value indicating whether the edge flag array is enabled. The initial value is `GL_FALSE'. See `glEdgeFlagPointer'. `GL_EDGE_FLAG_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the edge flag array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glEdgeFlagPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_EDGE_FLAG_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive edge flags in the edge flag array. The initial value is 0. See `glEdgeFlagPointer'. `GL_ELEMENT_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object currently bound to the target `GL_ELEMENT_ARRAY_BUFFER'. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_FEEDBACK_BUFFER_SIZE' PARAMS returns one value, the size of the feedback buffer. See `glFeedbackBuffer'. `GL_FEEDBACK_BUFFER_TYPE' PARAMS returns one value, the type of the feedback buffer. See `glFeedbackBuffer'. `GL_FOG' PARAMS returns a single boolean value indicating whether fogging is enabled. The initial value is `GL_FALSE'. See `glFog'. `GL_FOG_COORD_ARRAY' PARAMS returns a single boolean value indicating whether the fog coordinate array is enabled. The initial value is `GL_FALSE'. See `glFogCoordPointer'. `GL_FOG_COORD_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the fog coordinate array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glFogCoordPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_FOG_COORD_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive fog coordinates in the fog coordinate array. The initial value is 0. See `glFogCoordPointer'. `GL_FOG_COORD_ARRAY_TYPE' PARAMS returns one value, the type of the fog coordinate array. The initial value is `GL_FLOAT'. See `glFogCoordPointer'. `GL_FOG_COORD_SRC' PARAMS returns one value, a symbolic constant indicating the source of the fog coordinate. The initial value is `GL_FRAGMENT_DEPTH'. See `glFog'. `GL_FOG_COLOR' PARAMS returns four values: the red, green, blue, and alpha components of the fog color. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0, 0, 0, 0). See `glFog'. `GL_FOG_DENSITY' PARAMS returns one value, the fog density parameter. The initial value is 1. See `glFog'. `GL_FOG_END' PARAMS returns one value, the end factor for the linear fog equation. The initial value is 1. See `glFog'. `GL_FOG_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the fog hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_FOG_INDEX' PARAMS returns one value, the fog color index. The initial value is 0. See `glFog'. `GL_FOG_MODE' PARAMS returns one value, a symbolic constant indicating which fog equation is selected. The initial value is `GL_EXP'. See `glFog'. `GL_FOG_START' PARAMS returns one value, the start factor for the linear fog equation. The initial value is 0. See `glFog'. `GL_FRAGMENT_SHADER_DERIVATIVE_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the derivative accuracy hint for fragment shaders. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_FRONT_FACE' PARAMS returns one value, a symbolic constant indicating whether clockwise or counterclockwise polygon winding is treated as front-facing. The initial value is `GL_CCW'. See `glFrontFace'. `GL_GENERATE_MIPMAP_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the mipmap generation filtering hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_GREEN_BIAS' PARAMS returns one value, the green bias factor used during pixel transfers. The initial value is 0. `GL_GREEN_BITS' PARAMS returns one value, the number of green bitplanes in each color buffer. `GL_GREEN_SCALE' PARAMS returns one value, the green scale factor used during pixel transfers. The initial value is 1. See `glPixelTransfer'. `GL_HISTOGRAM' PARAMS returns a single boolean value indicating whether histogram is enabled. The initial value is `GL_FALSE'. See `glHistogram'. `GL_INDEX_ARRAY' PARAMS returns a single boolean value indicating whether the color index array is enabled. The initial value is `GL_FALSE'. See `glIndexPointer'. `GL_INDEX_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the color index array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glIndexPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_INDEX_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive color indexes in the color index array. The initial value is 0. See `glIndexPointer'. `GL_INDEX_ARRAY_TYPE' PARAMS returns one value, the data type of indexes in the color index array. The initial value is `GL_FLOAT'. See `glIndexPointer'. `GL_INDEX_BITS' PARAMS returns one value, the number of bitplanes in each color index buffer. `GL_INDEX_CLEAR_VALUE' PARAMS returns one value, the color index used to clear the color index buffers. The initial value is 0. See `glClearIndex'. `GL_INDEX_LOGIC_OP' PARAMS returns a single boolean value indicating whether a fragment's index values are merged into the framebuffer using a logical operation. The initial value is `GL_FALSE'. See `glLogicOp'. `GL_INDEX_MODE' PARAMS returns a single boolean value indicating whether the GL is in color index mode (`GL_TRUE') or RGBA mode (`GL_FALSE'). `GL_INDEX_OFFSET' PARAMS returns one value, the offset added to color and stencil indices during pixel transfers. The initial value is 0. See `glPixelTransfer'. `GL_INDEX_SHIFT' PARAMS returns one value, the amount that color and stencil indices are shifted during pixel transfers. The initial value is 0. See `glPixelTransfer'. `GL_INDEX_WRITEMASK' PARAMS returns one value, a mask indicating which bitplanes of each color index buffer can be written. The initial value is all 1's. See `glIndexMask'. `GL_LIGHT'I PARAMS returns a single boolean value indicating whether the specified light is enabled. The initial value is `GL_FALSE'. See `glLight' and `glLightModel'. `GL_LIGHTING' PARAMS returns a single boolean value indicating whether lighting is enabled. The initial value is `GL_FALSE'. See `glLightModel'. `GL_LIGHT_MODEL_AMBIENT' PARAMS returns four values: the red, green, blue, and alpha components of the ambient intensity of the entire scene. Integer values, if requested, are linearly mapped from the internal floating-point representation such that 1.0 returns the most positive representable integer value, and -1.0 returns the most negative representable integer value. The initial value is (0.2, 0.2, 0.2, 1.0). See `glLightModel'. `GL_LIGHT_MODEL_COLOR_CONTROL' PARAMS returns single enumerated value indicating whether specular reflection calculations are separated from normal lighting computations. The initial value is `GL_SINGLE_COLOR'. `GL_LIGHT_MODEL_LOCAL_VIEWER' PARAMS returns a single boolean value indicating whether specular reflection calculations treat the viewer as being local to the scene. The initial value is `GL_FALSE'. See `glLightModel'. `GL_LIGHT_MODEL_TWO_SIDE' PARAMS returns a single boolean value indicating whether separate materials are used to compute lighting for front- and back-facing polygons. The initial value is `GL_FALSE'. See `glLightModel'. `GL_LINE_SMOOTH' PARAMS returns a single boolean value indicating whether antialiasing of lines is enabled. The initial value is `GL_FALSE'. See `glLineWidth'. `GL_LINE_SMOOTH_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the line antialiasing hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_LINE_STIPPLE' PARAMS returns a single boolean value indicating whether stippling of lines is enabled. The initial value is `GL_FALSE'. See `glLineStipple'. `GL_LINE_STIPPLE_PATTERN' PARAMS returns one value, the 16-bit line stipple pattern. The initial value is all 1's. See `glLineStipple'. `GL_LINE_STIPPLE_REPEAT' PARAMS returns one value, the line stipple repeat factor. The initial value is 1. See `glLineStipple'. `GL_LINE_WIDTH' PARAMS returns one value, the line width as specified with `glLineWidth'. The initial value is 1. `GL_LINE_WIDTH_GRANULARITY' PARAMS returns one value, the width difference between adjacent supported widths for antialiased lines. See `glLineWidth'. `GL_LINE_WIDTH_RANGE' PARAMS returns two values: the smallest and largest supported widths for antialiased lines. See `glLineWidth'. `GL_LIST_BASE' PARAMS returns one value, the base offset added to all names in arrays presented to `glCallLists'. The initial value is 0. See `glListBase'. `GL_LIST_INDEX' PARAMS returns one value, the name of the display list currently under construction. 0 is returned if no display list is currently under construction. The initial value is 0. See `glNewList'. `GL_LIST_MODE' PARAMS returns one value, a symbolic constant indicating the construction mode of the display list currently under construction. The initial value is 0. See `glNewList'. `GL_LOGIC_OP_MODE' PARAMS returns one value, a symbolic constant indicating the selected logic operation mode. The initial value is `GL_COPY'. See `glLogicOp'. `GL_MAP1_COLOR_4' PARAMS returns a single boolean value indicating whether 1D evaluation generates colors. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_GRID_DOMAIN' PARAMS returns two values: the endpoints of the 1D map's grid domain. The initial value is (0, 1). See `glMapGrid'. `GL_MAP1_GRID_SEGMENTS' PARAMS returns one value, the number of partitions in the 1D map's grid domain. The initial value is 1. See `glMapGrid'. `GL_MAP1_INDEX' PARAMS returns a single boolean value indicating whether 1D evaluation generates color indices. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_NORMAL' PARAMS returns a single boolean value indicating whether 1D evaluation generates normals. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_TEXTURE_COORD_1' PARAMS returns a single boolean value indicating whether 1D evaluation generates 1D texture coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_TEXTURE_COORD_2' PARAMS returns a single boolean value indicating whether 1D evaluation generates 2D texture coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_TEXTURE_COORD_3' PARAMS returns a single boolean value indicating whether 1D evaluation generates 3D texture coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_TEXTURE_COORD_4' PARAMS returns a single boolean value indicating whether 1D evaluation generates 4D texture coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_VERTEX_3' PARAMS returns a single boolean value indicating whether 1D evaluation generates 3D vertex coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP1_VERTEX_4' PARAMS returns a single boolean value indicating whether 1D evaluation generates 4D vertex coordinates. The initial value is `GL_FALSE'. See `glMap1'. `GL_MAP2_COLOR_4' PARAMS returns a single boolean value indicating whether 2D evaluation generates colors. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_GRID_DOMAIN' PARAMS returns four values: the endpoints of the 2D map's I and J grid domains. The initial value is (0,1; 0,1). See `glMapGrid'. `GL_MAP2_GRID_SEGMENTS' PARAMS returns two values: the number of partitions in the 2D map's I and J grid domains. The initial value is (1,1). See `glMapGrid'. `GL_MAP2_INDEX' PARAMS returns a single boolean value indicating whether 2D evaluation generates color indices. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_NORMAL' PARAMS returns a single boolean value indicating whether 2D evaluation generates normals. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_TEXTURE_COORD_1' PARAMS returns a single boolean value indicating whether 2D evaluation generates 1D texture coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_TEXTURE_COORD_2' PARAMS returns a single boolean value indicating whether 2D evaluation generates 2D texture coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_TEXTURE_COORD_3' PARAMS returns a single boolean value indicating whether 2D evaluation generates 3D texture coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_TEXTURE_COORD_4' PARAMS returns a single boolean value indicating whether 2D evaluation generates 4D texture coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_VERTEX_3' PARAMS returns a single boolean value indicating whether 2D evaluation generates 3D vertex coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP2_VERTEX_4' PARAMS returns a single boolean value indicating whether 2D evaluation generates 4D vertex coordinates. The initial value is `GL_FALSE'. See `glMap2'. `GL_MAP_COLOR' PARAMS returns a single boolean value indicating if colors and color indices are to be replaced by table lookup during pixel transfers. The initial value is `GL_FALSE'. See `glPixelTransfer'. `GL_MAP_STENCIL' PARAMS returns a single boolean value indicating if stencil indices are to be replaced by table lookup during pixel transfers. The initial value is `GL_FALSE'. See `glPixelTransfer'. `GL_MATRIX_MODE' PARAMS returns one value, a symbolic constant indicating which matrix stack is currently the target of all matrix operations. The initial value is `GL_MODELVIEW'. See `glMatrixMode'. `GL_MAX_3D_TEXTURE_SIZE' PARAMS returns one value, a rough estimate of the largest 3D texture that the GL can handle. The value must be at least 16. If the GL version is 1.2 or greater, use `GL_PROXY_TEXTURE_3D' to determine if a texture is too large. See `glTexImage3D'. `GL_MAX_CLIENT_ATTRIB_STACK_DEPTH' PARAMS returns one value indicating the maximum supported depth of the client attribute stack. See `glPushClientAttrib'. `GL_MAX_ATTRIB_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the attribute stack. The value must be at least 16. See `glPushAttrib'. `GL_MAX_CLIP_PLANES' PARAMS returns one value, the maximum number of application-defined clipping planes. The value must be at least 6. See `glClipPlane'. `GL_MAX_COLOR_MATRIX_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the color matrix stack. The value must be at least 2. See `glPushMatrix'. `GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS' PARAMS returns one value, the maximum supported texture image units that can be used to access texture maps from the vertex shader and the fragment processor combined. If both the vertex shader and the fragment processing stage access the same texture image unit, then that counts as using two texture image units against this limit. The value must be at least 2. See `glActiveTexture'. `GL_MAX_CUBE_MAP_TEXTURE_SIZE' PARAMS returns one value. The value gives a rough estimate of the largest cube-map texture that the GL can handle. The value must be at least 16. If the GL version is 1.3 or greater, use `GL_PROXY_TEXTURE_CUBE_MAP' to determine if a texture is too large. See `glTexImage2D'. `GL_MAX_DRAW_BUFFERS' PARAMS returns one value, the maximum number of simultaneous output colors allowed from a fragment shader using the `gl_FragData' built-in array. The value must be at least 1. See `glDrawBuffers'. `GL_MAX_ELEMENTS_INDICES' PARAMS returns one value, the recommended maximum number of vertex array indices. See `glDrawRangeElements'. `GL_MAX_ELEMENTS_VERTICES' PARAMS returns one value, the recommended maximum number of vertex array vertices. See `glDrawRangeElements'. `GL_MAX_EVAL_ORDER' PARAMS returns one value, the maximum equation order supported by 1D and 2D evaluators. The value must be at least 8. See `glMap1' and `glMap2'. `GL_MAX_FRAGMENT_UNIFORM_COMPONENTS' PARAMS returns one value, the maximum number of individual floating-point, integer, or boolean values that can be held in uniform variable storage for a fragment shader. The value must be at least 64. See `glUniform'. `GL_MAX_LIGHTS' PARAMS returns one value, the maximum number of lights. The value must be at least 8. See `glLight'. `GL_MAX_LIST_NESTING' PARAMS returns one value, the maximum recursion depth allowed during display-list traversal. The value must be at least 64. See `glCallList'. `GL_MAX_MODELVIEW_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the modelview matrix stack. The value must be at least 32. See `glPushMatrix'. `GL_MAX_NAME_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the selection name stack. The value must be at least 64. See `glPushName'. `GL_MAX_PIXEL_MAP_TABLE' PARAMS returns one value, the maximum supported size of a `glPixelMap' lookup table. The value must be at least 32. See `glPixelMap'. `GL_MAX_PROJECTION_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the projection matrix stack. The value must be at least 2. See `glPushMatrix'. `GL_MAX_TEXTURE_COORDS' PARAMS returns one value, the maximum number of texture coordinate sets available to vertex and fragment shaders. The value must be at least 2. See `glActiveTexture' and `glClientActiveTexture'. `GL_MAX_TEXTURE_IMAGE_UNITS' PARAMS returns one value, the maximum supported texture image units that can be used to access texture maps from the fragment shader. The value must be at least 2. See `glActiveTexture'. `GL_MAX_TEXTURE_LOD_BIAS' PARAMS returns one value, the maximum, absolute value of the texture level-of-detail bias. The value must be at least 4. `GL_MAX_TEXTURE_SIZE' PARAMS returns one value. The value gives a rough estimate of the largest texture that the GL can handle. The value must be at least 64. If the GL version is 1.1 or greater, use `GL_PROXY_TEXTURE_1D' or `GL_PROXY_TEXTURE_2D' to determine if a texture is too large. See `glTexImage1D' and `glTexImage2D'. `GL_MAX_TEXTURE_STACK_DEPTH' PARAMS returns one value, the maximum supported depth of the texture matrix stack. The value must be at least 2. See `glPushMatrix'. `GL_MAX_TEXTURE_UNITS' PARAMS returns a single value indicating the number of conventional texture units supported. Each conventional texture unit includes both a texture coordinate set and a texture image unit. Conventional texture units may be used for fixed-function (non-shader) rendering. The value must be at least 2. Additional texture coordinate sets and texture image units may be accessed from vertex and fragment shaders. See `glActiveTexture' and `glClientActiveTexture'. `GL_MAX_VARYING_FLOATS' PARAMS returns one value, the maximum number of interpolators available for processing varying variables used by vertex and fragment shaders. This value represents the number of individual floating-point values that can be interpolated; varying variables declared as vectors, matrices, and arrays will all consume multiple interpolators. The value must be at least 32. `GL_MAX_VERTEX_ATTRIBS' PARAMS returns one value, the maximum number of 4-component generic vertex attributes accessible to a vertex shader. The value must be at least 16. See `glVertexAttrib'. `GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS' PARAMS returns one value, the maximum supported texture image units that can be used to access texture maps from the vertex shader. The value may be 0. See `glActiveTexture'. `GL_MAX_VERTEX_UNIFORM_COMPONENTS' PARAMS returns one value, the maximum number of individual floating-point, integer, or boolean values that can be held in uniform variable storage for a vertex shader. The value must be at least 512. See `glUniform'. `GL_MAX_VIEWPORT_DIMS' PARAMS returns two values: the maximum supported width and height of the viewport. These must be at least as large as the visible dimensions of the display being rendered to. See `glViewport'. `GL_MINMAX' PARAMS returns a single boolean value indicating whether pixel minmax values are computed. The initial value is `GL_FALSE'. See `glMinmax'. `GL_MODELVIEW_MATRIX' PARAMS returns sixteen values: the modelview matrix on the top of the modelview matrix stack. Initially this matrix is the identity matrix. See `glPushMatrix'. `GL_MODELVIEW_STACK_DEPTH' PARAMS returns one value, the number of matrices on the modelview matrix stack. The initial value is 1. See `glPushMatrix'. `GL_NAME_STACK_DEPTH' PARAMS returns one value, the number of names on the selection name stack. The initial value is 0. See `glPushName'. `GL_NORMAL_ARRAY' PARAMS returns a single boolean value, indicating whether the normal array is enabled. The initial value is `GL_FALSE'. See `glNormalPointer'. `GL_NORMAL_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the normal array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glNormalPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_NORMAL_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive normals in the normal array. The initial value is 0. See `glNormalPointer'. `GL_NORMAL_ARRAY_TYPE' PARAMS returns one value, the data type of each coordinate in the normal array. The initial value is `GL_FLOAT'. See `glNormalPointer'. `GL_NORMALIZE' PARAMS returns a single boolean value indicating whether normals are automatically scaled to unit length after they have been transformed to eye coordinates. The initial value is `GL_FALSE'. See `glNormal'. `GL_NUM_COMPRESSED_TEXTURE_FORMATS' PARAMS returns a single integer value indicating the number of available compressed texture formats. The minimum value is 0. See `glCompressedTexImage2D'. `GL_PACK_ALIGNMENT' PARAMS returns one value, the byte alignment used for writing pixel data to memory. The initial value is 4. See `glPixelStore'. `GL_PACK_IMAGE_HEIGHT' PARAMS returns one value, the image height used for writing pixel data to memory. The initial value is 0. See `glPixelStore'. `GL_PACK_LSB_FIRST' PARAMS returns a single boolean value indicating whether single-bit pixels being written to memory are written first to the least significant bit of each unsigned byte. The initial value is `GL_FALSE'. See `glPixelStore'. `GL_PACK_ROW_LENGTH' PARAMS returns one value, the row length used for writing pixel data to memory. The initial value is 0. See `glPixelStore'. `GL_PACK_SKIP_IMAGES' PARAMS returns one value, the number of pixel images skipped before the first pixel is written into memory. The initial value is 0. See `glPixelStore'. `GL_PACK_SKIP_PIXELS' PARAMS returns one value, the number of pixel locations skipped before the first pixel is written into memory. The initial value is 0. See `glPixelStore'. `GL_PACK_SKIP_ROWS' PARAMS returns one value, the number of rows of pixel locations skipped before the first pixel is written into memory. The initial value is 0. See `glPixelStore'. `GL_PACK_SWAP_BYTES' PARAMS returns a single boolean value indicating whether the bytes of two-byte and four-byte pixel indices and components are swapped before being written to memory. The initial value is `GL_FALSE'. See `glPixelStore'. `GL_PERSPECTIVE_CORRECTION_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the perspective correction hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_PIXEL_MAP_A_TO_A_SIZE' PARAMS returns one value, the size of the alpha-to-alpha pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_B_TO_B_SIZE' PARAMS returns one value, the size of the blue-to-blue pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_G_TO_G_SIZE' PARAMS returns one value, the size of the green-to-green pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_I_TO_A_SIZE' PARAMS returns one value, the size of the index-to-alpha pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_I_TO_B_SIZE' PARAMS returns one value, the size of the index-to-blue pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_I_TO_G_SIZE' PARAMS returns one value, the size of the index-to-green pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_I_TO_I_SIZE' PARAMS returns one value, the size of the index-to-index pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_I_TO_R_SIZE' PARAMS returns one value, the size of the index-to-red pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_R_TO_R_SIZE' PARAMS returns one value, the size of the red-to-red pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_MAP_S_TO_S_SIZE' PARAMS returns one value, the size of the stencil-to-stencil pixel translation table. The initial value is 1. See `glPixelMap'. `GL_PIXEL_PACK_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object currently bound to the target `GL_PIXEL_PACK_BUFFER'. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_PIXEL_UNPACK_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object currently bound to the target `GL_PIXEL_UNPACK_BUFFER'. If no buffer object is bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_POINT_DISTANCE_ATTENUATION' PARAMS returns three values, the coefficients for computing the attenuation value for points. See `glPointParameter'. `GL_POINT_FADE_THRESHOLD_SIZE' PARAMS returns one value, the point size threshold for determining the point size. See `glPointParameter'. `GL_POINT_SIZE' PARAMS returns one value, the point size as specified by `glPointSize'. The initial value is 1. `GL_POINT_SIZE_GRANULARITY' PARAMS returns one value, the size difference between adjacent supported sizes for antialiased points. See `glPointSize'. `GL_POINT_SIZE_MAX' PARAMS returns one value, the upper bound for the attenuated point sizes. The initial value is 0.0. See `glPointParameter'. `GL_POINT_SIZE_MIN' PARAMS returns one value, the lower bound for the attenuated point sizes. The initial value is 1.0. See `glPointParameter'. `GL_POINT_SIZE_RANGE' PARAMS returns two values: the smallest and largest supported sizes for antialiased points. The smallest size must be at most 1, and the largest size must be at least 1. See `glPointSize'. `GL_POINT_SMOOTH' PARAMS returns a single boolean value indicating whether antialiasing of points is enabled. The initial value is `GL_FALSE'. See `glPointSize'. `GL_POINT_SMOOTH_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the point antialiasing hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_POINT_SPRITE' PARAMS returns a single boolean value indicating whether point sprite is enabled. The initial value is `GL_FALSE'. `GL_POLYGON_MODE' PARAMS returns two values: symbolic constants indicating whether front-facing and back-facing polygons are rasterized as points, lines, or filled polygons. The initial value is `GL_FILL'. See `glPolygonMode'. `GL_POLYGON_OFFSET_FACTOR' PARAMS returns one value, the scaling factor used to determine the variable offset that is added to the depth value of each fragment generated when a polygon is rasterized. The initial value is 0. See `glPolygonOffset'. `GL_POLYGON_OFFSET_UNITS' PARAMS returns one value. This value is multiplied by an implementation-specific value and then added to the depth value of each fragment generated when a polygon is rasterized. The initial value is 0. See `glPolygonOffset'. `GL_POLYGON_OFFSET_FILL' PARAMS returns a single boolean value indicating whether polygon offset is enabled for polygons in fill mode. The initial value is `GL_FALSE'. See `glPolygonOffset'. `GL_POLYGON_OFFSET_LINE' PARAMS returns a single boolean value indicating whether polygon offset is enabled for polygons in line mode. The initial value is `GL_FALSE'. See `glPolygonOffset'. `GL_POLYGON_OFFSET_POINT' PARAMS returns a single boolean value indicating whether polygon offset is enabled for polygons in point mode. The initial value is `GL_FALSE'. See `glPolygonOffset'. `GL_POLYGON_SMOOTH' PARAMS returns a single boolean value indicating whether antialiasing of polygons is enabled. The initial value is `GL_FALSE'. See `glPolygonMode'. `GL_POLYGON_SMOOTH_HINT' PARAMS returns one value, a symbolic constant indicating the mode of the polygon antialiasing hint. The initial value is `GL_DONT_CARE'. See `glHint'. `GL_POLYGON_STIPPLE' PARAMS returns a single boolean value indicating whether polygon stippling is enabled. The initial value is `GL_FALSE'. See `glPolygonStipple'. `GL_POST_COLOR_MATRIX_COLOR_TABLE' PARAMS returns a single boolean value indicating whether post color matrix transformation lookup is enabled. The initial value is `GL_FALSE'. See `glColorTable'. `GL_POST_COLOR_MATRIX_RED_BIAS' PARAMS returns one value, the red bias factor applied to RGBA fragments after color matrix transformations. The initial value is 0. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_GREEN_BIAS' PARAMS returns one value, the green bias factor applied to RGBA fragments after color matrix transformations. The initial value is 0. See `glPixelTransfer' `GL_POST_COLOR_MATRIX_BLUE_BIAS' PARAMS returns one value, the blue bias factor applied to RGBA fragments after color matrix transformations. The initial value is 0. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_ALPHA_BIAS' PARAMS returns one value, the alpha bias factor applied to RGBA fragments after color matrix transformations. The initial value is 0. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_RED_SCALE' PARAMS returns one value, the red scale factor applied to RGBA fragments after color matrix transformations. The initial value is 1. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_GREEN_SCALE' PARAMS returns one value, the green scale factor applied to RGBA fragments after color matrix transformations. The initial value is 1. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_BLUE_SCALE' PARAMS returns one value, the blue scale factor applied to RGBA fragments after color matrix transformations. The initial value is 1. See `glPixelTransfer'. `GL_POST_COLOR_MATRIX_ALPHA_SCALE' PARAMS returns one value, the alpha scale factor applied to RGBA fragments after color matrix transformations. The initial value is 1. See `glPixelTransfer'. `GL_POST_CONVOLUTION_COLOR_TABLE' PARAMS returns a single boolean value indicating whether post convolution lookup is enabled. The initial value is `GL_FALSE'. See `glColorTable'. `GL_POST_CONVOLUTION_RED_BIAS' PARAMS returns one value, the red bias factor applied to RGBA fragments after convolution. The initial value is 0. See `glPixelTransfer'. `GL_POST_CONVOLUTION_GREEN_BIAS' PARAMS returns one value, the green bias factor applied to RGBA fragments after convolution. The initial value is 0. See `glPixelTransfer'. `GL_POST_CONVOLUTION_BLUE_BIAS' PARAMS returns one value, the blue bias factor applied to RGBA fragments after convolution. The initial value is 0. See `glPixelTransfer'. `GL_POST_CONVOLUTION_ALPHA_BIAS' PARAMS returns one value, the alpha bias factor applied to RGBA fragments after convolution. The initial value is 0. See `glPixelTransfer'. `GL_POST_CONVOLUTION_RED_SCALE' PARAMS returns one value, the red scale factor applied to RGBA fragments after convolution. The initial value is 1. See `glPixelTransfer'. `GL_POST_CONVOLUTION_GREEN_SCALE' PARAMS returns one value, the green scale factor applied to RGBA fragments after convolution. The initial value is 1. See `glPixelTransfer'. `GL_POST_CONVOLUTION_BLUE_SCALE' PARAMS returns one value, the blue scale factor applied to RGBA fragments after convolution. The initial value is 1. See `glPixelTransfer'. `GL_POST_CONVOLUTION_ALPHA_SCALE' PARAMS returns one value, the alpha scale factor applied to RGBA fragments after convolution. The initial value is 1. See `glPixelTransfer'. `GL_PROJECTION_MATRIX' PARAMS returns sixteen values: the projection matrix on the top of the projection matrix stack. Initially this matrix is the identity matrix. See `glPushMatrix'. `GL_PROJECTION_STACK_DEPTH' PARAMS returns one value, the number of matrices on the projection matrix stack. The initial value is 1. See `glPushMatrix'. `GL_READ_BUFFER' PARAMS returns one value, a symbolic constant indicating which color buffer is selected for reading. The initial value is `GL_BACK' if there is a back buffer, otherwise it is `GL_FRONT'. See `glReadPixels' and `glAccum'. `GL_RED_BIAS' PARAMS returns one value, the red bias factor used during pixel transfers. The initial value is 0. `GL_RED_BITS' PARAMS returns one value, the number of red bitplanes in each color buffer. `GL_RED_SCALE' PARAMS returns one value, the red scale factor used during pixel transfers. The initial value is 1. See `glPixelTransfer'. `GL_RENDER_MODE' PARAMS returns one value, a symbolic constant indicating whether the GL is in render, select, or feedback mode. The initial value is `GL_RENDER'. See `glRenderMode'. `GL_RESCALE_NORMAL' PARAMS returns single boolean value indicating whether normal rescaling is enabled. See `glEnable'. `GL_RGBA_MODE' PARAMS returns a single boolean value indicating whether the GL is in RGBA mode (true) or color index mode (false). See `glColor'. `GL_SAMPLE_BUFFERS' PARAMS returns a single integer value indicating the number of sample buffers associated with the framebuffer. See `glSampleCoverage'. `GL_SAMPLE_COVERAGE_VALUE' PARAMS returns a single positive floating-point value indicating the current sample coverage value. See `glSampleCoverage'. `GL_SAMPLE_COVERAGE_INVERT' PARAMS returns a single boolean value indicating if the temporary coverage value should be inverted. See `glSampleCoverage'. `GL_SAMPLES' PARAMS returns a single integer value indicating the coverage mask size. See `glSampleCoverage'. `GL_SCISSOR_BOX' PARAMS returns four values: the X and Y window coordinates of the scissor box, followed by its width and height. Initially the X and Y window coordinates are both 0 and the width and height are set to the size of the window. See `glScissor'. `GL_SCISSOR_TEST' PARAMS returns a single boolean value indicating whether scissoring is enabled. The initial value is `GL_FALSE'. See `glScissor'. `GL_SECONDARY_COLOR_ARRAY' PARAMS returns a single boolean value indicating whether the secondary color array is enabled. The initial value is `GL_FALSE'. See `glSecondaryColorPointer'. `GL_SECONDARY_COLOR_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the secondary color array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glSecondaryColorPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_SECONDARY_COLOR_ARRAY_SIZE' PARAMS returns one value, the number of components per color in the secondary color array. The initial value is 3. See `glSecondaryColorPointer'. `GL_SECONDARY_COLOR_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive colors in the secondary color array. The initial value is 0. See `glSecondaryColorPointer'. `GL_SECONDARY_COLOR_ARRAY_TYPE' PARAMS returns one value, the data type of each component in the secondary color array. The initial value is `GL_FLOAT'. See `glSecondaryColorPointer'. `GL_SELECTION_BUFFER_SIZE' PARAMS return one value, the size of the selection buffer. See `glSelectBuffer'. `GL_SEPARABLE_2D' PARAMS returns a single boolean value indicating whether 2D separable convolution is enabled. The initial value is `GL_FALSE'. See `glSeparableFilter2D'. `GL_SHADE_MODEL' PARAMS returns one value, a symbolic constant indicating whether the shading mode is flat or smooth. The initial value is `GL_SMOOTH'. See `glShadeModel'. `GL_SMOOTH_LINE_WIDTH_RANGE' PARAMS returns two values, the smallest and largest supported widths for antialiased lines. See `glLineWidth'. `GL_SMOOTH_LINE_WIDTH_GRANULARITY' PARAMS returns one value, the granularity of widths for antialiased lines. See `glLineWidth'. `GL_SMOOTH_POINT_SIZE_RANGE' PARAMS returns two values, the smallest and largest supported widths for antialiased points. See `glPointSize'. `GL_SMOOTH_POINT_SIZE_GRANULARITY' PARAMS returns one value, the granularity of sizes for antialiased points. See `glPointSize'. `GL_STENCIL_BACK_FAIL' PARAMS returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test fails. The initial value is `GL_KEEP'. See `glStencilOpSeparate'. `GL_STENCIL_BACK_FUNC' PARAMS returns one value, a symbolic constant indicating what function is used for back-facing polygons to compare the stencil reference value with the stencil buffer value. The initial value is `GL_ALWAYS'. See `glStencilFuncSeparate'. `GL_STENCIL_BACK_PASS_DEPTH_FAIL' PARAMS returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test passes, but the depth test fails. The initial value is `GL_KEEP'. See `glStencilOpSeparate'. `GL_STENCIL_BACK_PASS_DEPTH_PASS' PARAMS returns one value, a symbolic constant indicating what action is taken for back-facing polygons when the stencil test passes and the depth test passes. The initial value is `GL_KEEP'. See `glStencilOpSeparate'. `GL_STENCIL_BACK_REF' PARAMS returns one value, the reference value that is compared with the contents of the stencil buffer for back-facing polygons. The initial value is 0. See `glStencilFuncSeparate'. `GL_STENCIL_BACK_VALUE_MASK' PARAMS returns one value, the mask that is used for back-facing polygons to mask both the stencil reference value and the stencil buffer value before they are compared. The initial value is all 1's. See `glStencilFuncSeparate'. `GL_STENCIL_BACK_WRITEMASK' PARAMS returns one value, the mask that controls writing of the stencil bitplanes for back-facing polygons. The initial value is all 1's. See `glStencilMaskSeparate'. `GL_STENCIL_BITS' PARAMS returns one value, the number of bitplanes in the stencil buffer. `GL_STENCIL_CLEAR_VALUE' PARAMS returns one value, the index to which the stencil bitplanes are cleared. The initial value is 0. See `glClearStencil'. `GL_STENCIL_FAIL' PARAMS returns one value, a symbolic constant indicating what action is taken when the stencil test fails. The initial value is `GL_KEEP'. See `glStencilOp'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilOpSeparate'. `GL_STENCIL_FUNC' PARAMS returns one value, a symbolic constant indicating what function is used to compare the stencil reference value with the stencil buffer value. The initial value is `GL_ALWAYS'. See `glStencilFunc'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilFuncSeparate'. `GL_STENCIL_PASS_DEPTH_FAIL' PARAMS returns one value, a symbolic constant indicating what action is taken when the stencil test passes, but the depth test fails. The initial value is `GL_KEEP'. See `glStencilOp'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilOpSeparate'. `GL_STENCIL_PASS_DEPTH_PASS' PARAMS returns one value, a symbolic constant indicating what action is taken when the stencil test passes and the depth test passes. The initial value is `GL_KEEP'. See `glStencilOp'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilOpSeparate'. `GL_STENCIL_REF' PARAMS returns one value, the reference value that is compared with the contents of the stencil buffer. The initial value is 0. See `glStencilFunc'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilFuncSeparate'. `GL_STENCIL_TEST' PARAMS returns a single boolean value indicating whether stencil testing of fragments is enabled. The initial value is `GL_FALSE'. See `glStencilFunc' and `glStencilOp'. `GL_STENCIL_VALUE_MASK' PARAMS returns one value, the mask that is used to mask both the stencil reference value and the stencil buffer value before they are compared. The initial value is all 1's. See `glStencilFunc'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilFuncSeparate'. `GL_STENCIL_WRITEMASK' PARAMS returns one value, the mask that controls writing of the stencil bitplanes. The initial value is all 1's. See `glStencilMask'. If the GL version is 2.0 or greater, this stencil state only affects non-polygons and front-facing polygons. Back-facing polygons use separate stencil state. See `glStencilMaskSeparate'. `GL_STEREO' PARAMS returns a single boolean value indicating whether stereo buffers (left and right) are supported. `GL_SUBPIXEL_BITS' PARAMS returns one value, an estimate of the number of bits of subpixel resolution that are used to position rasterized geometry in window coordinates. The value must be at least 4. `GL_TEXTURE_1D' PARAMS returns a single boolean value indicating whether 1D texture mapping is enabled. The initial value is `GL_FALSE'. See `glTexImage1D'. `GL_TEXTURE_BINDING_1D' PARAMS returns a single value, the name of the texture currently bound to the target `GL_TEXTURE_1D'. The initial value is 0. See `glBindTexture'. `GL_TEXTURE_2D' PARAMS returns a single boolean value indicating whether 2D texture mapping is enabled. The initial value is `GL_FALSE'. See `glTexImage2D'. `GL_TEXTURE_BINDING_2D' PARAMS returns a single value, the name of the texture currently bound to the target `GL_TEXTURE_2D'. The initial value is 0. See `glBindTexture'. `GL_TEXTURE_3D' PARAMS returns a single boolean value indicating whether 3D texture mapping is enabled. The initial value is `GL_FALSE'. See `glTexImage3D'. `GL_TEXTURE_BINDING_3D' PARAMS returns a single value, the name of the texture currently bound to the target `GL_TEXTURE_3D'. The initial value is 0. See `glBindTexture'. `GL_TEXTURE_BINDING_CUBE_MAP' PARAMS returns a single value, the name of the texture currently bound to the target `GL_TEXTURE_CUBE_MAP'. The initial value is 0. See `glBindTexture'. `GL_TEXTURE_COMPRESSION_HINT' PARAMS returns a single value indicating the mode of the texture compression hint. The initial value is `GL_DONT_CARE'. `GL_TEXTURE_COORD_ARRAY' PARAMS returns a single boolean value indicating whether the texture coordinate array is enabled. The initial value is `GL_FALSE'. See `glTexCoordPointer'. `GL_TEXTURE_COORD_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the texture coordinate array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glTexCoordPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_TEXTURE_COORD_ARRAY_SIZE' PARAMS returns one value, the number of coordinates per element in the texture coordinate array. The initial value is 4. See `glTexCoordPointer'. `GL_TEXTURE_COORD_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive elements in the texture coordinate array. The initial value is 0. See `glTexCoordPointer'. `GL_TEXTURE_COORD_ARRAY_TYPE' PARAMS returns one value, the data type of the coordinates in the texture coordinate array. The initial value is `GL_FLOAT'. See `glTexCoordPointer'. `GL_TEXTURE_CUBE_MAP' PARAMS returns a single boolean value indicating whether cube-mapped texture mapping is enabled. The initial value is `GL_FALSE'. See `glTexImage2D'. `GL_TEXTURE_GEN_Q' PARAMS returns a single boolean value indicating whether automatic generation of the Q texture coordinate is enabled. The initial value is `GL_FALSE'. See `glTexGen'. `GL_TEXTURE_GEN_R' PARAMS returns a single boolean value indicating whether automatic generation of the R texture coordinate is enabled. The initial value is `GL_FALSE'. See `glTexGen'. `GL_TEXTURE_GEN_S' PARAMS returns a single boolean value indicating whether automatic generation of the S texture coordinate is enabled. The initial value is `GL_FALSE'. See `glTexGen'. `GL_TEXTURE_GEN_T' PARAMS returns a single boolean value indicating whether automatic generation of the T texture coordinate is enabled. The initial value is `GL_FALSE'. See `glTexGen'. `GL_TEXTURE_MATRIX' PARAMS returns sixteen values: the texture matrix on the top of the texture matrix stack. Initially this matrix is the identity matrix. See `glPushMatrix'. `GL_TEXTURE_STACK_DEPTH' PARAMS returns one value, the number of matrices on the texture matrix stack. The initial value is 1. See `glPushMatrix'. `GL_TRANSPOSE_COLOR_MATRIX' PARAMS returns 16 values, the elements of the color matrix in row-major order. See `glLoadTransposeMatrix'. `GL_TRANSPOSE_MODELVIEW_MATRIX' PARAMS returns 16 values, the elements of the modelview matrix in row-major order. See `glLoadTransposeMatrix'. `GL_TRANSPOSE_PROJECTION_MATRIX' PARAMS returns 16 values, the elements of the projection matrix in row-major order. See `glLoadTransposeMatrix'. `GL_TRANSPOSE_TEXTURE_MATRIX' PARAMS returns 16 values, the elements of the texture matrix in row-major order. See `glLoadTransposeMatrix'. `GL_UNPACK_ALIGNMENT' PARAMS returns one value, the byte alignment used for reading pixel data from memory. The initial value is 4. See `glPixelStore'. `GL_UNPACK_IMAGE_HEIGHT' PARAMS returns one value, the image height used for reading pixel data from memory. The initial is 0. See `glPixelStore'. `GL_UNPACK_LSB_FIRST' PARAMS returns a single boolean value indicating whether single-bit pixels being read from memory are read first from the least significant bit of each unsigned byte. The initial value is `GL_FALSE'. See `glPixelStore'. `GL_UNPACK_ROW_LENGTH' PARAMS returns one value, the row length used for reading pixel data from memory. The initial value is 0. See `glPixelStore'. `GL_UNPACK_SKIP_IMAGES' PARAMS returns one value, the number of pixel images skipped before the first pixel is read from memory. The initial value is 0. See `glPixelStore'. `GL_UNPACK_SKIP_PIXELS' PARAMS returns one value, the number of pixel locations skipped before the first pixel is read from memory. The initial value is 0. See `glPixelStore'. `GL_UNPACK_SKIP_ROWS' PARAMS returns one value, the number of rows of pixel locations skipped before the first pixel is read from memory. The initial value is 0. See `glPixelStore'. `GL_UNPACK_SWAP_BYTES' PARAMS returns a single boolean value indicating whether the bytes of two-byte and four-byte pixel indices and components are swapped after being read from memory. The initial value is `GL_FALSE'. See `glPixelStore'. `GL_VERTEX_ARRAY' PARAMS returns a single boolean value indicating whether the vertex array is enabled. The initial value is `GL_FALSE'. See `glVertexPointer'. `GL_VERTEX_ARRAY_BUFFER_BINDING' PARAMS returns a single value, the name of the buffer object associated with the vertex array. This buffer object would have been bound to the target `GL_ARRAY_BUFFER' at the time of the most recent call to `glVertexPointer'. If no buffer object was bound to this target, 0 is returned. The initial value is 0. See `glBindBuffer'. `GL_VERTEX_ARRAY_SIZE' PARAMS returns one value, the number of coordinates per vertex in the vertex array. The initial value is 4. See `glVertexPointer'. `GL_VERTEX_ARRAY_STRIDE' PARAMS returns one value, the byte offset between consecutive vertices in the vertex array. The initial value is 0. See `glVertexPointer'. `GL_VERTEX_ARRAY_TYPE' PARAMS returns one value, the data type of each coordinate in the vertex array. The initial value is `GL_FLOAT'. See `glVertexPointer'. `GL_VERTEX_PROGRAM_POINT_SIZE' PARAMS returns a single boolean value indicating whether vertex program point size mode is enabled. If enabled, and a vertex shader is active, then the point size is taken from the shader built-in `gl_PointSize'. If disabled, and a vertex shader is active, then the point size is taken from the point state as specified by `glPointSize'. The initial value is `GL_FALSE'. `GL_VERTEX_PROGRAM_TWO_SIDE' PARAMS returns a single boolean value indicating whether vertex program two-sided color mode is enabled. If enabled, and a vertex shader is active, then the GL chooses the back color output for back-facing polygons, and the front color output for non-polygons and front-facing polygons. If disabled, and a vertex shader is active, then the front color output is always selected. The initial value is `GL_FALSE'. `GL_VIEWPORT' PARAMS returns four values: the X and Y window coordinates of the viewport, followed by its width and height. Initially the X and Y window coordinates are both set to 0, and the width and height are set to the width and height of the window into which the GL will do its rendering. See `glViewport'. `GL_ZOOM_X' PARAMS returns one value, the X pixel zoom factor. The initial value is 1. See `glPixelZoom'. `GL_ZOOM_Y' PARAMS returns one value, the Y pixel zoom factor. The initial value is 1. See `glPixelZoom'. Many of the boolean parameters can also be queried more easily using `glIsEnabled'. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glGet' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glHint (target GLenum) (mode GLenum) -> void)) "Specify implementation-specific hints. TARGET Specifies a symbolic constant indicating the behavior to be controlled. `GL_FOG_HINT', `GL_GENERATE_MIPMAP_HINT', `GL_LINE_SMOOTH_HINT', `GL_PERSPECTIVE_CORRECTION_HINT', `GL_POINT_SMOOTH_HINT', `GL_POLYGON_SMOOTH_HINT', `GL_TEXTURE_COMPRESSION_HINT', and `GL_FRAGMENT_SHADER_DERIVATIVE_HINT' are accepted. MODE Specifies a symbolic constant indicating the desired behavior. `GL_FASTEST', `GL_NICEST', and `GL_DONT_CARE' are accepted. Certain aspects of GL behavior, when there is room for interpretation, can be controlled with hints. A hint is specified with two arguments. TARGET is a symbolic constant indicating the behavior to be controlled, and MODE is another symbolic constant indicating the desired behavior. The initial value for each TARGET is `GL_DONT_CARE'. MODE can be one of the following: `GL_FASTEST' The most efficient option should be chosen. `GL_NICEST' The most correct, or highest quality, option should be chosen. `GL_DONT_CARE' No preference. Though the implementation aspects that can be hinted are well defined, the interpretation of the hints depends on the implementation. The hint aspects that can be specified with TARGET, along with suggested semantics, are as follows: `GL_FOG_HINT' Indicates the accuracy of fog calculation. If per-pixel fog calculation is not efficiently supported by the GL implementation, hinting `GL_DONT_CARE' or `GL_FASTEST' can result in per-vertex calculation of fog effects. `GL_FRAGMENT_SHADER_DERIVATIVE_HINT' Indicates the accuracy of the derivative calculation for the GL shading language fragment processing built-in functions: `dFdx', `dFdy', and `fwidth'. `GL_GENERATE_MIPMAP_HINT' Indicates the quality of filtering when generating mipmap images. `GL_LINE_SMOOTH_HINT' Indicates the sampling quality of antialiased lines. If a larger filter function is applied, hinting `GL_NICEST' can result in more pixel fragments being generated during rasterization. `GL_PERSPECTIVE_CORRECTION_HINT' Indicates the quality of color, texture coordinate, and fog coordinate interpolation. If perspective-corrected parameter interpolation is not efficiently supported by the GL implementation, hinting `GL_DONT_CARE' or `GL_FASTEST' can result in simple linear interpolation of colors and/or texture coordinates. `GL_POINT_SMOOTH_HINT' Indicates the sampling quality of antialiased points. If a larger filter function is applied, hinting `GL_NICEST' can result in more pixel fragments being generated during rasterization. `GL_POLYGON_SMOOTH_HINT' Indicates the sampling quality of antialiased polygons. Hinting `GL_NICEST' can result in more pixel fragments being generated during rasterization, if a larger filter function is applied. `GL_TEXTURE_COMPRESSION_HINT' Indicates the quality and performance of the compressing texture images. Hinting `GL_FASTEST' indicates that texture images should be compressed as quickly as possible, while `GL_NICEST' indicates that texture images should be compressed with as little image quality loss as possible. `GL_NICEST' should be selected if the texture is to be retrieved by `glGetCompressedTexImage' for reuse. `GL_INVALID_ENUM' is generated if either TARGET or MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glHint' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glHistogram (target GLenum) (width GLsizei) (internalformat GLenum) (sink GLboolean) -> void)) "Define histogram table. TARGET The histogram whose parameters are to be set. Must be one of `GL_HISTOGRAM' or `GL_PROXY_HISTOGRAM'. WIDTH The number of entries in the histogram table. Must be a power of 2. INTERNALFORMAT The format of entries in the histogram table. Must be one of `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. SINK If `GL_TRUE', pixels will be consumed by the histogramming process and no drawing or texture loading will take place. If `GL_FALSE', pixels will proceed to the minmax process after histogramming. When `GL_HISTOGRAM' is enabled, RGBA color components are converted to histogram table indices by clamping to the range [0,1], multiplying by the width of the histogram table, and rounding to the nearest integer. The table entries selected by the RGBA indices are then incremented. (If the internal format of the histogram table includes luminance, then the index derived from the R color component determines the luminance table entry to be incremented.) If a histogram table entry is incremented beyond its maximum value, then its value becomes undefined. (This is not an error.) Histogramming is performed only for RGBA pixels (though these may be specified originally as color indices and converted to RGBA by index table lookup). Histogramming is enabled with `glEnable' and disabled with `glDisable'. When TARGET is `GL_HISTOGRAM', `glHistogram' redefines the current histogram table to have WIDTH entries of the format specified by INTERNALFORMAT. The entries are indexed 0 through WIDTH-1 , and all entries are initialized to zero. The values in the previous histogram table, if any, are lost. If SINK is `GL_TRUE', then pixels are discarded after histogramming; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result. When TARGET is `GL_PROXY_HISTOGRAM', `glHistogram' computes all state information as if the histogram table were to be redefined, but does not actually define the new table. If the requested histogram table is too large to be supported, then the state information will be set to zero. This provides a way to determine if a histogram table with the given parameters can be supported. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or is not a power of 2. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_TABLE_TOO_LARGE' is generated if TARGET is `GL_HISTOGRAM' and the histogram table specified is too large for the implementation. `GL_INVALID_OPERATION' is generated if `glHistogram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIndexMask (mask GLuint) -> void)) "Control the writing of individual bits in the color index buffers. MASK Specifies a bit mask to enable and disable the writing of individual bits in the color index buffers. Initially, the mask is all 1's. `glIndexMask' controls the writing of individual bits in the color index buffers. The least significant N bits of MASK, where N is the number of bits in a color index buffer, specify a mask. Where a 1 (one) appears in the mask, it's possible to write to the corresponding bit in the color index buffer (or buffers). Where a 0 (zero) appears, the corresponding bit is write-protected. This mask is used only in color index mode, and it affects only the buffers currently selected for writing (see `glDrawBuffer'). Initially, all bits are enabled for writing. `GL_INVALID_OPERATION' is generated if `glIndexMask' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIndexPointer (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of color indexes. TYPE Specifies the data type of each color index in the array. Symbolic constants `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_INT', `GL_FLOAT', and `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive color indexes. If STRIDE is 0, the color indexes are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first index in the array. The initial value is 0. `glIndexPointer' specifies the location and data format of an array of color indexes to use when rendering. TYPE specifies the data type of each color index and STRIDE specifies the byte stride from one color index to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a color index array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as color index vertex array client-side state (`GL_INDEX_ARRAY_BUFFER_BINDING'). When a color index array is specified, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the color index array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_INDEX_ARRAY'. If enabled, the color index array is used when `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', `glDrawRangeElements', or `glArrayElement' is called. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glIndexi (c GLint) -> void) (glIndexf (c GLfloat) -> void) (glIndexub (c GLubyte) -> void)) "Set the current color index. C Specifies the new value for the current color index. `glIndex' updates the current (single-valued) color index. It takes one argument, the new value for the current color index. The current index is stored as a floating-point value. Integer values are converted directly to floating-point values, with no special mapping. The initial value is 1. Index values outside the representable range of the color index buffer are not clamped. However, before an index is dithered (if enabled) and written to the frame buffer, it is converted to fixed-point format. Any bits in the integer portion of the resulting fixed-point value that do not correspond to bits in the frame buffer are masked out.") (define-gl-procedures ((glInitNames -> void)) "Initialize the name stack. The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers. `glInitNames' causes the name stack to be initialized to its default empty state. The name stack is always empty while the render mode is not `GL_SELECT'. Calls to `glInitNames' while the render mode is not `GL_SELECT' are ignored. `GL_INVALID_OPERATION' is generated if `glInitNames' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glInterleavedArrays (format GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Simultaneously specify and enable several interleaved arrays. FORMAT Specifies the type of array to enable. Symbolic constants `GL_V2F', `GL_V3F', `GL_C4UB_V2F', `GL_C4UB_V3F', `GL_C3F_V3F', `GL_N3F_V3F', `GL_C4F_N3F_V3F', `GL_T2F_V3F', `GL_T4F_V4F', `GL_T2F_C4UB_V3F', `GL_T2F_C3F_V3F', `GL_T2F_N3F_V3F', `GL_T2F_C4F_N3F_V3F', and `GL_T4F_C4F_N3F_V4F' are accepted. STRIDE Specifies the offset in bytes between each aggregate array element. `glInterleavedArrays' lets you specify and enable individual color, normal, texture and vertex arrays whose elements are part of a larger aggregate array element. For some implementations, this is more efficient than specifying the arrays separately. If STRIDE is 0, the aggregate elements are stored consecutively. Otherwise, STRIDE bytes occur between the beginning of one aggregate array element and the beginning of the next aggregate array element. FORMAT serves as a ``key'' describing the extraction of individual arrays from the aggregate array. If FORMAT contains a T, then texture coordinates are extracted from the interleaved array. If C is present, color values are extracted. If N is present, normal coordinates are extracted. Vertex coordinates are always extracted. The digits 2, 3, and 4 denote how many values are extracted. F indicates that values are extracted as floating-point values. Colors may also be extracted as 4 unsigned bytes if 4UB follows the C. If a color is extracted as 4 unsigned bytes, the vertex array element which follows is located at the first possible floating-point aligned address. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glIsBuffer (buffer GLuint) -> GLboolean)) "Determine if a name corresponds to a buffer object. BUFFER Specifies a value that may be the name of a buffer object. `glIsBuffer' returns `GL_TRUE' if BUFFER is currently the name of a buffer object. If BUFFER is zero, or is a non-zero value that is not currently the name of a buffer object, or if an error occurs, `glIsBuffer' returns `GL_FALSE'. A name returned by `glGenBuffers', but not yet associated with a buffer object by calling `glBindBuffer', is not the name of a buffer object. `GL_INVALID_OPERATION' is generated if `glIsBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsEnabled (cap GLenum) -> GLboolean)) "Test whether a capability is enabled. CAP Specifies a symbolic constant indicating a GL capability. `glIsEnabled' returns `GL_TRUE' if CAP is an enabled capability and returns `GL_FALSE' otherwise. Initially all capabilities except `GL_DITHER' are disabled; `GL_DITHER' is initially enabled. The following capabilities are accepted for CAP: *Constant* *See* `GL_ALPHA_TEST' `glAlphaFunc' `GL_AUTO_NORMAL' `glEvalCoord' `GL_BLEND' `glBlendFunc', `glLogicOp' `GL_CLIP_PLANE'I `glClipPlane' `GL_COLOR_ARRAY' `glColorPointer' `GL_COLOR_LOGIC_OP' `glLogicOp' `GL_COLOR_MATERIAL' `glColorMaterial' `GL_COLOR_SUM' `glSecondaryColor' `GL_COLOR_TABLE' `glColorTable' `GL_CONVOLUTION_1D' `glConvolutionFilter1D' `GL_CONVOLUTION_2D' `glConvolutionFilter2D' `GL_CULL_FACE' `glCullFace' `GL_DEPTH_TEST' `glDepthFunc', `glDepthRange' `GL_DITHER' `glEnable' `GL_EDGE_FLAG_ARRAY' `glEdgeFlagPointer' `GL_FOG' `glFog' `GL_FOG_COORD_ARRAY' `glFogCoordPointer' `GL_HISTOGRAM' `glHistogram' `GL_INDEX_ARRAY' `glIndexPointer' `GL_INDEX_LOGIC_OP' `glLogicOp' `GL_LIGHT'I `glLightModel', `glLight' `GL_LIGHTING' `glMaterial', `glLightModel', `glLight' `GL_LINE_SMOOTH' `glLineWidth' `GL_LINE_STIPPLE' `glLineStipple' `GL_MAP1_COLOR_4' `glMap1' `GL_MAP1_INDEX' `glMap1' `GL_MAP1_NORMAL' `glMap1' `GL_MAP1_TEXTURE_COORD_1' `glMap1' `GL_MAP1_TEXTURE_COORD_2' `glMap1' `GL_MAP1_TEXTURE_COORD_3' `glMap1' `GL_MAP1_TEXTURE_COORD_4' `glMap1' `GL_MAP2_COLOR_4' `glMap2' `GL_MAP2_INDEX' `glMap2' `GL_MAP2_NORMAL' `glMap2' `GL_MAP2_TEXTURE_COORD_1' `glMap2' `GL_MAP2_TEXTURE_COORD_2' `glMap2' `GL_MAP2_TEXTURE_COORD_3' `glMap2' `GL_MAP2_TEXTURE_COORD_4' `glMap2' `GL_MAP2_VERTEX_3' `glMap2' `GL_MAP2_VERTEX_4' `glMap2' `GL_MINMAX' `glMinmax' `GL_MULTISAMPLE' `glSampleCoverage' `GL_NORMAL_ARRAY' `glNormalPointer' `GL_NORMALIZE' `glNormal' `GL_POINT_SMOOTH' `glPointSize' `GL_POINT_SPRITE' `glEnable' `GL_POLYGON_SMOOTH' `glPolygonMode' `GL_POLYGON_OFFSET_FILL' `glPolygonOffset' `GL_POLYGON_OFFSET_LINE' `glPolygonOffset' `GL_POLYGON_OFFSET_POINT' `glPolygonOffset' `GL_POLYGON_STIPPLE' `glPolygonStipple' `GL_POST_COLOR_MATRIX_COLOR_TABLE' `glColorTable' `GL_POST_CONVOLUTION_COLOR_TABLE' `glColorTable' `GL_RESCALE_NORMAL' `glNormal' `GL_SAMPLE_ALPHA_TO_COVERAGE' `glSampleCoverage' `GL_SAMPLE_ALPHA_TO_ONE' `glSampleCoverage' `GL_SAMPLE_COVERAGE' `glSampleCoverage' `GL_SCISSOR_TEST' `glScissor' `GL_SECONDARY_COLOR_ARRAY' `glSecondaryColorPointer' `GL_SEPARABLE_2D' `glSeparableFilter2D' `GL_STENCIL_TEST' `glStencilFunc', `glStencilOp' `GL_TEXTURE_1D' `glTexImage1D' `GL_TEXTURE_2D' `glTexImage2D' `GL_TEXTURE_3D' `glTexImage3D' `GL_TEXTURE_COORD_ARRAY' `glTexCoordPointer' `GL_TEXTURE_CUBE_MAP' `glTexImage2D' `GL_TEXTURE_GEN_Q' `glTexGen' `GL_TEXTURE_GEN_R' `glTexGen' `GL_TEXTURE_GEN_S' `glTexGen' `GL_TEXTURE_GEN_T' `glTexGen' `GL_VERTEX_ARRAY' `glVertexPointer' `GL_VERTEX_PROGRAM_POINT_SIZE' `glEnable' `GL_VERTEX_PROGRAM_TWO_SIDE' `glEnable' `GL_INVALID_ENUM' is generated if CAP is not an accepted value. `GL_INVALID_OPERATION' is generated if `glIsEnabled' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsList (list GLuint) -> GLboolean)) "Determine if a name corresponds to a display list. LIST Specifies a potential display list name. `glIsList' returns `GL_TRUE' if LIST is the name of a display list and returns `GL_FALSE' if it is not, or if an error occurs. A name returned by `glGenLists', but not yet associated with a display list by calling `glNewList', is not the name of a display list. `GL_INVALID_OPERATION' is generated if `glIsList' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsProgram (program GLuint) -> GLboolean)) "Determines if a name corresponds to a program object. PROGRAM Specifies a potential program object. `glIsProgram' returns `GL_TRUE' if PROGRAM is the name of a program object previously created with `glCreateProgram' and not yet deleted with `glDeleteProgram'. If PROGRAM is zero or a non-zero value that is not the name of a program object, or if an error occurs, `glIsProgram' returns `GL_FALSE'. `GL_INVALID_OPERATION' is generated if `glIsProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsQuery (id GLuint) -> GLboolean)) "Determine if a name corresponds to a query object. ID Specifies a value that may be the name of a query object. `glIsQuery' returns `GL_TRUE' if ID is currently the name of a query object. If ID is zero, or is a non-zero value that is not currently the name of a query object, or if an error occurs, `glIsQuery' returns `GL_FALSE'. A name returned by `glGenQueries', but not yet associated with a query object by calling `glBeginQuery', is not the name of a query object. `GL_INVALID_OPERATION' is generated if `glIsQuery' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsShader (shader GLuint) -> GLboolean)) "Determines if a name corresponds to a shader object. SHADER Specifies a potential shader object. `glIsShader' returns `GL_TRUE' if SHADER is the name of a shader object previously created with `glCreateShader' and not yet deleted with `glDeleteShader'. If SHADER is zero or a non-zero value that is not the name of a shader object, or if an error occurs, `glIsShader ' returns `GL_FALSE'. `GL_INVALID_OPERATION' is generated if `glIsShader' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glIsTexture (texture GLuint) -> GLboolean)) "Determine if a name corresponds to a texture. TEXTURE Specifies a value that may be the name of a texture. `glIsTexture' returns `GL_TRUE' if TEXTURE is currently the name of a texture. If TEXTURE is zero, or is a non-zero value that is not currently the name of a texture, or if an error occurs, `glIsTexture' returns `GL_FALSE'. A name returned by `glGenTextures', but not yet associated with a texture by calling `glBindTexture', is not the name of a texture. `GL_INVALID_OPERATION' is generated if `glIsTexture' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLightModelf (pname GLenum) (param GLfloat) -> void) (glLightModeli (pname GLenum) (param GLint) -> void)) "Set the lighting model parameters. PNAME Specifies a single-valued lighting model parameter. `GL_LIGHT_MODEL_LOCAL_VIEWER', `GL_LIGHT_MODEL_COLOR_CONTROL', and `GL_LIGHT_MODEL_TWO_SIDE' are accepted. PARAM Specifies the value that PARAM will be set to. `glLightModel' sets the lighting model parameter. PNAME names a parameter and PARAMS gives the new value. There are three lighting model parameters: `GL_LIGHT_MODEL_AMBIENT' PARAMS contains four integer or floating-point values that specify the ambient RGBA intensity of the entire scene. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient scene intensity is (0.2, 0.2, 0.2, 1.0). `GL_LIGHT_MODEL_COLOR_CONTROL' PARAMS must be either `GL_SEPARATE_SPECULAR_COLOR' or `GL_SINGLE_COLOR'. `GL_SINGLE_COLOR' specifies that a single color is generated from the lighting computation for a vertex. `GL_SEPARATE_SPECULAR_COLOR' specifies that the specular color computation of lighting be stored separately from the remainder of the lighting computation. The specular color is summed into the generated fragment's color after the application of texture mapping (if enabled). The initial value is `GL_SINGLE_COLOR'. `GL_LIGHT_MODEL_LOCAL_VIEWER' PARAMS is a single integer or floating-point value that specifies how specular reflection angles are computed. If PARAMS is 0 (or 0.0), specular reflection angles take the view direction to be parallel to and in the direction of the -Z axis, regardless of the location of the vertex in eye coordinates. Otherwise, specular reflections are computed from the origin of the eye coordinate system. The initial value is 0. `GL_LIGHT_MODEL_TWO_SIDE' PARAMS is a single integer or floating-point value that specifies whether one- or two-sided lighting calculations are done for polygons. It has no effect on the lighting calculations for points, lines, or bitmaps. If PARAMS is 0 (or 0.0), one-sided lighting is specified, and only the FRONT material parameters are used in the lighting equation. Otherwise, two-sided lighting is specified. In this case, vertices of back-facing polygons are lighted using the BACK material parameters and have their normals reversed before the lighting equation is evaluated. Vertices of front-facing polygons are always lighted using the FRONT material parameters, with no change to their normals. The initial value is 0. In RGBA mode, the lighted color of a vertex is the sum of the material emission intensity, the product of the material ambient reflectance and the lighting model full-scene ambient intensity, and the contribution of each enabled light source. Each light source contributes the sum of three terms: ambient, diffuse, and specular. The ambient light source contribution is the product of the material ambient reflectance and the light's ambient intensity. The diffuse light source contribution is the product of the material diffuse reflectance, the light's diffuse intensity, and the dot product of the vertex's normal with the normalized vector from the vertex to the light source. The specular light source contribution is the product of the material specular reflectance, the light's specular intensity, and the dot product of the normalized vertex-to-eye and vertex-to-light vectors, raised to the power of the shininess of the material. All three light source contributions are attenuated equally based on the distance from the vertex to the light source and on light source direction, spread exponent, and spread cutoff angle. All dot products are replaced with 0 if they evaluate to a negative value. The alpha component of the resulting lighted color is set to the alpha value of the material diffuse reflectance. In color index mode, the value of the lighted index of a vertex ranges from the ambient to the specular values passed to `glMaterial' using `GL_COLOR_INDEXES'. Diffuse and specular coefficients, computed with a (.30, .59, .11) weighting of the lights' colors, the shininess of the material, and the same reflection and attenuation equations as in the RGBA case, determine how much above ambient the resulting index is. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_ENUM' is generated if PNAME is `GL_LIGHT_MODEL_COLOR_CONTROL' and PARAMS is not one of `GL_SINGLE_COLOR' or `GL_SEPARATE_SPECULAR_COLOR'. `GL_INVALID_OPERATION' is generated if `glLightModel' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLightf (light GLenum) (pname GLenum) (param GLfloat) -> void) (glLighti (light GLenum) (pname GLenum) (param GLint) -> void)) "Set light source parameters. LIGHT Specifies a light. The number of lights depends on the implementation, but at least eight lights are supported. They are identified by symbolic names of the form `GL_LIGHT' I , where i ranges from 0 to the value of `GL_MAX_LIGHTS' - 1. PNAME Specifies a single-valued light source parameter for LIGHT. `GL_SPOT_EXPONENT', `GL_SPOT_CUTOFF', `GL_CONSTANT_ATTENUATION', `GL_LINEAR_ATTENUATION', and `GL_QUADRATIC_ATTENUATION' are accepted. PARAM Specifies the value that parameter PNAME of light source LIGHT will be set to. `glLight' sets the values of individual light source parameters. LIGHT names the light and is a symbolic name of the form `GL_LIGHT'I , where i ranges from 0 to the value of `GL_MAX_LIGHTS' - 1. PNAME specifies one of ten light source parameters, again by symbolic name. PARAMS is either a single value or a pointer to an array that contains the new values. To enable and disable lighting calculation, call `glEnable' and `glDisable' with argument `GL_LIGHTING'. Lighting is initially disabled. When it is enabled, light sources that are enabled contribute to the lighting calculation. Light source I is enabled and disabled using `glEnable' and `glDisable' with argument `GL_LIGHT'I . The ten light parameters are as follows: `GL_AMBIENT' PARAMS contains four integer or floating-point values that specify the ambient RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient light intensity is (0, 0, 0, 1). `GL_DIFFUSE' PARAMS contains four integer or floating-point values that specify the diffuse RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for `GL_LIGHT0' is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 1). `GL_SPECULAR' PARAMS contains four integer or floating-point values that specify the specular RGBA intensity of the light. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial value for `GL_LIGHT0' is (1, 1, 1, 1); for other lights, the initial value is (0, 0, 0, 1). `GL_POSITION' PARAMS contains four integer or floating-point values that specify the position of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The position is transformed by the modelview matrix when `glLight' is called (just as if it were a point), and it is stored in eye coordinates. If the W component of the position is 0, the light is treated as a directional source. Diffuse and specular lighting calculations take the light's direction, but not its actual position, into account, and attenuation is disabled. Otherwise, diffuse and specular lighting calculations are based on the actual location of the light in eye coordinates, and attenuation is enabled. The initial position is (0, 0, 1, 0); thus, the initial light source is directional, parallel to, and in the direction of the -Z axis. `GL_SPOT_DIRECTION' PARAMS contains three integer or floating-point values that specify the direction of the light in homogeneous object coordinates. Both integer and floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The spot direction is transformed by the upper 3x3 of the modelview matrix when `glLight' is called, and it is stored in eye coordinates. It is significant only when `GL_SPOT_CUTOFF' is not 180, which it is initially. The initial direction is (0,0-1) . `GL_SPOT_EXPONENT' PARAMS is a single integer or floating-point value that specifies the intensity distribution of the light. Integer and floating-point values are mapped directly. Only values in the range [0,128] are accepted. Effective light intensity is attenuated by the cosine of the angle between the direction of the light and the direction from the light to the vertex being lighted, raised to the power of the spot exponent. Thus, higher spot exponents result in a more focused light source, regardless of the spot cutoff angle (see `GL_SPOT_CUTOFF', next paragraph). The initial spot exponent is 0, resulting in uniform light distribution. `GL_SPOT_CUTOFF' PARAMS is a single integer or floating-point value that specifies the maximum spread angle of a light source. Integer and floating-point values are mapped directly. Only values in the range [0,90] and the special value 180 are accepted. If the angle between the direction of the light and the direction from the light to the vertex being lighted is greater than the spot cutoff angle, the light is completely masked. Otherwise, its intensity is controlled by the spot exponent and the attenuation factors. The initial spot cutoff is 180, resulting in uniform light distribution. `GL_CONSTANT_ATTENUATION' `GL_LINEAR_ATTENUATION' `GL_QUADRATIC_ATTENUATION' PARAMS is a single integer or floating-point value that specifies one of the three light attenuation factors. Integer and floating-point values are mapped directly. Only nonnegative values are accepted. If the light is positional, rather than directional, its intensity is attenuated by the reciprocal of the sum of the constant factor, the linear factor times the distance between the light and the vertex being lighted, and the quadratic factor times the square of the same distance. The initial attenuation factors are (1, 0, 0), resulting in no attenuation. `GL_INVALID_ENUM' is generated if either LIGHT or PNAME is not an accepted value. `GL_INVALID_VALUE' is generated if a spot exponent value is specified outside the range [0,128] , or if spot cutoff is specified outside the range [0,90] (except for the special value 180), or if a negative attenuation factor is specified. `GL_INVALID_OPERATION' is generated if `glLight' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLineStipple (factor GLint) (pattern GLushort) -> void)) "Specify the line stipple pattern. FACTOR Specifies a multiplier for each bit in the line stipple pattern. If FACTOR is 3, for example, each bit in the pattern is used three times before the next bit in the pattern is used. FACTOR is clamped to the range [1, 256] and defaults to 1. PATTERN Specifies a 16-bit integer whose bit pattern determines which fragments of a line will be drawn when the line is rasterized. Bit zero is used first; the default pattern is all 1's. Line stippling masks out certain fragments produced by rasterization; those fragments will not be drawn. The masking is achieved by using three parameters: the 16-bit line stipple pattern PATTERN, the repeat count FACTOR, and an integer stipple counter S . Counter S is reset to 0 whenever `glBegin' is called and before each line segment of a `glBegin'(`GL_LINES')/`glEnd' sequence is generated. It is incremented after each fragment of a unit width aliased line segment is generated or after each I fragments of an I width line segment are generated. The I fragments associated with count S are masked out if PATTERN bit (S/FACTOR,)%16 is 0, otherwise these fragments are sent to the frame buffer. Bit zero of PATTERN is the least significant bit. Antialiased lines are treated as a sequence of 1×WIDTH rectangles for purposes of stippling. Whether rectangle S is rasterized or not depends on the fragment rule described for aliased lines, counting rectangles rather than groups of fragments. To enable and disable line stippling, call `glEnable' and `glDisable' with argument `GL_LINE_STIPPLE'. When enabled, the line stipple pattern is applied as described above. When disabled, it is as if the pattern were all 1's. Initially, line stippling is disabled. `GL_INVALID_OPERATION' is generated if `glLineStipple' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLineWidth (width GLfloat) -> void)) "Specify the width of rasterized lines. WIDTH Specifies the width of rasterized lines. The initial value is 1. `glLineWidth' specifies the rasterized width of both aliased and antialiased lines. Using a line width other than 1 has different effects, depending on whether line antialiasing is enabled. To enable and disable line antialiasing, call `glEnable' and `glDisable' with argument `GL_LINE_SMOOTH'. Line antialiasing is initially disabled. If line antialiasing is disabled, the actual width is determined by rounding the supplied width to the nearest integer. (If the rounding results in the value 0, it is as if the line width were 1.) If ∣ΔX,∣>=∣ΔY,∣ , I pixels are filled in each column that is rasterized, where I is the rounded value of WIDTH. Otherwise, I pixels are filled in each row that is rasterized. If antialiasing is enabled, line rasterization produces a fragment for each pixel square that intersects the region lying within the rectangle having width equal to the current line width, length equal to the actual length of the line, and centered on the mathematical line segment. The coverage value for each fragment is the window coordinate area of the intersection of the rectangular region with the corresponding pixel square. This value is saved and used in the final rasterization step. Not all widths can be supported when line antialiasing is enabled. If an unsupported width is requested, the nearest supported width is used. Only width 1 is guaranteed to be supported; others depend on the implementation. Likewise, there is a range for aliased line widths as well. To query the range of supported widths and the size difference between supported widths within the range, call `glGet' with arguments `GL_ALIASED_LINE_WIDTH_RANGE', `GL_SMOOTH_LINE_WIDTH_RANGE', and `GL_SMOOTH_LINE_WIDTH_GRANULARITY'. `GL_INVALID_VALUE' is generated if WIDTH is less than or equal to 0. `GL_INVALID_OPERATION' is generated if `glLineWidth' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLinkProgram (program GLuint) -> void)) "Links a program object. PROGRAM Specifies the handle of the program object to be linked. `glLinkProgram' links the program object specified by PROGRAM. If any shader objects of type `GL_VERTEX_SHADER' are attached to PROGRAM, they will be used to create an executable that will run on the programmable vertex processor. If any shader objects of type `GL_FRAGMENT_SHADER' are attached to PROGRAM, they will be used to create an executable that will run on the programmable fragment processor. The status of the link operation will be stored as part of the program object's state. This value will be set to `GL_TRUE' if the program object was linked without errors and is ready for use, and `GL_FALSE' otherwise. It can be queried by calling `glGetProgram' with arguments PROGRAM and `GL_LINK_STATUS'. As a result of a successful link operation, all active user-defined uniform variables belonging to PROGRAM will be initialized to 0, and each of the program object's active uniform variables will be assigned a location that can be queried by calling `glGetUniformLocation'. Also, any active user-defined attribute variables that have not been bound to a generic vertex attribute index will be bound to one at this time. Linking of a program object can fail for a number of reasons as specified in the OPENGL SHADING LANGUAGE SPECIFICATION. The following lists some of the conditions that will cause a link error. * The storage limit for uniform variables has been exceeded. * The number of active uniform variables supported by the implementation has been exceeded. * The `main' function is missing for the vertex shader or the fragment shader. * A varying variable actually used in the fragment shader is not declared in the same way (or is not declared at all) in the vertex shader. * A reference to a function or variable name is unresolved. * A shared global is declared with two different types or two different initial values. * One or more of the attached shader objects has not been successfully compiled. * Binding a generic attribute matrix caused some rows of the matrix to fall outside the allowed maximum of `GL_MAX_VERTEX_ATTRIBS'. * Not enough contiguous vertex attribute slots could be found to bind attribute matrices. When a program object has been successfully linked, the program object can be made part of current state by calling `glUseProgram'. Whether or not the link operation was successful, the program object's information log will be overwritten. The information log can be retrieved by calling `glGetProgramInfoLog'. `glLinkProgram' will also install the generated executables as part of the current rendering state if the link operation was successful and the specified program object is already currently in use as a result of a previous call to `glUseProgram'. If the program object currently in use is relinked unsuccessfully, its link status will be set to `GL_FALSE' , but the executables and associated state will remain part of the current state until a subsequent call to `glUseProgram' removes it from use. After it is removed from use, it cannot be made part of current state until it has been successfully relinked. If PROGRAM contains shader objects of type `GL_VERTEX_SHADER' but does not contain shader objects of type `GL_FRAGMENT_SHADER', the vertex shader will be linked against the implicit interface for fixed functionality fragment processing. Similarly, if PROGRAM contains shader objects of type `GL_FRAGMENT_SHADER' but it does not contain shader objects of type `GL_VERTEX_SHADER', the fragment shader will be linked against the implicit interface for fixed functionality vertex processing. The program object's information log is updated and the program is generated at the time of the link operation. After the link operation, applications are free to modify attached shader objects, compile attached shader objects, detach shader objects, delete shader objects, and attach additional shader objects. None of these operations affects the information log or the program that is part of the program object. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if `glLinkProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glListBase (base GLuint) -> void)) "Set the display-list base for . BASE Specifies an integer offset that will be added to `glCallLists' offsets to generate display-list names. The initial value is 0. `glCallLists' specifies an array of offsets. Display-list names are generated by adding BASE to each offset. Names that reference valid display lists are executed; the others are ignored. `GL_INVALID_OPERATION' is generated if `glListBase' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLoadIdentity -> void)) "Replace the current matrix with the identity matrix. `glLoadIdentity' replaces the current matrix with the identity matrix. It is semantically equivalent to calling `glLoadMatrix' with the identity matrix ((1 0 0 0), (0 1 0 0), (0 0 1 0), (0 0 0 1),,) but in some cases it is more efficient. `GL_INVALID_OPERATION' is generated if `glLoadIdentity' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLoadMatrixf (m const-GLfloat-*) -> void)) "Replace the current matrix with the specified matrix. M Specifies a pointer to 16 consecutive values, which are used as the elements of a 4×4 column-major matrix. `glLoadMatrix' replaces the current matrix with the one whose elements are specified by M. The current matrix is the projection matrix, modelview matrix, or texture matrix, depending on the current matrix mode (see `glMatrixMode'). The current matrix, M, defines a transformation of coordinates. For instance, assume M refers to the modelview matrix. If V=(V\u2061[0,],V\u2061[1,]V\u2061[2,]V\u2061[3,]) is the set of object coordinates of a vertex, and M points to an array of 16 single- or double-precision floating-point values M={M\u2061[0,],M\u2061[1,]...M\u2061[15,]} , then the modelview transformation M\u2061(V,) does the following: M\u2061(V,)=((M\u2061[0,] M\u2061[4,] M\u2061[8,] M\u2061[12,]), (M\u2061[1,] M\u2061[5,] M\u2061[9,] M\u2061[13,]), (M\u2061[2,] M\u2061[6,] M\u2061[10,] M\u2061[14,]), (M\u2061[3,] M\u2061[7,] M\u2061[11,] M\u2061[15,]),)×((V\u2061[0,]), (V\u2061[1,]), (V\u2061[2,]), (V\u2061[3,]),) Projection and texture transformations are similarly defined. `GL_INVALID_OPERATION' is generated if `glLoadMatrix' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLoadName (name GLuint) -> void)) "Load a name onto the name stack. NAME Specifies a name that will replace the top value on the name stack. The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers and is initially empty. `glLoadName' causes NAME to replace the value on the top of the name stack. The name stack is always empty while the render mode is not `GL_SELECT'. Calls to `glLoadName' while the render mode is not `GL_SELECT' are ignored. `GL_INVALID_OPERATION' is generated if `glLoadName' is called while the name stack is empty. `GL_INVALID_OPERATION' is generated if `glLoadName' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLoadTransposeMatrixf (m const-GLfloat-*) -> void)) "Replace the current matrix with the specified row-major ordered matrix. M Specifies a pointer to 16 consecutive values, which are used as the elements of a 4×4 row-major matrix. `glLoadTransposeMatrix' replaces the current matrix with the one whose elements are specified by M. The current matrix is the projection matrix, modelview matrix, or texture matrix, depending on the current matrix mode (see `glMatrixMode'). The current matrix, M, defines a transformation of coordinates. For instance, assume M refers to the modelview matrix. If V=(V\u2061[0,],V\u2061[1,]V\u2061[2,]V\u2061[3,]) is the set of object coordinates of a vertex, and M points to an array of 16 single- or double-precision floating-point values M={M\u2061[0,],M\u2061[1,]...M\u2061[15,]} , then the modelview transformation M\u2061(V,) does the following: M\u2061(V,)=((M\u2061[0,] M\u2061[1,] M\u2061[2,] M\u2061[3,]), (M\u2061[4,] M\u2061[5,] M\u2061[6,] M\u2061[7,]), (M\u2061[8,] M\u2061[9,] M\u2061[10,] M\u2061[11,]), (M\u2061[12,] M\u2061[13,] M\u2061[14,] M\u2061[15,]),)×((V\u2061[0,]), (V\u2061[1,]), (V\u2061[2,]), (V\u2061[3,]),) Projection and texture transformations are similarly defined. Calling `glLoadTransposeMatrix' with matrix M is identical in operation to `glLoadMatrix' with M^T , where T represents the transpose. `GL_INVALID_OPERATION' is generated if `glLoadTransposeMatrix' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glLogicOp (opcode GLenum) -> void)) "Specify a logical pixel operation for color index rendering. OPCODE Specifies a symbolic constant that selects a logical operation. The following symbols are accepted: `GL_CLEAR', `GL_SET', `GL_COPY', `GL_COPY_INVERTED', `GL_NOOP', `GL_INVERT', `GL_AND', `GL_NAND', `GL_OR', `GL_NOR', `GL_XOR', `GL_EQUIV', `GL_AND_REVERSE', `GL_AND_INVERTED', `GL_OR_REVERSE', and `GL_OR_INVERTED'. The initial value is `GL_COPY'. `glLogicOp' specifies a logical operation that, when enabled, is applied between the incoming color index or RGBA color and the color index or RGBA color at the corresponding location in the frame buffer. To enable or disable the logical operation, call `glEnable' and `glDisable' using the symbolic constant `GL_COLOR_LOGIC_OP' for RGBA mode or `GL_INDEX_LOGIC_OP' for color index mode. The initial value is disabled for both operations. *Opcode* *Resulting Operation* `GL_CLEAR' 0 `GL_SET' 1 `GL_COPY' s `GL_COPY_INVERTED' ~s `GL_NOOP' d `GL_INVERT' ~d `GL_AND' s & d `GL_NAND' ~(s & d) `GL_OR' s | d `GL_NOR' ~(s | d) `GL_XOR' s ^ d `GL_EQUIV' ~(s ^ d) `GL_AND_REVERSE' s & ~d `GL_AND_INVERTED' ~s & d `GL_OR_REVERSE' s | ~d `GL_OR_INVERTED' ~s | d OPCODE is a symbolic constant chosen from the list above. In the explanation of the logical operations, S represents the incoming color index and D represents the index in the frame buffer. Standard C-language operators are used. As these bitwise operators suggest, the logical operation is applied independently to each bit pair of the source and destination indices or colors. `GL_INVALID_ENUM' is generated if OPCODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glLogicOp' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMap1f (target GLenum) (u1 GLfloat) (u2 GLfloat) (stride GLint) (order GLint) (points const-GLfloat-*) -> void)) "Define a one-dimensional evaluator. TARGET Specifies the kind of values that are generated by the evaluator. Symbolic constants `GL_MAP1_VERTEX_3', `GL_MAP1_VERTEX_4', `GL_MAP1_INDEX', `GL_MAP1_COLOR_4', `GL_MAP1_NORMAL', `GL_MAP1_TEXTURE_COORD_1', `GL_MAP1_TEXTURE_COORD_2', `GL_MAP1_TEXTURE_COORD_3', and `GL_MAP1_TEXTURE_COORD_4' are accepted. U1 U2 Specify a linear mapping of U , as presented to `glEvalCoord1', to U^ , the variable that is evaluated by the equations specified by this command. STRIDE Specifies the number of floats or doubles between the beginning of one control point and the beginning of the next one in the data structure referenced in POINTS. This allows control points to be embedded in arbitrary data structures. The only constraint is that the values for a particular control point must occupy contiguous memory locations. ORDER Specifies the number of control points. Must be positive. POINTS Specifies a pointer to the array of control points. Evaluators provide a way to use polynomial or rational polynomial mapping to produce vertices, normals, texture coordinates, and colors. The values produced by an evaluator are sent to further stages of GL processing just as if they had been presented using `glVertex', `glNormal', `glTexCoord', and `glColor' commands, except that the generated values do not update the current normal, texture coordinates, or color. All polynomial or rational polynomial splines of any degree (up to the maximum degree supported by the GL implementation) can be described using evaluators. These include almost all splines used in computer graphics: B-splines, Bezier curves, Hermite splines, and so on. Evaluators define curves based on Bernstein polynomials. Define P\u2061(U^,) as P\u2061(U^,)=ΣI=0NB_I,^N\u2061(U^,)\u2062R_I where R_I is a control point and B_I,^N\u2061(U^,) is the I th Bernstein polynomial of degree N (ORDER = N+1 ): B_I,^N\u2061(U^,)=((N), (I),,)\u2062U^,^I\u2062(1-U^,)^N-I,, Recall that 0^0==1 and ((N), (0),,)==1 `glMap1' is used to define the basis and to specify what kind of values are produced. Once defined, a map can be enabled and disabled by calling `glEnable' and `glDisable' with the map name, one of the nine predefined values for TARGET described below. `glEvalCoord1' evaluates the one-dimensional maps that are enabled. When `glEvalCoord1' presents a value U , the Bernstein functions are evaluated using U^ , where U^=U-U1,/U2-U1, TARGET is a symbolic constant that indicates what kind of control points are provided in POINTS, and what output is generated when the map is evaluated. It can assume one of nine predefined values: `GL_MAP1_VERTEX_3' Each control point is three floating-point values representing X , Y , and Z . Internal `glVertex3' commands are generated when the map is evaluated. `GL_MAP1_VERTEX_4' Each control point is four floating-point values representing X , Y , Z , and W . Internal `glVertex4' commands are generated when the map is evaluated. `GL_MAP1_INDEX' Each control point is a single floating-point value representing a color index. Internal `glIndex' commands are generated when the map is evaluated but the current index is not updated with the value of these `glIndex' commands. `GL_MAP1_COLOR_4' Each control point is four floating-point values representing red, green, blue, and alpha. Internal `glColor4' commands are generated when the map is evaluated but the current color is not updated with the value of these `glColor4' commands. `GL_MAP1_NORMAL' Each control point is three floating-point values representing the X , Y , and Z components of a normal vector. Internal `glNormal' commands are generated when the map is evaluated but the current normal is not updated with the value of these `glNormal' commands. `GL_MAP1_TEXTURE_COORD_1' Each control point is a single floating-point value representing the S texture coordinate. Internal `glTexCoord1' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP1_TEXTURE_COORD_2' Each control point is two floating-point values representing the S and T texture coordinates. Internal `glTexCoord2' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP1_TEXTURE_COORD_3' Each control point is three floating-point values representing the S , T , and R texture coordinates. Internal `glTexCoord3' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP1_TEXTURE_COORD_4' Each control point is four floating-point values representing the S , T , R , and Q texture coordinates. Internal `glTexCoord4' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. STRIDE, ORDER, and POINTS define the array addressing for accessing the control points. POINTS is the location of the first control point, which occupies one, two, three, or four contiguous memory locations, depending on which map is being defined. ORDER is the number of control points in the array. STRIDE specifies how many float or double locations to advance the internal memory pointer to reach the next control point. `GL_INVALID_ENUM' is generated if TARGET is not an accepted value. `GL_INVALID_VALUE' is generated if U1 is equal to U2. `GL_INVALID_VALUE' is generated if STRIDE is less than the number of values in a control point. `GL_INVALID_VALUE' is generated if ORDER is less than 1 or greater than the return value of `GL_MAX_EVAL_ORDER'. `GL_INVALID_OPERATION' is generated if `glMap1' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if `glMap1' is called and the value of `GL_ACTIVE_TEXTURE' is not `GL_TEXTURE0'.") (define-gl-procedures ((glMap2f (target GLenum) (u1 GLfloat) (u2 GLfloat) (ustride GLint) (uorder GLint) (v1 GLfloat) (v2 GLfloat) (vstride GLint) (vorder GLint) (points const-GLfloat-*) -> void)) "Define a two-dimensional evaluator. TARGET Specifies the kind of values that are generated by the evaluator. Symbolic constants `GL_MAP2_VERTEX_3', `GL_MAP2_VERTEX_4', `GL_MAP2_INDEX', `GL_MAP2_COLOR_4', `GL_MAP2_NORMAL', `GL_MAP2_TEXTURE_COORD_1', `GL_MAP2_TEXTURE_COORD_2', `GL_MAP2_TEXTURE_COORD_3', and `GL_MAP2_TEXTURE_COORD_4' are accepted. U1 U2 Specify a linear mapping of U , as presented to `glEvalCoord2', to U^ , one of the two variables that are evaluated by the equations specified by this command. Initially, U1 is 0 and U2 is 1. USTRIDE Specifies the number of floats or doubles between the beginning of control point R_IJ and the beginning of control point R_(I+1,)\u2062J, , where I and J are the U and V control point indices, respectively. This allows control points to be embedded in arbitrary data structures. The only constraint is that the values for a particular control point must occupy contiguous memory locations. The initial value of USTRIDE is 0. UORDER Specifies the dimension of the control point array in the U axis. Must be positive. The initial value is 1. V1 V2 Specify a linear mapping of V , as presented to `glEvalCoord2', to V^ , one of the two variables that are evaluated by the equations specified by this command. Initially, V1 is 0 and V2 is 1. VSTRIDE Specifies the number of floats or doubles between the beginning of control point R_IJ and the beginning of control point R_I\u2061(J+1,), , where I and J are the U and V control point indices, respectively. This allows control points to be embedded in arbitrary data structures. The only constraint is that the values for a particular control point must occupy contiguous memory locations. The initial value of VSTRIDE is 0. VORDER Specifies the dimension of the control point array in the V axis. Must be positive. The initial value is 1. POINTS Specifies a pointer to the array of control points. Evaluators provide a way to use polynomial or rational polynomial mapping to produce vertices, normals, texture coordinates, and colors. The values produced by an evaluator are sent on to further stages of GL processing just as if they had been presented using `glVertex', `glNormal', `glTexCoord', and `glColor' commands, except that the generated values do not update the current normal, texture coordinates, or color. All polynomial or rational polynomial splines of any degree (up to the maximum degree supported by the GL implementation) can be described using evaluators. These include almost all surfaces used in computer graphics, including B-spline surfaces, NURBS surfaces, Bezier surfaces, and so on. Evaluators define surfaces based on bivariate Bernstein polynomials. Define P\u2061(U^,V^) as P\u2061(U^,V^)=ΣI=0NΣJ=0MB_I,^N\u2061(U^,)\u2062B_J,^M\u2061(V^,)\u2062R_IJ where R_IJ is a control point, B_I,^N\u2061(U^,) is the I th Bernstein polynomial of degree N (UORDER = N+1 ) B_I,^N\u2061(U^,)=((N), (I),,)\u2062U^,^I\u2062(1-U^,)^N-I,, and B_J,^M\u2061(V^,) is the J th Bernstein polynomial of degree M (VORDER = M+1 ) B_J,^M\u2061(V^,)=((M), (J),,)\u2062V^,^J\u2062(1-V^,)^M-J,, Recall that 0^0==1 and ((N), (0),,)==1 `glMap2' is used to define the basis and to specify what kind of values are produced. Once defined, a map can be enabled and disabled by calling `glEnable' and `glDisable' with the map name, one of the nine predefined values for TARGET, described below. When `glEvalCoord2' presents values U and V , the bivariate Bernstein polynomials are evaluated using U^ and V^ , where U^=U-U1,/U2-U1, V^=V-V1,/V2-V1, TARGET is a symbolic constant that indicates what kind of control points are provided in POINTS, and what output is generated when the map is evaluated. It can assume one of nine predefined values: `GL_MAP2_VERTEX_3' Each control point is three floating-point values representing X , Y , and Z . Internal `glVertex3' commands are generated when the map is evaluated. `GL_MAP2_VERTEX_4' Each control point is four floating-point values representing X , Y , Z , and W . Internal `glVertex4' commands are generated when the map is evaluated. `GL_MAP2_INDEX' Each control point is a single floating-point value representing a color index. Internal `glIndex' commands are generated when the map is evaluated but the current index is not updated with the value of these `glIndex' commands. `GL_MAP2_COLOR_4' Each control point is four floating-point values representing red, green, blue, and alpha. Internal `glColor4' commands are generated when the map is evaluated but the current color is not updated with the value of these `glColor4' commands. `GL_MAP2_NORMAL' Each control point is three floating-point values representing the X , Y , and Z components of a normal vector. Internal `glNormal' commands are generated when the map is evaluated but the current normal is not updated with the value of these `glNormal' commands. `GL_MAP2_TEXTURE_COORD_1' Each control point is a single floating-point value representing the S texture coordinate. Internal `glTexCoord1' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP2_TEXTURE_COORD_2' Each control point is two floating-point values representing the S and T texture coordinates. Internal `glTexCoord2' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP2_TEXTURE_COORD_3' Each control point is three floating-point values representing the S , T , and R texture coordinates. Internal `glTexCoord3' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. `GL_MAP2_TEXTURE_COORD_4' Each control point is four floating-point values representing the S , T , R , and Q texture coordinates. Internal `glTexCoord4' commands are generated when the map is evaluated but the current texture coordinates are not updated with the value of these `glTexCoord' commands. USTRIDE, UORDER, VSTRIDE, VORDER, and POINTS define the array addressing for accessing the control points. POINTS is the location of the first control point, which occupies one, two, three, or four contiguous memory locations, depending on which map is being defined. There are UORDER×VORDER control points in the array. USTRIDE specifies how many float or double locations are skipped to advance the internal memory pointer from control point R_I\u2062J, to control point R_(I+1,)\u2062J, . VSTRIDE specifies how many float or double locations are skipped to advance the internal memory pointer from control point R_I\u2062J, to control point R_I\u2061(J+1,), . `GL_INVALID_ENUM' is generated if TARGET is not an accepted value. `GL_INVALID_VALUE' is generated if U1 is equal to U2, or if V1 is equal to V2. `GL_INVALID_VALUE' is generated if either USTRIDE or VSTRIDE is less than the number of values in a control point. `GL_INVALID_VALUE' is generated if either UORDER or VORDER is less than 1 or greater than the return value of `GL_MAX_EVAL_ORDER'. `GL_INVALID_OPERATION' is generated if `glMap2' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_INVALID_OPERATION' is generated if `glMap2' is called and the value of `GL_ACTIVE_TEXTURE' is not `GL_TEXTURE0'.") (define-gl-procedures ((glMapBuffer (target GLenum) (access GLenum) -> void-*) (glUnmapBuffer (target GLenum) -> GLboolean)) "Map a buffer object's data store. TARGET Specifies the target buffer object being mapped. The symbolic constant must be `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. ACCESS Specifies the access policy, indicating whether it will be possible to read from, write to, or both read from and write to the buffer object's mapped data store. The symbolic constant must be `GL_READ_ONLY', `GL_WRITE_ONLY', or `GL_READ_WRITE'. `glMapBuffer' maps to the client's address space the entire data store of the buffer object currently bound to TARGET. The data can then be directly read and/or written relative to the returned pointer, depending on the specified ACCESS policy. If the GL is unable to map the buffer object's data store, `glMapBuffer' generates an error and returns `NULL'. This may occur for system-specific reasons, such as low virtual memory availability. If a mapped data store is accessed in a way inconsistent with the specified ACCESS policy, no error is generated, but performance may be negatively impacted and system errors, including program termination, may result. Unlike the USAGE parameter of `glBufferData', ACCESS is not a hint, and does in fact constrain the usage of the mapped data store on some GL implementations. In order to achieve the highest performance available, a buffer object's data store should be used in ways consistent with both its specified USAGE and ACCESS parameters. A mapped data store must be unmapped with `glUnmapBuffer' before its buffer object is used. Otherwise an error will be generated by any GL command that attempts to dereference the buffer object's data store. When a data store is unmapped, the pointer to its data store becomes invalid. `glUnmapBuffer' returns `GL_TRUE' unless the data store contents have become corrupt during the time the data store was mapped. This can occur for system-specific reasons that affect the availability of graphics memory, such as screen mode changes. In such situations, `GL_FALSE' is returned and the data store contents are undefined. An application must detect this rare condition and reinitialize the data store. A buffer object's mapped data store is automatically unmapped when the buffer object is deleted or its data store is recreated with `glBufferData'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_ARRAY_BUFFER', `GL_ELEMENT_ARRAY_BUFFER', `GL_PIXEL_PACK_BUFFER', or `GL_PIXEL_UNPACK_BUFFER'. `GL_INVALID_ENUM' is generated if ACCESS is not `GL_READ_ONLY', `GL_WRITE_ONLY', or `GL_READ_WRITE'. `GL_OUT_OF_MEMORY' is generated when `glMapBuffer' is executed if the GL is unable to map the buffer object's data store. This may occur for a variety of system-specific reasons, such as the absence of sufficient remaining virtual memory. `GL_INVALID_OPERATION' is generated if the reserved buffer object name 0 is bound to TARGET. `GL_INVALID_OPERATION' is generated if `glMapBuffer' is executed for a buffer object whose data store is already mapped. `GL_INVALID_OPERATION' is generated if `glUnmapBuffer' is executed for a buffer object whose data store is not currently mapped. `GL_INVALID_OPERATION' is generated if `glMapBuffer' or `glUnmapBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMapGrid1f (un GLint) (u1 GLfloat) (u2 GLfloat) -> void) (glMapGrid2f (un GLint) (u1 GLfloat) (u2 GLfloat) (vn GLint) (v1 GLfloat) (v2 GLfloat) -> void)) "Define a one- or two-dimensional mesh. UN Specifies the number of partitions in the grid range interval [U1, U2]. Must be positive. U1 U2 Specify the mappings for integer grid domain values I=0 and I=UN . VN Specifies the number of partitions in the grid range interval [V1, V2] (`glMapGrid2' only). V1 V2 Specify the mappings for integer grid domain values J=0 and J=VN (`glMapGrid2' only). `glMapGrid' and `glEvalMesh' are used together to efficiently generate and evaluate a series of evenly-spaced map domain values. `glEvalMesh' steps through the integer domain of a one- or two-dimensional grid, whose range is the domain of the evaluation maps specified by `glMap1' and `glMap2'. `glMapGrid1' and `glMapGrid2' specify the linear grid mappings between the I (or I and J ) integer grid coordinates, to the U (or U and V ) floating-point evaluation map coordinates. See `glMap1' and `glMap2' for details of how U and V coordinates are evaluated. `glMapGrid1' specifies a single linear mapping such that integer grid coordinate 0 maps exactly to U1, and integer grid coordinate UN maps exactly to U2. All other integer grid coordinates I are mapped so that U=I\u2061(U2-U1,)/UN+U1 `glMapGrid2' specifies two such linear mappings. One maps integer grid coordinate I=0 exactly to U1, and integer grid coordinate I=UN exactly to U2. The other maps integer grid coordinate J=0 exactly to V1, and integer grid coordinate J=VN exactly to V2. Other integer grid coordinates I and J are mapped such that U=I\u2061(U2-U1,)/UN+U1 V=J\u2061(V2-V1,)/VN+V1 The mappings specified by `glMapGrid' are used identically by `glEvalMesh' and `glEvalPoint'. `GL_INVALID_VALUE' is generated if either UN or VN is not positive. `GL_INVALID_OPERATION' is generated if `glMapGrid' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMaterialf (face GLenum) (pname GLenum) (param GLfloat) -> void) (glMateriali (face GLenum) (pname GLenum) (param GLint) -> void)) "Specify material parameters for the lighting model. FACE Specifies which face or faces are being updated. Must be one of `GL_FRONT', `GL_BACK', or `GL_FRONT_AND_BACK'. PNAME Specifies the single-valued material parameter of the face or faces that is being updated. Must be `GL_SHININESS'. PARAM Specifies the value that parameter `GL_SHININESS' will be set to. `glMaterial' assigns values to material parameters. There are two matched sets of material parameters. One, the FRONT-FACING set, is used to shade points, lines, bitmaps, and all polygons (when two-sided lighting is disabled), or just front-facing polygons (when two-sided lighting is enabled). The other set, BACK-FACING, is used to shade back-facing polygons only when two-sided lighting is enabled. Refer to the `glLightModel' reference page for details concerning one- and two-sided lighting calculations. `glMaterial' takes three arguments. The first, FACE, specifies whether the `GL_FRONT' materials, the `GL_BACK' materials, or both `GL_FRONT_AND_BACK' materials will be modified. The second, PNAME, specifies which of several parameters in one or both sets will be modified. The third, PARAMS, specifies what value or values will be assigned to the specified parameter. Material parameters are used in the lighting equation that is optionally applied to each vertex. The equation is discussed in the `glLightModel' reference page. The parameters that can be specified using `glMaterial', and their interpretations by the lighting equation, are as follows: `GL_AMBIENT' PARAMS contains four integer or floating-point values that specify the ambient RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial ambient reflectance for both front- and back-facing materials is (0.2, 0.2, 0.2, 1.0). `GL_DIFFUSE' PARAMS contains four integer or floating-point values that specify the diffuse RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial diffuse reflectance for both front- and back-facing materials is (0.8, 0.8, 0.8, 1.0). `GL_SPECULAR' PARAMS contains four integer or floating-point values that specify the specular RGBA reflectance of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial specular reflectance for both front- and back-facing materials is (0, 0, 0, 1). `GL_EMISSION' PARAMS contains four integer or floating-point values that specify the RGBA emitted light intensity of the material. Integer values are mapped linearly such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . Floating-point values are mapped directly. Neither integer nor floating-point values are clamped. The initial emission intensity for both front- and back-facing materials is (0, 0, 0, 1). `GL_SHININESS' PARAMS is a single integer or floating-point value that specifies the RGBA specular exponent of the material. Integer and floating-point values are mapped directly. Only values in the range [0,128] are accepted. The initial specular exponent for both front- and back-facing materials is 0. `GL_AMBIENT_AND_DIFFUSE' Equivalent to calling `glMaterial' twice with the same parameter values, once with `GL_AMBIENT' and once with `GL_DIFFUSE'. `GL_COLOR_INDEXES' PARAMS contains three integer or floating-point values specifying the color indices for ambient, diffuse, and specular lighting. These three values, and `GL_SHININESS', are the only material values used by the color index mode lighting equation. Refer to the `glLightModel' reference page for a discussion of color index lighting. `GL_INVALID_ENUM' is generated if either FACE or PNAME is not an accepted value. `GL_INVALID_VALUE' is generated if a specular exponent outside the range [0,128] is specified.") (define-gl-procedures ((glMatrixMode (mode GLenum) -> void)) "Specify which matrix is the current matrix. MODE Specifies which matrix stack is the target for subsequent matrix operations. Three values are accepted: `GL_MODELVIEW', `GL_PROJECTION', and `GL_TEXTURE'. The initial value is `GL_MODELVIEW'. Additionally, if the `ARB_imaging' extension is supported, `GL_COLOR' is also accepted. `glMatrixMode' sets the current matrix mode. MODE can assume one of four values: `GL_MODELVIEW' Applies subsequent matrix operations to the modelview matrix stack. `GL_PROJECTION' Applies subsequent matrix operations to the projection matrix stack. `GL_TEXTURE' Applies subsequent matrix operations to the texture matrix stack. `GL_COLOR' Applies subsequent matrix operations to the color matrix stack. To find out which matrix stack is currently the target of all matrix operations, call `glGet' with argument `GL_MATRIX_MODE'. The initial value is `GL_MODELVIEW'. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glMatrixMode' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMinmax (target GLenum) (internalformat GLenum) (sink GLboolean) -> void)) "Define minmax table. TARGET The minmax table whose parameters are to be set. Must be `GL_MINMAX'. INTERNALFORMAT The format of entries in the minmax table. Must be one of `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. SINK If `GL_TRUE', pixels will be consumed by the minmax process and no drawing or texture loading will take place. If `GL_FALSE', pixels will proceed to the final conversion process after minmax. When `GL_MINMAX' is enabled, the RGBA components of incoming pixels are compared to the minimum and maximum values for each component, which are stored in the two-element minmax table. (The first element stores the minima, and the second element stores the maxima.) If a pixel component is greater than the corresponding component in the maximum element, then the maximum element is updated with the pixel component value. If a pixel component is less than the corresponding component in the minimum element, then the minimum element is updated with the pixel component value. (In both cases, if the internal format of the minmax table includes luminance, then the R color component of incoming pixels is used for comparison.) The contents of the minmax table may be retrieved at a later time by calling `glGetMinmax'. The minmax operation is enabled or disabled by calling `glEnable' or `glDisable', respectively, with an argument of `GL_MINMAX'. `glMinmax' redefines the current minmax table to have entries of the format specified by INTERNALFORMAT. The maximum element is initialized with the smallest possible component values, and the minimum element is initialized with the largest possible component values. The values in the previous minmax table, if any, are lost. If SINK is `GL_TRUE', then pixels are discarded after minmax; no further processing of the pixels takes place, and no drawing, texture loading, or pixel readback will result. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_OPERATION' is generated if `glMinmax' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMultiDrawArrays (mode GLenum) (first GLint-*) (count GLsizei-*) (primcount GLsizei) -> void)) "Render multiple sets of primitives from array data. MODE Specifies what kind of primitives to render. Symbolic constants `GL_POINTS', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_LINES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_TRIANGLES', `GL_QUAD_STRIP', `GL_QUADS', and `GL_POLYGON' are accepted. FIRST Points to an array of starting indices in the enabled arrays. COUNT Points to an array of the number of indices to be rendered. PRIMCOUNT Specifies the size of the first and count `glMultiDrawArrays' specifies multiple sets of geometric primitives with very few subroutine calls. Instead of calling a GL procedure to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and colors and use them to construct a sequence of primitives with a single call to `glMultiDrawArrays'. `glMultiDrawArrays' behaves identically to `glDrawArrays' except that PRIMCOUNT separate ranges of elements are specified instead. When `glMultiDrawArrays' is called, it uses COUNT sequential elements from each enabled array to construct a sequence of geometric primitives, beginning with element FIRST. MODE specifies what kind of primitives are constructed, and how the array elements construct those primitives. If `GL_VERTEX_ARRAY' is not enabled, no geometric primitives are generated. Vertex attributes that are modified by `glMultiDrawArrays' have an unspecified value after `glMultiDrawArrays' returns. For example, if `GL_COLOR_ARRAY' is enabled, the value of the current color is undefined after `glMultiDrawArrays' executes. Attributes that aren't modified remain well defined. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_VALUE' is generated if PRIMCOUNT is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if `glMultiDrawArrays' is executed between the execution of `glBegin' and the corresponding `glEnd'.") (define-gl-procedures ((glMultiDrawElements (mode GLenum) (count const-GLsizei-*) (type GLenum) (indices const-GLvoid-**) (primcount GLsizei) -> void)) "Render multiple sets of primitives by specifying indices of array data elements. MODE Specifies what kind of primitives to render. Symbolic constants `GL_POINTS', `GL_LINE_STRIP', `GL_LINE_LOOP', `GL_LINES', `GL_TRIANGLE_STRIP', `GL_TRIANGLE_FAN', `GL_TRIANGLES', `GL_QUAD_STRIP', `GL_QUADS', and `GL_POLYGON' are accepted. COUNT Points to an array of the elements counts. TYPE Specifies the type of the values in INDICES. Must be one of `GL_UNSIGNED_BYTE', `GL_UNSIGNED_SHORT', or `GL_UNSIGNED_INT'. INDICES Specifies a pointer to the location where the indices are stored. PRIMCOUNT Specifies the size of the COUNT array. `glMultiDrawElements' specifies multiple sets of geometric primitives with very few subroutine calls. Instead of calling a GL function to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and so on, and use them to construct a sequence of primitives with a single call to `glMultiDrawElements'. `glMultiDrawElements' is identical in operation to `glDrawElements' except that PRIMCOUNT separate lists of elements are specified. Vertex attributes that are modified by `glMultiDrawElements' have an unspecified value after `glMultiDrawElements' returns. For example, if `GL_COLOR_ARRAY' is enabled, the value of the current color is undefined after `glMultiDrawElements' executes. Attributes that aren't modified maintain their previous values. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_VALUE' is generated if PRIMCOUNT is negative. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to an enabled array or the element array and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if `glMultiDrawElements' is executed between the execution of `glBegin' and the corresponding `glEnd'.") (define-gl-procedures ((glMultiTexCoord1i (target GLenum) (s GLint) -> void) (glMultiTexCoord1f (target GLenum) (s GLfloat) -> void) (glMultiTexCoord2i (target GLenum) (s GLint) (t GLint) -> void) (glMultiTexCoord2f (target GLenum) (s GLfloat) (t GLfloat) -> void) (glMultiTexCoord3i (target GLenum) (s GLint) (t GLint) (r GLint) -> void) (glMultiTexCoord3f (target GLenum) (s GLfloat) (t GLfloat) (r GLfloat) -> void) (glMultiTexCoord4i (target GLenum) (s GLint) (t GLint) (r GLint) (q GLint) -> void) (glMultiTexCoord4f (target GLenum) (s GLfloat) (t GLfloat) (r GLfloat) (q GLfloat) -> void)) "Set the current texture coordinates. TARGET Specifies the texture unit whose coordinates should be modified. The number of texture units is implementation dependent, but must be at least two. Symbolic constant must be one of `GL_TEXTURE' I , where i ranges from 0 to `GL_MAX_TEXTURE_COORDS' - 1, which is an implementation-dependent value. S T R Q Specify S, T, R, and Q texture coordinates for TARGET texture unit. Not all parameters are present in all forms of the command. `glMultiTexCoord' specifies texture coordinates in one, two, three, or four dimensions. `glMultiTexCoord1' sets the current texture coordinates to (S,001) ; a call to `glMultiTexCoord2' sets them to (S,T01) . Similarly, `glMultiTexCoord3' specifies the texture coordinates as (S,TR1) , and `glMultiTexCoord4' defines all four components explicitly as (S,TRQ) . The current texture coordinates are part of the data that is associated with each vertex and with the current raster position. Initially, the values for (S,TRQ) are (0,001) .") (define-gl-procedures ((glMultMatrixf (m const-GLfloat-*) -> void)) "Multiply the current matrix with the specified matrix. M Points to 16 consecutive values that are used as the elements of a 4×4 column-major matrix. `glMultMatrix' multiplies the current matrix with the one specified using M, and replaces the current matrix with the product. The current matrix is determined by the current matrix mode (see `glMatrixMode'). It is either the projection matrix, modelview matrix, or the texture matrix. `GL_INVALID_OPERATION' is generated if `glMultMatrix' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glMultTransposeMatrixf (m const-GLfloat-*) -> void)) "Multiply the current matrix with the specified row-major ordered matrix. M Points to 16 consecutive values that are used as the elements of a 4×4 row-major matrix. `glMultTransposeMatrix' multiplies the current matrix with the one specified using M, and replaces the current matrix with the product. The current matrix is determined by the current matrix mode (see `glMatrixMode'). It is either the projection matrix, modelview matrix, or the texture matrix. `GL_INVALID_OPERATION' is generated if `glMultTransposeMatrix' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glNewList (list GLuint) (mode GLenum) -> void) (glEndList -> void)) "Create or replace a display list. LIST Specifies the display-list name. MODE Specifies the compilation mode, which can be `GL_COMPILE' or `GL_COMPILE_AND_EXECUTE'. Display lists are groups of GL commands that have been stored for subsequent execution. Display lists are created with `glNewList'. All subsequent commands are placed in the display list, in the order issued, until `glEndList' is called. `glNewList' has two arguments. The first argument, LIST, is a positive integer that becomes the unique name for the display list. Names can be created and reserved with `glGenLists' and tested for uniqueness with `glIsList'. The second argument, MODE, is a symbolic constant that can assume one of two values: `GL_COMPILE' Commands are merely compiled. `GL_COMPILE_AND_EXECUTE' Commands are executed as they are compiled into the display list. Certain commands are not compiled into the display list but are executed immediately, regardless of the display-list mode. These commands are `glAreTexturesResident', `glColorPointer', `glDeleteLists', `glDeleteTextures', `glDisableClientState', `glEdgeFlagPointer', `glEnableClientState', `glFeedbackBuffer', `glFinish', `glFlush', `glGenLists', `glGenTextures', `glIndexPointer', `glInterleavedArrays', `glIsEnabled', `glIsList', `glIsTexture', `glNormalPointer', `glPopClientAttrib', `glPixelStore', `glPushClientAttrib', `glReadPixels', `glRenderMode', `glSelectBuffer', `glTexCoordPointer', `glVertexPointer', and all of the `glGet' commands. Similarly, `glTexImage1D', `glTexImage2D', and `glTexImage3D' are executed immediately and not compiled into the display list when their first argument is `GL_PROXY_TEXTURE_1D', `GL_PROXY_TEXTURE_1D', or `GL_PROXY_TEXTURE_3D', respectively. When the `ARB_imaging' extension is supported, `glHistogram' executes immediately when its argument is `GL_PROXY_HISTOGRAM'. Similarly, `glColorTable' executes immediately when its first argument is `GL_PROXY_COLOR_TABLE', `GL_PROXY_POST_CONVOLUTION_COLOR_TABLE', or `GL_PROXY_POST_COLOR_MATRIX_COLOR_TABLE'. For OpenGL versions 1.3 and greater, or when the `ARB_multitexture' extension is supported, `glClientActiveTexture' is not compiled into display lists, but executed immediately. When `glEndList' is encountered, the display-list definition is completed by associating the list with the unique name LIST (specified in the `glNewList' command). If a display list with name LIST already exists, it is replaced only when `glEndList' is called. `GL_INVALID_VALUE' is generated if LIST is 0. `GL_INVALID_ENUM' is generated if MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glEndList' is called without a preceding `glNewList', or if `glNewList' is called while a display list is being defined. `GL_INVALID_OPERATION' is generated if `glNewList' or `glEndList' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'. `GL_OUT_OF_MEMORY' is generated if there is insufficient memory to compile the display list. If the GL version is 1.1 or greater, no change is made to the previous contents of the display list, if any, and no other change is made to the GL state. (It is as if no attempt had been made to create the new display list.)") (define-gl-procedures ((glNormalPointer (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of normals. TYPE Specifies the data type of each coordinate in the array. Symbolic constants `GL_BYTE', `GL_SHORT', `GL_INT', `GL_FLOAT', and `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive normals. If STRIDE is 0, the normals are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first coordinate of the first normal in the array. The initial value is 0. `glNormalPointer' specifies the location and data format of an array of normals to use when rendering. TYPE specifies the data type of each normal coordinate, and STRIDE specifies the byte stride from one normal to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see `glInterleavedArrays'.) If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a normal array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as normal vertex array client-side state (`GL_NORMAL_ARRAY_BUFFER_BINDING'). When a normal array is specified, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the normal array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_NORMAL_ARRAY'. If enabled, the normal array is used when `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', `glDrawRangeElements', or `glArrayElement' is called. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glNormal3f (nx GLfloat) (ny GLfloat) (nz GLfloat) -> void) (glNormal3i (nx GLint) (ny GLint) (nz GLint) -> void)) "Set the current normal vector. NX NY NZ Specify the X , Y , and Z coordinates of the new current normal. The initial value of the current normal is the unit vector, (0, 0, 1). The current normal is set to the given coordinates whenever `glNormal' is issued. Byte, short, or integer arguments are converted to floating-point format with a linear mapping that maps the most positive representable integer value to 1.0 and the most negative representable integer value to -1.0 . Normals specified with `glNormal' need not have unit length. If `GL_NORMALIZE' is enabled, then normals of any length specified with `glNormal' are normalized after transformation. If `GL_RESCALE_NORMAL' is enabled, normals are scaled by a scaling factor derived from the modelview matrix. `GL_RESCALE_NORMAL' requires that the originally specified normals were of unit length, and that the modelview matrix contain only uniform scales for proper results. To enable and disable normalization, call `glEnable' and `glDisable' with either `GL_NORMALIZE' or `GL_RESCALE_NORMAL'. Normalization is initially disabled.") (define-gl-procedures ((glOrtho (left GLdouble) (right GLdouble) (bottom GLdouble) (top GLdouble) (nearVal GLdouble) (farVal GLdouble) -> void)) "Multiply the current matrix with an orthographic matrix. LEFT RIGHT Specify the coordinates for the left and right vertical clipping planes. BOTTOM TOP Specify the coordinates for the bottom and top horizontal clipping planes. NEARVAL FARVAL Specify the distances to the nearer and farther depth clipping planes. These values are negative if the plane is to be behind the viewer. `glOrtho' describes a transformation that produces a parallel projection. The current matrix (see `glMatrixMode') is multiplied by this matrix and the result replaces the current matrix, as if `glMultMatrix' were called with the following matrix as its argument: ((2/RIGHT-LEFT,, 0 0 T_X,), (0 2/TOP-BOTTOM,, 0 T_Y,), (0 0 -2/FARVAL-NEARVAL,, T_Z,), (0 0 0 1),) where T_X=-RIGHT+LEFT,/RIGHT-LEFT,, T_Y=-TOP+BOTTOM,/TOP-BOTTOM,, T_Z=-FARVAL+NEARVAL,/FARVAL-NEARVAL,, Typically, the matrix mode is `GL_PROJECTION', and (LEFT,BOTTOM-NEARVAL) and (RIGHT,TOP-NEARVAL) specify the points on the near clipping plane that are mapped to the lower left and upper right corners of the window, respectively, assuming that the eye is located at (0, 0, 0). -FARVAL specifies the location of the far clipping plane. Both NEARVAL and FARVAL can be either positive or negative. Use `glPushMatrix' and `glPopMatrix' to save and restore the current matrix stack. `GL_INVALID_VALUE' is generated if LEFT = RIGHT, or BOTTOM = TOP, or NEAR = FAR. `GL_INVALID_OPERATION' is generated if `glOrtho' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPassThrough (token GLfloat) -> void)) "Place a marker in the feedback buffer. TOKEN Specifies a marker value to be placed in the feedback buffer following a `GL_PASS_THROUGH_TOKEN'. Feedback is a GL render mode. The mode is selected by calling `glRenderMode' with `GL_FEEDBACK'. When the GL is in feedback mode, no pixels are produced by rasterization. Instead, information about primitives that would have been rasterized is fed back to the application using the GL. See the `glFeedbackBuffer' reference page for a description of the feedback buffer and the values in it. `glPassThrough' inserts a user-defined marker in the feedback buffer when it is executed in feedback mode. TOKEN is returned as if it were a primitive; it is indicated with its own unique identifying value: `GL_PASS_THROUGH_TOKEN'. The order of `glPassThrough' commands with respect to the specification of graphics primitives is maintained. `GL_INVALID_OPERATION' is generated if `glPassThrough' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPixelMapfv (map GLenum) (mapsize GLsizei) (values const-GLfloat-*) -> void) (glPixelMapuiv (map GLenum) (mapsize GLsizei) (values const-GLuint-*) -> void)) "Set up pixel transfer maps. MAP Specifies a symbolic map name. Must be one of the following: `GL_PIXEL_MAP_I_TO_I', `GL_PIXEL_MAP_S_TO_S', `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', `GL_PIXEL_MAP_I_TO_A', `GL_PIXEL_MAP_R_TO_R', `GL_PIXEL_MAP_G_TO_G', `GL_PIXEL_MAP_B_TO_B', or `GL_PIXEL_MAP_A_TO_A'. MAPSIZE Specifies the size of the map being defined. VALUES Specifies an array of MAPSIZE values. `glPixelMap' sets up translation tables, or MAPS, used by `glCopyPixels', `glCopyTexImage1D', `glCopyTexImage2D', `glCopyTexSubImage1D', `glCopyTexSubImage2D', `glCopyTexSubImage3D', `glDrawPixels', `glReadPixels', `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', and `glTexSubImage3D'. Additionally, if the `ARB_imaging' subset is supported, the routines `glColorTable', `glColorSubTable', `glConvolutionFilter1D', `glConvolutionFilter2D', `glHistogram', `glMinmax', and `glSeparableFilter2D'. Use of these maps is described completely in the `glPixelTransfer' reference page, and partly in the reference pages for the pixel and texture image commands. Only the specification of the maps is described in this reference page. MAP is a symbolic map name, indicating one of ten maps to set. MAPSIZE specifies the number of entries in the map, and VALUES is a pointer to an array of MAPSIZE map values. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a pixel transfer map is specified, VALUES is treated as a byte offset into the buffer object's data store. The ten maps are as follows: `GL_PIXEL_MAP_I_TO_I' Maps color indices to color indices. `GL_PIXEL_MAP_S_TO_S' Maps stencil indices to stencil indices. `GL_PIXEL_MAP_I_TO_R' Maps color indices to red components. `GL_PIXEL_MAP_I_TO_G' Maps color indices to green components. `GL_PIXEL_MAP_I_TO_B' Maps color indices to blue components. `GL_PIXEL_MAP_I_TO_A' Maps color indices to alpha components. `GL_PIXEL_MAP_R_TO_R' Maps red components to red components. `GL_PIXEL_MAP_G_TO_G' Maps green components to green components. `GL_PIXEL_MAP_B_TO_B' Maps blue components to blue components. `GL_PIXEL_MAP_A_TO_A' Maps alpha components to alpha components. The entries in a map can be specified as single-precision floating-point numbers, unsigned short integers, or unsigned int integers. Maps that store color component values (all but `GL_PIXEL_MAP_I_TO_I' and `GL_PIXEL_MAP_S_TO_S') retain their values in floating-point format, with unspecified mantissa and exponent sizes. Floating-point values specified by `glPixelMapfv' are converted directly to the internal floating-point format of these maps, then clamped to the range [0,1]. Unsigned integer values specified by `glPixelMapusv' and `glPixelMapuiv' are converted linearly such that the largest representable integer maps to 1.0, and 0 maps to 0.0. Maps that store indices, `GL_PIXEL_MAP_I_TO_I' and `GL_PIXEL_MAP_S_TO_S', retain their values in fixed-point format, with an unspecified number of bits to the right of the binary point. Floating-point values specified by `glPixelMapfv' are converted directly to the internal fixed-point format of these maps. Unsigned integer values specified by `glPixelMapusv' and `glPixelMapuiv' specify integer values, with all 0's to the right of the binary point. The following table shows the initial sizes and values for each of the maps. Maps that are indexed by either color or stencil indices must have MAPSIZE = 2^N for some N or the results are undefined. The maximum allowable size for each map depends on the implementation and can be determined by calling `glGet' with argument `GL_MAX_PIXEL_MAP_TABLE'. The single maximum applies to all maps; it is at least 32. *MAP* *Lookup Index*, *Lookup Value*, *Initial Size*, *Initial Value* `GL_PIXEL_MAP_I_TO_I' color index , color index , 1 , 0 `GL_PIXEL_MAP_S_TO_S' stencil index , stencil index , 1 , 0 `GL_PIXEL_MAP_I_TO_R' color index , R , 1 , 0 `GL_PIXEL_MAP_I_TO_G' color index , G , 1 , 0 `GL_PIXEL_MAP_I_TO_B' color index , B , 1 , 0 `GL_PIXEL_MAP_I_TO_A' color index , A , 1 , 0 `GL_PIXEL_MAP_R_TO_R' R , R , 1 , 0 `GL_PIXEL_MAP_G_TO_G' G , G , 1 , 0 `GL_PIXEL_MAP_B_TO_B' B , B , 1 , 0 `GL_PIXEL_MAP_A_TO_A' A , A , 1 , 0 `GL_INVALID_ENUM' is generated if MAP is not an accepted value. `GL_INVALID_VALUE' is generated if MAPSIZE is less than one or larger than `GL_MAX_PIXEL_MAP_TABLE'. `GL_INVALID_VALUE' is generated if MAP is `GL_PIXEL_MAP_I_TO_I', `GL_PIXEL_MAP_S_TO_S', `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', or `GL_PIXEL_MAP_I_TO_A', and MAPSIZE is not a power of two. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated by `glPixelMapfv' if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and VALUES is not evenly divisible into the number of bytes needed to store in memory a GLfloat datum. `GL_INVALID_OPERATION' is generated by `glPixelMapuiv' if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and VALUES is not evenly divisible into the number of bytes needed to store in memory a GLuint datum. `GL_INVALID_OPERATION' is generated by `glPixelMapusv' if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and VALUES is not evenly divisible into the number of bytes needed to store in memory a GLushort datum. `GL_INVALID_OPERATION' is generated if `glPixelMap' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPixelStoref (pname GLenum) (param GLfloat) -> void) (glPixelStorei (pname GLenum) (param GLint) -> void)) "Set pixel storage modes. PNAME Specifies the symbolic name of the parameter to be set. Six values affect the packing of pixel data into memory: `GL_PACK_SWAP_BYTES', `GL_PACK_LSB_FIRST', `GL_PACK_ROW_LENGTH', `GL_PACK_IMAGE_HEIGHT', `GL_PACK_SKIP_PIXELS', `GL_PACK_SKIP_ROWS', `GL_PACK_SKIP_IMAGES', and `GL_PACK_ALIGNMENT'. Six more affect the unpacking of pixel data FROM memory: `GL_UNPACK_SWAP_BYTES', `GL_UNPACK_LSB_FIRST', `GL_UNPACK_ROW_LENGTH', `GL_UNPACK_IMAGE_HEIGHT', `GL_UNPACK_SKIP_PIXELS', `GL_UNPACK_SKIP_ROWS', `GL_UNPACK_SKIP_IMAGES', and `GL_UNPACK_ALIGNMENT'. PARAM Specifies the value that PNAME is set to. `glPixelStore' sets pixel storage modes that affect the operation of subsequent `glDrawPixels' and `glReadPixels' as well as the unpacking of polygon stipple patterns (see `glPolygonStipple'), bitmaps (see `glBitmap'), texture patterns (see `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', `glTexSubImage3D'). Additionally, if the `ARB_imaging' extension is supported, pixel storage modes affect convolution filters (see `glConvolutionFilter1D', `glConvolutionFilter2D', and `glSeparableFilter2D', color table (see `glColorTable', and `glColorSubTable', and unpacking histogram (See `glHistogram'), and minmax (See `glMinmax') data. PNAME is a symbolic constant indicating the parameter to be set, and PARAM is the new value. Six of the twelve storage parameters affect how pixel data is returned to client memory. They are as follows: `GL_PACK_SWAP_BYTES' If true, byte ordering for multibyte color components, depth components, color indices, or stencil indices is reversed. That is, if a four-byte component consists of bytes B_0 , B_1 , B_2 , B_3 , it is stored in memory as B_3 , B_2 , B_1 , B_0 if `GL_PACK_SWAP_BYTES' is true. `GL_PACK_SWAP_BYTES' has no effect on the memory order of components within a pixel, only on the order of bytes within components or indices. For example, the three components of a `GL_RGB' format pixel are always stored with red first, green second, and blue third, regardless of the value of `GL_PACK_SWAP_BYTES'. `GL_PACK_LSB_FIRST' If true, bits are ordered within a byte from least significant to most significant; otherwise, the first bit in each byte is the most significant one. This parameter is significant for bitmap data only. `GL_PACK_ROW_LENGTH' If greater than 0, `GL_PACK_ROW_LENGTH' defines the number of pixels in a row. If the first pixel of a row is placed at location P in memory, then the location of the first pixel of the next row is obtained by skipping K={(N\u2062L), (A/S,\u2062⌈S\u2062N\u2062L,/A,⌉)\u2062(S>=A), (S=A), (S=A), (S=A), (S void) (glPixelTransferi (pname GLenum) (param GLint) -> void)) "Set pixel transfer modes. PNAME Specifies the symbolic name of the pixel transfer parameter to be set. Must be one of the following: `GL_MAP_COLOR', `GL_MAP_STENCIL', `GL_INDEX_SHIFT', `GL_INDEX_OFFSET', `GL_RED_SCALE', `GL_RED_BIAS', `GL_GREEN_SCALE', `GL_GREEN_BIAS', `GL_BLUE_SCALE', `GL_BLUE_BIAS', `GL_ALPHA_SCALE', `GL_ALPHA_BIAS', `GL_DEPTH_SCALE', or `GL_DEPTH_BIAS'. Additionally, if the `ARB_imaging' extension is supported, the following symbolic names are accepted: `GL_POST_COLOR_MATRIX_RED_SCALE', `GL_POST_COLOR_MATRIX_GREEN_SCALE', `GL_POST_COLOR_MATRIX_BLUE_SCALE', `GL_POST_COLOR_MATRIX_ALPHA_SCALE', `GL_POST_COLOR_MATRIX_RED_BIAS', `GL_POST_COLOR_MATRIX_GREEN_BIAS', `GL_POST_COLOR_MATRIX_BLUE_BIAS', `GL_POST_COLOR_MATRIX_ALPHA_BIAS', `GL_POST_CONVOLUTION_RED_SCALE', `GL_POST_CONVOLUTION_GREEN_SCALE', `GL_POST_CONVOLUTION_BLUE_SCALE', `GL_POST_CONVOLUTION_ALPHA_SCALE', `GL_POST_CONVOLUTION_RED_BIAS', `GL_POST_CONVOLUTION_GREEN_BIAS', `GL_POST_CONVOLUTION_BLUE_BIAS', and `GL_POST_CONVOLUTION_ALPHA_BIAS'. PARAM Specifies the value that PNAME is set to. `glPixelTransfer' sets pixel transfer modes that affect the operation of subsequent `glCopyPixels', `glCopyTexImage1D', `glCopyTexImage2D', `glCopyTexSubImage1D', `glCopyTexSubImage2D', `glCopyTexSubImage3D', `glDrawPixels', `glReadPixels', `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', and `glTexSubImage3D' commands. Additionally, if the `ARB_imaging' subset is supported, the routines `glColorTable', `glColorSubTable', `glConvolutionFilter1D', `glConvolutionFilter2D', `glHistogram', `glMinmax', and `glSeparableFilter2D' are also affected. The algorithms that are specified by pixel transfer modes operate on pixels after they are read from the frame buffer (`glCopyPixels'`glCopyTexImage1D', `glCopyTexImage2D', `glCopyTexSubImage1D', `glCopyTexSubImage2D', `glCopyTexSubImage3D', and `glReadPixels'), or unpacked from client memory (`glDrawPixels', `glTexImage1D', `glTexImage2D', `glTexImage3D', `glTexSubImage1D', `glTexSubImage2D', and `glTexSubImage3D'). Pixel transfer operations happen in the same order, and in the same manner, regardless of the command that resulted in the pixel operation. Pixel storage modes (see `glPixelStore') control the unpacking of pixels being read from client memory and the packing of pixels being written back into client memory. Pixel transfer operations handle four fundamental pixel types: COLOR, COLOR INDEX, DEPTH, and STENCIL. COLOR pixels consist of four floating-point values with unspecified mantissa and exponent sizes, scaled such that 0 represents zero intensity and 1 represents full intensity. COLOR INDICES comprise a single fixed-point value, with unspecified precision to the right of the binary point. DEPTH pixels comprise a single floating-point value, with unspecified mantissa and exponent sizes, scaled such that 0.0 represents the minimum depth buffer value, and 1.0 represents the maximum depth buffer value. Finally, STENCIL pixels comprise a single fixed-point value, with unspecified precision to the right of the binary point. The pixel transfer operations performed on the four basic pixel types are as follows: COLOR Each of the four color components is multiplied by a scale factor, then added to a bias factor. That is, the red component is multiplied by `GL_RED_SCALE', then added to `GL_RED_BIAS'; the green component is multiplied by `GL_GREEN_SCALE', then added to `GL_GREEN_BIAS'; the blue component is multiplied by `GL_BLUE_SCALE', then added to `GL_BLUE_BIAS'; and the alpha component is multiplied by `GL_ALPHA_SCALE', then added to `GL_ALPHA_BIAS'. After all four color components are scaled and biased, each is clamped to the range [0,1] . All color, scale, and bias values are specified with `glPixelTransfer'. If `GL_MAP_COLOR' is true, each color component is scaled by the size of the corresponding color-to-color map, then replaced by the contents of that map indexed by the scaled component. That is, the red component is scaled by `GL_PIXEL_MAP_R_TO_R_SIZE', then replaced by the contents of `GL_PIXEL_MAP_R_TO_R' indexed by itself. The green component is scaled by `GL_PIXEL_MAP_G_TO_G_SIZE', then replaced by the contents of `GL_PIXEL_MAP_G_TO_G' indexed by itself. The blue component is scaled by `GL_PIXEL_MAP_B_TO_B_SIZE', then replaced by the contents of `GL_PIXEL_MAP_B_TO_B' indexed by itself. And the alpha component is scaled by `GL_PIXEL_MAP_A_TO_A_SIZE', then replaced by the contents of `GL_PIXEL_MAP_A_TO_A' indexed by itself. All components taken from the maps are then clamped to the range [0,1] . `GL_MAP_COLOR' is specified with `glPixelTransfer'. The contents of the various maps are specified with `glPixelMap'. If the `ARB_imaging' extension is supported, each of the four color components may be scaled and biased after transformation by the color matrix. That is, the red component is multiplied by `GL_POST_COLOR_MATRIX_RED_SCALE', then added to `GL_POST_COLOR_MATRIX_RED_BIAS'; the green component is multiplied by `GL_POST_COLOR_MATRIX_GREEN_SCALE', then added to `GL_POST_COLOR_MATRIX_GREEN_BIAS'; the blue component is multiplied by `GL_POST_COLOR_MATRIX_BLUE_SCALE', then added to `GL_POST_COLOR_MATRIX_BLUE_BIAS'; and the alpha component is multiplied by `GL_POST_COLOR_MATRIX_ALPHA_SCALE', then added to `GL_POST_COLOR_MATRIX_ALPHA_BIAS'. After all four color components are scaled and biased, each is clamped to the range [0,1] . Similarly, if the `ARB_imaging' extension is supported, each of the four color components may be scaled and biased after processing by the enabled convolution filter. That is, the red component is multiplied by `GL_POST_CONVOLUTION_RED_SCALE', then added to `GL_POST_CONVOLUTION_RED_BIAS'; the green component is multiplied by `GL_POST_CONVOLUTION_GREEN_SCALE', then added to `GL_POST_CONVOLUTION_GREEN_BIAS'; the blue component is multiplied by `GL_POST_CONVOLUTION_BLUE_SCALE', then added to `GL_POST_CONVOLUTION_BLUE_BIAS'; and the alpha component is multiplied by `GL_POST_CONVOLUTION_ALPHA_SCALE', then added to `GL_POST_CONVOLUTION_ALPHA_BIAS'. After all four color components are scaled and biased, each is clamped to the range [0,1] . COLOR INDEX Each color index is shifted left by `GL_INDEX_SHIFT' bits; any bits beyond the number of fraction bits carried by the fixed-point index are filled with zeros. If `GL_INDEX_SHIFT' is negative, the shift is to the right, again zero filled. Then `GL_INDEX_OFFSET' is added to the index. `GL_INDEX_SHIFT' and `GL_INDEX_OFFSET' are specified with `glPixelTransfer'. From this point, operation diverges depending on the required format of the resulting pixels. If the resulting pixels are to be written to a color index buffer, or if they are being read back to client memory in `GL_COLOR_INDEX' format, the pixels continue to be treated as indices. If `GL_MAP_COLOR' is true, each index is masked by 2^N-1 , where N is `GL_PIXEL_MAP_I_TO_I_SIZE', then replaced by the contents of `GL_PIXEL_MAP_I_TO_I' indexed by the masked value. `GL_MAP_COLOR' is specified with `glPixelTransfer'. The contents of the index map is specified with `glPixelMap'. If the resulting pixels are to be written to an RGBA color buffer, or if they are read back to client memory in a format other than `GL_COLOR_INDEX', the pixels are converted from indices to colors by referencing the four maps `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', and `GL_PIXEL_MAP_I_TO_A'. Before being dereferenced, the index is masked by 2^N-1 , where N is `GL_PIXEL_MAP_I_TO_R_SIZE' for the red map, `GL_PIXEL_MAP_I_TO_G_SIZE' for the green map, `GL_PIXEL_MAP_I_TO_B_SIZE' for the blue map, and `GL_PIXEL_MAP_I_TO_A_SIZE' for the alpha map. All components taken from the maps are then clamped to the range [0,1] . The contents of the four maps is specified with `glPixelMap'. DEPTH Each depth value is multiplied by `GL_DEPTH_SCALE', added to `GL_DEPTH_BIAS', then clamped to the range [0,1] . STENCIL Each index is shifted `GL_INDEX_SHIFT' bits just as a color index is, then added to `GL_INDEX_OFFSET'. If `GL_MAP_STENCIL' is true, each index is masked by 2^N-1 , where N is `GL_PIXEL_MAP_S_TO_S_SIZE', then replaced by the contents of `GL_PIXEL_MAP_S_TO_S' indexed by the masked value. The following table gives the type, initial value, and range of valid values for each of the pixel transfer parameters that are set with `glPixelTransfer'. *PNAME* *Type*, *Initial Value*, *Valid Range* `GL_MAP_COLOR' boolean , false , true/false `GL_MAP_STENCIL' boolean , false , true/false `GL_INDEX_SHIFT' integer , 0 , (-∞,∞) `GL_INDEX_OFFSET' integer , 0 , (-∞,∞) `GL_RED_SCALE' float , 1 , (-∞,∞) `GL_GREEN_SCALE' float , 1 , (-∞,∞) `GL_BLUE_SCALE' float , 1 , (-∞,∞) `GL_ALPHA_SCALE' float , 1 , (-∞,∞) `GL_DEPTH_SCALE' float , 1 , (-∞,∞) `GL_RED_BIAS' float , 0 , (-∞,∞) `GL_GREEN_BIAS' float , 0 , (-∞,∞) `GL_BLUE_BIAS' float , 0 , (-∞,∞) `GL_ALPHA_BIAS' float , 0 , (-∞,∞) `GL_DEPTH_BIAS' float , 0 , (-∞,∞) `GL_POST_COLOR_MATRIX_RED_SCALE' float , 1 , (-∞,∞) `GL_POST_COLOR_MATRIX_GREEN_SCALE' float , 1 , (-∞,∞) `GL_POST_COLOR_MATRIX_BLUE_SCALE' float , 1 , (-∞,∞) `GL_POST_COLOR_MATRIX_ALPHA_SCALE' float , 1 , (-∞,∞) `GL_POST_COLOR_MATRIX_RED_BIAS' float , 0 , (-∞,∞) `GL_POST_COLOR_MATRIX_GREEN_BIAS' float , 0 , (-∞,∞) `GL_POST_COLOR_MATRIX_BLUE_BIAS' float , 0 , (-∞,∞) `GL_POST_COLOR_MATRIX_ALPHA_BIAS' float , 0 , (-∞,∞) `GL_POST_CONVOLUTION_RED_SCALE' float , 1 , (-∞,∞) `GL_POST_CONVOLUTION_GREEN_SCALE' float , 1 , (-∞,∞) `GL_POST_CONVOLUTION_BLUE_SCALE' float , 1 , (-∞,∞) `GL_POST_CONVOLUTION_ALPHA_SCALE' float , 1 , (-∞,∞) `GL_POST_CONVOLUTION_RED_BIAS' float , 0 , (-∞,∞) `GL_POST_CONVOLUTION_GREEN_BIAS' float , 0 , (-∞,∞) `GL_POST_CONVOLUTION_BLUE_BIAS' float , 0 , (-∞,∞) `GL_POST_CONVOLUTION_ALPHA_BIAS' float , 0 , (-∞,∞) `glPixelTransferf' can be used to set any pixel transfer parameter. If the parameter type is boolean, 0 implies false and any other value implies true. If PNAME is an integer parameter, PARAM is rounded to the nearest integer. Likewise, `glPixelTransferi' can be used to set any of the pixel transfer parameters. Boolean parameters are set to false if PARAM is 0 and to true otherwise. PARAM is converted to floating point before being assigned to real-valued parameters. `GL_INVALID_ENUM' is generated if PNAME is not an accepted value. `GL_INVALID_OPERATION' is generated if `glPixelTransfer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPixelZoom (xfactor GLfloat) (yfactor GLfloat) -> void)) "Specify the pixel zoom factors. XFACTOR YFACTOR Specify the X and Y zoom factors for pixel write operations. `glPixelZoom' specifies values for the X and Y zoom factors. During the execution of `glDrawPixels' or `glCopyPixels', if (XR , YR ) is the current raster position, and a given element is in the M th row and N th column of the pixel rectangle, then pixels whose centers are in the rectangle with corners at (XR+N·XFACTOR , YR+M·YFACTOR ) (XR+(N+1,)·XFACTOR , YR+(M+1,)·YFACTOR ) are candidates for replacement. Any pixel whose center lies on the bottom or left edge of this rectangular region is also modified. Pixel zoom factors are not limited to positive values. Negative zoom factors reflect the resulting image about the current raster position. `GL_INVALID_OPERATION' is generated if `glPixelZoom' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPointParameterf (pname GLenum) (param GLfloat) -> void) (glPointParameteri (pname GLenum) (param GLint) -> void)) "Specify point parameters. PNAME Specifies a single-valued point parameter. `GL_POINT_SIZE_MIN', `GL_POINT_SIZE_MAX', `GL_POINT_FADE_THRESHOLD_SIZE', and `GL_POINT_SPRITE_COORD_ORIGIN' are accepted. PARAM Specifies the value that PNAME will be set to. The following values are accepted for PNAME: `GL_POINT_SIZE_MIN' PARAMS is a single floating-point value that specifies the minimum point size. The default value is 0.0. `GL_POINT_SIZE_MAX' PARAMS is a single floating-point value that specifies the maximum point size. The default value is 1.0. `GL_POINT_FADE_THRESHOLD_SIZE' PARAMS is a single floating-point value that specifies the threshold value to which point sizes are clamped if they exceed the specified value. The default value is 1.0. `GL_POINT_DISTANCE_ATTENUATION' PARAMS is an array of three floating-point values that specify the coefficients used for scaling the computed point size. The default values are (1,00) . `GL_POINT_SPRITE_COORD_ORIGIN' PARAMS is a single enum specifying the point sprite texture coordinate origin, either `GL_LOWER_LEFT' or `GL_UPPER_LEFT'. The default value is `GL_UPPER_LEFT'. `GL_INVALID_VALUE' is generated If the value specified for `GL_POINT_SIZE_MIN', `GL_POINT_SIZE_MAX', or `GL_POINT_FADE_THRESHOLD_SIZE' is less than zero. `GL_INVALID_ENUM' is generated If the value specified for `GL_POINT_SPRITE_COORD_ORIGIN' is not `GL_LOWER_LEFT' or `GL_UPPER_LEFT'. If the value for `GL_POINT_SIZE_MIN' is greater than `GL_POINT_SIZE_MAX', the point size after clamping is undefined, but no error is generated.") (define-gl-procedures ((glPointSize (size GLfloat) -> void)) "Specify the diameter of rasterized points. SIZE Specifies the diameter of rasterized points. The initial value is 1. `glPointSize' specifies the rasterized diameter of both aliased and antialiased points. Using a point size other than 1 has different effects, depending on whether point antialiasing is enabled. To enable and disable point antialiasing, call `glEnable' and `glDisable' with argument `GL_POINT_SMOOTH'. Point antialiasing is initially disabled. The specified point size is multiplied with a distance attenuation factor and clamped to the specified point size range, and further clamped to the implementation-dependent point size range to produce the derived point size using POINTSIZE=CLAMP\u2062(SIZE×√(1/A+B×D+C×D^2,,,),,) where D is the eye-coordinate distance from the eye to the vertex, and A , B , and C are the distance attenuation coefficients (see `glPointParameter'). If multisampling is disabled, the computed point size is used as the point's width. If multisampling is enabled, the point may be faded by modifying the point alpha value (see `glSampleCoverage') instead of allowing the point width to go below a given threshold (see `glPointParameter'). In this case, the width is further modified in the following manner: POINTWIDTH={(POINTSIZE), (THRESHOLD)\u2062(POINTSIZE>=THRESHOLD), (OTHERWISE), The point alpha value is modified by computing: POINTALPHA={(1), ((POINTSIZE/THRESHOLD,)^2)\u2062(POINTSIZE>=THRESHOLD), (OTHERWISE), If point antialiasing is disabled, the actual size is determined by rounding the supplied size to the nearest integer. (If the rounding results in the value 0, it is as if the point size were 1.) If the rounded size is odd, then the center point (X , Y ) of the pixel fragment that represents the point is computed as (⌊X_W,⌋+.5,⌊Y_W,⌋+.5) where W subscripts indicate window coordinates. All pixels that lie within the square grid of the rounded size centered at (X , Y ) make up the fragment. If the size is even, the center point is (⌊X_W+.5,⌋,⌊Y_W+.5,⌋) and the rasterized fragment's centers are the half-integer window coordinates within the square of the rounded size centered at (X,Y) . All pixel fragments produced in rasterizing a nonantialiased point are assigned the same associated data, that of the vertex corresponding to the point. If antialiasing is enabled, then point rasterization produces a fragment for each pixel square that intersects the region lying within the circle having diameter equal to the current point size and centered at the point's (X_W,Y_W) . The coverage value for each fragment is the window coordinate area of the intersection of the circular region with the corresponding pixel square. This value is saved and used in the final rasterization step. The data associated with each fragment is the data associated with the point being rasterized. Not all sizes are supported when point antialiasing is enabled. If an unsupported size is requested, the nearest supported size is used. Only size 1 is guaranteed to be supported; others depend on the implementation. To query the range of supported sizes and the size difference between supported sizes within the range, call `glGet' with arguments `GL_SMOOTH_POINT_SIZE_RANGE' and `GL_SMOOTH_POINT_SIZE_GRANULARITY'. For aliased points, query the supported ranges and granularity with `glGet' with arguments `GL_ALIASED_POINT_SIZE_RANGE'. `GL_INVALID_VALUE' is generated if SIZE is less than or equal to 0. `GL_INVALID_OPERATION' is generated if `glPointSize' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPolygonMode (face GLenum) (mode GLenum) -> void)) "Select a polygon rasterization mode. FACE Specifies the polygons that MODE applies to. Must be `GL_FRONT' for front-facing polygons, `GL_BACK' for back-facing polygons, or `GL_FRONT_AND_BACK' for front- and back-facing polygons. MODE Specifies how polygons will be rasterized. Accepted values are `GL_POINT', `GL_LINE', and `GL_FILL'. The initial value is `GL_FILL' for both front- and back-facing polygons. `glPolygonMode' controls the interpretation of polygons for rasterization. FACE describes which polygons MODE applies to: front-facing polygons (`GL_FRONT'), back-facing polygons (`GL_BACK'), or both (`GL_FRONT_AND_BACK'). The polygon mode affects only the final rasterization of polygons. In particular, a polygon's vertices are lit and the polygon is clipped and possibly culled before these modes are applied. Three modes are defined and can be specified in MODE: `GL_POINT' Polygon vertices that are marked as the start of a boundary edge are drawn as points. Point attributes such as `GL_POINT_SIZE' and `GL_POINT_SMOOTH' control the rasterization of the points. Polygon rasterization attributes other than `GL_POLYGON_MODE' have no effect. `GL_LINE' Boundary edges of the polygon are drawn as line segments. They are treated as connected line segments for line stippling; the line stipple counter and pattern are not reset between segments (see `glLineStipple'). Line attributes such as `GL_LINE_WIDTH' and `GL_LINE_SMOOTH' control the rasterization of the lines. Polygon rasterization attributes other than `GL_POLYGON_MODE' have no effect. `GL_FILL' The interior of the polygon is filled. Polygon attributes such as `GL_POLYGON_STIPPLE' and `GL_POLYGON_SMOOTH' control the rasterization of the polygon. `GL_INVALID_ENUM' is generated if either FACE or MODE is not an accepted value. `GL_INVALID_OPERATION' is generated if `glPolygonMode' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPolygonOffset (factor GLfloat) (units GLfloat) -> void)) "Set the scale and units used to calculate depth values. FACTOR Specifies a scale factor that is used to create a variable depth offset for each polygon. The initial value is 0. UNITS Is multiplied by an implementation-specific value to create a constant depth offset. The initial value is 0. When `GL_POLYGON_OFFSET_FILL', `GL_POLYGON_OFFSET_LINE', or `GL_POLYGON_OFFSET_POINT' is enabled, each fragment's DEPTH value will be offset after it is interpolated from the DEPTH values of the appropriate vertices. The value of the offset is FACTOR×DZ+R×UNITS , where DZ is a measurement of the change in depth relative to the screen area of the polygon, and R is the smallest value that is guaranteed to produce a resolvable offset for a given implementation. The offset is added before the depth test is performed and before the value is written into the depth buffer. `glPolygonOffset' is useful for rendering hidden-line images, for applying decals to surfaces, and for rendering solids with highlighted edges. `GL_INVALID_OPERATION' is generated if `glPolygonOffset' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPolygonStipple (pattern const-GLubyte-*) -> void)) "Set the polygon stippling pattern. PATTERN Specifies a pointer to a 32×32 stipple pattern that will be unpacked from memory in the same way that `glDrawPixels' unpacks pixels. Polygon stippling, like line stippling (see `glLineStipple'), masks out certain fragments produced by rasterization, creating a pattern. Stippling is independent of polygon antialiasing. PATTERN is a pointer to a 32×32 stipple pattern that is stored in memory just like the pixel data supplied to a `glDrawPixels' call with height and WIDTH both equal to 32, a pixel format of `GL_COLOR_INDEX', and data type of `GL_BITMAP'. That is, the stipple pattern is represented as a 32×32 array of 1-bit color indices packed in unsigned bytes. `glPixelStore' parameters like `GL_UNPACK_SWAP_BYTES' and `GL_UNPACK_LSB_FIRST' affect the assembling of the bits into a stipple pattern. Pixel transfer operations (shift, offset, pixel map) are not applied to the stipple image, however. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a stipple pattern is specified, PATTERN is treated as a byte offset into the buffer object's data store. To enable and disable polygon stippling, call `glEnable' and `glDisable' with argument `GL_POLYGON_STIPPLE'. Polygon stippling is initially disabled. If it's enabled, a rasterized polygon fragment with window coordinates X_W and Y_W is sent to the next stage of the GL if and only if the (X_W%32 )th bit in the (Y_W%32 )th row of the stipple pattern is 1 (one). When polygon stippling is disabled, it is as if the stipple pattern consists of all 1's. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if `glPolygonStipple' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPrioritizeTextures (n GLsizei) (textures const-GLuint-*) (priorities const-GLclampf-*) -> void)) "Set texture residence priority. N Specifies the number of textures to be prioritized. TEXTURES Specifies an array containing the names of the textures to be prioritized. PRIORITIES Specifies an array containing the texture priorities. A priority given in an element of PRIORITIES applies to the texture named by the corresponding element of TEXTURES. `glPrioritizeTextures' assigns the N texture priorities given in PRIORITIES to the N textures named in TEXTURES. The GL establishes a ``working set'' of textures that are resident in texture memory. These textures may be bound to a texture target much more efficiently than textures that are not resident. By specifying a priority for each texture, `glPrioritizeTextures' allows applications to guide the GL implementation in determining which textures should be resident. The priorities given in PRIORITIES are clamped to the range [0,1] before they are assigned. 0 indicates the lowest priority; textures with priority 0 are least likely to be resident. 1 indicates the highest priority; textures with priority 1 are most likely to be resident. However, textures are not guaranteed to be resident until they are used. `glPrioritizeTextures' silently ignores attempts to prioritize texture 0 or any texture name that does not correspond to an existing texture. `glPrioritizeTextures' does not require that any of the textures named by TEXTURES be bound to a texture target. `glTexParameter' may also be used to set a texture's priority, but only if the texture is currently bound. This is the only way to set the priority of a default texture. `GL_INVALID_VALUE' is generated if N is negative. `GL_INVALID_OPERATION' is generated if `glPrioritizeTextures' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPushAttrib (mask GLbitfield) -> void) (glPopAttrib -> void)) "Push and pop the server attribute stack. MASK Specifies a mask that indicates which attributes to save. Values for MASK are listed below. `glPushAttrib' takes one argument, a mask that indicates which groups of state variables to save on the attribute stack. Symbolic constants are used to set bits in the mask. MASK is typically constructed by specifying the bitwise-or of several of these constants together. The special mask `GL_ALL_ATTRIB_BITS' can be used to save all stackable states. The symbolic mask constants and their associated GL state are as follows (the second column lists which attributes are saved): `GL_ACCUM_BUFFER_BIT' Accumulation buffer clear value `GL_COLOR_BUFFER_BIT' `GL_ALPHA_TEST' enable bit Alpha test function and reference value `GL_BLEND' enable bit Blending source and destination functions Constant blend color Blending equation `GL_DITHER' enable bit `GL_DRAW_BUFFER' setting `GL_COLOR_LOGIC_OP' enable bit `GL_INDEX_LOGIC_OP' enable bit Logic op function Color mode and index mode clear values Color mode and index mode writemasks `GL_CURRENT_BIT' Current RGBA color Current color index Current normal vector Current texture coordinates Current raster position `GL_CURRENT_RASTER_POSITION_VALID' flag RGBA color associated with current raster position Color index associated with current raster position Texture coordinates associated with current raster position `GL_EDGE_FLAG' flag `GL_DEPTH_BUFFER_BIT' `GL_DEPTH_TEST' enable bit Depth buffer test function Depth buffer clear value `GL_DEPTH_WRITEMASK' enable bit `GL_ENABLE_BIT' `GL_ALPHA_TEST' flag `GL_AUTO_NORMAL' flag `GL_BLEND' flag Enable bits for the user-definable clipping planes `GL_COLOR_MATERIAL' `GL_CULL_FACE' flag `GL_DEPTH_TEST' flag `GL_DITHER' flag `GL_FOG' flag `GL_LIGHT'I where `0' <= I < `GL_MAX_LIGHTS' `GL_LIGHTING' flag `GL_LINE_SMOOTH' flag `GL_LINE_STIPPLE' flag `GL_COLOR_LOGIC_OP' flag `GL_INDEX_LOGIC_OP' flag `GL_MAP1_'X where X is a map type `GL_MAP2_'X where X is a map type `GL_MULTISAMPLE' flag `GL_NORMALIZE' flag `GL_POINT_SMOOTH' flag `GL_POLYGON_OFFSET_LINE' flag `GL_POLYGON_OFFSET_FILL' flag `GL_POLYGON_OFFSET_POINT' flag `GL_POLYGON_SMOOTH' flag `GL_POLYGON_STIPPLE' flag `GL_SAMPLE_ALPHA_TO_COVERAGE' flag `GL_SAMPLE_ALPHA_TO_ONE' flag `GL_SAMPLE_COVERAGE' flag `GL_SCISSOR_TEST' flag `GL_STENCIL_TEST' flag `GL_TEXTURE_1D' flag `GL_TEXTURE_2D' flag `GL_TEXTURE_3D' flag Flags `GL_TEXTURE_GEN_'X where X is S, T, R, or Q `GL_EVAL_BIT' `GL_MAP1_'X enable bits, where X is a map type `GL_MAP2_'X enable bits, where X is a map type 1D grid endpoints and divisions 2D grid endpoints and divisions `GL_AUTO_NORMAL' enable bit `GL_FOG_BIT' `GL_FOG' enable bit Fog color Fog density Linear fog start Linear fog end Fog index `GL_FOG_MODE' value `GL_HINT_BIT' `GL_PERSPECTIVE_CORRECTION_HINT' setting `GL_POINT_SMOOTH_HINT' setting `GL_LINE_SMOOTH_HINT' setting `GL_POLYGON_SMOOTH_HINT' setting `GL_FOG_HINT' setting `GL_GENERATE_MIPMAP_HINT' setting `GL_TEXTURE_COMPRESSION_HINT' setting `GL_LIGHTING_BIT' `GL_COLOR_MATERIAL' enable bit `GL_COLOR_MATERIAL_FACE' value Color material parameters that are tracking the current color Ambient scene color `GL_LIGHT_MODEL_LOCAL_VIEWER' value `GL_LIGHT_MODEL_TWO_SIDE' setting `GL_LIGHTING' enable bit Enable bit for each light Ambient, diffuse, and specular intensity for each light Direction, position, exponent, and cutoff angle for each light Constant, linear, and quadratic attenuation factors for each light Ambient, diffuse, specular, and emissive color for each material Ambient, diffuse, and specular color indices for each material Specular exponent for each material `GL_SHADE_MODEL' setting `GL_LINE_BIT' `GL_LINE_SMOOTH' flag `GL_LINE_STIPPLE' enable bit Line stipple pattern and repeat counter Line width `GL_LIST_BIT' `GL_LIST_BASE' setting `GL_MULTISAMPLE_BIT' `GL_MULTISAMPLE' flag `GL_SAMPLE_ALPHA_TO_COVERAGE' flag `GL_SAMPLE_ALPHA_TO_ONE' flag `GL_SAMPLE_COVERAGE' flag `GL_SAMPLE_COVERAGE_VALUE' value `GL_SAMPLE_COVERAGE_INVERT' value `GL_PIXEL_MODE_BIT' `GL_RED_BIAS' and `GL_RED_SCALE' settings `GL_GREEN_BIAS' and `GL_GREEN_SCALE' values `GL_BLUE_BIAS' and `GL_BLUE_SCALE' `GL_ALPHA_BIAS' and `GL_ALPHA_SCALE' `GL_DEPTH_BIAS' and `GL_DEPTH_SCALE' `GL_INDEX_OFFSET' and `GL_INDEX_SHIFT' values `GL_MAP_COLOR' and `GL_MAP_STENCIL' flags `GL_ZOOM_X' and `GL_ZOOM_Y' factors `GL_READ_BUFFER' setting `GL_POINT_BIT' `GL_POINT_SMOOTH' flag Point size `GL_POLYGON_BIT' `GL_CULL_FACE' enable bit `GL_CULL_FACE_MODE' value `GL_FRONT_FACE' indicator `GL_POLYGON_MODE' setting `GL_POLYGON_SMOOTH' flag `GL_POLYGON_STIPPLE' enable bit `GL_POLYGON_OFFSET_FILL' flag `GL_POLYGON_OFFSET_LINE' flag `GL_POLYGON_OFFSET_POINT' flag `GL_POLYGON_OFFSET_FACTOR' `GL_POLYGON_OFFSET_UNITS' `GL_POLYGON_STIPPLE_BIT' Polygon stipple image `GL_SCISSOR_BIT' `GL_SCISSOR_TEST' flag Scissor box `GL_STENCIL_BUFFER_BIT' `GL_STENCIL_TEST' enable bit Stencil function and reference value Stencil value mask Stencil fail, pass, and depth buffer pass actions Stencil buffer clear value Stencil buffer writemask `GL_TEXTURE_BIT' Enable bits for the four texture coordinates Border color for each texture image Minification function for each texture image Magnification function for each texture image Texture coordinates and wrap mode for each texture image Color and mode for each texture environment Enable bits `GL_TEXTURE_GEN_'X, X is S, T, R, and Q `GL_TEXTURE_GEN_MODE' setting for S, T, R, and Q `glTexGen' plane equations for S, T, R, and Q Current texture bindings (for example, `GL_TEXTURE_BINDING_2D') `GL_TRANSFORM_BIT' Coefficients of the six clipping planes Enable bits for the user-definable clipping planes `GL_MATRIX_MODE' value `GL_NORMALIZE' flag `GL_RESCALE_NORMAL' flag `GL_VIEWPORT_BIT' Depth range (near and far) Viewport origin and extent `glPopAttrib' restores the values of the state variables saved with the last `glPushAttrib' command. Those not saved are left unchanged. It is an error to push attributes onto a full stack or to pop attributes off an empty stack. In either case, the error flag is set and no other change is made to GL state. Initially, the attribute stack is empty. `GL_STACK_OVERFLOW' is generated if `glPushAttrib' is called while the attribute stack is full. `GL_STACK_UNDERFLOW' is generated if `glPopAttrib' is called while the attribute stack is empty. `GL_INVALID_OPERATION' is generated if `glPushAttrib' or `glPopAttrib' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPushClientAttrib (mask GLbitfield) -> void) (glPopClientAttrib -> void)) "Push and pop the client attribute stack. MASK Specifies a mask that indicates which attributes to save. Values for MASK are listed below. `glPushClientAttrib' takes one argument, a mask that indicates which groups of client-state variables to save on the client attribute stack. Symbolic constants are used to set bits in the mask. MASK is typically constructed by specifying the bitwise-or of several of these constants together. The special mask `GL_CLIENT_ALL_ATTRIB_BITS' can be used to save all stackable client state. The symbolic mask constants and their associated GL client state are as follows (the second column lists which attributes are saved): `GL_CLIENT_PIXEL_STORE_BIT' Pixel storage modes `GL_CLIENT_VERTEX_ARRAY_BIT' Vertex arrays (and enables) `glPopClientAttrib' restores the values of the client-state variables saved with the last `glPushClientAttrib'. Those not saved are left unchanged. It is an error to push attributes onto a full client attribute stack or to pop attributes off an empty stack. In either case, the error flag is set, and no other change is made to GL state. Initially, the client attribute stack is empty. `GL_STACK_OVERFLOW' is generated if `glPushClientAttrib' is called while the attribute stack is full. `GL_STACK_UNDERFLOW' is generated if `glPopClientAttrib' is called while the attribute stack is empty.") (define-gl-procedures ((glPushMatrix -> void) (glPopMatrix -> void)) "Push and pop the current matrix stack. There is a stack of matrices for each of the matrix modes. In `GL_MODELVIEW' mode, the stack depth is at least 32. In the other modes, `GL_COLOR', `GL_PROJECTION', and `GL_TEXTURE', the depth is at least 2. The current matrix in any mode is the matrix on the top of the stack for that mode. `glPushMatrix' pushes the current matrix stack down by one, duplicating the current matrix. That is, after a `glPushMatrix' call, the matrix on top of the stack is identical to the one below it. `glPopMatrix' pops the current matrix stack, replacing the current matrix with the one below it on the stack. Initially, each of the stacks contains one matrix, an identity matrix. It is an error to push a full matrix stack or to pop a matrix stack that contains only a single matrix. In either case, the error flag is set and no other change is made to GL state. `GL_STACK_OVERFLOW' is generated if `glPushMatrix' is called while the current matrix stack is full. `GL_STACK_UNDERFLOW' is generated if `glPopMatrix' is called while the current matrix stack contains only a single matrix. `GL_INVALID_OPERATION' is generated if `glPushMatrix' or `glPopMatrix' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glPushName (name GLuint) -> void) (glPopName -> void)) "Push and pop the name stack. NAME Specifies a name that will be pushed onto the name stack. The name stack is used during selection mode to allow sets of rendering commands to be uniquely identified. It consists of an ordered set of unsigned integers and is initially empty. `glPushName' causes NAME to be pushed onto the name stack. `glPopName' pops one name off the top of the stack. The maximum name stack depth is implementation-dependent; call `GL_MAX_NAME_STACK_DEPTH' to find out the value for a particular implementation. It is an error to push a name onto a full stack or to pop a name off an empty stack. It is also an error to manipulate the name stack between the execution of `glBegin' and the corresponding execution of `glEnd'. In any of these cases, the error flag is set and no other change is made to GL state. The name stack is always empty while the render mode is not `GL_SELECT'. Calls to `glPushName' or `glPopName' while the render mode is not `GL_SELECT' are ignored. `GL_STACK_OVERFLOW' is generated if `glPushName' is called while the name stack is full. `GL_STACK_UNDERFLOW' is generated if `glPopName' is called while the name stack is empty. `GL_INVALID_OPERATION' is generated if `glPushName' or `glPopName' is executed between a call to `glBegin' and the corresponding call to `glEnd'.") (define-gl-procedures ((glRasterPos2i (x GLint) (y GLint) -> void) (glRasterPos2f (x GLfloat) (y GLfloat) -> void) (glRasterPos3i (x GLint) (y GLint) (z GLint) -> void) (glRasterPos3f (x GLfloat) (y GLfloat) (z GLfloat) -> void) (glRasterPos4i (x GLint) (y GLint) (z GLint) (w GLint) -> void) (glRasterPos4f (x GLfloat) (y GLfloat) (z GLfloat) (w GLfloat) -> void)) "Specify the raster position for pixel operations. X Y Z W Specify the X , Y , Z , and W object coordinates (if present) for the raster position. The GL maintains a 3D position in window coordinates. This position, called the raster position, is used to position pixel and bitmap write operations. It is maintained with subpixel accuracy. See `glBitmap', `glDrawPixels', and `glCopyPixels'. The current raster position consists of three window coordinates (X , Y , Z ), a clip coordinate value (W ), an eye coordinate distance, a valid bit, and associated color data and texture coordinates. The W coordinate is a clip coordinate, because W is not projected to window coordinates. `glRasterPos4' specifies object coordinates X , Y , Z , and W explicitly. `glRasterPos3' specifies object coordinate X , Y , and Z explicitly, while W is implicitly set to 1. `glRasterPos2' uses the argument values for X and Y while implicitly setting Z and W to 0 and 1. The object coordinates presented by `glRasterPos' are treated just like those of a `glVertex' command: They are transformed by the current modelview and projection matrices and passed to the clipping stage. If the vertex is not culled, then it is projected and scaled to window coordinates, which become the new current raster position, and the `GL_CURRENT_RASTER_POSITION_VALID' flag is set. If the vertex IS culled, then the valid bit is cleared and the current raster position and associated color and texture coordinates are undefined. The current raster position also includes some associated color data and texture coordinates. If lighting is enabled, then `GL_CURRENT_RASTER_COLOR' (in RGBA mode) or `GL_CURRENT_RASTER_INDEX' (in color index mode) is set to the color produced by the lighting calculation (see `glLight', `glLightModel', and `glShadeModel'). If lighting is disabled, current color (in RGBA mode, state variable `GL_CURRENT_COLOR') or color index (in color index mode, state variable `GL_CURRENT_INDEX') is used to update the current raster color. `GL_CURRENT_RASTER_SECONDARY_COLOR' (in RGBA mode) is likewise updated. Likewise, `GL_CURRENT_RASTER_TEXTURE_COORDS' is updated as a function of `GL_CURRENT_TEXTURE_COORDS', based on the texture matrix and the texture generation functions (see `glTexGen'). Finally, the distance from the origin of the eye coordinate system to the vertex as transformed by only the modelview matrix replaces `GL_CURRENT_RASTER_DISTANCE'. Initially, the current raster position is (0, 0, 0, 1), the current raster distance is 0, the valid bit is set, the associated RGBA color is (1, 1, 1, 1), the associated color index is 1, and the associated texture coordinates are (0, 0, 0, 1). In RGBA mode, `GL_CURRENT_RASTER_INDEX' is always 1; in color index mode, the current raster RGBA color always maintains its initial value. `GL_INVALID_OPERATION' is generated if `glRasterPos' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glReadBuffer (mode GLenum) -> void)) "Select a color buffer source for pixels. MODE Specifies a color buffer. Accepted values are `GL_FRONT_LEFT', `GL_FRONT_RIGHT', `GL_BACK_LEFT', `GL_BACK_RIGHT', `GL_FRONT', `GL_BACK', `GL_LEFT', `GL_RIGHT', and `GL_AUX'I, where I is between 0 and the value of `GL_AUX_BUFFERS' minus 1. `glReadBuffer' specifies a color buffer as the source for subsequent `glReadPixels', `glCopyTexImage1D', `glCopyTexImage2D', `glCopyTexSubImage1D', `glCopyTexSubImage2D', `glCopyTexSubImage3D', and `glCopyPixels' commands. MODE accepts one of twelve or more predefined values. (`GL_AUX0' through `GL_AUX3' are always defined.) In a fully configured system, `GL_FRONT', `GL_LEFT', and `GL_FRONT_LEFT' all name the front left buffer, `GL_FRONT_RIGHT' and `GL_RIGHT' name the front right buffer, and `GL_BACK_LEFT' and `GL_BACK' name the back left buffer. Nonstereo double-buffered configurations have only a front left and a back left buffer. Single-buffered configurations have a front left and a front right buffer if stereo, and only a front left buffer if nonstereo. It is an error to specify a nonexistent buffer to `glReadBuffer'. MODE is initially `GL_FRONT' in single-buffered configurations and `GL_BACK' in double-buffered configurations. `GL_INVALID_ENUM' is generated if MODE is not one of the twelve (or more) accepted values. `GL_INVALID_OPERATION' is generated if MODE specifies a buffer that does not exist. `GL_INVALID_OPERATION' is generated if `glReadBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glReadPixels (x GLint) (y GLint) (width GLsizei) (height GLsizei) (format GLenum) (type GLenum) (data GLvoid-*) -> void)) "Read a block of pixels from the frame buffer. X Y Specify the window coordinates of the first pixel that is read from the frame buffer. This location is the lower left corner of a rectangular block of pixels. WIDTH HEIGHT Specify the dimensions of the pixel rectangle. WIDTH and HEIGHT of one correspond to a single pixel. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_STENCIL_INDEX', `GL_DEPTH_COMPONENT', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. Must be one of `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Returns the pixel data. `glReadPixels' returns pixel data from the frame buffer, starting with the pixel whose lower left corner is at location (X, Y), into client memory starting at location DATA. Several parameters control the processing of the pixel data before it is placed into client memory. These parameters are set with three commands: `glPixelStore', `glPixelTransfer', and `glPixelMap'. This reference page describes the effects on `glReadPixels' of most, but not all of the parameters specified by these three commands. If a non-zero named buffer object is bound to the `GL_PIXEL_PACK_BUFFER' target (see `glBindBuffer') while a block of pixels is requested, DATA is treated as a byte offset into the buffer object's data store rather than a pointer to client memory. When the `ARB_imaging' extension is supported, the pixel data may be processed by additional operations including color table lookup, color matrix transformations, convolutions, histograms, and minimum and maximum pixel value computations. `glReadPixels' returns values from each pixel with lower left corner at (X+I,Y+J) for 0<=I void) (glRecti (x1 GLint) (y1 GLint) (x2 GLint) (y2 GLint) -> void)) "Draw a rectangle. X1 Y1 Specify one vertex of a rectangle. X2 Y2 Specify the opposite vertex of the rectangle. `glRect' supports efficient specification of rectangles as two corner points. Each rectangle command takes four arguments, organized either as two consecutive pairs of (X,Y) coordinates or as two pointers to arrays, each containing an (X,Y) pair. The resulting rectangle is defined in the Z=0 plane. `glRect'(X1, Y1, X2, Y2) is exactly equivalent to the following sequence: Note that if the second vertex is above and to the right of the first vertex, the rectangle is constructed with a counterclockwise winding. glBegin(`GL_POLYGON'); glVertex2(X1, Y1); glVertex2(X2, Y1); glVertex2(X2, Y2); glVertex2(X1, Y2); glEnd(); `GL_INVALID_OPERATION' is generated if `glRect' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glRenderMode (mode GLenum) -> GLint)) "Set rasterization mode. MODE Specifies the rasterization mode. Three values are accepted: `GL_RENDER', `GL_SELECT', and `GL_FEEDBACK'. The initial value is `GL_RENDER'. `glRenderMode' sets the rasterization mode. It takes one argument, MODE, which can assume one of three predefined values: `GL_RENDER' Render mode. Primitives are rasterized, producing pixel fragments, which are written into the frame buffer. This is the normal mode and also the default mode. `GL_SELECT' Selection mode. No pixel fragments are produced, and no change to the frame buffer contents is made. Instead, a record of the names of primitives that would have been drawn if the render mode had been `GL_RENDER' is returned in a select buffer, which must be created (see `glSelectBuffer') before selection mode is entered. `GL_FEEDBACK' Feedback mode. No pixel fragments are produced, and no change to the frame buffer contents is made. Instead, the coordinates and attributes of vertices that would have been drawn if the render mode had been `GL_RENDER' is returned in a feedback buffer, which must be created (see `glFeedbackBuffer') before feedback mode is entered. The return value of `glRenderMode' is determined by the render mode at the time `glRenderMode' is called, rather than by MODE. The values returned for the three render modes are as follows: `GL_RENDER' 0. `GL_SELECT' The number of hit records transferred to the select buffer. `GL_FEEDBACK' The number of values (not vertices) transferred to the feedback buffer. See the `glSelectBuffer' and `glFeedbackBuffer' reference pages for more details concerning selection and feedback operation. `GL_INVALID_ENUM' is generated if MODE is not one of the three accepted values. `GL_INVALID_OPERATION' is generated if `glSelectBuffer' is called while the render mode is `GL_SELECT', or if `glRenderMode' is called with argument `GL_SELECT' before `glSelectBuffer' is called at least once. `GL_INVALID_OPERATION' is generated if `glFeedbackBuffer' is called while the render mode is `GL_FEEDBACK', or if `glRenderMode' is called with argument `GL_FEEDBACK' before `glFeedbackBuffer' is called at least once. `GL_INVALID_OPERATION' is generated if `glRenderMode' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glResetHistogram (target GLenum) -> void)) "Reset histogram table entries to zero. TARGET Must be `GL_HISTOGRAM'. `glResetHistogram' resets all the elements of the current histogram table to zero. `GL_INVALID_ENUM' is generated if TARGET is not `GL_HISTOGRAM'. `GL_INVALID_OPERATION' is generated if `glResetHistogram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glResetMinmax (target GLenum) -> void)) "Reset minmax table entries to initial values. TARGET Must be `GL_MINMAX'. `glResetMinmax' resets the elements of the current minmax table to their initial values: the ``maximum'' element receives the minimum possible component values, and the ``minimum'' element receives the maximum possible component values. `GL_INVALID_ENUM' is generated if TARGET is not `GL_MINMAX'. `GL_INVALID_OPERATION' is generated if `glResetMinmax' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glRotatef (angle GLfloat) (x GLfloat) (y GLfloat) (z GLfloat) -> void)) "Multiply the current matrix by a rotation matrix. ANGLE Specifies the angle of rotation, in degrees. X Y Z Specify the X, Y, and Z coordinates of a vector, respectively. `glRotate' produces a rotation of ANGLE degrees around the vector (X,YZ) . The current matrix (see `glMatrixMode') is multiplied by a rotation matrix with the product replacing the current matrix, as if `glMultMatrix' were called with the following matrix as its argument: ((X^2\u2061(1-C,)+C X\u2062Y\u2061(1-C,)-Z\u2062S X\u2062Z\u2061(1-C,)+Y\u2062S 0), (Y\u2062X\u2061(1-C,)+Z\u2062S Y^2\u2061(1-C,)+C Y\u2062Z\u2061(1-C,)-X\u2062S 0), (X\u2062Z\u2061(1-C,)-Y\u2062S Y\u2062Z\u2061(1-C,)+X\u2062S Z^2\u2061(1-C,)+C 0), (0 0 0 1),) Where C=COS\u2061(ANGLE,) , S=SIN\u2061(ANGLE,) , and ∥(X,YZ),∥=1 (if not, the GL will normalize this vector). If the matrix mode is either `GL_MODELVIEW' or `GL_PROJECTION', all objects drawn after `glRotate' is called are rotated. Use `glPushMatrix' and `glPopMatrix' to save and restore the unrotated coordinate system. `GL_INVALID_OPERATION' is generated if `glRotate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glSampleCoverage (value GLclampf) (invert GLboolean) -> void)) "Specify multisample coverage parameters. VALUE Specify a single floating-point sample coverage value. The value is clamped to the range [0,1] . The initial value is 1.0. INVERT Specify a single boolean value representing if the coverage masks should be inverted. `GL_TRUE' and `GL_FALSE' are accepted. The initial value is `GL_FALSE'. Multisampling samples a pixel multiple times at various implementation-dependent subpixel locations to generate antialiasing effects. Multisampling transparently antialiases points, lines, polygons, bitmaps, and images if it is enabled. VALUE is used in constructing a temporary mask used in determining which samples will be used in resolving the final fragment color. This mask is bitwise-anded with the coverage mask generated from the multisampling computation. If the INVERT flag is set, the temporary mask is inverted (all bits flipped) and then the bitwise-and is computed. If an implementation does not have any multisample buffers available, or multisampling is disabled, rasterization occurs with only a single sample computing a pixel's final RGB color. Provided an implementation supports multisample buffers, and multisampling is enabled, then a pixel's final color is generated by combining several samples per pixel. Each sample contains color, depth, and stencil information, allowing those operations to be performed on each sample. `GL_INVALID_OPERATION' is generated if `glSampleCoverage' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glScalef (x GLfloat) (y GLfloat) (z GLfloat) -> void)) "Multiply the current matrix by a general scaling matrix. X Y Z Specify scale factors along the X, Y, and Z axes, respectively. `glScale' produces a nonuniform scaling along the X, Y, and Z axes. The three parameters indicate the desired scale factor along each of the three axes. The current matrix (see `glMatrixMode') is multiplied by this scale matrix, and the product replaces the current matrix as if `glMultMatrix' were called with the following matrix as its argument: ((X 0 0 0), (0 Y 0 0), (0 0 Z 0), (0 0 0 1),) If the matrix mode is either `GL_MODELVIEW' or `GL_PROJECTION', all objects drawn after `glScale' is called are scaled. Use `glPushMatrix' and `glPopMatrix' to save and restore the unscaled coordinate system. `GL_INVALID_OPERATION' is generated if `glScale' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glScissor (x GLint) (y GLint) (width GLsizei) (height GLsizei) -> void)) "Define the scissor box. X Y Specify the lower left corner of the scissor box. Initially (0, 0). WIDTH HEIGHT Specify the width and height of the scissor box. When a GL context is first attached to a window, WIDTH and HEIGHT are set to the dimensions of that window. `glScissor' defines a rectangle, called the scissor box, in window coordinates. The first two arguments, X and Y, specify the lower left corner of the box. WIDTH and HEIGHT specify the width and height of the box. To enable and disable the scissor test, call `glEnable' and `glDisable' with argument `GL_SCISSOR_TEST'. The test is initially disabled. While the test is enabled, only pixels that lie within the scissor box can be modified by drawing commands. Window coordinates have integer values at the shared corners of frame buffer pixels. `glScissor(0,0,1,1)' allows modification of only the lower left pixel in the window, and `glScissor(0,0,0,0)' doesn't allow modification of any pixels in the window. When the scissor test is disabled, it is as though the scissor box includes the entire window. `GL_INVALID_VALUE' is generated if either WIDTH or HEIGHT is negative. `GL_INVALID_OPERATION' is generated if `glScissor' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glSecondaryColorPointer (size GLint) (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of secondary colors. SIZE Specifies the number of components per color. Must be 3. TYPE Specifies the data type of each color component in the array. Symbolic constants `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', or `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive colors. If STRIDE is 0, the colors are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first component of the first color element in the array. The initial value is 0. `glSecondaryColorPointer' specifies the location and data format of an array of color components to use when rendering. SIZE specifies the number of components per color, and must be 3. TYPE specifies the data type of each color component, and STRIDE specifies the byte stride from one color to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a secondary color array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as secondary color vertex array client-side state (`GL_SECONDARY_COLOR_ARRAY_BUFFER_BINDING'). When a secondary color array is specified, SIZE, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the secondary color array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_SECONDARY_COLOR_ARRAY'. If enabled, the secondary color array is used when `glArrayElement', `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', or `glDrawRangeElements' is called. `GL_INVALID_VALUE' is generated if SIZE is not 3. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glSecondaryColor3i (red GLint) (green GLint) (blue GLint) -> void) (glSecondaryColor3f (red GLfloat) (green GLfloat) (blue GLfloat) -> void) (glSecondaryColor3ui (red GLuint) (green GLuint) (blue GLuint) -> void)) "Set the current secondary color. RED GREEN BLUE Specify new red, green, and blue values for the current secondary color. The GL stores both a primary four-valued RGBA color and a secondary four-valued RGBA color (where alpha is always set to 0.0) that is associated with every vertex. The secondary color is interpolated and applied to each fragment during rasterization when `GL_COLOR_SUM' is enabled. When lighting is enabled, and `GL_SEPARATE_SPECULAR_COLOR' is specified, the value of the secondary color is assigned the value computed from the specular term of the lighting computation. Both the primary and secondary current colors are applied to each fragment, regardless of the state of `GL_COLOR_SUM', under such conditions. When `GL_SEPARATE_SPECULAR_COLOR' is specified, the value returned from querying the current secondary color is undefined. `glSecondaryColor3b', `glSecondaryColor3s', and `glSecondaryColor3i' take three signed byte, short, or long integers as arguments. When *v* is appended to the name, the color commands can take a pointer to an array of such values. Color values are stored in floating-point format, with unspecified mantissa and exponent sizes. Unsigned integer color components, when specified, are linearly mapped to floating-point values such that the largest representable value maps to 1.0 (full intensity), and 0 maps to 0.0 (zero intensity). Signed integer color components, when specified, are linearly mapped to floating-point values such that the most positive representable value maps to 1.0, and the most negative representable value maps to -1.0 . (Note that this mapping does not convert 0 precisely to 0.0). Floating-point values are mapped directly. Neither floating-point nor signed integer values are clamped to the range [0,1] before the current color is updated. However, color components are clamped to this range before they are interpolated or written into a color buffer.") (define-gl-procedures ((glSelectBuffer (size GLsizei) (buffer GLuint-*) -> void)) "Establish a buffer for selection mode values. SIZE Specifies the size of BUFFER. BUFFER Returns the selection data. `glSelectBuffer' has two arguments: BUFFER is a pointer to an array of unsigned integers, and SIZE indicates the size of the array. BUFFER returns values from the name stack (see `glInitNames', `glLoadName', `glPushName') when the rendering mode is `GL_SELECT' (see `glRenderMode'). `glSelectBuffer' must be issued before selection mode is enabled, and it must not be issued while the rendering mode is `GL_SELECT'. A programmer can use selection to determine which primitives are drawn into some region of a window. The region is defined by the current modelview and perspective matrices. In selection mode, no pixel fragments are produced from rasterization. Instead, if a primitive or a raster position intersects the clipping volume defined by the viewing frustum and the user-defined clipping planes, this primitive causes a selection hit. (With polygons, no hit occurs if the polygon is culled.) When a change is made to the name stack, or when `glRenderMode' is called, a hit record is copied to BUFFER if any hits have occurred since the last such event (name stack change or `glRenderMode' call). The hit record consists of the number of names in the name stack at the time of the event, followed by the minimum and maximum depth values of all vertices that hit since the previous event, followed by the name stack contents, bottom name first. Depth values (which are in the range [0,1]) are multiplied by 2^32-1 , before being placed in the hit record. An internal index into BUFFER is reset to 0 whenever selection mode is entered. Each time a hit record is copied into BUFFER, the index is incremented to point to the cell just past the end of the block of names\\(emthat is, to the next available cell If the hit record is larger than the number of remaining locations in BUFFER, as much data as can fit is copied, and the overflow flag is set. If the name stack is empty when a hit record is copied, that record consists of 0 followed by the minimum and maximum depth values. To exit selection mode, call `glRenderMode' with an argument other than `GL_SELECT'. Whenever `glRenderMode' is called while the render mode is `GL_SELECT', it returns the number of hit records copied to BUFFER, resets the overflow flag and the selection buffer pointer, and initializes the name stack to be empty. If the overflow bit was set when `glRenderMode' was called, a negative hit record count is returned. `GL_INVALID_VALUE' is generated if SIZE is negative. `GL_INVALID_OPERATION' is generated if `glSelectBuffer' is called while the render mode is `GL_SELECT', or if `glRenderMode' is called with argument `GL_SELECT' before `glSelectBuffer' is called at least once. `GL_INVALID_OPERATION' is generated if `glSelectBuffer' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glSeparableFilter2D (target GLenum) (internalformat GLenum) (width GLsizei) (height GLsizei) (format GLenum) (type GLenum) (row const-GLvoid-*) (column const-GLvoid-*) -> void)) "Define a separable two-dimensional convolution filter. TARGET Must be `GL_SEPARABLE_2D'. INTERNALFORMAT The internal format of the convolution filter kernel. The allowable values are `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', or `GL_RGBA16'. WIDTH The number of elements in the pixel array referenced by ROW. (This is the width of the separable filter kernel.) HEIGHT The number of elements in the pixel array referenced by COLUMN. (This is the height of the separable filter kernel.) FORMAT The format of the pixel data in ROW and COLUMN. The allowable values are `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_INTENSITY', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE The type of the pixel data in ROW and COLUMN. Symbolic constants `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV' are accepted. ROW Pointer to a one-dimensional array of pixel data that is processed to build the row filter kernel. COLUMN Pointer to a one-dimensional array of pixel data that is processed to build the column filter kernel. `glSeparableFilter2D' builds a two-dimensional separable convolution filter kernel from two arrays of pixels. The pixel arrays specified by (WIDTH, FORMAT, TYPE, ROW) and (HEIGHT, FORMAT, TYPE, COLUMN) are processed just as if they had been passed to `glDrawPixels', but processing stops after the final expansion to RGBA is completed. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a convolution filter is specified, ROW and COLUMN are treated as byte offsets into the buffer object's data store. Next, the R, G, B, and A components of all pixels in both arrays are scaled by the four separable 2D `GL_CONVOLUTION_FILTER_SCALE' parameters and biased by the four separable 2D `GL_CONVOLUTION_FILTER_BIAS' parameters. (The scale and bias parameters are set by `glConvolutionParameter' using the `GL_SEPARABLE_2D' target and the names `GL_CONVOLUTION_FILTER_SCALE' and `GL_CONVOLUTION_FILTER_BIAS'. The parameters themselves are vectors of four values that are applied to red, green, blue, and alpha, in that order.) The R, G, B, and A values are not clamped to [0,1] at any time during this process. Each pixel is then converted to the internal format specified by INTERNALFORMAT. This conversion simply maps the component values of the pixel (R, G, B, and A) to the values included in the internal format (red, green, blue, alpha, luminance, and intensity). The mapping is as follows: *Internal Format* *Red*, *Green*, *Blue*, *Alpha*, *Luminance*, *Intensity* `GL_LUMINANCE' , , , , R , `GL_LUMINANCE_ALPHA' , , , A , R , `GL_INTENSITY' , , , , , R `GL_RGB' R , G , B , , , `GL_RGBA' R , G , B , A , , The red, green, blue, alpha, luminance, and/or intensity components of the resulting pixels are stored in floating-point rather than integer format. They form two one-dimensional filter kernel images. The row image is indexed by coordinate I starting at zero and increasing from left to right. Each location in the row image is derived from element I of ROW. The column image is indexed by coordinate J starting at zero and increasing from bottom to top. Each location in the column image is derived from element J of COLUMN. Note that after a convolution is performed, the resulting color components are also scaled by their corresponding `GL_POST_CONVOLUTION_c_SCALE' parameters and biased by their corresponding `GL_POST_CONVOLUTION_c_BIAS' parameters (where C takes on the values *RED*, *GREEN*, *BLUE*, and *ALPHA*). These parameters are set by `glPixelTransfer'. `GL_INVALID_ENUM' is generated if TARGET is not `GL_SEPARABLE_2D'. `GL_INVALID_ENUM' is generated if INTERNALFORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not one of the allowable values. `GL_INVALID_ENUM' is generated if TYPE is not one of the allowable values. `GL_INVALID_VALUE' is generated if WIDTH is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_SEPARABLE_2D' and name `GL_MAX_CONVOLUTION_WIDTH'. `GL_INVALID_VALUE' is generated if HEIGHT is less than zero or greater than the maximum supported value. This value may be queried with `glGetConvolutionParameter' using target `GL_SEPARABLE_2D' and name `GL_MAX_CONVOLUTION_HEIGHT'. `GL_INVALID_OPERATION' is generated if HEIGHT is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if HEIGHT is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and ROW or COLUMN is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glSeparableFilter2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glShadeModel (mode GLenum) -> void)) "Select flat or smooth shading. MODE Specifies a symbolic value representing a shading technique. Accepted values are `GL_FLAT' and `GL_SMOOTH'. The initial value is `GL_SMOOTH'. GL primitives can have either flat or smooth shading. Smooth shading, the default, causes the computed colors of vertices to be interpolated as the primitive is rasterized, typically assigning different colors to each resulting pixel fragment. Flat shading selects the computed color of just one vertex and assigns it to all the pixel fragments generated by rasterizing a single primitive. In either case, the computed color of a vertex is the result of lighting if lighting is enabled, or it is the current color at the time the vertex was specified if lighting is disabled. Flat and smooth shading are indistinguishable for points. Starting when `glBegin' is issued and counting vertices and primitives from 1, the GL gives each flat-shaded line segment I the computed color of vertex I+1 , its second vertex. Counting similarly from 1, the GL gives each flat-shaded polygon the computed color of the vertex listed in the following table. This is the last vertex to specify the polygon in all cases except single polygons, where the first vertex specifies the flat-shaded color. * Primitive Type of Polygon I * *Vertex* Single polygon (I==1 ) 1 Triangle strip I+2 Triangle fan I+2 Independent triangle 3\u2062I Quad strip 2\u2062I+2 Independent quad 4\u2062I Flat and smooth shading are specified by `glShadeModel' with MODE set to `GL_FLAT' and `GL_SMOOTH', respectively. `GL_INVALID_ENUM' is generated if MODE is any value other than `GL_FLAT' or `GL_SMOOTH'. `GL_INVALID_OPERATION' is generated if `glShadeModel' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glShaderSource (shader GLuint) (count GLsizei) (string const-GLchar-**) (length const-GLint-*) -> void)) "Replaces the source code in a shader object. SHADER Specifies the handle of the shader object whose source code is to be replaced. COUNT Specifies the number of elements in the STRING and LENGTH arrays. STRING Specifies an array of pointers to strings containing the source code to be loaded into the shader. LENGTH Specifies an array of string lengths. `glShaderSource' sets the source code in SHADER to the source code in the array of strings specified by STRING. Any source code previously stored in the shader object is completely replaced. The number of strings in the array is specified by COUNT. If LENGTH is `NULL', each string is assumed to be null terminated. If LENGTH is a value other than `NULL', it points to an array containing a string length for each of the corresponding elements of STRING. Each element in the LENGTH array may contain the length of the corresponding string (the null character is not counted as part of the string length) or a value less than 0 to indicate that the string is null terminated. The source code strings are not scanned or parsed at this time; they are simply copied into the specified shader object. `GL_INVALID_VALUE' is generated if SHADER is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if SHADER is not a shader object. `GL_INVALID_VALUE' is generated if COUNT is less than 0. `GL_INVALID_OPERATION' is generated if `glShaderSource' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilFuncSeparate (face GLenum) (func GLenum) (ref GLint) (mask GLuint) -> void)) "Set front and/or back function and reference value for stencil testing. FACE Specifies whether front and/or back stencil state is updated. Three symbolic constants are valid: `GL_FRONT', `GL_BACK', and `GL_FRONT_AND_BACK'. FUNC Specifies the test function. Eight symbolic constants are valid: `GL_NEVER', `GL_LESS', `GL_LEQUAL', `GL_GREATER', `GL_GEQUAL', `GL_EQUAL', `GL_NOTEQUAL', and `GL_ALWAYS'. The initial value is `GL_ALWAYS'. REF Specifies the reference value for the stencil test. REF is clamped to the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. The initial value is 0. MASK Specifies a mask that is ANDed with both the reference value and the stored stencil value when the test is done. The initial value is all 1's. Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the reference value and the value in the stencil buffer. To enable and disable the test, call `glEnable' and `glDisable' with argument `GL_STENCIL_TEST'. To specify actions based on the outcome of the stencil test, call `glStencilOp' or `glStencilOpSeparate'. There can be two separate sets of FUNC, REF, and MASK parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilFunc' sets both front and back stencil state to the same values, as if `glStencilFuncSeparate' were called with FACE set to `GL_FRONT_AND_BACK'. FUNC is a symbolic constant that determines the stencil comparison function. It accepts one of eight values, shown in the following list. REF is an integer reference value that is used in the stencil comparison. It is clamped to the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. MASK is bitwise ANDed with both the reference value and the stored stencil value, with the ANDed values participating in the comparison. If STENCIL represents the value stored in the corresponding stencil buffer location, the following list shows the effect of each comparison function that can be specified by FUNC. Only if the comparison succeeds is the pixel passed through to the next stage in the rasterization process (see `glStencilOp'). All tests treat STENCIL values as unsigned integers in the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. The following values are accepted by FUNC: `GL_NEVER' Always fails. `GL_LESS' Passes if ( REF & MASK ) < ( STENCIL & MASK ). `GL_LEQUAL' Passes if ( REF & MASK ) <= ( STENCIL & MASK ). `GL_GREATER' Passes if ( REF & MASK ) > ( STENCIL & MASK ). `GL_GEQUAL' Passes if ( REF & MASK ) >= ( STENCIL & MASK ). `GL_EQUAL' Passes if ( REF & MASK ) = ( STENCIL & MASK ). `GL_NOTEQUAL' Passes if ( REF & MASK ) != ( STENCIL & MASK ). `GL_ALWAYS' Always passes. `GL_INVALID_ENUM' is generated if FUNC is not one of the eight accepted values. `GL_INVALID_OPERATION' is generated if `glStencilFuncSeparate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilFunc (func GLenum) (ref GLint) (mask GLuint) -> void)) "Set front and back function and reference value for stencil testing. FUNC Specifies the test function. Eight symbolic constants are valid: `GL_NEVER', `GL_LESS', `GL_LEQUAL', `GL_GREATER', `GL_GEQUAL', `GL_EQUAL', `GL_NOTEQUAL', and `GL_ALWAYS'. The initial value is `GL_ALWAYS'. REF Specifies the reference value for the stencil test. REF is clamped to the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. The initial value is 0. MASK Specifies a mask that is ANDed with both the reference value and the stored stencil value when the test is done. The initial value is all 1's. Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. Stencil planes are first drawn into using GL drawing primitives, then geometry and images are rendered using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the reference value and the value in the stencil buffer. To enable and disable the test, call `glEnable' and `glDisable' with argument `GL_STENCIL_TEST'. To specify actions based on the outcome of the stencil test, call `glStencilOp' or `glStencilOpSeparate'. There can be two separate sets of FUNC, REF, and MASK parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilFunc' sets both front and back stencil state to the same values. Use `glStencilFuncSeparate' to set front and back stencil state to different values. FUNC is a symbolic constant that determines the stencil comparison function. It accepts one of eight values, shown in the following list. REF is an integer reference value that is used in the stencil comparison. It is clamped to the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. MASK is bitwise ANDed with both the reference value and the stored stencil value, with the ANDed values participating in the comparison. If STENCIL represents the value stored in the corresponding stencil buffer location, the following list shows the effect of each comparison function that can be specified by FUNC. Only if the comparison succeeds is the pixel passed through to the next stage in the rasterization process (see `glStencilOp'). All tests treat STENCIL values as unsigned integers in the range [0,2^N-1] , where N is the number of bitplanes in the stencil buffer. The following values are accepted by FUNC: `GL_NEVER' Always fails. `GL_LESS' Passes if ( REF & MASK ) < ( STENCIL & MASK ). `GL_LEQUAL' Passes if ( REF & MASK ) <= ( STENCIL & MASK ). `GL_GREATER' Passes if ( REF & MASK ) > ( STENCIL & MASK ). `GL_GEQUAL' Passes if ( REF & MASK ) >= ( STENCIL & MASK ). `GL_EQUAL' Passes if ( REF & MASK ) = ( STENCIL & MASK ). `GL_NOTEQUAL' Passes if ( REF & MASK ) != ( STENCIL & MASK ). `GL_ALWAYS' Always passes. `GL_INVALID_ENUM' is generated if FUNC is not one of the eight accepted values. `GL_INVALID_OPERATION' is generated if `glStencilFunc' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilMaskSeparate (face GLenum) (mask GLuint) -> void)) "Control the front and/or back writing of individual bits in the stencil planes. FACE Specifies whether the front and/or back stencil writemask is updated. Three symbolic constants are valid: `GL_FRONT', `GL_BACK', and `GL_FRONT_AND_BACK'. MASK Specifies a bit mask to enable and disable writing of individual bits in the stencil planes. Initially, the mask is all 1's. `glStencilMaskSeparate' controls the writing of individual bits in the stencil planes. The least significant N bits of MASK, where N is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing. There can be two separate MASK writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilMask' sets both front and back stencil writemasks to the same values, as if `glStencilMaskSeparate' were called with FACE set to `GL_FRONT_AND_BACK'. `GL_INVALID_OPERATION' is generated if `glStencilMaskSeparate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilMask (mask GLuint) -> void)) "Control the front and back writing of individual bits in the stencil planes. MASK Specifies a bit mask to enable and disable writing of individual bits in the stencil planes. Initially, the mask is all 1's. `glStencilMask' controls the writing of individual bits in the stencil planes. The least significant N bits of MASK, where N is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing. There can be two separate MASK writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilMask' sets both front and back stencil writemasks to the same values. Use `glStencilMaskSeparate' to set front and back stencil writemasks to different values. `GL_INVALID_OPERATION' is generated if `glStencilMask' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilOpSeparate (face GLenum) (sfail GLenum) (dpfail GLenum) (dppass GLenum) -> void)) "Set front and/or back stencil test actions. FACE Specifies whether front and/or back stencil state is updated. Three symbolic constants are valid: `GL_FRONT', `GL_BACK', and `GL_FRONT_AND_BACK'. SFAIL Specifies the action to take when the stencil test fails. Eight symbolic constants are accepted: `GL_KEEP', `GL_ZERO', `GL_REPLACE', `GL_INCR', `GL_INCR_WRAP', `GL_DECR', `GL_DECR_WRAP', and `GL_INVERT'. The initial value is `GL_KEEP'. DPFAIL Specifies the stencil action when the stencil test passes, but the depth test fails. DPFAIL accepts the same symbolic constants as SFAIL. The initial value is `GL_KEEP'. DPPASS Specifies the stencil action when both the stencil test and the depth test pass, or when the stencil test passes and either there is no depth buffer or depth testing is not enabled. DPPASS accepts the same symbolic constants as SFAIL. The initial value is `GL_KEEP'. Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the value in the stencil buffer and a reference value. To enable and disable the test, call `glEnable' and `glDisable' with argument `GL_STENCIL_TEST'; to control it, call `glStencilFunc' or `glStencilFuncSeparate'. There can be two separate sets of SFAIL, DPFAIL, and DPPASS parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilOp' sets both front and back stencil state to the same values, as if `glStencilOpSeparate' were called with FACE set to `GL_FRONT_AND_BACK'. `glStencilOpSeparate' takes three arguments that indicate what happens to the stored stencil value while stenciling is enabled. If the stencil test fails, no change is made to the pixel's color or depth buffers, and SFAIL specifies what happens to the stencil buffer contents. The following eight actions are possible. `GL_KEEP' Keeps the current value. `GL_ZERO' Sets the stencil buffer value to 0. `GL_REPLACE' Sets the stencil buffer value to REF, as specified by `glStencilFunc'. `GL_INCR' Increments the current stencil buffer value. Clamps to the maximum representable unsigned value. `GL_INCR_WRAP' Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value. `GL_DECR' Decrements the current stencil buffer value. Clamps to 0. `GL_DECR_WRAP' Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero. `GL_INVERT' Bitwise inverts the current stencil buffer value. Stencil buffer values are treated as unsigned integers. When incremented and decremented, values are clamped to 0 and 2^N-1 , where N is the value returned by querying `GL_STENCIL_BITS'. The other two arguments to `glStencilOpSeparate' specify stencil buffer actions that depend on whether subsequent depth buffer tests succeed (DPPASS) or fail (DPFAIL) (see `glDepthFunc'). The actions are specified using the same eight symbolic constants as SFAIL. Note that DPFAIL is ignored when there is no depth buffer, or when the depth buffer is not enabled. In these cases, SFAIL and DPPASS specify stencil action when the stencil test fails and passes, respectively. `GL_INVALID_ENUM' is generated if FACE is any value other than `GL_FRONT', `GL_BACK', or `GL_FRONT_AND_BACK'. `GL_INVALID_ENUM' is generated if SFAIL, DPFAIL, or DPPASS is any value other than the eight defined constant values. `GL_INVALID_OPERATION' is generated if `glStencilOpSeparate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glStencilOp (sfail GLenum) (dpfail GLenum) (dppass GLenum) -> void)) "Set front and back stencil test actions. SFAIL Specifies the action to take when the stencil test fails. Eight symbolic constants are accepted: `GL_KEEP', `GL_ZERO', `GL_REPLACE', `GL_INCR', `GL_INCR_WRAP', `GL_DECR', `GL_DECR_WRAP', and `GL_INVERT'. The initial value is `GL_KEEP'. DPFAIL Specifies the stencil action when the stencil test passes, but the depth test fails. DPFAIL accepts the same symbolic constants as SFAIL. The initial value is `GL_KEEP'. DPPASS Specifies the stencil action when both the stencil test and the depth test pass, or when the stencil test passes and either there is no depth buffer or depth testing is not enabled. DPPASS accepts the same symbolic constants as SFAIL. The initial value is `GL_KEEP'. Stenciling, like depth-buffering, enables and disables drawing on a per-pixel basis. You draw into the stencil planes using GL drawing primitives, then render geometry and images, using the stencil planes to mask out portions of the screen. Stenciling is typically used in multipass rendering algorithms to achieve special effects, such as decals, outlining, and constructive solid geometry rendering. The stencil test conditionally eliminates a pixel based on the outcome of a comparison between the value in the stencil buffer and a reference value. To enable and disable the test, call `glEnable' and `glDisable' with argument `GL_STENCIL_TEST'; to control it, call `glStencilFunc' or `glStencilFuncSeparate'. There can be two separate sets of SFAIL, DPFAIL, and DPPASS parameters; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. `glStencilOp' sets both front and back stencil state to the same values. Use `glStencilOpSeparate' to set front and back stencil state to different values. `glStencilOp' takes three arguments that indicate what happens to the stored stencil value while stenciling is enabled. If the stencil test fails, no change is made to the pixel's color or depth buffers, and SFAIL specifies what happens to the stencil buffer contents. The following eight actions are possible. `GL_KEEP' Keeps the current value. `GL_ZERO' Sets the stencil buffer value to 0. `GL_REPLACE' Sets the stencil buffer value to REF, as specified by `glStencilFunc'. `GL_INCR' Increments the current stencil buffer value. Clamps to the maximum representable unsigned value. `GL_INCR_WRAP' Increments the current stencil buffer value. Wraps stencil buffer value to zero when incrementing the maximum representable unsigned value. `GL_DECR' Decrements the current stencil buffer value. Clamps to 0. `GL_DECR_WRAP' Decrements the current stencil buffer value. Wraps stencil buffer value to the maximum representable unsigned value when decrementing a stencil buffer value of zero. `GL_INVERT' Bitwise inverts the current stencil buffer value. Stencil buffer values are treated as unsigned integers. When incremented and decremented, values are clamped to 0 and 2^N-1 , where N is the value returned by querying `GL_STENCIL_BITS'. The other two arguments to `glStencilOp' specify stencil buffer actions that depend on whether subsequent depth buffer tests succeed (DPPASS) or fail (DPFAIL) (see `glDepthFunc'). The actions are specified using the same eight symbolic constants as SFAIL. Note that DPFAIL is ignored when there is no depth buffer, or when the depth buffer is not enabled. In these cases, SFAIL and DPPASS specify stencil action when the stencil test fails and passes, respectively. `GL_INVALID_ENUM' is generated if SFAIL, DPFAIL, or DPPASS is any value other than the eight defined constant values. `GL_INVALID_OPERATION' is generated if `glStencilOp' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexCoordPointer (size GLint) (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of texture coordinates. SIZE Specifies the number of coordinates per array element. Must be 1, 2, 3, or 4. The initial value is 4. TYPE Specifies the data type of each texture coordinate. Symbolic constants `GL_SHORT', `GL_INT', `GL_FLOAT', or `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive texture coordinate sets. If STRIDE is 0, the array elements are understood to be tightly packed. The initial value is 0. POINTER Specifies a pointer to the first coordinate of the first texture coordinate set in the array. The initial value is 0. `glTexCoordPointer' specifies the location and data format of an array of texture coordinates to use when rendering. SIZE specifies the number of coordinates per texture coordinate set, and must be 1, 2, 3, or 4. TYPE specifies the data type of each texture coordinate, and STRIDE specifies the byte stride from one texture coordinate set to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see `glInterleavedArrays'.) If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a texture coordinate array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as texture coordinate vertex array client-side state (`GL_TEXTURE_COORD_ARRAY_BUFFER_BINDING'). When a texture coordinate array is specified, SIZE, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable a texture coordinate array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_TEXTURE_COORD_ARRAY'. If enabled, the texture coordinate array is used when `glArrayElement', `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', or `glDrawRangeElements' is called. `GL_INVALID_VALUE' is generated if SIZE is not 1, 2, 3, or 4. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glTexCoord1i (s GLint) -> void) (glTexCoord1f (s GLfloat) -> void) (glTexCoord2i (s GLint) (t GLint) -> void) (glTexCoord2f (s GLfloat) (t GLfloat) -> void) (glTexCoord3i (s GLint) (t GLint) (r GLint) -> void) (glTexCoord3f (s GLfloat) (t GLfloat) (r GLfloat) -> void) (glTexCoord4i (s GLint) (t GLint) (r GLint) (q GLint) -> void) (glTexCoord4f (s GLfloat) (t GLfloat) (r GLfloat) (q GLfloat) -> void)) "Set the current texture coordinates. S T R Q Specify S, T, R, and Q texture coordinates. Not all parameters are present in all forms of the command. `glTexCoord' specifies texture coordinates in one, two, three, or four dimensions. `glTexCoord1' sets the current texture coordinates to (S,001) ; a call to `glTexCoord2' sets them to (S,T01) . Similarly, `glTexCoord3' specifies the texture coordinates as (S,TR1) , and `glTexCoord4' defines all four components explicitly as (S,TRQ) . The current texture coordinates are part of the data that is associated with each vertex and with the current raster position. Initially, the values for S, T, R, and Q are (0, 0, 0, 1).") (define-gl-procedures ((glTexEnvf (target GLenum) (pname GLenum) (param GLfloat) -> void) (glTexEnvi (target GLenum) (pname GLenum) (param GLint) -> void)) "Set texture environment parameters. TARGET Specifies a texture environment. May be `GL_TEXTURE_ENV', `GL_TEXTURE_FILTER_CONTROL' or `GL_POINT_SPRITE'. PNAME Specifies the symbolic name of a single-valued texture environment parameter. May be either `GL_TEXTURE_ENV_MODE', `GL_TEXTURE_LOD_BIAS', `GL_COMBINE_RGB', `GL_COMBINE_ALPHA', `GL_SRC0_RGB', `GL_SRC1_RGB', `GL_SRC2_RGB', `GL_SRC0_ALPHA', `GL_SRC1_ALPHA', `GL_SRC2_ALPHA', `GL_OPERAND0_RGB', `GL_OPERAND1_RGB', `GL_OPERAND2_RGB', `GL_OPERAND0_ALPHA', `GL_OPERAND1_ALPHA', `GL_OPERAND2_ALPHA', `GL_RGB_SCALE', `GL_ALPHA_SCALE', or `GL_COORD_REPLACE'. PARAM Specifies a single symbolic constant, one of `GL_ADD', `GL_ADD_SIGNED', `GL_INTERPOLATE', `GL_MODULATE', `GL_DECAL', `GL_BLEND', `GL_REPLACE', `GL_SUBTRACT', `GL_COMBINE', `GL_TEXTURE', `GL_CONSTANT', `GL_PRIMARY_COLOR', `GL_PREVIOUS', `GL_SRC_COLOR', `GL_ONE_MINUS_SRC_COLOR', `GL_SRC_ALPHA', `GL_ONE_MINUS_SRC_ALPHA', a single boolean value for the point sprite texture coordinate replacement, a single floating-point value for the texture level-of-detail bias, or 1.0, 2.0, or 4.0 when specifying the `GL_RGB_SCALE' or `GL_ALPHA_SCALE'. A texture environment specifies how texture values are interpreted when a fragment is textured. When TARGET is `GL_TEXTURE_FILTER_CONTROL', PNAME must be `GL_TEXTURE_LOD_BIAS'. When TARGET is `GL_TEXTURE_ENV', PNAME can be `GL_TEXTURE_ENV_MODE', `GL_TEXTURE_ENV_COLOR', `GL_COMBINE_RGB', `GL_COMBINE_ALPHA', `GL_RGB_SCALE', `GL_ALPHA_SCALE', `GL_SRC0_RGB', `GL_SRC1_RGB', `GL_SRC2_RGB', `GL_SRC0_ALPHA', `GL_SRC1_ALPHA', or `GL_SRC2_ALPHA'. If PNAME is `GL_TEXTURE_ENV_MODE', then PARAMS is (or points to) the symbolic name of a texture function. Six texture functions may be specified: `GL_ADD', `GL_MODULATE', `GL_DECAL', `GL_BLEND', `GL_REPLACE', or `GL_COMBINE'. The following table shows the correspondence of filtered texture values R_T , G_T , B_T , A_T , L_T , I_T to texture source components. C_S and A_S are used by the texture functions described below. Texture Base Internal Format `C'_S , `A'_S `GL_ALPHA' (0, 0, 0) , A_T `GL_LUMINANCE' ( L_T , L_T , L_T ) , 1 `GL_LUMINANCE_ALPHA' ( L_T , L_T , L_T ) , A_T `GL_INTENSITY' ( I_T , I_T , I_T ) , I_T `GL_RGB' ( R_T , G_T , B_T ) , 1 `GL_RGBA' ( R_T , G_T , B_T ) , A_T A texture function acts on the fragment to be textured using the texture image value that applies to the fragment (see `glTexParameter') and produces an RGBA color for that fragment. The following table shows how the RGBA color is produced for each of the first five texture functions that can be chosen. C is a triple of color values (RGB) and A is the associated alpha value. RGBA values extracted from a texture image are in the range [0,1]. The subscript P refers to the color computed from the previous texture stage (or the incoming fragment if processing texture stage 0), the subscript S to the texture source color, the subscript C to the texture environment color, and the subscript V indicates a value produced by the texture function. Texture Base Internal Format `Value', `GL_REPLACE' Function , `GL_MODULATE' Function , `GL_DECAL' Function , `GL_BLEND' Function , `GL_ADD' Function `GL_ALPHA' C_V= , C_P , C_P , undefined , C_P , C_P A_V= , A_S , A_P\u2062A_S , , A_V=A_P\u2062A_S , A_P\u2062A_S `GL_LUMINANCE' C_V= , C_S , C_P\u2062C_S , undefined , C_P\u2062(1-C_S,)+C_C\u2062C_S , C_P+C_S (or 1) A_V= , A_P , A_P , , A_P , A_P `GL_LUMINANCE_ALPHA' C_V= , C_S , C_P\u2062C_S , undefined , C_P\u2062(1-C_S,)+C_C\u2062C_S , C_P+C_S (or 2) A_V= , A_S , A_P\u2062A_S , , A_P\u2062A_S , A_P\u2062A_S `GL_INTENSITY' C_V= , C_S , C_P\u2062C_S , undefined , C_P\u2062(1-C_S,)+C_C\u2062C_S , C_P+C_S A_V= , A_S , A_P\u2062A_S , , A_P\u2062(1-A_S,)+A_C\u2062A_S , A_P+A_S `GL_RGB' C_V= , C_S , C_P\u2062C_S , C_S , C_P\u2062(1-C_S,)+C_C\u2062C_S , C_P+C_S (or 3) A_V= , A_P , A_P , A_P , A_P , A_P `GL_RGBA' C_V= , C_S , C_P\u2062C_S , C_P\u2062(1-A_S,)+C_S\u2062A_S , C_P\u2062(1-C_S,)+C_C\u2062C_S , C_P+C_S (or 4) A_V= , A_S , A_P\u2062A_S , A_P , A_P\u2062A_S , A_P\u2062A_S If PNAME is `GL_TEXTURE_ENV_MODE', and PARAMS is `GL_COMBINE', the form of the texture function depends on the values of `GL_COMBINE_RGB' and `GL_COMBINE_ALPHA'. The following describes how the texture sources, as specified by `GL_SRC0_RGB', `GL_SRC1_RGB', `GL_SRC2_RGB', `GL_SRC0_ALPHA', `GL_SRC1_ALPHA', and `GL_SRC2_ALPHA', are combined to produce a final texture color. In the following tables, `GL_SRC0_c' is represented by ARG0 , `GL_SRC1_c' is represented by ARG1 , and `GL_SRC2_c' is represented by ARG2 . `GL_COMBINE_RGB' accepts any of `GL_REPLACE', `GL_MODULATE', `GL_ADD', `GL_ADD_SIGNED', `GL_INTERPOLATE', `GL_SUBTRACT', `GL_DOT3_RGB', or `GL_DOT3_RGBA'. *`GL_COMBINE_RGB'* *Texture Function* `GL_REPLACE' ARG0 `GL_MODULATE' ARG0×ARG1 `GL_ADD' ARG0+ARG1 `GL_ADD_SIGNED' ARG0+ARG1-0.5 `GL_INTERPOLATE' ARG0×ARG2+ARG1×(1-ARG2,) `GL_SUBTRACT' ARG0-ARG1 `GL_DOT3_RGB' or `GL_DOT3_RGBA' 4×(((ARG0_R,-0.5,)×(ARG1_R,-0.5,),)+((ARG0_G,-0.5,)×(ARG1_G,-0.5,), )+((ARG0_B,-0.5,)×(ARG1_B,-0.5,),),) The scalar results for `GL_DOT3_RGB' and `GL_DOT3_RGBA' are placed into each of the 3 (RGB) or 4 (RGBA) components on output. Likewise, `GL_COMBINE_ALPHA' accepts any of `GL_REPLACE', `GL_MODULATE', `GL_ADD', `GL_ADD_SIGNED', `GL_INTERPOLATE', or `GL_SUBTRACT'. The following table describes how alpha values are combined: *`GL_COMBINE_ALPHA'* *Texture Function* `GL_REPLACE' ARG0 `GL_MODULATE' ARG0×ARG1 `GL_ADD' ARG0+ARG1 `GL_ADD_SIGNED' ARG0+ARG1-0.5 `GL_INTERPOLATE' ARG0×ARG2+ARG1×(1-ARG2,) `GL_SUBTRACT' ARG0-ARG1 In the following tables, the value C_S represents the color sampled from the currently bound texture, C_C represents the constant texture-environment color, C_F represents the primary color of the incoming fragment, and C_P represents the color computed from the previous texture stage or C_F if processing texture stage 0. Likewise, A_S , A_C , A_F , and A_P represent the respective alpha values. The following table describes the values assigned to ARG0 , ARG1 , and ARG2 based upon the RGB sources and operands: *`GL_SRCn_RGB'* *`GL_OPERANDn_RGB'*, *Argument Value* `GL_TEXTURE' `GL_SRC_COLOR', C_S, `GL_ONE_MINUS_SRC_COLOR', 1-C_S, `GL_SRC_ALPHA', A_S, `GL_ONE_MINUS_SRC_ALPHA', 1-A_S, `GL_TEXTUREn' `GL_SRC_COLOR', C_S, `GL_ONE_MINUS_SRC_COLOR', 1-C_S, `GL_SRC_ALPHA', A_S, `GL_ONE_MINUS_SRC_ALPHA', 1-A_S, `GL_CONSTANT' `GL_SRC_COLOR', C_C, `GL_ONE_MINUS_SRC_COLOR', 1-C_C, `GL_SRC_ALPHA', A_C, `GL_ONE_MINUS_SRC_ALPHA', 1-A_C, `GL_PRIMARY_COLOR' `GL_SRC_COLOR', C_F, `GL_ONE_MINUS_SRC_COLOR', 1-C_F, `GL_SRC_ALPHA', A_F, `GL_ONE_MINUS_SRC_ALPHA', 1-A_F, `GL_PREVIOUS' `GL_SRC_COLOR', C_P, `GL_ONE_MINUS_SRC_COLOR', 1-C_P, `GL_SRC_ALPHA', A_P, `GL_ONE_MINUS_SRC_ALPHA', 1-A_P, For `GL_TEXTUREn' sources, C_S and A_S represent the color and alpha, respectively, produced from texture stage N . The follow table describes the values assigned to ARG0 , ARG1 , and ARG2 based upon the alpha sources and operands: *`GL_SRCn_ALPHA'* *`GL_OPERANDn_ALPHA'*, *Argument Value* `GL_TEXTURE' `GL_SRC_ALPHA', A_S, `GL_ONE_MINUS_SRC_ALPHA', 1-A_S, `GL_TEXTUREn' `GL_SRC_ALPHA', A_S, `GL_ONE_MINUS_SRC_ALPHA', 1-A_S, `GL_CONSTANT' `GL_SRC_ALPHA', A_C, `GL_ONE_MINUS_SRC_ALPHA', 1-A_C, `GL_PRIMARY_COLOR' `GL_SRC_ALPHA', A_F, `GL_ONE_MINUS_SRC_ALPHA', 1-A_F, `GL_PREVIOUS' `GL_SRC_ALPHA', A_P, `GL_ONE_MINUS_SRC_ALPHA', 1-A_P, The RGB and alpha results of the texture function are multipled by the values of `GL_RGB_SCALE' and `GL_ALPHA_SCALE', respectively, and clamped to the range [0,1] . If PNAME is `GL_TEXTURE_ENV_COLOR', PARAMS is a pointer to an array that holds an RGBA color consisting of four values. Integer color components are interpreted linearly such that the most positive integer maps to 1.0, and the most negative integer maps to -1.0. The values are clamped to the range [0,1] when they are specified. C_C takes these four values. If PNAME is `GL_TEXTURE_LOD_BIAS', the value specified is added to the texture level-of-detail parameter, that selects which mipmap, or mipmaps depending upon the selected `GL_TEXTURE_MIN_FILTER', will be sampled. `GL_TEXTURE_ENV_MODE' defaults to `GL_MODULATE' and `GL_TEXTURE_ENV_COLOR' defaults to (0, 0, 0, 0). If TARGET is `GL_POINT_SPRITE' and PNAME is `GL_COORD_REPLACE', the boolean value specified is used to either enable or disable point sprite texture coordinate replacement. The default value is `GL_FALSE'. `GL_INVALID_ENUM' is generated when TARGET or PNAME is not one of the accepted defined values, or when PARAMS should have a defined constant value (based on the value of PNAME) and does not. `GL_INVALID_VALUE' is generated if the PARAMS value for `GL_RGB_SCALE' or `GL_ALPHA_SCALE' are not one of 1.0, 2.0, or 4.0. `GL_INVALID_OPERATION' is generated if `glTexEnv' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexGeni (coord GLenum) (pname GLenum) (param GLint) -> void) (glTexGenf (coord GLenum) (pname GLenum) (param GLfloat) -> void)) "Control the generation of texture coordinates. COORD Specifies a texture coordinate. Must be one of `GL_S', `GL_T', `GL_R', or `GL_Q'. PNAME Specifies the symbolic name of the texture-coordinate generation function. Must be `GL_TEXTURE_GEN_MODE'. PARAM Specifies a single-valued texture generation parameter, one of `GL_OBJECT_LINEAR', `GL_EYE_LINEAR', `GL_SPHERE_MAP', `GL_NORMAL_MAP', or `GL_REFLECTION_MAP'. `glTexGen' selects a texture-coordinate generation function or supplies coefficients for one of the functions. COORD names one of the (S, T, R, Q) texture coordinates; it must be one of the symbols `GL_S', `GL_T', `GL_R', or `GL_Q'. PNAME must be one of three symbolic constants: `GL_TEXTURE_GEN_MODE', `GL_OBJECT_PLANE', or `GL_EYE_PLANE'. If PNAME is `GL_TEXTURE_GEN_MODE', then PARAMS chooses a mode, one of `GL_OBJECT_LINEAR', `GL_EYE_LINEAR', `GL_SPHERE_MAP', `GL_NORMAL_MAP', or `GL_REFLECTION_MAP'. If PNAME is either `GL_OBJECT_PLANE' or `GL_EYE_PLANE', PARAMS contains coefficients for the corresponding texture generation function. If the texture generation function is `GL_OBJECT_LINEAR', the function G=P_1×X_O+P_2×Y_O+P_3×Z_O+P_4×W_O is used, where G is the value computed for the coordinate named in COORD, P_1 , P_2 , P_3 , and P_4 are the four values supplied in PARAMS, and X_O , Y_O , Z_O , and W_O are the object coordinates of the vertex. This function can be used, for example, to texture-map terrain using sea level as a reference plane (defined by P_1 , P_2 , P_3 , and P_4 ). The altitude of a terrain vertex is computed by the `GL_OBJECT_LINEAR' coordinate generation function as its distance from sea level; that altitude can then be used to index the texture image to map white snow onto peaks and green grass onto foothills. If the texture generation function is `GL_EYE_LINEAR', the function G=P_1,^″×X_E+P_2,^″×Y_E+P_3,^″×Z_E+P_4,^″×W_E is used, where (P_1,^″\u2062P_2,^″\u2062P_3,^″\u2062P_4,^″,)=(P_1\u2062P_2\u2062P_3\u2062P_4,)\u2062M^-1 and X_E , Y_E , Z_E , and W_E are the eye coordinates of the vertex, P_1 , P_2 , P_3 , and P_4 are the values supplied in PARAMS, and M is the modelview matrix when `glTexGen' is invoked. If M is poorly conditioned or singular, texture coordinates generated by the resulting function may be inaccurate or undefined. Note that the values in PARAMS define a reference plane in eye coordinates. The modelview matrix that is applied to them may not be the same one in effect when the polygon vertices are transformed. This function establishes a field of texture coordinates that can produce dynamic contour lines on moving objects. If the texture generation function is `GL_SPHERE_MAP' and COORD is either `GL_S' or `GL_T', S and T texture coordinates are generated as follows. Let U be the unit vector pointing from the origin to the polygon vertex (in eye coordinates). Let N sup prime be the current normal, after transformation to eye coordinates. Let F=(F_X\u2062F_Y\u2062F_Z,)^T be the reflection vector such that F=U-2\u2062N^″\u2062N^″,^T\u2062U Finally, let M=2\u2062√(F_X,^2+F_Y,^2+(F_Z+1,)^2,) . Then the values assigned to the S and T texture coordinates are S=F_X/M+1/2 T=F_Y/M+1/2 To enable or disable a texture-coordinate generation function, call `glEnable' or `glDisable' with one of the symbolic texture-coordinate names (`GL_TEXTURE_GEN_S', `GL_TEXTURE_GEN_T', `GL_TEXTURE_GEN_R', or `GL_TEXTURE_GEN_Q') as the argument. When enabled, the specified texture coordinate is computed according to the generating function associated with that coordinate. When disabled, subsequent vertices take the specified texture coordinate from the current set of texture coordinates. Initially, all texture generation functions are set to `GL_EYE_LINEAR' and are disabled. Both S plane equations are (1, 0, 0, 0), both T plane equations are (0, 1, 0, 0), and all R and Q plane equations are (0, 0, 0, 0). When the `ARB_multitexture' extension is supported, `glTexGen' sets the texture generation parameters for the currently active texture unit, selected with `glActiveTexture'. `GL_INVALID_ENUM' is generated when COORD or PNAME is not an accepted defined value, or when PNAME is `GL_TEXTURE_GEN_MODE' and PARAMS is not an accepted defined value. `GL_INVALID_ENUM' is generated when PNAME is `GL_TEXTURE_GEN_MODE', PARAMS is `GL_SPHERE_MAP', and COORD is either `GL_R' or `GL_Q'. `GL_INVALID_OPERATION' is generated if `glTexGen' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexImage1D (target GLenum) (level GLint) (internalFormat GLint) (width GLsizei) (border GLint) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a one-dimensional texture image. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D' or `GL_PROXY_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the number of color components in the texture. Must be 1, 2, 3, or 4, or one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', `GL_DEPTH_COMPONENT32', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', `GL_RGBA16', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', `GL_SLUMINANCE8_ALPHA8', `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', or `GL_SRGB8_ALPHA8'. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support texture images that are at least 64 texels wide. The height of the 1D texture image is 1. BORDER Specifies the width of the border. Must be either 0 or 1. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable one-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_1D'. Texture images are defined with `glTexImage1D'. The arguments describe the parameters of the texture image, such as width, width of the border, level-of-detail number (see `glTexParameter'), and the internal resolution and format used to store the image. The last three arguments describe how the image is represented in memory; they are identical to the pixel formats used for `glDrawPixels'. If TARGET is `GL_PROXY_TEXTURE_1D', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. If TARGET is `GL_TEXTURE_1D', data is read from DATA as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on TYPE. These values are grouped into sets of one, two, three, or four values, depending on FORMAT, to form elements. If TYPE is `GL_BITMAP', the data is considered as a string of unsigned bytes (and FORMAT must be `GL_COLOR_INDEX'). Each data byte is treated as eight 1-bit elements, with bit ordering determined by `GL_UNPACK_LSB_FIRST' (see `glPixelStore'). If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. The first element corresponds to the left end of the texture array. Subsequent elements progress left-to-right through the remaining texels in the texture array. The final element corresponds to the right end of the texture array. FORMAT determines the composition of each element in DATA. It can assume one of these symbolic values: `GL_COLOR_INDEX' Each element is a single value, a color index. The GL converts it to fixed point (with an unspecified number of zero bits to the right of the binary point), shifted left or right depending on the value and sign of `GL_INDEX_SHIFT', and added to `GL_INDEX_OFFSET' (see `glPixelTransfer'). The resulting index is converted to a set of color components using the `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', and `GL_PIXEL_MAP_I_TO_A' tables, and clamped to the range [0,1]. `GL_RED' Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_GREEN' Each element is a single green component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_BLUE' Each element is a single blue component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and green, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_ALPHA' Each element is a single alpha component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_INTENSITY' Each element is a single intensity value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the intensity value three times for red, green, blue, and alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGB' `GL_BGR' Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGBA' `GL_BGRA' Each element contains all four components. Each component is multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE' Each element is a single luminance value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue and attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE_ALPHA' Each element is a luminance/alpha pair. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_DEPTH_COMPONENT' Each element is a single depth value. The GL converts it to floating point, multiplies by the signed scale factor `GL_DEPTH_SCALE', adds the signed bias `GL_DEPTH_BIAS', and clamps to the range [0,1] (see `glPixelTransfer'). Refer to the `glDrawPixels' reference page for a description of the acceptable values for the TYPE parameter. If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with INTERNALFORMAT. The GL will choose an internal representation that closely approximates that requested by INTERNALFORMAT, but it may not match exactly. (The representations specified by `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', and `GL_RGBA' must match exactly. The numeric values 1, 2, 3, and 4 may also be used to specify the above representations.) If the INTERNALFORMAT parameter is one of the generic compressed formats, `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA', the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format. If the INTERNALFORMAT parameter is `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', `GL_SRGB8_ALPHA8', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', or `GL_SLUMINANCE8_ALPHA8', the texture is treated as if the red, green, blue, or luminance components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component C_S to a linear component C_L is: C_L={(C_S/12.92 if C_S≤0.04045), ((`c'_`s'+0.055/1.055)^2.4 if C_S>0.04045) Assume C_S is the sRGB component in the range [0,1]. Use the `GL_PROXY_TEXTURE_1D' target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call `glGetTexLevelParameter'. If the texture cannot be accommodated, texture state is set to 0. A one-component texture image uses only the red component of the RGBA color from DATA. A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components. Depth textures can be treated as LUMINANCE, INTENSITY or ALPHA textures during texture filtering and application.\xa0Image-based shadowing\xa0can\xa0be \xa0enabled\xa0by\xa0comparing texture r coordinates to depth texture values to generate a boolean result. See `glTexParameter' for details on texture comparison. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_1D' or `GL_PROXY_TEXTURE_1D'. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted format constant. Format constants other than `GL_STENCIL_INDEX' are accepted. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not 1, 2, 3, 4, or one of the accepted resolution and format symbolic constants. `GL_INVALID_VALUE' is generated if WIDTH is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if non-power-of-two textures are not supported and the WIDTH cannot be represented as 2^N+2\u2061(BORDER,) for some integer value of N. `GL_INVALID_VALUE' is generated if BORDER is not 0 or 1. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if FORMAT is `GL_DEPTH_COMPONENT' and INTERNALFORMAT is not `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32'. `GL_INVALID_OPERATION' is generated if INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32', and FORMAT is not `GL_DEPTH_COMPONENT'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexImage1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexImage2D (target GLenum) (level GLint) (internalFormat GLint) (width GLsizei) (height GLsizei) (border GLint) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a two-dimensional texture image. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_PROXY_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z', or `GL_PROXY_TEXTURE_CUBE_MAP'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. INTERNALFORMAT Specifies the number of color components in the texture. Must be 1, 2, 3, or 4, or one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', `GL_DEPTH_COMPONENT32', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', `GL_RGBA16', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', `GL_SLUMINANCE8_ALPHA8', `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', or `GL_SRGB8_ALPHA8'. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support texture images that are at least 64 texels wide. HEIGHT Specifies the height of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^M+2\u2061(BORDER,) for some integer M . All implementations support texture images that are at least 64 texels high. BORDER Specifies the width of the border. Must be either 0 or 1. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_2D'. To enable and disable texturing using cube-mapped texture, call `glEnable' and `glDisable' with argument `GL_TEXTURE_CUBE_MAP'. To define texture images, call `glTexImage2D'. The arguments describe the parameters of the texture image, such as height, width, width of the border, level-of-detail number (see `glTexParameter'), and number of color components provided. The last three arguments describe how the image is represented in memory; they are identical to the pixel formats used for `glDrawPixels'. If TARGET is `GL_PROXY_TEXTURE_2D' or `GL_PROXY_TEXTURE_CUBE_MAP', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. If TARGET is `GL_TEXTURE_2D', or one of the `GL_TEXTURE_CUBE_MAP' targets, data is read from DATA as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on TYPE. These values are grouped into sets of one, two, three, or four values, depending on FORMAT, to form elements. If TYPE is `GL_BITMAP', the data is considered as a string of unsigned bytes (and FORMAT must be `GL_COLOR_INDEX'). Each data byte is treated as eight 1-bit elements, with bit ordering determined by `GL_UNPACK_LSB_FIRST' (see `glPixelStore'). If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. The first element corresponds to the lower left corner of the texture image. Subsequent elements progress left-to-right through the remaining texels in the lowest row of the texture image, and then in successively higher rows of the texture image. The final element corresponds to the upper right corner of the texture image. FORMAT determines the composition of each element in DATA. It can assume one of these symbolic values: `GL_COLOR_INDEX' Each element is a single value, a color index. The GL converts it to fixed point (with an unspecified number of zero bits to the right of the binary point), shifted left or right depending on the value and sign of `GL_INDEX_SHIFT', and added to `GL_INDEX_OFFSET' (see `glPixelTransfer'). The resulting index is converted to a set of color components using the `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', and `GL_PIXEL_MAP_I_TO_A' tables, and clamped to the range [0,1]. `GL_RED' Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_GREEN' Each element is a single green component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_BLUE' Each element is a single blue component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and green, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_ALPHA' Each element is a single alpha component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_INTENSITY' Each element is a single intensity value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the intensity value three times for red, green, blue, and alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGB' `GL_BGR' Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGBA' `GL_BGRA' Each element contains all four components. Each component is multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE' Each element is a single luminance value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue and attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE_ALPHA' Each element is a luminance/alpha pair. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_DEPTH_COMPONENT' Each element is a single depth value. The GL converts it to floating point, multiplies by the signed scale factor `GL_DEPTH_SCALE', adds the signed bias `GL_DEPTH_BIAS', and clamps to the range [0,1] (see `glPixelTransfer'). Refer to the `glDrawPixels' reference page for a description of the acceptable values for the TYPE parameter. If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with INTERNALFORMAT. The GL will choose an internal representation that closely approximates that requested by INTERNALFORMAT, but it may not match exactly. (The representations specified by `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', and `GL_RGBA' must match exactly. The numeric values 1, 2, 3, and 4 may also be used to specify the above representations.) If the INTERNALFORMAT parameter is one of the generic compressed formats, `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA', the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format. If the INTERNALFORMAT parameter is `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', `GL_SRGB8_ALPHA8', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', or `GL_SLUMINANCE8_ALPHA8', the texture is treated as if the red, green, blue, or luminance components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component C_S to a linear component C_L is: C_L={(C_S/12.92 if C_S≤0.04045), ((`c'_`s'+0.055/1.055)^2.4 if C_S>0.04045) Assume C_S is the sRGB component in the range [0,1]. Use the `GL_PROXY_TEXTURE_2D' or `GL_PROXY_TEXTURE_CUBE_MAP' target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call `glGetTexLevelParameter'. If the texture cannot be accommodated, texture state is set to 0. A one-component texture image uses only the red component of the RGBA color extracted from DATA. A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components. Depth textures can be treated as LUMINANCE, INTENSITY or ALPHA textures during texture filtering and application.\xa0Image-based shadowing\xa0can\xa0be \xa0enabled\xa0by\xa0comparing texture r coordinates to depth texture values to generate a boolean result. See `glTexParameter' for details on texture comparison. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_2D', `GL_PROXY_TEXTURE_2D', `GL_PROXY_TEXTURE_CUBE_MAP', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. `GL_INVALID_ENUM' is generated if TARGET is one of the six cube map 2D image targets and the width and height parameters are not equal. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if WIDTH or HEIGHT is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not 1, 2, 3, 4, or one of the accepted resolution and format symbolic constants. `GL_INVALID_VALUE' is generated if WIDTH or HEIGHT is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if non-power-of-two textures are not supported and the WIDTH or HEIGHT cannot be represented as 2^K+2\u2061(BORDER,) for some integer value of K. `GL_INVALID_VALUE' is generated if BORDER is not 0 or 1. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if TARGET is not `GL_TEXTURE_2D' or `GL_PROXY_TEXTURE_2D' and INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32'. `GL_INVALID_OPERATION' is generated if FORMAT is `GL_DEPTH_COMPONENT' and INTERNALFORMAT is not `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32'. `GL_INVALID_OPERATION' is generated if INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32', and FORMAT is not `GL_DEPTH_COMPONENT'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexImage3D (target GLenum) (level GLint) (internalFormat GLint) (width GLsizei) (height GLsizei) (depth GLsizei) (border GLint) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a three-dimensional texture image. TARGET Specifies the target texture. Must be `GL_TEXTURE_3D' or `GL_PROXY_TEXTURE_3D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the N^TH mipmap reduction image. INTERNALFORMAT Specifies the number of color components in the texture. Must be 1, 2, 3, or 4, or one of the following symbolic constants: `GL_ALPHA', `GL_ALPHA4', `GL_ALPHA8', `GL_ALPHA12', `GL_ALPHA16', `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_RGB', `GL_COMPRESSED_RGBA', `GL_LUMINANCE', `GL_LUMINANCE4', `GL_LUMINANCE8', `GL_LUMINANCE12', `GL_LUMINANCE16', `GL_LUMINANCE_ALPHA', `GL_LUMINANCE4_ALPHA4', `GL_LUMINANCE6_ALPHA2', `GL_LUMINANCE8_ALPHA8', `GL_LUMINANCE12_ALPHA4', `GL_LUMINANCE12_ALPHA12', `GL_LUMINANCE16_ALPHA16', `GL_INTENSITY', `GL_INTENSITY4', `GL_INTENSITY8', `GL_INTENSITY12', `GL_INTENSITY16', `GL_R3_G3_B2', `GL_RGB', `GL_RGB4', `GL_RGB5', `GL_RGB8', `GL_RGB10', `GL_RGB12', `GL_RGB16', `GL_RGBA', `GL_RGBA2', `GL_RGBA4', `GL_RGB5_A1', `GL_RGBA8', `GL_RGB10_A2', `GL_RGBA12', `GL_RGBA16', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', `GL_SLUMINANCE8_ALPHA8', `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', or `GL_SRGB8_ALPHA8'. WIDTH Specifies the width of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^N+2\u2061(BORDER,) for some integer N . All implementations support 3D texture images that are at least 16 texels wide. HEIGHT Specifies the height of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^M+2\u2061(BORDER,) for some integer M . All implementations support 3D texture images that are at least 16 texels high. DEPTH Specifies the depth of the texture image including the border if any. If the GL version does not support non-power-of-two sizes, this value must be 2^K+2\u2061(BORDER,) for some integer K . All implementations support 3D texture images that are at least 16 texels deep. BORDER Specifies the width of the border. Must be either 0 or 1. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable three-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_3D'. To define texture images, call `glTexImage3D'. The arguments describe the parameters of the texture image, such as height, width, depth, width of the border, level-of-detail number (see `glTexParameter'), and number of color components provided. The last three arguments describe how the image is represented in memory; they are identical to the pixel formats used for `glDrawPixels'. If TARGET is `GL_PROXY_TEXTURE_3D', no data is read from DATA, but all of the texture image state is recalculated, checked for consistency, and checked against the implementation's capabilities. If the implementation cannot handle a texture of the requested texture size, it sets all of the image state to 0, but does not generate an error (see `glGetError'). To query for an entire mipmap array, use an image array level greater than or equal to 1. If TARGET is `GL_TEXTURE_3D', data is read from DATA as a sequence of signed or unsigned bytes, shorts, or longs, or single-precision floating-point values, depending on TYPE. These values are grouped into sets of one, two, three, or four values, depending on FORMAT, to form elements. If TYPE is `GL_BITMAP', the data is considered as a string of unsigned bytes (and FORMAT must be `GL_COLOR_INDEX'). Each data byte is treated as eight 1-bit elements, with bit ordering determined by `GL_UNPACK_LSB_FIRST' (see `glPixelStore'). If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. The first element corresponds to the lower left corner of the texture image. Subsequent elements progress left-to-right through the remaining texels in the lowest row of the texture image, and then in successively higher rows of the texture image. The final element corresponds to the upper right corner of the texture image. FORMAT determines the composition of each element in DATA. It can assume one of these symbolic values: `GL_COLOR_INDEX' Each element is a single value, a color index. The GL converts it to fixed point (with an unspecified number of zero bits to the right of the binary point), shifted left or right depending on the value and sign of `GL_INDEX_SHIFT', and added to `GL_INDEX_OFFSET' (see `glPixelTransfer'). The resulting index is converted to a set of color components using the `GL_PIXEL_MAP_I_TO_R', `GL_PIXEL_MAP_I_TO_G', `GL_PIXEL_MAP_I_TO_B', and `GL_PIXEL_MAP_I_TO_A' tables, and clamped to the range [0,1]. `GL_RED' Each element is a single red component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for green and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_GREEN' Each element is a single green component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and blue, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_BLUE' Each element is a single blue component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red and green, and 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_ALPHA' Each element is a single alpha component. The GL converts it to floating point and assembles it into an RGBA element by attaching 0 for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_INTENSITY' Each element is a single intensity value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the intensity value three times for red, green, blue, and alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGB' `GL_BGR' Each element is an RGB triple. The GL converts it to floating point and assembles it into an RGBA element by attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_RGBA' `GL_BGRA' Each element contains all four components. Each component is multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE' Each element is a single luminance value. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue and attaching 1 for alpha. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). `GL_LUMINANCE_ALPHA' Each element is a luminance/alpha pair. The GL converts it to floating point, then assembles it into an RGBA element by replicating the luminance value three times for red, green, and blue. Each component is then multiplied by the signed scale factor `GL_c_SCALE', added to the signed bias `GL_c_BIAS', and clamped to the range [0,1] (see `glPixelTransfer'). Refer to the `glDrawPixels' reference page for a description of the acceptable values for the TYPE parameter. If an application wants to store the texture at a certain resolution or in a certain format, it can request the resolution and format with INTERNALFORMAT. The GL will choose an internal representation that closely approximates that requested by INTERNALFORMAT, but it may not match exactly. (The representations specified by `GL_LUMINANCE', `GL_LUMINANCE_ALPHA', `GL_RGB', and `GL_RGBA' must match exactly. The numeric values 1, 2, 3, and 4 may also be used to specify the above representations.) If the INTERNALFORMAT parameter is one of the generic compressed formats, `GL_COMPRESSED_ALPHA', `GL_COMPRESSED_INTENSITY', `GL_COMPRESSED_LUMINANCE', `GL_COMPRESSED_LUMINANCE_ALPHA', `GL_COMPRESSED_RGB', or `GL_COMPRESSED_RGBA', the GL will replace the internal format with the symbolic constant for a specific internal format and compress the texture before storage. If no corresponding internal format is available, or the GL can not compress that image for any reason, the internal format is instead replaced with a corresponding base internal format. If the INTERNALFORMAT parameter is `GL_SRGB', `GL_SRGB8', `GL_SRGB_ALPHA', `GL_SRGB8_ALPHA8', `GL_SLUMINANCE', `GL_SLUMINANCE8', `GL_SLUMINANCE_ALPHA', or `GL_SLUMINANCE8_ALPHA8', the texture is treated as if the red, green, blue, or luminance components are encoded in the sRGB color space. Any alpha component is left unchanged. The conversion from the sRGB encoded component C_S to a linear component C_L is: C_L={(C_S/12.92 if C_S≤0.04045), ((`c'_`s'+0.055/1.055)^2.4 if C_S>0.04045) Assume C_S is the sRGB component in the range [0,1]. Use the `GL_PROXY_TEXTURE_3D' target to try out a resolution and format. The implementation will update and recompute its best match for the requested storage resolution and format. To then query this state, call `glGetTexLevelParameter'. If the texture cannot be accommodated, texture state is set to 0. A one-component texture image uses only the red component of the RGBA color extracted from DATA. A two-component image uses the R and A values. A three-component image uses the R, G, and B values. A four-component image uses all of the RGBA components. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_3D' or `GL_PROXY_TEXTURE_3D'. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted format constant. Format constants other than `GL_STENCIL_INDEX' and `GL_DEPTH_COMPONENT' are accepted. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2\u2061(MAX,) , where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if INTERNALFORMAT is not 1, 2, 3, 4, or one of the accepted resolution and format symbolic constants. `GL_INVALID_VALUE' is generated if WIDTH, HEIGHT, or DEPTH is less than 0 or greater than 2 + `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if non-power-of-two textures are not supported and the WIDTH, HEIGHT, or DEPTH cannot be represented as 2^K+2\u2061(BORDER,) for some integer value of K. `GL_INVALID_VALUE' is generated if BORDER is not 0 or 1. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if FORMAT or INTERNALFORMAT is `GL_DEPTH_COMPONENT', `GL_DEPTH_COMPONENT16', `GL_DEPTH_COMPONENT24', or `GL_DEPTH_COMPONENT32'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexImage3D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexParameterf (target GLenum) (pname GLenum) (param GLfloat) -> void) (glTexParameteri (target GLenum) (pname GLenum) (param GLint) -> void)) "Set texture parameters. TARGET Specifies the target texture, which must be either `GL_TEXTURE_1D', `GL_TEXTURE_2D', `GL_TEXTURE_3D', or `GL_TEXTURE_CUBE_MAP'. PNAME Specifies the symbolic name of a single-valued texture parameter. PNAME can be one of the following: `GL_TEXTURE_MIN_FILTER', `GL_TEXTURE_MAG_FILTER', `GL_TEXTURE_MIN_LOD', `GL_TEXTURE_MAX_LOD', `GL_TEXTURE_BASE_LEVEL', `GL_TEXTURE_MAX_LEVEL', `GL_TEXTURE_WRAP_S', `GL_TEXTURE_WRAP_T', `GL_TEXTURE_WRAP_R', `GL_TEXTURE_PRIORITY', `GL_TEXTURE_COMPARE_MODE', `GL_TEXTURE_COMPARE_FUNC', `GL_DEPTH_TEXTURE_MODE', or `GL_GENERATE_MIPMAP'. PARAM Specifies the value of PNAME. Texture mapping is a technique that applies an image onto an object's surface as if the image were a decal or cellophane shrink-wrap. The image is created in texture space, with an (S , T ) coordinate system. A texture is a one- or two-dimensional image and a set of parameters that determine how samples are derived from the image. `glTexParameter' assigns the value or values in PARAMS to the texture parameter specified as PNAME. TARGET defines the target texture, either `GL_TEXTURE_1D', `GL_TEXTURE_2D', or `GL_TEXTURE_3D'. The following symbols are accepted in PNAME: `GL_TEXTURE_MIN_FILTER' The texture minifying function is used whenever the pixel being textured maps to an area greater than one texture element. There are six defined minifying functions. Two of them use the nearest one or nearest four texture elements to compute the texture value. The other four use mipmaps. A mipmap is an ordered set of arrays representing the same image at progressively lower resolutions. If the texture has dimensions 2^N×2^M , there are MAX\u2061(N,M)+1 mipmaps. The first mipmap is the original texture, with dimensions 2^N×2^M . Each subsequent mipmap has dimensions 2^K-1,×2^L-1, , where 2^K×2^L are the dimensions of the previous mipmap, until either K=0 or L=0 . At that point, subsequent mipmaps have dimension 1×2^L-1, or 2^K-1,×1 until the final mipmap, which has dimension 1×1 . To define the mipmaps, call `glTexImage1D', `glTexImage2D', `glTexImage3D', `glCopyTexImage1D', or `glCopyTexImage2D' with the LEVEL argument indicating the order of the mipmaps. Level 0 is the original texture; level MAX\u2061(N,M) is the final 1×1 mipmap. PARAMS supplies a function for minifying the texture as one of the following: As more texture elements are sampled in the minification process, fewer aliasing artifacts will be apparent. While the `GL_NEAREST' and `GL_LINEAR' minification functions can be faster than the other four, they sample only one or four texture elements to determine the texture value of the pixel being rendered and can produce moire patterns or ragged transitions. The initial value of `GL_TEXTURE_MIN_FILTER' is `GL_NEAREST_MIPMAP_LINEAR'. `GL_TEXTURE_MAG_FILTER' The texture magnification function is used when the pixel being textured maps to an area less than or equal to one texture element. It sets the texture magnification function to either `GL_NEAREST' or `GL_LINEAR' (see below). `GL_NEAREST' is generally faster than `GL_LINEAR', but it can produce textured images with sharper edges because the transition between texture elements is not as smooth. The initial value of `GL_TEXTURE_MAG_FILTER' is `GL_LINEAR'. `GL_NEAREST' Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured. `GL_LINEAR' Returns the weighted average of the four texture elements that are closest to the center of the pixel being textured. These can include border texture elements, depending on the values of `GL_TEXTURE_WRAP_S' and `GL_TEXTURE_WRAP_T', and on the exact mapping. `GL_NEAREST_MIPMAP_NEAREST' Chooses the mipmap that most closely matches the size of the pixel being textured and uses the `GL_NEAREST' criterion (the texture element nearest to the center of the pixel) to produce a texture value. `GL_LINEAR_MIPMAP_NEAREST' Chooses the mipmap that most closely matches the size of the pixel being textured and uses the `GL_LINEAR' criterion (a weighted average of the four texture elements that are closest to the center of the pixel) to produce a texture value. `GL_NEAREST_MIPMAP_LINEAR' Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the `GL_NEAREST' criterion (the texture element nearest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values. `GL_LINEAR_MIPMAP_LINEAR' Chooses the two mipmaps that most closely match the size of the pixel being textured and uses the `GL_LINEAR' criterion (a weighted average of the four texture elements that are closest to the center of the pixel) to produce a texture value from each mipmap. The final texture value is a weighted average of those two values. `GL_NEAREST' Returns the value of the texture element that is nearest (in Manhattan distance) to the center of the pixel being textured. `GL_LINEAR' Returns the weighted average of the four texture elements that are closest to the center of the pixel being textured. These can include border texture elements, depending on the values of `GL_TEXTURE_WRAP_S' and `GL_TEXTURE_WRAP_T', and on the exact mapping. `GL_TEXTURE_MIN_LOD' Sets the minimum level-of-detail parameter. This floating-point value limits the selection of highest resolution mipmap (lowest mipmap level). The initial value is -1000. `GL_TEXTURE_MAX_LOD' Sets the maximum level-of-detail parameter. This floating-point value limits the selection of the lowest resolution mipmap (highest mipmap level). The initial value is 1000. `GL_TEXTURE_BASE_LEVEL' Specifies the index of the lowest defined mipmap level. This is an integer value. The initial value is 0. `GL_TEXTURE_MAX_LEVEL' Sets the index of the highest defined mipmap level. This is an integer value. The initial value is 1000. `GL_TEXTURE_WRAP_S' Sets the wrap parameter for texture coordinate S to either `GL_CLAMP', `GL_CLAMP_TO_BORDER', `GL_CLAMP_TO_EDGE', `GL_MIRRORED_REPEAT', or `GL_REPEAT'. `GL_CLAMP' causes S coordinates to be clamped to the range [0,1] and is useful for preventing wrapping artifacts when mapping a single image onto an object. `GL_CLAMP_TO_BORDER' causes the S coordinate to be clamped to the range [-1/2N,,1+1/2N,] , where N is the size of the texture in the direction of clamping.`GL_CLAMP_TO_EDGE' causes S coordinates to be clamped to the range [1/2N,,1-1/2N,] , where N is the size of the texture in the direction of clamping. `GL_REPEAT' causes the integer part of the S coordinate to be ignored; the GL uses only the fractional part, thereby creating a repeating pattern. `GL_MIRRORED_REPEAT' causes the S coordinate to be set to the fractional part of the texture coordinate if the integer part of S is even; if the integer part of S is odd, then the S texture coordinate is set to 1-FRAC\u2061(S,) , where FRAC\u2061(S,) represents the fractional part of S . Border texture elements are accessed only if wrapping is set to `GL_CLAMP' or `GL_CLAMP_TO_BORDER'. Initially, `GL_TEXTURE_WRAP_S' is set to `GL_REPEAT'. `GL_TEXTURE_WRAP_T' Sets the wrap parameter for texture coordinate T to either `GL_CLAMP', `GL_CLAMP_TO_BORDER', `GL_CLAMP_TO_EDGE', `GL_MIRRORED_REPEAT', or `GL_REPEAT'. See the discussion under `GL_TEXTURE_WRAP_S'. Initially, `GL_TEXTURE_WRAP_T' is set to `GL_REPEAT'. `GL_TEXTURE_WRAP_R' Sets the wrap parameter for texture coordinate R to either `GL_CLAMP', `GL_CLAMP_TO_BORDER', `GL_CLAMP_TO_EDGE', `GL_MIRRORED_REPEAT', or `GL_REPEAT'. See the discussion under `GL_TEXTURE_WRAP_S'. Initially, `GL_TEXTURE_WRAP_R' is set to `GL_REPEAT'. `GL_TEXTURE_BORDER_COLOR' Sets a border color. PARAMS contains four values that comprise the RGBA color of the texture border. Integer color components are interpreted linearly such that the most positive integer maps to 1.0, and the most negative integer maps to -1.0. The values are clamped to the range [0,1] when they are specified. Initially, the border color is (0, 0, 0, 0). `GL_TEXTURE_PRIORITY' Specifies the texture residence priority of the currently bound texture. Permissible values are in the range [0,1] . See `glPrioritizeTextures' and `glBindTexture' for more information. `GL_TEXTURE_COMPARE_MODE' Specifies the texture comparison mode for currently bound depth textures. That is, a texture whose internal format is `GL_DEPTH_COMPONENT_*'; see `glTexImage2D') Permissible values are: `GL_TEXTURE_COMPARE_FUNC' Specifies the comparison operator used when `GL_TEXTURE_COMPARE_MODE' is set to `GL_COMPARE_R_TO_TEXTURE'. Permissible values are: where R is the current interpolated texture coordinate, and D_T is the depth texture value sampled from the currently bound depth texture. RESULT is assigned to the either the luminance, intensity, or alpha (as specified by `GL_DEPTH_TEXTURE_MODE'.) `GL_DEPTH_TEXTURE_MODE' Specifies a single symbolic constant indicating how depth values should be treated during filtering and texture application. Accepted values are `GL_LUMINANCE', `GL_INTENSITY', and `GL_ALPHA'. The initial value is `GL_LUMINANCE'. `GL_GENERATE_MIPMAP' Specifies a boolean value that indicates if all levels of a mipmap array should be automatically updated when any modification to the base level mipmap is done. The initial value is `GL_FALSE'. `GL_COMPARE_R_TO_TEXTURE' Specifies that the interpolated and clamped R texture coordinate should be compared to the value in the currently bound depth texture. See the discussion of `GL_TEXTURE_COMPARE_FUNC' for details of how the comparison is evaluated. The result of the comparison is assigned to luminance, intensity, or alpha (as specified by `GL_DEPTH_TEXTURE_MODE'). `GL_NONE' Specifies that the luminance, intensity, or alpha (as specified by `GL_DEPTH_TEXTURE_MODE') should be assigned the appropriate value from the currently bound depth texture. *Texture Comparison Function* *Computed result* `GL_LEQUAL' RESULT={(1.0), (0.0)\u2062\xa0(R<=D_T,), (R>D_T,), `GL_GEQUAL' RESULT={(1.0), (0.0)\u2062\xa0(R>=D_T,), (R=D_T,), `GL_GREATER' RESULT={(1.0), (0.0)\u2062\xa0(R>D_T,), (R<=D_T,), `GL_EQUAL' RESULT={(1.0), (0.0)\u2062\xa0(R=D_T,), (R≠D_T,), `GL_NOTEQUAL' RESULT={(1.0), (0.0)\u2062\xa0(R≠D_T,), (R=D_T,), `GL_ALWAYS' RESULT=`1.0' `GL_NEVER' RESULT=`0.0' `GL_INVALID_ENUM' is generated if TARGET or PNAME is not one of the accepted defined values. `GL_INVALID_ENUM' is generated if PARAMS should have a defined constant value (based on the value of PNAME) and does not. `GL_INVALID_OPERATION' is generated if `glTexParameter' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexSubImage1D (target GLenum) (level GLint) (xoffset GLint) (width GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a one-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_1D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. WIDTH Specifies the width of the texture subimage. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable or disable one-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_1D'. `glTexSubImage1D' redefines a contiguous subregion of an existing one-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with width of 0, but such a specification has no effect. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if TARGET is not one of the allowable values. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted format constant. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2 MAX, where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , or if (XOFFSET+WIDTH,)>(W-B,) , where W is the `GL_TEXTURE_WIDTH', and B is the width of the `GL_TEXTURE_BORDER' of the texture image being modified. Note that W includes twice the border width. `GL_INVALID_VALUE' is generated if WIDTH is less than 0. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage1D' operation. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexSubImage1D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexSubImage2D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (width GLsizei) (height GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a two-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable two-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_2D'. `glTexSubImage2D' redefines a contiguous subregion of an existing two-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , inclusive, and y indices YOFFSET and YOFFSET+HEIGHT-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with zero width or height, but such a specification has no effect. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if TARGET is not `GL_TEXTURE_2D', `GL_TEXTURE_CUBE_MAP_POSITIVE_X', `GL_TEXTURE_CUBE_MAP_NEGATIVE_X', `GL_TEXTURE_CUBE_MAP_POSITIVE_Y', `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y', `GL_TEXTURE_CUBE_MAP_POSITIVE_Z', or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z'. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted format constant. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2 MAX, where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , (XOFFSET+WIDTH,)>(W-B,) , YOFFSET<-B , or (YOFFSET+HEIGHT,)>(H-B,) , where W is the `GL_TEXTURE_WIDTH', H is the `GL_TEXTURE_HEIGHT', and B is the border width of the texture image being modified. Note that W and H include twice the border width. `GL_INVALID_VALUE' is generated if WIDTH or HEIGHT is less than 0. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage2D' operation. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexSubImage2D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTexSubImage3D (target GLenum) (level GLint) (xoffset GLint) (yoffset GLint) (zoffset GLint) (width GLsizei) (height GLsizei) (depth GLsizei) (format GLenum) (type GLenum) (data const-GLvoid-*) -> void)) "Specify a three-dimensional texture subimage. TARGET Specifies the target texture. Must be `GL_TEXTURE_3D'. LEVEL Specifies the level-of-detail number. Level 0 is the base image level. Level N is the Nth mipmap reduction image. XOFFSET Specifies a texel offset in the x direction within the texture array. YOFFSET Specifies a texel offset in the y direction within the texture array. ZOFFSET Specifies a texel offset in the z direction within the texture array. WIDTH Specifies the width of the texture subimage. HEIGHT Specifies the height of the texture subimage. DEPTH Specifies the depth of the texture subimage. FORMAT Specifies the format of the pixel data. The following symbolic values are accepted: `GL_COLOR_INDEX', `GL_RED', `GL_GREEN', `GL_BLUE', `GL_ALPHA', `GL_RGB', `GL_BGR', `GL_RGBA', `GL_BGRA', `GL_LUMINANCE', and `GL_LUMINANCE_ALPHA'. TYPE Specifies the data type of the pixel data. The following symbolic values are accepted: `GL_UNSIGNED_BYTE', `GL_BYTE', `GL_BITMAP', `GL_UNSIGNED_SHORT', `GL_SHORT', `GL_UNSIGNED_INT', `GL_INT', `GL_FLOAT', `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', `GL_UNSIGNED_SHORT_5_6_5_REV', `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', and `GL_UNSIGNED_INT_2_10_10_10_REV'. DATA Specifies a pointer to the image data in memory. Texturing maps a portion of a specified texture image onto each graphical primitive for which texturing is enabled. To enable and disable three-dimensional texturing, call `glEnable' and `glDisable' with argument `GL_TEXTURE_3D'. `glTexSubImage3D' redefines a contiguous subregion of an existing three-dimensional texture image. The texels referenced by DATA replace the portion of the existing texture array with x indices XOFFSET and XOFFSET+WIDTH-1 , inclusive, y indices YOFFSET and YOFFSET+HEIGHT-1 , inclusive, and z indices ZOFFSET and ZOFFSET+DEPTH-1 , inclusive. This region may not include any texels outside the range of the texture array as it was originally specified. It is not an error to specify a subtexture with zero width, height, or depth but such a specification has no effect. If a non-zero named buffer object is bound to the `GL_PIXEL_UNPACK_BUFFER' target (see `glBindBuffer') while a texture image is specified, DATA is treated as a byte offset into the buffer object's data store. `GL_INVALID_ENUM' is generated if /TARGET is not `GL_TEXTURE_3D'. `GL_INVALID_ENUM' is generated if FORMAT is not an accepted format constant. `GL_INVALID_ENUM' is generated if TYPE is not a type constant. `GL_INVALID_ENUM' is generated if TYPE is `GL_BITMAP' and FORMAT is not `GL_COLOR_INDEX'. `GL_INVALID_VALUE' is generated if LEVEL is less than 0. `GL_INVALID_VALUE' may be generated if LEVEL is greater than LOG_2 MAX, where MAX is the returned value of `GL_MAX_TEXTURE_SIZE'. `GL_INVALID_VALUE' is generated if XOFFSET<-B , (XOFFSET+WIDTH,)>(W-B,) , YOFFSET<-B , or (YOFFSET+HEIGHT,)>(H-B,) , or ZOFFSET<-B , or (ZOFFSET+DEPTH,)>(D-B,) , where W is the `GL_TEXTURE_WIDTH', H is the `GL_TEXTURE_HEIGHT', D is the `GL_TEXTURE_DEPTH' and B is the border width of the texture image being modified. Note that W , H , and D include twice the border width. `GL_INVALID_VALUE' is generated if WIDTH, HEIGHT, or DEPTH is less than 0. `GL_INVALID_OPERATION' is generated if the texture array has not been defined by a previous `glTexImage3D' operation. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_BYTE_3_3_2', `GL_UNSIGNED_BYTE_2_3_3_REV', `GL_UNSIGNED_SHORT_5_6_5', or `GL_UNSIGNED_SHORT_5_6_5_REV' and FORMAT is not `GL_RGB'. `GL_INVALID_OPERATION' is generated if TYPE is one of `GL_UNSIGNED_SHORT_4_4_4_4', `GL_UNSIGNED_SHORT_4_4_4_4_REV', `GL_UNSIGNED_SHORT_5_5_5_1', `GL_UNSIGNED_SHORT_1_5_5_5_REV', `GL_UNSIGNED_INT_8_8_8_8', `GL_UNSIGNED_INT_8_8_8_8_REV', `GL_UNSIGNED_INT_10_10_10_2', or `GL_UNSIGNED_INT_2_10_10_10_REV' and FORMAT is neither `GL_RGBA' nor `GL_BGRA'. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the buffer object's data store is currently mapped. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and the data would be unpacked from the buffer object such that the memory reads required would exceed the data store size. `GL_INVALID_OPERATION' is generated if a non-zero buffer object name is bound to the `GL_PIXEL_UNPACK_BUFFER' target and DATA is not evenly divisible into the number of bytes needed to store in memory a datum indicated by TYPE. `GL_INVALID_OPERATION' is generated if `glTexSubImage3D' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glTranslatef (x GLfloat) (y GLfloat) (z GLfloat) -> void)) "Multiply the current matrix by a translation matrix. X Y Z Specify the X, Y, and Z coordinates of a translation vector. `glTranslate' produces a translation by (X,YZ) . The current matrix (see `glMatrixMode') is multiplied by this translation matrix, with the product replacing the current matrix, as if `glMultMatrix' were called with the following matrix for its argument: ((1 0 0 X), (0 1 0 Y), (0 0 1 Z), (0 0 0 1),) If the matrix mode is either `GL_MODELVIEW' or `GL_PROJECTION', all objects drawn after a call to `glTranslate' are translated. Use `glPushMatrix' and `glPopMatrix' to save and restore the untranslated coordinate system. `GL_INVALID_OPERATION' is generated if `glTranslate' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glUniform1f (location GLint) (v0 GLfloat) -> void) (glUniform2f (location GLint) (v0 GLfloat) (v1 GLfloat) -> void) (glUniform3f (location GLint) (v0 GLfloat) (v1 GLfloat) (v2 GLfloat) -> void) (glUniform4f (location GLint) (v0 GLfloat) (v1 GLfloat) (v2 GLfloat) (v3 GLfloat) -> void) (glUniform1i (location GLint) (v0 GLint) -> void) (glUniform2i (location GLint) (v0 GLint) (v1 GLint) -> void) (glUniform3i (location GLint) (v0 GLint) (v1 GLint) (v2 GLint) -> void) (glUniform4i (location GLint) (v0 GLint) (v1 GLint) (v2 GLint) (v3 GLint) -> void) (glUniformMatrix2fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix3fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix4fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix2x3fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix3x2fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix2x4fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix4x2fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix3x4fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void) (glUniformMatrix4x3fv (location GLint) (count GLsizei) (transpose GLboolean) (value const-GLfloat-*) -> void)) "Specify the value of a uniform variable for the current program object. LOCATION Specifies the location of the uniform variable to be modified. V0, V1, V2, V3 Specifies the new values to be used for the specified uniform variable. `glUniform' modifies the value of a uniform variable or a uniform variable array. The location of the uniform variable to be modified is specified by LOCATION, which should be a value returned by `glGetUniformLocation'. `glUniform' operates on the program object that was made part of current state by calling `glUseProgram'. The commands `glUniform{1|2|3|4}{f|i}' are used to change the value of the uniform variable specified by LOCATION using the values passed as arguments. The number specified in the command should match the number of components in the data type of the specified uniform variable (e.g., `1' for float, int, bool; `2' for vec2, ivec2, bvec2, etc.). The suffix `f' indicates that floating-point values are being passed; the suffix `i' indicates that integer values are being passed, and this type should also match the data type of the specified uniform variable. The `i' variants of this function should be used to provide values for uniform variables defined as int, ivec2, ivec3, ivec4, or arrays of these. The `f' variants should be used to provide values for uniform variables of type float, vec2, vec3, vec4, or arrays of these. Either the `i' or the `f' variants may be used to provide values for uniform variables of type bool, bvec2, bvec3, bvec4, or arrays of these. The uniform variable will be set to false if the input value is 0 or 0.0f, and it will be set to true otherwise. All active uniform variables defined in a program object are initialized to 0 when the program object is linked successfully. They retain the values assigned to them by a call to `glUniform ' until the next successful link operation occurs on the program object, when they are once again initialized to 0. The commands `glUniform{1|2|3|4}{f|i}v' can be used to modify a single uniform variable or a uniform variable array. These commands pass a count and a pointer to the values to be loaded into a uniform variable or a uniform variable array. A count of 1 should be used if modifying the value of a single uniform variable, and a count of 1 or greater can be used to modify an entire array or part of an array. When loading N elements starting at an arbitrary position M in a uniform variable array, elements M + N - 1 in the array will be replaced with the new values. If M + N - 1 is larger than the size of the uniform variable array, values for all array elements beyond the end of the array will be ignored. The number specified in the name of the command indicates the number of components for each element in VALUE, and it should match the number of components in the data type of the specified uniform variable (e.g., `1' for float, int, bool; `2' for vec2, ivec2, bvec2, etc.). The data type specified in the name of the command must match the data type for the specified uniform variable as described previously for `glUniform{1|2|3|4}{f|i}'. For uniform variable arrays, each element of the array is considered to be of the type indicated in the name of the command (e.g., `glUniform3f' or `glUniform3fv' can be used to load a uniform variable array of type vec3). The number of elements of the uniform variable array to be modified is specified by COUNT The commands `glUniformMatrix{2|3|4|2x3|3x2|2x4|4x2|3x4|4x3}fv' are used to modify a matrix or an array of matrices. The numbers in the command name are interpreted as the dimensionality of the matrix. The number `2' indicates a 2 × 2 matrix (i.e., 4 values), the number `3' indicates a 3 × 3 matrix (i.e., 9 values), and the number `4' indicates a 4 × 4 matrix (i.e., 16 values). Non-square matrix dimensionality is explicit, with the first number representing the number of columns and the second number representing the number of rows. For example, `2x4' indicates a 2 × 4 matrix with 2 columns and 4 rows (i.e., 8 values). If TRANSPOSE is `GL_FALSE', each matrix is assumed to be supplied in column major order. If TRANSPOSE is `GL_TRUE', each matrix is assumed to be supplied in row major order. The COUNT argument indicates the number of matrices to be passed. A count of 1 should be used if modifying the value of a single matrix, and a count greater than 1 can be used to modify an array of matrices. `GL_INVALID_OPERATION' is generated if there is no current program object. `GL_INVALID_OPERATION' is generated if the size of the uniform variable declared in the shader does not match the size indicated by the `glUniform' command. `GL_INVALID_OPERATION' is generated if one of the integer variants of this function is used to load a uniform variable of type float, vec2, vec3, vec4, or an array of these, or if one of the floating-point variants of this function is used to load a uniform variable of type int, ivec2, ivec3, or ivec4, or an array of these. `GL_INVALID_OPERATION' is generated if LOCATION is an invalid uniform location for the current program object and LOCATION is not equal to -1. `GL_INVALID_VALUE' is generated if COUNT is less than 0. `GL_INVALID_OPERATION' is generated if COUNT is greater than 1 and the indicated uniform variable is not an array variable. `GL_INVALID_OPERATION' is generated if a sampler is loaded using a command other than `glUniform1i' and `glUniform1iv'. `GL_INVALID_OPERATION' is generated if `glUniform' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glUseProgram (program GLuint) -> void)) "Installs a program object as part of current rendering state. PROGRAM Specifies the handle of the program object whose executables are to be used as part of current rendering state. `glUseProgram' installs the program object specified by PROGRAM as part of current rendering state. One or more executables are created in a program object by successfully attaching shader objects to it with `glAttachShader', successfully compiling the shader objects with `glCompileShader', and successfully linking the program object with `glLinkProgram'. A program object will contain an executable that will run on the vertex processor if it contains one or more shader objects of type `GL_VERTEX_SHADER' that have been successfully compiled and linked. Similarly, a program object will contain an executable that will run on the fragment processor if it contains one or more shader objects of type `GL_FRAGMENT_SHADER' that have been successfully compiled and linked. Successfully installing an executable on a programmable processor will cause the corresponding fixed functionality of OpenGL to be disabled. Specifically, if an executable is installed on the vertex processor, the OpenGL fixed functionality will be disabled as follows. * The projection matrix is not applied to vertex coordinates. * The texture matrices are not applied to texture coordinates. * Normals are not transformed to eye coordinates. * Normals are not rescaled or normalized. * Normalization of `GL_AUTO_NORMAL' evaluated normals is not performed. * Texture coordinates are not generated automatically. * Per-vertex lighting is not performed. * Color material computations are not performed. * Color index lighting is not performed. * This list also applies when setting the current raster position. The executable that is installed on the vertex processor is expected to implement any or all of the desired functionality from the preceding list. Similarly, if an executable is installed on the fragment processor, the OpenGL fixed functionality will be disabled as follows. * Texture application is not applied. * Color sum is not applied. * Fog is not applied. Again, the fragment shader that is installed is expected to implement any or all of the desired functionality from the preceding list. While a program object is in use, applications are free to modify attached shader objects, compile attached shader objects, attach additional shader objects, and detach or delete shader objects. None of these operations will affect the executables that are part of the current state. However, relinking the program object that is currently in use will install the program object as part of the current rendering state if the link operation was successful (see `glLinkProgram' ). If the program object currently in use is relinked unsuccessfully, its link status will be set to `GL_FALSE', but the executables and associated state will remain part of the current state until a subsequent call to `glUseProgram' removes it from use. After it is removed from use, it cannot be made part of current state until it has been successfully relinked. If PROGRAM contains shader objects of type `GL_VERTEX_SHADER' but it does not contain shader objects of type `GL_FRAGMENT_SHADER', an executable will be installed on the vertex processor, but fixed functionality will be used for fragment processing. Similarly, if PROGRAM contains shader objects of type `GL_FRAGMENT_SHADER' but it does not contain shader objects of type `GL_VERTEX_SHADER', an executable will be installed on the fragment processor, but fixed functionality will be used for vertex processing. If PROGRAM is 0, the programmable processors will be disabled, and fixed functionality will be used for both vertex and fragment processing. `GL_INVALID_VALUE' is generated if PROGRAM is neither 0 nor a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if PROGRAM could not be made part of current state. `GL_INVALID_OPERATION' is generated if `glUseProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glValidateProgram (program GLuint) -> void)) "Validates a program object. PROGRAM Specifies the handle of the program object to be validated. `glValidateProgram' checks to see whether the executables contained in PROGRAM can execute given the current OpenGL state. The information generated by the validation process will be stored in PROGRAM's information log. The validation information may consist of an empty string, or it may be a string containing information about how the current program object interacts with the rest of current OpenGL state. This provides a way for OpenGL implementers to convey more information about why the current program is inefficient, suboptimal, failing to execute, and so on. The status of the validation operation will be stored as part of the program object's state. This value will be set to `GL_TRUE' if the validation succeeded, and `GL_FALSE' otherwise. It can be queried by calling `glGetProgram' with arguments PROGRAM and `GL_VALIDATE_STATUS'. If validation is successful, PROGRAM is guaranteed to execute given the current state. Otherwise, PROGRAM is guaranteed to not execute. This function is typically useful only during application development. The informational string stored in the information log is completely implementation dependent; therefore, an application should not expect different OpenGL implementations to produce identical information strings. `GL_INVALID_VALUE' is generated if PROGRAM is not a value generated by OpenGL. `GL_INVALID_OPERATION' is generated if PROGRAM is not a program object. `GL_INVALID_OPERATION' is generated if `glValidateProgram' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glVertexAttribPointer (index GLuint) (size GLint) (type GLenum) (normalized GLboolean) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of generic vertex attribute data. INDEX Specifies the index of the generic vertex attribute to be modified. SIZE Specifies the number of components per generic vertex attribute. Must be 1, 2, 3, or 4. The initial value is 4. TYPE Specifies the data type of each component in the array. Symbolic constants `GL_BYTE', `GL_UNSIGNED_BYTE', `GL_SHORT', `GL_UNSIGNED_SHORT', `GL_INT', `GL_UNSIGNED_INT', `GL_FLOAT', or `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. NORMALIZED Specifies whether fixed-point data values should be normalized (`GL_TRUE') or converted directly as fixed-point values (`GL_FALSE') when they are accessed. STRIDE Specifies the byte offset between consecutive generic vertex attributes. If STRIDE is 0, the generic vertex attributes are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first component of the first generic vertex attribute in the array. The initial value is 0. `glVertexAttribPointer' specifies the location and data format of the array of generic vertex attributes at index INDEX to use when rendering. SIZE specifies the number of components per attribute and must be 1, 2, 3, or 4. TYPE specifies the data type of each component, and STRIDE specifies the byte stride from one attribute to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. If set to `GL_TRUE', NORMALIZED indicates that values stored in an integer format are to be mapped to the range [-1,1] (for signed values) or [0,1] (for unsigned values) when they are accessed and converted to floating point. Otherwise, values will be converted to floats directly without normalization. If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a generic vertex attribute array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as generic vertex attribute array client-side state (`GL_VERTEX_ATTRIB_ARRAY_BUFFER_BINDING') for index INDEX. When a generic vertex attribute array is specified, SIZE, TYPE, NORMALIZED, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable a generic vertex attribute array, call `glEnableVertexAttribArray' and `glDisableVertexAttribArray' with INDEX. If enabled, the generic vertex attribute array is used when `glArrayElement', `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', or `glDrawRangeElements' is called. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'. `GL_INVALID_VALUE' is generated if SIZE is not 1, 2, 3, or 4. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glVertexAttrib1f (index GLuint) (v0 GLfloat) -> void) (glVertexAttrib1s (index GLuint) (v0 GLshort) -> void) (glVertexAttrib2f (index GLuint) (v0 GLfloat) (v1 GLfloat) -> void) (glVertexAttrib2s (index GLuint) (v0 GLshort) (v1 GLshort) -> void) (glVertexAttrib3f (index GLuint) (v0 GLfloat) (v1 GLfloat) (v2 GLfloat) -> void) (glVertexAttrib3s (index GLuint) (v0 GLshort) (v1 GLshort) (v2 GLshort) -> void) (glVertexAttrib4f (index GLuint) (v0 GLfloat) (v1 GLfloat) (v2 GLfloat) (v3 GLfloat) -> void) (glVertexAttrib4s (index GLuint) (v0 GLshort) (v1 GLshort) (v2 GLshort) (v3 GLshort) -> void) (glVertexAttrib4Nub (index GLuint) (v0 GLubyte) (v1 GLubyte) (v2 GLubyte) (v3 GLubyte) -> void) (glVertexAttrib4iv (index GLuint) (v const-GLint-*) -> void) (glVertexAttrib4uiv (index GLuint) (v const-GLuint-*) -> void) (glVertexAttrib4Niv (index GLuint) (v const-GLint-*) -> void) (glVertexAttrib4Nuiv (index GLuint) (v const-GLuint-*) -> void)) "Specifies the value of a generic vertex attribute. INDEX Specifies the index of the generic vertex attribute to be modified. V0, V1, V2, V3 Specifies the new values to be used for the specified vertex attribute. OpenGL defines a number of standard vertex attributes that applications can modify with standard API entry points (color, normal, texture coordinates, etc.). The `glVertexAttrib' family of entry points allows an application to pass generic vertex attributes in numbered locations. Generic attributes are defined as four-component values that are organized into an array. The first entry of this array is numbered 0, and the size of the array is specified by the implementation-dependent constant `GL_MAX_VERTEX_ATTRIBS'. Individual elements of this array can be modified with a `glVertexAttrib' call that specifies the index of the element to be modified and a value for that element. These commands can be used to specify one, two, three, or all four components of the generic vertex attribute specified by INDEX. A `1' in the name of the command indicates that only one value is passed, and it will be used to modify the first component of the generic vertex attribute. The second and third components will be set to 0, and the fourth component will be set to 1. Similarly, a `2' in the name of the command indicates that values are provided for the first two components, the third component will be set to 0, and the fourth component will be set to 1. A `3' in the name of the command indicates that values are provided for the first three components and the fourth component will be set to 1, whereas a `4' in the name indicates that values are provided for all four components. The letters `s', `f', `i', `d', `ub', `us', and `ui' indicate whether the arguments are of type short, float, int, double, unsigned byte, unsigned short, or unsigned int. When `v' is appended to the name, the commands can take a pointer to an array of such values. The commands containing `N' indicate that the arguments will be passed as fixed-point values that are scaled to a normalized range according to the component conversion rules defined by the OpenGL specification. Signed values are understood to represent fixed-point values in the range [-1,1], and unsigned values are understood to represent fixed-point values in the range [0,1]. OpenGL Shading Language attribute variables are allowed to be of type mat2, mat3, or mat4. Attributes of these types may be loaded using the `glVertexAttrib' entry points. Matrices must be loaded into successive generic attribute slots in column major order, with one column of the matrix in each generic attribute slot. A user-defined attribute variable declared in a vertex shader can be bound to a generic attribute index by calling `glBindAttribLocation'. This allows an application to use more descriptive variable names in a vertex shader. A subsequent change to the specified generic vertex attribute will be immediately reflected as a change to the corresponding attribute variable in the vertex shader. The binding between a generic vertex attribute index and a user-defined attribute variable in a vertex shader is part of the state of a program object, but the current value of the generic vertex attribute is not. The value of each generic vertex attribute is part of current state, just like standard vertex attributes, and it is maintained even if a different program object is used. An application may freely modify generic vertex attributes that are not bound to a named vertex shader attribute variable. These values are simply maintained as part of current state and will not be accessed by the vertex shader. If a generic vertex attribute bound to an attribute variable in a vertex shader is not updated while the vertex shader is executing, the vertex shader will repeatedly use the current value for the generic vertex attribute. The generic vertex attribute with index 0 is the same as the vertex position attribute previously defined by OpenGL. A `glVertex2', `glVertex3', or `glVertex4' command is completely equivalent to the corresponding `glVertexAttrib' command with an index argument of 0. A vertex shader can access generic vertex attribute 0 by using the built-in attribute variable GL_VERTEX. There are no current values for generic vertex attribute 0. This is the only generic vertex attribute with this property; calls to set other standard vertex attributes can be freely mixed with calls to set any of the other generic vertex attributes. `GL_INVALID_VALUE' is generated if INDEX is greater than or equal to `GL_MAX_VERTEX_ATTRIBS'.") (define-gl-procedures ((glVertexPointer (size GLint) (type GLenum) (stride GLsizei) (pointer const-GLvoid-*) -> void)) "Define an array of vertex data. SIZE Specifies the number of coordinates per vertex. Must be 2, 3, or 4. The initial value is 4. TYPE Specifies the data type of each coordinate in the array. Symbolic constants `GL_SHORT', `GL_INT', `GL_FLOAT', or `GL_DOUBLE' are accepted. The initial value is `GL_FLOAT'. STRIDE Specifies the byte offset between consecutive vertices. If STRIDE is 0, the vertices are understood to be tightly packed in the array. The initial value is 0. POINTER Specifies a pointer to the first coordinate of the first vertex in the array. The initial value is 0. `glVertexPointer' specifies the location and data format of an array of vertex coordinates to use when rendering. SIZE specifies the number of coordinates per vertex, and must be 2, 3, or 4. TYPE specifies the data type of each coordinate, and STRIDE specifies the byte stride from one vertex to the next, allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see `glInterleavedArrays'.) If a non-zero named buffer object is bound to the `GL_ARRAY_BUFFER' target (see `glBindBuffer') while a vertex array is specified, POINTER is treated as a byte offset into the buffer object's data store. Also, the buffer object binding (`GL_ARRAY_BUFFER_BINDING') is saved as vertex array client-side state (`GL_VERTEX_ARRAY_BUFFER_BINDING'). When a vertex array is specified, SIZE, TYPE, STRIDE, and POINTER are saved as client-side state, in addition to the current vertex array buffer object binding. To enable and disable the vertex array, call `glEnableClientState' and `glDisableClientState' with the argument `GL_VERTEX_ARRAY'. If enabled, the vertex array is used when `glArrayElement', `glDrawArrays', `glMultiDrawArrays', `glDrawElements', `glMultiDrawElements', or `glDrawRangeElements' is called. `GL_INVALID_VALUE' is generated if SIZE is not 2, 3, or 4. `GL_INVALID_ENUM' is generated if TYPE is not an accepted value. `GL_INVALID_VALUE' is generated if STRIDE is negative.") (define-gl-procedures ((glVertex2i (x GLint) (y GLint) -> void) (glVertex2f (x GLfloat) (y GLfloat) -> void) (glVertex3i (x GLint) (y GLint) (z GLint) -> void) (glVertex3f (x GLfloat) (y GLfloat) (z GLfloat) -> void) (glVertex4i (x GLint) (y GLint) (z GLint) (w GLint) -> void) (glVertex4f (x GLfloat) (y GLfloat) (z GLfloat) (w GLfloat) -> void)) "Specify a vertex. X Y Z W Specify X, Y, Z, and W coordinates of a vertex. Not all parameters are present in all forms of the command. `glVertex' commands are used within `glBegin'/`glEnd' pairs to specify point, line, and polygon vertices. The current color, normal, texture coordinates, and fog coordinate are associated with the vertex when `glVertex' is called. When only X and Y are specified, Z defaults to 0 and W defaults to 1. When X , Y , and Z are specified, W defaults to 1.") (define-gl-procedures ((glViewport (x GLint) (y GLint) (width GLsizei) (height GLsizei) -> void)) "Set the viewport. X Y Specify the lower left corner of the viewport rectangle, in pixels. The initial value is (0,0). WIDTH HEIGHT Specify the width and height of the viewport. When a GL context is first attached to a window, WIDTH and HEIGHT are set to the dimensions of that window. `glViewport' specifies the affine transformation of X and Y from normalized device coordinates to window coordinates. Let (X_ND,Y_ND) be normalized device coordinates. Then the window coordinates (X_W,Y_W) are computed as follows: X_W=(X_ND+1,)\u2062(WIDTH/2,)+X Y_W=(Y_ND+1,)\u2062(HEIGHT/2,)+Y Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call `glGet' with argument `GL_MAX_VIEWPORT_DIMS'. `GL_INVALID_VALUE' is generated if either WIDTH or HEIGHT is negative. `GL_INVALID_OPERATION' is generated if `glViewport' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.") (define-gl-procedures ((glWindowPos2i (x GLint) (y GLint) -> void) (glWindowPos2f (x GLfloat) (y GLfloat) -> void) (glWindowPos3i (x GLint) (y GLint) (z GLint) -> void) (glWindowPos3f (x GLfloat) (y GLfloat) (z GLfloat) -> void)) "Specify the raster position in window coordinates for pixel operations. X Y Z Specify the X , Y , Z coordinates for the raster position. The GL maintains a 3D position in window coordinates. This position, called the raster position, is used to position pixel and bitmap write operations. It is maintained with subpixel accuracy. See `glBitmap', `glDrawPixels', and `glCopyPixels'. `glWindowPos2' specifies the X and Y coordinates, while Z is implicitly set to 0. `glWindowPos3' specifies all three coordinates. The W coordinate of the current raster position is always set to 1.0. `glWindowPos' directly updates the X and Y coordinates of the current raster position with the values specified. That is, the values are neither transformed by the current modelview and projection matrices, nor by the viewport-to-window transform. The Z coordinate of the current raster position is updated in the following manner: Z={(N), (F), (N+Z×(F-N,),)\u2062(IF\u2062Z<=0), (IF\u2062Z>=1), (`otherwise',), where N is `GL_DEPTH_RANGE''s near value, and F is `GL_DEPTH_RANGE''s far value. See `glDepthRange'. The specified coordinates are not clip-tested, causing the raster position to always be valid. The current raster position also includes some associated color data and texture coordinates. If lighting is enabled, then `GL_CURRENT_RASTER_COLOR' (in RGBA mode) or `GL_CURRENT_RASTER_INDEX' (in color index mode) is set to the color produced by the lighting calculation (see `glLight', `glLightModel', and `glShadeModel'). If lighting is disabled, current color (in RGBA mode, state variable `GL_CURRENT_COLOR') or color index (in color index mode, state variable `GL_CURRENT_INDEX') is used to update the current raster color. `GL_CURRENT_RASTER_SECONDARY_COLOR' (in RGBA mode) is likewise updated. Likewise, `GL_CURRENT_RASTER_TEXTURE_COORDS' is updated as a function of `GL_CURRENT_TEXTURE_COORDS', based on the texture matrix and the texture generation functions (see `glTexGen'). The `GL_CURRENT_RASTER_DISTANCE' is set to the `GL_CURRENT_FOG_COORD'. `GL_INVALID_OPERATION' is generated if `glWindowPos' is executed between the execution of `glBegin' and the corresponding execution of `glEnd'.")