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+<?xml version="1.0" encoding="UTF-8"?>
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+<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><link rel="stylesheet" type="text/css" href="opengl-man.css" /><title>glEnable - OpenGL 4 Reference Pages</title><meta name="generator" content="DocBook XSL Stylesheets V1.69.1" /></head><body><div class="refentry" lang="en" xml:lang="en"><a id="glEnable"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glEnable — enable or disable server-side GL capabilities</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glEnable</b>(</code>GLenum <var class="pdparam">cap</var><code>)</code>;</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>cap</code></em></span></dt><dd><p>
+ Specifies a symbolic constant indicating a GL capability.
+ </p></dd></dl></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glDisable</b>(</code>GLenum <var class="pdparam">cap</var><code>)</code>;</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters2"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>cap</code></em></span></dt><dd><p>
+ Specifies a symbolic constant indicating a GL capability.
+ </p></dd></dl></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glEnablei</b>(</code>GLenum <var class="pdparam">cap</var>, GLuint <var class="pdparam">index</var><code>)</code>;</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters3"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>cap</code></em></span></dt><dd><p>
+ Specifies a symbolic constant indicating a GL capability.
+ </p></dd><dt><span class="term"><em class="parameter"><code>index</code></em></span></dt><dd><p>
+ Specifies the index of the swtich to enable.
+ </p></dd></dl></div></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><p><code class="funcdef">void <b class="fsfunc">glDisablei</b>(</code>GLenum <var class="pdparam">cap</var>, GLuint <var class="pdparam">index</var><code>)</code>;</p></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters4"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>cap</code></em></span></dt><dd><p>
+ Specifies a symbolic constant indicating a GL capability.
+ </p></dd><dt><span class="term"><em class="parameter"><code>index</code></em></span></dt><dd><p>
+ Specifies the index of the swtich to disable.
+ </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
+ <code class="function">glEnable</code> and <a href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> enable and disable various capabilities.
+ Use <a href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a> or <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> to determine the current setting
+ of any capability. The initial value for each capability with the
+ exception of <code class="constant">GL_DITHER</code> and <code class="constant">GL_MULTISAMPLE</code> is
+ <code class="constant">GL_FALSE</code>. The initial value for
+ <code class="constant">GL_DITHER</code> and <code class="constant">GL_MULTISAMPLE</code> is <code class="constant">GL_TRUE</code>.
+ </p><p>
+ Both <code class="function">glEnable</code> and <a href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a> take a single argument, <em class="parameter"><code>cap</code></em>,
+ which can assume one of the following values:
+ </p><p>
+ Some of the GL's capabilities are indexed. <code class="function">glEnablei</code> and <code class="function">glDisablei</code> enable and disable
+ indexed capabilities.
+ </p><div class="variablelist"><dl><dt><span class="term"><code class="constant">GL_BLEND</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ blend the computed fragment color values with the values in the color
+ buffers. See <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_CLIP_DISTANCE</code><span class="emphasis"><em>i</em></span></span></dt><dd><p>
+ </p><p>
+ If enabled, clip geometry against user-defined half space <span class="emphasis"><em>i</em></span>.
+ </p></dd><dt><span class="term"><code class="constant">GL_COLOR_LOGIC_OP</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ apply the currently selected logical operation to the computed fragment
+ color and color buffer values. See <a href="glLogicOp.xml"><span class="citerefentry"><span class="refentrytitle">glLogicOp</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_CULL_FACE</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ cull polygons based on their winding in window coordinates.
+ See <a href="glCullFace.xml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_DEBUG_OUTPUT</code></span></dt><dd><p>
+ </p><p>
+ If enabled, debug messages are produced by a debug context. When disabled,
+ the debug message log is silenced. Note that in a non-debug context, very
+ few, if any messages might be produced, even when <code class="constant">GL_DEBUG_OUTPUT</code>
+ is enabled.
+ </p></dd><dt><span class="term"><code class="constant">GL_DEBUG_OUTPUT_SYNCHRONOUS</code></span></dt><dd><p>
+ </p><p>
+ If enabled, debug messages are produced synchronously by a debug context. If disabled,
+ debug messages may be produced asynchronously. In particular, they may be delayed relative
+ to the execution of GL commands, and the debug callback function may be called from
+ a thread other than that in which the commands are executed.
+ See <a href="glDebugMessageCallback.xml"><span class="citerefentry"><span class="refentrytitle">glDebugMessageCallback</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_DEPTH_CLAMP</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ the
+
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">
+ <mml:mo>-</mml:mo><mml:msub><mml:mi>w</mml:mi><mml:mi>c</mml:mi></mml:msub><mml:mo>≤</mml:mo><mml:msub><mml:mi>z</mml:mi><mml:mi>c</mml:mi></mml:msub><mml:mo>≤</mml:mo><mml:msub><mml:mi>w</mml:mi><mml:mi>c</mml:mi></mml:msub>
+ </mml:math>
+ plane equation is ignored by view volume clipping (effectively, there is no near or
+ far plane clipping).
+ See <a href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_DEPTH_TEST</code></span></dt><dd><p>
+ </p><p>
+ 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
+ <a href="glDepthFunc.xml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a> and
+ <a href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_DITHER</code> </span></dt><dd><p>
+ </p><p>
+ If enabled,
+ dither color components or indices before they are written to the
+ color buffer.
+ </p></dd><dt><span class="term"><code class="constant">GL_FRAMEBUFFER_SRGB</code> </span></dt><dd><p>
+ </p><p>
+ If enabled
+ and the value of <code class="constant">GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING</code> for the
+ framebuffer attachment corresponding to the destination buffer is <code class="constant">GL_SRGB</code>,
+ the R, G, and B destination color values (after conversion from fixed-point to floating-point)
+ are considered to be encoded for the sRGB color space and hence are linearized prior to
+ their use in blending.
+ </p></dd><dt><span class="term"><code class="constant">GL_LINE_SMOOTH</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ draw lines with correct filtering.
+ Otherwise,
+ draw aliased lines.
+ See <a href="glLineWidth.xml"><span class="citerefentry"><span class="refentrytitle">glLineWidth</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_MULTISAMPLE</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ use multiple fragment samples in computing the final color of a pixel.
+ See <a href="glSampleCoverage.xml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_POLYGON_OFFSET_FILL</code></span></dt><dd><p>
+ </p><p>
+ If enabled, and if the polygon is rendered in
+ <code class="constant">GL_FILL</code> mode, an offset is added to depth values of a polygon's
+ fragments before the depth comparison is performed.
+ See <a href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_POLYGON_OFFSET_LINE</code></span></dt><dd><p>
+ </p><p>
+ If enabled, and if the polygon is rendered in
+ <code class="constant">GL_LINE</code> mode, an offset is added to depth values of a polygon's
+ fragments before the depth comparison is performed.
+ See <a href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_POLYGON_OFFSET_POINT</code></span></dt><dd><p>
+ </p><p>
+ 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
+ <code class="constant">GL_POINT</code> mode. See <a href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_POLYGON_SMOOTH</code></span></dt><dd><p>
+ </p><p>
+ 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.
+ </p></dd><dt><span class="term"><code class="constant">GL_PRIMITIVE_RESTART</code></span></dt><dd><p>
+ </p><p>
+ Enables primitive restarting. If enabled, any one of the draw commands
+ which transfers a set of generic attribute array elements to the GL will restart
+ the primitive when the index of the vertex is equal to the primitive restart index.
+ See <a href="glPrimitiveRestartIndex.xml"><span class="citerefentry"><span class="refentrytitle">glPrimitiveRestartIndex</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_PRIMITIVE_RESTART_FIXED_INDEX</code></span></dt><dd><p>
+ </p><p>
+ Enables primitive restarting with a fixed index. If enabled, any one of the
+ draw commands which transfers a set of generic attribute array elements to the GL will
+ restart the primitive when the index of the vertex is equal to the fixed primitive
+ index for the specified index type. The fixed index is equal to
+ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"><mml:msup><mml:mn>2</mml:mn><mml:mi>n</mml:mi></mml:msup><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:math>
+ where <span class="emphasis"><em>n</em></span> is equal to 8 for <code class="constant">GL_UNSIGNED_BYTE</code>,
+ 16 for <code class="constant">GL_UNSIGNED_SHORT</code> and 32 for <code class="constant">GL_UNSIGNED_INT</code>.
+ </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_ALPHA_TO_COVERAGE</code></span></dt><dd><p>
+ </p><p>
+ 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.
+ </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_ALPHA_TO_ONE</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ each sample alpha value is replaced by the maximum representable alpha value.
+ </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_COVERAGE</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ the fragment's coverage is ANDed with the temporary coverage value. If
+ <code class="constant">GL_SAMPLE_COVERAGE_INVERT</code> is set to <code class="constant">GL_TRUE</code>, invert the coverage
+ value.
+ See <a href="glSampleCoverage.xml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_SHADING</code></span></dt><dd><p>
+ </p><p>
+ If enabled, the active fragment shader is run once for each covered sample, or at
+ fraction of this rate as determined by the current value of <code class="constant">GL_MIN_SAMPLE_SHADING_VALUE</code>.
+ See <a href="glMinSampleShading.xml"><span class="citerefentry"><span class="refentrytitle">glMinSampleShading</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_SAMPLE_MASK</code></span></dt><dd><p>
+ </p><p>
+ If enabled, the sample coverage mask generated for a fragment during rasterization
+ will be ANDed with the value of <code class="constant">GL_SAMPLE_MASK_VALUE</code> before
+ shading occurs.
+ See <a href="glSampleMaski.xml"><span class="citerefentry"><span class="refentrytitle">glSampleMaski</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_SCISSOR_TEST</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ discard fragments that are outside the scissor rectangle.
+ See <a href="glScissor.xml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_STENCIL_TEST</code></span></dt><dd><p>
+ </p><p>
+ If enabled,
+ do stencil testing and update the stencil buffer.
+ See <a href="glStencilFunc.xml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a> and <a href="glStencilOp.xml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>.
+ </p></dd><dt><span class="term"><code class="constant">GL_TEXTURE_CUBE_MAP_SEAMLESS</code></span></dt><dd><p>
+ </p><p>
+ If enabled, cubemap textures are sampled such that when linearly sampling from the border
+ between two adjacent faces, texels from both faces are used to generate the final sample
+ value. When disabled, texels from only a single face are used to construct the final
+ sample value.
+ </p></dd><dt><span class="term"><code class="constant">GL_PROGRAM_POINT_SIZE</code></span></dt><dd><p>
+ </p><p>
+ If enabled
+ and a vertex or geometry shader is active, then the derived point size is taken from the (potentially clipped) shader builtin
+ <code class="constant">gl_PointSize</code> and clamped to the implementation-dependent point size range.
+ </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
+ <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>cap</code></em> is not one of the values
+ listed previously.
+ </p><p>
+ <code class="constant">GL_INVALID_VALUE</code> is generated by <code class="function">glEnablei</code> and <code class="function">glDisablei</code>
+ if <em class="parameter"><code>index</code></em> is greater than or equal to the number of indexed capabilities for <em class="parameter"><code>cap</code></em>.
+ </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
+ <code class="constant">GL_PRIMITIVE_RESTART</code> is available only if the GL version is 3.1 or greater.
+ </p><p>
+ <code class="constant">GL_TEXTURE_CUBE_MAP_SEAMLESS</code> is available only if the GL version is 3.2 or greater.
+ </p><p>
+ <code class="constant">GL_PRIMITIVE_RESTART_FIXED_INDEX</code> is available only if the GL version is 4.3 or greater.
+ </p><p>
+ <code class="constant">GL_DEBUG_OUTPUT</code> and <code class="constant">GL_DEBUG_OUTPUT_SYNCHRONOUS</code> are available only if the GL version is 4.3 or greater.
+ </p><p>
+ Any token accepted by <code class="function">glEnable</code> or <code class="function">glDisable</code> is also accepted by
+ <code class="function">glEnablei</code> and <code class="function">glDisablei</code>, but if the capability is not indexed,
+ the maximum value that <em class="parameter"><code>index</code></em> may take is zero.
+ </p><p>
+ In general, passing an indexed capability to <code class="function">glEnable</code> or <code class="function">glDisable</code>
+ will enable or disable that capability for all indices, resepectively.
+ </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
+ <a href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>
+ </p><p>
+ <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
+ </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
+ <a href="glActiveTexture.xml"><span class="citerefentry"><span class="refentrytitle">glActiveTexture</span></span></a>,
+ <a href="glBlendFunc.xml"><span class="citerefentry"><span class="refentrytitle">glBlendFunc</span></span></a>,
+ <a href="glCullFace.xml"><span class="citerefentry"><span class="refentrytitle">glCullFace</span></span></a>,
+ <a href="glDepthFunc.xml"><span class="citerefentry"><span class="refentrytitle">glDepthFunc</span></span></a>,
+ <a href="glDepthRange.xml"><span class="citerefentry"><span class="refentrytitle">glDepthRange</span></span></a>,
+ <a href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>,
+ <a href="glIsEnabled.xml"><span class="citerefentry"><span class="refentrytitle">glIsEnabled</span></span></a>,
+ <a href="glLineWidth.xml"><span class="citerefentry"><span class="refentrytitle">glLineWidth</span></span></a>,
+ <a href="glLogicOp.xml"><span class="citerefentry"><span class="refentrytitle">glLogicOp</span></span></a>,
+ <a href="glPointSize.xml"><span class="citerefentry"><span class="refentrytitle">glPointSize</span></span></a>,
+ <a href="glPolygonMode.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonMode</span></span></a>,
+ <a href="glPolygonOffset.xml"><span class="citerefentry"><span class="refentrytitle">glPolygonOffset</span></span></a>,
+ <a href="glSampleCoverage.xml"><span class="citerefentry"><span class="refentrytitle">glSampleCoverage</span></span></a>,
+ <a href="glScissor.xml"><span class="citerefentry"><span class="refentrytitle">glScissor</span></span></a>,
+ <a href="glStencilFunc.xml"><span class="citerefentry"><span class="refentrytitle">glStencilFunc</span></span></a>,
+ <a href="glStencilOp.xml"><span class="citerefentry"><span class="refentrytitle">glStencilOp</span></span></a>,
+ <a href="glTexImage1D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage1D</span></span></a>,
+ <a href="glTexImage2D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage2D</span></span></a>,
+ <a href="glTexImage3D.xml"><span class="citerefentry"><span class="refentrytitle">glTexImage3D</span></span></a>
+ </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="Copyright"></a><h2>Copyright</h2><p>
+ Copyright <span class="trademark"></span>© 1991-2006
+ Silicon Graphics, Inc. Copyright <span class="trademark"></span>© 2010-2011 Khronos Group.
+ This document is licensed under the SGI
+ Free Software B License. For details, see
+ <a href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
+ </p></div></div></body></html>
HCoop / clinton / guile-figl.git / blobdiff