X-Git-Url: http://git.hcoop.net/clinton/guile-figl.git/blobdiff_plain/b002944dd992dc5a273e0067504beb48e1ae3d1c..a6a00658f26c164551287799b194cc2f07eb78be:/upstream-doc/man4/glDepthFunc.xml diff --git a/upstream-doc/man4/glDepthFunc.xml b/upstream-doc/man4/glDepthFunc.xml new file mode 100644 index 0000000..51900ad --- /dev/null +++ b/upstream-doc/man4/glDepthFunc.xml @@ -0,0 +1,170 @@ + + + + + + + 1991-2006 + Silicon Graphics, Inc. + + + glDepthFunc + 3G + + + glDepthFunc + specify the value used for depth buffer comparisons + + C Specification + + + void glDepthFunc + GLenum func + + + + Parameters + + + 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. + + + + + + Description + + 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. + + + Notes + + 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. In order to + unconditionally write to the depth buffer, the depth test should be enabled + and set to GL_ALWAYS. + + + Errors + + GL_INVALID_ENUM is generated if func is not an accepted value. + + + Associated Gets + + glGet with argument GL_DEPTH_FUNC + + + glIsEnabled with argument GL_DEPTH_TEST + + + See Also + + glDepthRange, + glEnable, + glPolygonOffset + + + Copyright + + Copyright 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/. + + +