1GLDEPTHFUNC(3G)                  OpenGL Manual                 GLDEPTHFUNC(3G)
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NAME

6       glDepthFunc - specify the value used for depth buffer comparisons
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C SPECIFICATION

9       void glDepthFunc(GLenum func);
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PARAMETERS

12       func
13           Specifies the depth comparison function. Symbolic constants
14           GL_NEVER, GL_LESS, GL_EQUAL, GL_LEQUAL, GL_GREATER, GL_NOTEQUAL,
15           GL_GEQUAL, and GL_ALWAYS are accepted. The initial value is
16           GL_LESS.
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DESCRIPTION

19       glDepthFunc specifies the function used to compare each incoming pixel
20       depth value with the depth value present in the depth buffer. The
21       comparison is performed only if depth testing is enabled. (See
22       glEnable() and glDisable() of GL_DEPTH_TEST.)
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24       func specifies the conditions under which the pixel will be drawn. The
25       comparison functions are as follows:
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27       GL_NEVER
28           Never passes.
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30       GL_LESS
31           Passes if the incoming depth value is less than the stored depth
32           value.
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34       GL_EQUAL
35           Passes if the incoming depth value is equal to the stored depth
36           value.
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38       GL_LEQUAL
39           Passes if the incoming depth value is less than or equal to the
40           stored depth value.
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42       GL_GREATER
43           Passes if the incoming depth value is greater than the stored depth
44           value.
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46       GL_NOTEQUAL
47           Passes if the incoming depth value is not equal to the stored depth
48           value.
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50       GL_GEQUAL
51           Passes if the incoming depth value is greater than or equal to the
52           stored depth value.
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54       GL_ALWAYS
55           Always passes.
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57       The initial value of func is GL_LESS. Initially, depth testing is
58       disabled. If depth testing is disabled or if no depth buffer exists, it
59       is as if the depth test always passes.
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NOTES

62       Even if the depth buffer exists and the depth mask is non-zero, the
63       depth buffer is not updated if the depth test is disabled. In order to
64       unconditionally write to the depth buffer, the depth test should be
65       enabled and set to GL_ALWAYS.
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ERRORS

68       GL_INVALID_ENUM is generated if func is not an accepted value.
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ASSOCIATED GETS

71       glGet() with argument GL_DEPTH_FUNC
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73       glIsEnabled() with argument GL_DEPTH_TEST
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SEE ALSO

76       glDepthRange(), glEnable(), glPolygonOffset()
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79       Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed
80       under the SGI Free Software B License. For details, see
81       http://oss.sgi.com/projects/FreeB/.
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AUTHORS

84       opengl.org
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88opengl.org                        06/10/2014                   GLDEPTHFUNC(3G)
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