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glDepthFunc - specify the value used for depth buffer comparisons
void glDepthFunc( GLenum func )
- 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. 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.
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.
glGet with argument GL_DEPTH_FUNC
glIsEnabled with argument GL_DEPTH_TEST
glDepthRange(3G)
, glEnable(3G)
,
glPolygonOffset(3G)
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