- specify the value used for depth buffer comparisons
C SPECIFICATION
PARAMETERS
_param1 Specifies the depth comparison function. Sym-
bolic 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.)
_param1 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 _param1 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.
ERRORS
GL_INVALID_ENUM is generated if _param1 is not an accepted
value.
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