glDepthFunc
NAME
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 default value is GL_LESS.
DESCRIPTION
glDepthFunc specifies the function used to compare each incoming pixel
z value with the z 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 z value is less than the
stored z value.
- GL_EQUAL
- Passes if the incoming z value is equal to the
stored z value.
- GL_LEQUAL
- Passes if the incoming z value is less than or
equal to the stored z value.
- GL_GREATER
- Passes if the incoming z value is greater than
the stored z value.
- GL_NOTEQUAL
- Passes if the incoming z value is not equal to
the stored z value.
- GL_GEQUAL
- Passes if the incoming z value is greater than
or equal to the stored z value.
- GL_ALWAYS
- Always passes.
The default value of func is GL_LESS. Initially, depth testing is disabled.
ERRORS
GL_INVALID_ENUM is generated if func is not an accepted value.
GL_INVALID_OPERATION is generated if glDepthFunc is called
between a call to glBegin and the
corresponding call to glEnd.
ASSOCIATED GETS
glGet with argument
GL_DEPTH_FUNC
glIsEnabled with argument
GL_DEPTH_TEST
SEE ALSO
glDepthRange,
glEnable
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© 1995 Uwe Behrens. All rights reserved.