OpenGL man pages
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 default value is GL_LESS.
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
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
GL_EQUAL Passes if the incoming z value is equal to the stored z
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
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
Fri Dec 6 11:18:03 EST 1996
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