glDepthFunc — specify the value used for depth buffer comparisons
void fsfuncglDepthFunc( | 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.
To enable and disable depth testing, call
glEnable and
glDisable
with argument GL_DEPTH_TEST.
Depth testing is initially disabled.
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.
If depth testing is disabled or no depth buffer exists, it is as if the
depth test always passes.
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.
Copyright © 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.