specify the value used for depth buffer comparisons
Signature
Parameters
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
.)
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 if no
depth buffer exists, it is as if the depth test always passes.
Notes
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. In order to
unconditionally write to the depth buffer, the depth test should be enabled
and set to
GL_ALWAYS
.
Errors
GL_INVALID_ENUM
is generated if
func
is not an accepted value.
See Also
Copyright
Copyright
1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/
.
Sample Code References
The following code samples have been found which appear to reference the functions described here. Take care that the code may be old, broken or not even use PyOpenGL.
glDepthFunc
{LGPL or GPL or MPL} Kamaelia
Sketches/CL/Topology3D/THF/Kamaelia/UI/OpenGL/OpenGLDisplay.py
Lines: 461
{LGPL or GPL or MPL} Kamaelia
Sketches/CL/Topology3D/THF/Sketches/playground/Display3D.py
Lines: 146
{LGPL or GPL or MPL} Kamaelia
Sketches/THF/Packages/Kamaelia/Community/THF/Kamaelia/UI/OpenGL/OpenGLDisplay.py
Lines: 461