The glDepthFunc function specifies the value used for depth-buffer comparisons.
void glDepthFunc(
GLenum func
);
| Symbolic Constant | Meaning |
|---|---|
| GL_NEVER | Never passes. |
| GL_LESS | Passes if the incoming z value is less than the stored z value. This is the default 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 glDepthFunc function 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 with the argument GL_DEPTH_TEST.)
Initially, depth testing is disabled.
The following functions retrieve information related to glDepthFunc:
glGet with argument GL_DEPTH_FUNC
glIsEnabled with argument GL_DEPTH_TEST
The following are the error codes generated and their conditions.
| Error Code | Condition |
|---|---|
| GL_INVALID_ENUM | func was not an accepted value. |
| GL_INVALID_OPERATION | glDepthFunc was called between a call to glBegin and the corresponding call to glEnd. |
Windows NT: Use version 3.5 and later.
Windows: Use Windows 95 and later.
Windows CE: Unsupported.
Header: Declared in gl.h.
Import Library: Link with opengl32.lib.
glBegin, glDepthRange, glEnable, glEnd, glGet, glIsEnabled