glDepthFunc
The glDepthFunc function specifies the value used for depth-buffer comparisons.
void glDepthFunc(
GLenum func);
Parameters
- func
Specifies the depth-comparison function. The following symbolic constants are accepted.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_LEQUAL Passes if the incoming z value is less than or equal to the stored z value. GL_EQUAL Passes if the incoming z value is 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.
Remarks
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
Error Codes
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. |
Requirements
** Windows NT/2000:** Requires Windows NT 3.5 or later.
** Windows 95/98:** Requires Windows 95 or later. Available as a redistributable for Windows 95.
** Header:** Declared in Gl.h.
** Library:** Use Opengl32.lib.