xfree86 man page for gldepthfunc

GLDEPTHFUNC(3G) 														   GLDEPTHFUNC(3G)

NAME
       glDepthFunc - specify the value used for depth buffer comparisons

C SPECIFICATION
       void glDepthFunc( GLenum func )

PARAMETERS
       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.

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.	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.

ERRORS
       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.

ASSOCIATED GETS
       glGet with argument GL_DEPTH_FUNC
       glIsEnabled with argument GL_DEPTH_TEST

SEE ALSO
       glDepthRange(3G), glEnable(3G), glPolygonOffset(3G)

																   GLDEPTHFUNC(3G)