NAME    [Toc]    [Back]

       glDepthFunc - specify the value used for depth buffer comparisons

SYNOPSIS    [Toc]    [Back]

       void glDepthFunc(
               GLenum func );

PARAMETERS    [Toc]    [Back]

       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    [Toc]    [Back]

       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:  Never
       passes.   Passes  if the incoming depth value is less than
       the stored depth value.   Passes  if  the  incoming  depth
       value  is  equal to the stored depth value.  Passes if the
       incoming depth value is less than or equal to  the  stored
       depth  value.   Passes  if  the  incoming  depth  value is
       greater than the stored depth value.  Passes if the incoming
  depth  value  is not equal to the stored depth value.
       Passes if the incoming depth  value  is  greater  than  or
       equal to the stored depth value.  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    [Toc]    [Back]

       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    [Toc]    [Back]

       glGet() with argument GL_DEPTH_FUNC
       glIsEnabled() with argument GL_DEPTH_TEST

SEE ALSO    [Toc]    [Back]

       glDepthRange(3)(), glEnable(3), glPolygonOffset(3)



                                                  glDepthFunc(3G)