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 com‐
       parison 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  dis‐
       abled.   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