- specify implementation-specific hints



C SPECIFICATION


PARAMETERS

       _param1  Specifies  a  symbolic  constant  indicating  the
                behavior  to  be   controlled.    GL_FOG_HINT,
                GL_LINE_SMOOTH_HINT,
                GL_PERSPECTIVE_CORRECTION_HINT,
                GL_POINT_SMOOTH_HINT,  and GL_POLYGON_SMOOTH_HINT
                are accepted.

       _param2  Specifies  a  symbolic  constant  indicating  the
                desired  behavior.   GL_FASTEST,  GL_NICEST,  and
                GL_DONT_CARE are accepted.


DESCRIPTION

       Certain aspects of GL behavior, when  there  is  room  for
       interpretation,  can  be controlled with hints.  A hint is
       specified with two arguments.  _param1 is a symbolic  con-
       stant  indicating  the  behavior  to  be  controlled,  and
       _param2  is  another  symbolic  constant  indicating   the
       desired  behavior.  The  initial value for each _param1 is
       GL_DONT_CARE.  _param2 can be one of the following:

       GL_FASTEST          The most efficient  option  should  be
                           chosen.

       GL_NICEST           The  most correct, or highest quality,
                           option should be chosen.

       GL_DONT_CARE        No preference.

       Though the implementation aspects that can be  hinted  are
       well  defined,  the interpretation of the hints depends on
       the implementation.  The hint aspects that can  be  speci-
       fied  with _param1, along with suggested semantics, are as
       follows:

       GL_FOG_HINT         Indicates the accuracy of fog calcula-
                           tion.  If per-pixel fog calculation is
                           not efficiently supported  by  the  GL
                           implementation,  hinting  GL_DONT_CARE
                           or GL_FASTEST can result in per-vertex
                           calculation of fog effects.

       GL_LINE_SMOOTH_HINT Indicates   the  sampling  quality  of
                           antialiased lines.  If a larger filter
                           function is applied, hinting GL_NICEST
                           can result  in  more  pixel  fragments
                           being generated during rasterization,

                           GL_NICEST  can  result  in  more pixel
                           fragments being generated during  ras-
                           terization,

       GL_POLYGON_SMOOTH_HINT
                           Indicates   the  sampling  quality  of
                           antialiased     polygons.      Hinting
                           GL_NICEST  can  result  in  more pixel
                           fragments being generated during  ras-
                           terization,  if  a larger filter func-
                           tion is applied.


NOTES

       The interpretation of hints depends on the implementation.
       Some implementations ignore glHint settings.


ERRORS

       GL_INVALID_ENUM  is generated if either _param1 or _param2
       is not an accepted value.

       GL_INVALID_OPERATION is generated if  glHint  is  executed
       between  the  execution  of  glBegin and the corresponding
       execution of glEnd.



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