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GLHINT(3G)                                                                                        GLHINT(3G)



NAME
       glHint - specify implementation-specific hints


C SPECIFICATION
       void glHint( GLenum target,
                    GLenum mode )


PARAMETERS
       target  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.

       mode    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.  target is a symbolic constant indicating the behavior to be
       controlled, and mode is another symbolic constant indicating the desired behavior. The initial  value
       for each target is GL_DONT_CARE.  mode 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 specified with target, along  with
       suggested semantics, are as follows:

       GL_FOG_HINT         Indicates  the  accuracy of fog calculation.  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_PERSPECTIVE_CORRECTION_HINT
                           Indicates the quality of color and texture coordinate interpolation.  If perspec-tive-corrected perspective-corrected
                           tive-corrected parameter interpolation is not efficiently  supported  by  the  GL
                           implementation,  hinting  GL_DONT_CARE  or GL_FASTEST can result in simple linear
                           interpolation of colors and/or texture coordinates.

       GL_POINT_SMOOTH_HINT
                           Indicates the sampling quality of antialiased points.  If a larger  filter  func-tion function
                           tion  is applied, hinting GL_NICEST can result in more pixel fragments being gen-erated generated
                           erated during rasterization,

       GL_POLYGON_SMOOTH_HINT
                           Indicates the sampling quality of antialiased polygons.   Hinting  GL_NICEST  can
                           result  in more pixel fragments being generated during rasterization, if a larger
                           filter function is applied.

NOTES
       The interpretation of hints depends on the implementation.  Some implementations ignore  glHint  set-tings. settings.
       tings.

ERRORS
       GL_INVALID_ENUM is generated if either target or mode is not an accepted value.

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



                                                                                                  GLHINT(3G)