- 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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