glHint
NAME
glHint -- specify implementation-specific hints
C SPECIFICATION
void glHint(GLenum target,
GLenum mod)
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.
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
-
The client doesn't have a 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. Hinting
GL_NICEST can result in more pixel fragments being generated
during rasterization, if a larger filter function is applied.
- GL_PERSPECTIVE_CORRECTION_HINT
-
Indicates the quality of color and texture coordinate interpolation.
If perspective-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. Hinting
GL_NICEST can result in more pixel fragments being generated
during rasterization, if a larger filter function is applied.
- 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. glHint can
be ignored.
ERRORS
GL_INVALID_ENUM is generated if target or mode is not an
accepted value.
GL_INVALID_OPERATION is generated if glHint is called between
a call to glBegin and the corresponding
call to glEnd.
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© 1995 Uwe Behrens. All rights reserved.