1GLHINT(3G)                                                          GLHINT(3G)
2
3
4

NAME

6       glHint - specify implementation-specific hints
7
8

C SPECIFICATION

10       void glHint( GLenum target,
11                    GLenum mode )
12
13

PARAMETERS

15       target  Specifies  a  symbolic  constant  indicating the behavior to be
16               controlled.          GL_FOG_HINT,          GL_LINE_SMOOTH_HINT,
17               GL_PERSPECTIVE_CORRECTION_HINT,    GL_POINT_SMOOTH_HINT,    and
18               GL_POLYGON_SMOOTH_HINT are accepted.
19
20       mode    Specifies a symbolic constant indicating the desired  behavior.
21               GL_FASTEST, GL_NICEST, and GL_DONT_CARE are accepted.
22

DESCRIPTION

24       Certain  aspects of GL behavior, when there is room for interpretation,
25       can be controlled with hints.  A hint is specified with two  arguments.
26       target is a symbolic constant indicating the behavior to be controlled,
27       and mode is another symbolic constant indicating the desired  behavior.
28       The  initial value for each target is GL_DONT_CARE.  mode can be one of
29       the following:
30
31       GL_FASTEST          The most efficient option should be chosen.
32
33       GL_NICEST           The most correct, or highest quality, option should
34                           be chosen.
35
36       GL_DONT_CARE        No preference.
37
38       Though  the implementation aspects that can be hinted are well defined,
39       the interpretation of the hints depends  on  the  implementation.   The
40       hint  aspects  that  can be specified with target, along with suggested
41       semantics, are as follows:
42
43       GL_FOG_HINT         Indicates the accuracy of fog calculation.  If per-
44                           pixel  fog calculation is not efficiently supported
45                           by the GL implementation, hinting  GL_DONT_CARE  or
46                           GL_FASTEST  can result in per-vertex calculation of
47                           fog effects.
48
49       GL_LINE_SMOOTH_HINT Indicates  the  sampling  quality  of   antialiased
50                           lines.   If  a  larger  filter function is applied,
51                           hinting GL_NICEST can result in  more  pixel  frag‐
52                           ments being generated during rasterization,
53
54       GL_PERSPECTIVE_CORRECTION_HINT
55                           Indicates  the quality of color and texture coordi‐
56                           nate   interpolation.    If   perspective-corrected
57                           parameter  interpolation  is  not  efficiently sup‐
58                           ported   by   the   GL   implementation,    hinting
59                           GL_DONT_CARE  or  GL_FASTEST  can  result in simple
60                           linear interpolation of colors and/or texture coor‐
61                           dinates.
62
63       GL_POINT_SMOOTH_HINT
64                           Indicates   the  sampling  quality  of  antialiased
65                           points.  If a larger filter  function  is  applied,
66                           hinting  GL_NICEST  can  result in more pixel frag‐
67                           ments being generated during rasterization,
68
69       GL_POLYGON_SMOOTH_HINT
70                           Indicates the sampling quality of antialiased poly‐
71                           gons.   Hinting  GL_NICEST can result in more pixel
72                           fragments being generated during rasterization,  if
73                           a larger filter function is applied.
74

NOTES

76       The interpretation of hints depends on the implementation.  Some imple‐
77       mentations ignore glHint settings.
78

ERRORS

80       GL_INVALID_ENUM is generated  if  either  target  or  mode  is  not  an
81       accepted value.
82
83       GL_INVALID_OPERATION  is  generated  if  glHint is executed between the
84       execution of glBegin and the corresponding execution of glEnd.
85
86
87
88                                                                    GLHINT(3G)