glutGameModeString  - sets the game mode configuration via
a string.

glutGameModeString
	glutGameModeString(string) -> None

void glutGameModeString(const char *string);

string    ASCII string for selecting a game mode  configu-
          ration.

glutGameModeString sets the game mode configuration via an
ASCII string.  The  game  mode  configuration  string  for
GLUT's  fullscreen game mode describes the suitable screen
width and height in pixels, the pixel depth in  bits,  and
the  video refresh frequency in hertz.  The game mode con-
figuration string can also specify a window system  depen-
dent display mode.

The  string  is a list of zero or more capability descrip-
tions seperated  by  spaces  and  tabs.   Each  capability
description  is  a  capability  name that is followed by a
comparator and a numeric value.  (Unlike the display  mode
string specified using glutInitDisplayString, the compara-
tor and numeric value are  not  optional.)   For  example,
"width>=640" and "bpp=32" are both valid criteria.

The  capability  descriptions are translated into a set of
criteria used to select the appropriate game mode configu-
ration.

The  criteria are matched in strict left to right order of
precdence.  That is, the first specified  criteria  (left-
most)  takes  precedence  over the later criteria for non-
exact criteria (greater than,  less  than,  etc.  compara-
tors).   Exact criteria (equal, not equal compartors) must
match exactly so precedence is not relevant.

The numeric value is an integer that is  parsed  according
to  ANSI  C's strtol(str, strptr, 0) behavior.  This means
that decimal, octal (leading 0),  and  hexidecimal  values
(leading 0x) are accepeted.

The valid compartors are:

=       Equal.

!=      Not equal.

<       Less  than  and  preferring larger difference (the
        least is best).

>       Greater than  and  preferring  larger  differences

        (the most is best).

<=      Less  than  or equal and preferring larger differ-
        ence (the least is best).

>=      Greater than or equal and preferring more  instead
        of less.  This comparator is useful for allocating
        resources like color precsion or depth buffer pre-
        cision  where  the  maximum  precison is generally
        preferred.  Contrast with the tilde (~) comprator.

~       Greater  than or equal but preferring less instead
        of more.  This compartor is useful for  allocating
        resources  such as stencil bits or auxillary color
        buffers where you would rather not over  allocate.

The valid capability names are:

bpp     Bits per pixel for the frame buffer.

height  Height of the screen in pixels.

hertz   Video refresh rate of the screen in hertz.

num     Number  of  the  window  system depenedent display
        mode configuration.

width   Width of the screen in pixels.

An additional compact screen resolution description format
is   supported.   This  compact  description  convienently
encodes the screen  resolution  description  in  a  single
phrase.   For  example,  "640x480:16@60" requests a 640 by
480 pixel screen with 16 bits per  pixel  at  a  60  hertz
video  refresh rate.  A compact screen resolution descrip-
tion can be mixed with  conventional  capability  descrip-
tions.

The  compact  screen  resolution  description format is as
follows:

[ width "x" height ][ ":" bitsPerPixel ][ "@" videoRate ]

Unspecifed capability descriptions will result in unspeci-
fied criteria being generated.  These unspecified criteria
help glutGameModeString behave sensibly  with  terse  game
mode description strings.

glutGameModeGet,   glutEnterGameMode,   glutLeaveGameMode,
glutInitDisplayString

Mark J. Kilgard (mjk@nvidia.com)