cmode(3G)

NAME
     cmode - sets color map mode as the current mode.

C SPECIFICATION
     void cmode()

PARAMETERS
     none

DESCRIPTION
     cmode instructs the system to treat color as a 1-component entity in the
     currently active drawmode.  The single color component is used as an
     index into a table of RGB color values called the color map.  Because
     color map mode is the default value for all GL framebuffers, it can be
     called in any of the framebuffer drawmodes (NORMALDRAW, PUPDRAW,
     OVERDRAW, and UNDERDRAW).  To return the normal framebuffer to color map
     mode, however, you must call cmode while in drawmode NORMALDRAW.  You
     must call gconfig for cmode to take effect.

     While in color map mode, a framebuffer is configured to store a single
     color index at each pixel location.  The framebuffer is displayed by
     continually translating color indices into RGB triples using the
     framebuffer's color map, a table of index-to-RGB mappings.  The red,
     green, and blue components stored in the color map are used (after
     correction for monitor non-linearity) to directly control the color guns
     of the monitor.  Colors and writemasks must be specified using color
     map-compatible commands such as color, colorf, and writemask.

     Many advanced rendering features, such as texture mapping, polygon
     antialiasing, and fog, are available only in RGB mode.  Color map mode
     lighting, while functional, is substantially less robust than its RGB
     mode counterpart.

     Since cmode is the default, you do not have to call it unless the normal
     framebuffer was previously set to RGB mode.

SEE ALSO
     color, drawmode, gconfig, getdisplaymode, getgdesc, multimap, onemap,
     RGBmode, writemask

NOTE
     Color map mode is available in all framebuffers of all hardware
     configurations.  getgdesc can be used to determine how many bitplanes in
     each of the normal, popup, overlay, and underlay framebuffers are
     available in both single and double buffered color map mode.

     This routine is available only in immediate mode.