c(3G)

NAME
     c3f, c3i, c3s, c4f, c4i, c4s - sets the RGB (or RGBA) values for the
     current color vector

C SPECIFICATION
     void c3s(cv)
     short cv[3];

     void c3i(cv)
     long cv[3];

     void c3f(cv)
     float cv[3];

     void c4s(cv)
     short cv[4];

     void c4i(cv)
     long cv[4];

     void c4f(cv)
     float cv[4];

     The subroutines above are functionally the same but declare their
     parameters differently.

PARAMETER
     cv   For the c4 routines, this parameter expects a four element array
          containing RGBA (red, green, blue, and alpha) values.  If you use
          the c3 routines, this parameter expects a three element array
          containing RGB values.

          Array components 0, 1, 2, and 3 are red, green, blue, and alpha,
          respectively. Floating point RGBA values range from 0.0 through 1.0.
          Integer RGBA values range from 0 through 255.  Values that exceed
          the upper limit are clamped to it.  Values that exceed the lower
          limit are not clamped, and therefore result in unpredictable
          operation.

DESCRIPTION
     c4 sets the red, green, blue, and alpha color components of the currently
     active GL framebuffer, one of normal, popup, overlay, or underlay (see
     drawmode).  c3 sets red, green, and blue to the specified values, and
     sets alpha to the maximum value.  The current framebuffer must be in RGB
     mode (see RGBmode) for the c command to be applicable.  Most drawing
     commands copy the current RGBA color components into the color bitplanes
     of the current framebuffer.  Color components are retained in each draw
     mode, so when a draw mode is re-entered, red, green, blue, and alpha are
     reset to the last values specified in that draw mode.
     Integer color component values range from 0, specifying no intensity,
     through 255, specifying maximum intensity.  Floating point color
     component values range from 0.0, specifying no intensity, through 1.0,
     specifying maximum intensity.

     It is an error to call c while the current framebuffer is in color map
     mode.

     The color components of all framebuffers in RGB mode are set to zero when
     gconfig is called.

SEE ALSO
     cpack, drawmode, lmcolor, gRGBcolor

NOTE
     These routines can also be used to modify the current material while
     lighting is active (see lmcolor).  Note that clamping to 1.0 is disabled
     in this case.

     Because only the normal framebuffer currently supports RGB mode, c should
     be called only while draw mode is NORMALDRAW.  Use getgdesc to determine
     whether RGB mode is available in draw mode NORMALDRAW.

BUGS
     On the IRIS-4D/120GTX and IRIS-4D/140GTX, there is problem with the
     graphics DMA hardware that can cause data to be sent to the hardware
     after the subroutine call has returned.  If the data is modified
     immediately after the subroutine call, the modified data may get sent
     down.  To avoid this, don't modify the data until after another n, v, or
     c call has been made.

     This is an example of the bug:

          vertex[2] = 1.0;
          v3f(vertex);   /* 4D/1x0 GTX hardware may receive 3.0 for the z value */
          vertex[2] = 3.0;
          v3f(vertex);


     This is one way to work around the problem:

          vertexA[2] = 1.0;
          v3f(vertexA);
          vertexB[2] = 3.0;
          v3f(vertexB);