NAME
        SetRGB32 -- Set one color register for this Viewport. (V39)

   SYNOPSIS
        SetRGB32(  vp,  n,   r,    g,    b)
                   a0  d0   d1    d2    d3

        void SetRGB32( struct viewport *, ulong, ulong, ulong, ulong );

   INPUTS
        vp = viewport
        n = the number of the color register to set.
        r = red level   (32 bit left justified fraction)
        g = green level (32 bit left justified fraction)
        b = blue level  (32 bit left justified fraction)

   RESULT
        If there is a colormap for this viewport, then the value will
        be stored in the colormap.
        The selected color register is changed to match your specs.
        If the color value is unused then nothing will happen.

   BUGS

   NOTES
        Lower order bits of the palette specification will be discarded,
        depending on the color palette resolution of the target graphics
        device. Use 0xffffffff for the full value, 0x7fffffff for 50%,
        etc. You can find out the palette range for your screen by
        querying the graphics data base.

   SEE ALSO
        getcolormap() getrgb32() setrgb32cm() loadrgb32() graphics/view.h