lRGBrange(3G)

NAME
     lRGBrange - sets the range of RGB colors used for depth-cueing

C SPECIFICATION
     void lRGBrange(rmin, gmin, bmin, rmax, gmax, bmax, znear, zfar)
     short rmin, gmin, bmin, rmax, gmax, bmax;
     long znear, zfar;

PARAMETERS
     rmin   expects the minimum value to be stored in the red bitplanes.

     gmin   expects the minimum value to be stored in the green bitplanes.

     bmin   expects the minimum value to be stored in the blue bitplanes.

     rmax   expects the maximum value to be stored in the red bitplanes.

     gmax   expects the maximum value to be stored in the green bitplanes.

     bmax   expects the maximum value to be stored in the blue bitplanes.

     znear  expects the nearer screen z, to which the maximum colors are
            mapped.

     zfar   expects the farther screen z, to which the minimum colors are
            mapped.

DESCRIPTION
     lRGBrange sets the range of RGB colors used for depth-cueing in RGB mode.
     The screen z range [znear, zfar] is mapped linearly into the RGB color
     range [ (rmax,gmax,bmax), (rmin,gmin,bmin) ].  Screen z values nearer
     than znear are mapped to (rmax,gmax,bmax); screen z values farther than
     zfar are mapped to (rmin,gmin,bmin).

     The valid range for znear and zfar depends on the state of the
     GLC_ZRANGEMAP compatibility mode (see glcompat).  If it is 0, the valid
     range depends on the graphics hardware.  When multisample is enabled, and
     multisample buffers exist in the current framebuffer configuration in the
     current drawmode, the minimum is the value returned by
     getgconfig(GC_MS_ZMIN) and the maximum is the value returned by
     getgconfig(GC_MS_ZMAX).  Otherwise, the minimum is the value returned by
     getgconfig(GC_ZMIN) and the maximum is the value returned by
     getgconfig(GC_ZMAX).  If the state of the GLC_ZRANGEMAP compatibility
     mode is 1, the minimum is 0x0 and the maximum is 0x7FFFFF.  Znear and
     zfar should be chosen to be consistent with the near and far parameters
     passed to lsetdepth.  If near < far, then znear should be less than zfar.
     If near > far, then znear should be greater than zfar.  In either case,
     the range [near, far] should bound the range [znear, zfar].
SEE ALSO
     depthcue, getgdesc, glcompat, lsetdepth

NOTE
     When using this routine, you should always explicitly set the
     GLC_ZRANGEMAP mode of glcompat because its default is different on
     different models.