lshaderange(3G)

NAME
     lshaderange - sets range of color indices used for depth-cueing

C SPECIFICATION
     void lshaderange(lowin, highin, znear, zfar)
     Colorindex lowin, highin;
     long znear, zfar;

PARAMETERS
     lowin    expects the low-intensity color map index.

     highin   expects the high-intensity color map index.

     znear    expects the nearer screen z, to which highin is mapped.

     zfar     expects the farther screen z, to which lowin is mapped.

DESCRIPTION
     lshaderange sets the range of color indices used for depth-cueing.  The
     screen z range [znear, zfar] is mapped linearly into the color index
     range [highin, lowin].  Screen z values nearer than znear map to highin;
     screen z values farther than zfar map to lowin.

     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.  The default
     is lshaderange(0, 7, Zmin, Zmax), where Zmin and Zmax are the values such
     that the full range supported by the graphics hardware is used.

     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.