fglIndexMask(3G)

NAME
     fglIndexMask - control the writing of individual bits in the color index
     buffers


FORTRAN SPECIFICATION
     SUBROUTINE fglIndexMask( INTEGER*4 mask )


PARAMETERS
     mask  Specifies a bit mask to enable and disable the writing of
           individual bits in the color index buffers.  Initially, the mask is
           all 1's.

DESCRIPTION
     fglIndexMask controls the writing of individual bits in the color index
     buffers.  The least significant n bits of mask, where n is the number of
     bits in a color index buffer, specify a mask.  Where a 1 (one) appears in
     the mask, it's possible to write to the corresponding bit in the color
     index buffer (or buffers). Where a 0 (zero) appears, the corresponding
     bit is write-protected.

     This mask is used only in color index mode, and it affects only the
     buffers currently selected for writing (see fglDrawBuffer).  Initially,
     all bits are enabled for writing.

ERRORS
     GL_INVALID_OPERATION is generated if fglIndexMask is executed between the
     execution of fglBegin and the corresponding execution of fglEnd.

ASSOCIATED GETS
     fglGet with argument GL_INDEX_WRITEMASK


SEE ALSO
     fglColorMask, fglDepthMask, fglDrawBuffer, fglIndex, fglIndexPointer,
     fglStencilMask