void GLAPIENTRY glIndexMask( GLuint mask )

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

DESCRIPTION
       glIndexMask 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  corre‐
       sponding bit is write-protected.

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

ERRORS
       GL_INVALID_OPERATION is generated if glIndexMask is executed between the
       execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS
       glGet with argument GL_INDEX_WRITEMASK

SEE ALSO
       glColorMask,   glDepthMask,   glDrawBuffer,   glIndex,   glIndexPointer,
       glStencilMask

                                                                GLINDEXMASK(3G)