'\"! eqn | mmdoc
'\"macro stdmacro
.ds Vn Version 1.2
.ds Dt 6 March 1997
.ds Re Release 1.1.0
.ds Dp Mar 17 18:06
.ds Dm  Mar  6 20:0
.ds Xs 56729 3 indexmask.gl
.TH GLINDEXMASK
.SH NAME
.B "glIndexMask
\- control the writing of individual bits in the color index buffers

.SH C SPECIFICATION
void \f3glIndexMask\fP(
GLuint \fImask\fP )
.nf
.fi

.EQ
delim $$
.EN
.SH PARAMETERS
.TP \w'\f2mask\fP\ \ 'u 
\f2mask\fP
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.
.SH DESCRIPTION
\f3glIndexMask\fP controls the writing of individual bits in the color index buffers.
The least significant $n$ bits of \f2mask\fP,
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.
.P
This mask is used only in color index mode,
and it affects only the buffers currently selected for writing
(see \f3glDrawBuffer\fP).
Initially, all bits are enabled for writing.
.SH ERRORS
\f3GL_INVALID_OPERATION\fP is generated if \f3glIndexMask\fP
is executed between the execution of \f3glBegin\fP
and the corresponding execution of \f3glEnd\fP.
.SH ASSOCIATED GETS
\f3glGet\fP with argument \f3GL_INDEX_WRITEMASK\fP
.SH SEE ALSO
\f3glColorMask\fP,
\f3glDepthMask\fP,
\f3glDrawBuffer\fP,
\f3glIndex\fP,
\f3glIndexPointer\fP,
\f3glStencilMask\fP