1991-2006
Silicon Graphics, Inc.
glStencilMask
3G

# glStencilMask

control the front and back writing of individual bits in the stencil planes

## C Specification

                    void glStencilMask
                    GLuint mask

## Parameters

`mask`

  Specifies a bit mask to enable and disable writing of individual bits in the stencil planes. Initially, the mask is all 1's.

## Description

`glStencilMask` controls the writing of individual bits in the stencil planes. The least significant n bits of `mask`, where n is the number of bits in the stencil buffer, specify a mask. Where a 1 appears in the mask, it's possible to write to the corresponding bit in the stencil buffer. Where a 0 appears, the corresponding bit is write-protected. Initially, all bits are enabled for writing.

There can be two separate `mask` writemasks; one affects back-facing polygons, and the other affects front-facing polygons as well as other non-polygon primitives. glStencilMask sets both front and back stencil writemasks to the same values. Use glStencilMaskSeparate to set front and back stencil writemasks to different values.

## Notes

glStencilMask is the same as calling glStencilMaskSeparate with `face` set to `GL_FRONT_AND_BACK`.

## Errors

`GL_INVALID_OPERATION` is generated if `glStencilMask` is executed between the execution of glBegin and the corresponding execution of glEnd.

## Associated Gets

glGet with argument `GL_STENCIL_WRITEMASK`, `GL_STENCIL_BACK_WRITEMASK`, or `GL_STENCIL_BITS`

## See Also

glColorMask, glDepthMask, glIndexMask, glStencilFunc, glStencilFuncSeparate, glStencilMaskSeparate, glStencilOp, glStencilOpSeparate

## Copyright

Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.