swritemask(3G)

NAME
     swritemask - specify which stencil bits can be written

C SPECIFICATION
     void swritemask(mask)
     unsigned long mask;

PARAMETERS
     mask   expects a mask whose least-significant bits are used to control
            writing of the stencil bitplanes.  Bitplanes corresponding to 1's
            in the mask can be written, those corresponding to 0's are read-
            only.

DESCRIPTION
     swritemask specifies which of the stencil bitplanes are written both
     during normal stencil operation and stencil clear (see sclear).  Bits 0
     through planes-1 are significant, where planes is the current size of the
     stencil buffer.

     Because only the normal framebuffer includes stencil bitplanes,
     swritemask should be called only while draw mode is NORMALDRAW.

     swritemask is initialized when a window is created, and when gconfig is
     called, to enable all stencil bitplanes.

SEE ALSO
     drawmode, gconfig, sclear, stencil, stensize

NOTES
     IRIS-4D G, GT, and GTX models, as well as the Personal Iris, Indy, Iris
     Indigo Entry and XL, do not support stencil bitplanes, and therefore do
     not support swritemask.  Use getgdesc to determine whether stencil
     bitplanes are supported.