swritemask(3G) 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.
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