RGBwri(3G)RGBwri(3G)NAME
RGBwri - grants write access to a subset of available bitplanes
FORTRAN SPECIFICATION
subroutine RGBwri(red, green, blue)
integer*4 red, green, blue
PARAMETERS
red expects the mask for the corresponding red bitplanes.
green expects the mask for the corresponding green bitplanes.
blue expects the mask for the corresponding blue bitplanes.
DESCRIPTION
RGBwri sets the red, green, and blue write mask components of the
currently active GL framebuffer, one of normal, popup, overlay, or
underlay as specified by drawmo, to the specified values. The alpha mask
component is set to enable writing to all alpha bitplanes. The current
framebuffer must be in RGB mode for the RGBwri command to be applicable.
All drawing into the color bitplanes of the current framebuffer is masked
by the current write mask. Write mask components are retained in each
draw mode, so when a draw mode is re-entered, the red, green, blue, and
alpha masks are reset to the last values specified in that draw mode.
Each write mask component is an 8-bit mask, which allows changes only to
bitplanes corresponding to ones in the mask. For example,
RGBwri($F0,$00,$00) allows changes only to the 4 most significant bits of
red, and to all the bits of alpha. Bits 8 through 15 of each component
specification are ignored, only bits 0 through 7 are significant.
It is an error to call RGBwri while the current framebuffer is in color
map mode.
The write mask components of all framebuffers in RGB mode are set to $FF
when gconfi is called.
SEE ALSO
drawmo, gRGBma, RGBmod, wmpack
NOTE
On Impact and Infinite Reality individual bits within a component cannot
be masked.
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