zbsize(3G) zbsize(3G)
NAME
zbsize - specifies the number of bit planes desired to comprise the Z
buffer
C SPECIFICATION
void zbsize(long planes)
PARAMETERS
planes is the number of bit planes requested to be configured as Z
buffer planes. Only positive values are accepted. The default
is machine dependent, usually 24 or 32.
DESCRIPTION
zbsize specifies how many bit planes are requested to be configured as Z
buffer planes. The constraints on planes are machine dependent. Call
getgdesc(GDBITSNORMZBUFFER) to determine the maximum number of bit
planes available for Z buffer operation.
zbsize takes effect only after gconfig has been called. The number of
bit planes granted for the Z buffer may not be exactly what was
requested. Call getgconfig(GCBITSZBUFFER) to determine how many bit
planes were configured as Z buffer planes.
Since Z buffer bit planes are available only in the normal framebuffer,
zbsize should be called only while draw mode is NORMALDRAW.
SEE ALSO
gconfig, getgconfig, getgdesc, mssize
NOTES
This routine is available only in immediate mode.
Since most machines support only a finite set of Z buffer sizes, planes
is rounded to the nearest supported size.
IRIS-4D G, GT, GTX, VGX, and VGXT models, the Personal Iris, Iris Indy,
Indigo Entry, XL, XS, XS24, XZ, Elan and Extreme systems do not support
zbsize.
The IRIS-4D RealityEngine models support only values of 0, 24 or 32
planes. On these models the Z buffer and the depth component in the
multisample buffer are independent. When the multisample buffer is
requested in the current framebuffer configuration, it is recommended to
call zbsize(0), as no Z buffer planes are required.
BUGS
On the IRIS-4D RealityEngine models the framebuffer cannot be configured
to consist of 32 Z buffer planes (or 32 depth planes in the multisample
buffer) and 8 color planes for each of the RGB color buffers
simultaneously.
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