backbuffer(3G)backbuffer(3G)NAME
backbuffer, frontbuffer - enable and disable drawing to the back or front
buffer
C SPECIFICATION
void backbuffer(Boolean b)
void frontbuffer(Boolean b)
PARAMETERS
b is either TRUE or FALSE.
TRUE enables updating in the back/front bitplane buffer.
FALSE disables updating in the back/front bitplane buffer.
DESCRIPTION
The GL supports four separate framebuffers: pop-up, overlay, underlay,
and normal. Three of these framebuffers, overlay, underlay, and normal,
can be configured in double buffer mode. When so configured, a
framebuffer includes two color bitplane buffers: one visible bitplane
buffer, called the front buffer, and one non-visible bitplane buffer,
called the back buffer. The commands swapbuffers and mswapbuffers
interchange the front and back buffer assignments.
By default, when a framebuffer is configured in double buffer mode,
drawing is enabled in the back buffer, and disabled in the front buffer.
frontbuffer and backbuffer enable and disable drawing into the front and
back buffers, allowing the default to be overriden. It is acceptable to
enable neither front nor back, either front or back, or both front and
back simultaneously. Note, for example, that z-buffer drawing continues
to update the z-buffer with depth values when neither the front buffer
nor the back buffer is enabled for drawing.
frontbuffer and backbuffer state is maintained separately for each of the
overlay, underlay, and normal framebuffers. Calls to these routines
affect the framebuffer that is currently active, based on the current
drawmode.
backbuffer is ignored when the currently active framebuffer is in single
buffer mode. frontbuffer is also ignored when the currently active
framebuffer is in single buffer mode, unless zdraw is enabled for that
framebuffer (see zdraw).
After each call to gconfig, backbuffer is enabled and frontbuffer is
disabled.
SEE ALSO
drawmode, doublebuffer, getbuffer, gconfig, singlebuffer, swapbuffers,
zdraw, rightbuffer, leftbuffer
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backbuffer(3G)backbuffer(3G)NOTE
IRIS-4D G, GT, and GTX models, the Personal Iris, Indigo Entry, Indy, XL,
XS, XS24, XZ, Elan and Extreme systems do not support double buffer
operation in the overlay and underlay framebuffers. IRIS-4D
RealityEngine model does not support double buffer operation in the
underlay framebuffer.
At most four color buffers, such as front-left, front-right, back-left,
back-right, and zdraw, can be rendered into simultaneously on the IRIS-4D
RealityEngine model.
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