glDrawBuffer(3G) OpenGL Reference glDrawBuffer(3G)
NAME
glDrawBuffer - specify which color buffers are to be drawn into
C SPECIFICATION
void glDrawBuffer( GLenum mode )
PARAMETERS
mode Specifies up to four color buffers to be drawn into. The following
symbolic constants are accepted: GLNONE, GLFRONTLEFT,
GLFRONTRIGHT, GLBACKLEFT, GLBACKRIGHT, GLFRONT, GLBACK,
GLLEFT, GLRIGHT, GLFRONTANDBACK, and GLAUXi, where i ranges
from zero to the number of auxiliary color buffers minus one. Use
glGetIntegerv with argument GLAUXBUFFERS to determine the number
of auxiliary color buffers for the current context.
The default value of mode is GLFRONT for single-buffered contexts,
and GLBACK for double-buffered contexts.
DESCRIPTION
When colors are written to the frame buffer, they are written into the
color buffers specified by glDrawBuffer. The specifications are as
follows:
GLNONE No color buffers are written.
GLFRONTLEFT Only the front left color buffer is written.
GLFRONTRIGHT Only the front right color buffer is written.
GLBACKLEFT Only the back left color buffer is written.
GLBACKRIGHT Only the back right color buffer is written.
GLFRONT Only the front left and front right color
buffers are written. If there is no front right
color buffer, only the front left color buffer
is written.
GLBACK Only the back left and back right color buffers
are written. If there is no back right color
buffer, only the back left color buffer is
written.
GLLEFT Only the front left and back left color buffers
are written. If there is no back left color
buffer, only the front left color buffer is
written.
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glDrawBuffer(3G) OpenGL Reference glDrawBuffer(3G)
GLRIGHT Only the front right and back right color
buffers are written. If there is no back right
color buffer, only the front right color buffer
is written.
GLFRONTANDBACK All the front and back color buffers (front
left, front right, back left, back right) are
written. If there are no back color buffers,
only the front left and front right color
buffers are written. If there are no right
color buffers, only the front left and back left
color buffers are written. If there are no
right or back color buffers, only the front left
color buffer is written.
GLAUXi Only auxiliary color buffer i is written.
If more than one color buffer is selected for drawing, then blending or
logical operations are computed and applied independently for each color
buffer and can produce different results in each buffer.
Monoscopic contexts include only left buffers, and stereoscopic contexts
include both left and right buffers. Likewise, single-buffered contexts
include only front buffers, and double-buffered contexts include both
front and back buffers. The context is selected at GL initialization.
NOTES
It is always the case that GLAUXi = GLAUX0 + i.
ERRORS
GLINVALIDENUM is generated if mode is not an accepted value.
GLINVALIDOPERATION is generated if none of the buffers indicated by
mode exists.
GLINVALIDOPERATION is generated if glDrawBuffer is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GLDRAWBUFFER
glGet with argument GLAUXBUFFERS
SEE ALSO
glBlendFunc, glColorMask, glIndexMask, glLogicOp, glReadBuffer
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