1991-2006
Silicon Graphics, Inc.
glDrawBuffer
3G
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.
Symbolic constants
GL_NONE,
GL_FRONT_LEFT,
GL_FRONT_RIGHT,
GL_BACK_LEFT,
GL_BACK_RIGHT,
GL_FRONT,
GL_BACK,
GL_LEFT,
GL_RIGHT, and
GL_FRONT_AND_BACK
are accepted.
The initial value is GL_FRONT for single-buffered contexts,
and GL_BACK 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:
GL_NONE
No color buffers are written.
GL_FRONT_LEFT
Only the front left color buffer is written.
GL_FRONT_RIGHT
Only the front right color buffer is written.
GL_BACK_LEFT
Only the back left color buffer is written.
GL_BACK_RIGHT
Only the back right color buffer is written.
GL_FRONT
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.
GL_BACK
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.
GL_LEFT
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.
GL_RIGHT
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.
GL_FRONT_AND_BACK
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.
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.
Errors
GL_INVALID_ENUM is generated if mode is not an accepted value.
GL_INVALID_OPERATION is generated if none of the buffers indicated
by mode exists.
Associated Gets
glGet with argument GL_DRAW_BUFFER
See Also
glBlendFunc,
glColorMask,
glDrawBuffers,
glLogicOp,
glReadBuffer
Copyright
Copyright 1991-2006
Silicon Graphics, Inc. This document is licensed under the SGI
Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.