glDrawBuffer - specify which color buffers are to be drawn
into
void glDrawBuffer(GLenum mode);
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.
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.
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.
glGet() with argument GL_DRAW_BUFFER
glBlendFunc(), glColorMask(),
glDrawBuffers(), glLogicOp(), glReadBuffer()
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is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.