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.
Symbolic constants GL_NONE, GL_FRONT_LEFT,
GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT,
GL_BACK, GL_LEFT, GL_RIGHT, GL_FRONT_AND_BACK, and
GL_AUXi, where i is between 0 and ``GL_AUX_BUFFERS''
-1, are accepted (GL_AUX_BUFFERS is not the upper
limit; use glGet to query the number of available aux
buffers.) 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.
GL_AUXi 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 GL_AUXi = GL_AUX0 + i.
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.
GL_INVALID_OPERATION is generated if glDrawBuffer is
executed between the execution of glBegin and the
corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_DRAW_BUFFER
glGet with argument GL_AUX_BUFFERS
SEE ALSO
glBlendFunc, glColorMask, glIndexMask, glLogicOp,
glReadBuffer