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Name

glDrawBuffer - specify which color buffers are to be drawn into

C Specification

void glDrawBuffer( GLenum mode ) 


 eqn not supported


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_AUX$i$ = 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(3G)
, glColorMask(3G)
,
glIndexMask(3G)
, glLogicOp(3G)
, glReadBuffer(3G)
 




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