GLAPI/glDrawBuffer

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glDrawBuffer
Core in version 4.4
Core since version 1.0

glDrawBuffer: specify which color buffers are to be drawn into

Function Definition

 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.

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

glBindFramebuffer, glBlendFunc, glColorMask, glDrawBuffers, glLogicOp

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/.