glDrawBuffer

specify which color buffers are to be drawn into

Signature

glDrawBuffer( GLenum ( buf ) )-> void
glDrawBuffer( buf )
glDrawBuffers( n , bufs ) 
glDrawBuffers( bufs ) -> bufs

    Wrapper will calculate n from dims of bufs if only
    one argument is provided...
glNamedFramebufferDrawBuffer( GLuint ( framebuffer ) , GLenum ( buf ) )-> void
glNamedFramebufferDrawBuffer( framebuffer , buf )
glNamedFramebufferDrawBuffers( framebuffer , n , bufs )

Parameters

VariablesDescription
framebuffer
Specifies the name of the framebuffer object for glNamedFramebufferDrawBuffer function. Must be zero or the name of a framebuffer object.
buf
For default framebuffer, the argument 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. For framebuffer objects, GL_COLOR_ATTACHMENT$m$ and GL_NONE enums are accepted, where $m$ is a value between 0 and GL_MAX_COLOR_ATTACHMENTS .

Description

When colors are written to the frame buffer, they are written into the color buffers specified by glDrawBuffer . One of the following values can be used for default framebuffer:
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.
For framebuffer objects, GL_COLOR_ATTACHMENT$m$ and GL_NONE enums are accepted, where $m$ is a value between 0 and GL_MAX_COLOR_ATTACHMENTS . glDrawBuffer will set the draw buffer for fragment colors other than zero to GL_NONE .

Errors

GL_INVALID_OPERATION error is generated by glNamedFramebufferDrawBuffer if framebuffer is not zero or the name of an existing framebuffer object.
GL_INVALID_ENUM is generated if buf is not an accepted value.
GL_INVALID_OPERATION is generated if the default framebuffer is affected and none of the buffers indicated by buf exists.
GL_INVALID_OPERATION is generated if a framebuffer object is affected and buf is not equal to GL_NONE or GL_COLOR_ATTACHMENT$m$ , where $m$ is a value between 0 and GL_MAX_COLOR_ATTACHMENTS .

Associated Gets

glGet with argument GL_DRAW_BUFFER

Version Support

glDrawBuffer
glNamedFramebufferDrawBuffer

See Also

glBlendFunc , glColorMask , glDrawBuffers , glLogicOp , glReadBuffer

Copyright

Copyright
1991-2006 Silicon Graphics, Inc. Copyright
2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/
.

Sample Code References

The following code samples have been found which appear to reference the functions described here. Take care that the code may be old, broken or not even use PyOpenGL.

glDrawBuffer
OpenGLContext tests/shadow_2.py Lines: 141, 162
OpenGL-Demo PyOpenGL-Demo/proesch/stereo/stereoDemo.py Lines: 80, 83, 87, 97

Copyright Notices

This documentation is based on documentation licensed under the SGI Free Software License B.