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Manual Reference Pages  - GLDRAWBUFFER (3G)

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glDrawBuffer - specify which color buffers are to be drawn into

CONTENTS

C Specification
Parameters
Description
Notes
Errors
Associated Gets
See Also

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,  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.

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.

It is always the case that  GL_AUXi =  GL_AUX0 + i.

 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.

 glGet with argument  GL_DRAW_BUFFER
 glGet with argument  GL_AUX_BUFFERS

 glBlendFunc(3G),  glColorMask(3G),  glIndexMask(3G),  glLogicOp(3G),  glReadBuffer(3G)

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