glreadbuffer(3g) [centos man page]

GLREADBUFFER(3G)						   OpenGL Manual						  GLREADBUFFER(3G)

NAME

       glReadBuffer - select a color buffer source for pixels

C SPECIFICATION

       void glReadBuffer(GLenum mode);

PARAMETERS

       mode
	   Specifies a color buffer. Accepted values are GL_FRONT_LEFT, GL_FRONT_RIGHT, GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT, GL_BACK, GL_LEFT,
	   GL_RIGHT, and the constants GL_COLOR_ATTACHMENTi.

DESCRIPTION

       glReadBuffer specifies a color buffer as the source for subsequent glReadPixels(), glCopyTexImage1D(), glCopyTexImage2D(),
       glCopyTexSubImage1D(), glCopyTexSubImage2D(), and glCopyTexSubImage3D() commands.  mode accepts one of twelve or more predefined values. In
       a fully configured system, GL_FRONT, GL_LEFT, and GL_FRONT_LEFT all name the front left buffer, GL_FRONT_RIGHT and GL_RIGHT name the front
       right buffer, and GL_BACK_LEFT and GL_BACK name the back left buffer. Further more, the constants GL_COLOR_ATTACHMENTi may be used to
       indicate the ith color attachment where i ranges from zero to the value of GL_MAX_COLOR_ATTACHMENTS minus one.

       Nonstereo double-buffered configurations have only a front left and a back left buffer. Single-buffered configurations have a front left
       and a front right buffer if stereo, and only a front left buffer if nonstereo. It is an error to specify a nonexistent buffer to
       glReadBuffer.

       mode is initially GL_FRONT in single-buffered configurations and GL_BACK in double-buffered configurations.

ERRORS

       GL_INVALID_ENUM is generated if mode is not one of the twelve (or more) accepted values.

       GL_INVALID_OPERATION is generated if mode specifies a buffer that does not exist.

ASSOCIATED GETS

       glGet() with argument GL_READ_BUFFER

SEE ALSO

       glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glDrawBuffer(), glReadPixels()

COPYRIGHT

       Copyright (C) 1991-2006 Silicon Graphics, Inc. Copyright (C) 2011 Khronos Group. This document is licensed under the SGI Free Software B
       License. For details, see http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							  GLREADBUFFER(3G)

GLDRAWBUFFER(3G)						  [FIXME: manual]						  GLDRAWBUFFER(3G)

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, 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

       glBlendFunc(), glColorMask(), glDrawBuffers(), glLogicOp(), glReadBuffer()

COPYRIGHT

       Copyright (C) 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/.

[FIXME: source] 						    05/30/2012							  GLDRAWBUFFER(3G)