glReadBuffer(3G)	       OpenGL Reference		      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 GL_AUXi, where i is between 0	and
	   GL_AUX_BUFFERS -1.


DESCRIPTION
     glReadBuffer specifies a color buffer as the source for subsequent
     glReadPixels and glCopyPixels commands.  mode accepts one of twelve or
     more predefined values.  (GL_AUX0 through GL_AUX3 are always defined.)
     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.

     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.

     By	default, mode is 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.

     GL_INVALID_OPERATION is generated if glReadBuffer is executed between the
     execution of glBegin and the corresponding	execution of glEnd.

ASSOCIATED GETS
     glGet with	argument GL_READ_BUFFER


SEE ALSO
     glCopyPixels, glDrawBuffer, glReadPixels








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