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, glCopyTexImage1D, glCopyTexImage2D,
	  glCopyTexSubImage1D, glCopyTexSubImage2D, 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.

	  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.

	  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,	glCopyTexImage1D, glCopyTexImage2D,
	  glCopyTexSubImage1D, glCopyTexSubImage2D, glDrawBuffer,
	  glReadPixels