glReadBuffer.3gl




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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Last Edited: Mon, May 22, 1995

AFV