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gldrawbuffer(3g) [redhat man page]

GLDRAWBUFFER(3G)														  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, 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.

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  buf-
				fers, 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 ini-
       tialization.

NOTES

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

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.

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

ASSOCIATED GETS

       glGet with argument GL_DRAW_BUFFER
       glGet with argument GL_AUX_BUFFERS

SEE ALSO

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

																  GLDRAWBUFFER(3G)

Check Out this Related Man Page

GLREADBUFFER(3G)														  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, glCopyTexImage1D,  glCopyTexImage2D,  glCopyTexSubImage1D,
       glCopyTexSubImage2D,  glCopyTexSubImage3D,  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, glCopyTexSubImage3D, glDrawBuffer, glReadPixels

																  GLREADBUFFER(3G)
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