GLDRAWBUFER(3G)                                              GLDRAWBUFER(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 GLNONE, GLFRONTLEFT,  GLFRONTRIGHT,  GLBACKLEFT,
             GLBACKRIGHT,     GLFRONT,    GLBACK,    GLEFT,    GLRIGHT,
             GLFRONTANDBACK, and GLAUXi, where i is between 0 and
             ``GLAUXBUFERS'' -1, are accepted (GLAUXBUFERS  is  not  the
             upper  limit;  use  glGet  to  query  the number of available aux
             buffers.)  The initial value is GLFRONT for single-buffered con-
             texts, and GLBACK 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:

       GLNONE                  No color buffers are written.

       GLFRONTLEFT            Only the front left color buffer is written.

       GLFRONTRIGHT           Only  the front right color buffer is written.

       GLBACKLEFT             Only the back left color buffer is written.

       GLBACKRIGHT            Only the back right color buffer is written.

       GLFRONT                 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.

       GLBACK                  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.

       GLEFT                  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.

       GLRIGHT                 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.

       GLFRONTANDBACK        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.

       GLAUXi                  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  con-
       texts  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.

NOTES
       It is always the case that GLAUXi = GLAUX00 ] i.

ERORS
       GLINVALIDENUM is generated if mode is not an accepted value.

       GLINVALIDOPERATION is generated if none of the buffers  indicated  by
       mode exists.

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

ASOCIATED GETS
       glGet with argument GLDRAWBUFER
       glGet with argument GLAUXBUFERS

SEE ALSO
       glBlendFunc, glColorask, glIndexask, glLogicOp, glReadBuffer



                                                              GLDRAWBUFER(3G)