glXSwapBuffers - exchange front and back buffers



C SPECIFICATION

       void glXSwapBuffers( Display *dpy,
                            GLXDrawable drawable )



PARAMETERS

       dpy       Specifies the connection to the X server.

       drawable  Specifies  the  drawable whose buffers are to be
                 swapped.


DESCRIPTION

       glXSwapBuffers promotes the contents of the back buffer of
       drawable  to  become  the  contents of the front buffer of
       drawable.  The contents of the  back  buffer  then  become
       undefined.   The  update  typically takes place during the
       vertical retrace of the monitor, rather  than  immediately
       after glXSwapBuffers is called.

       glXSwapBuffers  performs  an  implicit  glFlush  before it
       returns.  Subsequent OpenGL commands may be issued immedi-
       ately  after  calling glXSwapBuffers, but are not executed
       until the buffer exchange is completed.

       If drawable was not created  with  respect  to  a  double-
       buffered  visual,  glXSwapBuffers  has  no  effect, and no
       error is generated.


NOTES

       The contents of the back buffer become undefined  after  a
       swap.  Note  that this applies to pixel buffers as well as
       windows.

       All GLX rendering contexts share the same notion of  which
       are  front buffers and which are back buffers.  One conse-
       quence is that when multiple clients are rendering to  the
       same  double-buffered  window,  all  of them should finish
       rendering before one of them issues the  command  to  swap
       buffers.   The  clients  are  responsible for implementing
       this synchronization.  Typically this is  accomplished  by
       executing  glFinish  and  then using a semaphore in shared
       memory to rendezvous before swapping.


ERRORS

       GLXBadDrawable is generated if drawable is not a valid GLX
       drawable.

       GLXBadCurrentWindow  is  generated if dpy and drawable are
       respectively the display and drawable associated with  the