glflush(3g) [xfree86 man page]

GLFLUSH(3G)															       GLFLUSH(3G)

NAME

       glFlush - force execution of GL commands in finite time

C SPECIFICATION

       void glFlush( void )

DESCRIPTION

       Different GL implementations buffer commands in several different locations, including network buffers and the graphics accelerator itself.
       glFlush empties all of these buffers, causing all issued commands to be executed as quickly as they are accepted by  the  actual  rendering
       engine.	Though this execution may not be completed in any particular time period, it does complete in finite time.

       Because any GL program might be executed over a network, or on an accelerator that buffers commands, all programs should call glFlush when-
       ever they count on having all of their previously issued commands completed.  For example, call glFlush before waiting for user input  that
       depends on the generated image.

NOTES

       glFlush can return at any time.	It does not wait until the execution of all previously issued GL commands is complete.

ERRORS

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

SEE ALSO

       glFinish(3G)

																       GLFLUSH(3G)

GLXSWAPBUFFERS()														  GLXSWAPBUFFERS()

NAME

       glXSwapBuffers - exchange front and back buffers

C SPECIFICATION

       void glXSwapBuffers( Display *dpy,
			    GLXDrawable drawable )

       delim $$

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 immedi-
       ately after glXSwapBuffers is called.

       glXSwapBuffers performs an implicit glFlush before it returns.  Subsequent OpenGL commands may be issued immediately after calling glXSwap-
       Buffers, 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 pbuffers as well as windows.

       All GLX rendering contexts share the same notion of which are front buffers and which are back buffers.	One consequence is that when  mul-
       tiple  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 current context of the
       calling thread, and drawable identifies a window that is no longer valid.

SEE ALSO

       glFlush, glXBindSwapBarrierSGIX, glXJoinSwapGroupSGIX, glXSwapIntervalSGI

																  GLXSWAPBUFFERS()