Re: double buffer

[Florent Monnier <fmonnier@xxxxxxxxxxxxxxxxxxxxxx>]

> > >    You can render to a pixmap and then copy the contents of the
> > > pixmap to the window with XCopyArea().  This will be similar to
> > > many implementations of glXSwapBuffers, however, many GL implementation
> > > allow synchronization with the refresh rate, while Xlib offers no
> > > such feature.  Note that glXSwapBuffers executes an implicit
> > > glFlush, while XCopyArea does not execute an implicit XFlush.
> >
> > Thanks a lot!
> >
> > It works, but there is a big big loss of performence !
> >
> > Without double buffer the frame rate can be for a test example
> >   380 frames per seconds,
> > but with double-buffer it slows a lot down to
> >   30 frames / seconds.
>
>    That sounds like the pixmap didn't get put in videoram, which
> is unfortunate.  It probably would have been fast if the pixmap
> was in videoram.  Does this card have very much videoram?

My video card is a nVidia  GeForce4 Ti 4200 with AGP8X

> If you VT switch to the console and then back to X

Sorry, I'm not sure to understand,
 What is VT ?

> (to clear out the existing videoram pixmaps) before starting your app does
> it run significantly faster?

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