On Fri, 24 Mar 2006, Florent Monnier wrote: > > > > You can render to a pixmap and then copy the contents of the > > > > pixmap to the window with XCopyArea(). > ... > > > 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 (to clear out > > the existing videoram pixmaps) before starting your app does it > > run significantly faster? > > Not at all. > It is still very slow in the same way. I'm not sure why it's doing that. If the pixmap was in videoram, for the worst case (if it were framebuffer bandwidth limited), I would expect double buffered to be 1/3 the speed of single buffered. The only reasons I can think of why it wouldn't go into videoram are: 1) Not enough videoram (seems unlikely with that card just after a VT switch). 2) It's a shared memory pixmap rather than regular pixmap created with XCreatePixmap. 3) You're doing more than just rendering to the pixmap and copying into the window. I have a old demo app which does something similar. http://www.xfree86.org/~mvojkovi/skull.tar.gz Don't run the DGA version (DGA is mostely obsolete). Run the X11 version ("make skull_X"). Mark. _______________________________________________ XFree86 mailing list XFree86@xxxxxxxxxxx http://XFree86.Org/mailman/listinfo/xfree86
