Netbooks... really slow with OGL... can someone help me with a solution?

Clemens Eisserer linuxhippy at
Thu Oct 29 11:40:55 PDT 2009


> I am a game programmer, and I live in a country where normal computer has
> configurations that remember netbooks (like having VIA or SIS chipsets...).
> Because of that I started making a game using memory blitting instead of
> OpenGL, but I found that on X it runs really slow without OpenGL...
> I was told that it is because you need to give a bitmap to X, that then copy
> it to the vram, even on fullscreen.
> So in my mind the solution would be have direct access to the vram, I found
> out then the existance of XDGA...
> But...
> Does XDGA still exists? It is still shipped with X?
> If the awnser to any of the previous questions are no (or if you want to
> awnser anyway), there are a alternative solution?

DGA is outdated, and usually no longer supported.

The typical way to do that stuff is to upload your contents into
pixmaps, and later blit those pixmaps using XRenderCompositePicture,
this way your bitmaps can even have alpha - very much like OpenGL.
Usually capable drivers will do the whole step on the GPU, if not
you'll end up in pixman's SSE2 optimized blitting routines.

If you need direct access to your contents using the CPU (for effects
or whatever), for large bitmaps it usually pays off to use the SHM
extension, have a loot at ShmPutImage (or whatever its called).
But I really recommend uploading your contents once, and later create
effects and whatever by simply using your pre-uplaoded pixmaps.

Good luck, Clemens

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