xserver on OpenGL

[Keith Packard]

Around 9 o'clock on Dec 8, Allen Akin wrote:

> Just to elaborate some of these points:  PBuffers have a "format" system
> completely separate from Visuals (so that you can render to undisplayable
> targets, like high-dynamic-range images or depth buffers for shadow maps).
> Making this work usually requires rethinking memory allocation and going
> well beyond what the X server would require on its own.

Yes, just like Render has Picture Formats that are separate from visuals 
(and can include Alpha information not present in visuals).  I expect 
pbuffers require even more information.

I would have thought that the memory allocation problem was already solved 
though; pbuffers look a lot like textures to me.   One thing that kdrive 
does is allow inactive objects to be pushed out of video memory; that permits 
some auto-tuning of the working set in the graphics card and also allows 
for compaction of the space (kicking things out and later reallocating 
them).

Given the large number of pbuffers that the X server is likely to use, I'd 
like to know if we could place them in AGP memory as well.  Not all 
machines have 256 meg video cards...

-keith