On Fri, Apr 11, 2008 at 6:17 AM, Claude Heiland-Allen <claudiusmaximus@goto10.org> wrote:
And in my experience with oldish AGP graphics cards, GPU->CPU image
copying is rather slow.  PCIe may be better, I don't know.

PCIe is not really better.  With GEM we can't use the asynchronous fast paths since the typical method is to read a fully rendered frame.  Someone could look into using FBOs and async read back.
 
I don't know if there is any way to share GPU memory between independent
processes on the same machine, would be cool.
 
You could try to grab screen coordinates other than the active window.  On OSX 10.5 there is supposedly a flag that makes your context 'read only' which allows other apps to scrape the contents into a texture. 

cgc