On Mon, 2006-03-13 at 16:25 -0800, Ian Romanick wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > David Reveman wrote: > > > I thought that a call to SwapBuffers would always make the content of > > the back buffer undefined. So if you want to use CopySubBufferMESA for > > quickly repainting part of the buffer as the in the spec, you would > > never use SwapBuffers. > > The spec says that the back buffer is undefined to give implementations > the freedom to implement either copy or flip. Since an implementation > can do either, and each results in a different state of the back buffer, > you have to call it "undefined". > > In practice this does not mean that you end up with garbage in the back > buffer. It means that without some additional information, like what > GLX_OML_swap_method provides, you just don't know.
I'm aware of this. glXSwapBuffers (no GLX_OML_swap_method) glXCopySubBufferMESA (dpy, draw, 0, 0, w, h); gives you undefined results. Is it useful to have, glXSwapBuffers (GLX_SWAP_METHOD_OML set to GLX_SWAP_COPY_OML) glXCopySubBufferMESA (dpy, draw, 0, 0, w, h); not give undefined results? For what we like to use this extension for in compositing managers it doesn't matter. > > > By saying that I want CopySubBufferMESA separated from buffer swapping, > > I ment that I want the relationship between CopySubBufferMESA and the > > implementation of SwapBuffers to be the same as the relationship between > > CopyPixels and SwapBuffers. > > So...after going back and looking at CopySubBufferMESA and CopyPixels, > I'm struggling to see what the difference is. Is it just the > CopySubBufferMESA is a guaranteed fast-path, or is there something more > that I'm missing? Or is the utility that the drawable doesn't need to > be bound to the current context? Yes, not having the drawable bound to the current context is an important part. For indirect rendering I need the extension to be able to sync all screen updates done by the compositing manager to vblank. -David ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
