On 10/21/2013 11:48 AM, Kenneth Graunke wrote: > On 10/21/2013 08:40 AM, Ian Romanick wrote: >> On 10/17/2013 11:09 PM, Kenneth Graunke wrote: >>> Here's my implementation of ARB_transform_feedback2. I believe it's >>> complete; it passes all of our Piglit tests and a lot of Intel's >>> oglconform tests. >>> >>> This should work out of the box on Ivybridge and Baytrail. It won't >>> work on Haswell at the moment, due to restrictions on register writes >>> (to be solved in a future kernel version). Patch 9 will need to be >>> replaced with something that detects whether or not we can write >>> registers from userspace batchbuffers. >>> >>> In the meantime, I figured I'd send out the rest for review. >>> >>> Porting this back to Sandybridge is probably doable, but annoying. >>> Sandybridge doesn't have the MI_LOAD_REGISTER_MEM command, so we'd have >>> to map the buffers and use MI_LOAD_REGISTER_IMM. Seems pretty gross. >>> Plus, transform feedback is done very differently pre-Ivybridge. I'm >>> not sure it's worth it, seeing as it's a GL 4.0 feature. >> >> I assume this is just to support glDrawTransformFeedback? > > No, it's to support glResumeTransformFeedback.
This is also part of OpenGL ES 3.0, so we need to fix it. :( > glDrawTransformFeedback actually just reads pipeline statistics counters > and leaves them free-running. > >> Can you add that information to http://dri.freedesktop.org/wiki/I965Todo/ ? > > Actually, I'm probably wrong...on Gen7 we use MI_LOAD_REGISTER_MEM to > copy offsets into the SO_WRITE_OFFSET(n) registers. But on Sandybridge, > XFB is done using the geometry shader, so it works entirely differently. > I don't think there is a register to load. > > I'll just let whoever looks into it figure it out. Not much insight anyway. > > --Ken _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
