| Summary: | GL_ARB_transform_feedback2 on i965 gen6 | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | Felix Potthast <mail> |
| Component: | Drivers/DRI/i965 | Assignee: | Kenneth Graunke <kenneth> |
| Status: | RESOLVED FIXED | QA Contact: | Intel 3D Bugs Mailing List <intel-3d-bugs> |
| Severity: | enhancement | ||
| Priority: | medium | ||
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
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Description
Felix Potthast
2017-02-16 17:54:03 UTC
Looking at this again, we apparently never implemented Pause and ResumeTransformFeedback() driver hooks...which meant that we actually failed to restore the streamout buffer writing location during [Pause A -> Bind B -> ... -> Bind A -> Resume A] situations. Honestly, I think we forgot that this was a part of ES 3.0...there aren't any failing tests for this in the CTS, so it looked like everything was working. There is a failing Piglit test, which I'm guessing came about after we had done ES 3.0 and moved on. I remember looking at implementing GL_ARB_transform_feedback2 back in the day. I saw the lack of MI_LOAD_REGISTER_MEM and figured Pause/Resume would be painful to implement. Of course, I failed to notice that there's a command to do this...but the hard part is that there isn't a register to read, making it hard to obtain the value at Pause time. Of course, this is part of ES 3.0, so we have to do it anyway. I've found a solution that seems to work, and should fix those problems. At that point, GL_ARB_transform_feedback2 only has one feature over and above ES 3.0 - glDrawTransformFeedback(). However...that's easy. The mechanism for the above bug fix makes this just work with no additional code. So I think we can turn it on. I have no idea how well WebGL 2.0 will work... Patches on mesa-dev: https://patchwork.freedesktop.org/series/19825/ Fixed on master by: commit 0a7b252c5b0f5c5c0e114d913d6153bd2cc44ce9 Author: Kenneth Graunke <kenneth@whitecape.org> Date: Thu Feb 16 20:05:39 2017 -0800 i965: Enable ARB_transform_feedback2 on Sandybridge. And covered in news by: http://phoronix.com/scan.php?page=news_item&px=WebGL-2.0-Sandy-Bridge Nice work, Thanks! |
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