On Mon, Jun 27, 2016 at 6:36 AM, Alejandro Piñeiro <apinhe...@igalia.com> wrote: > > > On 27/06/16 12:33, Alejandro Piñeiro wrote: >> On 27/06/16 03:08, Grazvydas Ignotas wrote: >>> On Sat, Jun 25, 2016 at 4:54 PM, Alejandro Piñeiro <apinhe...@igalia.com> >>> wrote: >>>> In theory they don't overdrawn. The test has a square formed by N >>>> non-overlapping triangles. With just one call to glDrawRangeElements, >>>> this always works. But if we split it in M subsets, so M calls to >>>> glDrawRangeElements with N/M triangles per call, with low resolutions >>>> and a high amount of triangles, some texels start to fail. And not >>>> always the same amount of texels (so as you mentioned, undefined >>>> territory). Although it is a guess, I assume that is cause for artifacts >>>> on the triangle borders when drawing with so low resolution. >>> Perhaps this is somehow related to this bug: >>> https://bugs.freedesktop.org/show_bug.cgi?id=96624 >>> There a texture problem shows up after one of glDrawRangeElements >>> calls with a lot of primitives. >> Not sure if they are related. Note that the issue I mention gets fully >> solved with glTextureBarrier and additionally, it happens on haswell too. >> >> In any case, reading that bug gave me an idea. I have been toying with >> MESA_DEBUG=flush (that until your email I didn't know that exists). >> Looking at the code, it adds the equivalent to a glFlush after each >> drawing call. Using it gets the test (all 48 subtests) passing. So right >> now Im more biased to think that is an issue on glTextureBarrier. > > Another hint towards being an issue on glTextureBarrier implementation: > if instead of using MESA_DEBUG=flush, I replace glTextureBarrier for > glFlush on the original test (so one full flush after all the square, > but not after each drawing call) all the subtests keep passing too.
I flipped ARB_texture_barrier on for i965 based on comments that others made about how the hw worked. I don't think anyone was *too* sure that it was correct, but the tests (at the time) passed, so I don't think anyone gave it much more thought. Commit 71e187430c, ftr. -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
