https://bugs.freedesktop.org/show_bug.cgi?id=47375
--- Comment #35 from Barto <mister.free...@laposte.net> 2012-07-26 20:33:26 PDT --- (In reply to comment #31) > (In reply to comment #29) > Unfortunately I think this is expected. Previously swrast didn't map whole > buffers, only parts of them. For much simpler and more robust code though > swrast fallbacks now maps the full buffers, an operation which is hideously > expensive at least with radeons (as you've got to blit back the buffers from > the card memory to system memory). I believe blender draws some little things > on a large buffer, so the performance of the swrast fallback is fully > dominated > by copying the buffers around, the actual cost of the drawing operation in the > swrast fallback is completely irrelevant. This is also why it's much faster to > just use swrast to begin with as then you don't need to copy the buffers > around > (you should see this if you some some profiling tool like sysprof, oprofile, > perf). > I'm not sure how this could be solved really, I think the best option would be > to modify blender so it doesn't rely on these legacy features leading to > fallbacks. Or similarly try to accelerate these in metaops so it doesn't need > to fallback. > A third option would be to try to figure out the area accessed and only map > those parts (to swrast it would still look like the whole buffer would be > mapped to keep things simple, but the driver would only blit the needed > parts). > The infrastructure for that isn't there and I'm not sure it's desired in any > case, and it would probably only work for the draw buffers and not for > textures > neither. very interesting, thanks, I'm not sure to understand all the facts ( I'm a newbie in opengl/multimedia programming ), maybe, as you said the best solution would be to modify Blender, but there is one thing I don't understand: why blender is very fast if I use the software mode for opengl with 8.0.4 mesa lib ( by using the command "export LIBGL_ALWAYS_SOFTWARE=1" before running blender ) ? is it because only the CPU power works here for opengl instructions and not the graphic card ? ( in this case swrast works differently ? ) it's weird to see the graphic performances decreasing when I use the normal mode ( graphic card acceleration ) with Blender and see the exact opposite when I use the software mode for opengl operations in mesa 8.0.4 -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
