MSAA Support Added To The OpenSWR Software Rasterizer

Intel's OpenSWR graphics software rasterizer living within Mesa now has experimental support for MSAA.

Should you be needing multi-sample anti-aliasing with SWR, it will be found in Mesa 17.1. But for Mesa 17.1 there still may be some bugs and work is being done on further improving the performance. While MSAA support in the software rasterizer may not seem like a big use-case, apparently some Intel customers are after it, "We wanted to get the changes out now to allow several customers to begin experimenting with MSAA in a software renderer. So as not to impact current customers, MSAA is turned off by default - previous functionality and performance remain intact. It is easily enabled via environment variables."

If you find yourself using OpenSWR, it can be enabled via SWR_MSAA_FORCE_ENABLE environment variable and SWR_MSAA_MAX_SAMPLE_COUNT for specifying the MSAA sample count up to 16x. Details via this commit.