I tried building swr instead of llvmpipe on Windows (as opengl32.dll), using Scons. It works for llvmpipe, but I can't find the appropriate Scons options not script files. It looks like building swr is currently only supported on Linux using automake?
Support for this has recently been pushed. I believe you now can do scons swr=1 libgl-gdi to get the relevant libraries. You still have to use GALLIUM_DRIVER=swr in the environment for it to pick swr over llvmpipe.
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