88b72925d0
Using SSE2 intrinsics when available for this kind of conversions. It's not totally accurate, but accurate enough for the purposes where we're using direct colorspace conversion by-passing OCIO. Partially based on code from Cycles, partially based on other online articles: https://stackoverflow.com/questions/6475373/optimizations-for-pow-with-const-non-integer-exponent Makes projection painting on hi-res float textures smoother. This commit also enables global SSE2 in Blender. It shouldn't bring any regressions in supported hardware (we require SSE2 since 2.64 now), but should keep an eye on because compilers might have some bugs with that (unlikely, but possible).