I added the Sega Luma Fix option, it happened to be an issue only with Sega systems (Genesis, 32x, CD, and Saturn 2D) so enable the luma expansion for those systems independent of game region. I think it was made that way to save on luma transformations.
While trying to fix the white point mapping block for the clipping issues, I found myself refactoring the whole thing. What I did was compare the current mapping implementation to that of reference Bradford chromatic adaption. Now the temperature is much closer to reference, it won’t work as nice for sub D50 so I limited the mapping to 5005k minimum. Since D93 now could be a bit too blue for some I defaulted to D65, but feel free to adjust to D93, D75 or what you feel like, I even recommend using the “I/U Shift” setting for adjusting temperature as stated before for a more analogue feel.
I also found a reference for the PAL gamma type, and as I suspected it also used the SMPTE-C linear part at the low end so I adjusted the gamma recommendation notes for PAL and NTSC-J.
EDIT: I forgot to promote to RC6. But I just ported the current code to glsl and promoted it. This looks fine to me as a final version if all of you agree. I was having yesterday some leisure time with Sonic and it gave me serious nostalgic vibes. I guess a guide should be coming.