Originally posted by: Rollo
So GStanfor is right, and ATIs "HDR" + AA is another hacky workaround like they did getting "HDR" for SC:CT?!?!?
No, no. R5x0 can apply hardware MSAA to FP buffers, which is what ATI means when they say they have HDR+AA (see Far Cry and Serious Sam 2 for FP16+AA). But apparently SC:CT's "HDR" uses FX16 buffers, and AoE3 uses FX10.
SC:CT is a spcl case, in that it offers "HDR" to SM2 cards (I think it's been rumored that ATI wrote the SM2 path). As such, SM2 HDR uses FX16 since the SM2-only X-series don't do FP blending and so can't use FP16 as an HDR format (well, not without a severe performance penalty). Apparently the X1-series--which CAN do FP blending and so CAN use FP16 for HDR (and AA it)--just uses the X-series' path in SC:CT. I'm not sure why it doesn't use FP16, like NV40 and G70. It's possible SC:CT's HDR isn't a generic SM3 path but is NV-specific, or it's possible ATI's performance with or handling of FP16 HDR requires some tweaks (remember Far Cry was patched to let HDR work with R520). In either case, ATI or Ubi will have to pony up $ to add that path. They may just let it be and code the next SC game with R5x0 in mind.
Maybe ATI should change all their ads to "MDR+AA", and I wonder if nVidia cards could do similar tricks if they opted to lower precision as well?
I've heard that FX10 is ATI-exclusive so far (Xenos and R5x0). Dunno if NV can support it. Like I said, it's mainly to reduce bandwidth pressure, and I don't think we've seen IQ differences b/w NV's and ATI's AoE3 HDR modes. We'll have to wait for that before we call FX10 MDR--it really might depend on how the dev uses it. But it's probably a safe label, considering SC:CT's FX16 "HDR" doesn't look as dynamic as its FP16 implementation.
I guess nts needs to delete that line about "partial precision" in his signature, or else he's mocking his own card.
Not because of this, no. He's talking about partial-precision calculations ("fixed" hardware precision), and we're talking about the precision of various buffers (flexible memory storage formats): two separate things to mock.
