View Single Post
Old 10-26-05, 12:57 PM   #63
Mr. Nice
Registered User
Join Date: Jul 2005
Location: UK
Posts: 43
Default Re: Quak4 - Quake 4 tuning tool for NVIDIA G70/NV40/NV30 Series GPU's

Originally Posted by tertsi
WI haven't seen any problems with "FP16" options on the NV4x and G7x but there could be a problems on the NV3x because I didn't test my Q4 tweaks on my 5800u or 5900u.
It's those ubiquitous (in both doom3 and quake4) floor gratings, they look fairly fugly with fp16 on (and that's on my 6800GT, ie NV40). Using short temps though is fine.
Originally Posted by tertsi
"SUB/MUL/MUL" should be most of cases 1-2fps faster in Doom 3 and Quake 4 than "MAD/MUL" though "MAD/MUL" was one cycle faster in my fragment program analysis.
Hmmn? If SUB/MUL/MUL uses one more cycle then MAD/MUL (which seems fairly intuitive), why would it be 1-2fps faster? Especially since one of your other optimizations is to replace a MUL/ADD with a MAD? (Although I do see why it was left as MUL/ADD, it looks neater due to the ADD being the summation of the results of two lots of SUB/DP3/RSQ/MUL's).

Originally Posted by tertsi
EDIT! Quake 4 standard interaction.vfp is optimized for ATI Vec3D + Vec1D hardware....
Heh, well structurally the only noticable difference from doom3's is using the specular maths instead of a lookup, and all those masks, so either way I can't see this being an issue for Nvidia hardware. I did note that a comment mentioned the use of .w was more optimal for ATI then .x, presumably because ATI's ability to do 3 component vector plus one scalar in the same pass requires that the scalar is in the .w component (Nvidia hardware is more flexible in this regard).
Mr. Nice is offline   Reply With Quote