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Old 02-27-03, 10:54 AM   #29
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Join Date: Jan 2003
Location: Austin, Texas
Posts: 9,297

Originally posted by Chalnoth
Well, I can pretty much guarantee you that JC is not going to be using an integer format (framebuffer aside). The benefits of moving to floating-point are just too great. Not only that, but he's been going ga-ga over the possibility of using floating-point...

As an aside, I do think it's kind of funny that so many people seem to be ready to consider FP16 absolutely inferior to FP24. In particular, remember all of the 16-bit vs. 32-bit arguments of the past, back with the Voodoo3 vs. TNT2 Ultra?

Now, as then, there are always going to be differences, but I still feel that 16-bit FP is enough for most any color calculations, but the differences may become apparent for non-color data pretty quickly.

In particular, remember that it's the dark end of the spectrum that needs more accuracy, and 16-bit FP offers higher and higher accuracy (i.e. fewer visible errors) as the image gets darker.

One other thing to keep in mind is that 3DMark03 uses PS 1.4 for most of the shaders in their tests. PS 1.4 doesn't have the accuracy of FP16. So is there a reason to use FP32 in 3DMark03?
no doubt 16 bit IS useful but remember that mathematically.. the first 6 bits are already assigned for other purposes so for all intents and purposes 16bit is really 10 bits... when you look @ it like that you will see there is a lot more headroom with 24bit than 16bit FP... 32bit FP is good... no doubt but I would have to wonder whether in order to get playable framerates with info stored using 32bit FP is going to be feasible?

that being said I do agree that 16bit FP is not as bad as it is made out to be.. but there are distinct advantages as well...

due to modern architecture/core clocks as well as the quality of games... I don't think you can truly compare arguments concerning voodoo and tnt2 cards with todays lineup either
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