Floating Point Color

[KickItTwice]

Reading the article Anand put up for the Radeon 9700, in the section " Eight Pixel Rendering Pipeloines" it goes on about how a number gets rounded off before it goes into the pipeline using present tech. Floating Point method outputs it without rounding off? If this is the case will games that are already out benifit as the original number was there all along but being rounded off. It seems like it could work. Wishful thinking. We got improvement with older games using FSAA. If someone could elaborate on the subject, please do.

 

[CTho9305]

floating points have a larger range of numbers at the same width of an integer. an 8 bit integer can hold numbers from 0 to 255. an 8 bit float could hold from something less than one to something fairly big. The actual numbers depend on how many bits go into the mantissa and the exponent. However, you lose precision.

The radeon gets around this by using more bits - you get good precision AND range. However, generally, if you want the number, say, 17, the best floating point approximation will be 16.999999999999915314 or somethign like that. It is made up for by the ability to store values between two integers - with integers, 17.1 and 17.0 would be the same. In floats, you would get 17.10000000000000000000132213 vs 17.00000012321 (or something like that) which are different and you can still tell which is bigger - so for these purposes it works better.

Games that are already out should benefit - the lighting quality should improve.

I'm tired - i'll recheck my reply tomorrow

 

[KickItTwice]

Thanks for the reply CTho9305, this is great news to me. Some assume that there is no reason to get the Radeon 9700 because games can't take advantage of it's features untill Doom3 comes out or games that take advantage of directX 9. Better lighting = better image quality. 32 bit color really improved the banding you see in fog or smoke over 16 bit, but it's still noticeable. And it's not just fog and smoke. All of the colors on the screen are affected. I'll get one of these cards shortly after they come out. I may just wait a little bit to see what kind of problems people may have with a new product.

 

[CTho9305]

Originally posted by: KickItTwice
Thanks for the reply CTho9305, this is great news to me. Some assume that there is no reason to get the Radeon 9700 because games can't take advantage of it's features untill Doom3 comes out or games that take advantage of directX 9. Better lighting = better image quality. 32 bit color really improved the banding you see in fog or smoke over 16 bit, but it's still noticeable. And it's not just fog and smoke. All of the colors on the screen are affected. I'll get one of these cards shortly after they come out. I may just wait a little bit to see what kind of problems people may have with a new product.

Personally, I want to see a card like that "in person" - the images I saw were darkened on one side making the comparison totally useless. It is entirely possible that the difference won't be noticeable. I think the textures used would contribute a lot.