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brady
07-23-05, 05:56 AM
i posted this in another thread but i wanted to start a entire thread on the issue because im very curious about the whole aa+hdr thing. read and comment if you will.

maybe im missing something here. i remember a thread a few days ago where some NV guru was talking about AA and HDR specific to current and future high end graphic parts. from what i can recall he seemed to indicate the reason why hdr and aa dont mix right now. if anyone remembers the discussion please link to it.

my understanding is that both hdr and fsaa are essentially post processed effects and each one is a final step in the rendering pipeline. you cant have two final steps that are as buffer consuming as aa and hdr and so you have to choose one or the other.

in the case of the ps3 from what we all understand its a modified 7800 which seems to operate very much, if not exactly, as its father part. ie, the rendering process is the same, therefore developers would choose whether a game gets aa or hdr.

with the 360 it seems possible that the hdr could be applied as a final step within the r500 and corrosponding ram and then aa is applied as a final final step with the edram.

im sure you can all tell that im no gfx engineer so go easy on me if ive got this all screwed up.

Seph gPu
07-23-05, 11:15 AM
I thought the reason AA and HDR don't "mix" right now is lack of bandwith? I could be wrong. But I swear it takes ALOT of bandwith to have both going at the same time...HDR in Farcry alone eats up every ounce of bandwith the g6 has.

|MaguS|
07-23-05, 11:17 AM
I thought it was due to the method of HDR that most developers are using...

Morrow
07-23-05, 11:29 AM
I thought the reason AA and HDR don't "mix" right now is lack of bandwith?

It is a combination of a bandwidth limitation and the composition of the final pass. Both problems have to be solved in order to make FP16 blending and traditional FSAA possible on our GPUs...

or simply change how FSAA is rendered like it is demonstrated in the new Luna 7800 GTX demo :)

brady
07-23-05, 02:29 PM
It is a combination of a bandwidth limitation and the composition of the final pass. Both problems have to be solved in order to make FP16 blending and traditional FSAA possible on our GPUs...

or simply change how FSAA is rendered like it is demonstrated in the new Luna 7800 GTX demo :)

so does anyone know if the ps3 will be able to perform both functions at once?

Morrow
07-23-05, 03:43 PM
so does anyone know if the ps3 will be able to perform both functions at once?

This has not yet been officially disclosed but I am postively certain that the PS3 will not be able to do FSAA and FP16 HDR at the same time.

Of course the same tricks which were used for Luna can also be used on the PS3 but no one currently knows what tricks nvidia used and what their weaknesses are.

brady
07-23-05, 04:33 PM
This has not yet been officially disclosed but I am postively certain that the PS3 will not be able to do FSAA and FP16 HDR at the same time.

Of course the same tricks which were used for Luna can also be used on the PS3 but no one currently knows what tricks nvidia used and what their weaknesses are.

hmm interesting. sorry if im being redundant, but that begs the question...will the 360 be able to aa+hdr?

**update** from what i understand, the "trick" that was used in luna was that aa was performed in engine (software). this is exactly what david kirk suggested would be done in "the future". i believe that luna, among other things, is an example to developers of how this is to be accomplished. hdr on chip. aa in software.

SH64
07-23-05, 04:53 PM
Interesting .. that kinda answers my question of how Luna's demo has no jaggies when AA wasnet enabled in CP.
i thought 4xAA was enabled by default within the demo.

Morrow
07-23-05, 09:28 PM
hmm interesting. sorry if im being redundant, but that begs the question...will the 360 be able to aa+hdr?

Yes, the xbox 360 is capable of FSAAing FP16 HDR the old, "traditional" way unlike the PS3 which can't.

**update** from what i understand, the "trick" that was used in luna was that aa was performed in engine (software). this is exactly what david kirk suggested would be done in "the future". i believe that luna, among other things, is an example to developers of how this is to be accomplished. hdr on chip. aa in software.

yes, this is some kind of software trick. What is strange, is that this FSAA does not take the performance hit you would expect from FSAA and at the same time is too good looking to be just some kind of "special edge blurring post filter".

I'm really anxious to find out how nvidia did it...

brady
07-23-05, 09:34 PM
Yes, the xbox 360 is capable of FSAAing FP16 HDR the old, "traditional" way unlike the PS3 which can't.



yes, this is some kind of software trick. What is strange, is that this FSAA does not take the performance hit you would expect from FSAA and at the same time is too good looking to be just some kind of "special edge blurring post filter".

I'm really anxious to find out how nvidia did it...

so, it seems safe to guess that both consoles will be doing aa+hdr. the 360 seems to takes a more brute force approach. the ps3 will more than likely be using nv's new "trick" (aka offloading aa to the cell and having it performed in engine and then having hdr applied at the end of the rendering pipeline).

on another note. it would be very neat if nv could produce aa+hdr on pc's with sli setups. one card could be entirely devoted to either hdr or aa. but from what i have read tonight you would still have a serious bandwidth problem.

Morrow
07-24-05, 06:22 AM
so, it seems safe to guess that both consoles will be doing aa+hdr.

Technically seen the Xbox 360 can render MSAA and FP16 blending HDR at the same time and the PS3 cannot! Make no mistake, the PS3 is NOT capable of that feature!

It has yet to be seen what nvidia exactly did with the Luna demo and whether this can be used in any game or even if it is possible to compare this "new" AA with the "traditional" MSAA like we have been used until now.

No one knows for sure if nvidia's trick will be used in any game and if it really is a MSAA equivalent rendering method

msxyz
07-24-05, 09:16 AM
A simple trick is to use a render target bigger than the final resoultion. Sort of supersampling, but you're not limited by hardware (ie you can do 1.5x or any non integer ratio).