PS3's Inability to perform HDR + FSAA

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centerofadmiration

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On another forum there is someone who swears by this philosophy that the PS3 will be unable to handle FSAA and HDR lighting in games due to the systems bandwidth. In my mind I think hes absolutely nuts considering cards like the 6600GT are able to accomplish this task, even if the card isn't specifically designed to be able to pull them both off at the same time. It can still do it with good framerates ( in the 6800 and 7800's case ).

So, someone with alot of tech knowledge could tell me exactly why the Ps3 would not be able to accomplish this task? Something that, for next generation PC Cards and Consoles should be pretty easy.

For example, Heavenly Sword PS3 was utilizing HDR lighting, as was MGS4 and many other titles.
 
I heard the same thing as well.. but for Heavenly sword I read that they were using a different implementation of HDR that is easier on the system and gets similar effects, so that they could use FSAA at the same time.
 
The RSX shouldn't be able to Multi-Sample a FP16 rendertarget.
Therefore if you want to use HDR and AA at the same time on PS3 you might have to either implement your HDR rendering using another method than the Floating-Point rendertargets/blending. Or you use the FP16 support and do some SSAA. The first choice seem to be the best one, quality/performance ratio wise.

In any case, most of the people who talk about HDR, don't know and can't tell the difference between HDR, Tone Mapping, or Bloom lighting, so it's not even a debate worth having, if you ask me.
HDR is just one more PR buzzword and press releases bulletpoint people like to discuss without having a clue about what it is and how it's implemented.
 
m1nd_x said:
I heard the same thing as well.. but for Heavenly sword I read that they were using a different implementation of HDR that is easier on the system and gets similar effects, so that they could use FSAA at the same time.
Click to expand...

Yeah, HS uses NAO32 (pure developer awesomeness, in Italian) instead of FP16 for the backbuffer... which consumes less bandwidth and gets MSAA as well (and looks just as good or better, to boot)
 
What does FP16 stand for anyhow. Its 64-bit texture rendering or something like that right? Why couldn't the PS3 handle it? Just curious, it seems far fetched to be believed considering how powerful the console will be.
 
Floating point 16, each of the four components written into the framebuffer (such as red, green, blue, and alpha-transparency) is represented by 16 bits, with a vertain number of them representing an exponent (I don't know how many, though). And there's absolutely nothing stopping the RSX, should it be what NV has stated it to be, to handle FP16 framebuffers. At all. Even in bandwidth, the only argument that can be made is that if you use FP16, you're going to use a certain amount of bandwidth, and if you use a different method such as NAO32 :)wink: ), you'll get extra bandwidth back. And since FP16 doesn't work with AA in G70 or any other NV cards, and possibly (/probably) RSX as well, that's a double win right there, as you can spend some of what you've won back for AA.
 
Yeah the main reasoning behind his claims was the bandwidth of the RSX-Cell. Its rather high to be sure, but it seems he thinks its not high enough lol.

Someone mentioned using Cell for HDR and the RSX for AA. You think thats in the realm of possibility? I believe both IBM and Sony have displayed Cells ability to perform HDR lighting on its own.
 
I don't believe you can really separate them like that. Where you're doing HDR, you're inevitably either doing or not doing AA, but you're not doing it elsewhere (edit: that is to say, you can't have one do HDR and the other AA, but you can do both of them either using RSX's dedicated hardware, or program Cell to do it). Otherwise you're just doubling up the work you're doing for no reason. But there are certain aspects where you can have RSX render the backbuffer, then pass it to Cell to apply tonemapping, post-processing, and so on. I believe Ghost Recon: AW is doing much the same on 360.

But, regarding his argument, it sounds really asinine to me. The Cell-RSX bandwidth shouldn't even be a factor, since GDDR3 will almost certainly be the place where the backbuffer for rendering will exist, so long as RSX is doing it. In which case, the 35GB/s, which is a pretty significant number, doesn't even come into play.
 
Not MSAA, SSAA yes

centerofadmiration said:
On another forum there is someone who swears by this philosophy that the PS3 will be unable to handle FSAA and HDR lighting in games due to the systems bandwidth. In my mind I think hes absolutely nuts considering cards like the 6600GT are able to accomplish this task, even if the card isn't specifically designed to be able to pull them both off at the same time. It can still do it with good framerates ( in the 6800 and 7800's case ).

So, someone with alot of tech knowledge could tell me exactly why the Ps3 would not be able to accomplish this task? Something that, for next generation PC Cards and Consoles should be pretty easy.

For example, Heavenly Sword PS3 was utilizing HDR lighting, as was MGS4 and many other titles.
Click to expand...

Your friend is mistaken because FSAA has more than one type. One type is MSAA another type is SSAA. So if using SSAA not MSAA, FSAA is no problem with HDR. But SSAA is very big performance issue.
 
centerofadmiration said:
On another forum there is someone who swears by this philosophy that the PS3 will be unable to handle FSAA and HDR lighting in games due to the systems bandwidth. In my mind I think hes absolutely nuts considering cards like the 6600GT are able to accomplish this task
Click to expand...
6600GT can't do that, either. In fact, no current NV card can do HDR+AA. It's one or the other, not both.

So, someone with [very little :)] tech knowledge could tell me exactly why the Ps3 would not be able to accomplish this task?
Click to expand...
Just read B3D's 6800U or X1800XT p/reviews. Apparently NV didn't want to spend the transistors in their ROPs to allow for MSAAing FP whatnots (render targets?). (I wonder if their reasoning was the same as ATI's with VTF, too much work for too little benefit?)

Vysez said:
The RSX shouldn't be able to Multi-Sample a FP16 rendertarget.
Click to expand...
Extreme Mod, you're giving me extreme whiplash! So now we're back to RSX being based off of G70, or does this confirm that not even the 90nm G71+ chips will support HDR+AA?
 
Last edited by a moderator:
G70 doesn't support MSAA and FP buffers. It does support SSAA on all buffers (not difficult). HDR in an INT format allows for MSAA on G70.

RSX is an unknown. We don't know if it supports MSAA on FP buffers or not. If it doesn't, SSAA is going to be a severe bandwidth drain. MSAA is still going to eat into BW but as we hear, Heavenly Sword is managing HDR and a 'nice amount of MSAA', at 720p and we don't know what framerate. HDR+AA is doable as it has been done.
 
Shifty Geezer said:
RSX is an unknown. We don't know if it supports MSAA on FP buffers or not. If it doesn't, SSAA is going to be a severe bandwidth drain.
Click to expand...
It'll likely be an even bigger fillrate (pixel shading) drain tho on all but the simplest of shaders, so framebuffer bandwidth use might not actually be all that much of an issue... I know that by forcing supersampling instead of multisampling on my GF6800, framerate in WoW crashes and burns by going from the mid 30s down to roughly 12FPS or even less in more complex scenes. And there's definitely enough bandwidth for my card to handle more than 12 4x supersampled 1280-rez buffers per second (256-bit bus @ 820MHz)...
 
centerofadmiration said:
Someone mentioned using Cell for HDR and the RSX for AA. You think thats in the realm of possibility? I believe both IBM and Sony have displayed Cells ability to perform HDR lighting on its own.
Click to expand...

I think you'll probably see HDR with AA done via pixel shaders solely, as now in Heavenly Sword, versus a software solution across Cell and RSX.
 
As has been said on these pages, PS3 could just internally render at 1080p and output 720p, giving a bit of SSAA, and it would work with HDR. Obviously it will all depend on the RSX's capabilities to render at high resolutions, but seeing how 1080p has 2x the pixels of 720p, it could look ok. Still not as clean as 4xMSAA the X360 is "supposed" to get for free though.

What i'm thinking is, if people got PS2 to do some of the things it's doing (HDR, AA, Fur, whatever else it was never "supposed" to be capable of doing), PS3 and any other console will be just fine.
 
Rendering in 1080p means a lot of 'wasted' fillrate for most of the buyers. Unless the PS3 has fillrate to burn (has it?) do you really think devco's will take that route?

1280x720 = 921600 pixels
1920x1080 = 2073600 pixels

Right? Or am I missing something here?
 
pipo said:
Rendering in 1080p means a lot of 'wasted' fillrate for most of the buyers. Unless the PS3 has fillrate to burn (has it?) do you really think devco's will take that route?

1280x720 = 921600 pixels
1920x1080 = 2073600 pixels

Right? Or am I missing something here?
Click to expand...

No, rendering internally at 1080p and outputting at a lower res would mean SSAA. That's it really. Doesn't mean you need a 1080p display.

Obviously it burns fillrate, that's what the problem is and that's whats been discussed here... :)
 
!eVo!-X Ant UK said:
You Misst the point
Click to expand...

Actually no, you're missing it. We're not discussing how good a game will ultimately look, we all know anything will look gorgeous, but here it's a technical forum (the console forum has been divided into 3 entities afterall for a reason), so we're discussing technicalities. Mostly useless technicalities you'll argue, but that's the point here.
 
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