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AA+HDR

F

freddiepm61

Gawd
Joined
Oct 19, 2004
Messages
836
Can AA ever work with HDR?
i know rhat it does not in farcry, but does it in splinter cell?
if not why not?
thanks
f
 
On the 6XXX series, I believe it's a hardware limitation of how the floating point buffers work. I don't know if that was changed in the g70 core, or if it's simply a logical impossibility to do both to the same scene.
 
It is a hardware limitation right now, the NV40 and G70 do not support MSAA with the FP16 framebuffer. SSAA however does work, but as you might imagine it takes a huge performance hit.
 
Isn't it just FarCry's OpenEXR style that can't be ran with AA? I'm pretty sure there are different methods of HDR, just like there are different methods of antialiasing.
 
robberbaron said:
Isn't it just FarCry's OpenEXR style that can't be ran with AA? I'm pretty sure there are different methods of HDR, just like there are different methods of antialiasing.
Click to expand...

Yes there are different methods of HDR, the method used in FarCry and SC:CT uses the FP16 framebuffer on the NV40 and G70 for high precision HDR rendering and the NV40 and G70 do not support MSAA with the FP16 framebuffer.

There is another method of HDR using Pixel Shaders, but of course it's precision is lower, but AA does work with it since it's just a pixel shader.

The only two games I'm aware of right now that are coming out soon to support the lower precision Pixel Shader HDR is the Lost Coast map in Half Life 2 and the new game Serious Sam 2. Half Life 2 lost coast will support both pixel shader HDR and FP16 HDR.
 
Brent_Justice said:
There is another method of HDR using Pixel Shaders, but of course it's precision is lower, but AA does work with it since it's just a pixel shader.
Click to expand...

Is that the way ATi was originally doing it on the radeon 9700 (example: their dynamic range demo download from their site)
 
illgiveumorality said:
Is that the way ATi was originally doing it on the radeon 9700 (example: their dynamic range demo download from their site)
Click to expand...

yes, none of their current cards support FP16 in the framebuffer
 
Skrying said:
Any clue on which method takes the larger performance hit?
Click to expand...

depends on the use and the hardware

with PS HDR a game dev could go all out putting it everywhere, in which case you'd want a video card that is fast at pixel shaders

with FP16 HDR you'd want a vid card that's fast at that

FP16 is more precise and correct, hey, it's what ILM uses, the NV40 was the first gen cards to support it, the G70 is the second gen supporting it and NVIDIA has improved the performance of FP16 HDR, as is seen in SC:CT, I am now able to play it at 16x12 with HDR and Soft Shadows with very high framerates with a single 7800 GTX
 
IMO, the FP16 method simply isn't worth it, too big of a performance hit plus no FSAA. If forced to choose, I would take FSAA any day.
 
I forsee months of arguing about whose HDR is "better". Looks like Nvidia did it "right" and ATi is going to do it "fast". FP24 vs FP32 anyone?
 
trinibwoy said:
I forsee months of arguing about whose HDR is "better". Looks like Nvidia did it "right" and ATi is going to do it "fast". FP24 vs FP32 anyone?
Click to expand...

well we don't really know for sure what the R520 will support yet
 
Brent_Justice said:
yes, none of their current cards support FP16 in the framebuffer
Click to expand...

Does that mean i could use HDR with my 5900xt? :)
 
Sly said:
Does that mean i could use HDR with my 5900xt? :)
Click to expand...

HDR done through pixel shaders yes

HDR through FP16 framebuffer no

the NV40 was the first generation to support that as I noted previously
 
Brent_Justice said:
HDR done through pixel shaders yes

HDR through FP16 framebuffer no

the NV40 was the first generation to support that as I noted previously
Click to expand...

Just making sure. The one discussed here were the ATI cards :p I pretty much gave up on ever seeing HDR. I wonder if i can activate PS HDR in farcry, never actually tried it :)
 
Sly said:
Just making sure. The one discussed here were the ATI cards :p I pretty much gave up on ever seeing HDR. I wonder if i can activate PS HDR in farcry, never actually tried it :)
Click to expand...

Farcry doesnt have PS HDR I believe. Its FP16 only I think.
 
so with my dual ultras, i will basically have to always choose between hdr and aa?
also, is this transparency aa with the 7800gtx driver based or the card, i.e. can i do it on my ultras?
f
 
freddiepm61 said:
so with my dual ultras, i will basically have to always choose between hdr and aa?
Click to expand...

If the game is using FP16 HDR yes, either HDR or AA, not both at the same time.

If PS HDR then both at the same time is possible.

also, is this transparency aa with the 7800gtx driver based or the card, i.e. can i do it on my ultras?
f
Click to expand...

no, it's a hardware thing, only available on the G70
 
I often wonder how useful HDR really is... Standard 24-bit color images are capable of a dynamic range of around 300:1. Many LCDs these days have a contrast ratio of 500:1 or higher. I'm not sure what the contrast ratio average is for CRTs. It's obvious though that 24-bit color doesn't take advantage of the full dynamic range of at least an LCD screen, but I wonder how much it really matters. Our eyes view a dynamic range of 50,000:1 daily in most cases. I suppose taking full advantage of the dynamic range available to your monitor is a good step forward, but not something worth sacrficing AA for...
 
ok... as it is my thread, i will have a topic change(ish)
as on the whole (at the moment) we have to choose between aa and hdr, which would people choose when playing a game?
Me, I choose aa, as it does massively improve picture quality, and gameplay as when something is very jaggedy on a sniper shot, it is harder to fix. moreover, on the eye candy front jaggedies look far worse than the lack of hdr...
also, for me hdr sometimes detracts from gameplay, e.g. in far cry, when you are in a tunnel you just cannot see outside, which is a pisser if there is someone out there...
so me, I choose AA!
f
 
When you see it in games you'll think otherwise. Did you watch any of those game demo videos from E3? Most of them employed HDR, the games looked incredible.

HDR is the future of gaming.
 
Brent_Justice said:
When you see it in games you'll think otherwise. Did you watch any of those game demo videos from E3? Most of them employed HDR, the games looked incredible.
Click to expand...

I've seen it and I like having my AA more. A lot of the times HDR makes things look to unreal for me to like it, this is the case with SP:CT anyway, I like Farcry's more, but Farcry on the whole to me looks like it was made out of claymodels....... yuck.

I agree with the claim that HDR is the future of gaming, but I believe it will be once HDR + AA is possible, which is the case of the Xbox 360.
 
i agree... games do just look so shitty when they are covered in jaggies, and it is also the point of having a silly sli system like mine....
f
 
Keep in mind Super Sampling AA does work with the FP16 HDR. So you can always play around with those modes.
 
Arkalius said:
I often wonder how useful HDR really is... Standard 24-bit color images are capable of a dynamic range of around 300:1. Many LCDs these days have a contrast ratio of 500:1 or higher. I'm not sure what the contrast ratio average is for CRTs. It's obvious though that 24-bit color doesn't take advantage of the full dynamic range of at least an LCD screen, but I wonder how much it really matters. Our eyes view a dynamic range of 50,000:1 daily in most cases. I suppose taking full advantage of the dynamic range available to your monitor is a good step forward, but not something worth sacrficing AA for...
Click to expand...

The problem is not in representing the image. After all, these screenshots of HDR work in your standard 24-bit desktop, right?
In fact, none of the HDR-supporting cards can actually display more than 24 bit to a monitor. The FP16 format is strictly used as an internal format. It's just necessary as input for the post-processing that does the actual HDR effects, like bloom and exposure. Afterwards, it's quantized down to a regular 24-bit image and displayed. So technically the image you see doesn't have a higher dynamic range than a 'regular' image.
The problem is that without FP16, you cannot generate these images in realtime. You can display them though.
 
I've played Far Cry with HDR too, and I still choose AA over FP16 anyday. HDR is nice, but I will only take it without losing AA or a massive performance hit.
 
freddiepm61 said:
so with my dual ultras, i will basically have to always choose between hdr and aa?
also, is this transparency aa with the 7800gtx driver based or the card, i.e. can i do it on my ultras?
f
Click to expand...

Transparency AA, doesn't do supersampling on the entire screen, it is actually only doing supersampling on alpha textures. People have reported getting much bigger performance hits on games with more alpha textures. So the question also has to be asked does the hyprid supersampling (aka. transparent AA) work with FP16 blending?
 
MSAA TR screenshots I've seen look to be basically doing nothing at all. I'm still not sure if its all its cracked up to be yet. It'd be cool if G70 could handle SSAA TR with HDR, that'd be beautiful, to bad that's a slideshow right now.
 
even if you can do ssaa with hdr, it would merely be a very beatiful and very alluring slide show. even with dual g70 and fx-55...
f
 
Brent_Justice said:
and you know this how?

FP16 HDR is faster on the G70
Click to expand...

Well there's no way to know it since Farcry wasnt included with your preview ;)

But anyway, even judging by the new scores the 7800GTX gets in SP:CT, once you include SSAA's already fairly large hit, HDRs, and then a high resolution things start adding up for a not so great FPS. It could possibly be done at 1024x768 for a playable FPS, but I dont see anything higher than that being to gamer friendly.
 
OK...
with if we take the benchmarks shown from the g70, the difference between 4xaa and the saaa stuff, it is about quartered. add to that the effect of hdr '7' and we can see that it would be a slideshow... maybe at 1024x768, but i think that the majority of people here either have a 1600x1200 crt or a 1280x1024 lcd (which would look crap at 1024x768 as it is not native resolution) and chunky pc owners who have all this stuff want 1600x1200, so...
f
 
Here with 1gb ram, an athlong 64 3800+ and two 7800gtx in sli.... can you think of adding in hdr into this????
see the drop from 4aa to 8aa, when the super sampling kicks in....
f
 
freddiepm61 said:
OK...
with if we take the benchmarks shown from the g70, the difference between 4xaa and the saaa stuff, it is about quartered. add to that the effect of hdr '7' and we can see that it would be a slideshow... maybe at 1024x768, but i think that the majority of people here either have a 1600x1200 crt or a 1280x1024 lcd (which would look crap at 1024x768 as it is not native resolution) and chunky pc owners who have all this stuff want 1600x1200, so...
f
Click to expand...

1600x1200 is nice, but 1680x1050 is where it's at :cool:

I think SLI would address that issue. If you're THAT picky, then lay down the cash to fix the issue!

edit: 2xSSAA and HDR would be playable I think. maybe 8xAF....
 
freddiepm61 said:
would you prefer aa or hdr?
Click to expand...

Depends on the game. High paced games.... I'd prefer HDR. Slower stealth games, probably AA since jaggies are really distracting to me in slower paced games. HDR if the enhanced lighting allowed for more strategic planning and things of that nature.
 
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