PDA

View Full Version : Lost Coast , difference in IQ?


Peoples-Agent
09-22-05, 01:23 PM
Can anyone here spot the difference in IQ between these two pictures.... just been having a debate with an ATI lover about this.

Lost Coast.... 1600 by 1200, 4x AA, 16X Anistropic.

Here is the 7800GTX piccy.....

http://www.bit-tech.net/content_images/lost_coast_benchmark/eyecandy1.jpg

And here's the ATI X850.....

http://www.bit-tech.net/content_images/lost_coast_benchmark/aticomparison1.jpg


What do you folks make of this?

To me the 7800GTX textures seem alot sharper, almost as if some of the ATI ones have been smeared to an extent.

Not a new topic, but still.... can anyone here notice?
Would like to know what you IQ fiends find.

- D -

Buenamos
09-22-05, 01:28 PM
I think the 7800gtx's pic is just a tad bit darker, making it look as though a few textures look "more appealing to the eye". I can't really tell much difference. But, I know when I switched from my x800xt pe to my 7800gtx's, the anisotropic filtering wasn't quite as nice. BUT that was only when I saw it in motion, just still captures I can't tell. Of course, that's MO, not fact.

|MaguS|
09-22-05, 01:35 PM
I only care that 7800GTX performance is lightyears ahead of any currently released ATI card in Lost Coast! :D

Garp
09-22-05, 02:25 PM
Its hard to make a rational call on it either way. Both pictures are good quality, both have better things about them than the other.

Take that rock sticking out of the water. On the Nvidia, the texture is a little sharper (but also affected by JPEG artifacts.. you should never use a lossy compression for image quality comparison), but if you look at the boats textures on the ATI its better. *shrug*

I'm not fussed about trivial differences between them like that. When it gets down to such small differences as that then the only information that should be interesting anyone is the speed with which it achieves it.

maxbero
09-22-05, 05:02 PM
I think it's bloom not Hdr as the 7800s can not use AA + Hdr

acrh2
09-22-05, 05:48 PM
I think it's bloom not Hdr as the 7800s can not use AA + Hdr

Two questions:
1) why can't 7800 use HDR+AA?
2) what is difference between bloom and HDR?

Peoples-Agent
09-22-05, 05:49 PM
I think it's bloom not Hdr as the 7800s can not use AA + Hdr

But now they can, that's the whole big deal with this Lost Coast thing.

DeaDLocK
09-22-05, 07:15 PM
I think it's bloom not Hdr as the 7800s can not use AA + HdrNope. It is only in Far Cry that this is the case, because they use a method of rendering HDR in which disabling AA is a requirement.

In Lost Coast, a different method is used which allows FSAA and all the other gimmicks.

Noticed how both HDR and AA are enabled in the Luna demo?

adpr 02
09-22-05, 09:05 PM
Nope. It is only in Far Cry that this is the case, because they use a method of rendering HDR in which disabling AA is a requirement.

In Lost Coast, a different method is used which allows FSAA and all the other gimmicks.

Noticed how both HDR and AA are enabled in the Luna demo?

Right, ATI made a form of HDR which has minimal performance impact AND u can use AA with. Far cry was just badly coded as it is one of the first to have HDR and developers werent as skilled.

acrh2
09-22-05, 09:22 PM
Right, ATI made a form of HDR which has minimal performance impact AND u can use AA with. Far cry was just badly coded as it is one of the first to have HDR and developers werent as skilled.

Is this an opinion or fact?

OWA
09-22-05, 09:32 PM
I think it's opinion. I think they're using a compromise method of HDR that can be used on SM2.0 computers by using integers instead of floating point. Supposedly, doing it that way can causing artifacts such as banding but as we've seen, it can also look pretty good. I'm over my head trying to explain this though but maybe some the more knowledgeable guys will chime in soon.

Edit: Also, you can try the utility rthdribl, the one everyone uses to test for heat issues with their cards, to see that HDR can be done on SM2.0 cards.

aZn_plyR
09-22-05, 11:19 PM
Is this an opinion or fact?

does it matter? :P

fivefeet8
09-23-05, 12:24 AM
I think it's bloom not Hdr as the 7800s can not use AA + Hdr

The Lost Coast Level uses integer render targets for it's HDR. Far Cry and Splinter Cell: CT both use FP16 filtering/blending for it's HDR(except when run on ATi hardware in the new SM2 path). Different ways of doing HDR. We won't subjectively know which has better color/lighting reproduction until the level is released.

Humus also recently released a small HDR demo which probably uses a similar technique to the Lost Coast Level. JCD is also busy with his own HDR demo it seems. But his will use FP16 filtering/blending. ;)

http://www.humus.ca/index.php?page=3D&ID=62

http://www.realityflux.com/abba/

ViN86
09-23-05, 12:53 AM
as was said before, both images have strong and weak points. take the gun for example. in the ATI image, the IQ is much better, as the lines and barrel are smoother and look more real. however, the shading with the 7800GTX seems much richer to me.

if he says his x850xt pe is better, just compare frame rates, that will end the discussion :p

GamerGuyX
09-23-05, 01:56 AM
Is this an opinion or fact?

Obviously opinion because he sounds so stupid saying it. I'd like to see him try to code a game like Far Cry.

Mr_LoL
09-23-05, 02:19 AM
Right, ATI made a form of HDR which has minimal performance impact AND u can use AA with. Far cry was just badly coded as it is one of the first to have HDR and developers werent as skilled.

:screwy:

Demigod
09-23-05, 04:45 AM
Right, ATI made a form of HDR which has minimal performance impact AND u can use AA with. Far cry was just badly coded as it is one of the first to have HDR and developers werent as skilled.
Wrong Valve tried 4 different versions of hdr ATI had nothing to do with it. Farcry wasn't badly coded either. Adding hdr globally to the game isnt easy. Also their hdr is using a 3rd party system which they had to integrate into their systems, not an easy thing to do without breaking the game. It was also never officaly supported, it was just released for people to play with.

Farcrys hdr is also higher precision (16bit floating point with blends + filters though valve haven't said what precision they use here. For ati cards (current) it cant be higher than 8 bit float or 16 bit int as that is all they can do with no blend or filters.

So VALVEs method has the advantage of AA but it will be lower precision at least on current ati hardware. As the iq isnt that different between the ati/nvidia shots I think they are running at a lower precision on all hardware.

john19055
09-23-05, 08:24 AM
If you want to get very picky you can tell small differences between the two ,as one looks better at some things and the other looks better at other things but when they are that dam close it does'nt manner they both look good and the 7800GTX is a lot better better card IMO.

smallSHEEP
09-23-05, 01:58 PM
To me the 7800GTX textures seem alot sharper, almost as if some of the ATI ones have been smeared to an extent.


If by that you mean that the quality of ATI AA is better than nVidias implementation then yes. :)

superklye
09-23-05, 02:29 PM
I honestly think they look exactly the same.

Ninjaman09
09-23-05, 02:37 PM
If by that you mean that the quality of ATI AA is better than nVidias implementation then yes. :)
AA doesn't have an effect on textures. :)

xquizette
09-23-05, 05:59 PM
I honestly think they look exactly the same.

same.

acrh2
09-23-05, 06:22 PM
AA doesn't have an effect on textures. :)

You probably meant to say "it shouldn't". AA used to blur the textures to a very large degree in the past. I believe it still noticably does that, but to a much smaller extent.

NoWayDude
09-23-05, 07:09 PM
http://arstechnica.com/articles/culture/lostcoast.ars/3

A good explanation fot HL2 HDR + AA method


On NVIDIA cards, it stores these values as 16-bit floating point data (what is known as a "linear color space," as opposed to separate RGB values), and on ATI cards stores it as a 4.12 integer value (again a linear space). The advantages of this technique are many. All DirectX9 hardware is supported, and because it does not require that much extra texture memory the performance hit is small even on an ATI 9600. Fog effects work, and so does FSAA. The only real downside is that HDR effects are not supported with refraction, so while light will still stream in nicely through stained-glass windows, you won't see the HDR effects when looking directly through the window at the sun. It is a small price to pay, however. This technique will be shipping with the Lost Coast, and the upcoming Day of Defeat: Source (the latter of which is already partially available for preloading via Steam, awaiting only the final code)

(Bold part my edit)

what's a 4.12 integer value?


fixed precision, 4 bits for the integer part, 12 bits for the fractional part.

For reference, formats that have 8 bits per component are read as fixed precision from 0 to 1 in the pixel shader (8 bits for the fractional part).

http://www.beyond3d.com/forum/showthread.php?t=23504