Nvidia: Petition needs your support (LOD adjustment in DX10+)

[boxleitnerb]

As many of you probably know, AMD has implemented automatic LOD bias adjustments for SGSSAA in DX10/11. This adjustment is necessary for more texture detail and sharpness when using SGSSAA. Without it, surfaces appear blurry.

Nvidia currently only supports (manual) LOD adjustment in DX9 and lower. There is a petition going on over at the Nvidia forums for this feature to work under DX10/11 as well. If enough interest is conveyed, there is a good chance we might get it. I kindly ask for your support.

The petition thread can be found here:
http://forums.nvidia.com/index.php?showtopic=226244

P.S.
A manual adjustment would be preferred over an automatic one, because more control is always better. Also screenshot comparisons with/without negative LOD are always welcome (over there at the NV forums) to further our cause.

 

[SirPauly]

I tried the same thing at Rage and receiving silence for the most part, sadly! Having the ability for lod adjustments with SSAA for DirectX 10/11 content is welcomed. And great to see members trying to be constructive for the community.

 

[Anarchist420]

I would rather have no adjustment than an automatic one because I hate aliasing.

 

[BoFox]

As many of you probably know, AMD has implemented automatic LOD bias adjustments for SGSSAA in DX10/11. This adjustment is necessary for more texture detail and sharpness when using SGSSAA. Without it, surfaces appear blurry.

Nvidia currently only supports (manual) LOD adjustment in DX9 and lower. There is a petition going on over at the Nvidia forums for this feature to work under DX10/11 as well. If enough interest is conveyed, there is a good chance we might get it. I kindly ask for your support.

The petition thread can be found here:
http://forums.nvidia.com/index.php?showtopic=226244

P.S.
A manual adjustment would be preferred over an automatic one, because more control is always better. Also screenshot comparisons with/without negative LOD are always welcome (over there at the NV forums) to further our cause.

This part bolded in red above, is probably the reason.. not enough users find it practical to enable SSAA in DX10/11 games just yet, since the video cards are just not powerful enough yet. It's only practical for those stuck at 1680x1050 or lower, but then again, people with powerful GPUs certainly have enough $ for high-rez monitors or even 3x 1080p.

It's a much better idea to just increase the resolution and enable 32x CSAA + TRAA which also does 24 additional color samples on transparent (alpha) textures (which AMD cannot do). This feature was available since the launch of Fermi. The performance hit is much lower, and also more viable even in Skyrim which does it 3x as fast as HD 7970 does with 8x AAA (as [H] showed in its recent review).

Even then, AMD did not even allow SSAA for DX10/11 games at all until just now for the 7xxx series cards. And we still don't know for 100% sure yet if AMD will actually implement quality bug-free support of LOD adjustment for SSAA in DX10/11 games next month.

But still, it's a good thing to ask Nvidia for more. DX10/11 is a much more stringent spec, so they might have to "beg" M$ to allow for it or something? I wish we were still able to tweak some stuff like triple buffering, color gamma curves, refresh rates, resolutions, etc. in DX10/11 games as easily as with DX9.

I'm all for signing the petition myself!

 

[boxleitnerb]

I would rather have no adjustment than an automatic one because I hate aliasing.

We want a manual adjustment. I don't like automatisms neither

@Bofox:
The spec only concerns the driver default setting. At least this is how AMD explained that they got the WHQL seal with the LOD adjustment in place.
CSAA and TrAA cannot combat shader aliasing which is a very prominent problem nowadays. This is why I love SSAA, it smooths everything without prejudice.

 

[Anarchist420]

since the video cards are just not powerful enough yet. It's only practical for those stuck at 1680x1050 or lower, but then again, people with powerful GPUs certainly have enough $ for high-rez monitors or even 3x 1080p.

The video cards will never be powerful enough to do insanely high resolutions and 4x RGSSAA/8x SGSSAA in the latest games while delivering frame rates that are satisfactory to most people. 1680x1050 back buffers are plenty for me, since I care more about anti-aliasing, RGBA precision, and depth buffer precision than resolution.

 

[ArchAngel777]

The video cards will never be powerful enough to do insanely high resolutions and 4x RGSSAA/8x SGSSAA in the latest games while delivering frame rates that are satisfactory to most people. 1680x1050 back buffers are plenty for me, since I care more about anti-aliasing, RGBA precision, and depth buffer precision than resolution.

Ahhhhh, finally someone who shares the same viewpoint.

Agreed,

 

[boxleitnerb]

Update:
The thread has been pinned at the Nvidia forums and gotten Nvidia's attention.

I have made a comparison in Skyrim with 4xSGSSAA with and without LOD adjustment.
2K HD textures and vurts flora overhaul mod was used along with Bethesdas original HD textures. One can clearly see the improved detail with LOD -1.0. Without lod adjustment, many details are blurred away. I have marked several examples in the pictures for your convenience and made a side by side comparison with selected sections as well.

Remember:
Skyrim is DX9, so here it works. In DX10/11 games, when using SGSSAA, you will get the blur and lack of detail shown in the LEFT picture.

left: LOD 0.0
right: LOD -1.0

 

[Magic Carpet]

Even 3dfx had LOD adjustments, in fact, I think they pioneered it. nVIDIA should carry this tradition on.

 

[SirPauly]

Thanks for the update. It looks like the petition is a sticky thread as well and encourage others to sign the petition.

 

[Anarchist420]

Even 3dfx had LOD adjustments, in fact, I think they pioneered it. nVIDIA should carry this tradition on.

That's because they pioneered RGSSAA and SGSSAA (although they only released parts that could do RGSSAA). You may have already known that, however.

IMO, ATi really screwed things up when they went with MSAA only with the 9700 Pro, as of which I'm probably the only person in the world who didn't find it to be legendary. The 9700Pro's 4x RGMS was better than anything the Geforce FX could do in terms of AA, but it also set a bad precedent of performance ahead of IQ.

I also saw no point in having 6x AA. 6 samples can't be rotated grid, and 6 samples isn't enough for a sparse grid so it was kind of pointless.

 

[SirPauly]

Actually, ATI had a PR slide that offered multi-sampling, super-sampling and mentioned even an ideal mixed mode of super-sampling/multi-sampling -- man, almost had it all there with the R-300 generation.

 

[taltamir]

What is LOD adjustment?

 

[boxleitnerb]

The so called Level of Detail BIAS (LOD BIAS) controls at which distance from the viewer the switch to lower resolution mip maps takes place (see here for more details about mip maps). The standard value of the LOD BIAS is 0.0 (zero). If you lower the LOD BIAS below zero, the mip map levels are moved farther away, resulting in seemingly sharper textures (though, if the scene is moving, the textures start to shimmer) and the opposite cause textures to lose details in a shorter distance from the player.

In essence, setting the LOD bias setting to negative values leads to an improved anisotropic filtering effect. With 8xSGSSAA and 16:1 AF you can effectively get 64:1 AF. Some nice examples of that can be found here:
http://www.pcgameshardware.de/aid,8...AF-Zukunft-trifft-Gegenwart/Grafikkarte/Test/

While SGSSAA by itself provides a texture improvement, this becomes much more prominent with a negative lod bias. Usually, a negative lod bias leads to shimmering and a value of 0.0 is recommended - however, as SSAA fights shimmering, lower lod values than usual are possible without the textures "becoming alive" like an ant hill, leading to increased detail.

Now compared to MSAA, you don't lose texture details without lod adjustment. But you gain nothing either, even though you could:
Left is MSAA, then SGSSAA, then SGSSAA with negative lod.



Ignore the aliasing and just look at the textures and their level of detail. MSAA and SGSSAA lod 0.0 look the same - only when the LOD is adjusted (right picture), you get more details.

 

[taltamir]

Thank you for the answer. I am familiar with the concept I just didn't realize that is what LOD stood for.

From what I read in your quote I would say a better "in short" would be "lower LOD = higher res textures". Although a 3 sentence paragraph doesn't really need to be shortened for anyone worth having a discussion with.

What I don't understand is why people associate it with SSAA... having lower quality textures start further out of from the viewpoint would improve quality even with any AA (MSAA, FXAA, etc) or without any AA, also regardless of AF. (speaking of, AF is more important than AA)

 

[boxleitnerb]

Try to lower the lod to maybe -1.5 (usually used with 8xSGSSAA) without SSAA. This will lead to more detail, yes, but at the cost of massive shimmering and texture crawling. Only SSAA effectively smoothes textures so that this shimmering doesn't occur, allowing for these negative values without such side effects in the first place. FXAA and MSAA don't touch textures at all.

 

[Anarchist420]

Actually, ATI had a PR slide that offered multi-sampling, super-sampling and mentioned even an ideal mixed mode of super-sampling/multi-sampling -- man, almost had it all there with the R-300 generation.

I remember they had a crossfire mode that was 2x RGSSAA and 2x RGMSAA. That's a good mode. However, I didn't know those were exposed on a 9700 pro.

 

[SirPauly]

It was never exposed but there was a PR slide from ATI about these modes. There were intentions of a quality mode: Super-sampled. Performance mode: multi-sampling and mentioning ideal mixed modes for the ideal balance of quality and performance.

Wished I would of saved that slide.

 

[boxleitnerb]

Just a small update to keep people interested. Maybe one or two of you still want to post over there

The game is Serious Sam 3 (DX9). You can clearly see what a negative LOD can do in terms of sharpness and texture detail.
As before: left with LOD 0.0, right with -1.5

And here a comparison between an HD7970 and my GTX580 in Stalker Clear Sky DX10.
The game doesn't have very detailed textures but if you switch between the images in the Windows photo viewer you can still see that AMDs SGSSAA produces the sharper textures in DX10+ apps. A good example is the building on the left.

Left: Nvidia, 4xSGSSAA, no LOD adjustment
Right: AMD, 4xSGSSAA, automatic LOD adjustment (approx. -0.8)