Nvidia's TXAA for Kepler

Your texture compression analogy is flawed because it only considers this issue from one angle, which is quality. As in this scenario different techniques have different tradeoffs in terms of performance and memory consumption, so the situation isn't really as simple as you make it out to be.

Not that I want to be too defensive of some Nvidia marketing piece...I'm just looking at this for the point of view of a developer who might consider using TXAA (or a technique very similar to it), and is already well aware of the problems associated with MSAA and tone mapping.

 

Why tone-mapping after resolve is wrong



From this thread:

http://forum.beyond3d.com/showthread.php?t=22472

What's depressing is that that thread is 7 years old and developers are still mostly fucking clueless on this subject.

 

I disagree. What we're talking about here is simply optics and sampling. There's never any situation where a image is taken without a lens. All that's been happening with game sampling is that games have been modelling a bad camera system - it wasn't done intentionally but it can be done better if people can get over it. Whether that camera is used for interactive or scripted production doesn't have much to do with the basic sampling theory.

I agree on this part. The game doesn't know where the person is looking so simulating depth of field is a stylistic choice.

All of these are just hacked approaches to the same problem. TXAA will add some blur to an already blurry texture and should be used with a higher LOD bias. But trying to get all of the assets at all of the distances to match up with the frequency they should be in screen space by selecting the right assets at the right place is like balancing on a pin. There are probably better ways to do it and doing the sampling correctly in the AA resolve is a good one. It's what's done in CG movie production for this reason.

There may not have been any supersampling happening on the transparent surface. Not really TXAA's fault.

 

I agree with Timothy that a larger resolve filter is worth doing. If you want more sharpness beyond that, render at a higher base resolution. The box filters we've been using for resolves really are totally trash and there's no reason a modern GPU can't do better.

LOD bias wouldn't totally solve the issue and you could reintroduce aliasing/noise. The issue is that compared to layering it on top of super-sampling, a wider resolve filter is not actually sampling the texture function at a higher rate (like you would by rendering at a higher resolution). Thus with an LOD bias you could easily skip pixels that can be arbitrarily important to the final frame, especially when considering HDR, bloom, etc. i.e. flicker is back!

Regardless of intentions, he really should have showed both cases (tone map pre/post resolve). If he still wants to make a correctness argument on the latter he can do that by showing cases in which it fails and TXAA looks better, but comparing just to the tone map post-resolve case and then hand-waving an argument about how pre-resolve is wrong is a bit weak IMHO.

I'd still love to see more detailed information about exactly what this is doing and why it can't be implemented on any DX10.1+ card. What's the hardware-specific feature that is being used exactly?

 

Please remember where we came from:
„Does he not also say that he did the basic implementation for TXAA and has no control over what each developer makes of it?“
That's what he's saying in this blog comment I sort-of linked to and that's all that I'm referring to: He's doing the basic implementation and everything else is up to the developer - including, and that is my speculation as I've said based on what the lesser texture detail in the OP imlies, some sort of post-processing, like MLAA or FXAA are. Not more not less - and Tim's statements do not hint at that this is out the question. It is just not part of the basic TXAA design.

 

Please re-read what I've said:
„…As it stands, for me those shots look like there's only an FX/MLAA-like filter and no higher resolution, aka higher quality source material from which the downsampling took place.“ [my bold afterwards]

I don't need any confirmations for catching the loss of detail that you already acknowledged - and as obvious for a gaussian filter I wouldn't really describe it's visual effect thankyouverymuch.

I'd be happy to see further links though, to assess what's really going on there - probably a bit more substantial than a vague hint to Timothy's Blog in general.