FXAA Test

[_mental_]

I'm working on Fast Approximate Anti-Aliasing (FXAA) as a cheap alternative to multisampling.

Here is the Window build for anyone willing to test it. Here is the source code if someone wants to build it yourself.
Keep in mind that I tested using the recent nVidia hardware on Windows only at the moment.

There are 4 quality modes (in Options -> Display Options -> OpenGL Options -> Preferences menu).
For me they are not so different from each other and I would like to gather some opinions on this.

[Rachael]

It looks nice but it is something I may personally never use.

I went ahead and tested it, though, I went through some Stronghold and some TUTNT. (After all what better way to test GZDoom than works by the man who literally lives and breathes GZDoom himself? )

In Stronghold I got about 300 FPS without FXAA turned on, and it went to about 200 when I set it to 4 (which is the "extreme" quality).

As for how it appears - I don't know I think my monitor is too high of a resolution for me to really notice much difference. I can tell what's going on when I stand still for a moment and look at the view - but when I am busy killing monsters and stuff I forget that it's even on.

We're going to need a new menu for all these new features though - the one we have is getting pretty full fast.

My final verdict: It's something that's nice to have, and it doesn't seem to utterly destroy anything, so "why not".

[Graf Zahl]

Lack of antialiasing is something I normally see very quickly. All those jagged edges can really be annoying. Whether this is better than multisampling has to be seen, though.

[Nash]

I actually like and choose FXAA in new, commercial games whenever I can because it actually doesn't murder my FPS and looks acceptable to me (better than no AA). :D Would definitely love to see FXAA support in GZDoom!

[Rachael]

It's not at all better than multisampling - nor is it meant to be. FXAA takes the image "as is" (jaggies and all) and redraws the wireframes over the edges as a micro blur - as if aliasing had been turned on. The result usually looks very smooth and crisp, but it ultimately suffers the same weaknesses of having no multisampling or supersampling at all - so it won't hide the problems you see when you have 3 or more surfaces close together at a distance.

It should also be noted that it only works on geometric edges. It will not work on textures which may have transparent edges - they'll still show jaggies unless some sort of filter (usually a linear filter) is applied to them.

It's purely a post-processing filter, and it is meant to be much faster than multisampling (it is) and still give some effects of anti-aliasing without - as Nash said - murdering your frame rate.

[Rachael]

Out of respect for _mental_ I split this topic (all the SSAA posts) into here: http://forum.drdteam.org/viewtopic.php?f=22&t=7149

Sorry for derailing your topic, _mental_. This is a worthwhile feature and it deserves its own thread.

[_mental_]

Sure, no problem.

However it looks like the easiest way to get some feedback is to commit a feature and wait for complains
I think the quality option can be kept, at least in the shader code, to have some values to tune in the future.

In any case, FXAA is not replacement for any other anti-aliasing techniques. It's just the cheapest way (in terms of performance) to get rid of jagged lines in most cases. This technique is targeting low-end and memory limited hardware like notebooks while MSAA is for middle to high end desktops.

[Rachael]

I think that's up to Graf but otherwise I don't think there's any issues. Nobody who's tried it out has complained so far.

[dpJudas]

Personally this feature gets a thumbs up from me. It is good on low end hardware and is pretty isolated in the sense that if the FXAA setting is off it doesn't really affect any existing code paths. I would probably keep the menu option as a simple "FXAA On/Off" and then pick one of the two middle settings as the On setting.

[Graf Zahl]

Let's wait until after the release which I plan for the coming weekend. I wouldn't want to add anything just a few days before. A second release will be done anyway in the coming months when the currently under-work SSAO stuff and actual normal processing are in.