16x FSAA - Not quite the normal FSAA

[Zewks]

So Ive been running some tests with FSAA. Not any real math stuff, just more visual stuff.

 

First off, Ive always been told that the forced FSAA from the Nvidia control panel is better (looks better and performs better) than most in game FSAA. I had been using the in game FSAA 16x setting since the start of Homecoming. So what I did was disable in game FSAA and set the FSAA in the nvidia control panel to 16x. As soon as getting into the game I noticed a huge visual difference. Edges were not completely jaggy, but they were NO WHERE near as smooth as the edges when the in game FSAA 16x was enabled. The games FSAA 16x simply looked immediately noticeably better.

 

So I ran some other tests. Setting the games FSAA to 8x, and then doing another test with the Nvidia set to 8x.

 

Here is were it gets odd. For 2x, 4x, and 8x, there is NO visual difference between the games FSAA and Nvidia's. None..

 

So whats the deal with the games FSAA 16x setting? Is it truly FSAA? It is something more than that? TSAA? MSAA? It certainly seems to be using a better form of AA than just the standard fsaa for sure. Perhaps this is why so many people complain about it having such a huge performance difference from 8x. FSAA is EXTREMELY cheap to use as far as performance on modern day GPUs, even at 16x

 

(and whats up with 32x? I didnt think there was such a thing - I dont notice any visual or performance difference with this compared to 16x)

[Abraxus]

Following this, because I'm legitimately curious too.

[nzer]

I did some googling and was unable to find any explanation whatsoever of how FSAA specifically is different than the other varieties of AA that exist, which leads me to believe it's just a blanket term for all AA.

 

That means CoH's FSAA and nVidia's FSAA could work totally differently. Given how large the performance hit is for CoH's, I wouldn't be surprised if it was actually SSAA under the hood (though MSAA is a lot more likely).

43 minutes ago, Zewks said:

FSAA is EXTREMELY cheap to use as far as performance on modern day GPUs, even at 16x

Pretty sure you're thinking of FXAA, which is a screen-space AA that does edge detection and blending on the final rendered frame. Cheap, but not very strong.

Edited February 23, 2020 by nzer

[Bill Z Bubba]

Do you have FXAA enabled in nvidia control panel?

[Zewks]

24 minutes ago, nzer said:

 

Pretty sure you're thinking of FXAA, which is a screen-space AA that does edge detection and blending on the final rendered frame. Cheap, but not very strong.

 No, you are correct. My bad

 

That would explain why the FXAA in the nvidia settings was different than the FSAA in the game lol

 

 

However

 

That still doesnt explain why FSAA 16x vs FSAA 8x are so dramatically different in game.

16x is doing something with transparency or something as well. Look at the semi distant leaves on trees when you swap between 8x and 16x

Edited February 23, 2020 by Zewks

[nzer]

3 minutes ago, Zewks said:

That still doesnt explain why FSAA 16x vs FSAA 8x are so dramatically different in game.

16x is doing something with transparency or something as well. Look at the semi distant leaves on trees when you swap between 8x and 16x

Sure, it's entirely possible it's doing something different after 8x. Without the source code there's no way to know.

[RubyRed]

5 hours ago, Zewks said:

So whats the deal with the games FSAA 16x setting? Is it truly FSAA? It is something more than that? TSAA? MSAA?

Just taking a quick jaunt through the rendering pipeline, it appears that all of the FSAA done in the game is MSAA, regardless of the number of samples. At least that's what it's asking OpenGL to do, what it actually does is entirely up to the hardware driver. The 16x difference could be a quirk of the Nvidia drivers' implementation, but I'm not that experienced on the particulars of different drivers so I couldn't say for certain.