Anti-Aliasing does not reduce aliasing / shimmer as effectively as in Ironwail

[AtifArshad1995]

Recently, I was comparing the AA between Ironwail and vkQuake and I noticed that vkQuake's AA looks much less effective at removing aliasing and shimmering. This is especially notable when using Full AA / FSAA in both sourceports.

Like, even 2x AA in Ironwail seems to be much more effective than 8x AA on vkQuake. I was wondering if it has something to do with my GPU or is it just how the AA works in vkQuake. If it is latter, it would be much better to have AA like that of Ironwail.

As for my hardware.
Laptop: Dell Inspiron 5570
Dedicated GPU: AMD Radeon 530 (Polaris generation)
Intergrated GPU: Intel UHD 620
CPU: Intel i5 8250U
RAM: 8 GB

[bananakid]

I'm not sure what's going on here. It looks like vkQuake's 2× multisampling antialiasing is inferior to Ironwail's 2× multisampling antialiasing ('Edges Only'), but vkQuakes 2× supersampling antialiasing is at least as good as Ironwail's 2× multisampling antialiasing.

↑ Ironwail 0.8.1 No Antialiasing

↑ Ironwail 0.8.1 Antialiasing 2× 'Full' (Supersampling)

↑ Ironwail 0.8.1 Antiasliasing 2× 'Edges Only' (Multisampling)

↑ vkQuake 1.33.1 Antialiasing 2× Multisampling

↑ vkQuake 1.33.1 Antialiasing 2× Supersampling

[Novum]

Only idea i have is that it's probably something about gamma aware sample averaging. That's a setting in the NVIDIA driver that likely only applies to OpenGL these days. But honestly I have a really hard time seeing the difference on my display.

Also you posted the same image twice for Ironwail, so that doesn't help either.

[bananakid]

I've re-uploaded the screenshots for Ironwail, however in both cases (my first and second uploads) it's hardly any difference between 'Edges Only' and 'Full' AA in Ironwail.

Nevertheless I believe the difference in 2× Multisampling is quite pronounced as Ironwail's implementation looks like Supersampling in vkQuake. Please examine these screenshots specifically:

↑ Ironwail 0.8.1 Antiasliasing 2× 'Edges Only' (Multisampling)

↑ vkQuake 1.33.1 Antialiasing 2× Multisampling

P.S. I'm using AMD GPU in Windows.

[Novum]

By definition, MSAA cannot affect texture shimmering, it only antialiases edges. If the setting does reduce shimmering in IW then it is applying supersampling. Either because of a driver override or because there is a bug.

Also what is the bug here? If you want supersampling, select supersampling? It's impossible to make MSAA antialias textures, so there is nothing I could do to change this

[bananakid]

Well, I was unsure if there's any bug at all and made a comparison so you don't have to waste time, that's it. It's good the screenshots were good enough to make a reasonable justice, isn't it? It looks like something's wrong or different with Ironwail (like maybe it defaults to supersampling for low altialiasing strength). I personally use only vkQuake so it's good to know that there's nothing wrong with it.

I also decided to double-check because supersampling is resource intensive. So it's worth double-checking if it's possible to have a similar display output with less GPU usage by using Ironwail's implementation. Your brief explanation made all the points. I didn't compare GPU usage in Ironwail to see if there's any difference between multisampling and supersampling in it's implementation, so I leave it for OP to examine and report.

[AtifArshad1995]

@bananakid There is quite a difference between MSAA and Supersampling when I use Ironwail. Best observed with texture filtering turned off and looking at far away walls/textures while moving forward/backward. In Ironwail, Supersampling reduces shimmer a lot better than MSAA does atleast on my end.

That said, both MSAA and Full AA in Ironwail look much better than the respective AA settings in vkQuake on my PC
As in MSAA in Ironwail > MSAA in vkQuake when it comes to aliasing edges
And Full AA in Ironwail > Full AA in vkQuake when it comes to both aliasing edges and especially reduce shimmering

As for GPU usage, Supersampling is definitely much more intensive than MSAA in both ports.

Like for example, in Ironwail I get better fps with 4x MSAA than with just 2x Full AA. Yet I still prefer the 2x Full AA since it looks better.

[AtifArshad1995]

I'm not sure what's going on here. It looks like vkQuake's 2× multisampling antialiasing is inferior to Ironwail's 2× multisampling antialiasing ('Edges Only'), but vkQuakes 2× supersampling antialiasing is at least as good as Ironwail's 2× multisampling antialiasing.

↑ Ironwail 0.8.1 Antialiasing 2× 'Full' (Supersampling) ↑ Ironwail 0.8.1 Antiasliasing 2× 'Edges Only' (Multisampling)

If you open the 2 images side by side, you will notice that there is still a difference. The squares/pixels on the ground textures have less aliasing in the Full AA/Supersampling image

[vsonnier]

OK As I understand it, vkQuake correctly supports antialiasing as-best-as can be, and the rest is up to specific driver settings and implementation differences between APIs and vendors. I'm converting into Discussion, because there is no bug here.