A few thoughts on MSAA

[Hippo]

Whilst testing recently (for VR performance test), I noticed that in the Tblisi TF51D mission that aliasing did not seem to be much of problem with MSAA off, which was quite a (pleasant) surprise.

 

I have only been flying the F-18 and A-10 where aliasing seems to be more of a problem.

 

I have been extremely critical of ED regarding the change to have deferred shading only, which incurred a 50% fps hit (for me). At the time, to my recollection, flying without MSAA was not an option because of appalling aliasing. I have since been flying with 4xMSAA and cockpit shadows off (to get FPS up).

 

Has something changed over the past year? I tried the A10 and F18 yesterday with MSAA off, and whilst aliasing issues remain, they seem to be a lot less distracting than I recall. Also turning shadows on (low), seems to help mitigate the jaggies as well, and I would be able to afford these now because of the increase in fps from turning off MSAA.

 

I wonder if I'm losing it as the last time (many months ago) I tried DCS w/o MSAA, I considered it unusable because of aliasing artifacts.

 

The jaggies are at their worst around straight edges like the MFD buttons and compass housing on A10, especially when the light hits them so they shine. Same for the edges of buildings. How feasible would it be to implement an OPTION to reduce / eliminate this shine and mitigate the aliasing?

 

I suppose I should chuck an older version on my system to confirm, but just can't be bothered at the moment; so came in here to get some opinions instead.

 

However, I'm quite hopeful that DCS w/o MSAA might now be viable.

Edited July 12, 2019 by Hippo

[Vullcan]

I find 2x relieved shimmering which while bearable high up gets real annoying when trying to land on a boat.

[Quadg]

I have been running without MSAA since 2.5 came out and they have definitely done things to address aliasing issues.

 

when 2.5 first came out long lines of telegraph poles etc used to shimmer terribly but now they don't, as an example.

 

it may have come at the cost of crispness of image (slight blurring) but honestly in a CV 1 its better.

 

so no I don't think you are imagining it hippo.

[USA_Recon]

I also require 2x to avoid tons of shimmering, bad lines, etc...

[DeltaMike]

Questions.

1. What are the performance implications of using Msaa with deferred rendering?

2. What about using Msaa along with supersampling?

3. What anti-aliasing strategy do you prefer for rift, and why? What about S? What about headsets with higher pixel density?

[dburne]

I run 2x MSAA with PD set to 1.4 in my Rift S.

Why - because it looks best to me with still reasonable performance.

 

These are very subjective things and best just to experiment and try different settings to determine what is best for you and your performance.

[javelina1]

I run 2x MSAA with a PD of 1.3 for my Rift S. See my sig for my rig specs. Working for me.

[DeltaMike]

Read a thesis (which I can't find right now) suggesting that the combo of MSAA and SSAA (supersampling, or "PD") was best for text legibility, just wondering if a) that's true (see this) and b) if using the two together really accomplishes anything.

 

Rift users love their SSAA, we think it defeats the screen door effect, although reading Carmack's rant I wonder if it's the best solution, especially for a game like DCS. I know nothing about computers but a bit about cognition, and it seems to me that MSAA is helping with edge detection, which is what I think we need. That should be the key for text recognition, or spotting.

 

MSAAx4 looks fantastic but my GPU can't choke it down. (Well it could, but I ain't turning off shadows, they're pretty. For reference, Vega slots in between 1070ti and 1080 in DCS.) Trying to run any MSAA with any supersampling is a non-starter. Between the two -- MSAAx2, or PD 1.2 -- the effect is about the same visually. Maybe MSAA is a tad better for the world, and PD is a tad better for text. Render times are the same. Which I found a little surprising.

 

That's a problem for those of us too cheap to buy a 2080ti, but it could be a problem for anybody if they upgrade to a higher-res HMD.

 

The narrative I heard from Pimax, and for the Rift S, is, yeah you're driving more pixels, but you don't have to supersample as much, and MSAA is sooooo much more efficient, so you should be fine!

 

Well, I dunno about that.

 

My hypothesis is that deferred rendering is the main thing holding VR back right now. (And what makes the Rift S work is the lower refresh rate.) But I would not know.

Edited July 13, 2019 by DeltaMike

[Hippo]

So I finally put on 2.5.0.15356, and (arrrgh!) - it's ME.

 

Testing with the A10, the jaggies appear just as bad. What I had never realised is how much turning on cockpit shadows reduces the problem. Scenery aliasing is still bad but possibly tolerable, it was always the cockpit jaggies that particularly bothered me.

 

MSAAx2 + low shadows is a very good compromise, but then I can't hold 90FPS.

 

MSAAx4 + no shadows + Kegetys mode is what I've been using for months to keep fps up; but this introduces other issues. It's also starting to get to be a bit of chore to get working lately.

 

As an aside, the cockpit colours have markedly improved. I wasn't testing for performance, but as far as I could tell, there was no discernible difference (to latest version).