VR: Double Vision and Incorrect Rendering on HMDs with Non-Parallel Displays

[NeroTheLemon]

Just got a reply from Charlemagne in the discord:

"I believe the team is aware of this and working on it, but I'll flag it again just to be safe."

[AndrewUK1990]

@Straatford87 Please can somebody weigh in as to whether this is officially being considered, fixed or if there are no plans to provide support to HMD's with cantered displays. Thankyou.

[bredsfx]

Hi All,

I did some tests today, think I've found the issue here. The first picture has made from my ULMB monitor, while I was turning with the character on 60hz - 60fps. Because I've only seen something like that in VR with reprojection turned on, I had an idea, that the game does some kind reprojection by default. So I made further test, where I tested CPU and GPU load on 30 and 60 fps (this is the second picture). As you can see the CPU usage didn't changed. If you limit the fps to 15 the CPU usage will proportionately go lower.

So I'm pretty sure they limited the update frequency of the movements/physics to 30 in order to save CPU usage, otherwise a NASA-level CPU would be required to run the game, and they did that reprojection trick to make the game looks smoother.

If I'm right the only question is whether they can optimize the game so much that the CPU load is reduced by half (perhaps a third for 90 fps on my 2700x). I wish them good luck!

[AndrewUK1990]

@Straatford87 ...?

[blitze31]

So, any news?

Looks good aside from double vision.  Also, VR text / menus could be 20% larger.

Pimax 8K-X Normal FOV

SteamVR 50% App 100%

PiTool 1.25

Now to see if rudder pedals are supported and what to map on the HOTAS

[ragesaq]

Would be nice to see the up to date openvr methods and binaries used for long term VR support of all device types.

[Straatford87]

Hey pilots,

We're investigating further optimization in a future patch. In the meantime, here are two tips that can help improve your experience:

• Turn off all Motion Smoothing
• Keep in mind you'll need an incredibly powerful system to run VR in a (per eye) high resolution; e.g. 2x 4k.

[Octar_Fox]

Hey glad to see this being looked at. 

Pimax 8KX, i9900k, 2080 Ti.

I was running Motion Smoothing but one of the earlier game patches broke it somehow - now it randomly introduces massive stutter to either sp or mp scenarios and becomes unplayable. The frame rate no longer locks at half rate and goes higher. A restart of the game can fix it and the same scenario works again. Inconsistent, but unplayable when it happens.

So I've turned it off for now, but at native 4k res I get about 50-55FPS with a mix of game settings. I hope the Motion Smoothing bug gets fixed.

Regardless it would be great to be able to turn off the Parallel Projections option to avoid the double vision and get a significant performance boost, thanks.

[fitzyxxx]

Thanks a great deal for looking into this for us and your other efforts! 

"here is a link to the correct method for obtaining the correct view projection that would eliminate this issue: https://github.com/ValveSoftware/openvr/blob/master/headers/openvr.h#L2040 "

The fix listed above would greatly help performance wise, as well as in the other mentioned ways  - like effects and double vision, scaling of the world, 3d perception, future device compatibility - as the parallel projections hack comes with a performance penalty of something like 30% on Pimax headsets and 5-15% on the Index.  As you mention its hard enough to render already without that at such resolutions. That's the difference between the game running or not running in many cases, or if not the fidelity at which it can run.

Most Pimax users will have 2080 TI's upwards, I have a 3090. Most Index and Reverb G1/G2  users are also likely to have beefy systems. But the more folk who can run the game, and at higher fidelity the better.

Love the game btw, think it will long be considered a VR system seller once all this stuff is patched up. Well done.

[NeroTheLemon]

Has 2.0 fixed parallel projections being needed?

Edit: Just tested it with "renderCameraMode" : "raw" applied to the "steamvr" section inside of Steam/config/steamvr.vrsettings on the Index. Still broken. @Straatford87 this would give Index users a 5-15% performance boost and an even bigger boost for Pimax users. The exact info from the OpenVR api is linked above.