AltspaceVR (407060)

[mrxz]

Compatibility Report

• Name of the game with compatibility issues: AltspaceVR
• Steam AppID of the game: 407060

System Information

• GPU: RX 6900 XT
• Driver/LLVM version: Mesa 21.2.1 LLVM 12.0.1
• Kernel version: 5.14.5
• Link to full system information report as Gist: https://gist.github.com/mrxz/7919aec7f3a0da3711bd776b20aa4028
• Proton version: Proton Experimental (experimental-6.3-20211118)

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

Proton log: steam-407060.log.gz

Symptoms

When running in SteamVR the view through the right eye is incorrect. The left eye image somehow ends up at both eyes. The following screenshot demonstrates the issue. Note that the slanted edge of the occlusion mesh is visible on the bottom right for both eyes, while one would expect them to face each other in the middle.

Reproduction

(While AltspaceVR requires an account, this problem can be observed before, and at, the in-game sign-in screen, so no account required to reproduce the issue)

1. Install AltspaceVR
2. Run AltspaceVR, make sure to select "Launch AltspaceVR in Steam VR Mode"
3. Put on the HMD and notice the right eye image being incorrect

The issue was not present in older versions of AltspaceVR, but started with the October 20th update (Patch Notes). It seems to be related to them enabling Single-pass instanced rendering. AltspaceVR uses the ValveSoftware/unity-xr-plugin. This does mean that single-pass instanced rendering can be disabled by changing the AltspaceVR/AltspaceVR_Data/StreamingAssets/SteamVR/OpenVRSettings.asset file as follows:

...
  PromptToUpgradePreviewPackages: 1
  SkipPromptForVersion: 
- StereoRenderingMode: 1
+ StereoRenderingMode: 0
  InitializationType: 1
  EditorAppKey: application.generated.unity.altspacevr.exe
...

This tweak does however have a noticeable impact on performance, making it more of a workaround than a solution.

[mrxz]

Found another workaround. For a brief period Eleven Table Tennis exhibited the same issue (it also uses the unity-xr-plugin). That game allows the render resolution to be changed in-game, and when lowering that setting, the issue went away. Later on I tested it with the render resolution setting from within SteamVR and this seems to work as well for both AltspaceVR and Eleven Table Tennis. Not sure why, but from a certain resolution the bug pops up. So as a different workaround than the one mentioned before, you can reduce the resolution in SteamVR and restart Altspace.

Eleven Table Tennis has since disabled single-pass-rendering (patch notes), so it's no longer a bug there.

[mrxz]

Closing as AltspaceVR has since shutdown.