Pico 4 + Overlays = Lag

[Wyverex]

So far I've played using a Valve Index and I'm currently trying out a Pico 4.

I'm using OpenKneeboard which works fine with my Index. 

If I use the Pico 4 without OpenKneeboard (either with StreamingAssistant or VirtualDesktop), everything is smooth.

As soon as I start OpenKneeboard, DCS gets extremely janky. While the frame rate seems to be more or less the same, there's an extreme lag and it looks like both eyes have a different refresh rate. It's basically unplayable. The problem goes away as soon as I close OpenKneeboard. The same happens with any other application that renders overlays into the scene.

Does anyone else have this issue?

[SebastianR]

Yes, with openxr toolkit fps overlay counter. Thats why i'm using ALVR https://github.com/alvr-org/ALVR

[Wyverex]

It seems that using OpenXR is the culprit here. Everything is fine if I start DCS as single threaded, without any arguments. If I --force_OpenXR, I see jankiness with overlays. The same with the multi-threaded version (which always uses OpenXR as far as I know).

With DCS obviously pushing towards both MT & OpenXR, that makes me wonder if overlays will work again in the long term. There's no official OpenXR overlay support (and it's probably not going to come either) and even OpenKneeboard with its custom API layer has the same jankiness, at least on the Pico. 

I'll check out ALVR, thanks!

[Wyverex]

ALVR v20 + ST + --force_OpenXR works indeed. However, I can get the same result by just not using --force_OpenXR in ST and going through Streaming Assistant (or VD).

I'd love to use MT though. Using ALVR v20 + MT gets rid of the extreme jankiness but I also get a massive FPS drop if any overlay is active, so unfortunately this isn't a solution either.

 

Edited April 15, 2023 by Wyverex

[Qcumber]

When I use -"-force_OpenXR" in ST it crashes all the time on loading. With MT it loads but crashes when I try to load a mission. OpenVR through VD and steamVR did run well, but since the update yesterday it is really jittery. I might try ALVR. 

[actually_fred]

On 4/15/2023 at 9:47 AM, Wyverex said:

. There's no official OpenXR overlay support (and it's probably not going to come either) and even OpenKneeboard with its custom API layer has the same jankiness, at least on the Pico. 

While it is more work for overlay developers, the OpenXR API layer approach is much more performant and flexible than the SteamVR Overlay system. It's largely equivalent to the game itself adding a HUD or overlay.

For OpenKneeboard:

- if you're using OpenXR + SteamVR , disable OpenKneeboard's SteamVR support, and mark DCS's exe (both ST and MT) as using OpenXR in OpenKneeboard's settings; auto-detect should not enable OpenKneeboard's OpenXR support when SteamVR is in use, but better to be sure. Sometimes though, SteamVR overlay performance is just abysmally bad with any overlay, even FPSVR; OpenXR does not have that problem.

- if that doesn't help, or you're using some other configuration, https://openkneeboard.com/getting-help.html

Edited May 5, 2023 by actually_fred