Vive Vision Passhthrough performance

[musk]

Hi, we've developed a Unity app for Oculus Quest 3 that uses a mix of AR and VR scenes, and were considering porting it to the Vive Vision.

In the VR scenes, we saw reduced performance compared to Quest 3, but we think we'd be able to optimise them to the point where we'll be happy with performance, without too big of an impact on the visuals.

However, the AR scenes turned out to be a huge issue for us, as enabling passthrough has a surprisingly big impact on performance. For example, some of our AR scenes ran at 55-72 FPS without passthrough on the Vision, but with passthrough enabled the framerate drops to 25-30 FPS (for context, on Quest 3 we have a stable 72 FPS with passthrough enabled).

We already tried multiple approaches to improve performance - tested with both WaveXR and OpenXR plugins, used Foveated Rendering, tried lower quality settings for the passthrough, but even when testing on a very simple scene (about 100K tris and 30 Batches) we couldn't really reach stable 60 FPS, and ideally we'd be targeting more than that. Our target AR scenes (already after some optimisations) are still 2-3x more complex, with 220K-300K tris and 60-90 Batches, so they don't seem feasible at the moment.

Is such a big performance impact expected for just displaying passthrough? Are there any plans to improve it in the near future?