Unity Oculus Quest game stutters/lags when head is moved from side to side

Question

Firstly, I've built for the Quest and checked the Unity profiler - everything seems good.

The weird thing is, when I move my head from side to side I don't see any framerate drops in the profiler but I see a noticeable stutter/lag in the headset. When my head is still or even just rotating, everything looks great, there's no stutter at all.

This stutter only occurs when I'm close to my UI and moving my head. When my head is static or rotating, it's all good. If I move back from the UI, there's no stutter either.

I don't think that it's an issue with too complex geometry or materials, as surely this would show up as a framerate drop in the profiler. I'm guessing that the camera movement is causing some kind of frame mismatch which (for some weird reason) isn't showing up in the profiler.

Does anybody have any ideas as to what might be causing this?

Answer 1

Well, I found the issue after narrowing the issue down to a specific set of GameObjects. It seems that the issue was being caused by a custom 'Dissolve' shader I was using. After setting the shaders back to 'standard' the problem went away! Weird...

Answer 2

This happens if your game FPS is lower than the device refresh rate.

For example if the headset is displaying 90 frames per second and your game is only able to render 70 frames per second, the headset needs to reuse a rendered frame every few frames.

When the game doesn't provide a rendered frame in time the device will just take the last rendered "image" and adjust it to the changed headset position and rotation. If it's a rotation change only, you will not notice, because the headset can easily just rotate the last image. But if it's also movement, the device can't simulate the difference of movement of close objects versus far objects on the image, so if you are moving an object close to a camera (e.g. your hand), it will stay at the same position for two frames (every few frames), which will make it look like it's stuttering.