Examples: Remove FPS workaround in webxr_vr_video.

[Mugen87]

Fixed #19880.
Fixed #13379.

Thanks to requestVideoFrameCallback(), the workaround from #13470 should not be necessary anymore.

This might affect the example in Firefox Reality however Chromium based browsers (like Oculus Browser) should already support it. Testing...

https://raw.githack.com/Mugen87/three.js/95d79137f9e281c54ba637359c8e132ca8c011ca/examples/webxr_vr_video.html

[Mugen87]

Um, it seems there is an issue with Oculus Browser (version 10.2.0.6.111....). requestVideoFrameCallback() is in general supported and called when you view the example in non-VR mode. But when presenting, the callback is not executed anymore. Maybe a bug?

[Mugen87]

Just for the record: Firefox Reality does not yet support requestVideoFrameCallback().

[mrdoob]

/ping @cabanier

[Mugen87]

Um, it seems there is an issue with Oculus Browser (version 10.2.0.6.111....). requestVideoFrameCallback() is in general supported and called when you view the example in non-VR mode. But when presenting, the callback is not executed anymore.

Oh, it seems the same is true for Chrome on Android. I've tested with a Pixel 1 and Daydream and the behavior is the same. requestVideoFrameCallback() is not called when presenting.

[mrdoob]

/ping @toji

[cabanier]

I logged a bug on this last week: https://bugs.chromium.org/p/chromium/issues/detail?id=1107578
Hit the star button so the bug gets more traction.

I agree that this feature would be great for WebXR because it allows you to only pick up the video frames that changed.

[Mugen87]

Hit the star button so the bug gets more traction.

Done! 😊

[usefulthink]

Any chance to create a workaround so we can use VideoTexture in webxr-projects? Maybe add a flag forceUpdate or something to the VideoTexture.update() method that is set by the renderer when a xr-session is running?

EDIT: reading https://crbug.com/1107578 this should be fixed in chromium soon, so maybe not worth it..

[cabanier]

https://bugs.chromium.org/p/chromium/issues/detail?id=1107578 was submitted.
Starting in Chrome 87, requestVideoFrameCallback should work as expected.

[Mugen87]

I'll mark the PR as "Ready for Review" when Chrome 87 lands in production and Oculus Browser uses a respective Chromium build.

[Mugen87]

Tested the updated example today on a Quest with latest Oculus Browser (based on Chromium 87.0.4280.66) and it works fine now. Changing the PR status to Ready for review 🎉 .

[mrdoob]

Thanks!