Is SceneOptimizer compatible with XR?

Questions
1

I’m trying to use SceneOptimizer in WebXR Immersive Mode, but not having success. Are they intended to be compatible?

Here’s what I’m observing:

  1. any use of TextureOptimization causes the entire immersive view to go blank - I just see the background color and nothing else from that point on
  2. HardwareScalingOptimization has no effect - I can see it gradually increase the target to 4x via console logs form onNewOptimizationAppliedObservable, but the appearance in XR does not change (and neither does the framerate)

I see both of the above on Quest2 in Oculus browser and in Firefox Reality

2

Adding @RaananW for 1

for 2: this is expected as we do not control the resolution in XR (It is dictated by the device)

3

you don’t control the screen resolution, but you do control the XRWebGLLayer frame buffer resolution, which can be up- or down-scaled for quality or performance adjustments see XRWebGLLayer.getNativeFramebufferScaleFactor() static method - Web APIs | MDN and WebXR Device API

4

I let @RaananW take it from there :wink:

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5

you can change the frame buffer scale factor when requesting the session init. either here:

WebXRDefaultExperienceOptions | Babylon.js Documentation (output canvas options) or if you do it manually then here - WebXRSessionManager | Babylon.js Documentation

The reason the scene optimizer doesn’t work is that XR is using a texture to render the session, and if its size changes XR doesn’t know how to handle it. I assume the scene optimizer tried optimizing the render texture. We will need to mark this texture “non-optimizable”. This way you will still be able to use the scene optimizer while using XR.

want to create a github issue? I will be able to track it better,

6

Thanks, @RaananW - filed.

Re the scale factor, it sound like you’re saying there’s no chance HardwareScalingOptimization will be updated to handle immersive mode. Have y’all ever thought about putting a banner on documentation pages that’s like “This feature is/isn’t available in Immersive Mode” kind of like what MDN does for Web Workers? That could really help us make determinations about implementing features.

2 Likes
7

That’s a good idea. Will require a bit of a change in the documentation, but I do agree that it’s an important information. I’ll add that as an issue in the documentation repository

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