WebXR FrameRate

[Maksims]

The developer will be able to control the target frame rate of an XR session based on a provided list of supported frame rates.

XR device can change framerate based on its underlying mechanics, but the user has control over it also. For example, Quest 3 provides these supported frame rates: [ 72, 80, 90, 120 ], and by default it will use 90 Hz. But you can ask it to render with 120 Hz if your app can manage such performance.

New APIs:

// pc.XrManager
xr.frameRate // (number|null) a target frame rate of the current session, or null if not supported or no XR session is available
xr.supportedFrameRates // (number[]|null) list of supported frame rates, or null if not supported or no XR session is available
xr.updateTargetFrameRate(frameRate: number, (err) => { }); // async method to update frame rate based on list of supported values
xr.on('frameratechange', (frameRate: number) => { }); // event when framerate has been changed 

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