Remove hand-tracking from VRButton's optionalFeatures

[m-blix]

Description

VRButton (and XRButton) has hand-tracking as part of the session's optional features.

const sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor', 'hand-tracking', 'layers' ] };

https://github.com/mrdoob/three.js/blob/master/examples/jsm/webxr/VRButton.js#L49

With the usage of VRButton in various examples that do not even use the WebXR hand tracking API (e.g. https://threejs.org/examples/webxr_vr_rollercoaster.html) this can trigger multiple successive permission prompts (1st for immersive session, second for hands) on certain platforms (e.g. Safari on visionOS). With the Button's as is this annoyance can't be avoided.

Solution

One option to avoid this is to remove hand-tracking from the optionalFeatures list, and instead provide a way to pass in additional features, similar to XRButton's createButton method.

Or, give access to VRButton.optionalFeatures = [...] for easy modification.

(And modify examples that need hand-tracking accordingly).

Alternatives

Alternatively, this issue can be seen as responsibility of developer to copy and modify VRButton code, adjusting optionalFeatures (or requiredFeatures) to suit their needs.

Additional context

No response

[Mugen87]

One option to avoid this is to remove hand-tracking from the optionalFeatures list, and instead provide a way to pass in additional features, similar to XRButton's createButton method.

I vote for that. We could apply the changes of #27030 to VRButton as well and then update the hand-tracking examples. ARButton.createButton() also has a sessionInit parameter.

[Mugen87]

@m-blix Does #27699 look good to you?

[m-blix]

@Mugen87 Yes #27699 looks good 👍

One other consideration, maybe for later or not at all as optionalFeatures is probably fine, but for examples that really require hand-tracking could have hand-tracking as part of session's requiredFeatures list.

[danrossi]

These sessions don't work in the visionOS simulator. How is it advised to detect for hand tracking support now it's trying to force it ?

[mrdoob]

How is it advised to detect for hand tracking support now it's trying to force it ?

Can you rephrase the question? I don't understand it.

[danrossi]

These demos won't launch XR on VisionOS simulator as it seems there is no hand tracking to check controls and it requires it. I'll check again but it says "XR Not Allowed" So to support every device keep these properties optional is the advised method ? Making them required seems to only work on anything that supports it and there doesn't seem to be a method to detect what it supports. I'll do more digging. I figured out the visionOS video playback work around for others for now. Standard. I've done it before.

[mrdoob]

I'm Vision OS 1.1 beta they have started using transient pointers like the ones in Android WebXR. No need for hand tracking.

[Ledzz]

@mrdoob but these pointers exist only when clicking, so there's no way to make "hover" effects, am I right?

[mrdoob]

That's correct yeah...