WebXRController: add grip update event to WebXRController if enabled

[danrossi]

Related issue: #32350

Description

Adds a grip update event to the WebXRController to individually handle gamepad and input source for each controller. The event can be enabled / disabled easily so it's not being called all the time.

I found trying to handle gamepad inputs externally for each controller connected is clunky and should be handled in an event. I was forced to make a patched XRController to do this.

A gamepad helper can then use this event to handle gamepad inputs and dispatch specific events like in my patched XRController. Perhaps this can be added to the examples also.

https://github.com/danrossi/three-xr-controller/blob/main/src/XRController.js#L79

Usage

const controllerGrip = renderer.xr.getControllerGrip( 0 );
controllerGrip.enableUpdate = true;
controllerGrip.addEventListener('update', (event) => {
    console.log("on grip update ", event);
});

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	350.9 83.23	350.9 83.23	+0 B +0 B
WebGPU	616.03 171	616.03 171	+0 B +0 B
WebGPU Nodes	614.64 170.74	614.64 170.74	+0 B +0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	482.96 118.03	483.11 118.07	+143 B +41 B
WebGPU	686.7 186.56	686.84 186.6	+143 B +41 B
WebGPU Nodes	636.54 173.77	636.68 173.81	+143 B +41 B

[danrossi]

I've added the XRGamePad helper and example to complement the new event.

[danrossi]

I hope that design is acceptable. It seems the other method was an update event into just after this. Obtaining the inputSource from the motioncontroller.

https://github.com/mrdoob/three.js/blob/dev/examples/jsm/webxr/XRControllerModelFactory.js#L95

[danrossi]

I have some other controller features to submit for review including GripPointer util like the HandPointerModel which adds a line and cursor which seems to have to be duplicated everywhere. An intersection util to handle the different pointer models now it uses a common api like the HandPointerModel. A controller manager to handle all the different controllers and events. So it's universal.

It's taking parts of my internal controller work including handling transient-pointer for Apple vision.

I found it clunky to manage externally for both controllers.

[danrossi]

I thought I would add these extra addons with the gamepad feature. A universal controller and intersections manager. The grip cursor and line is added into a pointer model so they can be handled the same way as the hand pointer model.