WebGPURenderer: Add XRManager.

[Mugen87]

Related issue: #28968

Description

A first version of XRManager with basic WebXR support.

Features like layers, WEBGL_multisampled_render_to_texture or depth sensing are missing and can be added with subsequent PRs.

Tested with a Quest 2. The demo does not fully work when running the demo on Android as an AR demo, yet. I suspect We must apply some array-camera related changes to get that bit right.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	339.53 79.09	336.25 78.28	-3.27 kB -819 B
WebGPU	493.59 137.22	503.11 139.72	+9.53 kB +2.5 kB
WebGPU Nodes	493.05 137.12	502.58 139.61	+9.53 kB +2.5 kB

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.25 112.11	465.25 112.13	+0 B +20 B
WebGPU	563.97 152.82	576.89 156.36	+12.93 kB +3.54 kB
WebGPU Nodes	519.35 142.4	532.28 145.92	+12.93 kB +3.52 kB

[sunag]

We must apply some array-camera related changes to get that bit right.

Awesome! You already know what the changes would be, I can help if necessary.

[Mugen87]

Not yet, tbh^^. I did a quick test with a Pixel 8a when webgpu_xr_cubes worked on a Quest 2.

[Mugen87]

Test link: https://rawcdn.githack.com/mrdoob/three.js/8bbd48e8f2139f08ffcc1f4be79f9ada120d43c3/examples/webgpu_xr_cubes.html

[Mugen87]

On a Pixel 8a and Chrome I get the following runtime errors:

three.webgpu.js:9851 Uncaught TypeError: Cannot read properties of null (reading 'charAt')
at UniformArrayNode.getPaddedType (three.webgpu.js:9851:27)
at new UniformArrayNode (three.webgpu.js:9786:26)
at uniformArray (three.webgpu.js:10021:58)
at three.webgpu.js:10080:36
at Proxy.call (three.webgpu.js:3081:104)
at Proxy.setupOutput (three.webgpu.js:3121:35)
at Proxy.getOutputNode (three.webgpu.js:3103:33)
at Proxy.setup (three.webgpu.js:3113:15)
at Proxy.build (three.webgpu.js:1628:29)
at Proxy.build (three.webgpu.js:1642:17)

as well as

three.webgpu.js:57290 THREE.WebGLProgram: Shader Error 0 - VALIDATE_STATUS false
Program Info Log: invalid shaders�
0:16: L0001: Interpolation qualifiers can be used only for fragment inputs or vertex outputs, found for 'webgl_fd9dbd8b76f9ae82'�

On a Quest 2, the browser console is free from errors.

[sunag]

One thing I remember that hasn't been added support yet is dynamically changing the length of the cameras array in ArrayCamera.

[Mugen87]

Um, that could be the issue. The count of the array camera's sub cameras seems to vary in the Phone AR case.

[sunag]

Hmm.. I'll add that support then.