WebGPURenderer: Introduce RenderTarget3D and RenderTargetArray

[RenaudRohlinger]

Description
Introduce support for 3D textures and texture arrays in multi-render target (MRT) setups for both WebGPU and WebGL backends.

Unlike WebGLRenderer I used suffix instead of prefix (WebGLArrayRenderTarget -> RenderTargetArray) as a 3DRenderTarget felt wrong.

Made a example while working on it that displays 4 meshes:

• A mesh rendering a 3D texture.
• A mesh rendering a 2D array texture.
• A mesh rendering a 3D FBO texture.
• A mesh rendering a 2D array FBO texture.

Each slice of both RenderTarget is incremented and rendered every 50ms.

This contribution is funded by Utsubo

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	339.4 79.05	339.44 79.06	+33 B +7 B
WebGPU	487.31 135.17	488.69 135.58	+1.39 kB +415 B
WebGPU Nodes	486.77 135.07	488.16 135.47	+1.39 kB +399 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.3 112.11	465.3 112.11	+0 B +0 B
WebGPU	557.47 150.87	558.65 151.23	+1.18 kB +364 B
WebGPU Nodes	513.54 140.64	514.73 141.01	+1.18 kB +366 B

[RenaudRohlinger]

Maybe Render3DTarget and RenderArrayTarget? /cc @mrdoob

[mrdoob]

Maybe Render3DTarget and RenderArrayTarget? /cc @mrdoob

I think using suffix may be the best yeah.

RenderTarget3D
RenderTargetArray
RenderTargetCube // We'll have to rename this one

/cc @elalish

[Mugen87]

It seems this PR has introduced a regression: #30283

Rolling back right before the merge restores the shadows in webgpu_lights_physical.

[RenaudRohlinger]

Oh, probably related to the update I did on RenderContext.

[RenaudRohlinger]

I can check later this week, my bad on this one! The issue is only on the WebGPU Backend so puppeteer didn't catch this one.