support direct use of gpu frames such as from webcodecs by library users

[maddanio]

Description

This introduces a user accessible isGPU flag that avoids pixel storage allocation and forces use of only the TexImage api. Previously this was only conceived for the VideoTexture class of three.js, but it is also desirable for example when using the WebCodecs api and feeding resulting frames to three.js

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	687.15 170.18	687.16 170.2	+10 B +15 B
WebGPU	805.82 216.97	805.85 216.97	+28 B +10 B
WebGPU Nodes	805.33 216.83	805.35 216.84	+28 B +9 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	462.85 111.79	462.84 111.79	-4 B +5 B
WebGPU	535.59 144.55	535.61 144.56	+14 B +6 B
WebGPU Nodes	491.75 134.31	491.76 134.31	+14 B +6 B

[mrdoob]

Do you mind sharing more details of your use case and how you're using this?

[maddanio]

I use the webcodecs api to decode video frames and use those as textures in a three.js scene.

[mrdoob]

Can you share some example code?