Copying RenderTarget doesn't work with the WebGL fallback for the WebGPURenderer

[Kycklingris]

Description

Copying a render target to a render target with copyTextureToTexture doesn't work with the WebGL fallback for WebGPURenderer, instead failing with the error "TypeError: Invalid value used as weak map key".

A quick log from chrome as jsfiddle doesn't exactly provide the best logging functionality

index.html:50 webgpu:
index.html:43 finished correctly
index.html:56 webgl:
index.html:61 TypeError: Invalid value used as weak map key
    at WeakMap.set (<anonymous>)
    at WebGLBackend.get (three.webgpu.js:59994:14)
    at WebGLTextureUtils.copyTextureToTexture (three.webgpu.js:62629:41)
    at WebGLBackend.copyTextureToTexture (three.webgpu.js:65685:21)
    at WebGPURenderer.copyTextureToTexture (three.webgpu.js:56292:16)
    at render (index.html:41:14)
    at async init (index.html:57:5)
(anonymous) @ index.html:61
Promise.catch
(anonymous) @ index.html:60

Reproduction steps

1. Create a WebGPURenderer with forceWebGL set to true
2. Create 2 RenderTargets
3. call copyTextureToTexture between the two RenderTargets

Code

const renderer = new WebGPURenderer({ forceWebGL: true });
await renderer.init();

const src = new RenderTarget(100, 100);
const dst = new RenderTarget(100, 100);

renderer.copyTextureToTexture(src.texture, dst.texture);

Live example

• jsfiddle

Screenshots

No response

Version

r180 (also tried r170 but same issue)

Device

Desktop

Browser

Chrome

OS

Windows

[Mugen87]

That is a known issue. When using fresh render targets for a copy, the render targets are not correctly initialized in the WebGL backend. As a workaround, clear the render target once before their initial use: https://jsfiddle.net/o52j0cag/1/

[Mugen87]

This has already been fixed on dev via #31810.

Live demo with dev builds: https://jsfiddle.net/0msz1pco/

[Kycklingris]

I see, I should have checked in the PRs more closely. Thank you :)