PMREMGenerator: instances share context across multiple renderers

Description of the problem

Using PMREMGenerator.fromEquirectangular in multiple simultaneous three.js renderers causes only the last renderer to have a correctly functioning texture (at least for use as an envMap) This happens even when each renderer has its own instance of pmremGenerator and calls dispose after use.

Here’s a fiddle: https://jsfiddle.net/h37k2ztv/10/

I would expect that initializing a different pmremGenerator for each renderer should be sufficient, but I had to work around it by reinstantiating and recompiling the pmremGenerator immediately before each time it is used (uncomment lines 63 and 64 in the fiddle to do this)

Issue #18842 reports this same issue, but perhaps even without multiple renderers. This merge request may have introduced the unexpected behavior.

Three.js version

• Dev
• r115
• …

Browser

• All of them
• Chrome
• Firefox
• Internet Explorer

OS

• All of them
• Windows
• macOS
• Linux
• Android
• iOS

[Mugen87]

AFAICT, when dispose() is properly used, there should be no memory leak.

Should I close this issue now, or does it get closed when the merge request is accepted?

This happens automatically as soon as the PR is merged. Hence, I would leave it open for now.

Thank you for verifying the PR!

[treyenelson]

@Mugen87 I tried out the fiddle with three.js built from your fork and it worked like a charm!

The merge request that I believe introduced this bug (https://github.com/mrdoob/three.js/pull/15330) intended to solve a memory leak, so I briefly attempted to recreate that test, but it’s out-of-date enough that it might not be worth the hassle. It’s a lot more reasonable in any case to fix the problem outlined in this issue, rather than a memory leak that arises from reinstantiating the loaders / generators every time that a texture is updated.

Should I close this issue now, or does it get closed when the merge request is accepted?