WebGLRenderer: Add targetScene parameter to compile() methods.

[Mugen87]

Related issue: #19752

Description

This PR implements the feedback from #19752 (comment) and introduces the targetScene parameter, which was part of the original version of #19752.

@toji I've managed to refactor the code such that compileAsync() reuses the implementation from compile() which makes the code more manageable. Do you think your use case will work with this version of compileAsync()?

BTW: Existing usage of compile() should not be affected by this change. targetScene is optional.

[Mugen87]

This is a subtle but important change. We have to use targetScene here since otherwise we miss environment definitions (and then end up with recompilations during the first render).

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
652.3 kB (161.6 kB)	652.2 kB (161.6 kB)	-133 B

🌳 Bundle size after tree-shaking

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

Filesize dev	Filesize PR	Diff
445 kB (107.6 kB)	444.9 kB (107.6 kB)	-133 B

[toji]

This would work for my use case, yes! (And hopefully many others as well!)

I really like the change to have compileAsync() call into the standard compile(). I wasn't sure how much leeway there was to change it when I put up my previous PR, which is why it duplicated the majority of the logic, but this pattern is much cleaner and more maintainable. +💯

[Mugen87]

Thanks for the review! And sorry for deleting targetScene in my first refactoring 😇 . TBH, I did not fully understand its added value but I can see now how it makes the compile() method more versatile!

[toji]

Thank you! I'm glad that we ended up going through this review separately in the end, because I think having this call through to 'compile()' makes the implementation better.