Warn when using GPU-based particles on macOS due to low performance

[Calinou]

On macOS, Particles rendering is much slower than CPUParticles due to transform feedback being implemented on the CPU instead of the GPU.

This closes #54052.

[clayjohn]

I like this, but I am unsure if it is enough. Do users have to run the editor on MacOS to export to Apple devices? Or is it possible to make a game entirely on another OS and then just export to Apple devices?

[bruvzg]

Or is it possible to make a game entirely on another OS and then just export to Apple devices?

With exception to signing / notarization, it's possible to export for macOS from any OS.

[akien-mga]

Indentation issue.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.3.

[lekoder]

I think this notice should be displayed when you set up an export. I was not aware of this issue because I don't develop on OSX - so the game gets poor performance on OSX without a warning of a known issue.

[Calinou]

I think this notice should be displayed when you set up an export.

Unfortunately, it's not possible to conditionally display a warning in the export dialog based on the presence of nodes in scenes.

[Zireael07]

Display it unconditionally then?

[lekoder]

Would it be possible to display a warning next to Particle2D node when you have OSX export configured?

[Calinou]

Would it be possible to display a warning next to Particle2D node when you have OSX export configured?

I don't think reading the list of export presets from code is possible either (especially if it'd require editor/ code dependency in a scene/ file, which we no longer allow).

[KoBeWi]

This doesn't require reading export presets in particles, just passing the information from editor to the node. It's possible to do it using some hacks, e.g. putting a metadata in ProjectSettings file or SceneTree. Hacks are ok for editor-only code.

EDIT:
If anyone thinks of implementing this for whatever reason, it's only relevant for 3.x branch.