TeaVM support in third-party extensions

[czyzby]

TeaVM backend should be mostly able to compile pure Java libraries that are specifically made for GWT as long as no native code is involved. As an example, it is able to use the GWT Box2D plugin due to its pure Java implementation.

Ideally, all libraries that currently support GWT via additional dependencies should be tested whether they can be compiled by the TeaVM backend and if they require any GWT-specific artifacts. For example, Artemis-odb provides a GWT library that should be checked against the TeaVM compiler.

@tommyettinger @xpenatan

[tommyettinger]

I'm not especially familiar with how TeaVM works, but most of the times I need GWT-specific code, I use its super-source feature to replace one implementation with a GWT-specific one, which happens automatically based on the .gwt.xml file configuration. It's entirely possible this isn't needed on TeaVM. Do we need :sources dependencies for TeaVM like GWT needs?

[xpenatan]

Hey, about ":sources". I guess no. teavm just need the compiled classes.

[czyzby]

I mostly meant modules that have separate artifacts for GWT. Artemis is a good example, since it includes net.onedaybeard.artemis:artemis-odb in core and net.onedaybeard.artemis:artemis-odb-gwt in GWT. To fully support third-party extensions in the TeaVM backend, such libraries have to be checked if they compile in TeaVM and if the GWT-specific dependencies are necessary to run them.

Now that I think about it, it would be cool if each library defined the platforms that it supports, so you could display warnings whenever one of your platforms cannot use a specific dependency. But it's even more work to provide that info for all existing stuff. ;')

[czyzby]

@xpenatan Do you have a list of libraries that you've already tested against TeaVM? I already included dependencies for FreeType, Bullet and Box2D.

[xpenatan]

gdx gltf works with teavm. There is just a issue now with the new snapshots related to /classes and teavm-native classpath that I'm trying to resolve.