cxx VS gdnative

There are cxx and autocxx, what else do you propose to do?

I would like to see a comparison of how this compares to Rust. In terms of interoperability it has Cxx (https://cxx.rs) to offer safe bindings to C++ but also has great support for Android, Linux and many other systems. You don't even need to hack together Windows bindings (as explained in the blog post) because Microsoft offers official bindings (https://crates.io/crates/windows). I'm not sure if I'd call it a superpower if any potential interoperability has to be written to be used (compared to it already being available). Or rather, in comparison to what is interoperability a Swift superpower? Certainly not C++ or C which can be used in a far wider set of targets.

We selected Qt as a cross-platform solution. The C++/Rust interface is the clunkiest and ugliest part of the application, and rather complex because some state is shared between several windows in the GUI and several threads in the backend, and any component might modify that state at any time, and updates have to be transmitted to the other components without introducing inconsistencies. Using cxx [1] helped a little, though.

The project began in 2020, and I'm not sure what I'd choose as a GUI framework today – definitely not Qt Widgets, though.

[1] https://cxx.rs/

If the build process for the C library isn't too involved I recommend using cxx bridge (https://cxx.rs/) and letting cargo handle the build and linking. cxx basically allows you to describe the bidirectional interface (although it sounds like you only need 1 direction, which is fine too) in Rust code and it provides a "good enough" API for compiling C code inside the build.rs file.

The tooling for the first kind -- calling Rust from another language -- is a bit less developed, and tends to rely on code generation that doesn't necessarily produce a natural C API. cbindgen, uniffi, cxx, and Diplomat all take this course.

I would like to utilize OMPL's functionality in Rust code, so I want to call into OMPL C++ code somehow in Rust. I've seen two (non-mutually-exclusive) options so far: - rust-cpp, which allows you to write C++ code in Rust within the cpp!() macro. - cxx, which allows you to define both sides of the FFI boundary manually (as opposed to bindgen's automatic generation).

I'm not sure how to do this in cxx; issues like https://github.com/dtolnay/cxx/issues/447 suggest that this isn't settled yet?

I use non-vendored dependencies for the Buck build in https://github.com/dtolnay/cxx.

There's also the cpp and cxx crates for doing C++/Rust interop, but they probably aren't appropriate to use in all cases. The C ABI is definitely the safest way to go unless you're really trying to marry Rust and C++ code bases, not just writing library bindings.

There's also cxx (can't vouch for it personally but it claims to make things a lot easier) https://github.com/dtolnay/cxx

It's a little less standard use, but Godot has been used to build application guis, which could be paired with rust bindings to implement app logic. I can't speak to reproducibility/scalability, but Godot's ui is extremely solid, and I'd probably choose that over Bevy until Bevy's ui progress matures.

Adding onto this, I successfully written a game in Godot using gdnative / gdext. I started with a split approach using gdscript and rust for CPU intensive but found that the API layer was slow at transferring large amounts of data (serialization?). I ended up rewriting it in all rust and it worked like a charm. I was able to target native and web assembly, the web assembly was much slower but worked on the browser.

Check this: https://github.com/tomuxmon/bevy_roguelike if you are still into bevy. Scheduling is a bit bork and I have not found time to port it to latest bevy. But most of the systems should work fine(if used on latest bevy). But again. If you want faster result go with something like Godot. In fact, just go with Godot. It is mature, easy to start, no lock in(free and MIT license), a lot of learning material. Also with Godot you can also use Rust https://godot-rust.github.io/. Ditch Unity (do not have time to explain 😅). Have fun!

Bevy Godot-Rust

> Same for Godot.

While likely true that it's "Unlikely to ever be as supported" as the 4 officially supported languages[0] ("GDScript, C#, and, via its GDExtension technology, C and C++."), Godot's GDExtension technology is specifically intended for use in adding support for other languages.

The most relevant tracking issue for Rust is presumably:

* <https://github.com/godot-rust/gdnative/issues/824>

Which links to:

* <https://github.com/godot-rust/gdextension>

[0] https://docs.godotengine.org/en/4.0/getting_started/step_by_...

...Godot v3.x has Rust support via godot-rust and Godot v4.0 is released as of this month?

I was curious, and looked it up. Nothing built in, but there's an interesting project that works with godot: https://godot-rust.github.io/

There's people working on it: https://godot-rust.github.io/