gdnative VS hecs

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/

For Rust, I really like Bevy's, but it gets too much in the way. I'd probably use macroquad instead with something like hecs (I tried macroquad with Bevy ECS and didn't go well).

The question arises from seeing a plethora of projects using ECS: hecs , Bevy , specs, legion

My current design has struct Core that is basically "everything you need to save in a savefile", it has a hecs ECS (which needs a bit of boilerplate the hecs docs show you how to write to serialize it), and a bunch of simpler gamestate stuff like the discovered map positions, the current player etc. Everything is tree-like and serializes into a text file. Entity handles from hecs serve as "pseudo-pointers" that can represent cycle-like structures without running into endless cycles.

Out of the other Rust engines we've tried I think Macroquad was the most interesting option, and even though I've only made a few small projects in it worked extremely well and was what I'd expect from a game framework. While working in Bevy I felt like it was "writing fun Rust", but it wasn't really making a game. Macroquad on the other hand got immediately out of the way, and using it together with hecs was a painless experience where the whole time I felt like I was working on "the game" rather than "building systems that are invisible to the player".

The last crate worth mentioning is probably hecs for ECS, which we don't really use as heavily as some ECS fans would assume, but it made working around some problems between GDScript and Rust easier by storing things in ECS, passing around handles and querying ECS instead. Initially we did this with a global object and lots of state (which we still use for some things), but as the number of "things" grew it became easier to put it into ECS.

I use the awesome Vulkano for rendering and computation, and Rapier for simple physics. Contour is used for the initial shapes, but rapier forms the physics colliders from it. Hecs is used as well. And you might recognize Egui as gui :). I gotta say, I'm starting to be pretty happy with the rust ecosystem overall.

In the hecs documentation there is a section, Why Not ECS?. In it, the author states, "If your game will have few types of entities, consider a simpler architecture such as storing each type of entity in a separate plain Vec."

Usually, what I do is creating large, robust components in Rust. In my game, most of the logic lives inside the Factory node, which inside holds a full ECS (currently using https://github.com/Ralith/hecs) as well as other associated resources. This node takes care of holding the state and simulating all the machines in the factory and their interactions.

Generally, spatially-indexable data gets special treatment in games. (See Why not ECS for example, from the hecs ECS library.)

That impl basically says that Leftwalker is a System (or implements a System interface, to use a different parlance). Why exactly do Systems need lifetime is something better asked of the authors of the ECS library the tutorial uses. (personally I use hecs https://github.com/Ralith/hecs instead because I find it easier to use, no lifetime in sight :p)