antfarm VS bevy_mod_scripting

I've experienced a lot of these concerns while building https://github.com/MeoMix/symbiants

I have a simple question that maybe someone smarter than me can answer confidently:

If I want to build something akin to Dwarf Fortress (in terms of simulation complexity) as a browser-first experience - what stack should I choose?

Originally, I prototyped something out using React, PixiJS, and ReactPixi (https://github.com/MeoMix/antfarm). The two main issues I ran into were the performance of React's reconciler processing tens of thousands of entities when most weren't changing (despite heavy memoization) and GC lurching due to excess object allocations. My takeaway was that if I wanted to continue writing in JS/TS that I would need to write non-idiomatic code to avoid excess allocations and abandon React. This approach would result in me effectively creating my own engine to manage state.

I decided to not go that direction. I chose Rust because no GC is a language feature (especially good since GCs in WASM are heavy) and I chose Bevy because it seemed like a fairly structured way to mutate a large amount of code.

Progress has been slow for a lot of the reasons listed in this article. I've written a lot of this off to WASM being a new frontier for game dev and rationalized it by noting there's not a lot of complex simulation games running in browser (that I'm aware of). It's not clear to me if that's actually true, though.

I recently made an attempt at building a simulation game. I found it challenging even though I'm a seasoned software developer. I was finding that my experience in building out web apps, dashboards, and crud stacks didn't immediately lend itself to architecting a game properly. It feels like everything is business logic and it has been tough to see ways to tease out and modularize concepts. I don't know if I am making good trade-offs w.r.t performance and immutability. I find myself copying an entire "world" structure with every loop in an attempt to represent the world immutably, but I also seem to need to process changes serially as entities interact with one another inside the world. It doesn't matter that the world is immutable, I can't easily parallelize the simulation. Perhaps immutability is only making things harder, then?

I'm not too concerned about graphics or 3D math. I'm working in a 2D space with the most amateur of graphics. I'm interested in having some looming trade-offs pointed out to me so that I can make decisions with my architecture to best receive those trade-offs. I'm interested in design patterns that allow me to modularly enrich the complexity of my simulation.

If you're curious, https://github.com/MeoMix/antfarm/blob/main/src/util.ts Here is a file that became quite the dumping ground. I am not proud of this code. I had intended to tease out some utility methods which take a world and return a cloned and updated world. It's easy enough to separate out view concepts, and it's easy enough to separate out constructors, but all of the "interesting" simulation logic found its way to this dumping ground.

open source! https://github.com/MeoMix/antfarm

As someone who's become a core contributor to Bevy lately, while also doing contract work in Unity on the side, I obviously disagree with the idea that Rust isn't up to the task of game dev. The grass isn't greener on the Unity side, with a mountain of technical debt holding the engine back. (They're still using Boehm GC in 2024!) Bevy is a breath of fresh air just because it's relatively new and free of legacy. Using Rust instead of C++ is just one part of that. Bevy has a more modern design throughout: for instance, it has a relatively straightforward path to GPU-driven rendering in an integrated system, without having to deal with three incompatible render pipelines (BiRP, HDRP, URP).

What I find more interesting is the parts of the article that boil down to "Rust isn't the best language for rapid development and iteration speed". And that may well be true! I've long thought that the future of Bevy is an integrated Lua scripting layer [1]. You don't even need to get into arguments about the suitability of the borrow checker: it's clear that artists and designers aren't going to be learning Rust anytime soon. I'd like to see a world in which Rust is there for the low-to-mid-level parts that need performance and reliability, and Lua is there for the high-level logic that needs fast iteration, and it's all a nicely integrated whole.

Long-term, I think this world would actually put Bevy in a better place than the existing engines. Unity forces you into C# for basically everything, which is both too low-level for non-programmers to use and too high-level for performance-critical code (unless you have a source license, which no indie developer has). Unreal requires C++, which is even more difficult than Rust (IMO), or Blueprints, which as a visual programming language is way too high-level for anything but the simplest logic. Godot favors GDScript, which is idiosyncratic for questionable gain. I think Rust and Lua (or something similar) would put Bevy in a Goldilocks spot of having two languages that cover all the low-, mid-, and high-level needs well.

As for the other parts of the article, I disagree with the ECS criticism; ECS has some downsides, but the upsides outweigh the downsides in my view. I do agree that Bevy not having an official editor is an ongoing problem that desperately needs fixing. Personally, I would have prioritized the editor way higher earlier in Bevy's development. There is space_editor [2] now, which is something.

[1]: https://github.com/makspll/bevy_mod_scripting

[2]: https://github.com/rewin123/space_editor

So far, there are promising experiments like https://github.com/makspll/bevy_mod_scripting, but nothing's really caught fire in the community yet.

Interesting. Personally I find Rust-only pretty appealing, but people definitely have differing opinions: https://github.com/makspll/bevy_mod_scripting