flutter_embedder VS bevy

I'm actually working on this as a side project (here).

I personally settled on Flutter. It's a modern declarative UI framework by Google that was designed for mobile apps, but it can also do desktop and web these days. It can be used as a library using its embedder API that can render to Vulkan, Metal and OpenGL. So, it can be embedded in a wgpu context (here's my prototype for that based on wgpu/Vulkan and winit). Flutter uses Dart for UI programming, which is fine for me, since a lot of iteration is necessary for that, and Flutter allows Dart code to be hot reloaded during development (so you just have to save your file and the running application is updated automatically, keeping all of its state intact). Rust wouldn't be able to do that at the moment. Web support is trivial, because Flutter Web allows integrating HTML elements between its UI layers. I can simply insert a canvas there and link that to wgpu.

Here's the repository.

I've started writing my own Flutter shell here that runs on all desktop and mobile systems Flutter supports without any platform-specific code paths. The trick is that I'm delegating the responsibility for platform-specific code to a generic library (winit in this case) and so keep it out of my codebase.

I've started a project for using Rust for a shell using the Flutter Engine's embedder interface, so it’s trivial to integrate Rust into the system. It’s available here.

What I'm currently looking into is using Flutter for UI drawing instead of web tech. It has a built-in compositing API that allows interleaving native drawing with its surfaces and has a Vulkan renderer. The only downside is that you have to write a shell for it that maps the native platform to its APIs, which is very underdocumented and needs a lot of code, for example for handling keyboard input. Here's my progress so far. It comes with shells for all of its supported platforms, but they all use OpenGL or Metal (for iOS/macOS).

I need to check out how well this combines with my Rust-based Flutter shell.

I personally spent a significant part of my spare time in the last few months researching this topic, and came to the conclusion that for my (very similar) project, I'd like to use Flutter and Dart for the UI and Rust with wgpu (maybe bevy) for the rendering backend. I'm working on an integration for native platforms (so everything except web) right now, it's available in earliest alpha here. Web itself is trivial, because you can simply mount a separate canvas as a platformview and use that for wgpu, completely separating the two worlds.

Unfortunately, I'm really busy these days so I don't have any time for any more projects. I'm currently working on this project, which allows using the UI framework Flutter together with wgpu, so I'd say that it's adjacent to your project.

Bevy. A very young engine where you need to write the game entirely in Rust—that was appealing. But fatal flaws overshadowed everything: no editor, the engine brutally enforces the ECS approach, and the game's architecture must literally bend to fit this paradigm. So, you won't migrate to another engine at all—you just throw away all the code and start from scratch.

Missing one of the best choices as long as "maturity" isn't on the top of your list: Bevy - https://bevyengine.org/

Game engine written in Rust, leveraging ECS in almost every place and way, with a really capable WASM export option. Wrestling ECS for the first time might take you some time, but in my experience helps you keep game code as clean and decoupled as game code could be.

I don't see WASM/WebGPU changing anything when it comes to gaming, as an industry, personally. 3d visualizations and interactive websites? Yeah definitely a nice improvement over WebGL 2, if years late.

WebGPU is pretty far behind what AAA games are using even as of 6 years ago. There's extra overhead and security in the WebGPU spec that AAA games do not want. Browsers do not lend themselves to downloading 300gb of assets.

Additionally, indie devs aren't using Steam for the technical capabilities. It's purely about marketshare. Video games are a highly saturated market. The users are all on Steam, getting their recommendations from Steam, and buying games in Steam sales. Hence all the indie developers publish to Steam. I don't see a web browser being appealing as a platform, because there's no way for developers to advertise to users.

That's also only indie games. AAA games use their own launchers, because they don't _need_ the discoverability from being on Steam. So they don't, and avoid the fees. If anything users _want_ the Steam monopoly, because they like the platform, and hate the walled garden launchers from AAA companies.

(I work on high end rendering features for the Bevy game engine https://bevyengine.org, and have extensive experience with WebGPU)

I was working through an example in the repo for the Bevy game engine recently and came across this code

That's possible. I did spend quite a bit of time tinkering with compiler flags, and followed the recommendations.

Some notes I found just now seems to agree with my results, though: https://github.com/bevyengine/bevy/issues/3978#issuecomment-...

I cannot recommend immediate mode GUI programming based on the limitations I've experienced working with egui.

egui does not support putting two widgets in the center of the screen: https://github.com/emilk/egui/issues/3211

It's really easy to get started with immediate mode, it's really easy to bust out some UI, but the second you start trying to involve dynamically resized context and responsive layouts -- abandon all hope. The fact it has to calculate everything in a single pass makes these things hard/impossible.

... that said, I'm still using it for https://ant.care/ (https://github.com/MeoMix/symbiants) because it's the best thing I've found. I'm crossing my fingers that Bevy's UI story (or Kayak https://github.com/StarArawn/kayak_ui) become significantly more fleshed out sooner rather than later. Bevy 0.13 should have lots more in this area though (https://github.com/bevyengine/bevy/discussions/9538)

I've also been enjoying building My First Game™ in Bevy using ECS. The community around Bevy really shines, but Flecs (https://github.com/SanderMertens/flecs) is arguably a more mature, open-source ECS implementation. You don't get to write in Rust, though, which makes it less cool in my book :)

I'm not very proud of the code I've written because I've found writing a game to be much more confusing than building websites + backends, but, as the author notes, it certainly feels more elegant than OOP or globals given the context.

I'm building for WASM and Bevy's parallelism isn't supported in that context (yet? https://github.com/bevyengine/bevy/issues/4078), so the performance wins are just so-so. Sharing a thread with UI rendering suuucks.

If anyone wants to browse some code or ask questions, feel free! https://github.com/MeoMix/symbiants

These days, some game engines have done pretty well at making compute shaders easy to use (such as Bevy [1] -- disclaimer, I contribute to that engine). But telling the scientific/financial/etc. community that they need to run their code inside a game engine to get a decent experience is a hard sell. It's not a great situation compared to how easy it is on NVIDIA's stack.

[1]: https://github.com/bevyengine/bevy/blob/main/examples/shader...

This is the API you need: https://github.com/bevyengine/bevy/pull/9774