ui-mock VS bevy

It's quite possible to develop Rust for Windows without using Windows.

Try my open source "ui-mock".[1] This is a test of the cross-platform stack. Just get the repository with "git clone", and make sure you have Rust installed for target "x86_64-pc-windows-gnu". See the Cargo.toml file for build instructions.

This is a game-type user interface. It's just some menus and a 3D cube. It doesn't do much, but it exercises all the lower levels. This allows debugging cross-platform problems in a simple environment. The main crates used are winit (cross-plaform window event handling), wgpu (cross-plaform GPU handling), rfd (cross-platform file dialogs), keychain (cross-platform password storage), egui (Rust-native menus and dialogs), and rend3 (safe interface to wgpu). For graphics, it uses Vulkan, so it will run on Windows back to the last release of Windows 7. Not Windows 95, though; it's 64-bit. It will also run under Wine, so you don't even need a Windows system to test.

My metaverse client uses the same stack. It's compiled on Linux, and runs on both Linux and Windows. So I'm building a high-performance 3D graphics program for Windows without even owning a Windows system or using any Microsoft software.

[1] https://github.com/John-Nagle/ui-mock

Profiling on the CPU side is well handled by tracy, which is a game-oriented profiler. My programs render-bench and ui-mock are prepped for Tracy, as is Rend3, so you can try it out on them.

ui-mock -- game GUI test fixture This exercises rfd->egui->rend3->wgpu. It's a game GUI with menus and dialogs, but no game behind it, just a 3D drawing of a cube. It's useful for making bugs in that stack repeatable. That's been helpful in wringing out obscure bugs in egui.

Egui works well with Rend3. Here's my example and library for that. It's a dummy game UI; no game, but brings up menus atop Rend3 3D. Egui is very low level. Each dialog takes a lot of code. Something to generate dialogs from some kind of template would be useful. I have many of those to do. Incidentally, does anyone have examples of good color themes for egui? The default is shades of black on black, which is a bit harsh. I'd like to see some examples where the aesthetics are better.

There's an attempt to make this work for Rust desktop applications. There's the winit crate, which does cross-platform windowing and event loops. There's egui, for menus and subwindows. There's rfd, for file dialogs, which are special for security reasons. And there's wgpu, for cross-platform 3D.

I'm using all of these in my ui-mock,[1] which is a GUI for a game without the game. It has 3D graphics with 2D GUI elements on top. I'm using this to shake down all the cross-platform problems for my metaverse client. My own code, which is 100% safe Rust, has no platform dependent code.

Results are pretty good. There's minor dirty laundry in those libraries, which has been reported to the various maintainers. Stuff like this:

- You can get a file dialog hidden behind the main window, which, in a full screen program, is a real problem. Mostly a Linux problem; works fine on Windows.

- Full screen on Windows mode under Wine 7 crashes Wine. Known Wine bug.

- Warnings from WGPU, but it works around all of them with some minor performance loss.

- Cross-platform packaging, to make a Windows installer without Windows, isn't implemented yet.

So, not big stuff. A lot of stuff works that you might not expect to work, such as profiling with tracy. Wgpu is taking care of Vulkan vs Apple's Metal. (Apple just had to Think Different, to the annoyance of everybody doing 3D.) Opening a web page in the default browser is cross-platform. You can cross-compile - I build the Windows version on Linux, without using any Microsoft tools.

With some more work, I could make this work on WASM and Android as well, but that requires some special casing, mostly because WASM doesn't have proper threads.

So cross-platform desktop development is working pretty well. Most of the problems I'm running into would not appear in a more typical application.

[1] https://github.com/John-Nagle/ui-mock

I have a Rend3/Egui/WGPU program, https://github.com/John-Nagle/ui-mock

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