bevy_webgl2 VS bevy

There was a rust game jam in September 2021 and some games are playable in the browser. In that game jam the most used game engine was the bevy game engine. But most of the games made in bevy were not made playable in the browser, the ones that were playable in the browser used a third-party bevy plugin called bevy_webgl2. However now bevy has been updated to version 0.6 that has new built in WASM support, so there seems to be no need for bevy_webgl2. Targeting WASM with bevy might mean that not all features of the engine are available, so you need to limit the game’s features used to the ones that are compatible with WASM.

For web assembly there is the unofficial bevy_webgl2 plugin. Official bevy web assembly support would probably use the wgpu webgl backend, which still needs some work, and is currently untested in bevy.

Thanks to bevy_webgl2, this is actually very straightforward. I just need to add the plugin WebGL2Plugin and disable the default features of Bevy to only enable the one available on Wasm.

Bevy has bevy_webgl2, which is supposed to enable a way to compile bevy for wasm and consequently run in a browser.

This is something that can certainly happen. In fact, this is exactly what happened with the Bevy engine, in which a total of 246 contributors agreed to relicense the engine, as explained in this blog post. However, in this case it was done for the good of the engine and its users.

I was crowing to my game dev buddy about how he (a Unity C-sharp developer) ought to check out Bevy and Rust because the Rust type system is friggin’ awesome!

Code examples: https://bevyengine.org/learn/book/getting-started/ecs/

License is Apache 2.0 OR MIT:

https://github.com/bevyengine/bevy/blob/main/LICENSE-APACHE

https://github.com/bevyengine/bevy/blob/main/LICENSE-MIT

For those who are more code centric and like rust, https://bevyengine.org/ is a good alternative to godot as far as open source goes.

It's become rather popular in the graphics (e.g. https://wgpu.rs/) and game dev (e.g. https://bevyengine.org/ ) spaces.

It's pretty popular for AWS Lambda functions.

Pretty popular for terminal / shell applications.

Definitely a great way to write wasm for compute or graphics intensive browser/web apps.

It seems like the best way to approach levels for a desktop build is to save and load scenes as shown in this example (which seems pretty straightforward), but as noted in that file, this doesn't work on WASM since there isn't a file system.

If you like you can copy what I did: https://github.com/tbillington/bevy_toon_shader, which I copied from https://github.com/bevyengine/bevy/ (just that my repo has was less stuff, so might be easier to copy from).

I think Rust for games has come really far. I will cite https://arewegameyet.rs/ "Almost. We have the blocks, bring your own glue.".

All the blocks are there and the language is really well suited to games.

On top of my head:

The pros:

- The crate ecosystem and the package manager makes it really easy to integrate any useful component such as pathfinding, spatial partitioning, graphics backend, audio system.. Most crates take a lot of effort to be cross-platform so I can develop on linux and not spend too much time debugging windows releases.

- The strong typing and algebraic data types makes expressing the game state very pleasant. I also found I was able to develop a very big game without too many bugs even though I don't write many tests.

- Ahead of time compilation + LLVM guarantees you won't have to optimise for weird things around a virtual machine. Rust gives you more control to optimise hot loops as you can go low-level.

- I find wgpu to be the perfect balance between ergonomics and power compared to Vulkan. OpenGL support through wgpu is also a nice addition for lower end devices.

- The Rust community is very helpful, you can often talk directly to crate maintainers

The cons:

- Compilation times, when compared to JITed languages such as C# can be very painful. It can be alleviated by buying a 3950X but I still often get 10-30s iteration times.

- The static nature of Rust means you often need a dynamism layer above to tweak stuff that can be awkward to manage. I made inline_tweak for this purpose but it's really far from how easy Unity makes it. https://github.com/Uriopass/inline_tweak

- Since Rust feels very ergonomic, you are tempted to write almost all game logic within it, so mod support feels very backwards to implement as you cannot really tweak "everything" like in Unity games. Thankfully "Systems" game like Factorio or Egregoria can be theoretically split into the "simulation" and the "entities" so mod can still have a great impact. Factorio is built in C++ so has the same problematic. Their Lua API surface is quite insane to be able to hook into everything. https://lua-api.factorio.com/latest/

Now, I have to talk about Bevy: https://bevyengine.org/. It did not exist when I started but it is a revolution in the Rust gamedev space. It is a very powerful 100% Rust game engine that makes you write game code in Rust too. It has incredible energy behind it and I feel like if I'd used Bevy from the start I wouldn't have had to develop many core engine systems. Its modular design is also incredibly pleasant as you can just replace any part you don't like with your own.

Learn how to draw sprites to the screen: https://github.com/bevyengine/bevy/blob/main/examples/2d/sprite.rs

Sadly while it was in a working state in time for release, we decided it needed a bit more bake time. You can check out the goals (and current progress) here! It will almost certainly land in the next release.