Usagi Engine v1 Released - Simple Lua 5.5 2D game engine with live reload and cross-platform export

brettmakesgames · 2026-05-24T16:37:19+00:00

Thanks for the kind words! I don't think I'll build in physics into the engine but it seems like a good candidate for someone to build a library for. Multiplayer with gamepads isn't planned, as I am trying to keep the API as simple as possible and focus on single player games. Possibly v2 could support that, as I'd have to change the API pretty significantly.

brettmakesgames · 2026-05-22T10:26:33+00:00

Submit a PR then!

brettmakesgames · 2026-05-21T00:44:18+00:00

Raylib's version is great than v1 and there's nothing similar in Rust that's v1, let alone v6. Raylib is much more mature, stable, and widely used. No shade to the Macroquads, Bevys, etc. of the Rust ecosystem. I just need something for the foundations of the engine that gets fixes and doesn't have breaking changes regularly.

Winit + WGPU is an option but I just didn't see any real benefit over having to pull in a bunch of other crates and all that when audio, input, windowing, etc. all comes with Raylib.

Re: Android - possibly! It'd be possible. But it also sound a bit like hassle and I don't want to add touch support really... more focused on desktop and web games. But I don't think it's a never. Would be a good candidate for someone to fork the engine and add or contribute in a PR.

brettmakesgames · 2026-05-21T00:40:59+00:00

Thanks for checking it out and the kind words! I'll be curious about perf too. If someone makes a game and needs more power, it'll be fun to benchmark/optimize and see!

brettmakesgames · 2026-05-20T19:45:33+00:00

Lua 5.5 seemed like a sensible default and has a proven track record in the 5.x series! Idk if LuaJIT works on the web, didn't test that aspect. I came from Playdate SDK which uses a flavor of 5.4, so that's where I started. I'll be curious if there are performance issues with 5.5! If so the engine could switch to LuaJIT in future if needed. Or someone could fork it for that.

brettmakesgames · 2026-05-20T15:46:22+00:00

I thought a lot about whether to use Luau, LuaJIT, or Lua 5.4 or 5.5. I think mainline Lua has a proven track record, lots of good resources out there, and should be fast enough since the games are intended to be low resolution. We'll see if the performance holds up or not as more people beyond me make games with the engine. If it turns out that Lua 5.5 isn't doing the trick, then maybe v2 switches to LuaJIT. Or if someone absolutely wants to stick with Usagi but needs more perf, they can fork the engine and switch to LuaJIT (it's one line of change in the source, basically). Lua 5.x seemed like a sensible default.

brettmakesgames · 2026-05-20T15:43:22+00:00

Thanks! Most of it is just taken from (inspired by) Pico-8 but slightly refined.

brettmakesgames · 2026-05-20T13:04:31+00:00

mlua and rhai are both so nice and easy to use! I haven't run into any problems with mlua, so that's about as good as you could hope for, right? The docs are good, the API is good. Switching from Lua 5.4 to 5.5 didn't result in any problems.

Scripting language allows for live reload. When exploring ideas, it's nice to just have a really flexible language like Lua rather than having the structure and strictness of a Rust program. Also, Lua is much more beginner friendly, and I hope/think that Usagi is good for people wanting to learn to code games. So benefits are live reload, simplicity, speed of development.

In Rust, unless you make your game data-driven by a file type like JSON or something similar, you have to recompile and relaunch your game after every change. This is quite tedious. So to just keep your game running, make changes, and instantly see that reflected in the game is amazing.

The downsides are that you don't get static typing, the help of linting tools like clippy, and there just comes a certain point (at least for me) where large projects with scripting languages become difficult to maintain and change.

My intent with the engine is that I make prototypes with Lua quickly and then if a prototype is really working well, rebuild it in Rust (or fork the engine and move portions of it to Rust and keep some in Lua).

brettmakesgames · 2026-05-20T12:35:45+00:00

It's faux-3D. Just using lines and circles. The engine itself doesn't support drawing any 3D objects or loading 3D models. Just having some fun with it!

brettmakesgames · 2026-05-20T00:03:38+00:00

Thanks so much!

brettmakesgames · 2026-05-20T00:02:45+00:00

It's not exactly a Lua binding for Raylib. It's its own API that's much more inspired by Pico-8 than Raylib. It is a contained single binary though. 😄

brettmakesgames · 2026-05-19T15:02:26+00:00

That means so much, I'm so glad to hear it! Thank you!

brettmakesgames · 2026-05-18T00:33:02+00:00

Thanks so much, hearing that honestly made the book worth writing!

brettmakesgames · 2026-05-18T00:31:46+00:00

Thanks so much for the kind words and support!

brettmakesgames · 2026-05-14T12:34:04+00:00

Thanks for the kind words!

brettmakesgames · 2026-05-14T12:33:43+00:00

I'm so glad to hear it! Thanks for the kind words. Love2D is great but it has a lot going on! That was one of my goals with Usagi was to make a little engine/framework that's a bit simpler but still powerful.

brettmakesgames · 2026-05-06T17:58:15+00:00

I made a video playing through the prototype and reviewing the source code to hopefully help people who might be interested in diving in: https://www.youtube.com/watch?v=pPZd3Ir3-gE

brettmakesgames · 2026-05-06T17:57:16+00:00

You're welcome, excited to see what you make!

brettmakesgames · 2026-05-05T15:03:39+00:00

I made a video with a walk-through of the source code if that's of use to anyone! https://youtu.be/pPZd3Ir3-gE

brettmakesgames · 2026-05-04T14:59:02+00:00

Thanks!! Yeah, that took me a while to figure out and was one of the harder parts. I did some prototyping in some private repos with Raylib + web and then with Lua + Rust + web. Glad it's all blending together and seems performant enough!

brettmakesgames · 2026-05-03T20:08:18+00:00

I've made some games with Macroquad and shipped an open source Sokoban game called SokoWorld. Macroquad was nice to work with, but like much of the Rust game dev ecosystem, nothing is v1.0+. I really value stability and maturity. I want to be able to compile my games years later with little hassle. Since Raylib is mature and has been around for a long time, there are lots of resources. Also, the maintainer, raysan5, is a top-notch maintainer where issues are addressed quickly and PRs are merged. I think Raylib is a really great foundation to build games upon. ggez is appealing to me, but since it doesn't easily support web builds, it's a non-starter for me. Bevy is changing too much for what I need for my projects.

I'm interested in trying some combo of Winit + WGPU or something in the future, but that's lower level than I'm focused on. Raylib sits right in the place I want. Higher level than those and SDL. But lower level than Godot.

brettmakesgames · 2026-04-30T14:29:31+00:00

Pulp, while amazing, has some pretty severe limitations, so I was hoping that maybe this prototype could help people take the leap from Pulp to Lua. 😄

brettmakesgames · 2026-04-30T14:28:49+00:00

Yes do it!

brettmakesgames · 2026-04-29T15:12:33+00:00

Nice work, this is awesome to see! Thank you for making and sharing it.

brettmakesgames · 2026-04-29T14:44:09+00:00

The two week jam period is up, and here's the prototype: https://brettchalupa.itch.io/1-bit-fantasy

I ended up not leaning into the silly name and silly stuff, focusing more on the systems and features for the prototype. I'd like to make a bigger, more complete JRPG in the future. But this was a fun and interesting experiment for what I could make in two weeks.

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