Guide
Four ports of the same game, one per Clojure-family runtime, kept side by side so the differences are readable. The game itself is a pretext. What the repo is actually for is showing what changes when the same Clojure crosses into C four different ways, and what does not.
New here? getting-started.md gets one of the four on screen in a couple of minutes.
Read in this order the first time:
| Page | What it covers |
|---|---|
| getting-started.md | Install raylib, pick a port, run it, run it unattended. |
| architecture.md | Why four standalone copies rather than one library with four backends, and the shape inside each. |
| the-game.md | The half that barely changes. State, the frame step, tile-centre movement, the four ghost personalities. |
| crossing-to-c.md | The comparison. How each runtime reaches raylib, what each FFI will and will not carry, and what that costs. |
| drawing-pac-man.md | One shape, two implementations, and the angle convention that breaks silently. |
| running-unattended.md | Deadlines, screenshots, and why the clock is game time rather than wall time. |
Then the per-runtime pages, which assume the four above:
| Page | Runtime |
|---|---|
| babashka.md | babashka over babashka.ffi |
| clojure.md | Clojure on the JVM over raylib-clj, coffi and Panama |
| jank.md | jank over cpp/ interop |
| jolt.md | jolt over jolt.ffi |
And when you want to change something:
| Page | What it covers |
|---|---|
| contributing.md | The gate, why a rendered frame is one of them, and how to add a runtime. |
Each example directory also carries its own README.md, which is the short operational version: how to run it, what it needs installed, what bites.
Find your scenario
| Scenario | Pages to read |
|---|---|
| "I want to try this out" | Getting started |
| "I want to understand how it works" | Architecture, then the game |
| "I came for the FFI comparison" | Crossing to C, then the runtime page you care about |
| "Something renders wrong" | Drawing Pac-Man |
| "I want to contribute a change" | Contributing |
A note on what is measured here
Every claim in these pages about a runtime's behaviour was run rather than remembered, on macOS 15 and an Apple M1 Pro, in September 2026. Where a number appears, it came from a probe in this repo. Where something is described as failing, it failed and the error text is quoted. The versions in play were babashka 1.13.220, jank 0.1-alpha with raylib-sys 2026.09-3, jolt 0.8.10, and raylib 6.0 from Homebrew.
That matters most for the jank page. jank is alpha and moves quickly, so a constraint described there may have been lifted since.