Odin + Raylib starter with hot reload, save-triggered rebuilds, and an in-game debug overlay. Ships as native desktop (macOS, Windows) and web (itch.io) at 1280×720.

Built on top of karl-zylinski/odin-raylib-hot-reload-game-template (MIT). See LICENSE.

• Odin compiler on PATH.
• macOS: fswatch for watch.sh — brew install fswatch.
• Windows: nothing extra — watch.bat uses built-in PowerShell.
• Web build: Emscripten SDK.

./build_hot_reload.sh run   # build and launch
./watch.sh                  # in a second terminal: rebuild on save

build_hot_reload.bat run
watch.bat

1. Install emsdk. The scripts look in $HOME/repos/emsdk (macOS) and c:\SDK\emsdk (Windows) by default. If yours lives elsewhere, either edit EMSCRIPTEN_SDK_DIR at the top of build_web.sh / .bat, or just put emcc on your PATH.
2. ./build_web.sh or build_web.bat.
3. cd build/web && python3 -m http.server and open http://localhost:8000.

You can't open build/web/index.html directly — browser CORS rules block wasm loading from file://.

game_hot_reload.bin / .exe is a host that stays running. source/game.odin compiles to a shared library (game.dylib / .dll) in build/hot_reload/, and the host reloads it whenever the file changes on disk. Game_Memory is preserved across reloads — tweak proc bodies, constants, or add new procs without losing game state.

If you change the size of Game_Memory, the host detects it and calls game_init from scratch. One-time state-reset per struct change.

watch.sh / watch.bat re-runs the build script on every .odin save so the full loop is: save in your editor → game updates in ~1 second.

source/
  game.odin                    reloadable game logic
  main_hot_reload/             dev host
  main_release/                desktop release entry
  main_web/                    emscripten entry + JS glue
assets/                        sprites, sounds, music (empty; add yours here)
vendor/raylib/wasm/            prebuilt wasm libs for web build
build_hot_reload.{sh,bat}      dev build
build_release.{sh,bat}         optimized desktop build
build_web.{sh,bat}             wasm build
watch.{sh,bat}                 save-triggered rebuild
ols.json                       OLS config (portable, shared)
project.sublime-project        Sublime Text build system
.zed/launch.json               Zed debug config (gitignored, per-machine)

Install the ols language server. ols.json is auto-picked-up; ols discovers its core / vendor collections by running odin root. Debug via .zed/launch.json (LLDB targeting the hot-reload binary).

Install LSP + LSP-odin via Package Control. Open project.sublime-project. Ctrl/Cmd+B triggers build_hot_reload. Compile errors are click-navigable.

Attach to game_hot_reload.exe for native debugging with hot reload. The build script outputs a fresh PDB per reload, so the debugger stays in sync across swaps.

draw_debug_overlay in source/game.odin uses raygui (already part of vendor:raylib). Values live inside Debug_State which is nested in Game_Memory, so tunings survive hot reload. Add more controls by extending the struct:

rl.GuiCheckBox({16, 180, 16, 16}, "god mode", &g.debug.god_mode)
rl.GuiSlider({70, 200, 120, 16}, "spawn rate",
    fmt.ctprintf("%.1fs", g.debug.spawn_rate),
    &g.debug.spawn_rate, 0.1, 5)

See raygui.odin in Odin's vendor:raylib for the full control list.

1280×720 on both desktop and web.

• Desktop: rl.InitWindow(1280, 720, ...) in game_init_window.
• Web: canvas is locked at 1280×720 in source/main_web/index_template.html with image-rendering: pixelated and CSS max-width/height: 100vw/vh for letterboxed scaling inside itch's iframe.

PIXEL_WINDOW_HEIGHT :: 180 sets the camera zoom — the game renders as if the viewport were 180 units tall (a 4× upscale at 720p). Tweak this to change the pixel-art feel.

• Desktop build: ./build_release.sh / build_release.bat → build/release/ (optimized, no hot-reload host, assets folder copied alongside the binary).
• Web build: ./build_web.sh / build_web.bat → build/web/. Zip the contents and upload as an HTML5 build on itch.io.

vendor/raylib/wasm/libraylib.a and libraygui.a are committed to this repo because Homebrew's Odin package ships an empty vendor/raylib/wasm/ directory, and other Odin distributions are inconsistent. If the Odin toolchain updates and the raylib ABI shifts, re-fetch from upstream:

curl -L https://raw.githubusercontent.com/odin-lang/Odin/master/vendor/raylib/wasm/libraylib.a -o vendor/raylib/wasm/libraylib.a
curl -L https://raw.githubusercontent.com/odin-lang/Odin/master/vendor/raylib/wasm/libraygui.a -o vendor/raylib/wasm/libraygui.a

Template foundation: karl-zylinski/odin-raylib-hot-reload-game-template. Hot-reload design walkthrough: http://zylinski.se/posts/hot-reload-gameplay-code/