Odin + Raylib + Hot Reload template

This is an Odin + Raylib game template with Hot Reloading pre-setup. It makes it possible to reload gameplay code while the game is running. I have made as a mix of Karl Zylinski Odin Template and Randy Prime Blueprint

Run build_hot_reload.sh to create game_hot_reload.bin (located at the root of the project) and game.so (located in build/hot_reload). Note: It expects odin compiler to be part of your PATH environment variable.
Run game_hot_reload.bin, leave it running.
Make changes to the gameplay code in source/game.odin. For example, change the line rl.ClearBackground(rl.BLACK) so that it instead uses rl.BLUE. Save the file.
Run build_hot_reload.sh, it will recompile game.so.
The running game_hot_reload.bin will see that game.so changed and reload it. But it will use the same Game_Memory (a struct defined in source/game.odin) as before. This will make the game use your new code without having to restart.

Note, in step 4: build_hot_reload.sh does not rebuild game_hot_reload.bin. It checks if game_hot_reload.bin is already running. If it is, then it skips compiling it.

Release builds

Run build_release.sh to create a release build in build/release. That bin does not have the hot reloading stuff, since you probably do not want that in the released version of your game. This means that the release version does not use game.so, instead it imports the source folder as a normal Odin package.

build_debug.sh is like build_release.sh but makes a debuggable executable, in case you need to debug your non-hot-reload-exe.

Web build

build_web.sh builds a release web executable (no hot reloading!).

Web build requirements

Emscripten. Download and install somewhere on your computer. Follow the instructions here: https://emscripten.org/docs/getting_started/downloads.html (follow the stuff under "Installation instructions using the emsdk (recommended)").
Recent Odin compiler: This uses Raylib binding changes that were done on January 1, 2025.

Web build quick start

Point EMSCRIPTEN_SDK_DIR in build_web.sh/sh to where you installed emscripten.
Run build_web.sh/sh.
Web game is in the build/web folder.

Note

build_web.sh is for windows, build_web.sh is for Linux / macOS.

Warning

You can't run build/web/index.html directly due to "CORS policy" javascript errors. You can work around that by running a small python web server:

Go to build/web in a console.
Run python -m http.server
Go to localhost:8000 in your browser.

For those who don't have python: Emscripten comes with it. See the python folder in your emscripten installation directory.

Build a desktop executable using build_desktop.sh/sh. It will end up in the build/desktop folder.

There's a wrapper for read_entire_file and write_entire_file from core:os that can files from assets directory, even on web. See source/utils.odin

Web build troubleshooting

See the README of the Odin + Raylib on the web repository for troubleshooting steps.

Assets

You can put assets such as textures, sounds and music in the assets folder. That folder will be copied when a release build is created and also integrated into the web build.

The hot reload build doesn't do any copying, because the hot reload executable lives in the root of the repository, alongside the assets folder.

RAD Debugger

You can hot reload while attached to RAD Debugger. Attach to your game_hot_reload executable, make code changes in your code editor and re-run the the build_hot_reload script to build and hot reload.

Atlas builder

The template works nicely together with my atlas builder. The atlas builder can build an atlas texture from a folder of png or aseprite files. Using an atlas can drastically reduce the number of draw calls your game uses. There's an example in that repository on how to set it up. The atlas generation step can easily be integrated into the build bat / sh files such as build_hot_reload.sh

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