Odin + Raylib + Hot Reload template (+ Atlas Builder!)

Support me at https://www.patreon.com/karl_zylinski

See branch atlas-animation-example for example on how to use atlas builder and atlased animations.

Description

This is an Odin + Raylib game template with Hot Reloading pre-setup. My game projects tend to have some things in common, so I made this template so I can get up and running quickly.

This template is compatible with Windows, macOS and Linux. The instructions are mostly for Windows, but there is a non-windows section that explains the differences.

build_hot_reload.bat will build game.dll from the odin code in the game folder. It will also build game.exe from the code in the directory main_hot_reload. When you run game.exe it will load game.dll and start the game. In order to hot reload, make some changes to anything that is compiled as part of game.dll and re-run build_hot_reload.bat. game.exe will notice that game.dll changed and reload it. The state you wish to keep between reloads goes into the Game_Memory struct in game.odin.

There is also a build_release.bat file that makes a game_release.exe that 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.dll, instead it imports the game directory as a normal Odin package.

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

There are also some additional files with some helpers that I find useful. See Optional files below.

Setup and usage

Copy raylib.dll from your_odin_compiler/vendor/raylib/windows to the root of this repo.
Run build_hot_reload.bat to compile game.exe and game.dll. Note: It expects odin compiler to be part of your PATH environment variable.
Run game.exe
Make changes to the gameplay code (for example, make changes in the proc update or draw in game/game.odin)
Run build_hot_reload.bat again while game.exe is running, it will recompile game.dll
game.exe will reload game.dll but use the same Game_Memory (a struct defined in game/game.odin) as before.

Non-Windows

The template also supports Linux and MacOS, all mentions of .bat scripts have an equivalent .sh script, and the game is built as game.bin instead of game.exe.

Unlike Windows, there is no need to copy any Raylib library to the root of this repo.

Sublime Text

There's sublime project called project.sublime-project in case you use Sublime Text. It comes with a build system, you should be able to open the project, select the build system (Main Menu -> Tools -> Build System -> Game template) and then compile + run the game by pressing F7/Ctrl+B/Cmd+B. Edit the project file to change the name of the build system.

VS Code

Included there are Debug and Release tasks for VS Code. If you install the CodeLLDB extension, it's possible to Debug the project code with the included Debug task.

A task to build and hot reload is also included, build, run and rebuild with Ctrl+B or Command Palette -> Task: Run Build Task.

Optional files

Only game.odin and math.odin are required to compile the game DLL. You can delete the other .odin files in the root directrory of the repository if you wish. They are there because they contain things I often use in all projects. Most of them have a description at the top of the file, explaining what it contains.

Atlas builder

The atlas_builder subfolder contains a program that builds a texture atlas from separate aseprite and png files. You can look in build_hot_reload.bat for more info on how to enable it. The atlas builder outputs both an atlas PNG file as well as an atlas.odin file that contains metadata about where in the atlas the images are.

The atlas builder is meant to be run before the game DLL is compiled. Then, in your gameplay you can use atlas_textures in atlas.odin to know where in the atlas your textures ended up. Load the atlas.png using rl.LoadTexture() and then draw using it, something like:

atlas_rect := atlas_textures[.Some_Texture]
rl.DrawTextureRec(atlas_texture, atlas_rect, some_position, rl.WHITE)

For aseprite files with multiple frames animations will be outputted, which you find in the array atlas_animations of atlas.odin.

See readme.md in the atlas_builder folder for more info and the branch atlas-animation-example for an example on how to use the atlas builder in practice.

Demo streams

Streams that start from this template:

CAR RACER prototype: https://www.youtube.com/watch?v=KVbHJ_CLdkA
"point & click" prototype: https://www.youtube.com/watch?v=iRvs1Xr1W6o
Metroidvania / platform prototype: https://www.youtube.com/watch?v=kIxEMchPc3Y
Top-down adventure prototype: https://www.youtube.com/watch?v=cl8EOjOaoXc

Projects based on this template

Name	Type	Description
Subfolders	Extended Template	Adds sub folders for built binaries and the game DLL's source code

Got a project based on this template? I'd gladly have it on this list! It can be a game based on the template or an extension/spinoff of the template. Just send me a link on Discord or on karl@zylinski.se, or PR the entry into this README 😻

Questions?

Ask questions in my gamedev Discord: https://discord.gg/4FsHgtBmFK

I have a blog post about Hot Reloading here: http://zylinski.se/posts/hot-reload-gameplay-code/

karl-zylinski/odin-raylib-hot-reload-game-template