Rust Game Template Project

This project is an exploration of the Rust game development ecosystem, structured as a reusable template. The goal is to showcase how various crates can be integrated to build a game, hopefully making it easier for others to get started with Rust-based game development. If you're new to Rust or game development, this template can serve as a useful starting point.

Features

• Game Engine: Built on top of Bevy, a data-driven game engine that emphasizes simplicity and modularity.
• Input Management: Handled with leafwing-input-manager for flexible input control.
• Physics: Powered by bevy_rapier for 2D/3D physics simulations.
• Level Editing: Support for LDtk, allowing one to design levels in a user-friendly editor and easily integrate them into your game.

Build & Platform Support

The game is packaged with Nix, this ensures reproducible builds and complete deployments across different platforms:

• Linux: Supports x86_64 and aarch64 architectures.
• macOS: Works on both Intel and Apple Silicon.
• WebAssembly (WASM): The game can be compiled to run in browsers.

You can try the game online here: Play Now.

Automated Testing

An automated end-to-end (e2e) system test ensures the game runs correctly by verifying that the main menu appears on startup. The NixOS e2e test framework:

1. Spawns a virtual machine with an X server enabled.
2. Launches the game.
3. Uses OCR (Optical Character Recognition) to detect the main menu text, confirming successful startup.

Development

The following sections explain how to obtain a development shell, what tools to use during development, and lastly what to run before committing.

Development Shell

There are two to obtain a development shell: you can configure direnv to be dropped in a development shell automatically when you enter the directory (recommended) or do it manually.

Automatic Development Shell using direnv

First, you will have to install direnv, by adding it to your Nix/NixOS configuration or using your package manager.

Afterward, add a .envrc file to the root of the project:

touch .envrc
echo "use flake" >> .envrc

Next, enable direnv for this project:

direnv allow

Obtaining a Development Shell Manually

Run:

nix develop

Inside a Development Shell

Inside the development shell, you can use cargo as usual during development.

Before you Commit

Because Nix gives us gives us a high degree of reproducibility, by building our project and running the checks locally and making them succeed, we can be very certain it will pass the pipeline too.

Build

You can explore the buildable outputs of any flake project by running:

nix flake show

To build e.g. game you can then run:

nix build .#game

Run the Checks

To run all the "checks" of this project, like formatting, lint, audit, etc. checks, run:

nix flake check

To run a single check e.g. the format check, run:

nix build .#checks.<system>.treefmt

Format

Code for the whole project tree can be formatted by running nix fmt from the project's root or anywhere in the tree, but be warned that it will only format code inside the sub-tree.

The nix fmt command currently formats all the Rust and Nix code in the tree. To add support for more languages you'll have to adjust the treefmt attribute-set in the flake.nix accordingly. A list of already supported formatters can be found here.