What is Bevy?

Bevy is an open-source modular game engine built in Rust, with a focus on developer productivity and performance.

WARNING

Bevy is still in the very early stages of development. APIs can and will change. Important features are missing. Documentation is non-existent. Please don't build any serious projects in Bevy unless you are prepared to be broken by api changes constantly.

Design Goals

• Provide a first class developer experience for both 2D and 3D games.
• Easy for newbies to pick up, but infinitely flexible for power users.
• Fast iterative compile times. Ideally less than 1 second for small to medium sized projects.
• Data-first game development using ECS (Entity Component System)
• Modular design: use only what you need ... replace what you don't like
• High performance and parallel architecture
• Use the latest and greatest rendering technologies and techniques

About

• Features: A quick overview of Bevy's features.
• Roadmap: The Bevy team's development plan.

Docs

• The Bevy Book: Bevy's official documentation. The best place to start learning Bevy.
• Bevy Rust API Docs: Bevy's Rust API docs, which are automatically generated from the doc comments in this repo.

Getting Started

We recommend checking out The Bevy Book for a full tutorial. You can quickly try out the examples by cloning this repo and running the following command:

# Runs the "scene" example
cargo run --example scene

Fast Compiles

Bevy can be built just fine using default configuration on stable Rust. However for really fast iterative compiles, you should use nightly Rust and rename .cargo/config_fast_builds to .cargo/config. This enables the following:

• Shared Generics: This feature shares generic monomorphization between crates, which significantly reduces the amount of redundant code generated (which gives a nice speed boost).
• LLD linker: Rust spends a lot of time linking, and LLD is much faster. This config swaps in LLD as the linker on Windows and Linux (sorry MacOS users ... LLD currently does not support MacOS). You must have lld installed, which is part of llvm distributions:
  • Ubuntu: sudo apt-get install lld
  • Arch: sudo pacman -S lld
  • Windows (using scoop package manager): scoop install llvm

Libraries Used

Bevy is only possible because of the hard work put into these foundational technologies:

• wgpu-rs: modern / low-level / cross platform graphics library inspired by Vulkan
• legion: a feature rich high performance ECS library
• glam-rs: a simple and fast 3D math library for games and graphics
• winit: cross platform window creation and management in Rust
• legion_transform: A hierarchical space transform system, implemented using Legion ECS
• spirv-reflect: Reflection API in rust for SPIR-V shader byte code

Additionally, we would like to thank the Amethyst, coffee, ggez, and Piston projects for providing solid examples of game engine development in Rust. If you are looking for a Rust game engine, it is worth considering all of your options. Each engine has different design goals and some will likely resonate with you more than others.