Bevy Game Engine

Bevy Game Engine

Expert knowledge for developing games with Bevy, the data-driven game engine built in Rust with a focus on ergonomics, modularity, and performance.

When to Use This Skill

Core Expertise

Bevy Architecture

• Entity Component System (ECS): Data-oriented design with entities, components, and systems
• Plugin System: Modular game organization with reusable plugins
• Schedules: System ordering and execution timing
• Resources: Global singleton data accessible to systems
• Events: Typed message passing between systems
• States: Game state management and transitions

Rendering

• 2D Rendering: Sprites, sprite sheets, text rendering, 2D cameras
• 3D Rendering: PBR materials, meshes, lighting, shadows, cameras
• UI: bevy_ui for in-game interfaces
• Shaders: Custom WGSL shaders and render pipelines

Reference Files

The ECS core, project setup, and the command set below are everything a first pass needs. Follow one link when the task calls for it — nothing under references/ is loaded unless you open it.

Key Capabilities

ECS Fundamentals

use bevy::prelude::*;

// Components are plain data structs
#[derive(Component)]
struct Player;

#[derive(Component)]
struct Health(f32);

#[derive(Component)]
struct Velocity(Vec2);

// Spawn entities with components
fn spawn_player(mut commands: Commands) {
    commands.spawn((
        Player,
        Health(100.0),
        Velocity(Vec2::ZERO),
        SpriteBundle {
            transform: Transform::from_xyz(0.0, 0.0, 0.0),
            ..default()
        },
    ));
}

// Systems query for components
fn move_player(
    time: Res<Time>,
    mut query: Query<(&Velocity, &mut Transform), With<Player>>,
) {
    for (velocity, mut transform) in &mut query {
        transform.translation += velocity.0.extend(0.0) * time.delta_seconds();
    }
}

App Structure

use bevy::prelude::*;

fn main() {
    App::new()
        // Default plugins (window, rendering, input, etc.)
        .add_plugins(DefaultPlugins)
        // Custom plugins
        .add_plugins(GamePlugin)
        // Resources
        .insert_resource(GameSettings::default())
        // Startup systems (run once)
        .add_systems(Startup, setup)
        // Update systems (run every frame)
        .add_systems(Update, (
            player_movement,
            collision_detection,
            update_score,
        ))
        .run();
}

// Organize with plugins
pub struct GamePlugin;

impl Plugin for GamePlugin {
    fn build(&self, app: &mut App) {
        app.add_systems(Startup, spawn_player)
           .add_systems(Update, player_input);
    }
}

Essential Commands

# Create new Bevy project from the official template (recommended — ships an
# opinionated app skeleton, CI, and release profiles). See rust-plugin's
# cargo-generate skill.
cargo generate --git https://github.com/TheBevyFlock/bevy_new_2d --name my_game

# Or start from an empty crate
cargo new my_game
cd my_game
cargo add bevy

# Run with fast compile times (debug)
cargo run

# Run with optimizations
cargo run --release

# Enable dynamic linking for faster compiles (dev only)
cargo run --features bevy/dynamic_linking

# Common dev dependencies
cargo add bevy_egui           # Debug UI
cargo add bevy_rapier2d       # 2D physics
cargo add bevy_rapier3d       # 3D physics
cargo add bevy_asset_loader   # Asset loading helpers
cargo add leafwing-input-manager  # Advanced input

Agentic Optimizations

For detailed ECS patterns, advanced queries, and system scheduling, see the bevy-ecs-patterns skill.