Game Dev Tools

Reusable Bevy game development utilities for 2D games

A collection of battle-tested game development utilities extracted from real game projects. Built for Bevy 0.17+.

✨ Features

• 🎥 Camera Effects: Screen shake, bloom, cinematic controls
• 💥 Particle System: Explosions, smoke, trails, and custom effects
• 🎵 Audio Management: Easy sound effects and music playback
• 🌌 Parallax Backgrounds: Multi-layer scrolling with automatic wrapping
• ❤️ Health System: Health, lives, and damage tracking
• 🎮 Input Utilities: Mouse world position tracking, fullscreen toggle
• 🚀 Physics Helpers: Space physics, velocity system, distance-based cleanup

🚀 Quick Start

Add to your Cargo.toml:

[dependencies]
game-dev-tools = "0.1"
bevy = "0.17"

Basic setup:

use bevy::prelude::*;
use game_dev_tools::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugins(GameDevToolsPlugin)
        .add_systems(Startup, setup)
        .add_systems(Update, gameplay)
        .run();
}

fn setup(mut commands: Commands) {
    // Setup camera with cinematic effects
    camera::setup_cinematic_camera(&mut commands);
}

fn gameplay(
    mut commands: Commands,
    mut shake: ResMut<ScreenShake>,
    keyboard: Res<ButtonInput<KeyCode>>,
) {
    if keyboard.just_pressed(KeyCode::Space) {
        // Trigger screen shake
        shake.trigger(30.0, 0.5);

        // Spawn explosion particles
        spawn_explosion_particles(&mut commands, Vec2::ZERO, 10, 1.0);
    }
}

📚 Feature Guide

🎥 Screen Shake

Add dramatic impact to your game with configurable screen shake:

fn collision_system(mut shake: ResMut<ScreenShake>) {
    // Light shake
    shake.trigger(15.0, 0.2);

    // Heavy shake
    shake.trigger(50.0, 0.8);

    // Check if shaking
    if shake.is_active() {
        // Do something while shaking
    }
}

💥 Particle System

Create stunning visual effects:

fn spawn_effects(mut commands: Commands) {
    // Explosion particles
    spawn_explosion_particles(&mut commands, position, 20, 1.5);

    // Custom particle
    commands.spawn((
        Sprite { /* ... */ },
        Transform::from_translation(position.extend(0.0)),
        Particle::new(
            1.0,  // lifetime
            Color::srgb(1.0, 0.5, 0.0),  // start color
            Color::srgba(1.0, 0.0, 0.0, 0.0),  // end color
            10.0,  // start size
            2.0,   // end size
        ),
        ParticleBehavior::explosion(),
        Velocity(Vec2::new(100.0, 100.0)),
    ));
}

Preset particles:

• Particle::explosion_spark() - Bright explosion sparks
• Particle::smoke() - Expanding smoke clouds
• ParticleBehavior::explosion() - Gravity + drag
• ParticleBehavior::floating() - Gentle floating debris

🎵 Audio System

Simple audio management with volume controls:

fn shoot_system(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    audio_settings: Res<AudioSettings>,
    audio_state: Res<AudioState>,
) {
    play_sound_effect(
        &mut commands,
        &asset_server,
        &audio_settings,
        "sounds/laser.ogg",
        0.8,  // volume multiplier
        &audio_state,
    );
}

Built-in keyboard controls:

• M - Toggle mute
• +/- - Adjust volume

🌌 Parallax Backgrounds

Multi-layer scrolling backgrounds that follow the camera:

fn setup_background(mut commands: Commands) {
    // Far background
    commands.spawn((
        Sprite { /* ... */ },
        Transform::from_xyz(0.0, 0.0, -100.0),
        ParallaxLayer {
            speed_multiplier: 0.1,  // Slow movement (far away)
            layer_depth: -100.0,
            wrap_distance: 2000.0,
            original_position: Vec2::ZERO,
        },
    ));

    // Close foreground
    commands.spawn((
        Sprite { /* ... */ },
        Transform::from_xyz(0.0, 0.0, -10.0),
        ParallaxLayer {
            speed_multiplier: 0.8,  // Fast movement (close)
            layer_depth: -10.0,
            wrap_distance: 1000.0,
            original_position: Vec2::ZERO,
        },
    ));
}

❤️ Health System

Track health and lives for any entity:

fn setup_player(mut commands: Commands) {
    commands.spawn((
        Sprite { /* ... */ },
        Health::new(100.0),
        Lives::new(3),
    ));
}

fn damage_system(mut query: Query<(&mut Health, &mut Lives)>) {
    for (mut health, mut lives) in query.iter_mut() {
        // Take damage
        let is_dead = health.take_damage(25.0);

        if is_dead {
            // Health depleted, lose a life
            let game_over = lives.take_damage();

            if !game_over {
                // Restore health
                health.current = health.max;
            }
        }

        // Check health percentage
        let hp_percent = health.percentage();

        // Heal
        health.heal(10.0);
    }
}

🚀 Physics System

Space-like physics with momentum and drag:

fn setup_ship(mut commands: Commands) {
    commands.spawn((
        Sprite { /* ... */ },
        SpacePhysics {
            max_thrust: 500.0,
            drag_coefficient: 0.98,  // 2% drag per frame
            max_speed: 600.0,
            ..default()
        },
        Velocity(Vec2::ZERO),
    ));
}

fn movement_system(
    mut query: Query<&mut SpacePhysics>,
    keyboard: Res<ButtonInput<KeyCode>>,
) {
    for mut physics in query.iter_mut() {
        let mut thrust = Vec2::ZERO;

        if keyboard.pressed(KeyCode::KeyW) {
            thrust.y = 1.0;
        }

        physics.acceleration = thrust * physics.max_thrust;
    }
}

// Velocity is automatically applied by the plugin

🎮 Input Utilities

Get mouse position in world coordinates:

fn aiming_system(
    mouse_pos: Res<MouseWorldPos>,
    player_query: Query<&Transform, With<Player>>,
) {
    if let Ok(player_transform) = player_query.get_single() {
        let direction = mouse_pos.0 - player_transform.translation.truncate();
        let angle = direction.y.atan2(direction.x);
        // Use angle for aiming
    }
}

Built-in keyboard shortcuts:

• F11 - Toggle fullscreen
• F12 - Show FPS (requires FrameTimeDiagnosticsPlugin)

🛠️ Configuration

Customize the framework for your game:

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .insert_resource(GameDevConfig {
            window_width: 1920.0,
            window_height: 1080.0,
            max_projectile_distance: 3000.0,
            max_entity_distance: 2000.0,
            max_particle_distance: 1500.0,
        })
        .add_plugins(GameDevToolsPlugin)
        .run();
}

📦 What's Included

Components

• Health - Health tracking with damage/heal
• Lives - Life system
• Velocity - 2D velocity
• SpacePhysics - Space-like movement with momentum
• Projectile - Projectile with damage and optional lifetime
• Particle - Animated particle with color/size interpolation
• ParticleB behavior - Gravity, drag, and rotation for particles
• ParallaxLayer - Parallax scrolling layer
• CinematicCamera - Camera with effects

Resources

• ScreenShake - Global screen shake controller
• AudioSettings - Master, SFX, and music volume
• AudioState - Current audio state
• MouseWorldPos - Mouse position in world space
• CameraMovement - Camera velocity tracking
• GameDevConfig - Framework configuration

Systems

All systems are automatically added by GameDevToolsPlugin:

• unified_camera_shake_system - Applies screen shake
• update_particles - Updates particle effects
• apply_velocity - Applies velocity to transforms
• update_camera_movement - Tracks camera velocity
• update_parallax_layers - Updates parallax scrolling
• update_mouse_world_position - Updates mouse world position
• toggle_fullscreen - F11 to toggle fullscreen
• audio_controls - M to mute, +/- for volume

🎯 Examples

Run examples with:

cargo run --example basic_setup

See the examples/ directory for:

• basic_setup.rs - Minimal setup with screen shake
• particles.rs - Particle system showcase
• parallax.rs - Parallax background demo
• physics.rs - Space physics demo

🤝 Contributing

Contributions welcome! This library is extracted from real game projects and is designed to be practical and reusable.

📄 License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

🎮 Built With This

Share your game if you use this library! Open an issue to add yours here.

🔗 Links

• Documentation
• Crates.io
• Repository
• Bevy

Note: This library requires Bevy 0.17 or later.