Crunch Physics Plugin

@dill-pixel/physics-crunch

A lightweight, grid-based AABB physics plugin for Dill Pixel games. Optimized for 2D platformers and games requiring precise, pixel-perfect collisions.

Features

• 🎯 Pixel-perfect AABB collision detection
• 📦 Grid-based spatial partitioning for efficient collision checks
• 🎮 Optimized for 2D platformers and action games
• 🧩 System supports Actors (Dynamic), Solids (Static), and Sensors (Trigger - Dynamic or Static)
• 🎨 Debug visualization tools
• 🔄 Object pooling support
• 🎬 Scene-based integration

Installation

npm install @dill-pixel/physics-crunch

Quick Start

// in dill-pixel.config.ts
defineConfig({
  //... other config
  plugins: ['crunch-physics', { autoLoad: false }],
});

// in your scene file
import { Scene } from 'dill-pixel';

// exports
export const plugins = ['crunch-physics']; // loads the plugin for your scene

// in your scene class
export default class MyCrunchScene extends Scene {
  get physics() {
    return this.app.getPlugin('crunch-physics') as ICrunchPhysicsPlugin;
  }

  async initialize() {
    await this.physics.initialize({
      gridSize: 32,
      gravity: 980,
      maxVelocity: 1000,
      debug: true,
    });

    // Create a player
    const player = physics.createActor({
      type: 'Player',
      position: [100, 100],
      size: [32, 64],
    });

    // Create a platform
    const platform = physics.createSolid({
      type: 'Platform',
      position: [0, 500],
      size: [800, 32],
    });

    // Create a coin pickup
    const coin = physics.createSensor({
      type: 'Coin',
      position: [200, 400],
      size: [32, 32],
    });
  }
}

Core Components

Actors

Dynamic entities that can move and collide (players, enemies, projectiles).

class Player extends Actor {
  update(dt: number) {
    // Custom movement logic
    if (this.app.input.isKeyDown('ArrowRight')) {
      this.velocity.x = 200;
    }
  }

  onCollide(result: CollisionResult) {
    // Handle collisions
    if (result.solid.type === 'Spikes') {
      this.die();
    }
  }
}

Solids

Static or moving collision objects (platforms, walls, obstacles).

// Create a moving platform
const platform = physics.createSolid({
  type: 'Platform',
  position: [100, 300],
  size: [200, 32],
});

// Animate platform movement
gsap.to(platform, {
  x: 500,
  duration: 2,
  yoyo: true,
  repeat: -1,
});

Sensors

Trigger zones for detecting overlaps (collectibles, checkpoints, damage zones).

class Coin extends Sensor {
  onActorEnter(actor: Actor) {
    if (actor.type === 'Player') {
      increaseScore(10);
      this.physics.removeSensor(this);
    }
  }
}

Groups

Containers for managing collections of entities that move together.

// Create a moving platform with hazards
const group = physics.createGroup({
  type: 'MovingPlatform',
  position: [100, 300],
});

const platform = physics.createSolid({
  type: 'Platform',
  size: [200, 32],
});

const spikes = physics.createSensor({
  type: 'Spikes',
  position: [0, -32],
  size: [200, 32],
});

group.add(platform);
group.add(spikes);

Advanced Features

Spatial Partitioning

The plugin uses a grid-based spatial partitioning system to efficiently handle collision detection:

// Configure grid size for your game's scale
physics.system.gridSize = 32;

Debug Visualization

Enable debug rendering to visualize collision boxes and the spatial grid:

physics.system.debug = true;

Collision Resolution

Custom collision handling with type-based filtering:

physics.system.setCollisionResolver((collisions) => {
  for (const collision of collisions) {
    // Handle specific collision types
    if (collision.type === 'Player|Enemy') {
      handlePlayerEnemyCollision(collision);
    }
  }
});

Performance Tips

• Use appropriate grid sizes for your game's scale
• Enable culling for large levels
• Utilize object pooling for frequently created/destroyed entities
• Use sensor overlaps instead of continuous collision checks where possible

License

MIT © Dill Pixel