GOO2D | A Low Level Flutter 2D Game Engine

Stateful Scene Graph

Build your game tree using standard Flutter widgets and sync* generators. Manage complex entity lifecycles with the familiar StatefulGameWidget pattern.

Entity-Component-System (ECS)

A flexible Entity Component System. Decouple your game logic into reusable components that can be attached and queried at runtime with ease.

Action-Based Input

Decouple game logic from physical hardware. Bind multiple keys or touch controls to logical actions, with built-in support for composite vectors and deadzones.

Stateful Scene Graph

Build complex game worlds by stacking GameWidgets. Goo2D leverages standard Flutter build methods and sync* generators to manage hierarchical entity trees.

@override
Iterable<Widget> build(BuildContext context) sync* {
  yield GameWidget(
    key: const GameTag('Player'),
    components: () => [
      ObjectTransform(),
      SpriteRenderer()..sprite = playerSprite,
      PlayerController(),
    ],
  );
}

class PlayerController extends Behavior with Tickable {
  @override
  void onUpdate(double dt) {
    // Decouple logic from representation
    final trans = getComponent<ObjectTransform>();
    final input = getComponent<PlayerInput>();
    
    trans.position += input.dir * 5.0 * dt;
  }
}

ECS

A flexible Entity Component System. Decouple your game logic into reusable components that can be attached and queried at runtime with ease.

Asset Management

Type-safe asset management with Enums. Built-in caching and reactive loading progress out of the box, ensuring your game assets are always organized.

enum MySprites with AssetEnum, TextureAssetEnum {
  ship, boss, explosion;
  @override
  AssetSource get source => 
    AssetSource.local("assets/sprites/$name.png");
}

// Reactive loading with streams
await for (final p in GameAsset.loadAll(MySprites.values)) {
  updateProgress(p.assetLoaded / p.assetCount);
}

final sheet = SpriteSheet.grid(
  texture: MySprites.explosion,
  columns: 8, rows: 8,
  ppu: 64.0,
);

// Instant frame access via coordinates
renderer.sprite = sheet[(0, 4)];

Sprite Sheets

Efficiently handle complex atlases and grids. Support for PPU (Pixels Per Unit) scaling and flexible pivot points for accurate rendering.

Collisions

Manage physical interactions without the widget tree overhead. Robust callbacks for hits, triggers, and screen-boundary events.

class Enemy extends Behavior with Collidable {
  @override
  void onCollision(CollisionEvent event) {
    // Precise filtering with GameTags
    if (event.other.gameObject.tag == const GameTag('Player')) {
      print("Hit player!");
      gameObject.destroy();
    }
  }
}

moveAction = createInputAction(
  name: 'move',
  type: InputActionType.value,
  bindings: [
    InputBinding.composite(
      up: game.input.keyboard.keyW,
      down: game.input.keyboard.keyS,
      left: game.input.keyboard.keyA,
      right: game.input.keyboard.keyD,
    ),
  ],
);

// Read 2D vector anywhere
final dir = moveAction.readValue<Offset>();

Input System

Modern, action-based input system. Bind multiple physical controls to a single logical action for cross-platform support.