Flame Engine Quick Reference

Component Lifecycle

onLoad() → onMount() → update(dt)/render(canvas) → onRemove()

Method	Timing	Purpose
onLoad()	Once, async	Resource loading, initialization
onMount()	On tree addition	Set parent/game references
update(dt)	Every frame	State update (dt = delta seconds)
render(canvas)	Every frame	Draw to screen
onRemove()	On removal	Cleanup

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Core Classes

Class	Purpose	Key Properties/Methods
FlameGame	Game root	pauseEngine(), resumeEngine(), overlays
World	Hosts game components	add(), children
Component	Base component	add(), remove(), children, parent
PositionComponent	Position/size/rotation	position, size, angle, anchor, scale
SpriteComponent	Static sprite	sprite, paint
SpriteAnimationComponent	Animation	animation, playing
CameraComponent	Camera control	follow(), moveTo(), setBounds(), viewport

Shape Components

• RectangleComponent - Rectangle
• CircleComponent - Circle
• PolygonComponent - Polygon

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Collision Detection

Enable

// Add to Game or World
class MyGame extends FlameGame with HasCollisionDetection {}

Hitbox Types

Hitbox	Purpose
RectangleHitbox	Rectangular collision area
CircleHitbox	Circular collision area
PolygonHitbox	Polygon (convex only)
ScreenHitbox	Screen boundaries
CompositeHitbox	Composite hitbox

Collision Callbacks

class MyComponent extends PositionComponent with CollisionCallbacks {
  @override
  void onCollisionStart(Set<Vector2> points, PositionComponent other) {}

  @override
  void onCollision(Set<Vector2> points, PositionComponent other) {}

  @override
  void onCollisionEnd(PositionComponent other) {}
}

Collision Type (Performance)

• CollisionType.active - Checks against all hitboxes
• CollisionType.passive - Only checked by active (better performance)
• CollisionType.inactive - Ignored

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Effects System

Effect	Purpose	Example
MoveEffect.to()	Move to target	Character movement
MoveEffect.by()	Move by offset	Relative movement
RotateEffect.to()	Rotate to angle	Direction change
ScaleEffect.to()	Change size	Zoom in/out
ColorEffect	Color/opacity	Hit effect
SequenceEffect	Sequential execution	Complex animation
OpacityEffect	Opacity	Fade in/out

Effect Controller

MoveEffect.to(
  Vector2(100, 100),
  EffectController(duration: 1.0, curve: Curves.easeInOut),
);

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Camera & World

Camera Methods

Method	Purpose
follow(target)	Follow target
moveTo(position)	Move to coordinates
moveBy(offset)	Move by offset
stop()	Stop movement
setBounds(shape)	Limit camera movement
canSee(component)	Check visibility

Viewport Types

Viewport	Purpose
MaxViewport	Expand to max space (default)
FixedResolutionViewport	Fixed resolution + aspect ratio
FixedAspectRatioViewport	Fixed aspect ratio, scales
FixedSizeViewport	Fixed size

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Bridge Packages

flame_riverpod (State Management)

// Game
class MyGame extends FlameGame with RiverpodGameMixin {}

// Component
class MyComponent extends Component with RiverpodComponentMixin {
  @override
  void onMount() {
    super.onMount();
    final state = ref.watch(myProvider);
  }
}

// Widget
RiverpodAwareGameWidget<MyGame>(
  game: game,
)

flame_forge2d (Physics Engine)

class MyGame extends Forge2DGame {}

class MyBody extends BodyComponent {
  @override
  Body createBody() {
    final shape = CircleShape()..radius = 10;
    final fixtureDef = FixtureDef(shape);
    final bodyDef = BodyDef(type: BodyType.dynamic);
    return world.createBody(bodyDef)..createFixture(fixtureDef);
  }
}

flame_audio (Audio)

// Sound effects
FlameAudio.play('explosion.mp3');

// BGM
FlameAudio.bgm.play('background.mp3');
FlameAudio.bgm.stop();
FlameAudio.bgm.pause();
FlameAudio.bgm.resume();

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Common Patterns

Add Component

await add(MyComponent());  // In onLoad
add(MyComponent());        // In update

Remove Component

removeFromParent();  // Self
component.removeFromParent();  // Other component

Query Children

children.query<Enemy>();  // Find by type
componentsAtPoint(position);  // Find by position
findByKey(ComponentKey.named('player'));  // Find by key

Priority (Z-order)

class MyComponent extends PositionComponent {
  MyComponent() : super(priority: 10);  // Higher = rendered on top
}

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Official Docs

• Flame Docs
• Components
• Collision
• Effects
• Camera