#Flame Signals

flame_signals offers a simple, type-safe mechanism to provide signals with or without data payloads between components in a FlameGame.

Follow this link for a simple example. This is the example in the github repo.

How To Use

Add To Game

To use flame_signals, start by adding the HasSignals mixin to your game class:

class SpaceGame extends FlameGame with HasSignals {
  //...
}

The mixin defines a Stream of type FlameSignal to adding and broadcasting the signals.

Define a signal class

Extend the base class FlameSignal to define one or more signal objects.

class MeteorDestroyedSignal extends FlameSignal {
  final Vector2 position;
  final double laserAngle;
  
  const MeteorDestroyedSignal({required this.position, required this.laserAngle});
}

class DecreaseMeteorCountSignal extends FlameSignal {}

Send a signal

Any component in the tree will be able to send a FlameSignal. Both the SendSignals and FlameSignalListenable mixins provide an addSignal method to send out a signal.

class Meteor extends Component with SendSignals {
  //...
  //...
  void onHitByLaser() {
    addSignal(MeteorDestroyedSignal(
      position: position,
      laserAngle: laser.angle,
    ));
  }
}

React to a signal received.

Components that need to react to game signal use the FlameSignalListenable mixin. A signal handler must be registered in the components onMount life cycle method.

This creates a subscription to the signal stream. When the component is removed from the component tree, the onRemove life cycle method cancels the subscription.

class MeteorManager extends Component with FlameSignalListenable {
  @override
  void onMount() {
    super.onMount();
    onSignal<MeteorDestroyedSignal>((signal) {
      _generateNewMeteor();
      _updateMeteorCount();
    });
  }
}

A component using the FlameSignalListenable mixin can also add signals.

class MeteorManager extends Component with FlameSignalListenable {
  @override
  void onMount() {
    super.onMount();
    onSignal<MeteorDestroyedSignal>((signal) {
      _generateNewMeteor();
      _updateMeteorCount();
    });
  }
  //...
  //...
  void _updateMeteorCount() {
    addSignal(DecreaseMeteorCountSignal());
  }
}

For more information

GitHub Repo

Example App (found in repo)