Steering Behaviors

Developed with 💙 by Very Good Ventures 🦄

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An implementation of steering behaviors for Flame Behaviors. See Steering Behaviors For Autonomous Characters by Craig Reynolds for an in-depth explanation

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Installation 💻

flutter pub add flame_steering_behaviors

Usage ✨

This package is built on top of the flame_behaviors, if you are not yet familiar with it, we recommend reading up on the documentation of that package first.

Steerable

If you want to apply steering behaviors to your entities you have to add the Steerable mixin to your entity class:

class MyEntity extends Entity with Steerable {
  /// Provide the max velocity this entity can hold.
  double get maxVelocity => 100;

  ...
}

The Steerable mixin provides a velocity value to your entity, this velocity will then be applied on each update cycle to your entity until the velocity becomes zero.

Steering Behaviors

Each algorithm defined by this project is available as a Behavior and you can add them to your steerable entities as you would with any behavior:

class MyEntity extends Entity with Steerable {
  MyEntity() : super(
    behaviors: [
      WanderBehavior(
        circleDistance: 200,
        maximumAngle: 45 * degrees2Radians,
        startingAngle: 0,
      )
    ]
  );

  ...
}

Some steering behaviors require information that is not always available on entity creation, when that happens we recommend using the entity's onLoad method:

class MyEntity extends Entity with Steerable {
  ...

  @override
  Future<void> onLoad() async {
    world.children.register<MyOtherEntity>();
    await add(
      SeparationBehavior(
        world.children.query<MyOtherEntity>(),
        maxDistance: 25,
        maxAcceleration: 1000,
      ),
    );
  }

  ...
}