Engine-Pong/Game/Behaviours/MovementBallBehaviour.cs

using System;

using Syntriax.Engine.Core;
using Syntriax.Engine.Physics2D;
using Syntriax.Engine.Physics2D.Abstract;

namespace Pong.Behaviours;
public class MovementBallBehaviour : BehaviourOverride
{
    public Vector2D StartDirection { get; private set; } = Vector2D.Zero;
    public float Speed { get; set; } = 500f;

    private IRigidBody2D rigidBody = null!;

    public MovementBallBehaviour(Vector2D startDirection, float speed)
    {
        StartDirection = Vector2D.Normalize(startDirection);
        Speed = speed;
    }
    public MovementBallBehaviour() { }

    protected override void OnFirstActiveFrame()
    {
        if (!BehaviourController.TryGetBehaviour(out IRigidBody2D? foundRigidBody))
            throw new Exception($"{nameof(IRigidBody2D)} is missing on {GameObject.Name}.");
        if (!BehaviourController.TryGetBehaviour(out ICollider2D? foundCollider))
            throw new Exception($"{nameof(ICollider2D)} is missing on {GameObject.Name}.");

        foundRigidBody.Velocity = StartDirection * Speed;
        foundCollider.OnCollisionDetected += OnCollisionDetected;

        rigidBody = foundRigidBody;
    }

    private void OnCollisionDetected(ICollider2D collider2D, CollisionDetectionInformation information)
    {
        rigidBody.Velocity = rigidBody.Velocity.Reflect(information.Normal);
    }
}