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;
    public float SpeedUpMultiplier { get; set; } = .0125f;

    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;
    }

    protected override void OnUpdate()
    {
        if (rigidBody.Velocity.MagnitudeSquared <= 0.01f)
            return;

        Vector2D speedUp = rigidBody.Velocity.Normalized * (float)Time.Elapsed.TotalMilliseconds;
        rigidBody.Velocity += speedUp * SpeedUpMultiplier;
    }

    private void OnCollisionDetected(ICollider2D collider2D, CollisionDetectionInformation information)
    {
        // if (information.Left.BehaviourController.GameObject == GameObject)
        if (Syntriax.Engine.Core.Math.Abs(information.Normal.Dot(Vector2D.Right)) > .25)
            rigidBody.Velocity = information.Left.Transform.Position.FromTo(information.Right.Transform.Position).Normalized * rigidBody.Velocity.Magnitude;
        else
            rigidBody.Velocity = rigidBody.Velocity.Reflect(information.Normal);
    }
}