PongFE/PongFE/Engines/BounceEngine.cs

using System.Numerics;
using Encompass;
using PongFE.Components;
using PongFE.Enums;
using PongFE.Messages;

namespace PongFE.Engines
{
    [Reads(
        typeof(BounceResponseComponent),
        typeof(VelocityComponent)
    )]
    [Receives(typeof(BounceMessage))]
    [Sends(typeof(UpdateVelocityMessage))]
    public class BounceEngine : Engine
    {
        public override void Update(double dt)
        {
            foreach (ref readonly var message in ReadMessages<BounceMessage>())
            {
                if (HasComponent<BounceResponseComponent>(message.Entity) && HasComponent<VelocityComponent>(message.Entity))
                {
                    ref readonly var velocityComponent = ref GetComponent<VelocityComponent>(message.Entity);

                    Vector2 newVelocity;
                    if (message.HitOrientation == HitOrientation.Horizontal)
                    {
                        newVelocity =
                            new Vector2(-velocityComponent.Velocity.X, velocityComponent.Velocity.Y);
                    }
                    else
                    {
                        newVelocity =
                            new Vector2(velocityComponent.Velocity.X, -velocityComponent.Velocity.Y);
                    }

                    SendMessage(new UpdateVelocityMessage(message.Entity, newVelocity));
                }
            }
        }
    }
}