Engine-Pong/Game/Physics2D/Collider2DAABBBehaviour.cs

using System;
using System.Collections.Generic;

using Microsoft.Xna.Framework;

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

namespace Syntriax.Engine.Physics2D;

public class Collider2DAABBBehaviour : BehaviourOverride, ICollider2D
{
    public AABB AABBLocal { get; set; } = null!;
    public AABB AABBWorld { get; private set; } = null!;

    private IRigidBody2D? _rigidBody2D = null;
    private List<Vector2> vertices = new List<Vector2>(4);
    private IReadOnlyList<Vector2>? _verticesReadOnly = null;

    public IRigidBody2D? RigidBody2D
    {
        get
        {
            if (_rigidBody2D is null)
                BehaviourController.TryGetBehaviour(out _rigidBody2D);

            return _rigidBody2D;
        }
    }

    public Action<ICollider2D, ICollider2D>? OnCollisionPreResolve { get; set; } = null;

    public Action<IAssignableTransform>? OnTransformAssigned { get => GameObject.OnTransformAssigned; set => GameObject.OnTransformAssigned = value; }
    ITransform IAssignableTransform.Transform => Transform;
    public bool Assign(ITransform transform) => GameObject.Assign(transform);

    public IReadOnlyList<Vector2> Vertices { get { if (_verticesReadOnly is null) _verticesReadOnly = vertices.AsReadOnly(); return _verticesReadOnly; } }

    public bool CheckCollision(Vector2 point)
    {
        return AABBWorld.Inside(point);
    }

    public void Recalculate()
    {
        AABBWorld = new AABB(
            AABBLocal.LowerBoundary + Transform.Position,
            AABBLocal.UpperBoundary + Transform.Position
        );

        vertices.Clear();
        vertices.Add(AABBWorld.LowerBoundary);
        vertices.Add(new(AABBWorld.LowerBoundary.X, AABBWorld.UpperBoundary.Y));
        vertices.Add(AABBWorld.UpperBoundary);
        vertices.Add(new(AABBWorld.LowerBoundary.Y, AABBWorld.UpperBoundary.X));
    }

    public Collider2DAABBBehaviour(Vector2 lowerBoundary, Vector2 upperBoundary)
    {
        AABBLocal = new AABB(lowerBoundary, upperBoundary);
        AABBWorld = new AABB(lowerBoundary, upperBoundary);
    }

    public Collider2DAABBBehaviour()
    {
        AABBLocal = new(Vector2.Zero, Vector2.Zero);
        AABBWorld = new(Vector2.Zero, Vector2.Zero);
    }
}