PerspectiveCollider.cs

using UnityEngine;

namespace Renovation.Perspective
{
    public class PerspectiveCollider : MonoBehaviour
    {
        public PerspectiveLock Lock;
        private BoxCollider2D _collider;
        private Bounds bounds;

        private void Start()
        {
            var collider = GetComponent<BoxCollider2D>();
            bounds = collider.bounds;
            Destroy(collider);
            CreatePerspectiveCollider();
        }

        private void CreatePerspectiveCollider()
        {
            GameObject go = new GameObject();
            go.transform.parent = transform;
            go.name = "ProjectionCollider2D";
            go.layer = gameObject.layer;
            go.tag = gameObject.tag;
            _collider = go.AddComponent<BoxCollider2D>();
            UpdatePerspectiveCollider();
        }

        private void Update()
        {
            UpdatePerspectiveCollider();
        }

        private void UpdatePerspectiveCollider()
        {
            Vector2 projectedMin = Projection(bounds.min);
            Vector2 projectedMax = Projection(bounds.max);
            Vector2 center = (projectedMin + projectedMax) / 2;
            Vector2 size = (projectedMax - projectedMin);
            _collider.transform.position = center;
            _collider.size = size;
        }

        private Vector2 Projection(Vector3 point)
        {
            Vector3 delta = (point - Lock._otherCam.transform.position).normalized;
            float t = -Lock._otherCam.transform.position.z  / delta.z;
            return Lock._otherCam.transform.position + delta * t;
        }

        private void OnDestroy()
        {
            Destroy(_collider.gameObject);
        }
    }
}