[펌] OcclusionCulling2D

using UnityEngine;

public class OcclusionCulling2D : MonoBehaviour
{
    [System.Serializable] public class ObjectSettings
    {
        [HideInInspector] public string title;
        public GameObject theGameObject;

        public Vector2 size = Vector2.one;
        public Vector2 offset = Vector2.zero;
        public bool multiplySizeByTransformScale = true;

        public Vector2 sized { get; set; }
        public Vector2 center { get; set; }
        public Vector2 TopRight { get; set; }
        public Vector2 TopLeft { get; set; }
        public Vector2 BottomLeft { get; set; }
        public Vector2 BottomRight { get; set; }
        public float right { get; set; }
        public float left { get; set; }
        public float top { get; set; }
        public float bottom { get; set; }

        public Color DrawColor = Color.white;
        public bool showBorders = true;
    }

    public ObjectSettings[] objectSettings = new ObjectSettings[1];

    private Camera camera;
    private float cameraHalfWidth;

    public float updateRateInSeconds = 0.1f;

    private float timer;

    void Awake(){ 
        camera = GetComponent<Camera>();
        cameraHalfWidth = camera.orthographicSize * ((float)Screen.width / (float)Screen.height);

        foreach(ObjectSettings o in objectSettings){
           o.sized = o.size * (o.multiplySizeByTransformScale ? new Vector2(Mathf.Abs(o.theGameObject.transform.localScale.x), Mathf.Abs(o.theGameObject.transform.localScale.y)) : Vector2.one);
            o.center = (Vector2)o.theGameObject.transform.position + o.offset;

            o.TopRight = new Vector2(o.center.x + o.sized.x, o.center.y + o.sized.y);
            o.TopLeft = new Vector2(o.center.x - o.sized.x, o.center.y + o.sized.y);
            o.BottomLeft = new Vector2(o.center.x - o.sized.x, o.center.y - o.sized.y);
            o.BottomRight = new Vector2(o.center.x + o.sized.x, o.center.y - o.sized.y);

            o.right = o.center.x + o.sized.x;
            o.left = o.center.x - o.sized.x;
            o.top = o.center.y + o.sized.y;
            o.bottom = o.center.y - o.sized.y;
        }
    }

    void OnDrawGizmosSelected()
    {
        foreach(ObjectSettings o in objectSettings)
        {
            if(o.theGameObject)
            {
                o.title = o.theGameObject.name;

                if(o.showBorders)
                {
                    o.TopRight = new Vector2(o.center.x + o.sized.x, o.center.y + o.sized.y);
                    o.TopLeft = new Vector2(o.center.x - o.sized.x, o.center.y + o.sized.y);
                    o.BottomLeft = new Vector2(o.center.x - o.sized.x, o.center.y - o.sized.y);
                    o.BottomRight = new Vector2(o.center.x + o.sized.x, o.center.y - o.sized.y);
                    Gizmos.color = o.DrawColor;
                    Gizmos.DrawLine(o.TopRight, o.TopLeft);
                    Gizmos.DrawLine(o.TopLeft, o.BottomLeft);
                    Gizmos.DrawLine(o.BottomLeft, o.BottomRight);
                    Gizmos.DrawLine(o.BottomRight, o.TopRight);
                }
            }
        }
    }
    
    void FixedUpdate()
    {
        timer += Time.deltaTime;
        if(timer > updateRateInSeconds) timer = 0;
        else return;

        float cameraRight = camera.transform.position.x + cameraHalfWidth;
        float cameraLeft = camera.transform.position.x - cameraHalfWidth;
        float cameraTop = camera.transform.position.y + camera.orthographicSize;
        float cameraBottom = camera.transform.position.y - camera.orthographicSize;

        foreach(ObjectSettings o in objectSettings)
        {
            if(o.theGameObject)
            {
                bool IsObjectVisibleInCastingCamera = o.right > cameraLeft & o.left < cameraRight & // check horizontal
                                                      o.top > cameraBottom & o.bottom < cameraTop; // check vertical
                o.theGameObject.SetActive(IsObjectVisibleInCastingCamera);
            }
        }
    }
}

[출처] https://www.youtube.com/watch?v=hbBDqdoHUpE