ObjectLayerCulling

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ObjectLayerCulling : MonoBehaviour
{
    private Camera mainCamera;
    private List<GameObject> taggedObjects;

    private void Start()
    {
        mainCamera = Camera.main; // get the main camera
        taggedObjects = new List<GameObject>(GameObject.FindGameObjectsWithTag("Objects")); // find all objects with the tag "Objects"
    }

    private void Update()
    {
        foreach (GameObject obj in taggedObjects)
        {
            if (obj == null)
            {
                continue; // skip to the next object if this one is null
            }

            // Check if object is within camera view
            Vector3 screenPoint = mainCamera.WorldToViewportPoint(obj.transform.position);
            bool onScreen = screenPoint.z > 0 && screenPoint.x > 0 && screenPoint.x < 1 && screenPoint.y > 0 && screenPoint.y < 1;

            // If object is not within camera view, deactivate it
            if (!onScreen)
            {
                // Check if any part of the mesh is visible on screen
                Renderer renderer = obj.GetComponent<Renderer>();
                if (renderer != null)
                {
                    bool isVisible = GeometryUtility.TestPlanesAABB(GeometryUtility.CalculateFrustumPlanes(mainCamera), renderer.bounds);
                    if (isVisible)
                    {
                        obj.SetActive(true);
                    }
                    else
                    {
                        obj.SetActive(false);
                    }
                }
            }
            // If object is within camera view, activate it
            else
            {
                obj.SetActive(true);
            }
        }
    }
}