using UnityEngine;
using UnityEditor;
using System.Linq;

public class LODSetup : EditorWindow
{
    [MenuItem("Tools/Setup LODs")]
    public static void SetupLODs()
    {
        foreach (var selectedObject in Selection.gameObjects)
        {
            SetupLODForGameObject(selectedObject);
        }
    }

    private static void SetupLODForGameObject(GameObject go)
    {
        // Get all child objects that have _LOD in their name.
        var lodObjects = go.transform.Cast<Transform>()
            .Where(t => t.name.Contains("_LOD"))
            .OrderBy(t => t.name)
            .Select(t => t.gameObject)
            .ToArray();

        if (lodObjects.Length == 0)
            return;

        var lodGroup = go.AddComponent<LODGroup>();
        var lods = new LOD[lodObjects.Length];

        for (int i = 0; i < lodObjects.Length; i++)
        {
            lods[i] = new LOD(1.0f / (i + 1), lodObjects[i].GetComponentsInChildren<Renderer>());
        }

        lodGroup.SetLODs(lods);
        lodGroup.RecalculateBounds();
    }
}