add gruid buildingsystem

Assets/Scripts/BuildingManager.cs

@@ -0,0 +1,25 @@
+using UnityEngine;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine.Tilemaps;
+public class BuildingManager : MonoBehaviour
+{
+  public static List<Building> buildings { get; private set; } = new List<Building>();
+
+  public static Building GetBuildingByGridPosition(Vector3Int tilePosition)
+  {
+    foreach (Building building in buildings)
+    {
+      PlaceableObject po = building.placeableObject;
+      Vector3Int buildingPosition = building.GetGridPosition();
+      BoundsInt area = new BoundsInt(buildingPosition, po.GetSizeVector());
+      if (area.Contains(tilePosition))
+      {
+        return building;
+      }
+    }
+
+    return null;
+  }
+}