optimise instance access

Assets/Engine/Runtime/Engine.cs

@@ -13,18 +13,7 @@ namespace EscapeRoomEngine.Engine.Runtime
     public class Engine : MonoBehaviour
     {
         public static EngineTheme Theme => Instance.theme;
-        public static Engine Instance
-        {
-            get
-            {
-                if (_foundEngine == null)
-                {
-                    _foundEngine = FindObjectOfType<Engine>();
-                }
-                return _foundEngine;
-            }
-        }
-        private static Engine _foundEngine;
+        public static Engine Instance { get; private set; }
 
         public delegate void UpdateUIHandler();
         public event UpdateUIHandler UpdateUIEvent;
@@ -45,6 +34,8 @@ namespace EscapeRoomEngine.Engine.Runtime
 
         private void Awake()
         {
+            Instance = this;
+            
             Measure.Clear();
 
             _puzzles = new List<PuzzleModuleDescription>(theme.puzzleTypes);
@@ -57,6 +48,8 @@ namespace EscapeRoomEngine.Engine.Runtime
             _playSpaceOrigin.transform.localPosition = new Vector3(-theme.playSpace.x / 2f, 0, -theme.playSpace.y / 2f);
         }
 
+        #region Generation
+
         public void GenerateRoom()
         {
             Logger.Log("Generating room...", LogType.RoomGeneration);
@@ -123,6 +116,8 @@ namespace EscapeRoomEngine.Engine.Runtime
             room.AddSpace(space, exit);
         }
 
+        #endregion
+
         public void HidePreviousRoom(bool destroy = true)
         {
             if (NumberOfRooms > 2)