Fixed reactivation problems

src/modules/stream/stream.h

@@ -15,6 +15,7 @@ private:
 	VoxelLodTerrain *terrain;
 	Node *current_scene;
 	ConfigFile config;
+	/* Per-building information */
 	struct building {
 		String id;
 		int pattern_id;
@@ -29,6 +30,7 @@ private:
 				      const String &key);
 		Dictionary to_dict() const;
 	};
+	/* Scene objects data */
 	struct scene_data {
 		Ref<PackedScene> packed_scene;
 		String path;
@@ -46,11 +48,20 @@ private:
 	};
 	using tile_map_t = std::unordered_map<const tile_key_t,
 					      std::vector<int>, tile_hash>;
+	/* Data for each building type */
 	HashMap<String, String> building_data;
+	/* Data for each building in a world */
 	std::vector<struct building> buildings;
 	Vector3 eye;
 	tile_map_t tiles;
 	tile_map_t loaded_tiles;
+	struct checkpoint_data {
+		HashMap<String, String> building_data;
+		std::vector<struct building> buildings;
+	};
+	std::vector<struct checkpoint_data> undo_log;
+	int undo_log_size;
+
 	int world_extent;
 	int tile_size;
 	int view_distance;
@@ -69,6 +80,8 @@ private:
 	void unload_building(int id);
 	void request_item(int type, int item);
 	void update_items();
+	void checkpoint();
+	void undo();
 
 	static void _bind_methods();