VGRoid support (#27659)

* Dungeon spawn support for grid spawns

* Recursive dungeons working

* Mask approach working

* zack

* More work

* Fix recursive dungeons

* Heap of work

* weh

* the cud

* rar

* Job

* weh

* weh

* weh

* Master merges

* orch

* weh

* vgroid most of the work

* Tweaks

* Tweaks

* weh

* do do do do do do

* Basic layout

* Ore spawning working

* Big breaking changes

* Mob gen working

* weh

* Finalising

* emo

* More finalising

* reverty

* Reduce distance

Content.Shared/Procedural/Dungeon.cs

@@ -1,8 +1,16 @@
 namespace Content.Shared.Procedural;
 
+/// <summary>
+/// Procedurally generated dungeon data.
+/// </summary>
 public sealed class Dungeon
 {
-    public readonly List<DungeonRoom> Rooms;
+    public static Dungeon Empty = new Dungeon();
+
+    private List<DungeonRoom> _rooms;
+    private HashSet<Vector2i> _allTiles = new();
+
+    public IReadOnlyList<DungeonRoom> Rooms => _rooms;
 
     /// <summary>
     /// Hashset of the tiles across all rooms.
@@ -17,18 +25,64 @@ public sealed class Dungeon
 
     public readonly HashSet<Vector2i> Entrances = new();
 
-    public Dungeon()
+    public IReadOnlySet<Vector2i> AllTiles => _allTiles;
+
+    public Dungeon() : this(new List<DungeonRoom>())
     {
-        Rooms = new List<DungeonRoom>();
     }
 
     public Dungeon(List<DungeonRoom> rooms)
     {
-        Rooms = rooms;
+        // This reftype is mine now.
+        _rooms = rooms;
 
-        foreach (var room in Rooms)
+        foreach (var room in _rooms)
         {
-            Entrances.UnionWith(room.Entrances);
+            InternalAddRoom(room);
         }
+
+        RefreshAllTiles();
+    }
+
+    public void RefreshAllTiles()
+    {
+        _allTiles.Clear();
+        _allTiles.UnionWith(RoomTiles);
+        _allTiles.UnionWith(RoomExteriorTiles);
+        _allTiles.UnionWith(CorridorTiles);
+        _allTiles.UnionWith(CorridorExteriorTiles);
+        _allTiles.UnionWith(Entrances);
+    }
+
+    public void Rebuild()
+    {
+        _allTiles.Clear();
+
+        RoomTiles.Clear();
+        RoomExteriorTiles.Clear();
+        Entrances.Clear();
+
+        foreach (var room in _rooms)
+        {
+            InternalAddRoom(room, false);
+        }
+
+        RefreshAllTiles();
+    }
+
+    public void AddRoom(DungeonRoom room)
+    {
+        _rooms.Add(room);
+        InternalAddRoom(room);
+    }
+
+    private void InternalAddRoom(DungeonRoom room, bool refreshAll = true)
+    {
+        Entrances.UnionWith(room.Entrances);
+        RoomTiles.UnionWith(room.Tiles);
+        RoomExteriorTiles.UnionWith(room.Exterior);
+
+        if (refreshAll)
+            RefreshAllTiles();
     }
 }