Some improvements on tile instancing.

scenes/HexTile3D.tscn

@@ -23,6 +23,7 @@ script = ExtResource( 1 )
 
 [node name="Mesh" type="MeshInstance" parent="." groups=["GameGeometry"]]
 transform = Transform( -4.37114e-08, 0, 1, 0, 1, 0, -1, 0, -4.37114e-08, 0, -2.5, 0 )
+visible = false
 mesh = ExtResource( 3 )
 material/0 = ExtResource( 2 )
 

scenes/TileInstanceManager.cs

@@ -1,15 +1,19 @@
+using System.Diagnostics;
 using System.Linq;
 using Godot;
 using Godot.Collections;
 
 public class TileInstanceManager : Spatial
 {
+    private readonly Array<SceneTileChunk> _sceneTileChunks = new();
+    private MultiMeshInstance _tileMultiMeshInstance;
+    private ImageTexture _viewTileTypeTexture;
+
+    private World _world;
+
     // other members
     [Export] public bool ShowHexTiles;
     [Export] public Vector2 ViewCenterPlaneCoord;
-    private World _world;
-    private readonly Array<SceneTileChunk> _sceneTileChunks = new();
-    private ImageTexture _viewTileTypeTexture;
 
     // ui elements
 
@@ -26,6 +30,9 @@ public class TileInstanceManager : Spatial
         _world = GetNode<World>(World);
 
         _world.Connect("OnTilesChanged", this, nameof(HandleWorldTileChange));
+
+        _tileMultiMeshInstance = (MultiMeshInstance)FindNode("TileMultiMeshInstance");
+        Debug.Assert(_tileMultiMeshInstance != null);
     }
 
 
@@ -35,7 +42,7 @@ public class TileInstanceManager : Spatial
 
     private SceneTileChunk CreateSceneTileChunk(Vector2 chunkIndex)
     {
-        var sceneTileChunk = new SceneTileChunk(chunkIndex);
+        var sceneTileChunk = new SceneTileChunk(chunkIndex, _tileMultiMeshInstance);
 
         foreach (var hexTile3D in sceneTileChunk.TileNodes)
         {
@@ -87,10 +94,10 @@ public class TileInstanceManager : Spatial
 
             sceneTileChunk.ChunkIndex = chunkIndex;
 
-            if (ShowHexTiles)
+//            if (ShowHexTiles)
-                foreach (var tile3D in sceneTileChunk.TileNodes)
+//                foreach (var tile3D in sceneTileChunk.TileNodes)
-                    tile3D.Transform = new Transform(Basis.Identity.Scaled(Vector3.One * 0.95f),
+//                    tile3D.Transform = new Transform(Basis.Identity.Scaled(Vector3.One * 0.95f),
-                        tile3D.Transform.origin);
+//                        tile3D.Transform.origin);
 
             _sceneTileChunks.Add(sceneTileChunk);
         }
@@ -119,14 +126,15 @@ public class TileInstanceManager : Spatial
 
     private class SceneTileChunk : Spatial
     {
-        private Vector2 _chunkIndex = Vector2.Inf;
-
         private readonly PackedScene _hexTile3DScene = GD.Load<PackedScene>("res://scenes/HexTile3D.tscn");
+        private readonly MultiMeshInstance _multiMeshInstance;
         private readonly HexGrid HexGrid = new();
+        private readonly Array<int> TileInstanceIndices = new();
 
         public readonly Array<HexTile3D> TileNodes = new();
+        private Vector2 _chunkIndex = Vector2.Inf;
 
-        public SceneTileChunk(Vector2 chunkIndex)
+        public SceneTileChunk(Vector2 chunkIndex, MultiMeshInstance multiMeshInstance)
         {
             var chunkSize = global::World.ChunkSize;
 
@@ -144,6 +152,18 @@ public class TileInstanceManager : Spatial
                 AddChild(tile3D);
             }
 
+            _multiMeshInstance = multiMeshInstance;
+
+            var chunkTileCount = global::World.ChunkSize * global::World.ChunkSize;
+
+            foreach (var i in Enumerable.Range(0, chunkTileCount))
+                TileInstanceIndices.Add(_multiMeshInstance.Multimesh.InstanceCount + i);
+
+            _multiMeshInstance.Multimesh.InstanceCount += chunkTileCount;
+            _multiMeshInstance.Multimesh.VisibleInstanceCount = _multiMeshInstance.Multimesh.InstanceCount;
+
+            GD.Print("VisibleInstanceCount = " + _multiMeshInstance.Multimesh.VisibleInstanceCount);
+            
             ChunkIndex = chunkIndex;
         }
 
@@ -158,6 +178,22 @@ public class TileInstanceManager : Spatial
                 chunkTransform.origin = new Vector3(chunkOriginPlaneCoord.x, 0, chunkOriginPlaneCoord.y);
                 Transform = chunkTransform;
                 _chunkIndex = value;
+
+                var tileOrientation = new Basis(Vector3.Up, 90f * Mathf.Pi / 180f);
+
+                GD.Print("Updating transforms for instances of chunk " + value);
+                
+                foreach (var i in Enumerable.Range(0, TileInstanceIndices.Count))
+                {
+                    var column = i % global::World.ChunkSize;
+                    var row = i / global::World.ChunkSize;
+
+                    var tilePlaneCoord =
+                        HexGrid.GetHexCenterFromOffset(new Vector2(column, row));
+                    _multiMeshInstance.Multimesh.SetInstanceTransform(TileInstanceIndices[i],
+                        new Transform(tileOrientation,
+                            chunkTransform.origin + new Vector3(tilePlaneCoord.x, 0, tilePlaneCoord.y)));
+                }
             }
         }
     }

scenes/World.cs

@@ -296,6 +296,7 @@ public class World : Spatial
         if (oldState != GenerationState.Done && State == GenerationState.Done)
         {
             UpdateWorldViewTexture();
+
             EmitSignal("OnTilesChanged", _removedChunkIndices.ToArray(), _addedChunkIndices.ToArray());
         }
     }