Group surfaces based on texture and lightmap, while keeping them grouped inside each brush submodel

Assets/Scripts/Modules/BrushModel.cs

@@ -37,7 +37,46 @@ public class BrushModel
             modelGO.transform.SetParent(rootGameObject.transform);
 
             var headNode = subModels[modelIdx].GetHeadNode(model);
-            CreateNodeMeshes(headNode, surfaces, modelGO);
+
+            var surfaceGroups = new Dictionary<(string, int), List<QSurface>>();
+            GroupSurfaces(headNode, surfaces, surfaceGroups);
+
+            foreach (var group in surfaceGroups)
+            {
+                var key = group.Key;
+                var groupGO = new GameObject($"T{key.Item1}_L{key.Item2}");
+                groupGO.transform.SetParent(modelGO.transform);
+
+                for (int i = 0; i < group.Value.Count; ++i)
+                {
+                    CreateSurfaceMeshes(group.Value[i], $"{i}", groupGO);
+                }
+            }
+        }
+    }
+
+    private void GroupSurfaces(QNode node, QSurface[] surfaces, Dictionary<(string, int), List<QSurface>> surfaceGroups)
+    {
+        if (node.contents < 0)  // Leaf node
+            return;
+
+        for (int surfIdx = 0; surfIdx < node.numSurfaces; ++surfIdx)
+        {
+            var surface = surfaces[node.firstSurface + surfIdx];
+            
+            string texName = surface.TextureInfo.Texture.name;
+            int lightNum = surface.lightmapTextureNum;
+            var key = (texName, lightNum);
+
+            if (!surfaceGroups.ContainsKey(key))
+                surfaceGroups[key] = new List<QSurface>();
+            
+            surfaceGroups[key].Add(surface);
+        }
+
+        foreach (var childNode in node.Children)
+        {
+            GroupSurfaces(childNode, surfaces, surfaceGroups);
         }
     }
 
@@ -49,7 +88,11 @@ public class BrushModel
         var nodeGO = new GameObject("Node");
         nodeGO.transform.SetParent(parentGO.transform);
 
-        CreateSurfaceMeshes(node, surfaces, nodeGO);
+        for (int surfIdx = 0; surfIdx < node.numSurfaces; ++surfIdx)
+        {
+            var surface = surfaces[node.firstSurface + surfIdx];
+            CreateSurfaceMeshes(surface, $"{node.firstSurface + surfIdx}", nodeGO);
+        }
 
         foreach (var childNode in node.Children)
         {
@@ -57,48 +100,41 @@ public class BrushModel
         }
     }
 
-    private void CreateSurfaceMeshes(QNode node, QSurface[] surfaces, GameObject nodeGO)
+    private void CreateSurfaceMeshes(QSurface surface, string key, GameObject nodeGO)
     {
-        for (int surfIdx = 0; surfIdx < node.numSurfaces; ++surfIdx)
+        foreach (var polyVerts in surface.GetPolygons())
         {
-            var surface = surfaces[node.firstSurface + surfIdx];
+            tempVertices.Clear();
+            tempTextureUVs.Clear();
+            tempLightmapUVs.Clear();
+            tempIndices.Clear();
 
-            foreach (var polyVerts in surface.GetPolygons())
+            for (int vertIdx = 0; vertIdx < polyVerts.Length; ++vertIdx)
             {
-                tempVertices.Clear();
-                tempTextureUVs.Clear();
-                tempLightmapUVs.Clear();
-                tempIndices.Clear();
-
-                for (int vertIdx = 0; vertIdx < polyVerts.Length; ++vertIdx)
-                {
-                    tempVertices.Add(polyVerts[vertIdx].position.ToVector3().ToUnity());
-                    tempTextureUVs.Add(polyVerts[vertIdx].textureUV.ToVector2());
-                    tempLightmapUVs.Add(polyVerts[vertIdx].lightmapUV.ToVector2());
-                }
-
-                // Reconstruct triangle fan
-                for (ushort index = 2; index < polyVerts.Length; ++index)
-                {
-                    tempIndices.Add(0);
-                    tempIndices.Add((ushort) (index - 1));
-                    tempIndices.Add(index);
-                }
+                tempVertices.Add(polyVerts[vertIdx].position.ToVector3().ToUnity());
+                tempTextureUVs.Add(polyVerts[vertIdx].textureUV.ToVector2());
+                tempLightmapUVs.Add(polyVerts[vertIdx].lightmapUV.ToVector2());
+            }
 
-                Mesh mesh = new Mesh();
-                mesh.name = $"Surface_{node.firstSurface + surfIdx}";
-                mesh.SetVertices(tempVertices);
-                mesh.SetUVs(0, tempTextureUVs);
-                mesh.SetUVs(1, tempLightmapUVs);
-                mesh.SetIndices(tempIndices, MeshTopology.Triangles, 0);
-                mesh.RecalculateNormals();
-                mesh.UploadMeshData(true);
-                meshes.Add(mesh);
-                
-                CreateMeshObject(mesh, nodeGO);
+            // Reconstruct triangle fan
+            for (ushort index = 2; index < polyVerts.Length; ++index)
+            {
+                tempIndices.Add(0);
+                tempIndices.Add((ushort) (index - 1));
+                tempIndices.Add(index);
             }
 
-            var texNum = surface.TextureInfo.Texture.TextureNum;
+            Mesh mesh = new Mesh();
+            mesh.name = $"Surface_{key}";
+            mesh.SetVertices(tempVertices);
+            mesh.SetUVs(0, tempTextureUVs);
+            mesh.SetUVs(1, tempLightmapUVs);
+            mesh.SetIndices(tempIndices, MeshTopology.Triangles, 0);
+            mesh.RecalculateNormals();
+            mesh.UploadMeshData(true);
+            meshes.Add(mesh);
+            
+            CreateMeshObject(mesh, nodeGO);
         }
     }