Rewrote surface grouping method to be iterative instead of tail-recursive. Fixes potential stack overflow issues when loading particularly large and complex maps.

Assets/Scripts/Support/BrushModel.cs

@@ -66,27 +66,34 @@ public class BrushModel
 
     private void GroupSurfaces(QNode node, QSurface[] surfaces, Dictionary<(IntPtr, int, QSurfaceFlags), List<QSurface>> surfaceGroups)
     {
-        if (node.contents < 0)  // Leaf node
-            return;
+        var nodeQueue = new Queue<QNode>();
+        nodeQueue.Enqueue(node);
 
-        for (int surfIdx = 0; surfIdx < node.numSurfaces; ++surfIdx)
+        while (nodeQueue.Count > 0)
         {
-            var surface = surfaces[node.firstSurface + surfIdx];
+            node = nodeQueue.Dequeue();
+            if (node.contents < 0)  // Leaf node
+                continue;
             
-            IntPtr texPtr = surface.TextureInfo.texture;
-            int lightNum = surface.lightmapTextureNum;
-            QSurfaceFlags flags = surface.flags;
-            var key = (texPtr, lightNum, flags);
+            for (int surfIdx = 0; surfIdx < node.numSurfaces; ++surfIdx)
+            {
+                var surface = surfaces[node.firstSurface + surfIdx];
 
-            if (!surfaceGroups.ContainsKey(key))
-                surfaceGroups[key] = new List<QSurface>();
+                IntPtr texPtr = surface.TextureInfo.texture;
+                int lightNum = surface.lightmapTextureNum;
+                QSurfaceFlags flags = surface.flags;
+                var key = (texPtr, lightNum, flags);
 
-            surfaceGroups[key].Add(surface);
-        }
+                if (!surfaceGroups.ContainsKey(key))
+                    surfaceGroups[key] = new List<QSurface>();
 
-        foreach (var childNode in node.Children)
-        {
-            GroupSurfaces(childNode, surfaces, surfaceGroups);
+                surfaceGroups[key].Add(surface);
+            }
+
+            foreach (var childNode in node.Children)
+            {
+                nodeQueue.Enqueue(childNode);
+            }
         }
     }