Added a shape map to I3D class for quick lookup

I3DShapesTool.Lib/Model/I3D/I3D.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 
 namespace I3DShapesTool.Lib.Model.I3D
 {
@@ -7,5 +8,41 @@ public class I3D
         public string? Name { get; set; }
         public string? Version { get; set; }
         public TransformGroup SceneRoot { get; } = new TransformGroup("root", 0, I3DVector.Zero, I3DVector.Zero, I3DVector.One);
+
+        private IDictionary<int, Shape>? _shapesMap;
+
+        private void MapShapesRecurse(TransformGroup parent)
+        {
+            if (_shapesMap == null)
+                throw new InvalidOperationException();
+
+            if (parent is Shape shape && shape.ShapeId != null)
+            {
+                _shapesMap.Add((int)shape.ShapeId, shape);
+            }
+
+            foreach (var child in parent.Children)
+            {
+                MapShapesRecurse(child);
+            }
+        }
+
+        private void MapShapes()
+        {
+            _shapesMap = new Dictionary<int, Shape>();
+            MapShapesRecurse(SceneRoot);
+        }
+
+        public void Setup()
+        {
+            MapShapes();
+        }
+
+        public Shape? GetShape(int id)
+        {
+            if (_shapesMap == null || !_shapesMap.ContainsKey(id))
+                return null;
+            return _shapesMap[id];
+        }
     }
 }

I3DShapesTool.Lib/Model/I3D/I3DXMLReader.cs

@@ -130,6 +130,8 @@ public static I3D ParseXML(string filePath)
                 }
             }
 
+            result.Setup();
+
             return result;
         }
     }