Merge pull request #1142 from SteelFill/light_hierarchy_correction

Fix Light Position Calculation for Deeper Hierarchy Levels

Author: twpol

Source/RunActivity/Viewer3D/Lights.cs

@@ -226,8 +226,29 @@ public void PrepareFrame(RenderFrame frame, ElapsedTime elapsedTime)
 
             // Calculate XNA matrix for shape file objects by offsetting from car's location
             // The new List<int> is intentional, this allows the dictionary to be changed while iterating
+            int maxDepth = trainCarShape.Hierarchy.Max();
             foreach (int index in new List<int>(ShapeXNATranslations.Keys))
-                ShapeXNATranslations[index] = trainCarShape.XNAMatrices[index] * xnaDTileTranslation;
+            {
+                Matrix res = trainCarShape.XNAMatrices[index];
+                int hIndex = trainCarShape.Hierarchy[index];
+
+                int i = 0;
+
+                // Transform the matrix repeatedly for all of its parents
+                while (hIndex > -1 && hIndex < trainCarShape.Hierarchy.Length && i < maxDepth)
+                {
+                    res = res * trainCarShape.XNAMatrices[hIndex];
+                    // Prevent potential infinite loop due to faulty hierarchy definition
+                    if (hIndex != trainCarShape.Hierarchy[hIndex])
+                        hIndex = trainCarShape.Hierarchy[hIndex];
+                    else
+                        break;
+
+                    i++;
+                }
+
+                ShapeXNATranslations[index] = res * xnaDTileTranslation;
+            }
 
             float objectRadius = 20; // Even more arbitrary.
             float objectViewingDistance = Viewer.Settings.ViewingDistance; // Arbitrary.