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diff --git a/hw6/src/boundedVolumeNode.cpp b/hw6/src/boundedVolumeNode.cpp
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+/******************************************************************/
+/* This file is part of the homework assignments for CSCI-427/527 */
+/* at The College of William & Mary and authored by Pieter Peers. */
+/* No part of this file, whether altered or in original form, can */
+/* be distributed or used outside the context of CSCI-427/527     */
+/* without consent of either the College of William & Mary or     */
+/* Pieter Peers.                                                  */
+/******************************************************************/
+#include <cassert>
+#include <algorithm>
+
+#include "boundedVolumeNode.h"
+#include "random_number.h"
+
+boundedVolumeNode::boundedVolumeNode(const std::vector<std::shared_ptr<const boundedPrimitive>>::iterator& start, const std::vector<std::shared_ptr<const boundedPrimitive>>::iterator& end)
+
+  : _left(nullptr), _right(nullptr), boundedPrimitive()
+{
+  assert(std::distance(start, end) > 1);
+
+  // compute the bounding box
+  for_each(start, end, [&](const std::shared_ptr<const boundedPrimitive>& prim)
+  {
+    _bb += prim->boundingbox();
+  });
+
+  // select random splitting dimension & pivot
+  unsigned int split = random_int(2);
+  float pivot  = _bb.center()[split];
+
+  // partition
+  auto middle = std::partition(start, end, [&](const std::shared_ptr<const boundedPrimitive>& prim)
+  {
+    return prim->boundingbox().center()[split] < pivot;
+  });
+
+  // special case: all centers are the same.
+  if(start == middle) middle++;
+
+  // create _left (recurse if more than one primitive)
+  if(std::distance(start, middle) == 1)
+    _left = *start;
+  else 
+    _left = std::shared_ptr<const boundedPrimitive>(new boundedVolumeNode(start, middle));
+
+  // create _right (recurse if more than one primitive)
+  if(std::distance(middle, end) == 1)
+    _right = *middle;
+  else 
+    _right = std::shared_ptr<const boundedPrimitive>(new boundedVolumeNode(middle, end));
+
+  // Done.
+}
+
+intersectionPoint boundedVolumeNode::intersect(const ray& r) const
+{
+  intersectionPoint leftIp, rightIp;
+
+  // check left child
+  if(_left && _left->hitBoundingBox(r))
+    leftIp = _left->intersect(r);
+
+  // check right child
+  if(_right && _right->hitBoundingBox(r))
+    rightIp = _right->intersect(r);
+
+  // return closest
+  return std::min(leftIp, rightIp);
+}
+
+
+float boundedVolumeNode::area(void) const
+{
+  float total_area = 0.0f;
+  if(_left) total_area += _left->area();
+  if(_right) total_area += _right->area();
+  return total_area;
+}
+
+
+surfaceSample boundedVolumeNode::sample(float r1, float r2) const
+{
+  if(_left && !_right) return _left->sample(r1, r2);
+  else if(_right && !_left) return _right->sample(r1, r2);
+  else
+  {
+    float area_left = _left->area();
+    float area_right = _right->area();
+    float prob_left = area_left / (area_left + area_right);
+    float prob_right = 1.0f - prob_left;
+
+    if(r1 <= prob_left)
+      return _left->sample(r1 / prob_left, r2) * prob_left;
+    else
+      return _right->sample((r1 - prob_left) / prob_right, r2) * prob_right;
+  }
+}