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diff --git a/hw6/src/boundingBox.cpp b/hw6/src/boundingBox.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 "interval.h"
+#include "constants.h"
+#include "boundingBox.h"
+
+
+/////////////////
+// Constructor //
+/////////////////
+boundingBox::boundingBox(void)
+{
+  // create an empty box (i.e., 'left' lies right of 'right')
+  _lfb = vec3d(+LARGE);
+  _rbt = vec3d(-LARGE);
+}
+
+
+boundingBox::boundingBox(const vec3d& lfb, const vec3d& rbt)
+{
+  _lfb = lfb;
+  _rbt = rbt;
+
+  // Make sure each component in _lfb is smaller than _rbt
+  for(unsigned int i=0; i < vec3d::size(); i++)
+    if(_rbt[i] < _lfb[i]) std::swap(_rbt[i], _lfb[i]);
+
+  // Done.
+}
+
+
+boundingBox::boundingBox(const boundingBox& bb)
+{
+  _lfb = bb._lfb;
+  _rbt = bb._rbt;
+}
+
+
+//////////////
+// Operator //
+//////////////
+boundingBox& boundingBox::operator=(const boundingBox& src)
+{
+  _assign(src);
+  return *this;
+}
+  
+
+boundingBox& boundingBox::operator+=(const boundingBox& bb)
+{
+  // compute the union of two bounding boxes
+  for(unsigned int i=0; i < vec3d::size(); i++)
+  {
+    if(_lfb[i] > bb._lfb[i]) _lfb[i] = bb._lfb[i];
+    if(_rbt[i] < bb._rbt[i]) _rbt[i] = bb._rbt[i];
+  }
+
+  return *this;
+}
+
+
+boundingBox boundingBox::operator+(const boundingBox& bb) const
+{
+  boundingBox result(*this);
+  result += bb;
+  return result;
+}
+
+
+boundingBox& boundingBox::operator+=(const vec3d& point)
+{
+  // expand the bounding box to include 'point' (+ a small epsilon)
+  for(unsigned int i=0; i < vec3d::size(); i++)
+  {
+    if(_lfb[i] > point[i]-EPSILON) _lfb[i] = point[i]-EPSILON;
+    if(_rbt[i] < point[i]+EPSILON) _rbt[i] = point[i]+EPSILON;
+  }
+
+  return *this;
+}
+
+
+/////////////
+// Methods //
+/////////////
+bool boundingBox::isHit(const ray& r) const
+{
+  // init
+  interval boxInterval(0, +LARGE);
+
+  // for every slab
+  for(unsigned int i=0; i != vec3d::size(); i++)
+  {
+    // compute the slab
+    interval slab(_lfb[i], _rbt[i]);
+    slab -= r.origin()[i];
+
+    // check for the case where the ray is parallel to the slab
+    if(fabs(r.direction()[i]) < EPSILON)
+    {
+      // if identical signs => no hit
+      if((slab.lower() < 0.0f) == (slab.upper() < 0.0f))
+	return false;
+
+      // skip remainder to this iteration
+      continue;
+    }
+    else
+      slab /= r.direction()[i];
+
+    // intersect
+    boxInterval.intersect(slab);
+    if(boxInterval.empty())
+      return false;
+  }
+
+  // Done.
+  return true;  
+}
+
+
+vec3d boundingBox::center(void) const
+{
+  return 0.5f * (_lfb + _rbt);
+}
+
+
+vec3d boundingBox::corner(bool left, bool front, bool bottom) const
+{
+  return vec3d( left ? _lfb.x : _rbt.x,
+		front ? _lfb.y : _rbt.y,
+		bottom ? _lfb.z : _rbt.z );
+}
+
+
+vec3d boundingBox::size(void) const
+{
+  vec3d s = (_rbt - _lfb);
+  if(s.x < 0 || s.y < 0 || s.z < 0) return vec3d();
+  else return s;
+}
+
+
+//////////////
+// Mutators //
+//////////////
+boundingBox& boundingBox::transform(const transformation3d& t)
+{
+  boundingBox result;
+  for(unsigned int i=0; i <= 1; i++)
+    for(unsigned int j=0; j <= 1; j++)
+      for(unsigned int k=0; k <= 1; k++)
+	result += t.transformPoint(corner(i,j,k));
+
+  // Done.
+  _swap(result);
+  return *this;
+}
+
+
+boundingBox& boundingBox::inverseTransform(const transformation3d& t)
+{
+  boundingBox result;
+  for(unsigned int i=0; i <= 1; i++)
+    for(unsigned int j=0; j <= 1; j++)
+      for(unsigned int k=0; k <= 1; k++)
+	result += t.inverseTransformPoint(corner(i,j,k));
+
+  // Done.
+  _swap(result);
+  return *this;
+}
+
+/////////////////////
+// Private Methods //
+/////////////////////
+void boundingBox::_swap(boundingBox& bb)
+{
+  swap(_lfb, bb._lfb);
+  swap(_rbt, bb._rbt);
+}
+
+
+void boundingBox::_assign(const boundingBox& bb)
+{
+  _lfb = bb._lfb;
+  _rbt = bb._rbt;
+}