/******************************************************************/
/* 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 "bvh_intersector.h"
#include "boundedVolumeNode.h"

//////////////////
// Constructors //
//////////////////
bvh_intersector::bvh_intersector(void)
  : intersector_base()
{
  // Do nothing
}


bvh_intersector::bvh_intersector(const std::vector<std::shared_ptr<const boundedPrimitive>>& compounds)
  : intersector_base()
{
  // quick bail out if no compounds provided
  if(compounds.empty()) return; 

  // make a copy
  std::vector<std::shared_ptr<const boundedPrimitive>> compoundCopy = compounds;

  // create node
  //   trivial case: only a single node
  if(compounds.size() == 1)
    _root = compounds[0];
  //   compound case: create a bvh
  else
    _root = std::shared_ptr<const boundedPrimitive>(new boundedVolumeNode(compoundCopy.begin(), compoundCopy.end()));
}

  
/////////////
// Methods //
/////////////
intersectionPoint bvh_intersector::intersect(const ray& r) const
{
  // check if BVH exists => empty intersection point if not.
  if(!_root) return intersectionPoint();

  // intersect
  return _root->intersect(r);
}