Function Sort

Rendering/Volume/vtkBlockSortHelper.h:278–382

template <class RandomIt, typename T>
inline void Sort(RandomIt bitr, RandomIt eitr, BackToFront<T>& me)
{
  auto start = bitr;

  // brute force for testing

  std::vector<typename RandomIt::value_type> working;
  std::vector<typename RandomIt::value_type> result;
  working.assign(bitr, eitr);
  size_t numNodes = working.size();

#ifdef MB_DEBUG
  // check for any short loops and debug
  for (auto it = working.begin(); it != working.end(); ++it)
  {
    auto it2 = it;
    it2++;
    for (; it2 != working.end(); ++it2)
    {
      int comp1 = me.CompareOrderWithUncertainty(*it, *it2);
      int comp2 = me.CompareOrderWithUncertainty(*it2, *it);
      if (comp1 * comp2 > 0)
      {
        me.CompareOrderWithUncertainty(*it, *it2);
        me.CompareOrderWithUncertainty(*it2, *it);
      }
    }
  }

  // build the graph
  std::vector<gnode<RandomIt>> graph;
  for (auto it = working.begin(); it != working.end(); ++it)
  {
    gnode<RandomIt> anode;
    anode.Value = it;
    graph.push_back(anode);
  }
  for (auto& git : graph)
  {
    for (auto& next : graph)
    {
      if (git.Value != next.Value && me.CompareOrderWithUncertainty(*git.Value, *next.Value) > 0)
      {
        git.Closer.push_back(&next);
      }
    }
  }

  // graph constructed, now look for a loop
  std::vector<gnode<RandomIt>> active;
  std::vector<gnode<RandomIt>> loop;
  for (auto& gval : graph)
  {
    loop.clear();
    if (findCycle(gval, graph, active, loop))
    {
      vtkVector3d dir = me.CameraViewDirection;
      dir.Normalize();