Method FindClosestNPoints

Common/DataModel/vtkPointLocator.cxx:642–751

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//------------------------------------------------------------------------------
void vtkPointLocator::FindClosestNPoints(int N, const double x[3], vtkIdList* result)
{
  this->BuildLocator();
  if (this->HashTable == nullptr)
  {
    return;
  }
  int i, j;
  double dist2;
  double pt[3];
  int level;
  vtkIdType ptId, nids, cno;
  vtkIdList* ptIds;
  int ijk[3], *nei;
  vtkNeighborPoints buckets;

  // clear out the result
  result->Reset();

  //  Find bucket point is in.
  this->GetBucketIndices(x, ijk);

  // there are two steps, first a simple expanding wave of buckets until
  // we have enough points. Then a refinement to make sure we have the
  // N closest points.
  level = 0;
  double maxDistance = 0.0;
  int currentCount = 0;
  IdTuple* res = new IdTuple[N];

  this->GetBucketNeighbors(&buckets, ijk, this->Divisions, level);
  while (buckets.GetNumberOfNeighbors() && currentCount < N)
  {
    for (i = 0; i < buckets.GetNumberOfNeighbors(); i++)
    {
      nei = buckets.GetPoint(i);
      cno = nei[0] + nei[1] * this->XD + nei[2] * this->SliceSize;

      if ((ptIds = this->HashTable[cno]) != nullptr)
      {
        nids = ptIds->GetNumberOfIds();
        for (j = 0; j < nids; j++)
        {
          ptId = ptIds->GetId(j);
          this->DataSet->GetPoint(ptId, pt);
          dist2 = vtkMath::Distance2BetweenPoints(x, pt);
          if (currentCount < N)
          {
            res[currentCount].Dist2 = dist2;
            res[currentCount].PtId = ptId;
            maxDistance = std::max(dist2, maxDistance);
            currentCount++;
            if (currentCount == N)
            {
              std::sort(res, res + currentCount);
            }
          }
          else if (dist2 < maxDistance)