Method BuildLocatorInternal

Common/DataModel/vtkOctreePointLocator.cxx:303–426

------------------------------------------------------------------------------

//------------------------------------------------------------------------------
void vtkOctreePointLocator::BuildLocatorInternal()
{
  if (!this->DataSet || this->DataSet->GetNumberOfPoints() == 0)
  {
    vtkErrorMacro("No data set");
    return;
  }

  int numPoints = this->GetDataSet()->GetNumberOfPoints();

  if (numPoints >= VTK_INT_MAX)
  {
    // When point IDs are stored in an "int" instead of a vtkIdType,
    // performance doubles.  So we store point IDs in an "int" during
    // the calculation.  This will need to be rewritten if true 64 bit
    // IDs are required.

    vtkErrorMacro("Intentional 64 bit error - time to rewrite code.");
    return;
  }

  vtkDebugMacro(<< "Creating octree");
  this->FreeSearchStructure();

  // Fix bounds - (1) push out a little if flat
  // (2) pull back the x, y and z lower bounds a little bit so that
  // points are clearly "inside" the spatial region.  Point p is
  // "inside" region r = [r1, r2] if r1 < p <= r2.

  double bounds[6], diff[3];

  this->GetDataSet()->GetBounds(bounds);

  this->MaxWidth = 0.0;
  int i;
  for (i = 0; i < 3; i++)
  {
    diff[i] = bounds[2 * i + 1] - bounds[2 * i];
    this->MaxWidth = static_cast<float>((diff[i] > this->MaxWidth) ? diff[i] : this->MaxWidth);
  }

  if (this->CreateCubicOctants)
  {
    // make the bounding box have equal length sides so that all octants
    // will also have equal length sides
    for (i = 0; i < 3; i++)
    {
      if (diff[i] != this->MaxWidth)
      {
        double delta = this->MaxWidth - diff[i];
        bounds[2 * i] -= .5 * delta;
        bounds[2 * i + 1] += .5 * delta;
        diff[i] = this->MaxWidth;
      }
    }
  }

  this->FudgeFactor = this->MaxWidth * 10e-6;