Method BuildTree

Common/ExecutionModel/vtkSimpleScalarTree.cxx:84–193

------------------------------------------------------------------------------ Construct the scalar tree from the dataset provided. Checks build times and modified time from input and reconstructs the tree if necessary.

// Construct the scalar tree from the dataset provided. Checks build times
// and modified time from input and reconstructs the tree if necessary.
void vtkSimpleScalarTree::BuildTree()
{
  vtkIdType cellId, i, j, numScalars;
  int level, offset, parentOffset, prod;
  vtkIdType numNodes, node, numLeafs, leaf, numParentLeafs;
  vtkCell* cell;
  vtkIdList* cellPts;
  vtkScalarRange<double>*tree, *parent;
  double* s;
  vtkDoubleArray* cellScalars;

  // Check input...see whether we have to rebuild
  //
  if (!this->DataSet || (this->NumCells = this->DataSet->GetNumberOfCells()) < 1)
  {
    vtkErrorMacro(<< "No data to build tree with");
    return;
  }

  if (this->Tree != nullptr && this->BuildTime > this->MTime &&
    this->BuildTime > this->DataSet->GetMTime())
  {
    return;
  }

  vtkDebugMacro(<< "Building scalar tree...");

  // If no scalars set then try and grab them from dataset
  if (!this->Scalars)
  {
    this->SetScalars(this->DataSet->GetPointData()->GetScalars());
  }
  if (!this->Scalars)
  {
    vtkErrorMacro(<< "No scalar data to build trees with");
    return;
  }

  this->Initialize();
  cellScalars = vtkDoubleArray::New();
  cellScalars->Allocate(100);

  // Compute the number of levels in the tree
  //
  numLeafs = static_cast<int>(ceil(static_cast<double>(this->NumCells) / this->BranchingFactor));
  for (prod = 1, numNodes = 1, this->Level = 0; prod < numLeafs && this->Level <= this->MaxLevel;
       this->Level++)
  {
    prod *= this->BranchingFactor;
    numNodes += prod;
  }

  this->LeafOffset = offset = numNodes - prod;
  vtkScalarRange<double>* TTree;
  this->TreeSize = numNodes - (prod - numLeafs);
  this->Tree = TTree = new vtkScalarRange<double>[this->TreeSize];
  for (i = 0; i < this->TreeSize; i++)
  {