VTK/Examples/Cxx/PolyData/CellLocator

#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkCellLocator.h>
 
int main(int, char *[])
{
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->Update();
 
  // Create the tree
  vtkSmartPointer<vtkCellLocator> cellLocator = 
    vtkSmartPointer<vtkCellLocator>::New();
  cellLocator->SetDataSet(sphereSource->GetOutput());
  cellLocator->BuildLocator();
 
  double testPoint[3] = {2.0, 0.0, 0.0};
 
  //Find the closest points to TestPoint
  double closestPoint[3];//the coordinates of the closest point will be returned here
  double closestPointDist2; //the squared distance to the closest point will be returned here
  vtkIdType cellId; //the cell id of the cell containing the closest point will be returned here
  int subId; //this is rarely used (in triangle strips only, I believe)
  cellLocator->FindClosestPoint(testPoint, closestPoint, cellId, subId, closestPointDist2);
 
  std::cout << "Coordinates of closest point: " << closestPoint[0] << " " << closestPoint[1] << " " << closestPoint[2] << std::endl;
  std::cout << "Squared distance to closest point: " << closestPointDist2 << std::endl;
  std::cout << "CellId: " << cellId << std::endl;
 
  return EXIT_SUCCESS;
}