通过VTK显示STL模型_vtk中读取stl中得setlocator怎么用

void showStlModel(const std::string& modelPath){
    vtkSmartPointer<vtkSTLReader> stlReader = vtkSmartPointer<vtkSTLReader>::New();
    stlReader->SetFileName(modelPath.c_str());//modelPath是stl模型在电脑里面的存储路径
    stlReader->Update();
 
    if (!_cellLocator) {
        _cellLocator = vtkSmartPointer<vtkCellLocator>::New();
    }
    _cellLocator->SetDataSet(stlReader->GetOutput());
    _cellLocator->BuildLocator();
 
    if (!_stlModel) {
        _stlModel = vtkSmartPointer<vtkPolyData>::New();
    }
    _stlModel = stlReader->GetOutput();
    auto normals = vtkSmartPointer<vtkTriangleMeshPointNormals>::New();
    normals->SetInputData(_stlModel);
    normals->Update();
    _stlModel = normals->GetOutput();
    auto modelMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    _modelActor->SetMapper(modelMapper);
    modelMapper->SetInputConnection(stlReader->GetOutputPort());
    _qvtkWidget->GetRenderWindow()->Render();
}