用VTK读取三维点云图并显示的程序遇到有关问题，求帮助(2)

  map1->SelectColorArray("colors");


   
  vtkActor *actor1 = vtkActor:: New();
  actor1->SetMapper(map1);
  actor1->GetProperty()->SetColor(0.2, 0.5, 0.75);

  vtkCamera *camera = vtkCamera::New();
  camera->SetPosition(5.0,0.0,0.0);
  camera->SetFocalPoint(-1.0,0.0,0.0);
  camera->SetViewUp(0.0,1.0,0.0);
  ren->SetActiveCamera(camera);

vtkRenderWindow *renWin = vtkRenderWindow::New();

  renWin->AddRenderer(ren);
  renWin->SetSize( 300, 300 );  
  vtkRenderWindowInteractor *iRen = vtkRenderWindowInteractor::New();
  iRen->SetRenderWindow(renWin);  
   
  ren->AddActor(actor1);
  ren->SetBackground(1, 1, 1);

   
  iRen->Initialize();
  iRen->Start();
  renWin->Render();
   

}


修改后的程序，调试时没有错误，但是执行时无法显示窗口，是哪里出了问题呢？有高手解答下吗？

------解决方案--------------------
把
vtkCamera *camera = vtkCamera::New();
camera->SetPosition(5.0,0.0,0.0);
camera->SetFocalPoint(-1.0,0.0,0.0);
camera->SetViewUp(0.0,1.0,0.0);
ren->SetActiveCamera(camera);
这段代码注释掉就可以了，为什么我也不知道，我也刚刚接触VTK。