VTK绘制线段用vtkLine、vtkLineSource和vtkPolyLine的区别

vtkPolyLine时可以一次设置多个点再连接成一段：

vtkSmartPointer<vtkPolyLine> polyLine=
    vtkSmartPointer<vtkPolyLine>::New();
  polyLine->GetPointIds()->SetNumberOfIds(5);
  for(unsignedint i = 0; i< 5; i++)
    {
    polyLine->GetPointIds()->SetId(i,i);
    }

用vtkLine连接多点成线段时，一次只能连接两个点：

for(unsignedint i = 0; i< 3; i++)
    {
    vtkSmartPointer<vtkLine> line=
      vtkSmartPointer<vtkLine>::New();
    line->GetPointIds()->SetId(0,i);
    line->GetPointIds()->SetId(1,i+1);
    lines->InsertNextCell(line);
    }

用vtkLineSource时一次也只能指定两个点，也可以一次性指定多个点，根据点的插入顺序来连接成线段：

vtkSmartPointer<vtkLineSource> lineSource=
    vtkSmartPointer<vtkLineSource>::New();
  lineSource->SetPoint1(p0);
  lineSource->SetPoint2(p1);
  lineSource->Update();

vtkSmartPointer<vtkLineSource> lineSource =

        vtkSmartPointer<vtkLineSource>::New();

      //lineSource->SetPoint1(p0);

      //lineSource->SetPoint2(p1);

      double origin[3] = {0.0, 0.0, 0.0};

        double p0[3] = {1.0, 0.0, 0.0};

        double p1[3] = {0.0, 1.0, 0.0};

        double p2[3] = {0.0, 1.0, 2.0};

        double p3[3] = {1.0, 2.0, 3.0};

        // Create a vtkPoints object and store the points in it

        vtkSmartPointer<vtkPoints> points =

          vtkSmartPointer<vtkPoints>::New();

        points->InsertNextPoint(origin);

        points->InsertNextPoint(p0);

        points->InsertNextPoint(p1);

        points->InsertNextPoint(p2);

        points->InsertNextPoint(p3);

        lineSource->SetPoints(points);

      lineSource->Update();