VTK: vtkTubeFilter生成管道

                 vtkTubeFilter可以用来生成包围一条折线的管道。下面是一个vtkTubeFilter的使用例子。围绕一条线创建一个圆柱形管道。

         

#include <vtkSmartPointer.h>#include <vtkLine.h>#include <vtkCellArray.h>#include <vtkTubeFilter.h>#include <vtkLineSource.h>#include <vtkPolyData.h>#include <vtkPolyDataMapper.h>#include <vtkActor.h>#include <vtkRenderWindow.h>#include <vtkRenderer.h>#include <vtkRenderWindowInteractor.h>#include <vtkProperty.h>   int main(int, char *[]){  // Create a line  vtkSmartPointer<vtkLineSource> lineSource =     vtkSmartPointer<vtkLineSource>::New();  lineSource->SetPoint1(1.0, 0.0, 0.0);  lineSource->SetPoint2(0.0, 1.0, 0.0);   // Create a mapper and actor  vtkSmartPointer<vtkPolyDataMapper> lineMapper =     vtkSmartPointer<vtkPolyDataMapper>::New();  lineMapper->SetInputConnection(lineSource->GetOutputPort());  vtkSmartPointer<vtkActor> lineActor =     vtkSmartPointer<vtkActor>::New();  lineActor->GetProperty()->SetColor(0.0,0.0,0.1); // Give some color to the line  lineActor->SetMapper(lineMapper);   // Create a tube (cylinder) around the line  vtkSmartPointer<vtkTubeFilter> tubeFilter =     vtkSmartPointer<vtkTubeFilter>::New();  tubeFilter->SetInputConnection(lineSource->GetOutputPort());  tubeFilter->SetRadius(.025); //default is .5  tubeFilter->SetNumberOfSides(50);  tubeFilter->Update();   // Create a mapper and actor  vtkSmartPointer<vtkPolyDataMapper> tubeMapper =     vtkSmartPointer<vtkPolyDataMapper>::New();  tubeMapper->SetInputConnection(tubeFilter->GetOutputPort());  vtkSmartPointer<vtkActor> tubeActor =     vtkSmartPointer<vtkActor>::New();  tubeActor->GetProperty()->SetOpacity(0.5); //Make the tube have some transparency.  tubeActor->SetMapper(tubeMapper);   // Create a renderer, render window, and interactor  vtkSmartPointer<vtkRenderer> renderer =     vtkSmartPointer<vtkRenderer>::New();  vtkSmartPointer<vtkRenderWindow> renderWindow =     vtkSmartPointer<vtkRenderWindow>::New();  renderWindow->AddRenderer(renderer);  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =     vtkSmartPointer<vtkRenderWindowInteractor>::New();  renderWindowInteractor->SetRenderWindow(renderWindow);   // Add the actor to the scene  renderer->AddActor(tubeActor);  renderer->AddActor(lineActor);  renderer->SetBackground(0,1,0);   // Render and interact  renderWindow->Render();  renderWindowInteractor->Start();   return EXIT_SUCCESS;}

效果如下图：

   通过给折线上各点指定一个半径标量值，可以实现一个直径不断变化的管道。例子如下：

int main(int argc, char *argv[]){    vtkSmartPointer<vtkPoints> points =            vtkSmartPointer<vtkPoints>::New();    points->InsertPoint(0,1,0,0);    points->InsertPoint(1,2,0,0);    points->InsertPoint(2,3,1,0);    points->InsertPoint(3,4,1,0);    points->InsertPoint(4,5,0,0);    points->InsertPoint(5,6,0,0);    // Fit a spline to the points    vtkSmartPointer<vtkParametricSpline> spline =            vtkSmartPointer<vtkParametricSpline>::New();    spline->SetPoints(points);    vtkSmartPointer<vtkParametricFunctionSource> functionSource =            vtkSmartPointer<vtkParametricFunctionSource>::New();    functionSource->SetParametricFunction(spline);    functionSource->SetUResolution(10 * points->GetNumberOfPoints());    functionSource->Update();    // Interpolate the scalars    double rad;    vtkSmartPointer<vtkTupleInterpolator> interpolatedRadius =            vtkSmartPointer<vtkTupleInterpolator> ::New();    interpolatedRadius->SetInterpolationTypeToLinear();    interpolatedRadius->SetNumberOfComponents(1);    rad = .2; interpolatedRadius->AddTuple(0,&rad);    rad = .2; interpolatedRadius->AddTuple(1,&rad);    rad = .15; interpolatedRadius->AddTuple(2,&rad);    rad = .15; interpolatedRadius->AddTuple(3,&rad);    rad = .1; interpolatedRadius->AddTuple(4,&rad);    rad = .1; interpolatedRadius->AddTuple(5,&rad);    // Generate the radius scalars    vtkSmartPointer<vtkDoubleArray> tubeRadius =            vtkSmartPointer<vtkDoubleArray>::New();    unsigned int n = functionSource->GetOutput()->GetNumberOfPoints();    tubeRadius->SetNumberOfTuples(n);    tubeRadius->SetName("TubeRadius");    double tMin = interpolatedRadius->GetMinimumT(); std::cout << "tMin:" <<tMin;    double tMax = interpolatedRadius->GetMaximumT(); std::cout << "tMax:" <<tMax;    double r;    for (unsigned int i = 0; i < n; ++i)    {        double t = (tMax - tMin) / (n - 1) * i + tMin;        interpolatedRadius->InterpolateTuple(t, &r);        tubeRadius->SetTuple1(i, r);    }    // Add the scalars to the polydata    vtkSmartPointer<vtkPolyData> tubePolyData =            vtkSmartPointer<vtkPolyData>::New();    tubePolyData = functionSource->GetOutput();    tubePolyData->GetPointData()->AddArray(tubeRadius);    tubePolyData->GetPointData()->SetActiveScalars("TubeRadius");    // Create the tubes    vtkSmartPointer<vtkTubeFilter> tuber =            vtkSmartPointer<vtkTubeFilter>::New();#if VTK_MAJOR_VERSION <= 5    tuber->SetInput(tubePolyData);#else    tuber->SetInputData(tubePolyData);#endif    tuber->SetNumberOfSides(50);    tuber->SetVaryRadiusToVaryRadiusByAbsoluteScalar();    //--------------    // Setup actors and mappers    vtkSmartPointer<vtkPolyDataMapper> lineMapper =            vtkSmartPointer<vtkPolyDataMapper>::New();#if VTK_MAJOR_VERSION <= 5    lineMapper->SetInput(tubePolyData);#else    lineMapper->SetInputData(tubePolyData);#endif    lineMapper->SetScalarRange(tubePolyData->GetScalarRange());    vtkSmartPointer<vtkPolyDataMapper> tubeMapper =            vtkSmartPointer<vtkPolyDataMapper>::New();    tubeMapper->SetInputConnection(tuber->GetOutputPort());    tubeMapper->SetScalarRange(tubePolyData->GetScalarRange());    vtkSmartPointer<vtkActor> lineActor = vtkSmartPointer<vtkActor>::New();    lineActor->SetMapper(lineMapper);    vtkSmartPointer<vtkActor> tubeActor = vtkSmartPointer<vtkActor>::New();    tubeActor->SetMapper(tubeMapper);    tubeActor->GetProperty()->SetOpacity(0.3);    // Setup render window, renderer, and interactor    vtkSmartPointer<vtkRenderer> renderer =            vtkSmartPointer<vtkRenderer>::New();    vtkSmartPointer<vtkRenderWindow> renderWindow =            vtkSmartPointer<vtkRenderWindow>::New();    renderWindow->AddRenderer(renderer);    vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =            vtkSmartPointer<vtkRenderWindowInteractor>::New();    renderWindowInteractor->SetRenderWindow(renderWindow);    renderer->AddActor(lineActor);    renderer->AddActor(tubeActor);    renderer->SetBackground(.2, .3, .4);    renderWindow->Render();    renderWindowInteractor->Start();    return EXIT_SUCCESS;}