vtk 对polydata的bool运算

1.vtk可以对implicit data运算， 通常的polydata需要转化为implicit 进行运算。 

 经查，网上有vtkImplicitPolyData类可以将polydata转化。

2. 将这些polydata通过vtkImplicitPolyData过滤后 丢给vtkClipPolydata，作为clippolydata的裁剪函数让clippolydata做裁剪操作

3.clipdata还需要原始的polydata，丢给他。 

4.把裁剪结果丢给polydatamapper。

5.走流水线

完事。

 

上段关键代码： 

// 1.读进来一个牛的模型，丢到renderer里

vtkOBJReader *wavefront = vtkOBJReader::New();

wavefront->SetFileName("E:\\data\\Viewpoint\\cow.obj"); //我在windows平台

wavefront->Update();

vtkPolyDataMapper *cowMapper = vtkPolyDataMapper::New();

cowMapper->SetInput(wavefront->GetOutput());

vtkActor *cow = vtkActor::New();

cow->SetMapper(cowMapper);

ren->AddActor(cow);

 

//2. 创建一个圆柱体，先变换，再三角化（似乎是必须的！）

vtkCylinderSource *cylinderB = vtkCylinderSource::New();

cylinderB->SetRadius(0.2);

cylinderB->SetResolution(21);

cylinderB->CappingOn();

vtkTransform *trans = vtkTransform::New();

trans->Translate(5.1, 2.0, 0.0);

trans->Scale(0.5, 0.5, 0.5);

trans->RotateZ(90);

 

vtkTransformPolyDataFilter *tf = vtkTransformPolyDataFilter::New();

tf->SetInput(cylinderB->GetOutput());

tf->SetTransform(trans);

vtkTriangleFilter *triangle = vtkTriangleFilter::New();

triangle->SetInput(tf->GetOutput());

 

vtkPolyDataNormals *norm = vtkPolyDataNormals::New();

norm->SetInput(triangle->GetOutput());

 

vtkPolyDataMapper *CylinderBMapper = vtkPolyDataMapper::New();

CylinderBMapper->SetInput(norm->GetOutput());

 

// Append 

vtkAppendPolyData *append = vtkAppendPolyData::New(); 

append->AddInput(CylinderBMapper->GetInput());

vtkActor *CylinderBActor = vtkActor::New();

CylinderBActor->SetMapper( CylinderBMapper );

CylinderBActor->GetProperty()->SetColor(0,1,0);

 

        //3.将圆柱体转化为implicitpolydata 。

vtkImplicitPolyData *polyToImplicitDataB = vtkImplicitPolyData::New();

polyToImplicitDataB->SetTolerance(0.5);

polyToImplicitDataB->SetInput(append->GetOutput());

 

        //4.我要裁剪!

vtkClipPolyData *clipper = vtkClipPolyData::New();

clipper->SetInput((vtkPolyData *)cow->GetMapper()->GetInput());  //我要裁剪谁？牛是吧，拿来

clipper->SetClipFunction(polyToImplicitDataB);                                //你要裁剪不是要方程么？也拿来

clipper->InsideOutOff();

clipper->GenerateClipScalarsOn();

 

        //5.剪好了 走流水线去！

vtkPolyDataMapper *newmapper = vtkPolyDataMapper::New();

newmapper->SetInput(clipper->GetOutput());

cow->SetMapper(newmapper); 

ren->AddActor(CylinderBActor);

ren->GetActiveCamera()->Azimuth(50);

ren->ResetCamera();

 

        //done！

renWin->Render();

结果图：