基本概念

vtkVolumePicker是vtkCellPicker的子类，增强的体数据光线投射拾取器。

示例演示

我们利用vtkVolumePicker对体数据进行拾取。

/********************************************************************** Copyright (c) Mr.Bin. All rights reserved. For more information visit: http://blog.csdn.net/webzhuce **********************************************************************/ #include <vtkRenderWindow.h> #include <vtkRenderer.h> #include <vtkRenderWindowInteractor.h> #include <vtkImageReader2.h> #include <vtkGPUVolumeRayCastMapper.h> #include <vtkColorTransferFunction.h> #include <vtkPiecewiseFunction.h> #include <vtkVolumeProperty.h> #include <vtkMarchingCubes.h> #include <vtkPolyDataNormals.h> #include <vtkStripper.h> #include <vtkCellLocator.h> #include <vtkPolyDataMapper.h> #include <vtkProperty.h> #include <vtkActor.h> #include <vtkLookupTable.h> #include <vtkImageMapToColors.h> #include <vtkImageActor.h> #include <vtkImageMapper3D.h> #include <vtkTransform.h> #include <vtkPlane.h> #include <vtkCamera.h> #include <vtkConeSource.h> #include <vtkDataSetMapper.h> #include <vtkVolumePicker.h> #include <vtkCommand.h> class vtkMyMouseCommand : public vtkCommand { public: static vtkMyMouseCommand *New() { return new vtkMyMouseCommand; } //A function to point an actor along a vector void PointCone(vtkActor *actor, double nx, double ny, double nz) { actor->SetOrientation(0.0, 0.0, 0.0); double n = std::sqrt(nx*nx + ny*ny + nz*nz); if (nx < 0.0) { actor->RotateWXYZ(180, 0, 1, 0); n = -n; } actor->RotateWXYZ(180, (nx + n)*0.5, ny*0.5, nz*0.5); } virtual void Execute(vtkObject *caller, unsigned long eventId, void *callData) { //renWin->HideCursor(); int x, y; iren->GetEventPosition(x, y); picker->Pick(x, y, 0, ren); double p[3]; picker->GetPickPosition(p); std::cout << p[0]<< " "<< p[1]<<" " << p[2]<<std::endl; double n[3]; picker->GetPickNormal(n); redCone->SetPosition(p[0], p[1], p[2]); PointCone(redCone, n[0], n[1], n[2]); greenCone->SetPosition(p[0], p[1], p[2]); PointCone(greenCone, -n[0], -n[1], -n[2]); iren->Render(); } vtkRenderWindow *renWin; vtkRenderer *ren; vtkRenderWindowInteractor *iren; vtkVolumePicker *picker; vtkActor *redCone; vtkActor *greenCone; }; int main(int, char *[]) { //renderer and interactor vtkNew<vtkRenderer> ren; vtkNew<vtkRenderWindow> renWin; renWin->AddRenderer(ren); vtkNew<vtkRenderWindowInteractor> iren; iren->SetRenderWindow(renWin); //read the volume vtkNew<vtkImageReader2> reader; reader->SetDataExtent(0, 63, 0, 63, 0, 92); reader->SetFileNameSliceOffset(1); reader->SetDataScalarTypeToUnsignedShort(); reader->SetDataByteOrderToLittleEndian(); reader->SetFilePrefix("H:/VTK/Build-VTK-8.2.0/ExternalData/Testing/Data/headsq/quarter"); reader->SetDataSpacing(3.2, 3.2, 1.5); //set up the volume rendering vtkNew<vtkGPUVolumeRayCastMapper> volumeMapper; volumeMapper->SetInputConnection(reader->GetOutputPort()); volumeMapper->CroppingOn(); double croppingRegionPlanes[6] = {0.0, 141.6, 0.0, 201.6, 0.0, 138.0}; volumeMapper->SetCroppingRegionPlanes(croppingRegionPlanes); vtkNew<vtkColorTransferFunction> volumeColor; volumeColor->AddRGBPoint(0, 0.0, 0.0, 0.0); volumeColor->AddRGBPoint(180, 0.3, 0.1, 0.2); volumeColor->AddRGBPoint(1000, 1.0, 0.7, 0.6); volumeColor->AddRGBPoint(2000, 1.0, 1.0, 0.9); vtkNew<vtkPiecewiseFunction> volumeScalarOpacity; volumeScalarOpacity->AddPoint(0, 0.0); volumeScalarOpacity->AddPoint(180, 0.0); volumeScalarOpacity->AddPoint(1000, 0.2); volumeScalarOpacity->AddPoint(2000, 0.8); vtkNew<vtkPiecewiseFunction> volumeGradientOpacity; volumeGradientOpacity->AddPoint(0, 0.0); volumeGradientOpacity->AddPoint(90, 0.5); volumeGradientOpacity->AddPoint(100, 1.0); vtkNew<vtkVolumeProperty> volumeProperty; volumeProperty->SetColor(volumeColor); volumeProperty->SetScalarOpacity(volumeScalarOpacity); volumeProperty->SetGradientOpacity(volumeGradientOpacity); volumeProperty->SetInterpolationTypeToLinear(); volumeProperty->ShadeOff(); volumeProperty->SetAmbient(0.6); volumeProperty->SetDiffuse(0.6); volumeProperty->SetSpecular(0.1); vtkNew<vtkVolume> volume; volume->SetMapper(volumeMapper); volume->SetProperty(volumeProperty); // Do the surface rendering vtkNew<vtkMarchingCubes> boneExtractor; boneExtractor->SetInputConnection(reader->GetOutputPort()); boneExtractor->SetValue(0, 1150); boneExtractor->Update(); vtkNew<vtkPolyDataNormals>boneNormals; boneNormals->SetInputConnection(boneExtractor->GetOutputPort()); boneNormals->SetFeatureAngle(60.0); vtkNew<vtkStripper> boneStripper; boneStripper->SetInputConnection(boneNormals->GetOutputPort()); vtkNew<vtkCellLocator> boneLocator; boneLocator->SetDataSet(boneExtractor->GetOutput()); boneLocator->LazyEvaluationOn(); vtkNew<vtkPolyDataMapper> boneMapper; boneMapper->SetInputConnection(boneStripper->GetOutputPort()); boneMapper->ScalarVisibilityOff(); vtkNew<vtkProperty> boneProperty; boneProperty->SetColor(1.0, 1.0, 0.9); vtkNew<vtkActor> bone; bone->SetMapper(boneMapper); bone->SetProperty(boneProperty); //Create an image actor vtkNew<vtkLookupTable> table; table->SetRange(0, 2000); table->SetRampToLinear(); table->SetValueRange(0, 1); table->SetHueRange(0, 0); table->SetSaturationRange(0, 0); vtkNew<vtkImageMapToColors> mapToColors; mapToColors->SetInputConnection(reader->GetOutputPort()); mapToColors->SetLookupTable(table); mapToColors->Update(); vtkNew<vtkImageActor> imageActor; imageActor->GetMapper()->SetInputConnection(mapToColors->GetOutputPort()); imageActor->SetDisplayExtent(32, 32, 0, 63, 0, 92); //make a transform and some clipping planes vtkNew<vtkTransform> transform; transform->RotateWXYZ(-20, 0.0, -0.7, 0.7); volume->SetUserTransform(transform); bone->SetUserTransform(transform); imageActor->SetUserTransform(transform); auto c = volume->GetCenter(); vtkNew<vtkPlane> volumeClip; volumeClip->SetNormal(0, 1, 0); volumeClip->SetOrigin(c[0], c[1], c[2]); vtkNew<vtkPlane> boneClip; boneClip->SetNormal(1, 0, 0); boneClip->SetOrigin(c[0], c[1], c[2]); volumeMapper->AddClippingPlane(volumeClip); boneMapper->AddClippingPlane(boneClip); ren->AddViewProp(volume); ren->AddViewProp(bone); ren->AddViewProp(imageActor); auto camera = ren->GetActiveCamera(); camera->SetFocalPoint(c[0], c[1], c[2]); camera->SetPosition(c[0] + 500, c[1] - 100, c[2] - 100); camera->SetViewUp(0, 0, -1); //the cone points along the - x axis vtkNew<vtkConeSource> coneSource; coneSource->CappingOn(); coneSource->SetHeight(12); coneSource->SetRadius(5); coneSource->SetResolution(31); coneSource->SetCenter(6, 0, 0); coneSource->SetDirection(-1, 0, 0); vtkNew<vtkDataSetMapper> coneMapper; coneMapper->SetInputConnection(coneSource->GetOutputPort()); vtkNew<vtkActor> redCone; redCone->PickableOff(); redCone->SetMapper(coneMapper); redCone->GetProperty()->SetColor(1, 0, 0); vtkNew<vtkActor> greenCone; greenCone->PickableOff(); greenCone->SetMapper(coneMapper); greenCone->GetProperty()->SetColor(0, 1, 0); //Add the two cones(or just one, if you want); ren->AddViewProp(redCone); ren->AddViewProp(greenCone); //the picker vtkNew<vtkVolumePicker> picker ; picker->SetTolerance(1e-6); picker->SetVolumeOpacityIsovalue(0.1); //locator is optional, but improves performance for large polydata picker->AddLocator(boneLocator); renWin->Render(); vtkNew<vtkMyMouseCommand> mouseCommand; mouseCommand->renWin = renWin; mouseCommand->ren= ren; mouseCommand->iren = iren; mouseCommand->picker = picker; mouseCommand->redCone = redCone; mouseCommand->greenCone = greenCone; iren->AddObserver(vtkCommand::MouseMoveEvent, mouseCommand); iren->Start(); return EXIT_SUCCESS; }

运行结果

红锥体和绿锥体尖头相交处即拾取位置

参考资料

VolumePicker