VTK鼠標選點

打開點雲後用鼠標選點並輸出選中點信息：

#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkRendererCollection.h>
#include <vtkDataSetMapper.h>
#include <vtkUnstructuredGrid.h>
#include <vtkIdTypeArray.h>
#include <vtkTriangleFilter.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkCommand.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkPoints.h>
#include <vtkCellArray.h>
#include <vtkPlaneSource.h>
#include <vtkCellPicker.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkProperty.h>
#include <vtkSelectionNode.h>
#include <vtkSelection.h>
#include <vtkExtractSelection.h>
#include <vtkObjectFactory.h>
#include <vtkPointSource.h>
#include <vtkDoubleArray.h>
#include <vtkPoints.h>
#include <vtkPointData.h>
//#include "vtkHeadFile.h"

// Catch mouse events
class MouseInteractorStyle : public vtkInteractorStyleTrackballCamera
{
public:
	static MouseInteractorStyle* New();

	MouseInteractorStyle()
	{
		selectedMapper = vtkSmartPointer<vtkDataSetMapper>::New();
		selectedActor = vtkSmartPointer<vtkActor>::New();
	}

	virtual void OnLeftButtonDown()
	{
		// Get the location of the click (in window coordinates)
		int* pos = this->GetInteractor()->GetEventPosition();

		vtkSmartPointer<vtkCellPicker> picker =
			vtkSmartPointer<vtkCellPicker>::New();
		picker->SetTolerance(/*0.0005*/ 0.001);

		// Pick from this location.
		picker->Pick(pos[0], pos[1], 0, this->GetDefaultRenderer());

		double* worldPosition = picker->GetPickPosition();
		std::cout << "Cell id is: " << picker->GetCellId() << std::endl;

		if(picker->GetCellId() != -1)
		{

			std::cout << "Pick position is: " << worldPosition[0] << " " << worldPosition[1]
			<< " " << worldPosition[2] << endl;

			vtkSmartPointer<vtkIdTypeArray> ids =
				vtkSmartPointer<vtkIdTypeArray>::New();
			ids->SetNumberOfComponents(1);
			ids->InsertNextValue(picker->GetCellId());

			vtkSmartPointer<vtkSelectionNode> selectionNode =
				vtkSmartPointer<vtkSelectionNode>::New();
			selectionNode->SetFieldType(vtkSelectionNode::CELL);
			selectionNode->SetContentType(vtkSelectionNode::INDICES);
			selectionNode->SetSelectionList(ids);

			vtkSmartPointer<vtkSelection> selection =
				vtkSmartPointer<vtkSelection>::New();
			selection->AddNode(selectionNode);

			vtkSmartPointer<vtkExtractSelection> extractSelection =
				vtkSmartPointer<vtkExtractSelection>::New();
#if VTK_MAJOR_VERSION <= 5
			extractSelection->SetInput(0, this->Data);
			extractSelection->SetInput(1, selection);
#else
			extractSelection->SetInputData(0, this->Data);
			extractSelection->SetInputData(1, selection);
#endif
			extractSelection->Update();

			// In selection
			vtkSmartPointer<vtkUnstructuredGrid> selected =
				vtkSmartPointer<vtkUnstructuredGrid>::New();
			selected->ShallowCopy(extractSelection->GetOutput());

			std::cout << "There are " << selected->GetNumberOfPoints()
				<< " points in the selection." << std::endl;
			std::cout << "There are " << selected->GetNumberOfCells()
				<< " cells in the selection." << std::endl;


#if VTK_MAJOR_VERSION <= 5
			selectedMapper->SetInputConnection(
				selected->GetProducerPort());
#else
			selectedMapper->SetInputData(selected);
#endif

			selectedActor->SetMapper(selectedMapper);
			selectedActor->GetProperty()->EdgeVisibilityOn();
			selectedActor->GetProperty()->SetEdgeColor(1,0,0);
			selectedActor->GetProperty()->SetLineWidth(3);
			selectedActor->GetProperty()->SetPointSize(10);

			this->Interactor->GetRenderWindow()->GetRenderers()->GetFirstRenderer()->AddActor(selectedActor);

		}
		// Forward events
		vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
	}

	vtkSmartPointer<vtkPolyData> Data;
	vtkSmartPointer<vtkDataSetMapper> selectedMapper;
	vtkSmartPointer<vtkActor> selectedActor;

};

vtkStandardNewMacro(MouseInteractorStyle);

int main (int, char *[])
{
	vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();  
	vtkSmartPointer<vtkDoubleArray> scalar = vtkSmartPointer<vtkDoubleArray>::New();//用高程值（Z座標值）填充，用於顯示  

	//讀取文件，將點雲存儲在vtkPoints對象中，並用高程值作爲屬性信息存儲在vtkDoubleArray對象中  
	FILE * fRead;  
	fRead = fopen("d:\\03.txt","r");  
	double pt[3];  
	int n=0;  
	while (!feof(fRead))  
	{  
		fscanf(fRead,"%lf %lf %lf",pt,pt+1,pt+2);  
		points->InsertPoint(n,pt[0],pt[1],pt[2]);  
		scalar->InsertNextTuple1(pt[2]);  
		n++;  
	}  

	vtkSmartPointer<vtkCellArray> polyvertex = vtkSmartPointer<vtkCellArray>::New();//vtkCell的具體實現  
	polyvertex->SetNumberOfCells(n);//設置ID個數  

	int i = 0;  
	for(i=0;i<n;i++)//建立拓撲關係  
	{  
		vtkIdType Cell[1] = {i};  
		polyvertex->InsertNextCell(1,Cell);//第一個參數：cell由一個點組成；第二個參數：組成cell的pointID  
	}  

	vtkSmartPointer<vtkPolyData > grid = vtkSmartPointer<vtkPolyData>::New();  
	grid->SetPoints(points);  
	grid->SetVerts(polyvertex);//設置建立vertex的cell array  

	grid->GetPointData()->SetScalars(scalar);  

	double p[3];
	grid->GetPoint(384456,p);
	std::cout << "Point 384456"<< " : (" << p[0] << " " << p[1] << " " << p[2] << ")" << std::endl;



	vtkSmartPointer<vtkPolyDataMapper> mapper =
		vtkSmartPointer<vtkPolyDataMapper>::New();
	//mapper->SetInputConnection(planeSource->GetOutputPort());
	mapper->SetInput(grid);
	mapper->SetScalarRange(-2,20);

	vtkSmartPointer<vtkActor> actor =
		vtkSmartPointer<vtkActor>::New();
	actor->GetProperty()->SetColor(0,1,0); //green
	actor->SetMapper(mapper);

	vtkSmartPointer<vtkRenderer> renderer =
		vtkSmartPointer<vtkRenderer>::New();
	vtkSmartPointer<vtkRenderWindow> renderWindow =
		vtkSmartPointer<vtkRenderWindow>::New();
	renderWindow->AddRenderer(renderer);

	vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
		vtkSmartPointer<vtkRenderWindowInteractor>::New();
	renderWindowInteractor->SetRenderWindow(renderWindow);
	renderWindowInteractor->Initialize();

	// Set the custom stype to use for interaction.
	vtkSmartPointer<MouseInteractorStyle> style =
		vtkSmartPointer<MouseInteractorStyle>::New();
	style->SetDefaultRenderer(renderer);
	style->Data = grid;

	renderWindowInteractor->SetInteractorStyle(style);

	renderer->AddActor(actor);
	renderer->ResetCamera();

	renderer->SetBackground(0,0,0); // Black

	renderWindow->Render();
	renderWindowInteractor->Start();

	return EXIT_SUCCESS;
}