WorldPointPicker
VTKExamples/Cxx/Interaction/WorldPointPicker
Description
This example demonstrates how to get the position of the point in 3D that is exactly behind the mouse click. This point is not likely a point that exists in the data set - i.e. it can be a point on the interior of a cell.
Code
WorldPointPicker.cxx
#include <vtkSmartPointer.h>
#include <vtkRendererCollection.h>
#include <vtkWorldPointPicker.h>
#include <vtkSphereSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkActor.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkObjectFactory.h>
// Define interaction style
class MouseInteractorStyle : public vtkInteractorStyleTrackballCamera
{
public:
static MouseInteractorStyle* New();
vtkTypeMacro(MouseInteractorStyle, vtkInteractorStyleTrackballCamera);
virtual void OnLeftButtonDown()
{
std::cout << "Picking pixel: " << this->Interactor->GetEventPosition()[0] << " " << this->Interactor->GetEventPosition()[1] << std::endl;
this->Interactor->GetPicker()->Pick(this->Interactor->GetEventPosition()[0],
this->Interactor->GetEventPosition()[1],
0, // always zero.
this->Interactor->GetRenderWindow()->GetRenderers()->GetFirstRenderer());
double picked[3];
this->Interactor->GetPicker()->GetPickPosition(picked);
std::cout << "Picked value: " << picked[0] << " " << picked[1] << " " << picked[2] << std::endl;
// Forward events
vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
}
};
vtkStandardNewMacro(MouseInteractorStyle);
int main(int, char *[])
{
vtkSmartPointer<vtkSphereSource> sphereSource =
vtkSmartPointer<vtkSphereSource>::New();
sphereSource->Update();
vtkSmartPointer<vtkWorldPointPicker> worldPointPicker =
vtkSmartPointer<vtkWorldPointPicker>::New();
// Create a mapper and actor
vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputConnection(sphereSource->GetOutputPort());
vtkSmartPointer<vtkActor> actor =
vtkSmartPointer<vtkActor>::New();
actor->SetMapper(mapper);
// 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->SetPicker(worldPointPicker);
renderWindowInteractor->SetRenderWindow(renderWindow);
vtkSmartPointer<MouseInteractorStyle> style =
vtkSmartPointer<MouseInteractorStyle>::New();
renderWindowInteractor->SetInteractorStyle( style );
// Add the actor to the scene
renderer->AddActor(actor);
renderer->SetBackground(1,1,1); // Background color white
// Render and interact
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(WorldPointPicker)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(WorldPointPicker MACOSX_BUNDLE WorldPointPicker.cxx)
target_link_libraries(WorldPointPicker ${VTK_LIBRARIES})
Download and Build WorldPointPicker
Click here to download WorldPointPicker and its CMakeLists.txt file. Once the tarball WorldPointPicker.tar has been downloaded and extracted,
cd WorldPointPicker/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./WorldPointPicker
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.