Picking
vtk-examples/Cxx/Interaction/Picking
Question
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Code¶
Picking.cxx
#include <vtkActor.h>
#include <vtkCellArray.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkObjectFactory.h>
#include <vtkPlaneSource.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkPropPicker.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkRendererCollection.h>
#include <vtkSphereSource.h>
namespace {
// Handle mouse events
class MouseInteractorStyle2 : public vtkInteractorStyleTrackballCamera
{
public:
static MouseInteractorStyle2* New();
vtkTypeMacro(MouseInteractorStyle2, vtkInteractorStyleTrackballCamera);
vtkNew<vtkNamedColors> colors;
virtual void OnLeftButtonDown() override
{
int* clickPos = this->GetInteractor()->GetEventPosition();
// Pick from this location.
vtkNew<vtkPropPicker> picker;
picker->Pick(clickPos[0], clickPos[1], 0, this->GetDefaultRenderer());
double* pos = picker->GetPickPosition();
std::cout << "Pick position (world coordinates) is: " << pos[0] << " "
<< pos[1] << " " << pos[2] << std::endl;
auto pickedActor = picker->GetActor();
if (pickedActor == nullptr)
{
std::cout << "No actor picked." << std::endl;
}
else
{
std::cout << "Picked actor: " << picker->GetActor() << std::endl;
// Create a sphere
// Create a sphere
vtkNew<vtkSphereSource> sphereSource;
sphereSource->SetCenter(pos[0], pos[1], pos[2]);
sphereSource->SetRadius(0.1);
// Create a mapper and actor
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(sphereSource->GetOutputPort());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("MistyRose").GetData());
this->GetDefaultRenderer()->AddActor(actor);
// Forward events
vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
}
}
private:
};
vtkStandardNewMacro(MouseInteractorStyle2);
} // namespace
// Execute application.
int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;
vtkNew<vtkPlaneSource> planeSource;
planeSource->Update();
// Create a polydata object
vtkPolyData* polydata = planeSource->GetOutput();
// Create a mapper
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputData(polydata);
// Create an actor
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(
colors->GetColor3d("LightGoldenrodYellow").GetData());
std::cout << "Actor address: " << actor << std::endl;
// A renderer and render window
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetWindowName("Picking");
// An interactor
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
// Set the custom stype to use for interaction.
vtkNew<MouseInteractorStyle2> style;
style->SetDefaultRenderer(renderer);
renderWindowInteractor->SetInteractorStyle(style);
// Add the actors to the scene
renderer->AddActor(actor);
renderer->SetBackground(colors->GetColor3d("DodgerBlue").GetData());
// Render and interact
renderWindow->Render();
renderWindowInteractor->Initialize();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(Picking)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkFiltersSources
vtkInteractionStyle
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
vtkRenderingOpenGL2
QUIET
)
if (NOT VTK_FOUND)
message("Skipping Picking: ${VTK_NOT_FOUND_MESSAGE}")
return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
# old system
include(${VTK_USE_FILE})
add_executable(Picking MACOSX_BUNDLE Picking.cxx )
target_link_libraries(Picking PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(Picking MACOSX_BUNDLE Picking.cxx )
target_link_libraries(Picking PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS Picking
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build Picking¶
Click here to download Picking and its CMakeLists.txt file. Once the tarball Picking.tar has been downloaded and extracted,
cd Picking/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:
./Picking
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.