[vtkusers] Use landmarks on PolyData

[Massinissa Bandou]

Hi everyone!!

I'm wondering if someone could help me with this code? I want to add a
visible landmarks on a polydata according to mouse position. I found a good
example *http://www.vtk.org/pipermail/vtkusers/2004-February/071696.html*
but I want a new landmark(sphere) appears every time when I press ''p''. 

I'm not familiar with callback functions and I have tried many ways to add a
new sphere at the picked points but it seems not working. I would appreciate
if someone could refer me to some documentation about callback functions.

#include "vtkActor.h"
#include "vtkCamera.h"
#include "vtkCellArray.h"
#include "vtkFloatArray.h"
#include "vtkPointData.h"
#include "vtkPoints.h"
#include "vtkPolyData.h"
#include "vtkPolyDataMapper.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"
#include "vtkCommand.h"
#include "vtkPointPicker.h"
#include "vtkSphereSource.h"
#include "vtkProperty.h"

#include <stdio.h>

class vtkMyCallback : public vtkCommand
{
public:
    vtkMyCallback::vtkMyCallback() { m_pvtkActorSelection = NULL; };
    static vtkMyCallback *New() { return new vtkMyCallback; }
    void Delete() { delete this; }
    void PrintSelf(ostream&, vtkIndent) { }
    void PrintTrailer(ostream&, vtkIndent) { }
    void PrintHeader(ostream&, vtkIndent) { }
    void CollectRevisions(ostream&) {}
    void SetSelectionActor(vtkActor* pvtkActorSelection) {
m_pvtkActorSelection = pvtkActorSelection; };

    virtual void Execute(vtkObject *caller, unsigned long, void*)
    {
        vtkRenderWindowInteractor *iren =
reinterpret_cast<vtkRenderWindowInteractor*>(caller);
        vtkPointPicker *picker = (vtkPointPicker *)iren->GetPicker();
        cout << "PointId: " << picker->GetPointId() << "\n";
        if (picker->GetPointId() != -1)
        {
            if (m_pvtkActorSelection)
               
m_pvtkActorSelection->SetPosition(picker->GetPickPosition());
            iren->Render();
        }
    }
private:
    vtkActor* m_pvtkActorSelection;
};

int main( int argc, char *argv[] )
{
    int i;
    static float x[8][3]={{0,0,0}, {1,0,0}, {1,1,0}, {0,1,0},
        {0,0,1}, {1,0,1}, {1,1,1}, {0,1,1}};
    static vtkIdType pts[6][4]={{0,1,2,3}, {4,5,6,7}, {0,1,5,4},
        {1,2,6,5}, {2,3,7,6}, {3,0,4,7}};

    // We'll create the building blocks of polydata including data
attributes.
    vtkPolyData *cube = vtkPolyData::New();
    vtkPoints *points = vtkPoints::New();
    vtkCellArray *polys = vtkCellArray::New();
    vtkFloatArray *scalars = vtkFloatArray::New();

    // Load the point, cell, and data attributes.
    for (i=0; i<8; i++) points->InsertPoint(i,x[i]);
    for (i=0; i<6; i++) polys->InsertNextCell(4,pts[i]);
    for (i=0; i<8; i++) scalars->InsertTuple1(i,i);

    // We now assign the pieces to the vtkPolyData.
    cube->SetPoints(points);
    cube->SetPolys(polys);
    cube->GetPointData()->SetScalars(scalars);

    // Now we'll look at it.
    vtkPolyDataMapper *cubeMapper = vtkPolyDataMapper::New();
    cubeMapper->SetInput(cube);
    cubeMapper->SetScalarRange(0,7);
    vtkActor *cubeActor = vtkActor::New();
    cubeActor->SetMapper(cubeMapper);

    // The usual rendering stuff.
    vtkCamera *camera = vtkCamera::New();
    camera->SetPosition(1,1,1);
    camera->SetFocalPoint(0,0,0);

    vtkRenderer *renderer = vtkRenderer::New();
    vtkRenderWindow *renWin = vtkRenderWindow::New();
    renWin->AddRenderer(renderer);

    vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
    iren->SetRenderWindow(renWin);

    renderer->AddActor(cubeActor);
    renderer->SetActiveCamera(camera);
    renderer->ResetCamera();
    renderer->SetBackground(1,1,1);

    renWin->SetSize(300,300);

    // create marker for pick
    vtkSphereSource *sphere = vtkSphereSource::New();
    sphere->SetThetaResolution(8); sphere->SetPhiResolution(8);
    sphere->SetRadius(0.1);
    vtkPolyDataMapper *sphereMapper = vtkPolyDataMapper::New();
    sphereMapper->SetInput(sphere->GetOutput());
    vtkActor *sphereActor = vtkActor::New();
    sphereActor->SetMapper(sphereMapper);
    sphereActor->GetProperty()->SetColor(1,0,0);
    sphereActor->PickableOff();

    renderer->AddActor(sphereActor);

    // start renderer
    renWin->Render();

    // init picker
    vtkPointPicker *picker = vtkPointPicker::New();
    picker->SetTolerance(0.01);
    iren->SetPicker(picker);

    // init callback
    vtkMyCallback *callback = vtkMyCallback::New();
    callback->SetSelectionActor(sphereActor);
    iren->AddObserver(vtkCommand::EndPickEvent, callback);

    // start interaction
    iren->Start();

    // Clean up
    cube->Delete();
    points->Delete();
    polys->Delete();
    scalars->Delete();
    cubeMapper->Delete();
    cubeActor->Delete();
    camera->Delete();
    sphere->Delete();
    sphereMapper->Delete();
    sphereActor->Delete();
    picker->Delete();
    callback->Delete();
    renderer->Delete();
    renWin->Delete();
    iren->Delete();

    return 0;
}


thank you for your help!

Massi



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