[vtkusers] Question About selecting a point in vtkCanvas -- Java.

[satyanarayana reddy]

Hi Seb,
        I have a 3D box with the dimensions (0 200,0 200, 0 200) rendered
through a class inherited from vtkCanvas. My requirement is to pick a point
from the mouse click and display a sphere at that point. I am checking
about the vtkPointPicker.
And I am using the following code to pick the point.  It is not giving the
correct position.  Is there any mistake in what I am doing.

@Override
public void mousePressed(MouseEvent e)
    {
        vtkPointPicker picker = new vtkPointPicker();
        picker.SetTolerance(0.01);
        int result = picker.Pick(e.getX(), e.getY(), 0.0,
this.GetRenderer());

        double[] pick;
        if(result!=0)
            pick = picker.GetPickPosition();

        System.out.println(pick[0] + " " + pick[1]+ " " + pick[2]);
        sphereActor.SetPosition(pick[0],pick[1],pick[2]);
        this.GetRenderer().AddActor(sphereActor);
}

Thanks for your time

-Satya.

On Mon, Jun 11, 2012 at 1:16 PM, Sebastien Jourdain <
sebastien.jourdain at kitware.com> wrote:

> I don't know what should be the Z value, but I guess that depend what
> you try to achieve.
>
> Seb
>
> On Mon, Jun 11, 2012 at 11:58 AM, satyanarayana reddy
> <satyajanga at gmail.com> wrote:
> > Hi Seb,
> >        Thank you for the reply. what should be the value of Z?
> >
> > -Satya.
> >
> >
> > On Mon, Jun 11, 2012 at 11:56 AM, Sebastien Jourdain
> > <sebastien.jourdain at kitware.com> wrote:
> >>
> >> I guess it's because you said that the point is at z=0 so the z will
> >> still be wrong after your convert ion. On the other hand, point and
> >> cell picker do work in Java as I remember doing it a while ago.
> >> By default its the "p" key that you need to hit to trigger the
> picking...
> >>
> >> On Mon, Jun 11, 2012 at 11:36 AM, satyanarayana reddy
> >> <satyajanga at gmail.com> wrote:
> >> >
> >> >
> >> > Dear vtkusers,
> >> >             I have a requirement in which I need to select a point( by
> >> > mouse
> >> > click) in Cube. I am not using vtkPointPicker/vtkCellPicker as they
> does
> >> > not
> >> > seem to compatible in Java.
> >> >   I am creating a class which extends vtkCanvas to render the cube
> and I
> >> > am
> >> > overriding the mouse listeners in vtkCanvas  to pick the event
> position
> >> > and
> >> > converting it to World Coordinates using the following code as I am
> not
> >> > sure
> >> > how to use the static methods in vtkInteractorObserver(in Java wrapped
> >> > vtk),
> >> >
> >> >     double[] GetDisplayToWorldCoordinates(double x, double y)
> >> >     {
> >> > /* x,y represent the event position*/
> >> >         double[] coordinates = new double[3];
> >> >         coordinates[0]=(double)x;
> >> >         coordinates[1]=(double)y;
> >> >         coordinates[2]=0;
> >> >         double[] worldCord = new double[3];
> >> >
> >> >         this.GetRenderer().SetDisplayPoint(coordinates);
> >> >         this.GetRenderer().DisplayToView();
> >> >         this.GetRenderer().ViewToWorld();
> >> >         worldCord=    this.GetRenderer().GetWorldPoint();
> >> >
> >> >        return worldCord;
> >> >    }
> >> >
> >> >
> >> > My box source is (0,200,0,200,0,200). But the worldCord returned from
> >> > the
> >> > function is not what I expected. They are not even coming in the
> >> > extent.
> >> >
> >> > Please check If I am doing anything wrong. Or suggest how to convert
> the
> >> > event position in object coordinate system.
> >> >
> >> >
> >> > Thanks in advance,
> >> >
> >> > Best Regards,
> >> > Satya.
> >> >
> >> >
> >> >
> >> >
> >
> >
>
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