[vtkusers] Setting new Camera Position under Java

[Christian Pöcher]

Hello,

I am looking for help on setting new camera positions. I am developing under
VTK 3.2 and Sun JDK 1.2.2 on a Win2K machine.
I studied some examlpes in TCL on this fine discussion board and
re-implemented them, which worked as expected. I did:
...get the camera
    cam = ren.GetActiveCamera();
...set it to an new position and changed the focal point
    cam.SetPosition(3.0,3.0,3.0);
    cam.SetFocalPoint(0.0,0.0,0.0);
    cam.ComputeViewPlaneNormal();
...set a view-up-vector
   cam.OrthogonalizeViewUp();
...got the only light in the scenery
    lights = ren.GetLights();
    lights.InitTraversal();
    light = lights.GetNextItem();
...and set it to camera's position and focal point
    light.SetPosition(cam.GetPosition());
    light.SetFocalPoint(cam.GetFocalPoint());
...then I reset the clipping range
    ren.ResetCameraClippingRange();

The problem is that the visuals don't update, altough the coordinates are
set right (I checked it with a System.out.println(...);). Adding a
ren.Render(); changed nothing. But if I did just a little mouse dragging in
the vtkPanel
it updated correctly. That is why I thought of creating a MouseDragged event
by code. But doing so the new camera position was taken only after two or
three clicks
on the button, which triggered the code stated above. Sometimes I also seem
to be "lost
in space", because every rotation or ren.ResetCamera(); doesn't bring me
back to my
geometry.

It is essential for me to see the change after moving to a new camera
position, but a
"sometimes it works and sometimes not" way is even worse, so if you could
help me
figure out what's wrong, I'd really appriciate.

Chris