[vtkusers] Problems with vtkPanel (Java) under Windows

[Christopher Auer]

Hello!

We are currently doing our thesis about an application using VTK under
Java. We are usually displaying more than one vtkPanel on a Frame (but
the problem I am going to describe here also raises its head with only
one vtkPanel in use). For our GUI we are using the SWT
(http://www.eclipse.org) which is a Java library with bindings to the
native GUI library (via a DLL/.so for MFC/GTK+/Motif etc.). Under SWT
there is a SWT-AWT bridge to display AWT/Swing components under SWT -
this usually works very fine and seems not to be the root of the problem
(the problem does also occur with pure AWT application). We are using
Java 1.5.

But to shorten the story, here is my problem: When I start up the
application everything is working fine. All the vtkPanels behave the way
they should do (rotating and other user interactions work). I am
currently just displaying the surface of the objects - so nothing
special. In my application the user is able to change the displayed
object (e.g. Sphere -> Plane). So what I do is to remove the old actor
(e.g. Sphere) from the scene and then add the new actor (e.g. Plane).
But after that the vtkPanel does not react anymore. Instead the
vtkOutputWindow raises, with always the same error message:

ERROR: In C:\VTK\Rendering\vtkWin32OpenGLRenderWindow.cxx ...
...wglMakeCurrent... 

The rest of the error message is hidden and I cannot resize the
vtkOutputWindow. But I know that the error message has something to do
we already used resources or something like that.

To me it seems that there are several concurrent accesses to the
vtkPanel object, but I am running out of ideas (and time!).

What I've tried so far:

* created my own vtkPanel which derives from vtkPanel provides its own
removeActor/addActor-method with Lock()/UnLock()-calls wrapped around
the actual Remove/AddActor-calls (I tried also to use Lock/UnLock only
for the RemoveActor-method)
* I tried VTK4.2 and VTK4.4-latest-release (both with exactly the same
result)
* Created pure AWT-Frames

The only (impure) solution is to set the actors invisible instead of
removing them. But the errors also occurs after calling
vtkPanel.Render() to update the display after a change.

The searched the vtk mailinglists and the internet and tried the
solutions (see above). So my last hope is this mailinglist.

Has anyone an idea how to solve the problem?

Thanks in advance!



Christopher Auer
-- 
Christopher Auer <christopher.auer at web.de>