Still looking for output.

[Robert Belleman]

Tom,

[...]
> copied graphics/examplesCxx/UGrid.cxx from the vtk 2.4 distribution
> to my own directory, and added these statements at the end, just
> before the final closing brace:
> 	cout << "Smitty was here\n";
> 	cout << "sizeof(vtkUnstructuredGrid) = " 
> 		<< sizeof(vtkUnstructuredGrid) << "\n";
> I can successfully compile my modified UGrid.cxx, and the window titled
> "Visualization Toolkit - OpenGL" pops open with the image when I run
> it, but neither "Smitty was here" nor "sizeof(vtkUnstructuredGrid)=nnn"
> shows up anywhere.  Any ideas where it goes?

It goes nowhere because it never gets called...

If I remember correctly, the C++ code never returns from the function
call to "iren->Start();" (so in fact the clean up code is never called
either).

The first thing you would want to do is don't call that method, but then
you loose Vtk's event processing (i.e. rotation, panning, scaling, etc.).

Some time ago, Audrius Stundzia + Lisa suggested substituting this line
by your own event dispatching loop which would allow you to call code
while maintaining Vtk's standard event processing.
I'll append that at the end of this email. It may help you.

I have one question about the code mentioned below though: does anybody
know how you get the application context from Vtk?

Bye,
-- Rob

[] Robert Belleman         X  Section Computational Science            []
[] robbel at wins.uva.nl     |X| University of Amsterdam, the Netherlands []
[] tel: (+31) 20 525 7539  X  http://www.wins.uva.nl/~robbel/          []

-------------------------------------------------------------------------

Hi Lisa,

I celebrated the 4th by solving my problem. I can now have 2 or more
visualization windows displaying stuff concurrently and interactively
without
blocking control. I took your suggestion, then used the X Windows code in
the User Guide and wrote a modified XtAppMainLoop() in my visualization loop
that checks whether or not there are any X events pending before calling the
blocking XtAppNextEvent:

   pending = XtAppPending( context);

   if (pending > 0) 
   {
      XtAppNextEvent(  context
                    , &event );
                 
      XtDispatchEvent( &event);
   }

Thanks again for all your help.
vtk is great software backed by a great team :)

Regards, 

Audrius Stundzia

IBMG

On Fri, 02 Jul 1999 15:31:00 -0400, Lisa Sobierajski Avila wrote:

> Hi Audrius,
> 
> >
> >1. In the event loop, do I just repeatedly call aWindow->Render() for
each
> >   graphics pipeline?
> 
> No - you would write an event loop for X or Windows (I don't remember if
> you mentioned with you are using). For example, if you look at the code
for 
> XtAppMainLoop() in Xt you would need to do something like that - pull
> events off the queue and process them in a loop.
> 
> >2. Having intialized the interactor, can I use the default interaction
> >commands     to rotate, zoom, pick, etc.? The impression I get from your
> >e-mail comment
> >   "(other than interaction)" is that I can't. I need to interact with
the 
> >   actors in the windows esp. rotate and pick.
> 
> If you write an event handling loop as mentioned above all registered
> events would be processed - so you would be able to interact as always in
> each of the render windows.
> 
> 
> >3. If I can interact with the window, do I have to implement the
> >appropriate
> >   interactor callbacks (assuming  #2 is wrong)?
> >
> 
> You only have to implement any specialized ones that you would want. All
> the standard ones would work (rotate, translate, zoom, pick, etc).
> 
> 
> Lisa



-----------------------------------------------------------------------------
This is the private VTK discussion list.  Please keep messages on-topic.
Check the FAQ at: <http://www.automatrix.com/cgi-bin/vtkfaq>
To UNSUBSCRIBE, send message body containing "unsubscribe vtkusers" to
<majordomo at gsao.med.ge.com>.  For help, send message body containing
"info vtkusers" to the same address.     Live long and prosper.
-----------------------------------------------------------------------------