Hi Steve,
On quick review of your email it seems like you event handler is
deleting itself when the view its associated with is deleted, and also
invalidating the iterator the CompositeViewer is using.
The way to fix this is to avoid deleting the view within the callback,
by doing the delete in the main frame loop. This will complicate the
callback and main loop a bit as you need to create some mechanism for
coordinating the deletion operation, but it should work fine.
Robert.
On Wed, Feb 6, 2008 at 6:12 PM, Steve Schneider <[EMAIL PROTECTED]> wrote:
> Compositeview: Two views. Big View and Little View. Big View is loaded
> with the image of a Cessna going down in flames with the example 'Scribe'
> event handler. Little View is the beginnings of a user interface.
>
> So based on a pick - another view is created, populated and an eventhandler
> is attached. Very cool.
>
> Now - based on a pick - I want to tear down said view and eventhandler. So
> I try some variant of:
> >
> >osgViewer::View* DoomedView = viewer->getView(ViewIndex);
> >// break down the camera as much as possible.
> >DoomedView->getCamera()->setAllowEventFocus(false);
> >unsigned int DoomedChildren = DoomedView->getCamera()->getNumChildren();
> >DoomedView->getCamera()->removeChildren(0,DoomedChildren);
> >viewer->removeView(DoomedView);
> >
> in an event handler of the Little View.
>
> So I follow the process and eventually get to:
> CompositeViewer::eventTraversal()
>
> for(ViewEventsMap::iterator veitr = viewEventsMap.begin();
> veitr != viewEventsMap.end();
> ++veitr)
> {
> View* view = veitr->first;
> -->
> -->At this point in the execution 'view' is pretty thrashed - probably
> referencing the
> --> view that no longer there??? There are no event handlers associated
> with
> --> this view. I point this out to build the drama. :)
> -->
> _eventVisitor->setActionAdapter(view);
>
> for(osgGA::EventQueue::Events::iterator itr = veitr->second.begin();
> itr != veitr->second.end();
> ++itr)
> {
> osgGA::GUIEventAdapter* event = itr->get();
> for(View::EventHandlers::iterator hitr = view->getEventHandlers().begin();
> hitr != view->getEventHandlers().end();
> ++hitr)
> -->
> --> At this point I try to wave it off: Stop! Stop!. There are no event
> handlers!
> --> Don't look for a begining and an end to nothing. Please!
> --> All in vain . . .
> --> Everyone in the audience can see it coming. Everyone in the cast and
> crew.
> --> The only one ignorant of his/her fate is the hero of the story.
> -->
> std::list
> iterator begin()
> { // return iterator for beginning of mutable sequence
> return (iterator(_Nextnode(_Myhead), this));
> }
> -->
> --> Access violation reading address XYZ. There is no _Nextnode of
> _Myhead.
> --> I told the computer to stop but would it listen? Oh no.
> --> In my despair I wonder if it would've listened to my warnings about the
> white rabbit.
> --> Probably not - even with the supporting evidence of all the bones.
> -->
>
> Now a clever programmer like myself could simply add a check for this and
> skip over the offending check in the CompositeViewer. I could also pour
> sand into the gears of a finely crafted clock. I'm not in my 20's anymore,
> and so I figured I present my case and let those wiser then myself offer
> guidance. That I learned in my 30's. :)
>
> -Steve Schneider
>
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>
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