[osg-users] Problems shutting down Composite Viewer/View/Custom drawables

Cole, Charles E. (LARC-B702)[RAYTHEON TECHNICAL SERVICES COMPANY] charles.e.cole at nasa.gov
Fri Mar 27 10:21:46 PDT 2009


Hi all,

I forgot to mention in my long-winded post that I'm using OSG 2.8.0.

chuck

> -----Original Message-----
> From: osg-users-bounces at lists.openscenegraph.org [mailto:osg-users-
> bounces at lists.openscenegraph.org] On Behalf Of Cole, Charles E. (LARC-
> B702)[RAYTHEON TECHNICAL SERVICES COMPANY]
> Sent: Friday, March 27, 2009 12:51 PM
> To: OpenSceneGraph Users
> Subject: [osg-users] Problems shutting down Composite
> Viewer/View/Custom drawables
> 
> Hi all,
> 
> I've been chasing an error in my code for many, many days that I'm
> hoping that someone can help me track down.  I'll try to explain my
> application as best I can.
> 
> I'm using a composite viewer to load multiple views.  In each view, I'm
> loading a database scene (generally a TXP database) and overlaying
> OpenGL nodes that I load dynamically and add as drawables to the
> scenegraph.  I've created classes to encapsulate the composite viewer,
> view, and scene nodes.  For instance, I have a class that contains a
> composite viewer member variable; this class then creates multiple
> "View" classes that each contain an osgViewer::View member variable.
> Each view then loads scene nodes as specified in a configuration file.
> These nodes are contained in separate libraries and are loaded as
> drawables (I've created a class derived from osg::Drawable and
> overwrite the drawImplementation method for custom drawing).
> Everything works great when creating the viewer, view, nodes, and even
> executing.  The problem comes when I try to destroy/close the window.
> 
> My attempted process to close is that I (1) set a flag on a render
> thread to stop calling viewer->frame (very similar to setDone(true));
> (2) destroy the loaded drawables and free their associated libraries;
> (3) destroy the view, and thus it's associated camera and graphics
> context; and (4) destroy the composite viewer.  I use reference
> pointers in every case except for the composite viewer (although I've
> tried a reference pointer for it as well, but still get the same
> result).
> 
> When trying to follow the above process, the application crashes in the
> Node::releaseGLObjects method at line 523, if (_updateCallback.valid())
> _updateCallback.releaseGLObjects(state).
> 
> I also noticed during a debug walkthrough that the drawables
> drawImplementation method (and thus the custom drawable's own custom
> drawing methods) are still being called after the render thread has
> been stopped and destroyed.
> 
> So, some of my many questions are:
> 
> (1) Is there a preferred/required means or order for shutting down a
> composite viewer (and it's child nodes)?
> 
> (2) Separately, but possibly related ... I create a camera callback
> function to update the camera position per shared memory variables.
> I'd like to destroy that callback function appropriately.  But, in
> doing so, how do I reset the camera's callback function such that it's
> not called once the custom callback function is destroyed?
> 
> (3) What's the appropriate means of stopping the rendering?  I thought
> that if viewer->frame() wasn't getting called, the drawImplementation
> method of the drawables would no longer be called, so I could then free
> those libraries.  But, unfortunately, they're still being called even
> though frame() is no longer called.  And thus, the libraries are trying
> to be freed when the viewer is still trying to draw them.
> 
> I am running multithreaded.  I'm using VS 2008 SP1 on Windows XP and
> Vista.
> 
> If anyone has any tips, pointers, something to point me in the right
> direction before I end up throwing the computer through the window, I'd
> greatly appreciate it.  I hope I've provided enough information.
> 
> Thanks so much in advance.
> 
> Chuck
> 
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