J-S, Yes, a great point I failed to bring up about the mutex. Thanks for mentioning that. We did have to do that to protect the shared resource when we used threading.
For our stuff, one process (out-the-window) does the usual traversal (via viewer.frame) while the other sits idle until a request comes in for either HAT/HOT or LOS. Once a request comes in, it just computes the intersection with the terrain via the osgSim class and sends the scalar result back. Both processes load the same PagedLOD terrain node but they're using completely different graphs. We only check for intersection with terrain and nothing else... -Shayne -----Original Message----- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Jean-Sébastien Guay Sent: Thursday, May 12, 2011 2:37 PM To: OpenSceneGraph Users Subject: Re: [osg-users] Intersection testing in a separate thread Hi Shayne, Craig, > Bottom line is that it can be done. It basically amounts to having > asynchronous traversal of the same scenegraph, one for rendering traversal > and the other for intersections. These traversals can either be done in > different threads or different processes. But the case of a different thread vs a different process is not the same. In his case, there will be (optimally) one copy of the scene graph, and both the rendering and the intersection thread will access it. He will need a mutex which would be held by the rendering thread while it's in the update phase, and by the intersection thread while it does an intersection. In your case, you have two copies of the scene graph, so there are no threading issues. (how did you update the scene graph between processes?) But that doesn't mean it can't be done, just that it's not quite as simple as that. Hope this helps, J-S -- ______________________________________________________ Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com http://www.cm-labs.com/ http://whitestar02.dyndns-web.com/ _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
