>>> We are using SceneView from OSG 1.2 and VR Juggler in a >>> multiple render thread environment. We are using the >>> osgUtil::UpdateVisitor to update the graph in a serial >>> portion of our code. SceneView::cull and SceneView::draw are >>> called from each rendering thread. In this configuration we >>> often see the displays flash the clear color on a random >>> basis. We are setting the clear color through the use of a >>> ClearNode and we clear the depth buffer at the beginning of >>> the draw function. >> >> Hi Doug -- Just thinking of this in OpenGL terms, the dreaded "blank >> screen" >> can have many many causes. >> >> One possible explanation: The cull traversal on one of the displays >> randomly >> thinks that everything is culled. This could be due to a configuration >> issue >> for the camera controlling that display, the modelview/projection >> matrices >> are bogus and/or the view volume used during the cull traversal isn't >> set >> correctly. You might consider hacking the code to dump such information >> out >> per frame. Yes, it will generate gobs of output, but if you do a short >> run >> and see a flash, then examine the debug output, any one-frame >> irregularities >> should jump out at you. If nothing shows up, then the problem is >> somewhere >> else. >> > If I make the SceneView::cull call guarded with a mutex then the problem > goes away. I printed out the frustum values and view matrix and nothing > seemed to be wrong there. Any ideas on what might not be thread safe in > cull or what I may be doing wrong with my management of cull settings? > Also, this code is not using anything special in terms of hardware > occlusion culling or the small feature culling. > >> The other thought I had relates to the ClearNode. Does the problem go >> away >> if you eliminate the ClearNode and just let SceneView do its own >> clearing? >> -Paul >>
I am still seeing these problems with the osg HEAD as well. Any more suggestions on things to try or look into? Doug _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
