Hi, the issue is, that if the qt application window is minimized, then the occlusion queries always return 0 as the number of passed pixels.
I don't think that this is an OpenSceneGraph issue, but I'm hoping to get some hints here what the reasons of the issue might be, because at the moment I'm pretty much out of ideas. We're having a Qt based application, a QGLWidget for the rendering area and using a 'osgUtil::SceneView' for the rendering of the scene. For the occlusion queries we don't use OpenSceneGraph functionality, but directly use the OpenGL extensions GL_NV_occlusion_query or GL_ARB_occlusion_query. Both extensions behave in the same way for this case. An application session can be recorded into a script - which might also include taking snapshots of the 3d scene - and the script can be executed afterwards and should produce the same snapshots. The application has a "no gui" mode, which runs the application with a minimized qt window and is mostly used for the script execution. Now everything regarding snapshots works in the "no gui" mode, beside of the occlusion queries, which always return 0 as the number of passed pixels. Now we also have a "no display" mode of the application, to be able to run scripts on servers without graphics hardware, by using the Mesa OpenGL library, and in this case the occlusion queries work like expected. The biggest difference on the Qt side in this case seems to be that the instanciated QApplication is of type TTY. It's also possible to run the version using the Mesa library in "no gui" mode, in which case I'm getting yet another result, the occlusion query then returns some passed pixels, but the result is wrong. At the moment I'm pretty much perplexed how I should interpret these different results and I could reproduce them on different linux machines with different graphics cards and drivers. We're using at the moment OpenSceneGraph-3.0.1 and Qt-4.6.3 (we're porting to Qt-5.9.4, which gives the same results). My local machine: System: Ubuntu 16.04 Graphics Card: GeForce GTX 970 Driver: NVIDIA 375.39 I greatly appreciate any kind of ideas what might be the issue here. Thanks! Greetings, Daniel _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
