Re: [osg-users] Draw thread per opengl context instead of per GraphicsContext
Hi Robert, Ah ok, so the GraphicsContext::Traits::sharedContext doesn't share the actual context, but allows object sharing between contexts. Thanks for clearing that up for me, I think this changes what I am looking for. The reason that I am looking into this, is because of the following measurements. In all tests, the screenspace view sizes and rendered objects are the same. 1. 6 views in one window (singlethreaded) 24.3 fps 2. 6 views in one window (multithreaded)46 fps In these two tests, we have 1 context and 1 draw thread. Enabling multithreading almost doubles the performance. So, performing culling on another thread proves to be very effective. 3. 6 views in separate windows (multithreaded) 11.7 fps 4. 6 views in separate windows with context sharing (singlethreaded)22 fps The last test cannot be done with multiple render threads, which makes sense. But I think (please correct me if I'm wrong), multiple separate cull threads should have no effect on it's correct operation. Looking at the performance difference between test 1 and 2, I am eager to see what culling on a different thread(s) would do here. So my question changes to: for test 4, is it possible to still use separate cull threads while we only use 1 draw thread. And if not, could you give us pointers on what should be taken into consideration if we want to implement this. Thanks! Cheers, Ben -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=72376#72376 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Draw thread per opengl context instead of per GraphicsContext
Hi Robert, Thanks again for your quick response. Isn't an opengl context already used by multiple windows when you use GraphicsContext::Traits::sharedContext ? I also came across the following function: BOOL WINAPI wglMakeCurrent( HDC hdc, HGLRC hglrc ); A window device context can be specified here, so it would seem that you can change the window. I also came across the following: https://blog.gvnott.com/some-usefull-facts-about-multipul-opengl-contexts/ This also seems to state that a single opengl context can be used to render to multiple windows. Thank you! Cheers, Ben -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=72355#72355 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Draw thread per opengl context instead of per GraphicsContext
Hi Robert, Thank you for your response. I don't want to share the context or GL objects in multiple threads. Basically what I want is 1 draw thread for the 1 opengl context if have and 1 cull thread. I want this 1 opengl context to be shared by multiple windows. However, for each window that I create, a new draw thread is created, even when they share the same opengl context. So I was hoping that it was possible to have 1 draw thread per opengl context, instead of 1 draw thread per window (GraphicsContext). The opengl context would only be used by one thread, so thread safety shouldn't be an issue right? Cheers, Ben -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=72353#72353 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Draw thread per opengl context instead of per GraphicsContext
Hi everyone, I want to use the GraphicsContext::Traits::sharedContext to render multiple views (in multiple windows) that share the same context. I already read on some forums that the ThreadingModel::SingleThreaded should be used. However, I would still like to use ThreadingModel::DrawThreadPerContext so that the cull and draw thread can overlap. I tried this, but a draw thread is created per GraphicsContext and thus per window. Because all these windows share an opengl context, I would have expected that only 1 thread would have been created. This results in all sorts of problems. Is there a way in which I can use 1 draw thread per opengl context ? And, if not, is this something that I can easily change by modifying the code ? Thank you! Cheers, Ben -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=72344#72344 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
