Dear all, For the use of further VirtualGL users, here are my answers (if it can be called so) to the problem I had:
In paintEvent(QPaintEvent *e) we were calling swapBuffers(); However, in nokia' documentation, i twas stated that: http://doc.qt.nokia.com/4.6/qglwidget.html#swapBuffers <<void QGLWidget::setAutoBufferSwap ( bool on ) [protected]>> If on is true and the widget is using a double-buffered format, the background and foreground GL buffers will automatically be swapped after each paintGL() call. The buffer auto-swapping is on by default. This means we were actually re-swapping the buffer. Although this had no effect locally, it had a huge negative impact with VirtualGL (that actually helped us realize our mistake). Simply removing the unjustified call to the additional swapBuffers() solved our problem. As such, VirtualGL 2.2alpha is working perfectly well. Regards, -----Original Message----- From: DRC [mailto:[email protected]] Sent: Sunday, April 11, 2010 7:30 PM To: [email protected] Subject: Re: [VirtualGL-Users] QT + VirtualGL = black viewport flickering - no display There should not be a significant performance change in VGL 2.2 alpha, and in fact some users have observed it to be faster than previous releases. We are no longer using TurboJPEG/IPP, but we are using libjpeg-turbo, which is a fully open source codec with approximately the same performance. With 2.2 alpha, you can set VGL_LOGO=1 to verify that VirtualGL is indeed activated (if so, it will display a VGL logo in the lower right corner of the 3D rendering area.) On 4/11/10 4:27 PM, Flo wrote: > I built a small app over the week-end ... to realize that it does not > reproduce the issue. > Every Qt openGL code and mine is running, but the app I want. > > However, I find a previous version of our app that is working (only with > VirtualGL 2.2alpha, seg fault with any other previous versions). I know we > did some speed improvement regarding Qt pixmap issues so I will dig into > that and let the mailinglist know as soon as I found which one of our > "improvements" caused this prob. > > I will send a small app reproducing the issue as soon as I found which part > of the code creates it. > > Now, the version of our app that works with VirtualGL2.2alpha is very slow. > Checking the release notes I saw you are not using the TurboJpeg anymore. Is > there a known decrease in performance with this change ? (glxgears is not > slow at all ... only our app .... again !) > > Best regards and thanks for the quick replies. > > Flo. > > -----Original Message----- > From: DRC [mailto:[email protected]] > Sent: Friday, April 09, 2010 1:52 AM > To: VirtualGL Users > Subject: Re: [VirtualGL-Users] QT + VirtualGL = black viewport flickering - > no display > > I'm not sure it is the same issue. Alex's issue was specific to MITK, > and he was able to resolve it by upgrading to a new version. > > Does your app use VTK or Qt or both? Is it something that could be > reproduced with a simple test application that I could build and run here? > > On 4/8/10 10:24 PM, Flo wrote: >> Dear All, >> >> I have an issue that was previously reported on you mailinglist here and >> not answered: >> > _http://sourceforge.net/mailarchive/message.php?msg_id=cbb4c0f20802191246o28 > [email protected]_ >> >> Specifically, I have a Qt application that uses 2D and 3D rendering in >> viewports. Although fine as standalone, when used through VirtualGL, >> every viewport (2D or 3D) is black. The only moment when I can see the >> proper content is by creating a mouse event (movement, click and else), >> where it flickers and for a second I can see the proper content before >> it becomes black again. >> >> I tried many combination of VirtualGL options but it seems not to do any >> good. >> >> The VirtualGL server is a SLED 11, although using few Suse OSS 11.2 >> repo, 64-bits and NVidia video card. >> >> "from what have been said: It sounds like if the >> >> OpenGL buffer is not flushed properly. >> >> We are also aware of problems with some OpenGL drivers, beside the >> >> ones from Nvidia, where setting the VTK rendering mode to "immediate" >> >> may help." >> >> But it didn't go any further in the thread. >> >> Any help would be greatly appreciated. >> >> Flo. >> >> >> >> > ---------------------------------------------------------------------------- > -- >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> >> >> >> _______________________________________________ >> VirtualGL-Users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/virtualgl-users > > ---------------------------------------------------------------------------- > -- > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > VirtualGL-Users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/virtualgl-users > > > ---------------------------------------------------------------------------- -- > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > VirtualGL-Users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/virtualgl-users ---------------------------------------------------------------------------- -- Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ VirtualGL-Users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtualgl-users ------------------------------------------------------------------------------ _______________________________________________ VirtualGL-Users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtualgl-users
