Hi Gunnar, Thank you for the reply,
> Is the Native OSX application also rendering via a framebuffer? As far as I understand there might in fact be a difference of one FBO between the Native OS X and the QtQuick version. Though this may depend on the implementation of the NSOpenGLView: - if NSOpenGLView creates an FBO then no, there is no difference - if NSOpenGLView give me access directly to the window buffer, then yes QtQuick drawing may go through one FBO (QQuickFramebufferObject) more. Regarding your second question > Is the same symptom present when you render directly to the QQuickWindow > using for instance the beforeRendering() signal? I’ll do some benchmark and answer you asap. Best, Bruno > Il giorno 07/set/2015, alle ore 07:35, Gunnar Sletta <gun...@sletta.org> ha > scritto: > > Hi Bruno, > > Is the Native OSX application also rendering via a framebuffer? On an Intel > GPU rendering via an FBO will add considerable cost. Is the same symptom > present when you render directly to the QQuickWindow using for instance the > beforeRendering() signal? > (http://doc.qt.io/qt-5/qtquick-scenegraph-openglunderqml-example.html) > > cheers, > Gunnar > >> On 04 Sep 2015, at 09:06, Bruno Di Giorgi <br...@brunodigiorgi.it> wrote: >> >> Dear mailing list, >> >> First time I write here, I posted this yesterday on the QtQuick forum and a >> user recommended me to post on this mailing list. >> >> I noticed some heavy cpu usage in a QtQuick (using Qt5.5) osx app compared >> to an equivalent Native OSX app. Around 5% more cpu usage with a simple app, >> up to 15% more with more complex OpenGL tasks. >> >> Both are using Core profile >> Version: 4.1 INTEL-10.6.33 >> GLSL: 4.10 >> >> In QtQuick I do openGL inside a QQuickFramebufferObject as I've seen advised >> many times. >> In OSX I draw inside a subclass of NSOpenGLView. >> >> Here are the OpenGL Profiler statistics: http://pastebin.com/uWyy8RMk >> Where you can see that CGLFlushDrawable takes so much longer in QtQuick (avg >> 15418.39 microsec) than in Native OSX App (avg 1287.65 microsec). >> >> I know that what CGLFlushDrawable really does is to set the internal OpenGL >> state and then do the drawing, so I wonder if I am misusing QtQuick OpenGL >> somehow. Here is how I set up OpenGL in QtQuick app: >> >> QSurfaceFormat f; >> f.setVersion(4, 1); >> f.setProfile(QSurfaceFormat::CoreProfile); >> QSurfaceFormat::setDefaultFormat(f); >> >> Then, when setting the framebuffer (inside QQuickFramebufferObject::Renderer >> method createFramebufferObject): >> >> QOpenGLFramebufferObjectFormat format; >> format.setAttachment(QOpenGLFramebufferObject::Depth); >> format.setInternalTextureFormat(GL_RGB); >> format.setSamples(0); >> >> I really hope there is a solution that makes me achieve similar performance >> because I really enjoy QML and I'd like to continue using it. >> >> Hardware used: >> MacBookPro 13'' with retina screen, >> cpu: 3 GHz Intel Core i7 >> gpu: Intel Iris 1536 MB >> >> Best, >> Bruno Di Giorgi >> >> _______________________________________________ >> Interest mailing list >> Interest@qt-project.org >> http://lists.qt-project.org/mailman/listinfo/interest > _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
