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
