I suggested to use an OpenGL example, not a Qt Quick one. We're trying to isolate where the issue is in the stack. So use a single threaded, plain OpenGL application with a 32 bit framebuffer and see if that gives the same issue.
Cheers, Sean On Friday 05 August 2016 14:22:00 Denis Shienkov wrote: > So, I have compiled the standard Samehame QMML application from: > > /home/builder/Projects/qt5/qtdeclarative/examples/quick/demos/samegame/ > > and got same artifacts when I use RDBA=8888 mode. > > I have "screenshoot" of this flicking attifact: > http://pasteboard.co/4XjMl3GNq.png > > I'm personally don't think that this is an NVidia's OpenGL ES2 bug... I > think it is Qt bug... > > I'm not an OpenGL expert... so, can anybody point me what I need to do with > the Qt sources (where to look in)? > > Maybe I need to add some of gl_ functions to clear of content or something > else... but where? > > 2016-08-05 12:03 GMT+03:00 Sean Harmer <sean.har...@kdab.com>: > > On Friday 05 August 2016 12:02:10 Denis Shienkov wrote: > > > > Can you try a plain OpenGL test application with RGBA8 framebuffer > > > > > > Do you mean: I should take any OpenGL application from the Qt examples? > > > > And > > > > > to check there? > > > > You may need to modify it to explicitly request R8G8B8A8 using a > > QSurfaceFormat but yes any of those should work to prove/disprove. > > > > Sean > > > > > 2016-08-05 11:53 GMT+03:00 Sean Harmer <sean.har...@kdab.com>: > > > > Hi, > > > > > > > > Can you try a plain OpenGL test application with RGBA8 framebuffer and > > > > see > > > > > > if > > > > that exhibits the same flashing/flickering problem. If so, it's a > > > > driver/hardware issue. > > > > > > > > If you are forced into then using a 16-bit framebuffer, then you can > > > > avoid > > > > > > the > > > > banding by using dithering in your gradients. Either apply the > > > > dithering > > > > > > offline > > > > and store the gradients as images or write a custom material that > > > > applies > > > > > > the > > > > dithering in the fragment shader. > > > > > > > > Cheers, > > > > > > > > Sean > > > > > > > > On Friday 05 August 2016 08:12:59 Denis Shienkov wrote: > > > > > Hi all, > > > > > > > > > > I have an idea how to avoid flickering, but I don't know about > > > > results: > > > > > what if I will discard the Open GL support in favor to Quick2 > > > > > render? > > > > > > > > > > I have read this documentation: http://doc.qt.io/QtQuick2DRenderer/ > > > > > which says about the "Qt Quick 2D Renderer" module. > > > > > > > > > > So, my things is: > > > > > > > > > > 1. Download && build && install this module: > > > > > > > > > > git://code.qt.io/qt/qtdeclarative-render2d.git > > > > > > > > > > 2. Use this env variable: > > > > > > > > > > export QMLSCENE_DEVICE=softwarecontext > > > > > > > > > > 3. Run my app... > > > > > > > > > > > > > > > But, I don't understand: > > > > > > > > > > 1) What of engine is used to 2D rendering in case if I have EGLFS > > > > only? > > > > > > > 2) Should I re-build Qt5 too with the "--no-opengl" option (or I can > > > > > keep the "-opengl es2" option) ? > > > > > > > > > > 04.08.2016 16:10, Denis Shienkov пишет: > > > > > > Hi Robin, > > > > > > > > > > > > > Repeating my last answer... > > > > > > > http://lists.qt-project.org/pipermail/development/2016-> > > > > > > > > > July/026736.html > > > > > > > > > > I'm sorry, but I did not receive (did not see) your last answer. > > > > > > > > > > > > > I'm going to guess you're using eglfs or something like that > > > > > > > > > > > > Yes, I use EGLFS via X11 on Linux Apalis T30 board, where are used > > > > > > NVIDIA's drivers. > > > > > > > > > > > > Seems, the flickering is when are used: > > > > > > > > > > > > export QT_QPA_EGLFS_FORCE888=1 > > > > > > > > > > > > ENV variable... (I need this variable to smooth the Image's > > > > > > gradients... even X11 started with 24-bit depth). > > > > > > > > > > > > PS: But, I'm not sure about QT_QPA_EGLFS_FORCE888... :( > > > > > > > > > > > > > Using an overlay to debug item positions > > > > > > > (QSG_VISUALIZE=overdraw) > > > > > > > > > > > > could be handy for trying to rule > > > > > > this out, as if it is specific to the application, > > > > > > > > > > > > Ok, many thanks, I will try it. > > > > > > > > > > > > > > > > > > 2016-08-04 14:57 GMT+03:00 Robin Burchell <robin...@viroteck.net > > > > > > > > > > > > <mailto:robin...@viroteck.net>>: > > > > > > Repeating my last answer... > > > > > > > > > > > > http://lists.qt-project.org/pipermail/development/2016-> > > > > > > > > > July/026736.htm > > > > > > > > > > l > > > > > > > > > > > > On Thu, Aug 4, 2016, at 01:50 PM, Denis Shienkov wrote: > > > > > > > {quote} > > > > > > > > > > > > > > Hi all. > > > > > > > > > > > > > > I have some QML application, where just use QQuickView as > > > > > > > QML > > > > > > > > > > > > container. > > > > > > > > > > > > > This application uses Qt 5.7.x and running on Linux embedded > > > > > > > > > > > > board with > > > > > > > > > > > > > the > > > > > > > NVIDIA core (Toradex Apalis T30). > > > > > > > > > > > > > > But sometimes I got flickering in process of animation. A > > > > > > > > flickering > > > > > > > > > > > represents in form of a "white" strips with full-screen > > > > > > > width > > > > > > > > > > > > and 1/5-1/6 > > > > > > > > > > > > > screen heigth. This flickers happens quickly and frequently > > > > > > > > > > > > (every ~20-60 > > > > > > > > > > > > > seconds, randomly)... > > > > > > > > > > > > > > I have seen this "Avoiding graphics flicker in Qt / QML" [1] > > > > > > > > > > > > blog where > > > > > > > > > > > > > are > > > > > > > used QML with Qt 4.x, > > > > > > > where were used this trics: > > > > > > > > > > > > > > {code} > > > > > > > int main(int argc, char **argv) > > > > > > > { > > > > > > > > > > > > > > ... > > > > > > > > > > > > > > view.setAttribute(Qt::WA_OpaquePaintEvent); > > > > > > > view.setAttribute(Qt::WA_NoSystemBackground); > > > > > > > view.viewport()->setAttribute(Qt::WA_OpaquePaintEvent); > > > > > > > view.viewport()->setAttribute(Qt::WA_NoSystemBackground); > > > > > > > > > > > > > > ... > > > > > > > > > > > > > > } > > > > > > > {code} > > > > > > > > > > > > > > But, in my case I have use Quick v2, with QQuickView instead > > > > of > > > > > > > > > QDeclarativeView, > > > > > > > which does not allowed to setup any attributes. > > > > > > > > > > > > > > So, my questions is: is there are any way to setup > > > > > > > Qt::WA_OpaquePaintEvent > > > > > > > and/or > > > > > > > Qt::WA_NoSystemBackground in Quck2? Or, maybe is it possible > > > > to > > > > > > use > > > > > > > > > > > another > > > > > > > tricks? > > > > > > > > > > > > > > BR, > > > > > > > Denis > > > > > > > > > > > > [1]https://blog.rburchell.com/2011/11/avoiding-graphics-> > > > > > > > > > flicker-in-qt-> > qml.html> > > > > > > > > > > > {quote} > > > > > > > > > > > > > > This flickering present on some HDMI displays... > > > > > > > > > > > > > > We currently have this flags: > > > > > > > > > > > > > > {code} > > > > > > > ... > > > > > > > view.setFlags(Qt::FramelessWindowHint | > > > > > > > > Qt::WindowStaysOnTopHint); > > > > > > > > > > > ... > > > > > > > {code} > > > > > > > > > > > > > > Maybe is it an reasons of flikering? Has someone any ideas? > > > > > > > > > > > > > > BR, > > > > > > > Denis > > > > > > > _______________________________________________ > > > > > > > Development mailing list > > > > > > > Development@qt-project.org <mailto:Development@qt- > > > > project.org> > > > > > > > > > http://lists.qt-project.org/mailman/listinfo/development > > > > > > > > -- > > > > Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK > > > > KDAB (UK) Ltd, a KDAB Group company > > > > Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090 > > > > Mobile: +44 (0)7545 140604 > > > > KDAB - Qt Experts > > > > _______________________________________________ > > > > Development mailing list > > > > Development@qt-project.org > > > > http://lists.qt-project.org/mailman/listinfo/development > > > > -- > > Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK > > KDAB (UK) Ltd, a KDAB Group company > > Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090 > > Mobile: +44 (0)7545 140604 > > KDAB - Qt Experts -- Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK KDAB (UK) Ltd, a KDAB Group company Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090 Mobile: +44 (0)7545 140604 KDAB - Qt Experts _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development