Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-08 Thread Denis Shienkov 
> BUT: If I use resize(w, h+1) or resize(w, h-1), then, seems I do not see
any flickers.

Sorry, but with XCB also flickered. :(

2016-08-08 14:05 GMT+03:00 Denis Shienkov :

> > Can you try the regular xcb qpa plugin and see whether that has the same
> behavior?
>
> Yes, I have tested it with XCB and see the same issue. But only when I use
> fullScreen() or resize(w, h), where 'w' and 'h' it is native screen size.
>
> BUT: If I use resize(w, h+1) or resize(w, h-1), then, seems I do not see
> any flickers.
>
>
> 2016-08-05 20:11 GMT+03:00 Louai Al-Khanji :
>
>>
>> > On Aug 4, 2016, at 6:10 AM, Denis Shienkov 
>> wrote:
>> > > 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.
>> >
>>
>> Can you try the regular xcb qpa plugin and see whether that has the same
>> behavior?
>>
>> Cheers,
>> Louai
>>
>>
>>
>
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-08 Thread Denis Shienkov 
> Can you try the regular xcb qpa plugin and see whether that has the same
behavior?

Yes, I have tested it with XCB and see the same issue. But only when I use
fullScreen() or resize(w, h), where 'w' and 'h' it is native screen size.

BUT: If I use resize(w, h+1) or resize(w, h-1), then, seems I do not see
any flickers.


2016-08-05 20:11 GMT+03:00 Louai Al-Khanji :

>
> > On Aug 4, 2016, at 6:10 AM, Denis Shienkov 
> wrote:
> > > 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.
> >
>
> Can you try the regular xcb qpa plugin and see whether that has the same
> behavior?
>
> Cheers,
> Louai
>
>
>
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Louai Al-Khanji 

> On Aug 4, 2016, at 6:10 AM, Denis Shienkov  wrote:
> > 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.
> 

Can you try the regular xcb qpa plugin and see whether that has the same 
behavior?

Cheers,
Louai




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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
UPD: Now, I have running the qopenglwindow example application with
QT_QPA_EGLFS_FORCE888=1 and see that flickering artifacts occurred
sometimes.
It is an interest moment, that without QT_QPA_EGLFS_FORCE888, the OpenGL
draws the rectangle more slowly.

2016-08-05 16:47 GMT+03:00 Denis Shienkov :

> > Just change example, as you picked one which uses multiple TLWs...
>
> I haven't found an example which works with the OpenGL ES2. I have tried
> "hellogles3" application, but it failed too.
>
> UPD: When I use RGBA in QML, then I see following debug messages:
>
> {quote}
> qt.scenegraph.general: animation driver switched to timer mode
> qt.scenegraph.general: animation driver switched to vsync mode
> qt.scenegraph.general: animation driver switched to timer mode
> qt.scenegraph.general: animation driver switched to vsync mode
> qt.scenegraph.general: animation driver switched to timer mode
> {quote}
>
> is it normal?
>
>
>
> 2016-08-05 16:16 GMT+03:00 Giuseppe D'Angelo :
>
>> On Fri, Aug 5, 2016 at 2:56 PM, Denis Shienkov 
>> wrote:
>> > EGLFS: OpenGL windows cannot be mixed with others.
>>
>> Just change example, as you picked one which uses multiple TLWs...
>>
>> --
>> Giuseppe D'Angelo
>>
>
>
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
> Just change example, as you picked one which uses multiple TLWs...

I haven't found an example which works with the OpenGL ES2. I have tried
"hellogles3" application, but it failed too.

UPD: When I use RGBA in QML, then I see following debug messages:

{quote}
qt.scenegraph.general: animation driver switched to timer mode
qt.scenegraph.general: animation driver switched to vsync mode
qt.scenegraph.general: animation driver switched to timer mode
qt.scenegraph.general: animation driver switched to vsync mode
qt.scenegraph.general: animation driver switched to timer mode
{quote}

is it normal?



2016-08-05 16:16 GMT+03:00 Giuseppe D'Angelo :

> On Fri, Aug 5, 2016 at 2:56 PM, Denis Shienkov 
> wrote:
> > EGLFS: OpenGL windows cannot be mixed with others.
>
> Just change example, as you picked one which uses multiple TLWs...
>
> --
> Giuseppe D'Angelo
>
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Giuseppe D'Angelo 
On Fri, Aug 5, 2016 at 2:56 PM, Denis Shienkov  wrote:
> EGLFS: OpenGL windows cannot be mixed with others.

Just change example, as you picked one which uses multiple TLWs...

-- 
Giuseppe D'Angelo
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
>> I suggested to use an OpenGL example
> Pure Open GL example does not work at all (e.g. I tried Cube example).. I
see only a black screen, and some of OpenGL textures errors.

Also I have tried to use an ContextInfo example, where it is possible to
choose an OpenGL or OpenGL ES.

1. So, when it is selected OpenGL, then app says that it is impossible to
create a context:

{quote}
Requesting surface format QSurfaceFormat(version 2.0, options QFlags(),
depthBufferSize 16, redBufferSize -1, greenBufferSize -1, blueBufferSize
-1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior 0,
swapInterval 1, profile  0)
Cannot find EGLConfig, returning null config
QEGLPlatformContext: Failed to create context: 3005
{quote}

2. So, when it is selected OpenGL ES, then app crashed:

{quote}
Requesting surface format QSurfaceFormat(version 2.0, options QFlags(),
depthBufferSize 16, redBufferSize -1, greenBufferSize -1, blueBufferSize
-1, alphaBufferSize -1, stencilBufferSize -1, samples -1, swapBehavior 0,
swapInterval 1, profile  0)
EGLFS: OpenGL windows cannot be mixed with others.
sh: line 1:  1842 Aborted DISPLAY=':0.0'
/home/root/deploy-apps/contextinfo
Application finished with exit code 134.
{quote}


So, it is impossible for me check it with pure OpenGL at all..



2016-08-05 14:53 GMT+03:00 Denis Shienkov :

> > I suggested to use an OpenGL example
>
> Pure Open GL example does not work at all (e.g. I tried Cube example).. I
> see only a black screen, and some of OpenGL textures errors.
>
> PS: I have crerated a bug https://bugreports.qt.io/browse/QTBUG-55162
> (just in case)
>
> 2016-08-05 14:39 GMT+03:00 Sean Harmer :
>
>> 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= 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 :
>> > > 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 :
>> > > > > 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/QtQuick2DRend
>> erer/
>> > > > > > 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) Sho

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
> I suggested to use an OpenGL example

Pure Open GL example does not work at all (e.g. I tried Cube example).. I
see only a black screen, and some of OpenGL textures errors.

PS: I have crerated a bug https://bugreports.qt.io/browse/QTBUG-55162 (just
in case)

2016-08-05 14:39 GMT+03:00 Sean Harmer :

> 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= 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 :
> > > 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 :
> > > > > 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
> > > > > > >
> > > > > > >

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Sean Harmer 
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= 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 :
> > 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 :
> > > > 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  > > > > > 
> > > > > > >:
> > > > > > 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.
> > > > > > 
> > > > > > > Thi

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
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= 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 :

> 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 :
> > > 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  > > > >
> > > > > >:
> > > > > 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
> > > >

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Sean Harmer 
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 :
> > 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  > > > 
> > > > >:
> > > > 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 ques

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Denis Shienkov 
> 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?

2016-08-05 11:53 GMT+03:00 Sean Harmer :

> 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  > >
> > > >:
> > > 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::

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-05 Thread Sean Harmer 
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  > 
> > >:
> > 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 
> > > http://lists.qt-project.org/mailman/listinfo/development

--

Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-04 Thread Denis Shienkov 

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 >:


Repeating my last answer...

http://lists.qt-project.org/pipermail/development/2016-July/026736.html

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 
> http://lists.qt-project.org/mailman/listinfo/development




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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-08-04 Thread Denis Shienkov 
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 :

> Repeating my last answer...
>
> http://lists.qt-project.org/pipermail/development/2016-July/026736.html
>
> 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
> > http://lists.qt-project.org/mailman/listinfo/development
>
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Re: [Development] [QML] Avoiding graphics flicker in Quick2

2016-07-29 Thread Robin Burchell 
On Thu, Jul 28, 2016, at 02:37 PM, Denis Shienkov wrote:
> 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?

Ah, the memories. Good times.

Unfortunately for you, QQ2 is a very different beast. Rendering is done
using OpenGL (unless you're using a different scenegraph backend, but
that's probably not very likely right now) and then pushed to the
windowing system of your choice using a QPA plugin via QWindow (how
exactly this is done, of course, depends on your windowing system & the
QPA plugin you are using).

If you're seeing flickering, this means you have four possibilities,
ranked in no real order:

1) OpenGL driver bug (the world is full of them..)
2) Application-side bug (make sure you don't have anything that could be
flickering in your application). 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, you'd see which part
of the application is flickering - and the overlay wouldn't be affected.
3) A problem or bug with the QPA plugin you're using (you mention
embedded, so I'm going to guess you're using eglfs or something like
that)
4) Relatedly, a problem or bug with the windowing system (particularly
if you're doing something rather custom. If you're using e.g. OS X or
some other mainstream setup though, this is less likely)

-- 
  Robin Burchell
  ro...@viroteck.net
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