[Interest] QML animation flicker

[Thomas Senyk]

I can validate the problem.

For me it happens only(!) during the ColorAnimations.
If I either comment those, or set the RadialGradient visible: false
the "stuttering" is gone.

It's not stuttering with Rectangle

The Qt build is a checkout from this week on 64bit ArchLinux (updated this 
week) and qtgraphicaleffects are up-to-date from today.



Greets
Thomas



On Fri, October 19, 2012 10:44:04 AM Jarno Seppänen wrote:
> I tested on two more machines with Nvidia graphics, can reproduce the
> flicker on both: Ubuntu 12.10 with Asus GT520 running Qt5 beta 1,
> other with Ubuntu 12.04 and Quadro FX 3800 running Qt5 master branch
> from Oct 14th. The previous machines I tested with had Intel graphics
> (Poulsbo and GMA4500MHD).
> 
> The flicker disappears if "Sync to VBlank" is turned off from OpenGL
> Settings in nvidia settings panel (but other problems appear,
> obviously).
> 
> Jarno
> 
> On Thu, Oct 18, 2012 at 10:10 PM, Jarno Seppänen <jarno.seppanen at iki.fi> 
wrote:
> > hi,
> > 
> > On Mon, Oct 15, 2012 at 11:29 AM, Samuel Rødal <samuel.rodal at digia.com> 
wrote:
> >> On 10/12/2012 11:10 PM, Jarno Seppänen wrote:
> >>> Hi,
> >>> I'm trying out Qt 5.0.0-beta1, but I'm seeing some unexpected
> >>> animation flicker. I have a rotating rectangle which starts to flicker
> >>> during a simultaneous ColorAnimation, without it the rotation is
> >>> smooth. Is this an issue with my setup and should I change my QML code
> >>> somehow? I've gotten similar results on two Ubuntu laptops, running
> >>> 11.04 and 12.04.
> >> 
> >> Hmm, I was not able to reproduce this with a recent build of Qt 5. What
> >> kind of flicker are you talking about?
> > 
> > The animation movement jerks back and forth very fast, as if every two
> > frames were being displayed in swapped order. The effect is especially
> > disturbing on scrolling text. I tried to capture a video of the
> > flicker, but it seems that the screen recording software does
> > something that makes the problem disappear. I also noticed that the
> > flicker is much diminished if I run qmlscene in a window, running qml
> > --fullscreen gives "best" flicker.
> > 
> > Example with text flicker:
> > 
> > import QtQuick 2.0
> > import QtGraphicalEffects 1.0
> > 
> > FocusScope {
> > 
> >     id:screen
> >     
> >     SequentialAnimation {
> >     
> >         loops: Animation.Infinite; running: true
> >         PauseAnimation { duration: 1000 }
> >         ColorAnimation { target: glow; property: "color"; to: "navy";
> > 
> > duration: 1000; easing.type: Easing.InOutQuad }
> > 
> >         PauseAnimation { duration: 1000 }
> >         ColorAnimation { target: glow; property: "color"; to: "blue";
> > 
> > duration: 1000; easing.type: Easing.InOutQuad }
> > 
> >     }
> >     
> >     RadialGradient {
> >     
> >         gradient: Gradient {
> >         
> >             GradientStop { id: glow; position: 0.0; color: "blue" }
> >             GradientStop { position: .7; color: "blue" }
> >         
> >         }
> >         anchors.fill: parent
> >     
> >     }
> >     
> >     Text {
> >     
> >         id:txt
> >         width:600
> >         color:"white"
> >         text: "Lorem ipsum dolor sit amet, consectetur adipisicing
> > 
> > elit, sed do eiusmod tempor incididunt ut labore et dolore magna
> > aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco
> > laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor
> > in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
> > pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
> > culpa qui officia deserunt mollit anim id est laborum."
> > 
> >         font.weight:Text.Bold
> >         font.pointSize:30
> >         wrapMode: Text.Wrap
> >         NumberAnimation on y {
> >         
> >             from:-txt.contentHeight
> >             to:txt.contentHeight+500
> >             loops:-1
> >             duration:6000
> >         
> >         }
> >         anchors.horizontalCenter:parent.horizontalCenter
> >     
> >     }
> > 
> > }
> > 
> > Jarno
> 
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