Hi,
On Monday 25 April 2016 16:23:31 Ramy Atalla via Interest wrote:
> Hi,I am trying to do a rotation animation and control the rotation speed by
> changing the value of the duration, But it doesn't work . My question is it
> feasible or there another way ?
>
> QQ2.NumberAnimation { id:wheelanimation property int carspeed:0
> targets: [wheel1Transform , rim1Transform,wheel2Transform ,
> rim2Transform,wheel3Transform , rim3Transform,wheel4Transform ,
> rim4Transform] property: "userAngle" duration: carspeed from: 0
> to: 360 loops: QQ2.Animation.Infinite running: true }
> QQ2.NumberAnimation { duration: 100 loops: QQ2.Animation.Infinite
> target: wheelanimation property: "carspeed" from: 0.0 to: 3000
> running: true }
I don't think this works unless you stop/restart the animation which is not
ideal. A work around is to have a simple NumberAnimation changing a "progress"
value, then in your actual property that you wish to animate, multiply this
progress property by your rotationSpeed property. It requires some extra
gymnastics to cope with non-integer numbers of rotations per cycle of the
progress property.
Something like this should do it (not tested):
Entity {
id: root
property real progress: 0.0
property real rotationSpeed: 10.0
property real angle: previousAngle + ( progress * rotationSpeed )
property real previousAngle: 0.0
function updatePreviousRotation() {
root.previousAngle = root.angle;
}
SequentialAnimation {
running: true
loops: Animation.Infinite
NumberAnimation {
from: 0; to: 1
duration: 1000
}
ScriptAction { script: updatePreviousRotation() }
}
}
This is a limitation of what can be expressed with the Qt Quick 2 animation
framework at present. When we look at adding an animation aspect to Qt 3D for
Qt 5.8 or 5.9, this is one of the things I want to address along with morph
target, key frame and skeletal animations. More likely for 5.9 given we're
already well into the development cycle for 5.8 and we're still putting all
efforts into 5.7.
Hope this helps,
Sean
--
Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK
Klarälvdalens Datakonsult AB, a KDAB Group company
Tel. UK +44 (0)1625 809908, Sweden (HQ) +46-563-540090
KDAB - Qt Experts - Platform-independent software solutions
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