Particles slow down when mouse is moving

imaqt 0

I have the following QML code:

import QtQuick 2.11
import QtQuick.Controls 2.0
import QtQuick.Particles 2.0

ApplicationWindow {

    // ...
    id: window
    visible: true
    width: 1200
    height: 300
    title: qsTr("Hello World")

    Rectangle{
        id: root
        width: 480; height: 160
        color: "#1f1f1f"

        ParticleSystem{
            id: particleSystem
        }

        Emitter{
            id: emmiter
            anchors.centerIn: parent
            width: 160; height: 80
            system: particleSystem
            emitRate: 10
            lifeSpan: 6400
            lifeSpanVariation: 500
            size: 32
           velocity: TargetDirection{
              targetX: 100
               targetY: 0
                targetVariation: 100/6
                magnitude: 100
            }

        }

        ImageParticle{
            source: "image.png"
            system: particleSystem
            rotation: 15
            rotationVelocity: 45
        }
    }
}

The code runs as expected, but when my move is moving inside the window everything slows down(the movement speed, the rotation speed). Is this expected behaviour and if so how can i disable it?

imaqt 0

Can anyone at least confirm that this issue persists in their device please?

Jake Kirk

Hi @imaqt-0

I do not see the delay/slow down in animation that you are experiencing.

I took your code... (used your imports and more recent import statements). Using your version or this more recent imports did not make a difference:
import QtQuick 2.11
import QtQuick.Controls 2.5
import QtQuick.Particles 2.12

I do not have your "image.png", I therefore added to the project qrc resource "earth.png" & "sun.png" that I found within the Qt samples. Maybe your PNG is different? Much larger?

My laptop is recent (uses the built in Intel 620 graphics chip, I don't think it's anything special)
A Logitech mouse with recent drivers, M310 mouse, etc...

Have you seen this behavior on other hardware?
Maybe it's your video card/software driver?
Or mouse/software. I'd try your code on another device just to see if it's reproducible.

Best,
Jake

imaqt 0

The image isn't important as its reproducible even without it and it's a general problem with any qml animation as far as i can tell. If it doesn't happen on your device it might be a problem with my amd apu.

Jake Kirk

@imaqt-0
I forgot to mentioned that I tested your code on Win10 using the Desktop MSVC2017 64 bit
(community edition of VC2017) as my tool set.
What tools set are you using?

imaqt 0

Win 10 as well, tried with msvc2017 32/64 and mingw 32/64.