Black screen after existing FullScreen mode - c++

Question

I am trying to make a such thing:
I have a main window with a single button.
After pressing this button two semi transparent windows appear on all screens. They are in a FullScreen mode.
After 4 seconds screens dissapear.
Everything is ok. But when I cklick one of the screens, during process of disappearing, it becomes totaly black. How can I fix it?
// main.qml
import QtQuick 2.10
import QtQuick.Window 2.10
import QtQuick.Controls 2.2
Window {
id: main
visible: true
width: 100
height: 50
title: "Hello Splash World"
Button {
anchors.fill: parent
text: "Show splash"
onClicked: {
for (var i = 0; i < Qt.application.screens.length; ++i) {
var component = Qt.createComponent("SplashScreen.qml");
var window = component.createObject(main, {screen: Qt.application.screens[i]});
window.height = Qt.application.screens[i].height
window.width = Qt.application.screens[i].width
window.showSplash()
}
}
}
}
// SplashScreen.qml
import QtQuick 2.10
import QtQuick.Controls 2.2
ApplicationWindow {
id: splash
flags: Qt.FramelessWindowHint | Qt.WindowStaysOnTopHint | Qt.WA_TranslucentBackground
color: "transparent"
Timer {
running: true
interval: 4000
onTriggered: hideSplash()
}
function showSplash() {
appearAnimation.start()
}
function hideSplash() {
disappearAnumation.start()
}
background: Rectangle {
id: bg
color: "black"
opacity: 0.8
}
SequentialAnimation {
id: appearAnimation
PropertyAction { target: splash; property: "visibility"; value: ApplicationWindow.FullScreen }
NumberAnimation { target: bg; property: "opacity"; duration: 1000; to: 0.8 }
}
SequentialAnimation {
id: disappearAnumation
NumberAnimation { target: bg; property: "opacity"; duration: 2000; to: 0 }
PropertyAction { target: splash; property: "visibility"; value: ApplicationWindow.Hidden }
}
}

Answer 1

I've come across some strange problems with repainting during further development of my program. For example, changing the size of the main form led to black form to. The solution I've found is to use OpenGL for rendering. You can do it by inserting this code:
QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);

Answer 2

Denis Popov answer is correct, but in this mode my application was a bit laggy. Problem wasn't occuring if mode was set to:
QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);
From the other hand this time I was getting following warning in the output everytime I was creating window:
DXGI WARNING: IDXGIFactory::CreateSwapChain: Blt-model swap effects (DXGI_SWAP_EFFECT_DISCARD and DXGI_SWAP_EFFECT_SEQUENTIAL) are legacy swap effects that are predominantly superceded by their flip-model counterparts (DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL and DXGI_SWAP_EFFECT_FLIP_DISCARD). Please consider updating your application to leverage flip-model swap effects to benefit from modern presentation enhancements. More information is available at http://aka.ms/dxgiflipmodel. [ MISCELLANEOUS WARNING #294: ]
Best solution I come up with so far is to run application in debug mode with one flag and in release/deployment with another:
#ifdef QT_DEBUG
QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
#else
QCoreApplication::setAttribute(Qt::AA_UseOpenGLES);
#endif