[Solved]Question about the example "Scene Graph - OpenGL Under QML"

[stereomatching]

How could I apply the effect on a specific component?

@
//! [1]
import QtQuick 2.0
import OpenGLUnderQML 1.0

Item {

width: 320
height: 480

//! [1] //! [2]
Rectangle {
color: Qt.rgba(1, 1, 1, 0.7)
radius: 10
border.width: 1
border.color: "white"
anchors.fill: label
anchors.margins: -10

   //apply the Squircle effect on the Rectangle rather than the root item 
   Squircle {
        SequentialAnimation on t {
            NumberAnimation { to: 1; duration: 2500; easing.type: Easing.InQuad }
            NumberAnimation { to: 0; duration: 2500; easing.type: Easing.OutQuad }
            loops: Animation.Infinite
            running: true
        }
    }
}

Text {
    id: label
    color: "black"
    wrapMode: Text.WordWrap
    text: "The background here is a squircle rendered with raw OpenGL using the 'beforeRender()' signal in QQuickWindow. This text label and its border is rendered using QML"
    anchors.right: parent.right
    anchors.left: parent.left
    anchors.bottom: parent.bottom
    anchors.margins: 20
}

}
//! [2]

@
No matter how I try, it is always render on the background but not the Rectangle

[sletta]

As the documentation and the description states, the Squircle is not a part of the items rendered by the scene graph. It is using raw OpenGL combined with the QQuickWindow::beforeRendering() signal. It renders itself beneath the entire Qt Quick scene.

If you want to integrate raw GL inside the item scene, have a look at the textureinsgnode example (for integrating raw OpenGL calls using and FBO and a texture) or customgeometry and simplematerial example (for how to create a custom scenegraph node and material.

[stereomatching]

bq. textureinsgnode example, customgeometry, simplematerial

Can't find any example when I input those names in the example
page of QtCreator, are you sure the names are correct?

but I do found other interesting examples which may solve my problem
"Scene Graph-Rendering"

[sletta]

Have a look in the 5.1 qtdeclarative source tree:

http://doc-snapshot.qt-project.org/qt5-stable/qtquick/scenegraph-textureinsgnode.html
http://doc-snapshot.qt-project.org/qt5-stable/qtquick/scenegraph-customgeometry.html
http://doc-snapshot.qt-project.org/qt5-stable/qtquick/scenegraph-simplematerial.html

The "textureinsgnode" example was added for 5.1 but the others have been there since 5.0