[Bug] Different behaviour of ShaderEffectSource in emulator vs. device [answered]
asked 2015-02-10 13:55:53 +0300
The following code works fine in Emulator (SDK Beta 1412), changing the gradient of the Rectangle correctly updates the nested ShaderEffectSource and it is reflected on the ShaderEffect which uses it as its texture:
Page {
id: page
SilicaFlickable {
anchors.fill: parent
contentHeight: column.height
Column {
id: column
anchors { top: parent.top; left: parent.left; right: parent.right; leftMargin: Theme.paddingLarge; rightMargin: Theme.paddingLarge; }
spacing: Theme.paddingLarge
PageHeader {
title: qsTr("ShaderEffect Test")
}
Row {
anchors.horizontalCenter: parent.horizontalCenter
spacing: Theme.paddingLarge
Column {
spacing: Theme.paddingSmall
Rectangle {
id: gradientSource
property list<Gradient> gradients: [
Gradient {
GradientStop { position: 0.0; color: "black"; }
GradientStop { position: 1.0; color: "blue"; }
},
Gradient {
GradientStop { position: 0.0; color: "black"; }
GradientStop { position: 1.0; color: "red"; }
}
]
width: 100
height: 100
gradient: gradients[0]
ShaderEffectSource {
id: gradientTexture
anchors.fill: parent
sourceItem: gradientSource
hideSource: false
live: true
}
}
Label {
font.pixelSize: Theme.fontSizeExtraSmall
wrapMode: Text.WordWrap
text: "Rectangle\nShaderEffectSource"
}
}
Column {
spacing: Theme.paddingSmall
ShaderEffect {
property variant source: gradientTexture
width: 100
height: 100
blending: false
cullMode: ShaderEffect.BackFaceCulling
fragmentShader: "
varying highp vec2 qt_TexCoord0;
uniform lowp float qt_Opacity;
uniform sampler2D source;
void main() {
gl_FragColor = texture2D(source, qt_TexCoord0) * qt_Opacity;
}"
}
Label {
font.pixelSize: Theme.fontSizeExtraSmall
text: "ShaderEffect"
}
}
}
Button {
anchors.horizontalCenter: parent.horizontalCenter
text: "Blue gradient"
onClicked: gradientSource.gradient = gradientSource.gradients[0]
}
Button {
anchors.horizontalCenter: parent.horizontalCenter
text: "Red gradient"
onClicked: gradientSource.gradient = gradientSource.gradients[1]
}
}
}
}
It doesn't work on device though (changing Reactangle's gradient doesn't update the ShaderEffectSource).
Un-nesting the ShaderEffectSource from its source item (the Rectangle) works fine both on emulator and on device:
Page {
id: page
SilicaFlickable {
anchors.fill: parent
contentHeight: column.height
Column {
id: column
anchors { top: parent.top; left: parent.left; right: parent.right; leftMargin: Theme.paddingLarge; rightMargin: Theme.paddingLarge; }
spacing: Theme.paddingLarge
PageHeader {
title: qsTr("ShaderEffect Test")
}
Row {
anchors.horizontalCenter: parent.horizontalCenter
spacing: Theme.paddingLarge
Column {
spacing: Theme.paddingSmall
Rectangle {
id: gradientSource
property list<Gradient> gradients: [
Gradient {
GradientStop { position: 0.0; color: "black"; }
GradientStop { position: 1.0; color: "blue"; }
},
Gradient {
GradientStop { position: 0.0; color: "black"; }
GradientStop { position: 1.0; color: "red"; }
}
]
width: 100
height: 100
gradient: gradients[0]
}
Label {
font.pixelSize: Theme.fontSizeExtraSmall
text: "Rectangle"
}
}
Column {
spacing: Theme.paddingSmall
ShaderEffectSource {
id: gradientTexture
width: 100
height: 100
sourceItem: gradientSource
hideSource: false
live: true
}
Label {
font.pixelSize: Theme.fontSizeExtraSmall
text: "ShaderEffectSource"
}
}
Column {
spacing: Theme.paddingSmall
ShaderEffect {
property variant source: gradientTexture
width: 100
height: 100
blending: false
cullMode: ShaderEffect.BackFaceCulling
fragmentShader: "
varying highp vec2 qt_TexCoord0;
uniform lowp float qt_Opacity;
uniform sampler2D source;
void main() {
gl_FragColor = texture2D(source, qt_TexCoord0) * qt_Opacity;
}"
}
Label {
font.pixelSize: Theme.fontSizeExtraSmall
text: "ShaderEffect"
}
}
}
Button {
anchors.horizontalCenter: parent.horizontalCenter
text: "Blue gradient"
onClicked: gradientSource.gradient = gradientSource.gradients[0]
}
Button {
anchors.horizontalCenter: parent.horizontalCenter
text: "Red gradient"
onClicked: gradientSource.gradient = gradientSource.gradients[1]
}
}
}
}
Is it a bug?