What the element is passed in vertextShader and fragmentShader if we don't set ShaderEffectSource

[A Former User]

If we use ShaderEffectItem element without setting ShaderEffectSource element into ShaderEffectItem as property. In the vertextShader and fragmentShader is passed the QML element (as a texture), which is parent of ShaderEffectItem?

@Item {
width: 100; height: 100;
ShaderEffectItem {
anchors.fill: parent
fragmentShader: "
varying highp vec2 qt_TexCoord0;
void main(void)
{
....
}
"
}
@}

Sorry for my bad English