CurtainEffect.qml Example File

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 import QtQuick 1.0
 import Qt.labs.shaders 1.0

 ShaderEffectItem {
     anchors.fill: parent
     property variant source
     meshResolution: Qt.size(50, 50)

     property real topWidth: width / 2
     property real bottomWidth: width / 2
     property real originalWidth: width
     property real originalHeight: height
     property real amplitude: 0.1

     vertexShader: "
         attribute highp vec4 qt_Vertex;
         attribute highp vec2 qt_MultiTexCoord0;
         uniform highp mat4 qt_ModelViewProjectionMatrix;
         varying highp vec2 qt_TexCoord0;
         varying lowp float shade;

         uniform highp float topWidth;
         uniform highp float bottomWidth;
         uniform highp float originalWidth;
         uniform highp float originalHeight;
         uniform highp float amplitude;

         void main() {
             qt_TexCoord0 = qt_MultiTexCoord0;

             highp vec4 shift = vec4(0, 0, 0, 0);
             shift.x = qt_Vertex.x * ((originalWidth - topWidth) + (topWidth - bottomWidth) * (qt_Vertex.y / originalHeight)) / originalWidth;

             shade = sin(21.9911486 * qt_Vertex.x / originalWidth);
             shift.y = amplitude * (originalWidth - topWidth + (topWidth - bottomWidth) * (qt_Vertex.y / originalHeight)) * shade;

             gl_Position = qt_ModelViewProjectionMatrix * (qt_Vertex - shift);

             shade = 0.2 * (2.0 - shade ) * (1.0 - (bottomWidth + (topWidth  - bottomWidth) * (1.0 - qt_Vertex.y / originalHeight)) / originalWidth);
         }
     "

     fragmentShader: "
         uniform sampler2D source;
         varying highp vec2 qt_TexCoord0;
         varying lowp float shade;
         void main() {
             highp vec4 color = texture2D(source, qt_TexCoord0);
             color.rgb *= 1.0 - shade;
             gl_FragColor = color;
         }
     "
 }