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# DropShadowEffect.qml Example File

declarative/shadereffects/qml/shadereffects/DropShadowEffect.qml

     /****************************************************************************
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     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
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     ** accordance with the commercial license agreement provided with the
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     ** Alternatively, this file may be used under the terms of the GNU Lesser
     ** General Public License version 2.1 or version 3 as published by the Free
     ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
     ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
     ** following information to ensure the GNU Lesser General Public License
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     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License version 3.0 as published by the Free Software
     ** Foundation and appearing in the file LICENSE.GPL included in the
     ** packaging of this file.  Please review the following information to
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     import QtQuick 1.0
     import Qt.labs.shaders 1.0

     Item {
         id: main
         property real blur: 0.0
         property alias color: shadowEffectWithHBlur.color
         property alias sourceItem: source.sourceItem

         ShaderEffectSource {
             id: source
             smooth: true
             hideSource: false
         }

         ShaderEffectItem {
             id: shadowEffectWithHBlur
             anchors.fill: parent

             property color color: "grey"
             property variant sourceTexture: source;
             property real xStep: main.blur / main.width

             vertexShader:"
                 uniform highp mat4 qt_ModelViewProjectionMatrix;
                 attribute highp vec4 qt_Vertex;
                 attribute highp vec2 qt_MultiTexCoord0;
                 uniform highp float xStep;
                 varying highp vec2 qt_TexCoord0;
                 varying highp vec2 qt_TexCoord1;
                 varying highp vec2 qt_TexCoord2;
                 varying highp vec2 qt_TexCoord4;
                 varying highp vec2 qt_TexCoord5;
                 varying highp vec2 qt_TexCoord6;

                 void main(void)
                 {
                     highp vec2 shift = vec2(xStep, 0.);
                     qt_TexCoord0 = qt_MultiTexCoord0 - 2.5 * shift;
                     qt_TexCoord1 = qt_MultiTexCoord0 - 1.5 * shift;
                     qt_TexCoord2 = qt_MultiTexCoord0 - 0.5 * shift;
                     qt_TexCoord4 = qt_MultiTexCoord0 + 0.5 * shift;
                     qt_TexCoord5 = qt_MultiTexCoord0 + 1.5 * shift;
                     qt_TexCoord6 = qt_MultiTexCoord0 + 2.5 * shift;
                     gl_Position =  qt_ModelViewProjectionMatrix * qt_Vertex;
                 }
             "

             fragmentShader:"
                 uniform highp vec4 color;
                 uniform lowp sampler2D sourceTexture;
                 varying highp vec2 qt_TexCoord0;
                 varying highp vec2 qt_TexCoord1;
                 varying highp vec2 qt_TexCoord2;
                 varying highp vec2 qt_TexCoord4;
                 varying highp vec2 qt_TexCoord5;
                 varying highp vec2 qt_TexCoord6;

                 void main() {
                     highp vec4 sourceColor = (texture2D(sourceTexture, qt_TexCoord0) * 0.1
                     + texture2D(sourceTexture, qt_TexCoord1) * 0.15
                     + texture2D(sourceTexture, qt_TexCoord2) * 0.25
                     + texture2D(sourceTexture, qt_TexCoord4) * 0.25
                     + texture2D(sourceTexture, qt_TexCoord5) * 0.15
                     + texture2D(sourceTexture, qt_TexCoord6) * 0.1);
                     gl_FragColor = mix(vec4(0), color, sourceColor.a);
                 }
             "
         }

         ShaderEffectSource {
             id: hBlurredShadow
             smooth: true
             sourceItem: shadowEffectWithHBlur
             hideSource: true
         }

         ShaderEffectItem {
             id: finalEffect
             anchors.fill: parent

             property color color: "grey"
             property variant sourceTexture: hBlurredShadow;
             property real yStep: main.blur / main.height

             vertexShader:"
                 uniform highp mat4 qt_ModelViewProjectionMatrix;
                 attribute highp vec4 qt_Vertex;
                 attribute highp vec2 qt_MultiTexCoord0;
                 uniform highp float yStep;
                 varying highp vec2 qt_TexCoord0;
                 varying highp vec2 qt_TexCoord1;
                 varying highp vec2 qt_TexCoord2;
                 varying highp vec2 qt_TexCoord4;
                 varying highp vec2 qt_TexCoord5;
                 varying highp vec2 qt_TexCoord6;

                 void main(void)
                 {
                     highp vec2 shift = vec2(0., yStep);
                     qt_TexCoord0 = qt_MultiTexCoord0 - 2.5 * shift;
                     qt_TexCoord1 = qt_MultiTexCoord0 - 1.5 * shift;
                     qt_TexCoord2 = qt_MultiTexCoord0 - 0.5 * shift;
                     qt_TexCoord4 = qt_MultiTexCoord0 + 0.5 * shift;
                     qt_TexCoord5 = qt_MultiTexCoord0 + 1.5 * shift;
                     qt_TexCoord6 = qt_MultiTexCoord0 + 2.5 * shift;
                     gl_Position =  qt_ModelViewProjectionMatrix * qt_Vertex;
                 }
             "

             fragmentShader:"
                 uniform highp vec4 color;
                 uniform lowp sampler2D sourceTexture;
                 uniform highp float qt_Opacity;
                 varying highp vec2 qt_TexCoord0;
                 varying highp vec2 qt_TexCoord1;
                 varying highp vec2 qt_TexCoord2;
                 varying highp vec2 qt_TexCoord4;
                 varying highp vec2 qt_TexCoord5;
                 varying highp vec2 qt_TexCoord6;

                 void main() {
                     highp vec4 sourceColor = (texture2D(sourceTexture, qt_TexCoord0) * 0.1
                     + texture2D(sourceTexture, qt_TexCoord1) * 0.15
                     + texture2D(sourceTexture, qt_TexCoord2) * 0.25
                     + texture2D(sourceTexture, qt_TexCoord4) * 0.25
                     + texture2D(sourceTexture, qt_TexCoord5) * 0.15
                     + texture2D(sourceTexture, qt_TexCoord6) * 0.1);
                     gl_FragColor = sourceColor * qt_Opacity;
                 }
             "
         }
     }