/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
**     of its contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 2.0

ShaderEffect {
    property variant source: null;
    property color color: "#ffffff"
    property real blend;

    onSourceChanged: {
        if (source != null) {
            source.setPaintEnabled(false);
        }
    }

    property string vShaderInvertedY: "
    uniform highp mat4 qt_Matrix;
    attribute highp vec4 qt_Vertex;
    attribute highp vec2 qt_MultiTexCoord0;
    varying highp vec2 qt_TexCoord0;
    void main() {
        qt_TexCoord0 = qt_MultiTexCoord0;
        gl_Position = qt_Matrix * qt_Vertex;
    }
    "
    property string vShader: "
    uniform highp mat4 qt_Matrix;
    attribute highp vec4 qt_Vertex;
    attribute highp vec2 qt_MultiTexCoord0;
    varying highp vec2 qt_TexCoord0;
    void main() {
        qt_TexCoord0 = vec2(0, 1) + qt_MultiTexCoord0 * vec2(1, -1);
        gl_Position = qt_Matrix * qt_Vertex;
    }
    "

    vertexShader: source && source.isYInverted ? vShaderInvertedY : vShader

    fragmentShader: "
    uniform lowp sampler2D source;
    uniform highp float qt_Opacity;
    uniform highp vec4 color;
    uniform highp float blend;
    varying highp vec2 qt_TexCoord0;
    void main() {
        highp vec4 sourceColor = texture2D(source, qt_TexCoord0);
        highp vec3 delta = sourceColor.rgb - vec3(0.5);
        highp vec3 lowerContrast = vec3(0.5) + 0.4 * delta;
        gl_FragColor = qt_Opacity * mix(sourceColor, color * sourceColor.a * dot(lowerContrast, vec3(11, 16, 5) * (1. /  32.)), blend);
    }
    "
}