/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 Nokia Corporation 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
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****************************************************************************/

import QtQuick 2.0
import "internal"

Item {
    id: rootItem
    property variant source
    property variant maskSource
    property real threshold: 0.0
    property real spread: 0.0
    property bool cached: false

    SourceProxy {
        id: sourceProxy
        input: rootItem.source
    }

    SourceProxy {
        id: maskSourceProxy
        input: rootItem.maskSource
    }

    ShaderEffectSource {
         id: cacheItem
         anchors.fill: parent
         visible: rootItem.cached
         smooth: true
         sourceItem: shaderItem
         live: true
         hideSource: visible
     }

    ShaderEffect {
        id: shaderItem
        property variant source: sourceProxy.output
        property variant maskSource: maskSourceProxy.output
        property real threshold: rootItem.threshold
        property real spread: rootItem.spread

        anchors.fill: parent

        fragmentShader: "
            varying highp vec2 qt_TexCoord0;
            uniform highp float qt_Opacity;
            uniform sampler2D source;
            uniform sampler2D maskSource;
            uniform highp float threshold;
            uniform highp float spread;
            void main(void) {
                lowp vec4 colorFragment = texture2D(source, qt_TexCoord0.st);
                lowp vec4 maskFragment = texture2D(maskSource, qt_TexCoord0.st);
                gl_FragColor = colorFragment * smoothstep(threshold * (1.0 + spread) - spread, threshold * (1.0 + spread), maskFragment.a) * qt_Opacity;
            }
        "
    }
}