/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
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** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
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** $QT_END_LICENSE$
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****************************************************************************/

import QtQuick 2.0
import QtGraphicalEffects.private 1.0

Item {
    id: rootItem
    property variant source
    property variant maskSource
    property real blur: 0.0
    property bool transparentBorder: false
    property bool cached: false

    SourceProxy {
        id: sourceProxy
        input: rootItem.source
    }

    SourceProxy {
        id: maskSourceProxy
        input: rootItem.maskSource
    }

    ShaderEffectSource {
        id: cacheItem
        anchors.fill: shaderItem
        visible: rootItem.cached
        sourceItem: shaderItem
        live: true
        hideSource: visible
        smooth: rootItem.blur > 0
    }

    property string __internalBlurVertexShader: "
        attribute highp vec4 qt_Vertex;
        attribute highp vec2 qt_MultiTexCoord0;
        uniform highp mat4 qt_Matrix;
        uniform highp float yStep;
        uniform highp float xStep;
        varying highp vec2 qt_TexCoord0;
        varying highp vec2 qt_TexCoord1;
        varying highp vec2 qt_TexCoord2;
        varying highp vec2 qt_TexCoord3;

        void main() {
            qt_TexCoord0 = vec2(qt_MultiTexCoord0.x + xStep, qt_MultiTexCoord0.y + yStep * 0.36);
            qt_TexCoord1 = vec2(qt_MultiTexCoord0.x + xStep * 0.36, qt_MultiTexCoord0.y - yStep);
            qt_TexCoord2 = vec2(qt_MultiTexCoord0.x - xStep * 0.36, qt_MultiTexCoord0.y + yStep);
            qt_TexCoord3 = vec2(qt_MultiTexCoord0.x - xStep, qt_MultiTexCoord0.y - yStep * 0.36);
            gl_Position = qt_Matrix * qt_Vertex;
        }
    "

    property string __internalBlurFragmentShader: "
        uniform lowp sampler2D source;
        uniform lowp float qt_Opacity;
        varying highp vec2 qt_TexCoord0;
        varying highp vec2 qt_TexCoord1;
        varying highp vec2 qt_TexCoord2;
        varying highp vec2 qt_TexCoord3;

        void main() {
            highp vec4 sourceColor = (texture2D(source, qt_TexCoord0) +
            texture2D(source, qt_TexCoord1) +
            texture2D(source, qt_TexCoord2) +
            texture2D(source, qt_TexCoord3)) * 0.25;
            gl_FragColor = sourceColor * qt_Opacity;
        }
   "

    ShaderEffect {
        id: mask0
        property variant source: maskSourceProxy.output
        anchors.fill: parent
        visible: false
        smooth: true
    }

   ShaderEffectSource {
       id: masklevel1
       width: Math.ceil(shaderItem.width / 32) * 32
       height: Math.ceil(shaderItem.height / 32) * 32
       sourceItem: mask0
       hideSource: rootItem.visible
       sourceRect: transparentBorder ? Qt.rect(-64, -64, shaderItem.width, shaderItem.height) : Qt.rect(0, 0, 0, 0)
       visible: false
       smooth: rootItem.blur > 0
   }

    ShaderEffect {
        id: level0
        property variant source: sourceProxy.output
        anchors.fill: parent
        visible: false
        smooth: true
    }

    ShaderEffectSource {
        id: level1
        width: Math.ceil(shaderItem.width / 32) * 32
        height: Math.ceil(shaderItem.height / 32) * 32
        sourceItem: level0
        hideSource: rootItem.visible
        sourceRect: transparentBorder ? Qt.rect(-64, -64, shaderItem.width, shaderItem.height) : Qt.rect(0, 0, 0, 0)
        visible: false
        smooth: rootItem.blur > 0
    }

    ShaderEffect {
        id: effect1
        property variant source: level1
        property real yStep: 1/height
        property real xStep: 1/width
        anchors.fill: level2
        visible: false
        smooth: true
        vertexShader: __internalBlurVertexShader
        fragmentShader: __internalBlurFragmentShader
    }

    ShaderEffectSource {
        id: level2
        width: level1.width / 2
        height: level1.height / 2
        sourceItem: effect1
        hideSource: rootItem.visible
        visible: false
        smooth: true
    }

    ShaderEffect {
        id: effect2
        property variant source: level2
        property real yStep: 1/height
        property real xStep: 1/width
        anchors.fill: level3
        visible: false
        smooth: true
        vertexShader: __internalBlurVertexShader
        fragmentShader: __internalBlurFragmentShader
    }

    ShaderEffectSource {
        id: level3
        width: level2.width / 2
        height: level2.height / 2
        sourceItem: effect2
        hideSource: rootItem.visible
        visible: false
        smooth: true
    }

    ShaderEffect {
        id: effect3
        property variant source: level3
        property real yStep: 1/height
        property real xStep: 1/width
        anchors.fill: level4
        visible: false
        smooth: true
        vertexShader: __internalBlurVertexShader
        fragmentShader: __internalBlurFragmentShader
    }

    ShaderEffectSource {
        id: level4
        width: level3.width / 2
        height: level3.height / 2
        sourceItem: effect3
        hideSource: rootItem.visible
        visible: false
        smooth: true
    }

    ShaderEffect {
        id: effect4
        property variant source: level4
        property real yStep: 1/height
        property real xStep: 1/width
        anchors.fill: level5
        visible: false
        smooth: true
        vertexShader: __internalBlurVertexShader
        fragmentShader: __internalBlurFragmentShader
    }

    ShaderEffectSource {
        id: level5
        width: level4.width / 2
        height: level4.height / 2
        sourceItem: effect4
        hideSource: rootItem.visible
        visible: false
        smooth: true
    }

    ShaderEffect {
        id: effect5
        property variant source: level5
        property real yStep: 1/height
        property real xStep: 1/width
        anchors.fill: level6
        visible: false
        smooth: true
        vertexShader: __internalBlurVertexShader
        fragmentShader: __internalBlurFragmentShader
    }

    ShaderEffectSource {
        id: level6
        width: level5.width / 2
        height: level5.height / 2
        sourceItem: effect5
        hideSource: rootItem.visible
        visible: false
        smooth: true
    }

    ShaderEffect {
        id: shaderItem
        property variant mask: masklevel1
        property variant source1: level1
        property variant source2: level2
        property variant source3: level3
        property variant source4: level4
        property variant source5: level5
        property variant source6: level6
        property real lod: Math.sqrt(rootItem.blur) * 1.2 - 0.2
        property real weight1
        property real weight2
        property real weight3
        property real weight4
        property real weight5
        property real weight6

        x: transparentBorder ? -64 : 0
        y: transparentBorder ? -64 : 0
        width: transparentBorder ? parent.width + 128 : parent.width
        height: transparentBorder ? parent.height + 128 : parent.height

        fragmentShader: "
            uniform lowp sampler2D mask;
            uniform lowp sampler2D source1;
            uniform lowp sampler2D source2;
            uniform lowp sampler2D source3;
            uniform lowp sampler2D source4;
            uniform lowp sampler2D source5;
            uniform lowp sampler2D source6;
            uniform lowp float lod;
            uniform lowp float qt_Opacity;
            varying mediump vec2 qt_TexCoord0;

            mediump float weight(mediump float v) {
                if (v <= 0.0)
                    return 1.0;

                if (v >= 0.5)
                    return 0.0;

                return 1.0 - v * 2.0;
            }

            void main() {

                lowp vec4 maskColor = texture2D(mask, qt_TexCoord0);
                mediump float l = lod * maskColor.a;

                mediump float w1 = weight(abs(l - 0.100));
                mediump float w2 = weight(abs(l - 0.300));
                mediump float w3 = weight(abs(l - 0.500));
                mediump float w4 = weight(abs(l - 0.700));
                mediump float w5 = weight(abs(l - 0.900));
                mediump float w6 = weight(abs(l - 1.100));

                mediump float sum = w1 + w2 + w3 + w4 + w5 + w6;
                mediump float weight1 = w1 / sum;
                mediump float weight2 = w2 / sum;
                mediump float weight3 = w3 / sum;
                mediump float weight4 = w4 / sum;
                mediump float weight5 = w5 / sum;
                mediump float weight6 = w6 / sum;

                lowp vec4 sourceColor = texture2D(source1, qt_TexCoord0) * weight1;
                sourceColor += texture2D(source2, qt_TexCoord0) * weight2;
                sourceColor += texture2D(source3, qt_TexCoord0) * weight3;
                sourceColor += texture2D(source4, qt_TexCoord0) * weight4;
                sourceColor += texture2D(source5, qt_TexCoord0) * weight5;
                sourceColor += texture2D(source6, qt_TexCoord0) * weight6;

                gl_FragColor = sourceColor * qt_Opacity;

            }
        "
    }
}