/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Mobility Components.
**
** $QT_BEGIN_LICENSE:LGPL21$
** 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
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://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 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
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

import QtQuick 2.0

Effect {
    parameters: ListModel {
        ListElement {
            name: "threshold"
            value: 0.5
        }
    }

    // Transform slider values, and bind result to shader uniforms
    property real weight: parameters.get(0).value

    fragmentShaderSrc: "#version 130
                        uniform sampler2D source;
                        uniform float dividerValue;
                        uniform float weight;
                        mat3 G[2] = mat3[](
                            mat3( 1.0, 2.0, 1.0, 0.0, 0.0, 0.0, -1.0, -2.0, -1.0 ),
                            mat3( 1.0, 0.0, -1.0, 2.0, 0.0, -2.0, 1.0, 0.0, -1.0 )
                        );
                        uniform lowp float qt_Opacity;
                        in vec2 qt_TexCoord0;
                        out vec4 FragmentColor;
                        void main() {
                            vec2 uv = qt_TexCoord0.xy;
                            vec4 c = vec4(0.0);
                            if (uv.x < dividerValue) {
                                mat3 intensity;
                                float conv[2];
                                vec3 sample;
                                for (int i=0; i<3; ++i) {
                                    for (int j=0; j<3; ++j) {
                                        sample = texelFetch(source, ivec2(gl_FragCoord) + ivec2(i-1, j-1), 0).rgb;
                                        intensity[i][j] = length(sample) * weight;
                                    }
                                }
                                for (int i=0; i<2; ++i) {
                                    float dp3 = dot(G[i][0], intensity[0]) + dot(G[i][1], intensity[1]) + dot(G[i][2], intensity[2]);
                                    conv[i] = dp3 * dp3;
                                }
                                c = vec4(0.5 * sqrt(conv[0]*conv[0] + conv[1]*conv[1]));
                            } else {
                                c = texture2D(source, qt_TexCoord0);
                            }
                            FragmentColor = qt_Opacity * c;
                        }"
}