/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: http://www.qt-project.org/
**
** This file is part of the Qt Mobility Components.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** 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 ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

// Based on http://www.geeks3d.com/20091116/shader-library-2d-shockwave-post-processing-filter-glsl/

uniform float centerX;
uniform float centerY;
uniform float dividerValue;
uniform float granularity;
uniform float time;
uniform float weight;

uniform sampler2D source;
uniform lowp float qt_Opacity;
varying vec2 qt_TexCoord0;

void main()
{
    vec2 uv = qt_TexCoord0.xy;
    vec2 tc = qt_TexCoord0;
    vec2 center = vec2(centerX, centerY);
    const vec3 shock = vec3(10.0, 1.5, 0.1);
    if (uv.x < dividerValue) {
        float distance = distance(uv, center);
        if ((distance <= (time + shock.z)) &&
            (distance >= (time - shock.z))) {
            float diff = (distance - time);
            float powDiff = 1.0 - pow(abs(diff*shock.x), shock.y*weight);
            float diffTime = diff  * powDiff;
            vec2 diffUV = normalize(uv - center);
            tc += (diffUV * diffTime);
        }
    }
    gl_FragColor = qt_Opacity * texture2D(source, tc);
}