#ifdef GL_ES
    precision mediump float;
#else
#   define lowp
#   define mediump
#   define highp
#endif // GL_ES

uniform lowp float qt_Opacity;
uniform highp float amplitude;
uniform highp float frequency;
uniform highp float time;
uniform sampler2D source;

varying highp vec2 qt_TexCoord0;

void main()
{
    highp vec2 p = sin(time + frequency * qt_TexCoord0);
    gl_FragColor = texture2D(source, qt_TexCoord0 + amplitude * vec2(p.y, -p.x)) * qt_Opacity;
}