/*
Copyright (C) 2011 by Ashima Arts (Simplex noise)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

import QtQuick 2.1

ShaderEffect {
    property real time
    NumberAnimation on time {
        loops: Animation.Infinite
        duration: 1000
        from: 30
        to: 200
    }
    vertexShader: "
        uniform highp mat4 qt_Matrix;
        attribute highp vec4 qt_Vertex;
        attribute highp vec2 qt_MultiTexCoord0;
        varying highp vec2 coord;
        void main() {
            coord = qt_MultiTexCoord0;
            gl_Position = qt_Matrix * qt_Vertex;
        }"
    fragmentShader: "
        varying highp vec2 coord;
        uniform lowp float qt_Opacity;
        uniform highp float time;
        uniform lowp float width;
        uniform lowp float height;

        vec3 mod289(vec3 x) {
            return x - floor(x * (1.0 / 289.0)) * 289.0;
        }
        vec2 mod289(vec2 x) {
            return x - floor(x * (1.0 / 289.0)) * 289.0;
        }
        vec3 permute(vec3 x) {
            return mod289(((x*34.0)+1.0)*x);
        }
        float snoise(vec2 v)
        {
            const vec4 C = vec4(0.211324865405187,  // (3.0-sqrt(3.0))/6.0
                                0.366025403784439,  // 0.5*(sqrt(3.0)-1.0)
                               -0.577350269189626,  // -1.0 + 2.0 * C.x
                                0.024390243902439); // 1.0 / 41.0
            // First corner
            vec2 i  = floor(v + dot(v, C.yy) );
            vec2 x0 = v -   i + dot(i, C.xx);

            // Other corners
            vec2 i1;
            //i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
            //i1.y = 1.0 - i1.x;
            i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
            // x0 = x0 - 0.0 + 0.0 * C.xx ;
            // x1 = x0 - i1 + 1.0 * C.xx ;
            // x2 = x0 - 1.0 + 2.0 * C.xx ;
            vec4 x12 = x0.xyxy + C.xxzz;
            x12.xy -= i1;

            // Permutations
            i = mod289(i); // Avoid truncation effects in permutation
            vec3 p = permute( permute( i.y + vec3(0.0, i1.y, 1.0 ))
            + i.x + vec3(0.0, i1.x, 1.0 ));

            vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);
            m = m*m ;
            m = m*m ;

            // Gradients: 41 points uniformly over a line, mapped onto a diamond.
            // The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)
            vec3 x = 2.0 * fract(p * C.www) - 1.0;
            vec3 h = abs(x) - 0.5;
            vec3 ox = floor(x + 0.5);
            vec3 a0 = x - ox;

            // Normalise gradients implicitly by scaling m
            // Approximation of: m *= inversesqrt( a0*a0 + h*h );
            m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );

            // Compute final noise value at P
            vec3 g;
            g.x  = a0.x  * x0.x  + h.x  * x0.y;
            g.yz = a0.yz * x12.xz + h.yz * x12.yw;
            return 130.0 * dot(m, g);
        }

        void main() {
            float n = snoise((coord + vec2(mod(time, 12.12), 0.0)) * (vec2(width, height) / 5.0));
            n = n * 0.6 + 0.4;
            gl_FragColor = vec4(n, n, n, 1.0) * qt_Opacity;
        }"
}