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import QtQuick 2.0

Effect {
    parameters: ListModel {
        ListElement {
            name: "grid spacing"
            value: 0.5
        }
    }

    // Transform slider values, and bind result to shader uniforms
    property real grid: parameters.get(0).value * 10

    property real step_x: 0.0015625
    property real step_y: targetHeight ? (step_x * targetWidth / targetHeight) : 0.0

    fragmentShaderSrc: "uniform float grid;
                        uniform float dividerValue;
                        uniform float step_x;
                        uniform float step_y;

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

                        void main()
                        {
                            vec2 uv = qt_TexCoord0.xy;
                            float offx = floor(uv.x  / (grid * step_x));
                            float offy = floor(uv.y  / (grid * step_y));
                            vec3 res = texture2D(source, vec2(offx * grid * step_x , offy * grid * step_y)).rgb;
                            vec2 prc = fract(uv / vec2(grid * step_x, grid * step_y));
                            vec2 pw = pow(abs(prc - 0.5), vec2(2.0));
                            float  rs = pow(0.45, 2.0);
                            float gr = smoothstep(rs - 0.1, rs + 0.1, pw.x + pw.y);
                            float y = (res.r + res.g + res.b) / 3.0;
                            vec3 ra = res / y;
                            float ls = 0.3;
                            float lb = ceil(y / ls);
                            float lf = ls * lb + 0.3;
                            res = lf * res;
                            vec3 col = mix(res, vec3(0.1, 0.1, 0.1), gr);
                            if (uv.x < dividerValue)
                                gl_FragColor = qt_Opacity * vec4(col, 1.0);
                            else
                                gl_FragColor = qt_Opacity * texture2D(source, uv);
                        }"
}