Разработка Легкий эффект искажения воды

<input id="image-selector-input" style="visibility:hidden;" type="file">

<canvas></canvas>

<script type="x-shader/x-fragment" id="vertShader">
    precision mediump float;

    varying vec2 vUv;
    attribute vec2 a_position;

    void main() {
        vUv = .5 * (a_position + 1.);
        gl_Position = vec4(a_position, 0.0, 1.0);
    }
</script>

<script type="x-shader/x-fragment" id="fragShader">
    precision mediump float;

    varying vec2 vUv;
    uniform sampler2D u_image_texture;
    uniform float u_time;
    uniform float u_ratio;
    uniform float u_img_ratio;
    uniform float u_blueish;
    uniform float u_scale;
    uniform float u_illumination;
    uniform float u_surface_distortion;
    uniform float u_water_distortion;

    #define TWO_PI 6.28318530718
    #define PI 3.14159265358979323846

    vec3 mod289(vec3 x) { return x - floor(x * (1. / 289.)) * 289.; }
    vec2 mod289(vec2 x) { return x - floor(x * (1. / 289.)) * 289.; }
    vec3 permute(vec3 x) { return mod289(((x*34.)+1.)*x); }
    float snoise(vec2 v) {
        const vec4 C = vec4(0.211324865405187, 0.366025403784439, -0.577350269189626, 0.024390243902439);
        vec2 i = floor(v + dot(v, C.yy));
        vec2 x0 = v - i + dot(i, C.xx);
        vec2 i1;
        i1 = (x0.x > x0.y) ? vec2(1., 0.) : vec2(0., 1.);
        vec4 x12 = x0.xyxy + C.xxzz;
        x12.xy -= i1;
        i = mod289(i);
        vec3 p = permute(permute(i.y + vec3(0., i1.y, 1.)) + i.x + vec3(0., i1.x, 1.));
        vec3 m = max(0.5 - vec3(dot(x0, x0), dot(x12.xy, x12.xy), dot(x12.zw, x12.zw)), 0.);
        m = m*m;
        m = m*m;
        vec3 x = 2. * fract(p * C.www) - 1.;
        vec3 h = abs(x) - 0.5;
        vec3 ox = floor(x + 0.5);
        vec3 a0 = x - ox;
        m *= 1.79284291400159 - 0.85373472095314 * (a0*a0 + h*h);
        vec3 g;
        g.x = a0.x * x0.x + h.x * x0.y;
        g.yz = a0.yz * x12.xz + h.yz * x12.yw;
        return 130. * dot(m, g);
    }


    mat2 rotate2D(float r) {
        return mat2(cos(r), sin(r), -sin(r), cos(r));
    }

    float surface_noise(vec2 uv, float t, float scale) {
        vec2 n = vec2(.1);
        vec2 N = vec2(.1);
        mat2 m = rotate2D(.5);
        for (int j = 0; j < 10; j++) {
            uv *= m;
            n *= m;
            vec2 q = uv * scale + float(j) + n + (.5 + .5 * float(j)) * (mod(float(j), 2.) - 1.) * t;
            n += sin(q);
            N += cos(q) / scale;
            scale *= 1.2;
        }
        return (N.x + N.y + .1);
    }

    void main() {
        vec2 uv = vUv;
        uv.y = 1. - uv.y;
        uv.x *= u_ratio;

        float t = .002 * u_time;
        vec3 color = vec3(0.);
        float opacity = 0.;

        float outer_noise = snoise((.3 + .1 * sin(t)) * uv + vec2(0., .2 * t));
        vec2 surface_noise_uv = 2. * uv + (outer_noise * .2);

        float surface_noise = surface_noise(surface_noise_uv, t, u_scale);
        surface_noise *= pow(uv.y, .3);
        surface_noise = pow(surface_noise, 2.);

        vec2 img_uv = vUv;
        img_uv -= .5;
        if (u_ratio > u_img_ratio) {
            img_uv.x = img_uv.x * u_ratio / u_img_ratio;
        } else {
            img_uv.y = img_uv.y * u_img_ratio / u_ratio;
        }
        float scale_factor = 1.7;
        img_uv *= scale_factor;
        img_uv += .5;
        img_uv.y = 1. - img_uv.y;

        img_uv += (u_water_distortion * outer_noise);
        img_uv += (u_surface_distortion * surface_noise);

        vec4 img = texture2D(u_image_texture, img_uv);
        img *= (1. + u_illumination * surface_noise);

        color += img.rgb;
        color += u_illumination * vec3(1. - u_blueish, 1., 1.) * surface_noise;
        opacity += img.a;

        float edge_width = .02;
        float edge_alpha = smoothstep(0., edge_width, img_uv.x) * smoothstep(1., 1. - edge_width, img_uv.x);
        edge_alpha *= smoothstep(0., edge_width, img_uv.y) * smoothstep(1., 1. - edge_width, img_uv.y);
        color *= edge_alpha;
        opacity *= edge_alpha;

        gl_FragColor = vec4(color, opacity);
    }
</script>