uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
varying float vDistance;
varying vec3 vPosition;

float random(in float x) {
    return fract(sin(x) * 1e4);
}

        // Based on Morgan McGuire @morgan3d
        // https://www.shadertoy.com/view/4dS3Wd
float noise(in vec3 p) {
    const vec3 step = vec3(110.0, 241.0, 171.0);

    vec3 i = floor(p);
    vec3 f = fract(p);

            // For performance, compute the base input to a
            // 1D random from the integer part of the
            // argument and the incremental change to the
            // 1D based on the 3D -> 1D wrapping
    float n = dot(i, step);

    vec3 u = f * f * (3.0 - 2.0 * f);
    return mix(mix(mix(random(n + dot(step, vec3(0, 0, 0))), random(n + dot(step, vec3(1, 0, 0))), u.x), mix(random(n + dot(step, vec3(0, 1, 0))), random(n + dot(step, vec3(1, 1, 0))), u.x), u.y), mix(mix(random(n + dot(step, vec3(0, 0, 1))), random(n + dot(step, vec3(1, 0, 1))), u.x), mix(random(n + dot(step, vec3(0, 1, 1))), random(n + dot(step, vec3(1, 1, 1))), u.x), u.y), u.z);
}

//	<https://www.shadertoy.com/view/Xd23Dh>
//	by inigo quilez <http://iquilezles.org/www/articles/voronoise/voronoise.htm>
//

vec3 hash3(vec2 p) {
    vec3 q = vec3(dot(p, vec2(127.1, 311.7)), dot(p, vec2(269.5, 183.3)), dot(p, vec2(419.2, 371.9)));
    return fract(sin(q) * 43758.5453);
}

float iqnoise(in vec2 x, float u, float v) {
    vec2 p = floor(x);
    vec2 f = fract(x);

    float k = 1.0 + 63.0 * pow(1.0 - v, 4.0);

    float va = 0.0;
    float wt = 0.0;
    for(int j = -2; j <= 2; j++) for(int i = -2; i <= 2; i++) {
            vec2 g = vec2(float(i), float(j));
            vec3 o = hash3(p + g) * vec3(u, u, 1.0);
            vec2 r = g - f + o.xy;
            float d = dot(r, r);
            float ww = pow(1.0 - smoothstep(0.0, 1.414, sqrt(d)), k);
            va += o.z * ww;
            wt += ww;
        }

    return va / wt;
}