#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;

vec2 random2( vec2 p ) {
    return fract(sin(vec2(dot(p,vec2(127.1,311.7)),dot(p,vec2(269.5,183.3))))*43758.5453);
}

void main() {
    vec2 st_ = gl_FragCoord.xy/u_resolution.xy;
    vec2 st = st_;
    st.x *= u_resolution.x/u_resolution.y;

    vec3 color = vec3(.0);

    st *= 50.;

    vec2 i_st = floor(st);
    vec2 f_st = fract(st);

    float m_dist = 1.;
    vec2 m_point = vec2(0.);

    for (int y= -1; y <= 1; y++) {
        for (int x= -1; x <= 1; x++) {
            vec2 neighbor = vec2(float(x),float(y));
            vec2 point = random2(i_st + neighbor);
            point = 0.5 + 0.5*sin(u_time + 6.2831*point);
            vec2 diff = neighbor + point - f_st;
            float dist = length(diff);

            if (dist < m_dist) {
              m_dist = dist;
              m_point = point;
            }
        }
    }

    color += m_dist;

    color.rgb *= vec3(216./255.,203./255.,161./255.) * smoothstep(0.0001, 0.001, m_point.y+0.01);

    float resmin = min(u_resolution.x, u_resolution.y);
    color -=  smoothstep(0.47, 0.5, distance(gl_FragCoord.xy/resmin, (u_resolution/2.)/resmin));

    gl_FragColor = vec4(color,1.0);
}