#version 100
precision mediump float;
uniform float u_time;
uniform vec2 u_resolution;

void main() {
    vec2 uv = (gl_FragCoord.xy * 2.0 - u_resolution.xy) / u_resolution.y;
    vec2 u0 = uv;
    vec3 finalColor = vec3(0.0);
    
    for (float i = 0.0; i < 4.0; i++) {
        uv = fract(uv * 1.5) - 0.5;
        float d = length(uv) * exp(-length(u0));
        vec3 col = vec3(0.2, 0.5, 0.82);
        d = sin(d * 8.0 + u_time) / 8.0;
        d = abs(d);
        d = pow(0.01 / d, 1.2);
        finalColor += col * d;
    }
    
    gl_FragColor = vec4(finalColor, 1.0);
}