precision mediump float;

#endif

​

uniform vec2 u_resolution;

uniform float u_time;

​

const int AMOUNT = 7;

​

void main() {

  vec2 coord = 10.0 * (gl_FragCoord.xy - u_resolution / 2.0) / min(u_resolution.y, u_resolution.x);

  float len;

  for (int i = 0; i < AMOUNT; i++) {

    len = length(vec2(coord.x, coord.y));

    coord.x = coord.x - cos(coord.y + sin(len)) + cos(u_time / 9.0);

    coord.y = coord.y + sin(coord.x + cos(len)) + sin(u_time / 12.0);

  }

​

  gl_FragColor = vec4(cos(len * 0.5), cos(len * 0.5), cos(len * 0.52), 1.0);

}