#ifdef GL_ES
precision mediump float;
#endif

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

vec2 random2(vec2 st){
    st = vec2( dot(st,vec2(127.1,311.7)),
              dot(st,vec2(269.5,183.3)) );
    return -1.0 + 2.0*fract(sin(st)*43758.5453123);
}

// Value Noise by Inigo Quilez - iq/2013
// https://www.shadertoy.com/view/lsf3WH
float noise(vec2 st) {
    vec2 i = floor(st);
    vec2 f = fract(st);

    vec2 u = f*f*(3.0-2.0*f);

    return mix( mix( dot( random2(i + vec2(0.0,0.0) ), f - vec2(0.0,0.0) ), 
                     dot( random2(i + vec2(1.0,0.0) ), f - vec2(1.0,0.0) ), u.x),
                mix( dot( random2(i + vec2(0.0,1.0) ), f - vec2(0.0,1.0) ), 
                     dot( random2(i + vec2(1.0,1.0) ), f - vec2(1.0,1.0) ), u.x), u.y);
}

float shape(vec2 st, float radius) {
	st = vec2(0.5)-st;
    float r = length(st)*2.0;
    float a = atan(st.y,st.x);
    float m = abs(mod(a,3.14*2.)-3.14)/3.6;
    float f = radius;
    f += (sin(a*20.)*.1*pow(m,2.));
    return 1.-smoothstep(f,f+0.007,r);
}

void main() {
    vec2 st = gl_FragCoord.xy/u_resolution.xy;
    st.x *= u_resolution.x/u_resolution.y;
    vec3 color = vec3(0.0);

    float t = 1.0;
    st += noise(st*2.)*t;
    for (int i = 0; i < 90; i++) {
      st += abs(tan(u_time))+0.05;
   	  color += shape(st, .3);
      color -= shape(st, .27);
      color += smoothstep(0.28, .3,noise(st*10.));
      color -= smoothstep(.35,.4,noise(st*10.));
    }
    gl_FragColor = vec4(1.-color,1.0);
}