#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);
}

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.);
    return 1.-smoothstep(f,f+0.01,r);
}

float splash(vec2 st) {
   	  return shape(st, .3) - shape(st, .27);
}

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

    st += noise(st*2.);
    for (int i = 0; i < 160; i++) {
      color += splash(st*(random2(vec2(float(i)))*3.));
    }
    color += smoothstep(.3,.31,noise(st*10.));
    
    gl_FragColor = vec4(1.-color,1.0);
}