precision mediump float;

#endif

​

#define PI 3.14159265358979323846

​

​

uniform vec2 u_resolution;

uniform vec2 u_mouse;

uniform float u_time;

uniform float u_zoom;

​

// https://iquilezles.org/articles/distfunctions2d/

float sdCircle( vec2 p, float r )

{

    return length(p) - r;

}

​

/* stripey fun

float random(vec2 st) {

  // vec2 v2_u_time = vec2(1./tan(0.0001*u_time), cos(u_time)*tan(0.0001*u_time));

  vec2 v2_u_time = vec2(log(u_time), 1./log(u_time * u_zoom));

  return fract(sin(dot(st.xy, v2_u_time)) * 

              1.0);

  // return fract(sin(dot(st.xy, vec2(u_mouse.x,  u_mouse.y))) * 

  //             1.0);

}

​

void main() {

  vec2 st = gl_FragCoord.xy/u_resolution.xy;

  float rnd = random(st);

  vec3 _col = step(0.25, vec3(rnd*rnd,fract(1./rnd),2./rnd));

  gl_FragColor = vec4(_col, 1.0);

  // gl_FragColor = vec4(vec3(rnd*rnd,fract(1./rnd),2./rnd), 1.0);

}

*/

​

float random (in vec2 st) {

    return fract(sin(dot(st.xy,

                         vec2(12.9898,78.233)))*

        43758.5453123);

}

​

// Based on Morgan McGuire @morgan3d

// https://www.shadertoy.com/view/4dS3Wd

float noise (in vec2 st) {

    vec2 i = floor(st);

    vec2 f = fract(st);

​

    // Four corners in 2D of a tile

    float a = random(i);

    float b = random(i + vec2(1.0, 0.0));

    float c = random(i + vec2(0.0, 1.0));

    float d = random(i + vec2(1.0, 1.0));

​

    vec2 u = f * f * (3.0 - 2.0 * f);

​

    return mix(a, b, u.x) +

            (c - a)* u.y * (1.0 - u.x) +

            (d - b) * u.x * u.y;

}

​

#define OCTAVES 24

float fbm (in vec2 st) {

    // Initial values

    float value = 0.0;

    float amplitude = .5;

    float frequency = 0.;

    //

    // Loop of octaves

    for (int i = 0; i < OCTAVES; i++) {

        value += amplitude * noise(st);

        st *= 2.; // lacunarity

        amplitude *= .55;

    }

    return value;

}

​

void main() {

    vec2 st = gl_FragCoord.xy/u_resolution.xy;

    st.x *= u_resolution.x/u_resolution.y;

​

    vec3 color = vec3(0.0);

    // color += fbm(st*3.0);//*cos(u_time*0.001));

   // fbm( p + fbm( p + fbm( p ) ) ) 

    vec2 p = vec2(cos(u_time*st));//st * 3.0;

    color += step(0.5,fbm(p*0.01*u_time + fbm(p*u_time + fbm(p*u_time))));

  // color += step(0.55,fbm(p + fbm(p*u_time)));

​

  vec3 pct;

  pct.r = smoothstep(0.0,1.0, pow(st.x,0.25));

  pct.g = 1.;//pow(st.x*PI,2.);

  pct.b = smoothstep(1.0,0.0, st.x);//pow(st.x,0.5);

  color = mix(color, vec3(0,0,0), pct);

  vec2 p2 = (2.0*gl_FragCoord.xy-u_resolution.xy)/u_resolution.y;

  float d = sdCircle(p2, 0.55);

  color = mix( color, pct, 1.0-smoothstep(0.0,0.41,abs(log(12.*cos(u_time*0.01)*d))) );

  // vec2 p3 = (gl_FragCoord.xy - u_resolution.xy) / u_resolution.y;

  // float d2 = sdCircle(p3, 0.55);

  // color = mix( color, pct, 1.0-smoothstep(0.0,0.21,abs(-10.*cos(u_time*0.01)*d2)) );

  // vec2 p4 = (0.25*gl_FragCoord.xy - u_resolution.xy) / u_resolution.y;

  // float d3 = sdCircle(p4, 0.65);

  // color = mix( color, pct, 1.0-smoothstep(0.0,0.81,abs(cos(u_time*0.01)*d3)) );

  // if (sdCircle(p2, 0.5) > 0.45) color = vec3(0.);

  // else

  // else color.r = color.r;

  // bottom-left

  // vec2 bl = step(vec3(0.1),color);

  // // pct = bl.x * bl.y;

    // top-right

    // vec2 tr = step(vec2(0.1),1.0-st);

    // pct *= tr.x * tr.y;

​

  // color = vec3(pct);

    gl_FragColor = vec4(color,0.025);

}

​