big_slow.glsl

vec3 hsv2rgb(vec3 c) {
    vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
    return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

float rand(vec2 co){
    return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
}

vec4 get_color(vec2 p) {
  vec4 sum;
  const int blobs = 64;
  for (int i = 0; i < blobs; ++i) {
    float scale = 1.0;
    float period = 1000.0 + float(i) * 297.2;
    period *= scale;
    float w = mod(iFrame, period) / period;
    w += float(i) / float(blobs);
    float angle = w * 6.28318530717958647693;
    float period2 = 1000.0 + float(i) * 230.7;
    period2 *= scale;
    float w2 = mod(iFrame, period2) / period2;
    w2 -= float(i) / float(blobs);
    float angle2 = w2 * 6.28318530717958647693;
    
    vec2 ce = 40.0 * vec2(cos(angle), sin(angle2));
    float dist = sqrt(pow(p.x - ce.x,2.0) + pow(p.y - ce.y, 2.0));
    vec3 color = hsv2rgb(vec3(30.1428 * float(i)/float(blobs), 1.0, 1.0));
    
    float max_alpha = 0.3;
    vec4 col4;
    
    float size = 3.0 + 8.0 * rand(vec2(period, period2));
    float fade_size = 0.5 * size;
    if (dist < size - fade_size) {
      sum += vec4(color, max_alpha);
    } else if (dist < size) {
      float fade_level = 1.0 - (dist - size + fade_size) / fade_size;
      float fade_pixel = (6.28 * fade_level - sin(6.28 * fade_level)) / 6.28;
      sum += vec4(color * fade_pixel, fade_pixel * max_alpha);
    }
  }
  return sum;
}