/*{
  "DESCRIPTION": "Layered golden-angle phyllotaxis — counter-rotating sunflower lattices of glowing dots and rings around a bright core.",
  "CREDIT": "claude-opus-4-8",
  "INPUTS": [
    { "NAME": "count",  "TYPE": "float", "DEFAULT": 360.0, "MIN": 60.0, "MAX": 500.0 },
    { "NAME": "spread", "TYPE": "float", "DEFAULT": 0.05, "MIN": 0.02, "MAX": 0.09 },
    { "NAME": "size",   "TYPE": "float", "DEFAULT": 0.03, "MIN": 0.01, "MAX": 0.06 },
    { "NAME": "hue",    "TYPE": "float", "DEFAULT": 0.08, "MIN": 0.0, "MAX": 1.0 }
  ]
}*/

vec3 palette(float t){
  return 0.5 + 0.5 * cos(6.28318 * (t + vec3(0.0, 0.33, 0.67) + hue));
}

void main(){
  vec2 uv = (gl_FragCoord.xy - 0.5 * RENDERSIZE) / RENDERSIZE.y;
  const float GA = 2.39996323;   // golden angle

  vec3 col = vec3(0.0);
  // bright breathing core
  col += palette(0.5 + 0.08 * TIME) * 0.35 * exp(-dot(uv, uv) * 9.0);

  int N = int(count);
  // layer A — filled dots, spiraling clockwise, warm side of palette
  for (int i = 0; i < 500; i++){
    if (i >= N) break;
    float fi = float(i);
    float ang = fi * GA + TIME * 0.3;
    float rad = spread * sqrt(fi);
    vec2 pos = rad * vec2(cos(ang), sin(ang));
    float d = length(uv - pos);
    float s = size * (1.0 - 0.4 * rad);
    float core = smoothstep(s, s * 0.35, d);
    float halo = exp(-d * d / (s * s * 7.0)) * 0.45;
    float phase = fi / count;
    vec3 c = palette(phase + 0.1 * sin(TIME * 0.5 + fi * 0.05));
    float puls = 0.65 + 0.45 * sin(TIME * 2.0 - fi * 0.2);
    col += (core + halo) * c * puls;
  }

  // layer B — finer rings, counter-rotating, offset hue -> depth + interest
  int M = int(count * 0.7);
  for (int i = 0; i < 500; i++){
    if (i >= M) break;
    float fi = float(i);
    float ang = fi * GA - TIME * 0.22 + 1.3;
    float rad = spread * 1.18 * sqrt(fi);
    vec2 pos = rad * vec2(cos(ang), sin(ang));
    float d = length(uv - pos);
    float rr = size * 0.62 * (1.0 - 0.4 * rad);
    float ring = smoothstep(rr * 0.5, 0.0, abs(d - rr)) * 0.8;     // annulus
    vec3 c = palette(0.5 + fi / float(M) + 0.05 * TIME);
    float puls = 0.6 + 0.4 * sin(TIME * 1.6 + fi * 0.15);
    col += ring * c * puls;
  }

  col = col / (1.0 + 0.7 * col);     // tonemap dense overlaps
  col += 0.015;                      // lift blacks a touch
  col = pow(col, vec3(0.82));
  gl_FragColor = vec4(col, 1.0);
}