var angle;

function setup() {
  createCanvas(800, 800);
  colorMode(HSB, 100);
}

function draw() {
  background(0);
  
  noFill();
  a = 3;
  b = .25;
  d = 1.8; 

  stars(width/2, height/2, 4);

  angle = PI / 14;

  for (i=0; i<2*PI; i = i+2*PI/13) {
      push();
      stroke(255);
      x = sin(i)*width/sqrt(2) + width/2;
      y = cos(i)*height/sqrt(2) + height/2;
      translate(x*random(0.9,1.1), y*random(0.9,1.1));   
      rotate(-i*random(0.9,1.1));
      branch(90*random(0.6, 1.4), 1);
      pop();
  }

  noLoop();
}

function stars(x, y, size) {
  n_circle = 40;

  var i;
  for (i = 0; i < n_circle; i++) {    
    theta = i*2*PI/11;
    xNew = x + a*exp(b*theta)*cos(theta)*size;
    yNew = y + a*exp(b*theta)*sin(theta)*size;

    stroke(color(i*100/n_circle, 70, 70, 50));

    if (size>d) {
      stars(xNew, yNew, size*0.6);
    }
    else {
      ellipse(xNew, yNew, d, d);
    }
  } 
}
 
function branch(len, generation) {
  // Draw the branch
  strokeWeight(map(generation, 1, 10, 4, .2));
  
  if (len < 3) {
    stroke(color('yellow'));
  }
  line(0, 0, 0, -len);

  // Move to the end and shrink.
  translate(0, -len);
  len *= (.66 * random(0.9, 1.1));
  
  generation++;
  
  if (len > .5) {
    //stroke(240,230,140);
    if (random() <.8) {
      push();
      rotate(angle * random(1, 1.2));
      branch(len, generation);
      pop();
    }

    push();
    rotate(- angle * random(0.8, 1));
    branch(len, generation);
    pop();
  }
}