circles

ArrayList<Circle> circles = new ArrayList<Circle>();
int edge = 0, rmin = 10, rmax = 50;
float r = 0, max = 100;

void setup() {
  size(1080, 720);
  circles.add(new Circle(new PVector(width/2, height/2), 20, 0, new PVector(0, 0)));
}

void draw() {
  background(34);
  paintCircles();
  if (circles.size()<max) addCircle();
}

void paintCircles() {
  for (int i=0; i<circles.size(); i++) {
    Circle pc;
    Circle nc;
    Circle c = circles.get(i);
    noFill();
    //stroke(255, 200);
    //fill(255, 100, 200, 150);
    //noStroke();
    strokeWeight(1);
    //ellipse(c.center.x, c.center.y, c.radius*2, c.radius*2);
    if (i>0) {
      pc = circles.get(i-1);
      //ine(pc.center.x, pc.center.y, c.center.x, c.center.y);
      //ellipse(c.in.x, c.in.y, 10, 10);
    }
    if (i<circles.size()-1) {
      nc = circles.get(i+1);
      float angle_in = atan2(c.center.y-c.in.y, c.center.x-c.in.x);
      float angle_out = atan2(c.center.y-nc.in.y, c.center.x-nc.in.x);
      float ai = map(angle_in, -PI, PI, 0, TWO_PI);
      float ao = map(angle_out, -PI, PI, 0, TWO_PI);
      //if (ao < ai) ao += TWO_PI;
      strokeCap(SQUARE);
      //strokeWeight(map(c.radius, 10,50,2,15));
      strokeWeight(2);
      stroke(238);
      noFill();
      //fill(150,0,255,60);
      int num = (int) map(c.radius, rmin, rmax, 1, 5);
      for (int j=0; j<num; j++) {
        float rad = c.radius*map(j, 0, num, 2, 0.5);
        if (i%2==0) {
          if (ao < ai) ao += TWO_PI;
          arc(c.center.x, c.center.y, rad, rad, ai, ao);
        } else {
          if (ai < ao) ai += TWO_PI;
          arc(c.center.x, c.center.y, c.radius*2, c.radius*2, ao, ai);
        }
      }
    }
  }
}

void addCircle() {
  Circle c = circles.get(circles.size()-1);
  r = random(TWO_PI);
  float angle = random(-r, r);
  float radius = random(rmin, rmax);
  float x = c.center.x + cos(angle)*(radius+c.radius);
  float y = c.center.y + sin(angle)*(radius+c.radius);
  PVector v = new PVector(x, y);
  x = c.center.x + cos(angle)*c.radius;
  y = c.center.y + sin(angle)*c.radius;
  PVector in = new PVector(x, y);
  Circle nc = new Circle(v, radius, angle, in);
  if (checkCircles(nc)) {
    circles.add(nc);
  }
}

Boolean checkCircles(Circle c) {
  Boolean outside = true;
  for (int i=0; i<circles.size(); i++) {
    Circle cc = circles.get(i);
    if (c.center.dist(cc.center) < (c.radius + cc.radius)) {
      outside = false;
      return outside;
    }
  }
  return outside;
}

void mouseReleased() {
  addCircle();
  Circle c = circles.get(circles.size()-1);
  println(atan2(c.in.y-c.center.y, c.in.x-c.center.x ));
  println(circles.size());
}

void keyPressed() {
  if (key == 'n') {
    r = 0;
    circles = new ArrayList<Circle>();
    circles.add(new Circle(new PVector(width/2, height/2), 20, 0, new PVector(0, 0)));
  }
  if (key == 's') save(random(9999)+".png");
}

class Circle {

  PVector center;
  PVector in, out;
  float radius;
  float angle;

  Circle(PVector _center, float _radius, float _angle, PVector _in) {
    center = _center;
    radius = _radius;
    angle = _angle;
    in = _in;
  }
}