円の中の円

/**
* Circles in Circles
*
* @author aa_debdeb
* @date 2015/10/07
*/

int MAX_DEPTH = 5;
float MAX_RADIAN_SPEED = PI / 64;

Circle root;

void setup(){
  size(500, 500);
  smooth();
  frameRate(24);
  noStroke();
  
  root = new Circle();
}

void draw(){
  colorMode(RGB, 256);
  fill(0);
  background(0);
  root.draw();
  root.update();
}

class Circle{
  float positionRadious;
  float positionRadian;
  float positionRadianSpeed;
  float circleRadious;
  float hue;
  ArrayList<Circle> children;
  int depth;
  
  Circle(){
    positionRadious = sqrt(sq(width) * 2.0) / 2.0;
    positionRadian = PI / 4.0;
    positionRadianSpeed = 0.0;
    circleRadious = width / 2.0;
    depth = 0;
    hue = random(360);
    children = new ArrayList<Circle>();
    makeChildren();
  }
  
  Circle(float positionRadious,float positionRadian, float positionRadianSpeed, int depth){
    this.positionRadious = positionRadious;
    this.positionRadian = positionRadian;
    this.positionRadianSpeed = positionRadianSpeed;
    this.circleRadious = positionRadious;
    this.depth = depth;
    hue = random(360);
    children = new ArrayList<Circle>();
    makeChildren(); 
  }
  
  void makeChildren(){
    if(depth != MAX_DEPTH){
      float nextPositionRadious = circleRadious / 2.0;
      float nextPositionRadian = random(TWO_PI);
      float nextPositionRadianSpeed = random(MAX_RADIAN_SPEED * 2) - MAX_RADIAN_SPEED;
      children.add(new Circle(nextPositionRadious, nextPositionRadian, nextPositionRadianSpeed, depth + 1));
      children.add(new Circle(nextPositionRadious, nextPositionRadian + PI, nextPositionRadianSpeed, depth + 1));
    }
  }
  
  void draw(){
    float x = positionRadious * cos(positionRadian);
    float y = positionRadious * sin(positionRadian);
    colorMode(HSB, 360, 100, 100);
    fill(hue, 100, 100);
    arc(x, y, circleRadious * 2, circleRadious * 2, 0, TWO_PI);
    if(children.size() != 0){
      for(Circle child: children){
        pushMatrix();
        translate(x, y);
        child.draw();
        popMatrix();
      }
    }
  }
  
  void update(){
    positionRadian += positionRadianSpeed;
    if(positionRadian < 0){
      positionRadian += TWO_PI;
    } else if(positionRadian >= TWO_PI){
      positionRadian -= TWO_PI;
    }
    for(Circle child: children){
      child.update();
    }
  }
  
  
}