Exercise 55

int _numChildren = 4;
int _maxLevels = 4;
Branch _trunk;
void setup() {
size(750,500);
background(255);
noFill();
smooth();
newTree();
}
void newTree() {
_trunk = new Branch(1, 0, width/2, height/2);
_trunk.drawMe();
}
void draw() {
background(255);
_trunk.updateMe(width/2, height/2);
_trunk.drawMe();
}


class Branch {
  float level, index;
  float x, y;
  float endx, endy;
  float strokeW, alph;
  float len, lenChange;
  float rot, rotChange;

  Branch[] children = new Branch[0];
  Branch(float lev, float ind, float ex, float why) {
    level = lev;
    index = ind;
    strokeW = (1/level) * 10;
    alph = 255 / level;
    len = (1/level) * random(500);
    rot = random(360);
    lenChange = random(10) - 5;
    rotChange = random(10) - 5;
    updateMe(ex, why);
    if (level < _maxLevels) {
      children = new Branch[_numChildren];
      for (int x=0; x < _numChildren; x++) {
        children[x] = new Branch(level+1, x, endx, endy);
      }
    }
  }
  void updateMe(float ex, float why) {
    x = ex;
    y = why;
    rot += rotChange;
    if (rot > 360) { 
      rot = 0;
    } else if (rot < 0) { 
      rot = 360;
    }
    len -= lenChange;
    if (len < 0) { 
      lenChange *= -1;
    } else if (len > 500) { 
      lenChange *= -1;
    }
    float radian = radians(rot);
    endx = x + (len * cos(radian));
    endy = y + (len * sin(radian));
    for (int i=0; i < children.length; i++) { 
        children[i].updateMe(endx, endy);
    }
  }
  void drawMe() {
    if (level > 1) {
      strokeWeight(strokeW);
      stroke(0, alph);
      fill(255, alph);
      line(x, y, endx, endy);
      ellipse(endx, endy, len/12, len/12);
    }
    for (int i=0; i < children.length; i++) {
      children[i].drawMe();
    }
  }
}