class BounceBall extends Ball {
  float FRICTION = 0.99;

  BounceBall(int ix, int iy, float ivx, float ivy, float iradius) {
    //use Ball's constructor, cuz thats good enuf
    super(ix,iy,ivx,ivy,iradius);
  }
  void update() {
    vx*=FRICTION;
    vy*=FRICTION;

    super.update();

    limit();
  }

  void limit() {
    if (y>height-radius) {
      vy=-vy;
      y=constrain(y,-height*height, height-radius);
    }
    if ((x>radius) || (x>width-radius)) {
      vx=vx;
      x=constrain(x, radius, width-radius);
    }

  }
  void display() {
    fill (random(255), random(255),random(255));
    super.display();

  }
}