class Hero {
  static final float FRICTION = 0.9;
  static final float MAX_VEL = 1;
  
  float x;
  float y;
  float vx;
  float vy;
  float radius;
  
  
  Hero() {
    x = width / 2;
    y = height / 2;
    radius = 10;
  }
  
  void update() {
    x += vx;
    y += vy;
    vx *= FRICTION;
    vy *= FRICTION;
    
    if (x < 0) {
      // bounce
      x = 0;
      vx *= -1;
    }
    
  }
  
  void render() {
    fill(255, 0, 0);
    noStroke();
    ellipse(x, y, radius * 2, radius * 2);
  }
}