class mass
{
  float px, py, vx, vy, ax, ay, mass, fx, fy;
  void update()
  {
    vx += fx / mass + const_gravityx;
    vy += fy / mass + const_gravityy;
    px += vx;
    py += vy;
    fx = 0;
    fy = 0;
    vx *= const_friction;
    vy *= const_friction;
    if (px < 0)
    {
      px = 0;
      vx *= -const_bounce;
    }
    if (py < 0)
    {
      py = 0;
      vy *= -const_bounce;
    }
    if (px >= width)
    {
      px = width - 1;
      vx *= -const_bounce;
    }
    if (py >= height)
    {
      py = height - 1;
      vy *= -const_bounce;
    }
  }
  
 
 /*
  void mouse() {
    
    
  }
  
  void noMouse() {
    
    
  }
  
  */
}