boolean bounding_box_collision(int b1_x, int b1_y, int b1_w, int b1_h, int b2_x, int b2_y, int b2_w, int b2_h)
	{
	    if ((b1_x > b2_x + b2_w - 1) || // is b1 on the right side of b2?
	        (b1_y > b2_y + b2_h - 1) || // is b1 under b2?
	        (b2_x > b1_x + b1_w - 1) || // is b2 on the right side of b1?
	        (b2_y > b1_y + b1_h - 1))   // is b2 under b1?
	    {
	        // no collision
	        return false;
	    }
	 
	    // collision
	    return true;
	}