public class PongAnimatedBall {
   public static void main(String[] args) {
       	int WINNER = -1;                            // number of wins
        int UPPER_PDL_xLIM = 16;                    // the boundary the paddle is limited to at the right of the canvas
        int UPPER_PDL_yLIM = 9;                     // the boundary the paddle is limited to at the top
        int LOWER_PDL_xLIM = 0;                     // the boundary the paddle is limited to at the left
        int LOWER_PDL_yLIM = 0;                     // the boundary the paddle is limited to at the bottom
        double PDL_VEL = 0.5;                       // how fast the paddle will move
        double ball_xvel = 0.0032 * (Math.random() < 0.5 ? -1 : 1);    //how fast the ball will move between left and right
        double ball_yvel = 0.0018 * (Math.random() < 0.5 ? -1 : 1);    //how fast the ball will move between top and bottom
	StdDraw.enableDoubleBuffering();

	StdDraw.setXscale(-1.0, 1.0);		//canvas set up
	StdDraw.setYscale(-1.0, 1.0);
	StdDraw.setCanvasSize(600, 600);

	double bpos_x = 300;			// ball position
	double bpos_y = 300;
	double radius = .05;
	StdDraw.setPenRadius(radius);


	double pdl_w = 10.0;			//paddles
 	double pdl_h = 50.0;
	double pdl1_x = 75.0;
	double pdl2_x = 525.0;
	double pdl1_y = 300.0;
	double pdl2_y = 300.0;

	while(WINNER == -1){

		if (Math.abs(bpos_x + ball_xvel) > 1.0 - radius){ ball_xvel = -ball_xvel; }
		if (Math.abs(bpos_y + ball_yvel) > 1.0 - radius){ ball_yvel = -ball_yvel; }

		bpos_x = bpos_x + ball_xvel;
		bpos_y = bpos_y + ball_yvel;

		StdDraw.clear();

		StdDraw.filledCircle(bpos_x, bpos_y, radius);
		StdDraw.filledRectangle(pdl1_x, pdl1_y, pdl_w, pdl_h);
		StdDraw.filledRectangle(pdl2_x, pdl2_y, pdl_w, pdl_h);

		StdDraw.show();
		StdDraw.pause(20);

	}

    }
}