// Helene Martin, CSE 142
// Animates two falling balls affected by gravity.

import java.awt.*;

public class BallSimulation {
	public static void main(String[] args) {
		DrawingPanel panel = new DrawingPanel(400, 400);
		Graphics g = panel.getGraphics();
			
		//System.out.print(displacement(3.0, 4.0, 5.0)); //returns 65.0
		
		int ball1x = 20;
		int ball1y = 20;
		double ball1V0 = 30;
		
		int ball2x = 100;
		int ball2y = 10;
		double ball2V0 = 40;
		
		for(double t = 1; t <= 10; t += 0.1) {
			double ball1Disp = displacement(ball1V0, 9.81, t);
			g.setColor(Color.RED);
			g.fillOval(ball1x, (int)(ball1y + ball1Disp), 40, 40);
			
			double ball2Disp = displacement(ball2V0, 9.81, t);
			g.setColor(Color.BLUE);
			g.fillOval(ball2x, (int)(ball2y + ball2Disp), 40, 40);		
			
			panel.sleep(100);
			panel.clear();
		}
	}
	
	// Calculates the displacement of an objects starting at velocity v0
	// after t seconds have passed, given an acceleration of a.
	public static double displacement(double v0, double a, double t) {
		return v0 * t + (a / 2) * Math.pow(t, 2);
	}

}