// Allison Obourn, CSE 142
// Animates two falling balls affected by gravity.
// prompts the user to get their x and y starting positions 
// and starting velocity

import java.awt.*;
import java.util.*;

public class BallSimulation {
	public static void main(String[] args) {
		//System.out.println(displacement(15, 30, 3));

		Scanner console = new Scanner(System.in);
		System.out.print("enter x, y for ball 1: "); // 42 42
		int ball1x = console.nextInt();
		int ball1y = console.nextInt();
		System.out.print("enter velocity for ball 1: ");
		double ball1v0 = console.nextDouble();
		
		System.out.print("enter x, y for ball 2: ");
		int ball2x = console.nextInt();
		int ball2y = console.nextInt();
		System.out.print("enter velocity for ball 2: ");
		double ball2v0 = console.nextDouble();
		
		DrawingPanel p = new DrawingPanel(400, 400);
		Graphics g = p.getGraphics();
		
		for (double t = 1; t <= 10; t += 0.1) {
			double ball1disp = displacement (ball1v0, 9.81, t);
			g.setColor(Color.RED);
			g.fillOval(ball1x, ball1y + (int)ball1disp, 40, 40);
			
			double ball2disp = displacement (ball2v0, 9.81, t);
			g.setColor(Color.BLUE);
			g.fillOval(ball2x, ball2y + (int)ball2disp, 40, 40);
			
			p.sleep(100);
			p.clear();
		}
	}
	
	// Returns 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) {
		double disp = v0 * t + 0.5 * a * Math.pow(t, 2);
		return disp;
	}

}