// Tyler Rigsby, CSE 142
// Does an animation of a ball falling down
import java.awt.*;
import java.util.*;

public class BallDemo {
    public static void main(String[] args) {                
        Scanner console = new Scanner(System.in);
        
        double ball1X = 150.0;
        double ball2X = 350.0;
        double ballY = 50.0;
        
        System.out.print("Enter first ball's initial velocity: ");
        double ball1V0 = console.nextDouble();
        System.out.print("Enter first ball's acceleration: ");
        double ball1A = console.nextDouble();
        
        System.out.print("Enter second ball's initial velocity: ");
        double ball2V0 = console.nextDouble();
        System.out.print("Enter second ball's acceleration: ");
        double ball2A = console.nextDouble();
        
        DrawingPanel panel = new DrawingPanel(500, 500);
        Graphics g = panel.getGraphics();
        panel.setBackground(Color.ORANGE);

        
        for (double t = 0.0; t <= 20.0; t += .05) {
            double ball1Loc = ballY + displacement(ball1A, ball1V0, t);
            g.fillOval((int) ball1X, (int) ball1Loc, 30, 30);
            double ball2Loc = ballY + displacement(ball2A, ball2V0, t);
            g.fillOval((int) ball2X, (int) ball2Loc, 30, 30);
            panel.sleep(50);
            panel.clear();
        }
    }
    
    // Returns the displacement of an object given acceleration a, 
    // initial velocity v0, and time t
    public static double displacement(double a, double v0, double t) {
        return 0.5 * a * t * t + v0 * t;
    }
}