// Helene Martin, CSE 142
// Simulates two balls falling.

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

public class BallSimulation {
   public static final double ACC_GRAVITY = 9.81;
   
   public static void main(String[] args) {
      Scanner console = new Scanner(System.in);
      
      int ball1x = 20;
      int ball1y = 20;
      System.out.print("Ball 1 v0? ");
      double ball1V0 = console.nextDouble();
      
      int ball2x = 100;
      int ball2y = 10;
      System.out.print("Ball 2 v0? ");
      double ball2V0 = console.nextDouble();
      
      DrawingPanel panel = new DrawingPanel(400, 400);
      Graphics g = panel.getGraphics();
      
      for (double t = 0; t < 10; t += 0.1) {
         panel.clear();
         g.setColor(Color.RED);
         double disp1 = displacement(ball1V0, ACC_GRAVITY, t);
         g.fillOval(ball1x, ball1y + (int) disp1, 40, 40);
         
         g.setColor(Color.BLUE);
         double disp2 = displacement(ball2V0, ACC_GRAVITY, t);
         g.fillOval(ball2x, ball2y + (int) disp2, 40, 40);
         panel.sleep(100);
      }
      
      //System.out.println(displacement(3.0, 4.0, 5.0));
   }
   
   // given an object's initial velocity, acceleration and the current time,
   // calculate and return the displacement.
   public static double displacement(double v0, double a, double t) {
      // v0t + 1/2(at^2)
      return v0 * t + a * Math.pow(t, 2) / 2.0;
   }
}