HitBalloonGame.java

HitBalloonGame.java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class HitBalloonGame extends JFrame {
    
    private ShootPanel p = new ShootPanel();
    
    HitBalloonGame() {
        add(p);
        p.setFocusable(true);
    }

    private class ShootPanel extends JPanel {
        
        private int armXDegree = 0;
        
        private boolean isBulletFired = false;
        private int xBullet = 0; 
        private int yBullet = 0;
        private int position = 0;
        private Timer timer = new Timer(100, new TimerListener());
        private int balloonX = 0;
        private int balloonY = 0;
        private boolean isBalloonDrawed = false;
        private boolean isOverlaps = false;
        
        ShootPanel() {
            
            // Add left and right key listeners
            addKeyListener(new KeyAdapter() {
               
               @Override
               public void keyPressed(KeyEvent e) {
                   if (e.getKeyCode() == KeyEvent.VK_LEFT) {
                       if (armXDegree > -40) {
                           armXDegree -= 5;
                           repaint();
                       }
                   } else if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
                       if (armXDegree < 40) {
                           armXDegree += 5;
                           repaint();
                       }
                   } else if (e.getKeyCode() == KeyEvent.VK_UP) {
                       if (!isBulletFired) {
                           position = armXDegree;
                       }
                       isBulletFired = true;
                       timer.start();
                   }
                   
               }
               
            });
        }
        
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            
            // Draw the arm
            Polygon polygon = new Polygon();
            polygon.addPoint(getWidth() / 2, getHeight());
            polygon.addPoint(getWidth() / 2 + 10, getHeight());
            polygon.addPoint(getWidth() / 2 + armXDegree + 10, getHeight() - 40);
            polygon.addPoint(getWidth() / 2 + armXDegree, getHeight() - 40);
            g.fillPolygon(polygon);
            
            if (distance(balloonX, balloonY, getWidth() / 2 + position + xBullet, 
                    getHeight() - 50 + yBullet) <= 20) {
                isOverlaps = true;
            }
            
            // Check if the bullet overlaps with the balloon
            if (isOverlaps) {
                
                g.drawOval(balloonX - 10, balloonY - 10, 20, 20);
                g.drawOval(balloonX + 10, balloonY + 10, 20, 20);
                g.drawOval(balloonX - 15, balloonY - 20, 20, 20);
            } else {
                
                // Draw Bullet if it is fired
                if (isBulletFired) {
                    g.fillOval(getWidth() / 2 + position + xBullet, getHeight() - 50 + yBullet, 10, 10);
                }
                
                // Draw the balloon
                if (!isBalloonDrawed) {
                    balloonX = (int) (Math.random() * getWidth());
                    balloonY = getRandomY(getHeight());
                    isBalloonDrawed = true;
                }
                g.drawOval(balloonX, balloonY, 30, 30);
            }
            
        }
        
        private int distance(int x1, int y1, int x2, int y2) {
            return (int) Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
        }
        
        private int getRandomY(int height) {
            int randomY = (int) (Math.random() * height);
            while (true) {
                if (randomY < height - 80)
                    break;
                randomY = (int) (Math.random() * height);
            }
            
            return randomY;
        }
        
        private class TimerListener implements ActionListener {

            @Override
            public void actionPerformed(ActionEvent e) {
                if (position < 0) {
                    xBullet -= 5;
                } else if (position == 0) {
                    xBullet -= 0;
                } else {
                    xBullet += 5;    
                }
                
                yBullet -= 5;
                
                if (!isOverlaps)
                    repaint();
            }
            
        }
    }
    
    public static void main(String[] args) {
        JFrame frame = new HitBalloonGame();
        frame.setSize(300, 200);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

}