Pertemuan 14 : Pong Game

Pertemuan 14 - Pong Game!

Tanggal: 30 November 2025
Nama: Hosea Felix Sanjaya
NRP: 5025241177

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a. Visualisasi Alur di BlueJ

Penjelasan Alur

Diagram di atas menunjukkan alur kerja dan hubungan antar kelas dalam program Pong Game:

• Pong (Controller): Berfungsi sebagai pengendali utama yang mengatur logika permainan, pergerakan bola/paddle, pengecekan tabrakan, dan skor.
• Ball & Paddle (Model): Merupakan objek permainan. Posisi mereka terus diperbarui oleh kelas Pong berdasarkan logika fisika dan input user.
• Renderer (View): Bertugas menampilkan seluruh objek permainan (visual) ke layar.
• Dependensi: Panah menunjukkan bahwa Pong mengontrol Ball dan Paddle, kemudian data posisi dikirim ke Renderer untuk digambar. Pemisahan ini membuat struktur aplikasi lebih modular.

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b. Code dan Penjelasan

1. Class Pong.java

Berperan sebagai pusat pengendali permainan (Game Controller).

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.Timer;

public class Pong implements ActionListener, KeyListener
{
    public static Pong pong;
    public int width = 700, height = 700;
    public Renderer renderer;
    public Paddle player1;
    public Paddle player2;
    public Ball ball;
    public boolean bot = false, selectingDifficulty;
    public boolean w, s, up, down;
    public int gameStatus = 0, scoreLimit = 7, playerWon; //0 = Menu, 1 = Paused, 2 = Playing, 3 = Over
    public int botDifficulty, botMoves, botCooldown = 0;
    public Random random;
    public JFrame jframe;

    public Pong()
    {
        Timer timer = new Timer(20, this);
        random = new Random();
        jframe = new JFrame("Pong");
        renderer = new Renderer();

        jframe.setSize(width + 15, height + 35);
        jframe.setVisible(true);
        jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jframe.add(renderer);
        jframe.addKeyListener(this);

        timer.start();
    }

    public void start()
    {
        gameStatus = 2;
        player1 = new Paddle(this, 1);
        player2 = new Paddle(this, 2);
        ball = new Ball(this);
    }

    public void update()
    {
        if (player1.score >= scoreLimit) { playerWon = 1; gameStatus = 3; }
        if (player2.score >= scoreLimit) { gameStatus = 3; playerWon = 2; }

        if (w) { player1.move(true); }
        if (s) { player1.move(false); }

        if (!bot)
        {
            if (up) { player2.move(true); }
            if (down) { player2.move(false); }
        }
        else
        {
            if (botCooldown > 0) {
                botCooldown--;
                if (botCooldown == 0) { botMoves = 0; }
            }

            if (botMoves < 10)
            {
                if (player2.y + player2.height / 2 < ball.y) { player2.move(false); botMoves++; }
                if (player2.y + player2.height / 2 > ball.y) { player2.move(true); botMoves++; }
                
                if (botDifficulty == 0) botCooldown = 20;
                if (botDifficulty == 1) botCooldown = 15;
                if (botDifficulty == 2) botCooldown = 10;
            }
        }
        ball.update(player1, player2);
    }

    public void render(Graphics2D g)
    {
        g.setColor(Color.BLACK);
        g.fillRect(0, 0, width, height);
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

        if (gameStatus == 0)
        {
            g.setColor(Color.WHITE);
            g.setFont(new Font("Arial", 1, 50));
            g.drawString("PONG", width / 2 - 75, 50);

            if (!selectingDifficulty)
            {
                g.setFont(new Font("Arial", 1, 30));
                g.drawString("Press Space to Play", width / 2 - 150, height / 2 - 25);
                g.drawString("Press Shift to Play with Bot", width / 2 - 200, height / 2 + 25);
                g.drawString("<< Score Limit: " + scoreLimit + " >>", width / 2 - 150, height / 2 + 75);
            }
        }

        if (selectingDifficulty)
        {
            String string = botDifficulty == 0 ? "Easy" : (botDifficulty == 1 ? "Medium" : "Hard");
            g.setFont(new Font("Arial", 1, 30));
            g.drawString("<< Bot Difficulty: " + string + " >>", width / 2 - 180, height / 2 - 25);
            g.drawString("Press Space to Play", width / 2 - 150, height / 2 + 25);
        }

        if (gameStatus == 1)
        {
            g.setColor(Color.WHITE);
            g.setFont(new Font("Arial", 1, 50));
            g.drawString("PAUSED", width / 2 - 103, height / 2 - 25);
        }

        if (gameStatus == 1 || gameStatus == 2)
        {
            g.setColor(Color.WHITE);
            g.setStroke(new BasicStroke(5f));
            g.drawLine(width / 2, 0, width / 2, height);
            g.setStroke(new BasicStroke(2f));
            g.drawOval(width / 2 - 150, height / 2 - 150, 300, 300);
            g.setFont(new Font("Arial", 1, 50));
            g.drawString(String.valueOf(player1.score), width / 2 - 90, 50);
            g.drawString(String.valueOf(player2.score), width / 2 + 65, 50);
            player1.render(g);
            player2.render(g);
            ball.render(g);
        }

        if (gameStatus == 3)
        {
            g.setColor(Color.WHITE);
            g.setFont(new Font("Arial", 1, 50));
            g.drawString("PONG", width / 2 - 75, 50);
            if (bot && playerWon == 2) { g.drawString("The Bot Wins!", width / 2 - 170, 200); }
            else { g.drawString("Player " + playerWon + " Wins!", width / 2 - 165, 200); }
            g.setFont(new Font("Arial", 1, 30));
            g.drawString("Press Space to Play Again", width / 2 - 185, height / 2 - 25);
            g.drawString("Press ESC for Menu", width / 2 - 140, height / 2 + 25);
        }
    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        if (gameStatus == 2) { update(); }
        renderer.repaint();
    }

    public static void main(String[] args) { pong = new Pong(); }

    @Override
    public void keyPressed(KeyEvent e)
    {
        int id = e.getKeyCode();
        if (id == KeyEvent.VK_W) w = true;
        else if (id == KeyEvent.VK_S) s = true;
        else if (id == KeyEvent.VK_UP) up = true;
        else if (id == KeyEvent.VK_DOWN) down = true;
        else if (id == KeyEvent.VK_RIGHT) {
            if (selectingDifficulty) { if (botDifficulty < 2) botDifficulty++; else botDifficulty = 0; }
            else if (gameStatus == 0) scoreLimit++;
        }
        else if (id == KeyEvent.VK_LEFT) {
            if (selectingDifficulty) { if (botDifficulty > 0) botDifficulty--; else botDifficulty = 2; }
            else if (gameStatus == 0 && scoreLimit > 1) scoreLimit--;
        }
        else if (id == KeyEvent.VK_ESCAPE && (gameStatus == 2 || gameStatus == 3)) gameStatus = 0;
        else if (id == KeyEvent.VK_SHIFT && gameStatus == 0) { bot = true; selectingDifficulty = true; }
        else if (id == KeyEvent.VK_SPACE) {
            if (gameStatus == 0 || gameStatus == 3) {
                if (!selectingDifficulty) bot = false; else selectingDifficulty = false;
                start();
            }
            else if (gameStatus == 1) gameStatus = 2;
            else if (gameStatus == 2) gameStatus = 1;
        }
    }

    @Override
    public void keyReleased(KeyEvent e)
    {
        int id = e.getKeyCode();
        if (id == KeyEvent.VK_W) w = false;
        else if (id == KeyEvent.VK_S) s = false;
        else if (id == KeyEvent.VK_UP) up = false;
        else if (id == KeyEvent.VK_DOWN) down = false;
    }

    @Override
    public void keyTyped(KeyEvent e) { }
}

Penjelasan Singkat

• Inisialisasi: Membuat JFrame, Timer (game loop 20ms), dan Renderer.
• Method update(): Menangani logika inti seperti pergerakan paddle (manual & bot), fisika bola, dan kondisi menang/kalah.
• Method render(): Menggambar UI menu, skor, garis lapangan, dan memanggil fungsi render objek lain.
• Input Handling: Menggunakan KeyListener untuk mendeteksi input keyboard (W/S, Arrow Keys, Space, Shift).

2. Class Ball.java

Menangani logika fisik bola, pergerakan, dan pantulan.

import java.awt.Color;
import java.awt.Graphics;
import java.util.Random;

public class Ball
{
    public int x, y, width = 25, height = 25;
    public int motionX, motionY;
    public Random random;
    private Pong pong;
    public int amountOfHits;

    public Ball(Pong pong)
    {
        this.pong = pong;
        this.random = new Random();
        spawn();
    }

    public void update(Paddle paddle1, Paddle paddle2)
    {
        int speed = 5;
        this.x += motionX * speed;
        this.y += motionY * speed;

        if (this.y + height - motionY > pong.height || this.y + motionY < 0)
        {
            if (this.motionY < 0) {
                this.y = 0;
                this.motionY = random.nextInt(4);
                if (motionY == 0) motionY = 1;
            } else {
                this.motionY = -random.nextInt(4);
                this.y = pong.height - height;
                if (motionY == 0) motionY = -1;
            }
        }

        if (checkCollision(paddle1) == 1) {
            this.motionX = 1 + (amountOfHits / 5);
            this.motionY = -2 + random.nextInt(4);
            if (motionY == 0) motionY = 1;
            amountOfHits++;
        }
        else if (checkCollision(paddle2) == 1) {
            this.motionX = -1 - (amountOfHits / 5);
            this.motionY = -2 + random.nextInt(4);
            if (motionY == 0) motionY = 1;
            amountOfHits++;
        }

        if (checkCollision(paddle1) == 2) { paddle2.score++; spawn(); }
        else if (checkCollision(paddle2) == 2) { paddle1.score++; spawn(); }
    }

    public void spawn()
    {
        this.amountOfHits = 0;
        this.x = pong.width / 2 - this.width / 2;
        this.y = pong.height / 2 - this.height / 2;
        this.motionY = -2 + random.nextInt(4);
        if (motionY == 0) motionY = 1;
        if (random.nextBoolean()) motionX = 1; else motionX = -1;
    }

    public int checkCollision(Paddle paddle)
    {
        if (this.x < paddle.x + paddle.width && this.x + width > paddle.x && this.y < paddle.y + paddle.height && this.y + height > paddle.y)
        {
            return 1; //bounce
        }
        else if ((paddle.x > x && paddle.paddleNumber == 1) || (paddle.x < x - width && paddle.paddleNumber == 2))
        {
            return 2; //score
        }
        return 0; //nothing
    }

    public void render(Graphics g)
    {
        g.setColor(Color.WHITE);
        g.fillOval(x, y, width, height);
    }
}

Penjelasan Singkat

• Fisika: Mengatur posisi (x,y) dan arah gerak (motionX, motionY).
• Pantulan: Bola memantul jika mengenai batas atas/bawah layar atau mengenai paddle.
• Skoring: Jika bola melewati paddle, skor lawan bertambah dan posisi bola di-reset (spawn).

3. Class Paddle.java dan Renderer.java

Mengatur objek pemain dan proses penggambaran ke layar.

// PADDLE CLASS
import java.awt.Color;
import java.awt.Graphics;

public class Paddle
{
    public int paddleNumber;
    public int x, y, width = 50, height = 250;
    public int score;

    public Paddle(Pong pong, int paddleNumber)
    {
        this.paddleNumber = paddleNumber;
        if (paddleNumber == 1) this.x = 0;
        if (paddleNumber == 2) this.x = pong.width - width;
        this.y = pong.height / 2 - this.height / 2;
    }

    public void render(Graphics g)
    {
        g.setColor(Color.WHITE);
        g.fillRect(x, y, width, height);
    }

    public void move(boolean up)
    {
        int speed = 15;
        if (up) {
            if (y - speed > 0) y -= speed; else y = 0;
        } else {
            if (y + height + speed < Pong.pong.height) y += speed; else y = Pong.pong.height - height;
        }
    }
}

// RENDERER CLASS
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;

public class Renderer extends JPanel
{
    private static final long serialVersionUID = 1L;

    @Override
    protected void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Pong.pong.render((Graphics2D) g);
    }
}

Penjelasan Singkat

• Paddle: Merepresentasikan pemain kiri (1) atau kanan (2). Method move() membatasi agar paddle tidak keluar layar.
• Renderer: Kelas turunan JPanel yang memanggil method render utama dari kelas Pong setiap kali layar perlu digambar ulang (repaint).

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c. Dokumentasi Output

Tampilan Awal Permainan (Menu)

Tampilan Permainan Selama Berlangsung

Tampilan Saat Salah Satu Pemain Menang

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Kesimpulan

• Aplikasi Pong ini menerapkan konsep Object Oriented Programming (OOP) dengan memisahkan logika permainan (Pong), objek (Ball, Paddle), dan tampilan (Renderer).
• Penggunaan Timer memungkinkan terciptanya game loop yang konsisten untuk memperbarui logika fisika dan animasi.
• Interaksi pengguna ditangani melalui KeyListener, memberikan respons real-time untuk pergerakan paddle.