blockcanvas.java

Block Application

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;

import com.nec.media.AudioClip;
import com.nec.media.AudioListener;
import com.nec.media.Media;

/**
 * Canvas for block game
 */
public class BlockCanvas extends Canvas implements Runnable, AudioListener {

	// State-related
	private int state; // State
	private final int ACTIVE = 1;
	private final int GAME_OVER = 2;
	private final int CLEAR = 3;

	// Block-related
	private final int BLOCK_H = 7; // Number of horizontal blocks
	private final int BLOCK_V = 5; // Number of vertical blocks
	private final int BLOCK_WIDTH = getWidth() / BLOCK_H;
	private final int BLOCK_HEIGHT = BLOCK_WIDTH / 2;
	private boolean block[][] = new boolean[BLOCK_H][BLOCK_V];
	private int blockCount; // Number of blocks

	// Paddle-related (here referred to as a bar)
	private final int BAR_HEIGHT = 11;
	private final int BAR_WIDTH = 23;
	private int barX = 0;
	private int barY = getHeight() - BAR_HEIGHT;
	private int barMoveX = 0;
	// Ball-related
	private final int BALL_HEIGHT = 10;
	private final int BALL_WIDTH = 10;
	private int ballX;
	private int ballY;
	private int ballMoveX = 5;
	private int ballMoveY = 5;

	private Thread th;

	// Images
	private Image barImg = null;
	private Image ballImg = null;
	private Image blockImg = null;

	// Sounds
	AudioClip bgm; // Background music
	private AudioClip ballSound; // Sound of bouncing ball
	private AudioClip blockSound; // Sound of destroying blocks

	/********************************************
	 * Constructor
	 ********************************************/
	public BlockCanvas() {
		//Loads the audio data
		bgm = Media.getAudioClip("/bgm.mid");
		ballSound = Media.getAudioClip("/ball.mid");
		blockSound = Media.getAudioClip("/block.mid");
		bgm.addAudioListener(this);

		// Loads the images
		try {
			barImg = Image.createImage("/bar.png");
			ballImg = Image.createImage("/ball.png");
			blockImg = Image.createImage("/block.png");
		} catch (Exception e) {
			e.printStackTrace();
		}

		start(); // Starts the game
	}

	/**
	 * Starts the game
	 */
	public void start() {

		// Initializes the ball
		ballX = barX;
		ballY = barY - BALL_HEIGHT;

		// Initializes the blocks
		for (int i = 0; i < BLOCK_H; i++) {
			for (int j = 0; j < BLOCK_V; j++) {
				block[i][j] = true;
			}
		}
		blockCount = BLOCK_H * BLOCK_V;

		// Starts the game
		th = new Thread(this);
		th.start(); // Starts threads
		state = this.ACTIVE; // Sets the state to active
		bgm.play(); // Plays the background music
	}

	/**
	 * Drawing methods
	 */
	protected void paint(Graphics g) {
		// Clears the screen
		g.setColor(255, 255, 255);
		g.fillRect(0, 0, getWidth(), getHeight());

		if (state == ACTIVE) {
			// Block display
			g.setColor(0, 0, 255);
			for (int i = 0; i < BLOCK_H; i++) {
				for (int j = 0; j < BLOCK_V; j++) {
					if (block[i][j]) {
						g.drawImage(
							blockImg,
							i * BLOCK_WIDTH,
							(j + 1) * BLOCK_HEIGHT,
							Graphics.LEFT | Graphics.TOP);
					}
				}
			}

			// Displays the ball
			g.drawImage(ballImg, ballX, ballY, Graphics.LEFT | Graphics.TOP);
			// Displays the paddle
			g.drawImage(barImg, barX, barY, Graphics.LEFT | Graphics.TOP);
		} else if (state == CLEAR) { // Clears the level
			g.setColor(0, 0, 0);
			g.drawString(
				"GAME CLEAR!!!!",
				getWidth() / 2,
				getHeight() / 2,
				Graphics.HCENTER | Graphics.BASELINE);
		} else if (state == GAME_OVER) { // Ends the game
			g.setColor(0, 0, 0);
			g.drawString(
				"GAME OVER....",
				getWidth() / 2,
				getHeight() / 2,
				Graphics.HCENTER | Graphics.BASELINE);
		}
	}

	/**
	 * Operation executed by threads
	 */
	public void run() {

		while (state == ACTIVE) {

			moveBall(); // Moves the ball
			moveBar(); // Moves the paddle
			repaint(); // Repaints them

			try {
				Thread.sleep(50);
			} catch (InterruptedException e) {
				e.printStackTrace();
				break;
			}
		}
	}

	/**
	 // Moves the ball
	 */
	public void moveBall() {
		ballX += ballMoveX;
		ballY += ballMoveY;

		// Bouncing
		// Bounces off a wall
		if (ballX < 0) {
			ballMoveX *= -1;
			ballX = 0;
			// Plays the sound effect
			ballSound.play();
		} else if (getWidth() < ballX + BALL_HEIGHT) {
			ballX = getWidth() - BALL_HEIGHT;
			ballMoveX *= -1;
			// Plays the sound effect
			ballSound.play();
		}
		if (ballY < 0) {
			ballMoveY *= -1;
			ballY = 0;
			// Plays the sound effect
			ballSound.play();
		} else if (ballY > getHeight()) { // If the ball passes through
			// The game ends
			state = GAME_OVER;
		}

		// Bounces off the paddle
		if (ballY + BALL_HEIGHT > barY
			&& ballX + BALL_WIDTH > barX
			&& ballX < barX + BAR_WIDTH) {
			ballMoveY *= -1;
			ballY = barY - BALL_HEIGHT;

			if (barMoveX < 0) {
				ballMoveX -= 2;
			} else if (barMoveX > 0) {
				ballMoveX += 2;
			}

			// Plays the sound effect
			ballSound.play();
		}
		// Hits a block and bounces off
		for (int i = 0; i < BLOCK_H; i++) {
			for (int j = 0; j < BLOCK_V; j++) {
				if (block[i][j]) {
					if (ballX + BALL_WIDTH > i * BLOCK_WIDTH
						&& ballX < (i + 1) * BLOCK_WIDTH) {
						if (ballY + BALL_HEIGHT > (j + 1) * BLOCK_HEIGHT
							&& ballY < (j + 2) * BLOCK_HEIGHT) {
							
							// Clears blocks
							block[i][j] = false;
							blockCount--;
							
							ballMoveY *= -1;
							
							// Plays the sound effect
							blockSound.play();

							// Checks whether or not the level has been cleared
							if (blockCount == 0) {
								state = CLEAR;
							}
						}
					}
				}
			}
		}

	}

	/**
	 * Moves the paddle
	 */
	public void moveBar() {
		barX += barMoveX;

		if (barX < 0) {
			barX = 0;
		} else if (barX + BAR_WIDTH > getWidth()) {
			barX = getWidth() - BAR_WIDTH;
		}
	}

	/*****************************************************
	 * Handling for audio events
	 *****************************************************/
	public void audioAction(AudioClip sound, int event, int param) {
		// Replays the loop
		if (sound == bgm) {
			if (event == AudioListener.AUDIO_COMPLETE) {
				bgm.play();
			}
		}
	}

	/*****************************************
	 * Key event handling
	 *****************************************/
	/**
	 * When a key is pressed
	 */
	protected void keyPressed(int key) {
		if (state == ACTIVE) {
			if (getGameAction(key) == Canvas.RIGHT) {
				barMoveX = 6;
			} else if (getGameAction(key) == Canvas.LEFT) {
				barMoveX = -6;
			}
			repaint();
		} else {
			// Restart
			this.start();
		}
	}

	/**
	 * When a key is released
	 */
	protected void keyReleased(int key) {
		barMoveX = 0;
	}

}