I am almost done with my first little java game for my final project. It is a sidescroller where you have to shoot/avoid asteroids. My last problem is figuring out how to make my array of asteroids collide with the player's lasers. Here's what I have so far, there's an "AWT-EventQueue-0" java.lang.NullPointerException" on line 137, that I can't deal with. Any help is appreciated.
Edit: I added in my other classes, I realize it would be hard to judge the functionality of my code if I didn't show you where it came from.
package ShooterGame;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.*;
public class Board extends JPanel implements ActionListener
{
Enemy[] baddies = new Enemy[10000];
Player p;
Image img;
int y;
Timer time;
boolean lost = false;
static Font font = new Font("SanSerif", Font.BOLD, 24);
public AudioClip theme, bang, laser;
static ArrayList<Enemy> enemies;
public static int score = 0;
public static int lives = 5;
public Board()
{
p = new Player();
addKeyListener(new ActionListener());
setFocusable(true);
ImageIcon i = new ImageIcon("images/background.png");
img = i.getImage();
time = new Timer(5, this);
time.start();
for(int j = 0; j < baddies.length; j++)
{
Random ran = new Random();
y = ran.nextInt(365)+1;
baddies[j]= new Enemy((100*j + 700), y, "images/asteroid.gif");
}
theme = Applet.newAudioClip(getClass().getResource("theme.mid"));
theme.play();
bang = Applet.newAudioClip(getClass().getResource("bang.wav"));
}
public void actionPerformed(ActionEvent e)
{
checkCollisions();
ArrayList<?> bullets = Player.getBullets();
for(int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet)bullets.get(i);
if(b.isVisible() == true)
{
b.move();
}
else
{
bullets.remove(i);
}
}
p.move();
for(int i = 0; i < baddies.length; i++)
{
if(p.x > 400)
{
baddies[i].move(p.getdx());
}
}
repaint();
}
public void paint(Graphics g)
{
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
if(lost)
{
g2d.drawString("You Lose!", 300, 300);
}
if((p.getX() - 590) % 2400 == 0 || (p.getX() - 590) % 2400 == 1)
{
p.nx = 0;
}
if((p.getX() - 1790) % 2400 == 0 ||(p.getX() - 1790) % 2400 == 1)
{
p.nx2 = 0;
}
g2d.drawImage(img, 685-p.nx2, 0, null);
if(p.getX() >= 590)
{
g2d.drawImage(img, 685-p.nx, 0, null);
}
g2d.drawImage(p.getImage(), p.edge, p.getY(), null);
ArrayList<?> bullets = Player.getBullets();
for(int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet)bullets.get(i);
g2d.drawImage(b.getImg(), b.getX(), b.getY(), null);
}
for(int i = 0; i < baddies.length; i++)
{
if(baddies[i].isAlive == true)
{
g2d.drawImage(baddies[i].getImg(), baddies[i].getX(), baddies[i].getY(), null);
}
}
g2d.setColor(Color.white);
g2d.drawString("Score: " + score, 0, 320);
g2d.drawString("Lives: " + lives, 80, 320);
}
public void checkCollisions()
{
Rectangle[] rect = new Rectangle[baddies.length];
for(int i = 0; i < baddies.length; i++)
{
Enemy e = (Enemy)baddies[i];
rect[i] = e.getBounds();
}
ArrayList<?> bullets = Player.getBullets();
for (int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet) bullets.get(i);
Rectangle b1 = b.getBounds();
if (rect[i].intersects(b1) && baddies[i].isAlive())
{
score++;
baddies[i].isAlive = false;
baddies[i].isVisible = false;
bang.play();
}
Rectangle h = p.getBounds();
if (h.intersects(rect[i]))
{
if(baddies[i].isAlive() == true)
{
lives--;
if(lives < 0)
{
lost = true;
theme.stop();
System.exit(1);
}
}
}
}
}
private class ActionListener extends KeyAdapter
{
public void keyReleased(KeyEvent e)
{
p.keyReleased(e);
}
public void keyPressed(KeyEvent e)
{
p.keyPressed(e);
}
}
}
Enemy
package ShooterGame;
import java.awt.*;
import javax.swing.ImageIcon;
public class Enemy
{
int x, y;
Image img;
boolean isAlive = true;
boolean isVisible = true;
public Enemy(int startX, int startY, String location)
{
x = startX;
y = startY;
ImageIcon l = new ImageIcon(location);
img = l.getImage();
}
public Rectangle getBounds()
{
return new Rectangle(x, y, 60, 60);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public boolean isAlive()
{
return isAlive;
}
public boolean isVisible()
{
return isVisible;
}
public Image getImg()
{
return img;
}
public void move(int dx)
{
x = x - dx;
}
}
Bullet
package ShooterGame;
import java.applet.Applet;
import java.awt.*;
import javax.swing.ImageIcon;
import java.applet.AudioClip;
public class Bullet
{
int x, y;
Image img;
boolean visible;
public Bullet(int startX, int startY)
{
x = startX;
y = startY;
ImageIcon newBullet = new ImageIcon("images/bullet.gif");
img = newBullet.getImage();
visible = true;
}
public Rectangle getBounds()
{
return new Rectangle(x, y, 9, 5);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public Image getImg()
{
return img;
}
public boolean isVisible()
{
return visible;
}
public void move()
{
x = x + 2;
if(x > 700)
{
visible = false;
}
}
public void setVisible(boolean isVisible)
{
visible = isVisible;
}
}
Player
package ShooterGame;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import javax.swing.ImageIcon;
public class Player
{
int x, dx, y, dy, nx2, nx, edge, ceiling;
Image player;
ImageIcon ib = new ImageIcon("images/player1back.gif");
ImageIcon i = new ImageIcon("images/playerstill.gif");
ImageIcon f = new ImageIcon("images/playerforward.gif");
ImageIcon up = new ImageIcon("images/playerup.gif");
ImageIcon down = new ImageIcon("images/playerdown.gif");
public AudioClip laser;
static ArrayList<Bullet> bullets;
public Player()
{laser = Applet.newAudioClip(getClass().getResource("laser.wav"));
player = ib.getImage();
x = 75;
nx = 0;
nx2 = 685;
y = 172;
edge = 150;
ceiling = 0;
bullets = new ArrayList<Bullet>();
}
public static ArrayList<Bullet> getBullets()
{
return bullets;
}
public void fire()
{
Bullet z = new Bullet((edge + 60), (y+17));
bullets.add(z);
}
public Rectangle getBounds()
{
return new Rectangle(edge, y, 43, 39);
}
public void move()
{
y = y + dy;
if(y < ceiling)
{
y = ceiling;
}
if(y > 290)
{
y = 290;
}
if(dx != -1)
{
if(edge + dx <= 151)
{
edge = edge + dx;
}
else
{
x = x + dx;
nx2 = nx2 + dx;
nx = nx + dx;
}
}
else
{
if(edge + dx > 0)
{
edge = edge + dx;
}
}
}
public int getX()
{
return x;
}
public int getdx()
{
return dx;
}
public int getY()
{
return y;
}
public Image getImage()
{
return player;
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT)
{
dx = 2;
player = f.getImage();
}
if(key == KeyEvent.VK_UP)
{
dy = -1;
player = up.getImage();
}
if(key == KeyEvent.VK_DOWN)
{
dy = 1;
player = down.getImage();
}
if(key == KeyEvent.VK_SPACE)
{
fire();
laser.play();
}
}
public void keyReleased(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT)
{
dx = 1;
player = ib.getImage();
}
if(key == KeyEvent.VK_UP)
{
dy = 0;
player = ib.getImage();
}
if(key == KeyEvent.VK_DOWN)
{
dy = 0;
player = ib.getImage();
}
}
}
Frame
package ShooterGame;
import javax.swing.*;
public class Frame
{
public AudioClip theme;
public Frame()
{
JFrame frame = new JFrame();
frame.add(new Board());
frame.setTitle("SideShooter");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(700,365);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
public static void main(String[] args)
{
new Frame();
}
}
Ok, so the problem is the line mentioned in the other answer, but I believe it is that all the enemies may not be initialised before it checks collisions. Because you are making 10000 of them to start with, I think your action performed method may be checking collisions before they have all be created.
One thing to try could be to bring down the amount of enemies you have and see if it still keeps happening, try 100 or 1000, but this still won't fix the issue.
You really want to be change your game to run in it's own loop though, at the moment you are only checking collisions when the player performs an action. so if the player stops moving, no collision detection...
I would suggest that you find a book called 'Killer Game Programming in Java', there are free ebook version, and just read the first 2 chapters about making a game loop. The book is a bit old, but the basics of the loop are very good.
This question here also contains a very simple loop, and some suggestions in the comments about how to make it better.
The error is on the line
rect[i] = e.getBounds();
Are you not initializing the bounds of your Enemy class correctly? Alternatively, the Enemy you pulled out of the array could be null.
Related
Look I'm going to be up front about this. My assignment is due soon and i've spent way too many hours trying to fix this problem with no success at all. I'm essentially clueless at what the issue is and I really dont know where to look. I have 5 classes, I will try and post them all to ensure I get the answer, I am unable to change GameManager or Goal but I am allowed to change any other class.
The problem lines are this.canvasGraphics.drawImage(player.getCurrentImage() where drawImage says it isnt applicable for the arguments
and
this.enemies[i].getX() - (this.enemies[i].getCurrentImage().getWidth() / 2),
this.enemies[i].getY() - (this.enemies[i].getCurrentImage().getHeight() / 2), null);
where getWidth and getHeight show an almost identical error
thanks in advance
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferedImage;
import java.awt.Font;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class GameManager extends JFrame implements KeyListener {
private int canvasWidth;
private int canvasHeight;
private int borderLeft;
private int borderTop;
private BufferedImage canvas;
private Stage stage;
private Enemy[] enemies;
private Player player;
private Goal goal;
private Graphics gameGraphics;
private Graphics canvasGraphics;
private int numEnemies;
private boolean continueGame;
public static void main(String[] args) {
// During development, you can adjust the values provided in the brackets below
// as needed. However, your code must work with different/valid combinations
// of values.
int choice;
do{
GameManager managerObj = new GameManager(1920, 1080);
choice=JOptionPane.showConfirmDialog(null,"Play again?", "", JOptionPane.OK_CANCEL_OPTION);
}while(choice==JOptionPane.OK_OPTION);
System.exit(0);
}
public GameManager(int preferredWidth, int preferredHeight) {
int maxEnemies;
try{
maxEnemies=Integer.parseInt(JOptionPane.showInputDialog("How many enemies? (Default is 5)"));
if (maxEnemies<0)
maxEnemies=5;
}
catch (Exception e){
maxEnemies=5;
}
this.borderLeft = getInsets().left;
this.borderTop = getInsets().top;
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
if (screenSize.width < preferredWidth)
this.canvasWidth = screenSize.width - getInsets().left - getInsets().right;
else
this.canvasWidth = preferredWidth - getInsets().left - getInsets().right;
if (screenSize.height < preferredHeight)
this.canvasHeight = screenSize.height - getInsets().top - getInsets().bottom;
else
this.canvasHeight = preferredHeight - getInsets().top - getInsets().bottom;
setSize(this.canvasWidth, this.canvasHeight);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
addKeyListener(this);
Random rng = new Random();
this.canvas = new BufferedImage(this.canvasWidth, this.canvasHeight, BufferedImage.TYPE_INT_RGB);
// Create a Stage object to hold the background images
this.stage = new Stage();
// Create a Goal object with its initial x and y coordinates
this.goal = new Goal((Math.abs(rng.nextInt()) % (this.canvasWidth)),
(Math.abs(rng.nextInt()) % this.canvasHeight));
// Create a Player object with its initial x and y coordinates
this.player = new Player((Math.abs(rng.nextInt()) % (this.canvasWidth)),
(Math.abs(rng.nextInt()) % this.canvasHeight));
// Create the Enemy objects, each with a reference to this (GameManager) object
// and their initial x and y coordinates.
this.numEnemies = maxEnemies;
this.enemies = new Enemy[this.numEnemies];
for (int i = 0; i < this.numEnemies; i++) {
this.enemies[i] = new Enemy(this, Math.abs(rng.nextInt()) % (this.canvasWidth),
Math.abs(rng.nextInt()) % this.canvasHeight);
}
this.gameGraphics = getGraphics();
this.canvasGraphics = this.canvas.getGraphics();
this.continueGame = true;
long gameStartTime=System.nanoTime();
while (this.continueGame) {
updateCanvas();
}
this.stage.setGameOverBackground();
double gameTime=(System.nanoTime()-gameStartTime)/1000000000.0;
updateCanvas();
this.gameGraphics.setFont(new Font(this.gameGraphics.getFont().getFontName(), Font.PLAIN, 50));
if (gameTime<1)
this.gameGraphics.drawString("Oops! Better luck next time...", this.canvasWidth/3, this.canvasHeight/2 - 50);
else
this.gameGraphics.drawString("You survived " + String.format("%.1f", gameTime)+ " seconds with "+this.numEnemies+" enemies!",
this.canvasWidth/4, this.canvasHeight/2 - 50);
return;
}
public void updateCanvas() {
long start = System.nanoTime();
this.goal.performAction();
// If the player is alive, this should move the player in the direction of the
// key that has been pressed
// Note: See keyPressed and keyReleased methods in the GameManager class.
this.player.performAction();
// If the enemy is alive, the enemy must move towards the Player. The Player object
// is obtained via the GameManager object that is given at the time of creating an Enemy
// object.
// Note: The amount that the enemy moves by must be much smaller than that of
// the player above or else the game becomes too hard to play.
for (int i = 0; i < this.numEnemies; i++) {
this.enemies[i].performAction();
}
if ((Math.abs(this.goal.getX() - this.player.getX()) < (this.goal.getCurrentImage().getWidth() / 2))
&& (Math.abs(this.goal.getY() - this.player.getY()) < (this.goal.getCurrentImage().getWidth() / 2))) {
for (int i = 0; i < this.numEnemies; i++) {
// Sets the image of the enemy to the "dead" image and sets its status to
// indicate dead
this.enemies[i].die();
}
// Sets the background of the stage to the finished game background.
this.stage.setGameOverBackground();
this.continueGame = false;
}
// If an enemy is close to the player or the goal, the player and goal die
int j = 0;
while (j < this.numEnemies) {
if ((Math.abs(this.player.getX() - this.enemies[j].getX()) < (this.player.getCurrentImage().getWidth() / 2))
&& (Math.abs(this.player.getY() - this.enemies[j].getY()) < (this.player.getCurrentImage().getWidth()
/ 2))) {
this.player.die();
this.goal.die();
this.stage.setGameOverBackground();
j = this.numEnemies;
this.continueGame = false;
}
else if ((Math.abs(this.goal.getX() - this.enemies[j].getX()) < (this.goal.getCurrentImage().getWidth() / 2))
&& (Math.abs(this.goal.getY() - this.enemies[j].getY()) < (this.goal.getCurrentImage().getWidth()
/ 2))) {
this.player.die();
this.goal.die();
this.stage.setGameOverBackground();
j = this.numEnemies;
this.continueGame = false;
}
j++;
}
try {
// Draw stage
this.canvasGraphics.drawImage(stage.getCurrentImage(), 0, 0, null);
// Draw goal
this.canvasGraphics.drawImage(this.goal.getCurrentImage(),
this.goal.getX() - (this.goal.getCurrentImage().getWidth() / 2),
this.goal.getY() - (this.goal.getCurrentImage().getHeight() / 2), null);
// Draw player
this.canvasGraphics.drawImage(player.getCurrentImage(),
this.player.getX() - (this.player.getCurrentImage().getWidth() / 2),
this.player.getY() - (this.player.getCurrentImage().getHeight() / 2), null);
// Draw enemies
for (int i = 0; i < this.numEnemies; i++) {
this.canvasGraphics.drawImage(this.enemies[i].getCurrentImage(),
this.enemies[i].getX() - (this.enemies[i].getCurrentImage().getWidth() / 2),
this.enemies[i].getY() - (this.enemies[i].getCurrentImage().getHeight() / 2), null);
}
} catch (Exception e) {
System.err.println(e.getMessage());
}
// Draw everything.
this.gameGraphics.drawImage(this.canvas, this.borderLeft, this.borderTop, this);
long end = System.nanoTime();
this.gameGraphics.setFont(new Font(this.gameGraphics.getFont().getFontName(), Font.PLAIN, 15));
this.gameGraphics.drawString("FPS: " + String.format("%2d", (int) (1000000000.0 / (end - start))),
this.borderLeft + 50, this.borderTop + 75);
return;
}
public Player getPlayer() {
return this.player;
}
public void keyPressed(KeyEvent ke) {
// Below, the setKey method is used to tell the Player object which key is
// currently pressed.
// The Player object must keep track of the pressed key and use it for
// determining the direction
// to move.
// Important: The setKey method in Player must not move the Player.
if (ke.getKeyCode() == KeyEvent.VK_LEFT)
this.player.setKey('L', true);
if (ke.getKeyCode() == KeyEvent.VK_RIGHT)
this.player.setKey('R', true);
if (ke.getKeyCode() == KeyEvent.VK_UP)
this.player.setKey('U', true);
if (ke.getKeyCode() == KeyEvent.VK_DOWN)
this.player.setKey('D', true);
if (ke.getKeyCode() == KeyEvent.VK_ESCAPE)
this.continueGame = false;
return;
}
#Override
public void keyReleased(KeyEvent ke) {
// Below, the setKey method is used to tell the Player object which key is
// currently released.
// The Player object must keep track of the pressed key and use it for
// determining the direction
// to move.
// Important: The setKey method in Player must not move the Player.
if (ke.getKeyCode() == KeyEvent.VK_LEFT)
this.player.setKey('L', false);
if (ke.getKeyCode() == KeyEvent.VK_RIGHT)
this.player.setKey('R', false);
if (ke.getKeyCode() == KeyEvent.VK_UP)
this.player.setKey('U', false);
if (ke.getKeyCode() == KeyEvent.VK_DOWN)
this.player.setKey('D', false);
return;
}
#Override
public void keyTyped(KeyEvent ke) {
return;
}
}
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import java.util.*;
public class Goal {
private int x;
private int y;
private BufferedImage imageCurrent;
private BufferedImage imageRunning;
private BufferedImage imageOver;
private int stepSize;
private Random rng; // Tip: Code that students write must not use randomness
public Goal(int x, int y) {
try {
this.imageRunning = ImageIO.read(new File("goal-alive.png"));
this.imageOver = ImageIO.read(new File("goal-dead.png"));
} catch (IOException e) {
e.printStackTrace();
}
this.x = x;
this.y = y;
this.stepSize = 10;
this.rng = new Random(x + y); // Tip: Code that students write (elsewhere) must not use any randomness.
this.imageCurrent = this.imageRunning;
return;
}
public void performAction() {
// The code below shows how the Goal can be moved by manipulating its x and y
// coordinates.
// Tip: Code that students write (elsewhere) must not use any randomness.
this.x += this.rng.nextInt() % stepSize;
this.y += this.rng.nextInt() % stepSize;
return;
}
public int getY() {
return this.y;
}
public int getX() {
return this.x;
}
public BufferedImage getCurrentImage() {
return this.imageCurrent;
}
public void die() {
this.imageCurrent = this.imageOver;
return;
}
}
import java.awt.Image;
public class Enemy {
private Image CurrentImage;
private int x;
private int y;
public Enemy(GameManager gameManager, int x, int y) {
}
public void performAction() {
}
public void die() {
}
public int getX() {
return this.x;
}
public int getY() {
return this.y;
}
public Image getCurrentImage() {
return CurrentImage;
}
}
import java.awt.Dimension;
public class Player {
private Dimension CurrentImage;
private int x;
private int y;
public Player(int x1, int y1) {
}
public void performAction() {
}
public int getX() {
return this.x;
}
public int getY() {
return this.y;
}
public Dimension getCurrentImage() {
return CurrentImage;
}
public void die() {
}
public void setKey(char c, boolean b) {
}
}
import java.awt.Image;
public class Stage {
public void setGameOverBackground() {
}
public Image getCurrentImage() {
return null;
}
}
Player.getCurrentImage() returns a Dimension, not an Image.
To be frank i have not the slightest clue how to fix this whats so ever. It works until you get to the part that only 1 brick shows and its kinda frustrating... If anyone could help me i would appreciate it. I did look up how to fix this but i didn't even find anyone that had this problem. Google searching isn't really that good. Oh and i used Eclipse for this program.
Board Class
package Final;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JPanel;
public class Board extends JPanel implements Commons {
private Timer timer;
private String message = "Your Fired";
private Ball ball;
private Paddle paddle;
private Brick bricks[];
private boolean ingame = true;
public Board() {
initBoard();
}
private void initBoard() {
addKeyListener(new TAdapter());
setFocusable(true);
bricks = new Brick[N_OF_BRICKS];
setDoubleBuffered(true);
timer = new Timer();
timer.scheduleAtFixedRate(new ScheduleTask(), DELAY, PERIOD);
}
#Override
public void addNotify() {
super.addNotify();
gameInit();
}
private void gameInit() {
ball = new Ball();
paddle = new Paddle();
int k = 0;
for (int i = 0; i < 5; i++) {
for (int j = 0; j < 6; j++) {
bricks[k] = new Brick(j * 40 + 30, i * 10 + 50);
k++;
}
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
if (ingame) {
drawObjects(g2d);
} else {
gameFinished(g2d);
}
Toolkit.getDefaultToolkit().sync();
}
private void drawObjects(Graphics2D g2d) {
g2d.drawImage(ball.getImage(), ball.getX(), ball.getY(),
ball.getWidth(), ball.getHeight(), this);
g2d.drawImage(paddle.getImage(), paddle.getX(), paddle.getY(),
paddle.getWidth(), paddle.getHeight(), this);
for (int i = 0; i < N_OF_BRICKS; i++) {
if (!bricks[i].isDestroyed()) {
g2d.drawImage(bricks[i].getImage(), bricks[i].getX(),
bricks[i].getY(), bricks[i].getWidth(),
bricks[i].getHeight(), this);
}
}
}
private void gameFinished(Graphics2D g2d) {
Font font = new Font("Verdana", Font.BOLD, 18);
FontMetrics metr = this.getFontMetrics(font);
g2d.setColor(Color.BLACK);
g2d.setFont(font);
g2d.drawString(message,
(Commons.WIDTH - metr.stringWidth(message)) / 2,
Commons.WIDTH / 2);
}
private class TAdapter extends KeyAdapter {
#Override
public void keyReleased(KeyEvent e) {
paddle.keyReleased(e);
}
#Override
public void keyPressed(KeyEvent e) {
paddle.keyPressed(e);
}
}
private class ScheduleTask extends TimerTask {
#Override
public void run() {
ball.move();
paddle.move();
checkCollision();
repaint();
}
}
private void stopGame() {
ingame = false;
timer.cancel();
}
private void checkCollision() {
if (ball.getRect().getMaxY() > Commons.BOTTOM_EDGE) {
stopGame();
}
for (int i = 0, j = 0; i < N_OF_BRICKS; i++) {
if (bricks[i].isDestroyed()) {
j++;
}
if (j == N_OF_BRICKS) {
message = "Pay Day";
stopGame();
}
}
if ((ball.getRect()).intersects(paddle.getRect())) {
int paddleLPos = (int) paddle.getRect().getMinX();
int ballLPos = (int) ball.getRect().getMinX();
int first = paddleLPos + 8;
int second = paddleLPos + 16;
int third = paddleLPos + 24;
int fourth = paddleLPos + 32;
if (ballLPos < first) {
ball.setXDir(-1);
ball.setYDir(-1);
}
if (ballLPos >= first && ballLPos < second) {
ball.setXDir(-1);
ball.setYDir(-1 * ball.getYDir());
}
if (ballLPos >= second && ballLPos < third) {
ball.setXDir(0);
ball.setYDir(-1);
}
if (ballLPos >= third && ballLPos < fourth) {
ball.setXDir(1);
ball.setYDir(-1 * ball.getYDir());
}
if (ballLPos > fourth) {
ball.setXDir(1);
ball.setYDir(-1);
}
}
for (int i = 0; i < N_OF_BRICKS; i++) {
if ((ball.getRect()).intersects(bricks[i].getRect())) {
int ballLeft = (int) ball.getRect().getMinX();
int ballHeight = (int) ball.getRect().getHeight();
int ballWidth = (int) ball.getRect().getWidth();
int ballTop = (int) ball.getRect().getMinY();
Point pointRight = new Point(ballLeft + ballWidth + 1, ballTop);
Point pointLeft = new Point(ballLeft - 1, ballTop);
Point pointTop = new Point(ballLeft, ballTop - 1);
Point pointBottom = new Point(ballLeft, ballTop + ballHeight + 1);
if (!bricks[i].isDestroyed()) {
if (bricks[i].getRect().contains(pointRight)) {
ball.setXDir(-1);
} else if (bricks[i].getRect().contains(pointLeft)) {
ball.setXDir(1);
}
if (bricks[i].getRect().contains(pointTop)) {
ball.setYDir(1);
} else if (bricks[i].getRect().contains(pointBottom)) {
ball.setYDir(-1);
}
bricks[i].setDestroyed(true);
}
}
}
}
}
Brick Class
package Final;
import javax.swing.ImageIcon;
public class Brick extends Sprite {
private boolean destroyed;
public Brick(int x, int y) {
ImageIcon ii = new ImageIcon("images/bricks.png");
image = ii.getImage();
i_width = image.getWidth(null);
i_heigth = image.getHeight(null);
destroyed = false;
}
public boolean isDestroyed() {
return destroyed;
}
public void setDestroyed(boolean val) {
destroyed = val;
}
}
Commons Class
package Final;
public interface Commons {
public static final int WIDTH = 300;
public static final int HEIGTH = 400;
public static final int BOTTOM_EDGE = 390;
public static final int N_OF_BRICKS = 30;
public static final int INIT_PADDLE_X = 200;
public static final int INIT_PADDLE_Y = 360;
public static final int INIT_BALL_X = 230;
public static final int INIT_BALL_Y = 355;
public static final int DELAY = 1000;
public static final int PERIOD = 10;
}
Sprite Class
package Final;
import java.awt.Image;
import java.awt.Rectangle;
public class Sprite {
protected int x;
protected int y;
protected int i_width;
protected int i_heigth;
protected Image image;
public void setX(int x) {
this.x = x;
}
public int getX() {
return x;
}
public void setY(int y) {
this.y = y;
}
public int getY() {
return y;
}
public int getWidth() {
return i_width;
}
public int getHeight() {
return i_heigth;
}
Image getImage() {
return image;
}
Rectangle getRect() {
return new Rectangle(x, y,
image.getWidth(null), image.getHeight(null));
}
}
Breakout Class
package Final;
import java.awt.EventQueue;
import javax.swing.JFrame;
public class Breakout extends JFrame {
public Breakout() {
initUI();
}
private void initUI() {
add(new Board());
setTitle("Lord Carl's Demolition Job");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(Commons.WIDTH, Commons.HEIGTH);
setLocationRelativeTo(null);
setResizable(false);
setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
Breakout game = new Breakout();
game.setVisible(true);
}
});
}
}
The problem is in checkCollision(). Inside the loop, j will never equal N_OF_BRICKS because of the loop condition. You could change to:
private void checkCollision() {
if (ball.getRect().getMaxY() > Commons.BOTTOM_EDGE) {
stopGame();
}
int j = 0;
for (int i = 0; i < N_OF_BRICKS; i++) {
if (bricks[i].isDestroyed()) {
j++;
}
}
if (j == N_OF_BRICKS) {
message = "Pay Day";
stopGame();
}
}
Also, in the Brick class you neglect to store the x,y coords:
public class Brick extends Sprite {
....
public Brick(int x, int y) {
ImageIcon ii = new ImageIcon("images/bricks.png");
image = ii.getImage();
i_width = image.getWidth(null);
i_heigth = image.getHeight(null);
destroyed = false;
// Save these
this.x = x;
this.y = y
}
....
}
Or, add a constructor to the Sprite class and call that from the Brick constructor:
public class Sprite {
....
public Sprite(int x, int y) {
this.x = x;
this.y = y;
}
....
}
public class Brick extends Sprite {
....
public Brick(int x, int y) {
// Call the sprite constructor
super(x, y);
ImageIcon ii = new ImageIcon("images/bricks.png");
image = ii.getImage();
i_width = image.getWidth(null);
i_heigth = image.getHeight(null);
destroyed = false;
}
....
}
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I'm a newbie in Java and just tried a tutorial of zetcode.com. He is explaining and showing in his Tutorial how to create a simple brickbreaker game, I read his tutorial and programmed the game as he did. At the end it wasnt working. the error is:
Exception in thread "main" java.lang.NullPointerException
at javax.swing.ImageIcon.(ImageIcon.java:205)
at breakout.Ball.(Ball.java:14)
at java.awt.Container.addNotify(Container.java:2769)
at javax.swing.JComponent.addNotify(JComponent.java:4741)
at java.awt.Container.addNotify(Container.java:2769)
at javax.swing.JComponent.addNotify(JComponent.java:4741)
at java.awt.Container.addNotify(Container.java:2769)
at javax.swing.JComponent.addNotify(JComponent.java:4741)
at javax.swing.JRootPane.addNotify(JRootPane.java:756)
at java.awt.Container.addNotify(Container.java:2769)
at java.awt.Window.addNotify(Window.java:770)
at java.awt.Frame.addNotify(Frame.java:487)
at java.awt.Window.show(Window.java:1031)
at java.awt.Component.show(Component.java:1651)
at java.awt.Component.setVisible(Component.java:1603)
at java.awt.Window.setVisible(Window.java:1014)
at breakout.Breakout.(Breakout.java:16)
at breakout.Breakout.main(Breakout.java:20)
Exception in thread "Timer-0" java.lang.NullPointerException
at breakout.Board$ScheduleTask.run(Board.java:95)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
Because im a Newbie I have no idea how to solve that problem. According to that problem I copy and pasted the code of the tutorial to exclude the possibility of mistakes in the code
here is the tutorial with the java code:
http://zetcode.com/tutorials/javagamestutorial/breakout/
I use Netbeans IDE 8.0
would be nice if someone could help me solving this problem :)
Edit:
as asked for ill paste all my code i have until now in here:
Commons.java
package breakout;
public interface Commons {
public static final int WIDTH = 300;
public static final int HEIGHT = 400;
public static final int BOTTOM = 390;
public static final int PADDLE_RIGHT = 250;
public static final int BALL_RIGHT = 280;
}
Sprite.java
package breakout;
import java.awt.Image;
import java.awt.Rectangle;
public class Sprite { //Basis Klasse für alle Objekte
protected int x;
protected int y;
protected int width;
protected int height;
protected Image image;
public void setX(int x){ //Jedes Objekt hat einen X-Wert
this.x = x;
}
public int getX(){
return x;
}
public void setY(int y){ //Jedes Objekt hat einen Y-Wert
this.y = y;
}
public int getY(){
return y;
}
public int getWidth(){ //Jedes Objekt hat eine Weite
return width;
}
public int getHeight(){ //Jedes Objekt hat eine Höhe
return height;
}
Image getImage(){ //Jedes Objekt hat ein Bild zur darstellung
return image;
}
Rectangle getRect(){ //Jedes Objekt wird mit einem Rectangle definiert
return new Rectangle(x,y,
image.getWidth(null), image.getHeight(null));
}
}
Brick.java
package breakout;
import javax.swing.ImageIcon;
public class Brick extends Sprite {
String brickie = "../../images/brickie.png";
boolean destroyed;
public Brick(int x, int y){
this.x = x;
this.y = y;
ImageIcon ii = new ImageIcon(this.getClass().getResource(brickie));
image = ii.getImage();
width = image.getWidth(null);
height = image.getHeight(null);
destroyed = false;
}
public boolean isDestroyed(){
return destroyed;
}
public void setDestroyed(boolean destroyed){
this.destroyed = destroyed;
}
}
Ball.java
package breakout;
import javax.swing.ImageIcon;
public class Ball extends Sprite implements Commons{
private int xdir;
private int ydir;
protected String ball = "../../images/ball.png";
public Ball(){
xdir = 1;
ydir = -1;
ImageIcon ii = new ImageIcon(this.getClass().getResource(ball));
image = ii.getImage();
width = image.getWidth(null);
height = image.getHeight(null);
resetState();
}
public void move(){
x += xdir;
y += ydir;
if(x == 0){
setXDir(1);
}
if(x == BALL_RIGHT){
setXDir(-1);
}
if(y == 0){
setYDir(1);
}
}
public void resetState()
{
x = 230;
y = 355;
}
public void setXDir(int x)
{
xdir = x;
}
public void setYDir(int y)
{
ydir = y;
}
public int getYDir()
{
return ydir;
}
}
Paddle.java
package breakout;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;
public class Paddle extends Sprite implements Commons{
String paddle = "../../images/paddle.png";
int dx;
public Paddle(){
ImageIcon ii= new ImageIcon(this.getClass().getResource(paddle));
image = ii.getImage();
width = image.getWidth(null);
height = image.getHeight(null);
resetState();
}
public void move(){
x += dx;
if(x <= 2)
x = 2;
if(x >= Commons.PADDLE_RIGHT)
x = Commons.PADDLE_RIGHT;
}
public void keypressed(KeyEvent e){
int key = e.getKeyCode();
if(key == KeyEvent.VK_LEFT){
dx = -2;
}
if(key == KeyEvent.VK_RIGHT){
dx = 2;
}
}
public void keyReleased(KeyEvent e){
int key = e.getKeyCode();
if(key == KeyEvent.VK_LEFT){
dx = 0;
}
if(key == KeyEvent.VK_RIGHT){
dx = 0;
}
}
public void resetState(){
x = 200;
y = 360;
}
}
Board.java
package breakout;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JPanel;
public class Board extends JPanel implements Commons{
Image ii;
Timer timer;
String message = "Game Over";
Ball ball;
Paddle paddle;
Brick bricks[];
boolean ingame = true;
int timerId;
public Board(){
addKeyListener(new TAdapter());
setFocusable(true);
bricks = new Brick[30];
setDoubleBuffered(true);
timer = new Timer();
timer.scheduleAtFixedRate(new ScheduleTask(), 1000, 10);
}
public void addNotify(){
super.addNotify();
gameInit();
}
public void gameInit(){
ball = new Ball();
paddle = new Paddle();
int k = 0;
for (int i = 0; i < 5; i++) {
for (int j = 0; j < 6; j++) {
bricks[k] = new Brick(j * 40 + 30, i * 10 + 50);
k++;
}
}
}
public void paint(Graphics g){
super.paint(g);
if(ingame) {
g.drawImage(ball.getImage(), ball.getX(), ball.getY(),
ball.getWidth(), ball.getHeight(), this);
g.drawImage(paddle.getImage(), paddle.getX(), paddle.getY(),
paddle.getWidth(), paddle.getHeight(), this);
for (int i = 0; i < 30; i++) {
if (!bricks[i].isDestroyed())
g.drawImage(bricks[i].getImage(), bricks[i].getX(),
bricks[i].getY(), bricks[i].getWidth(),
bricks[i].getHeight(), this);
}
}else{
Font font = new Font("Verdana",Font.BOLD, 18);
FontMetrics metr = this.getFontMetrics(font);
g.setColor(Color.BLACK);
g.setFont(font);
g.drawString(message,
(Commons.WIDTH - metr.stringWidth(message))
/2,Commons.WIDTH /2);
}
Toolkit.getDefaultToolkit().sync();
g.dispose();
}
private class TAdapter extends KeyAdapter{
public void keyReleased(KeyEvent e){
paddle.keyReleased(e);
}
public void keyPressed(KeyEvent e){
paddle.keypressed(e);
}
}
class ScheduleTask extends TimerTask{
public void run(){
ball.move();
paddle.move();
checkCollision();
repaint();
}
}
public void stopGame(){
ingame = false;
timer.cancel();
}
public void checkCollision(){
if (ball.getRect().getMaxY() > Commons.BOTTOM){
stopGame();
}
for(int i = 0, j = 0; i < 30; i++){
if(bricks[i].isDestroyed()){
j++;
}
if(j == 30){
message = "Victory";
stopGame();
}
}
if ((ball.getRect()).intersects(paddle.getRect())) {
int paddleLPos = (int)paddle.getRect().getMinX();
int ballLPos = (int)ball.getRect().getMinX();
int first = paddleLPos + 8;
int second = paddleLPos + 16;
int third = paddleLPos + 24;
int fourth = paddleLPos + 32;
if (ballLPos < first) {
ball.setXDir(-1);
ball.setYDir(-1);
}
if (ballLPos >= first && ballLPos < second) {
ball.setXDir(-1);
ball.setYDir(-1 * ball.getYDir());
}
if (ballLPos >= second && ballLPos < third) {
ball.setXDir(0);
ball.setYDir(-1);
}
if (ballLPos >= third && ballLPos < fourth) {
ball.setXDir(1);
ball.setYDir(-1 * ball.getYDir());
}
if (ballLPos > fourth) {
ball.setXDir(1);
ball.setYDir(-1);
}
}
for (int i = 0; i < 30; i++) {
if ((ball.getRect()).intersects(bricks[i].getRect())) {
int ballLeft = (int)ball.getRect().getMinX();
int ballHeight = (int)ball.getRect().getHeight();
int ballWidth = (int)ball.getRect().getWidth();
int ballTop = (int)ball.getRect().getMinY();
Point pointRight =
new Point(ballLeft + ballWidth + 1, ballTop);
Point pointLeft = new Point(ballLeft - 1, ballTop);
Point pointTop = new Point(ballLeft, ballTop - 1);
Point pointBottom =
new Point(ballLeft, ballTop + ballHeight + 1);
if (!bricks[i].isDestroyed()) {
if (bricks[i].getRect().contains(pointRight)) {
ball.setXDir(-1);
}
else if (bricks[i].getRect().contains(pointLeft)) {
ball.setXDir(1);
}
if (bricks[i].getRect().contains(pointTop)) {
ball.setYDir(1);
}
else if (bricks[i].getRect().contains(pointBottom)) {
ball.setYDir(-1);
}
bricks[i].setDestroyed(true);
}
}
}
}
}
Breakout.java
package breakout;
import javax.swing.JFrame;
public class Breakout extends JFrame {
public Breakout()
{
add(new Board());
setTitle("Breakout");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(Commons.WIDTH, Commons.HEIGHT);
setLocationRelativeTo(null);
setIgnoreRepaint(true);
setResizable(false);
setVisible(true);
}
public static void main(String[] args) {
new Breakout();
}
}
All code should be like in the Tutorial except the paths to the images, i edited on my own
It just that compiler is not able to find ImageIcon source that u have provide for setting image.
Do one thing for checking this stuff. have other Image URL and set it to that position. and Run it again.
I assume that you don't have brickie resource.
Simply you have to have image on that path in resources "../images/brickie.png"
The exception you're getting is telling you that line 205 of ImageIcon.java, an internal Java class, is referencing a null object. Reading on the error, the next reference is in your code, Ball.java on line 14.
This is the line:
ImageIcon ii = new ImageIcon(this.getClass().getResource(ball));
what's happening here is that the call to this.getClass().getResource(ball) is returning null and it's crashing the program. This is probably because the relative path that you've set to "../images/brickie.png" is not actually correct.
I'd suggest trying an absolute path to the file to get this working for now.
I have never tried to implement shooting in any kind of game before and when I try to remove and element of the ArrayList I'm using it throws and index out of bounds exception. I want to be able to press the enter key, store the current direction that the player is facing and then shoot a projectile in that current direction. Then, once a projectile has reached its destination to remove itself from the ArrayList and not be rendered anymore. However, when it reaches the end of the map (x == Map.mapSizeX), the bullet freezes and that's when the exception is thrown. (Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 1, Size: 1).
Code for the shooting class (Projectile.java)
package Engine;
import java.awt.Color;
import java.awt.Graphics2D;
import java.util.ArrayList;
import java.util.Random;
public class Projectile {
public static ArrayList<Integer> bullets = new ArrayList<Integer>(3);
private static DirectionalVector dir = new DirectionalVector();
private static int index = 0;
private static int x,y;
public Projectile(int direction, int x, int y){
dir.applyDirection(direction);
bullets.add(index);
index += 1;
this.x = x;
this.y = y;
}
public void updatePos(){
if (dir.right){
x += 1;
dir.left = false;
dir.down = false;
}
if (dir.left){
x -= 1;
dir.right = false;
dir.down = false;
}
if (dir.down){
y += 1;
dir.left = false;
dir.right = false;
}
if (dir.down){
System.out.println("DOWN");
}
if (dir.right){
System.out.println("RIGHT");
}
if (dir.left){
System.out.println("LEFT");
}
if (x > Map.mapSizeX){
bullets.remove(index);
}
if (x < 0){
bullets.remove(index);
}
if (y > Map.mapSizeY){
bullets.remove(index);
}
if (y < 0){
bullets.remove(index);
}
}
public static void render(Graphics2D g2){
int r = new Random().nextInt(256);
int g = new Random().nextInt(256);
int b = new Random().nextInt(256);
if (r < 50){
r = new Random().nextInt(256);
}
if (g < 50){
g = new Random().nextInt(256);
}
if (b < 50){
b = new Random().nextInt(256);
}
g2.setColor(new Color(r,g,b));
g2.fillRect(x * Map.tileSize, y * Map.tileSize, Map.tileSize, Map.tileSize);
}
Code for the DirectionalVector class
package Engine;
public class DirectionalVector {
public boolean left = false, right = true, down = false;
public DirectionalVector(){
}
public void applyDirection(int id){
if (id == 0){
right = true;
}
if (id == 1){
left = true;
}
if (id == 2){
down = true;
}
}
}
Code for the Player class
package Engine;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class Player implements KeyListener, Runnable{
public static int x = 0,y = 0;
private static boolean right = false, left = false, falling = false, jumping = false;
private Thread thread = new Thread(this, "GAME LOOP");
private static int lastDirectionPressed = 0;
public static Projectile bullet;
public Player(){
thread.start();
}
public void renderPlayer(boolean value, Graphics2D g2){
if (value){
g2.setColor(Color.blue);
g2.fillRect(x * Map.tileSize, y * Map.tileSize, Map.tileSize, Map.tileSize);
}
}
#Override
public void keyPressed(KeyEvent e) {
int c = e.getKeyCode();
if (c == KeyEvent.VK_RIGHT && right){
x += 1;
lastDirectionPressed = 0;
}
if (c == KeyEvent.VK_LEFT && left){
x -= 1;
lastDirectionPressed = 1;
}
if (c == KeyEvent.VK_SPACE && jumping){
y -= 1;
}
if (c == KeyEvent.VK_ENTER){
bullet = new Projectile(lastDirectionPressed, x, y);
}
}
public void update(){
if (x != Map.mapSizeX){
right = Map.getTile(x + 1, y) == 0;
}
if (x > 0){
left = Map.getTile(x - 1, y) == 0;
}
if (x == 0){
left = false;
}
if (x == Map.mapSizeX){
right = false;
}
if (y != Map.mapSizeY){
falling = Map.getTile(x, y + 1) == 0;
}
if (y == Map.mapSizeY){
falling = false;
}
if (falling){
y += 1;
}
}
#Override
public void keyReleased(KeyEvent e) {
}
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void run(){
while (true){
try{
Thread.sleep(100);
update();
}catch (InterruptedException e){
e.printStackTrace();
}
}
}
}
Code for the ContentPane class (Where all the rendering occurs)
package Engine;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
#SuppressWarnings({"serial", "static-access"})
public class ContentPane extends JPanel{
private Map map = new Map();
public Player player = new Player();
public ContentPane(){
}
public void paintComponent(Graphics g){
Graphics2D g2 = (Graphics2D) g;
super.paintComponent(g2);
map.renderMap(true, g2);
player.renderPlayer(true, g2);
if (player.bullet.bullets.size() > 0){
player.bullet.updatePos();
}
for (int i = 0; i < player.bullet.bullets.size(); i++){
player.bullet.render(g2);
}
System.out.println(player.bullet.bullets.size());
repaint();
}
}
EDIT: This is an SSCCE to demonstrate my problem.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.awt.Graphics2D;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
public class Main {
public static BufferedImage map, tileSand, tileSea;
public static void main(String[] args) {
map = new BufferedImage(50, 50, BufferedImage.TYPE_INT_ARGB);
for(int x = 0; x < 50 ; x++){
for(int y = 0; y < 50 ; y++){
boolean colour = Math.random() < 0.5;
if (colour){
map.setRGB(x, y, -256);
} else {
map.setRGB(x, y, -16776961);
}
}
}
tileSand = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
Graphics g = tileSand.getGraphics();
g.setColor(Color.YELLOW);
g.fillRect(0, 0, 32, 32);
tileSea = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
g.setColor(Color.BLUE);
g = tileSea.getGraphics();
g.fillRect(0, 0, 32, 32);
Island test = new Main.Island();
test.start();
long start, sleep;
while(true) {
start = System.currentTimeMillis();
test.getCanvas().requestFocus();
test.getCanvas().repaint();
sleep = 15-(System.currentTimeMillis()-start);
try {
Thread.sleep(sleep > 0 ? sleep : 0);
} catch (InterruptedException e) {
}
}
}
static class Island implements Runnable {
private Tile[][] tiles;
private JFrame frame;
private JPanel panel;
private Thread logicThread;
private boolean running = false;
private boolean paused = false;
private Image image;
private Player player;
public Island() {
image = new BufferedImage(1027, 768, BufferedImage.TYPE_INT_ARGB);
player = new Player();
tiles = new Tile[map.getWidth()][map.getHeight()];
int rgb;
for(int x = 0; x < map.getWidth(); x++) {
for(int y = 0; y < map.getHeight(); y++) {
rgb = map.getRGB(x, y);
switch (rgb) {
case -16776961: tiles[x][y] = new Tile("sea");
break;
case -256: tiles[x][y] = new Tile("sand");
break;
}
}
}
makeMap();
makeFrame();
addBindings();
logicThread = new Thread(this);
}
public JPanel getCanvas() {
return panel;
}
public void start() {
running = true;
paused = false;
logicThread.start();
}
public void run() {
long sleep, before;
while(running){
before = System.currentTimeMillis();
player.move();
try {
sleep = 15-(System.currentTimeMillis()-before);
Thread.sleep(sleep > 0 ? sleep : 0);
} catch (InterruptedException ex) {
}
while(running && paused);
}
paused = false;
}
private void makeFrame() {
frame = new JFrame("Island");
panel = new JPanel(){
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) image.getGraphics();
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, 1024, 768);
long xl, yl;
xl = player.getLocation().x-512;
yl = player.getLocation().y-384;
int x2, y2;
x2 = (int) Math.floor(xl / 32);
y2 = (int) Math.floor(yl / 32);
int xoffset, yoffset;
xoffset = (int) (xl % 32);
yoffset = (int) (yl % 32);
for(int x = x2; x < x2+40; x++) {
for(int y = y2; y < y2+40; y++) {
if (x < tiles.length && x > 0 && y < tiles[0].length && y > 0) {
g2d.drawImage(tiles[x][y].getContent(), (x-x2)*32 - xoffset, (y-y2)*32 - yoffset, null);
}
}
}
g.drawImage(image, 0, 0, null);
}
};
panel.setPreferredSize(new Dimension(1024, 768));
panel.setIgnoreRepaint(true);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
private void addBindings() {
InputMap inputMap = panel.getInputMap();
ActionMap actionMap = panel.getActionMap();
inputMap.put(KeyStroke.getKeyStroke("Q"),"hold-sprint");
actionMap.put("hold-sprint", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.sprint(true);
}
});
inputMap.put(KeyStroke.getKeyStroke("released Q"),"release-sprint");
actionMap.put("release-sprint", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.sprint(false);
}
});
inputMap.put(KeyStroke.getKeyStroke("RIGHT"),"hold-right");
actionMap.put("hold-right", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.right(true);
}
});
inputMap.put(KeyStroke.getKeyStroke("released RIGHT"),"release-right");
actionMap.put("release-right", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.right(false);
}
});
inputMap.put(KeyStroke.getKeyStroke("DOWN"),"hold-down");
actionMap.put("hold-down", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.down(true);
}
});
inputMap.put(KeyStroke.getKeyStroke("released DOWN"),"release-down");
actionMap.put("release-down", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.down(false);
}
});
inputMap.put(KeyStroke.getKeyStroke("LEFT"),"hold-left");
actionMap.put("hold-left", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.left(true);
}
});
inputMap.put(KeyStroke.getKeyStroke("released LEFT"),"release-left");
actionMap.put("release-left", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.left(false);
}
});
inputMap.put(KeyStroke.getKeyStroke("UP"),"hold-up");
actionMap.put("hold-up", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.up(true);
}
});
inputMap.put(KeyStroke.getKeyStroke("released UP"),"release-up");
actionMap.put("release-up", new AbstractAction() {
public void actionPerformed(ActionEvent e) {
player.up(false);
}
});
}
private void makeMap() {
for(int x = 0; x < tiles.length; x++) {
for(int y = 0; y < tiles[0].length; y++) {
switch (tiles[x][y].getType()) {
case "sea": tiles[x][y].setContent(tileSea);
break;
case "sand": tiles[x][y].setContent(tileSand);
break;
}
}
}
}
}
static class Player{
private Point location;
private int xspeed, yspeed;
private boolean left, up, right, down, sprint;
public Player() {
location = new Point(0, 0);
left = false;
up = false;
right = false;
down = false;
sprint = false;
xspeed = yspeed = 0;
}
public void left(boolean state){
left = state;
}
public void up(boolean state){
up = state;
}
public void right(boolean state){
right = state;
}
public void down(boolean state){
down = state;
}
public void sprint(boolean state) {
sprint = state;
}
public void move() {
if (sprint) {
if (left) {
if(xspeed>-10)
xspeed--;
} if (right) {
if(xspeed<10)
xspeed++;
} if (up) {
if(yspeed>-10)
yspeed--;
} if (down) {
if(yspeed<10)
yspeed++;
}
} else {
if (left) {
if(xspeed>-5)
xspeed--;
} if (right) {
if(xspeed<5)
xspeed++;
} if (up) {
if(yspeed>-5)
yspeed--;
} if (down) {
if(yspeed<5)
yspeed++;
}
}
if (!sprint) {
if (xspeed > 5) {
xspeed--;
} if (xspeed < -5) {
xspeed++;
} if (yspeed > 5) {
yspeed--;
} if (yspeed < -5) {
yspeed++;
}
}
if (!left && !right) {
if (xspeed > 0) {
xspeed--;
} if (xspeed < 0) {
xspeed++;
}
} if (!up && !down) {
if (yspeed > 0) {
yspeed--;
} if (yspeed < 0) {
yspeed++;
}
}
location.x = location.x + xspeed;
location.y = location.y + yspeed;
}
public Point getLocation() {
return location;
}
}
static class Tile {
private String type;
private BufferedImage tile;
public Tile(String type) {
this.type = type;
}
public String getType() {
return type;
}
public void setContent(BufferedImage newTile) {
tile = newTile;
}
public BufferedImage getContent() {
return tile;
}
}
}
I have a JPanel with a modified paintComponent method. In this method I draw the relevant tiles from a 2d array to the screen based on the player location. I draw all my tiles to a BufferedImage and then I apply it to the screen at the end of the paint method. In theory this should not create tearing as I am double buffering? Here is the appropriate code, image is just a BufferedImage with the dimensions of the screen:
public void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) image.getGraphics();
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, 1024, 768);
long xl, yl;
xl = player.getLocation().x-512;
yl = player.getLocation().y-384;
int x2, y2;
x2 = (int) Math.floor(xl / 32);
y2 = (int) Math.floor(yl / 32);
int xoffset, yoffset;
xoffset = (int) (xl % 32);
yoffset = (int) (yl % 32);
for(int x = x2; x < x2+40; x++) {
for(int y = y2; y < y2+40; y++) {
if (x < tiles.length && x > 0 && y < tiles[0].length && y > 0) {
g2d.drawImage(tiles[x][y].getContent(), (x-x2)*32 - xoffset, (y-y2)*32 - yoffset, null);
}
}
}
g.drawImage(image, 0, 0, null);
}
I think the tearing could possibly be caused by the player's location changing over the duration of the paint method causing the tiles not to match up, the faster the player goes the more obvious the effect is. However I get the players location at the start and store it in two longs, I was under the impression that longs are passed by value not reference so the player location should be constant whilst the method runs.
I am happy to provide more code :), and thanks in advance.
Just so if people find my question and wonder what I ended up doing to "fix" it, switch over to c++ and SDL or some other image library before you are to far into your project, it's simply better for this kind of thing.