Develop Reference

Breakout brick collision in java

I have been working on a Breakout game and have just about everything done except for the brick collision. The ball bounces of the wall, paddle and the brick. However when the ball bounces of the brick, the brick does not disappear. I am really stuck on this. Any ideas are greatly appreciated.
What I have for brick, ball and main class:
Brick Class:
import java.awt.*;
import java.applet.*;
public class Brick2{
private int x;
private int y;
public Brick2(int X, int Y){
x =X;
y=Y;
}
public void update(Ball ba){
collision(ba);
}
public void collision(Ball ba){
int bX = ba.getX();
int bY = ba.getY();
int bHeight = ba.getImageHeight();
int bWidth = ba.getImageWidth();
for(int x=0; x <= 600; x+=55){
for (int y=0; y<= 100; y+=25){
if (bX-bWidth<=x && bX+bWidth>=x && bY-bHeight<=y && bY+bHeight>=y){
ba.setXVel(6);
}
}
}
}
public int getX(){
return x;
}
public int getY(){
return y;
}
public void paint(Graphics g){
for(int x=0; x <= 800; x+=55){
for (int y=0; y<= 100; y+=25){
g.setColor(Color.RED);
g.fillRect(x,y,50,20);
}
}
}
}
Ball Class:
import java.awt.*;
import java.applet.*;
public class Ball {
private int x=355 ;
private int y=200;
private int speed = 6;
private int xVel = -speed;
private int yVel = speed;
private boolean gameOver = false;
private Image ball;
public Ball (Breakout bR){
ball = bR.getImage(bR.getDocumentBase(),"ball.png");
}
public void update(Breakout bR, Paddle p){
x += xVel;
y += yVel;
if (x < 0){
xVel = speed;
}
else if (x > bR.getWidth()){
xVel = -speed;
}
if(y > bR.getHeight()){
gameOver = true;
}
else if (y < 0){
yVel = speed;
}
collision(p);
}
public void collision(Paddle p){
int pX = p.getX();
int pY = p.getY();
int pHeight = p.getImageHeight();
int pWidth = p.getImageWidth();
if (pX<=x && pX+pWidth>=x && pY-pHeight<=y && pY+pHeight>=y){
yVel = -speed;
}
}
public int getX(){
return x;
}
public int getY(){
return y;
}
public int getImageWidth(){
return ball.getWidth(null);
}
public int getImageHeight(){
return ball.getHeight(null);
}
public void setXVel(int xv){
yVel = xv;
}
public void paint (Graphics g, Breakout bR){
g.drawImage(ball,x,y,bR);
if (gameOver){
g.setColor(Color.WHITE);
g.drawString("Game Over", 100,300);
}
}
}
Main Class:
import java.applet.*;
import java.awt.*;
public class Breakout extends Applet implements Runnable{
Thread thread = new Thread(this);
boolean running = true;
//Brick b;
Brick2 b2;
Paddle p;
Ball ba;
Image dbImage;
Graphics dbg;
public void init(){
setSize(800,600);
//b = new Brick(this);
b2 = new Brick2(0,0);
p = new Paddle(this);
ba = new Ball(this);
}
public void start(){
thread.start();
}
public void destroy(){
running = false;
}
public void stop(){
running = false;
}
public void run(){
while(running){
//b.update(this,ba);
b2.update(ba);
p.update(this);
ba.update(this,p);
repaint();
try{
thread.sleep(20);
}
catch (InterruptedException e){
System.out.println("AN ERROR HAS OCCURED");
}
}
}
public void update(Graphics g, Brick2 b){
dbImage = createImage(getWidth(),getHeight());
dbg = dbImage.getGraphics();
paint(dbg);
g.drawImage(dbImage,0,0,this);
}
public void paint(Graphics g){
g.fillRect(0,0,800,600);
//b.paint(g,this);
b2.paint(g);
p.paint(g,this);
ba.paint(g,this);
}
}
Thanks for your help.

You could add a boolean isDestroyed = false in your Brick Class. Once the Ball touches the Brick (in your collision() method), set isDestroyed = true and stop drawing/interacting with that Brick :) Don't forget to make that brick = null so it frees up memory later :)
The best way to do this would be to create the boolean isDestroyed as a private variable and get its' value with a isDestroyed method:
public class Brick2 {
private boolean isDestroyed = false;
public boolean isDestroyed() {
return isDestroyed;
}
public void setIsDestroyed(boolean newValue) {
isDestroyed = newValue;
}
}
Then, in your Main class, before calling b2.paint(), check if b2.isDestroyed returns true:
public class Breakout...{
public void paint(...) {
if(b2 != null && !b2.isDestroyed())
b2.paint(g);
else
b2 = null;
}
BUT, if I were you, I would create an ArrayList of Bricks and add/remove them through the ArrayList. They will be easier to manage that way :) Hola if you need anything else.

Treat an array of bricks the same way you would treat any other collection of objects. You can use List<brick> = new ArrayList<brick>();
Brick should have four coordinates and shape would fit well for this purpose, int brickLife = 1 that changes to zero once the ball breaks it. You might want to increase the value to add sturdy bricks.

Java Applet Timer and Jumping

Okay, I kind of need lots of help, so whatever advice anyone has would be much appreciated! I am trying to write a running/jumping game where the player/ball must avoid the blocks to reach the finish line as quickly as possible. Right now, my two main issues are the jumping action and creating a timer. When my player jumps, it goes up, and then down.
I have included the following code in my Circle class:
public void horiz(int val){
for(int c = 0; c<val+1; c++){
x++;
repaint();}
}
public void vert(int val){
y += val;
}
public void down(int val){
y += val;
}
And then It is executed through buttons:
public void actionPerformed(ActionEvent e){
if(e.getSource() instanceof Button){
if(e.getSource() == run)
player.horiz(10);
else if (e.getSource()== jump){
player.vert(-10);
}
repaint();
collision();
}
In order to get the player to go up, and then back down, I had tried this...
public void actionPerformed(ActionEvent e){
if(e.getSource() instanceof Button){
if(e.getSource() == run)
player.horiz(10);
else if (e.getSource()== jump){
player.vert(-10);
repaint();
player.down(10);
}
repaint();
collision();
}
But I think I need to have it wait a few seconds before coming back down. I have read a bunch about swing, util, and robot timers, but I do not know which/how to implement them here.
My other problem is creating a timer that displays the time elapsed since the game has started. I thing This could be execute similarly to the jumping timer, but, again, I am unsure which type of timer I should be using.
If I am right, I cannot use swing because my program is written in AWT? Please excuse the awful colors, I am still figuring out the basics. Thanks so much for any advice of help you can give me! :)
Here is the full code:
import java.awt.*;
import java.awt.Rectangle;
import java.awt.Shape;
import javafx.scene.shape.*;
import java.awt.event.*;
import java.util.Random;
import java.util.Timer;
import javax.swing.JOptionPane;
import java.awt.Toolkit;
import java.util.Timer;
import java.util.TimerTask;
import java.applet.Applet;
public class TryingAgain extends Applet
implements ActionListener{
//creates arrays of rect values
int[]xA = new int[10];
int[]yA = new int[10];
int[]widthA = new int[10];
int[]heightA = new int[10];
private Rectangle rectangle;
//creates buttons to move player
private Button run = new Button("Run");
private Button jump = new Button("Jump");
//creates player and obstacles
private Circle player = new Circle(110,110,20);
private makeRect block = new makeRect();
private finishLine line = new finishLine();
//initiates the buttons with actionListener
public void init(){
this.setSize(new Dimension(1300,500));
setBackground(Color.GREEN);
add(run);
add(jump);
run.addActionListener(this);
jump.addActionListener(this);
}
//draws the player and blocks on the screen
public void paint(Graphics g){
player.draw(g);
block.draw(g);
line.draw(g);
}
//if methods to be control movement
public void actionPerformed(ActionEvent e){
if(e.getSource() instanceof Button){
if(e.getSource() == run)
player.horiz(10);
else if (e.getSource()== jump){
player.vert(-10);
}
repaint();
collision();
}
}
public void collision(){
if(crashTest() == true){
JOptionPane.showMessageDialog(this, "Game Over", "Game Over", JOptionPane.YES_NO_OPTION);
System.exit(ABORT);
}
if(winTest() == true){
JOptionPane.showMessageDialog(this, "You Finished!", "You Finished!", JOptionPane.PLAIN_MESSAGE);
}
}
class Circle{
private int radius;
private int x,y;
public Circle(){
x = 110; y = 110;
radius = 20;
}
public Circle(int x0, int y0, int rad){
x = x0; y = y0; radius = rad;
}
public void draw(Graphics g){
g.setColor(Color.CYAN);
g.fillOval(x - radius, y-radius, 2*radius, 2*radius);
}
public void horiz(int val){
for(int c = 0; c<val+1; c++){
x++;
repaint();}
}
public void vert(int val){
y += val;
}
public void down(int val){
y += val;
}
public Rectangle getBounds(){
return new Rectangle(x-radius, y-radius, 2*radius, 2*radius);
}
}
class makeRect{
private int Xmax = 150;
private int Xmin = 50;
private int Wmax = 50;
private int Hmax = 25;
private int Wmin = 10;
private int Hmin = 5;
Random rand = new Random();
int randx = rand.nextInt((Xmax-Xmin)+1)+Xmin;
int randh = rand.nextInt((Hmax-Hmin)+1)+Hmin;
int randw = rand.nextInt((Wmax-Wmin)+1)+Wmin;
//fills arrays
{for(int i = 0; i < 10; i++){
Random rand = new Random();
int randx = rand.nextInt((Xmax-Xmin)+1)+Xmin;
int randh = rand.nextInt((Hmax-Hmin)+1)+Hmin;
int randw = rand.nextInt((Wmax-Wmin)+1)+Wmin;
if(i>0)
xA[i] = (randx+xA[i-1]);
else
xA[i] = 160;
yA[i] = randh+110;
widthA[i] = randw;
heightA[i] = randh;
}
}
private int x, y, width, height;
public makeRect(){
x = 150; y = 120; width = 30; height = 10;
}
public void makeRect(int x0, int y0, int w0, int h0){
x = x0; y = y0; width = w0; height = h0;
}
public void draw(Graphics g) {
g.setColor(Color.ORANGE);
{for(int i = 0; i < 10; i++){
g.fillRect(xA[i], yA[i], heightA[i], widthA[i]);
}}
}
public Rectangle getBounds(){
return new Rectangle(randx, 110+randh, 30, 10);
}
}
class finishLine{
private int x, y, width, height;
public void finishLine(int x0, int y0, int w0, int h0){
x = x0; y = y0; width = w0; height = h0;
}
public void draw(Graphics g){
g.setColor(Color.MAGENTA);
g.fillRect(1200, 80, 30, 30);
}
}
public boolean crashTest(){
boolean end = false;
{for(int i = 0; i<10; i++){
if(player.getBounds().intersects(new Rectangle(xA[i], yA[i], heightA[i], widthA[i])))
end = true;
}
return end;
}
}
public boolean winTest(){
boolean win = false;
if(player.getBounds().intersects(new Rectangle(1200, 80, 30, 30)))
win = true;
return win;
}
}

Java-Pong AI not moving

I am making pong in java but the enemy AI is not moving. It should move to the direction the ball goes to. Please can someone help me?
Main class:
import javax.swing.*;
public class Main extends JFrame{
final static int WW = 800;
final static int WH = 600;
public Main(){
setSize(WW,WH);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setTitle("Pong");
add(new GamePanel());
setVisible(true);
}
public static void main(String[] args){
new Main();
}
}
GamePanel class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class GamePanel extends JPanel implements ActionListener,KeyListener{
Player player = new Player();
Computer computer = new Computer();
Ball ball = new Ball();
public GamePanel(){
Timer time = new Timer(20, this);
time.start();
this.addKeyListener(this);
this.setFocusable(true);
}
private void update(){
player.update();
ball.update();
ball.Collision(player);
computer.update();
ball.Collision(computer);
}
public void paintComponent(Graphics g){
g.setColor(Color.BLACK);
g.fillRect(0, 0, Main.WW, Main.WH);
player.paint(g);
ball.paint(g);
computer.paint(g);
}
public void actionPerformed(ActionEvent e){
update();
repaint();
}
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == KeyEvent.VK_UP){
player.setyv(-10);
}
else if(e.getKeyCode() == KeyEvent.VK_DOWN){
player.setyv(10);
}
}
public void keyReleased(KeyEvent e){
if(e.getKeyCode()==KeyEvent.VK_UP || e.getKeyCode()==KeyEvent.VK_DOWN)
player.setyv(0);
}
public void keyTyped(KeyEvent e){
}
}
Player class:
import java.awt.*;
public class Player {
private int y = 300;
private int w = 20;
private int h = 120;
private int yv = 0;
private int x = 700;
public Player(){
}
public void update(){
y = y + yv;
}
public void paint(Graphics g){
g.setColor(Color.WHITE);
g.fillRect(x,y,w,h);
}
public void setyv(int speed){
yv = speed;
}
public int getX(){
return this.x;
}
public int getY(){
return this.y;
}
public int getW(){
return this.w;
}
public int getH(){
return this.h;
}
}
Ball class:
import java.awt.*;
public class Ball {
private int x = 400;
private int y = 300;
private int xv = -10;
private int yv = 10;
public void update(){
x = x += xv;
y = y += yv;
if(x < 10){
xv = 10;
}
if(x > 770){
xv = -10;
}
if(y < 10){
yv = 5;
}
if(y > 550){
yv = -5;
}
}
public int getY(){
return this.y;
}
public void paint(Graphics g){
g.setColor(Color.WHITE);
g.fillOval(x, y, 20, 20);
}
public void Collision(Player player){
if(this.x > (player.getX()-10)){
if(this.y > player.getY() && (this.y < player.getY() + player.getH())){
xv = -10;
}
}
}
public void Collision(Computer cpu){
if(this.x < (cpu.getX()+10)){
if(this.y > cpu.getY() && (this.y < cpu.getY() + cpu.getH())){
xv = 10;
}
}
}
}
Computer class:
import java.awt.*;
public class Computer {
private int y = 300;
private int w = 20;
private int h = 120;
private int yv = 0;
private int x = 100;
Ball ballpos = new Ball();
public Computer(){
}
public void update(){
if(ballpos.getY() < this.y){
yv = -1;
}
else if(ballpos.getY() > this.y){
yv = 1;
}
y = y + yv;
}
public void paint(Graphics g){
g.setColor(Color.WHITE);
g.fillRect(x,y,w,h);
}
public int getX(){
return this.x;
}
public int getY(){
return this.y;
}
public int getW(){
return this.w;
}
public int getH(){
return this.h;
}
}
I am sorry if this is too much code, but if only send the AI class, you can not see where the problem is I guess. Please help me I do not know why it is not working. Sorry for my bad English.

Your Computer class creates a differrent ball (ballpos) that is never updated and therefore the AI never moves. You need to pass your Ball object from the GamePanel class to the Computers update method:
Computer:
public void update(Ball ball){
if(ball.getY() < this.y){
yv = -1;
}
else if(ball.getY() > this.y){
yv = 1;
}
y = y + yv;
}
GamePanel:
private void update(){
player.update();
ball.update();
ball.Collision(player);
computer.update(ball);
ball.Collision(computer);
}

Java awt Why can I only remove most recent addition to Linked List

I'm creating a space shooter game in Java awt for my college computer science project.
The enemies that I have spawn every 3 seconds via a timer and are added to a LinkedList, and a for loop renders them all.
In the class I have for my player's bullet object, there are if statements to check whether the laser comes into the bounds of an enemy, and if they are all true it removes the enemy from the LinkedList.
However, only the most recent addition to the LinkedList is being removed; the bullet passes through the others and nothing happens. This is my first time making a game, and the first time I've ever used a LinkedList, so excuse any misunderstandings.
The controller class controls the enemies, the Laser class is the bullet and the Enemy class is the Enemy object. There's also a player, Main and GUI class.
import java.awt.*;
import java.util.LinkedList;
import java.util.Timer;
import java.util.TimerTask;
public class Controller
{
private LinkedList<Enemy> e = new LinkedList<Enemy>();
Enemy tempEnemy, tempEnemy2
;
Main main;
int refreshSpawn = 3000; //move timer refresh rate
int xpos;
int width;
int ypos;
int height;
Timer spawnTimer = new Timer();
public Controller(Main main)
{
this.main = main;
spawn();
}
public void spawn()
{
spawnTimer.schedule(new TimerTask()
{
public void run() //run method and timer
{
addEnemy(new Enemy(main, (int)(Math.random()*4+2)));
}
}, 0, refreshSpawn);
}
public void render(Graphics g)
{
for(int i = 0; i < e.size(); i++)
{
tempEnemy = e.get(i);
xpos = tempEnemy.getX();
width = tempEnemy.getXsize();
ypos = tempEnemy.getY();
height = tempEnemy.getYsize();
tempEnemy.render(g);
}
}
public void update()
{
for(int i = 0; i < e.size(); i++)
{
tempEnemy2 = e.get(i);
tempEnemy2.move();
}
}
public void addEnemy(Enemy enemy)
{
e.add(enemy);
System.out.println(e.size());
//spawn();
}
public void removeEnemy()
{
e.remove(tempEnemy);
}
public int getX()
{
return xpos;
}
public int getY()
{
return ypos;
}
public int getXsize()
{
return width;
}
public int getYsize()
{
return height;
}
public Enemy getEnemy()
{
return tempEnemy;
}
}
import java.awt.*;
public class Enemy
{
Image ship; //image of enemy ship
int x, y; //ship position
int speed;
public Enemy(Main main, int speed) //constructing enemy
{
this.speed = speed;
ship = main.getImage(main.getDocumentBase(), "enemyShip"+(int)(Math.random()*6+1)+".png"); //picture for enemy ship
x = (int)(Math.random()*900+1); //enemy has a starting position at a random x point
y = -100; //start ship slightly off screen so it doesn't suddenly appear
}
public void move()
{
y += speed;
if(y > 600)
{
y = -100;
x = (int)(Math.random()*900);
}
}
public void render(Graphics g)
{
g.drawImage(ship, x, y, null);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public int getXsize()
{
return ship.getWidth(null);
}
public int getYsize()
{
return ship.getHeight(null);
}
}
import java.awt.*;
public class Laser
{
Image img; //image of laser
int laserSpeed = 10; //speed of laser
int x, y; //position of laser
int xSize, ySize; //size of laser
Controller cont;
GUI gui;
public Laser(Image img, int x, int y, Controller cont, GUI gui) //constructing laser
{
this.cont = cont;
this.img = img; //setting laser image
this.gui = gui;
xSize = x; //size of laser
ySize = y; //size of laser
}
public void shoot(int x, int y, int shipSize)
{
this.x = x + (shipSize/2) - (xSize/2);
this.y = y;
}
public void move()
{
y -= laserSpeed;
if(x <= cont.getX() + cont.getXsize() && x + xSize >= cont.getX() - cont.getXsize())
{
if(y <= cont.getY() + cont.getYsize() && y > 0)
{
remove();
cont.removeEnemy();
gui.scoreUp(5);
}
}
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public int getXSize()
{
return xSize;
}
public int getYSize()
{
return ySize;
}
public Image getImage()
{
return img;
}
public void remove()
{
y = -ySize;
x = -100;
}
}

From what I can tell, tempEnemy is assigned to the last element in the LinkedList by the render method. This means that when you call removeEnemy it is removing the last rendered object (likely the last object you added).
What you should be doing is telling the Controller which Enemy it should be using, it has absolutely no idea what your intentions are when you call it...

Java call function in a loop without stackoverflowerror

I know I have asked a question like this before, but none of the answers in the old question worked for me. I am trying to make a little single-player pong game (It is in a Java applet). I already have a moveBall() function, as you can see below. But I don't know where to call it. I can't call it in the paint() method because it is double buffered.
public class Main extends Applet implements KeyListener, MouseListener {
private Rectangle paddle;
private Rectangle ball;
private ArrayList<Integer> keysDown;
private Image dbImage;
private Graphics dbg;
public int time = 300000;
Random randomGenerator = new Random();
int speed = 10;
int level = 1; // change to 0 once start menu works
int xpos, ypos;
int ballx, bally;
int width = 1024;
int height = 768;
int paddleWidth = 96;
int ballSize = 16;
String version = "0.0.1";
public static final int START_X_POS = 160;
public static final int START_Y_POS = 160;
public static final int START_WIDTH = 256;
public static final int START_HEIGHT = 64;
boolean startClicked;
boolean falling = true;
public void init() {
setSize(width, height);
addKeyListener(this);
addMouseListener(this);
setBackground(Color.black);
Frame c = (Frame)getParent().getParent();
c.setTitle("Asteroid Attack - Version " + version);
keysDown = new ArrayList<Integer>();
paddle = new Rectangle(getWidth()/2-paddleWidth, getHeight()-96, paddleWidth, 12);
ball = new Rectangle(getWidth()/2-ballSize, 96, ballSize, ballSize);
}
public void update(Graphics g) {
dbImage = createImage(getSize().width, getSize().height);
dbg = dbImage.getGraphics ();
if (dbImage == null) {}
dbg.setColor(getBackground ());
dbg.fillRect(0, 0, getSize().width, getSize().height);
dbg.setColor(getForeground());
paint(dbg);
g.drawImage(dbImage, 0, 0, this);
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D)g;
if (level != 0) {
g2.setPaint(Color.gray);
g2.fill(paddle);
g2.setPaint(Color.darkGray);
g2.fill(ball);
moveBall();
}
}
public void moveBall() {
bally = ball.y;
ballx = ball.x;
if (bally < paddle.y-32 && falling) {
bally += 12;
}
if (bally < paddle.y-32 && falling && paddle.x <= ballx && paddle.getMaxX() >= ball.x) { // collides with paddle
falling = false;
}
else { // does not collide with paddle
}
ball.setLocation(ballx, bally);
}
#Override
public void keyPressed(KeyEvent e) {
if (!keysDown.contains(e.getKeyCode()))
keysDown.add(new Integer(e.getKeyCode()));
key();
}
#Override
public void keyReleased(KeyEvent e) {
keysDown.remove(new Integer(e.getKeyCode()));
}
public void key() {
if (level != 0) {
int x = paddle.x;
int y = paddle.y;
if (keysDown.contains(KeyEvent.VK_ESCAPE)) {System.exit(0);}
if (x > 0 && x+paddleWidth < this.getWidth()) {
if (keysDown.contains(KeyEvent.VK_LEFT)) {x -= speed;}
if (keysDown.contains(KeyEvent.VK_RIGHT)) {x += speed;}
}
else { // so paddle doesn't exit room
if (x <= 0) {x += 4;}
else {x -= 4;}
}
paddle.setLocation(x, y);
repaint();
}
}
#Override
public void keyTyped(KeyEvent e) {}
#Override
public void mouseClicked(MouseEvent me) {
if (level == 0) {
xpos = me.getX();
ypos = me.getY();
if (xpos >= START_X_POS && ypos >= START_Y_POS && xpos <= START_X_POS + START_WIDTH && ypos <= START_X_POS + START_HEIGHT ) {
level = 1;
}
}
}
#Override
public void mouseEntered(MouseEvent me) {}
#Override
public void mouseExited(MouseEvent me) {}
#Override
public void mouseReleased(MouseEvent me) {}
#Override
public void mousePressed(MouseEvent me) {}
}
Any help would be greatly appreciated!

You'll probably want a separate Thread to move the ball which keeps track of time while in a in a loop - that way if frame rates drop, or speed up, you can try ensure consistency in the ball movement speed.
e.g. here on using a thread in a applet http://www.realapplets.com/tutorial/threadexample.html