I need to make a system where a obstacle is drawn on the screen, when it scrolls off the screen, another one will be drawn at a random value (up to a max of a certain value) on the screen after that one.
I have some code here:
public int xElapsed = 0;
this is just incremented all the time, it is how much the player has moved.
obstacleHole.paint(g);
if(obstacleHole.getX() <= 0){
obstacleHole.paint(g);
}
This is the paint function. The first obstacle is painted straight away, and the second after that condition is met. This is not working as intended, however.
x = position.nextInt(500 + player.xElapsed * 2);
and this is how the x coordinate of the obstacle is set. "position" is a random value generator.
This code is not working because only one obstacle ever shows up. How can I fix this to work as intended? I can provide extra code if necessary.
Here is the ObstacleHole class:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Random;
public class ObstacleHole {
Player player = new Player();
Random position = new Random();
int x;
int y;
int dx = 1;
int width = 100;
int height = 100;
public ObstacleHole(){
x = position.nextInt(500 + player.xElapsed * 2);
y = 250;
}
public void move(){
x = x - player.playerSpeed;
}
public void paint(Graphics g){
g.setColor(Color.BLACK);
g.fillRect(x, y, width, height);
}
public Rectangle bounds(){
return (new Rectangle(x, y, width, height));
}
public int getX() {
return x;
}
}
Screen.java
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Screen extends JPanel implements ActionListener, KeyListener{
Player player = new Player();
ObstacleHole obstacleHole = new ObstacleHole();
public Screen(){
addKeyListener(this);
setDoubleBuffered(true);
setFocusable(true);
Timer tick = new Timer(5, this);
tick.start();
}
public void actionPerformed(ActionEvent e) {
repaint();
player.move();
obstacleHole.move();
System.out.println(player.getXElapsed());
}
public void paint(Graphics g){
super.paint(g);
player.paint(g);
obstacleHole.paint(g);
if(obstacleHole.getX() <= 0){
obstacleHole.paint(g);
}
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if(player.jumpReady){
if(key == KeyEvent.VK_UP){
player.dy = -1;
player.jumpReady = false;
}
}
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
}
Player.java
import java.awt.Color;
import java.awt.Graphics;
public class Player {
int x;
int y;
int dx;
public int xElapsed = 0;
public int dy;
int width = 64;
int height = 64;
public int playerSpeed = 3;
public boolean isMoving = true;
public boolean hasJumped = false;
public boolean jumpReady = true;
public Player(){
x = 150;
y = 250;
}
public void move(){
x = x + dx;
y = y + dy;
xElapsed++;
if(hasJumped == true){
dy = -1;
}
if(y == 150){
dy = 1;
}
if(y == 250){
dy = 0;
jumpReady = true;
}
}
public void paint(Graphics g){
g.setColor(Color.RED);
g.fillRect(x, y, width, height);
}
public int getX(){
return x;
}
public int getY(){
return y;
}
public int getXElapsed(){
return xElapsed;
}
}
In your code you are painting obstacleHole, then when the x value of obstacleHole is less than or equal to 0, you draw it again. All you are doing is sending two calls to the paint() method of the same object.
If you want to paint a second one, you will need to create another object. Or, alternatively, move the original object back onto the screen after it leaves.
It is hard to give you sample code when you have provided so little context, but try something like this:
MyObject obstacleHoleA = new MyObject();
MyObject obstacleHoleB = new MyObject();
obstacleHoleA.paint(g);
if(obstacleHoleA.getX() <= 0){
obstacleHoleB.paint(g);
}
Or this:
obstacleHole.paint(g);
if(obstacleHole.getX() <= 0){
obstacleHole.setX(randomValueUpToAMaxOfCertainValue);
}
Edit: There are a lot of things I would do a lot differently with the above code, but they are outside the scope of the question.
Try this for your ObstacleHole class:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.util.Random;
public class ObstacleHole {
Player player = new Player();
Random position = new Random();
int x;
int y;
int dx = 1;
int width = 100;
int height = 100;
public ObstacleHole(){
x = getNewPosition();
y = 250;
}
public void move(){
x = x - player.playerSpeed;
if(x < 0 - width) {
x = getNewPosition();
}
}
public void paint(Graphics g){
g.setColor(Color.BLACK);
g.fillRect(x, y, width, height);
}
public Rectangle bounds(){
return (new Rectangle(x, y, width, height));
}
public int getX() {
return x;
}
private int getNewPosition() {
return 200 + position.nextInt(300);
}
}
Note the change to the constructor and move() method, along with the new method getNewPosition().
Related
When I add to the GameScreen more than one Object of class Duck only one appears on the screen. When I add Duck outside constructor in GameScreen class I have many Object of Duck but then the mouseClicked method doesn't work on Duck.
Take a look at How to Use BorderLayout. BorderLayout will only present the last component added to any single position.
Having said that, I don't think this is the direction you really want to head in. Instead, start with a single JPanel and override its paintComponent method, then render all you game objects directly through. Components are heavy objects with a lot of complexity and aren't generally well suited for this kind of operation.
Also, you also don't need 3+ threads (Swing Timers make use of a thread to schedule calls back to the UI). Use a single Swing Timer as your "main game loop", which should be responsible for updating the state and scheduling paint passes. Swing is not thread safe, so the use of the Thread to update the label is ill advised.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
BufferedImage img = ImageIO.read(getClass().getResource("/images/Duck.png"));
List<Duck> ducks = new ArrayList<>();
ducks.add(new Duck(img));
ducks.add(new Duck(img));
JFrame frame = new JFrame();
frame.add(new GamePane(ducks));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public class Duck {
private BufferedImage image;
private int x;
private int y;
private int xDelta = 0;
private int yDelta = 0;
public Duck(BufferedImage image) {
this.image = image;
}
public BufferedImage getImage() {
return image;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public void setLocation(int x, int y) {
setX(x);
setY(y);
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
public int getWidth() {
return image == null ? 0 : image.getWidth();
}
public int getHeight() {
return image == null ? 0 : image.getHeight();
}
public void setDelta(int x, int y) {
xDelta = x;
yDelta = y;
}
public int getXDelta() {
return xDelta;
}
public int getYDelta() {
return yDelta;
}
public void move(Rectangle bounds) {
int xDelta = getXDelta();
int yDelta = getYDelta();
int x = getX() + xDelta;
int y = getY() + yDelta;
if (x < bounds.x) {
x = bounds.x;
xDelta *= -1;
} else if (x + getWidth() >= bounds.x + bounds.width) {
x = (bounds.x + bounds.width) - getWidth();
xDelta *= -1;
}
if (y < bounds.y) {
y = bounds.y;
yDelta *= -1;
} else if (y + getWidth() >= bounds.y + bounds.height) {
y = (bounds.y + bounds.height) - getHeight();
yDelta *= -1;
}
setDelta(xDelta, yDelta);
setLocation(x, y);
}
public void paint(Graphics2D g2d, ImageObserver observer) {
g2d.drawImage(getImage(), getX(), getY(), observer);
}
}
public class GamePane extends JPanel {
private List<Duck> ducks;
public GamePane(List<Duck> ducks) {
this.ducks = ducks;
Random rnd = new Random();
for (Duck duck : ducks) {
int width = 400 - duck.getWidth();
int height = 400 - duck.getHeight();
int x = rnd.nextInt(width);
int y = rnd.nextInt(height);
int xDelta = rnd.nextBoolean() ? 1 : -1;
int yDelta = rnd.nextBoolean() ? 1 : -1;
duck.setLocation(x, y);
duck.setDelta(xDelta, yDelta);
}
Timer timer = new Timer(5, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Rectangle bounds = new Rectangle(getSize());
for (Duck duck : ducks) {
duck.move(bounds);
}
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Duck duck : ducks) {
Graphics2D g2d = (Graphics2D) g.create();
duck.paint(g2d, this);
g2d.dispose();
}
}
}
}
From this, you can start adding more entities as needed, for example, I can modify the Main method to include LOTs of ducks...
BufferedImage img = ImageIO.read(getClass().getResource("/images/Duck.png"));
List<Duck> ducks = new ArrayList<>(100);
for (int index = 0; index < 100; index++) {
ducks.add(new Duck(img));
}
This is obviously and overly simplified example intended only as a demonstration of core concept, you'll need to do more research into basic game development and 2D graphics.
I have an assignment to create a 2D game, this game must use an abstract class Shape which is used to draw shapes. I decided to make a 2D platformer, but it's my first time doing something like this. I am trying to implement collision detection, and decided to create an offset of my player object to see if it collides with my rectangle object, and stop movement if it does. This is only working for the top side, however on the right, left and botton the player will move through the rectangle and I don't understand why. I expected the collision detection to work for all sides. I would like to know how I can change my collision detection to work for all sides of the rectangle.
Here's a gif showing what happens:
My App class:
package A2;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.geom.Rectangle2D;
import java.util.TreeSet;
import static java.awt.event.KeyEvent.*;
public class App extends JFrame {
private static final int GRAVITY = 10;
private static final int MAX_FALL_SPEED = 30;
public App() {
final Player player = new Player(200, 300);
final Rectangle rectangle = new Rectangle(100, 400);
JPanel mainPanel = new JPanel() {
public void paintComponent(Graphics g) {
super.paintComponent(g);
player.draw(g);
rectangle.draw(g);
}
};
mainPanel.addKeyListener(new controlHandler(this, player, rectangle));
mainPanel.setFocusable(true);
add(mainPanel);
setLayout(new GridLayout());
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setSize(600, 600);
}
class controlHandler implements ActionListener, KeyListener {
int keyCode;
App app;
Player player;
Rectangle rectangle;
TreeSet<Integer> keys = new TreeSet<>();
Timer time = new Timer(5, this);
boolean collision = false;
public controlHandler(App app, Player player, Rectangle rectangle) {
this.app = app;
this.player = player;
this.rectangle = rectangle;
time.start();
}
public void actionPerformed(ActionEvent e) {
player.x += player.xVelocity;
player.y += player.yVelocity;
Rectangle2D offset = player.getOffsetBounds();
if(offset.intersects(this.rectangle.wallObj.getBounds2D())){
collision = true;
player.xVelocity = 0;
player.yVelocity = 0;
}
else collision = false;
repaint();
}
public void keyPressed(KeyEvent e) {
keyCode = e.getKeyCode();
keys.add(keyCode);
switch (keyCode) {
case VK_UP:
moveUp();
break;
case VK_DOWN:
moveDown();
break;
case VK_LEFT:
moveLeft();
break;
case VK_RIGHT:
moveRight();
break;
}
}
public void keyReleased(KeyEvent e) {
released();
}
public void keyTyped(KeyEvent e) { }
public void moveUp() {
player.xVelocity = 0;
player.yVelocity = -2;
}
public void moveDown() {
if(!collision) {
player.xVelocity = 0;
player.yVelocity = 2;
}
}
public void moveLeft() {
player.xVelocity = -2;
player.yVelocity = 0;
}
public void moveRight() {
player.xVelocity = 2;
player.yVelocity = 0;
}
public void released() {
player.xVelocity = 0;
player.yVelocity = 0;
}
}
public static void main(String[] args) {
App app = new App();
app.setVisible(true);
}
}
abstract class Shape {
public double x;
public double y;
public void draw(Graphics g) { }
}
Player class:
package A2;
import java.awt.*;
import java.awt.geom.Rectangle2D;
public class Player extends Shape {
public double xVelocity;
public double yVelocity;
public double length = 60;
public double top;
public double right;
public double left;
public double bottom;
public Rectangle2D playerObj;
public Player(double x, double y) {
this.x = x;
this.y = y;
playerObj = new Rectangle2D.Double(x, y, length, length);
}
public Rectangle2D getOffsetBounds(){
return new Rectangle2D.Double(x + xVelocity , y + yVelocity , length, length);
}
public void draw(Graphics g) {
playerObj = new Rectangle2D.Double(x, y, length, length);
g.setColor(Color.BLACK);
Graphics2D g2 = (Graphics2D)g;
g2.fill(playerObj);
}
}
Rectangle class (will be a platform):
package A2;
import java.awt.*;
import java.awt.geom.Rectangle2D;
public class Rectangle extends Shape {
public double width = 400;
public double height = 30;
public double top;
public double right;
public double left;
public double bottom;
public Rectangle2D wallObj;
public Rectangle(double x, double y) {
this.x = x;
this.y = y;
wallObj = new Rectangle2D.Double(x, y, width, height);
}
public void draw(Graphics g) {
g.setColor(Color.ORANGE);
Graphics2D g2 = (Graphics2D)g;
g2.fill(wallObj);
}
}
So, based on my understanding, your collision detection process is basically to create a "virtual" instance of the object and determine if it will collide.
Your code is actually work, you can tell by the fact that the object "stops" moving once it collides, but what you're not doing, is reseting the objects position after it.
Let's look at the original code...
public void actionPerformed(ActionEvent e) {
player.x += player.xVelocity;
player.y += player.yVelocity;
Rectangle2D offset = player.getOffsetBounds();
if (offset.intersects(this.rectangle.wallObj.getBounds2D())) {
collision = true;
player.xVelocity = 0;
player.yVelocity = 0;
} else {
collision = false;
}
repaint();
}
Update the position of the object
Create a virtual instance of the object, which applies the velocity to the objects current position ... again?
Determine if the object collides
Stop the movement if any
... where do you reset the position of object so it's no longer colliding?!?
Instead, you shouldn't set the position of the object until AFTER you've determine if a collision has occurred or not, for example...
public void actionPerformed(ActionEvent e) {
Rectangle2D offset = player.getOffsetBounds();
if (offset.intersects(this.rectangle.wallObj.getBounds2D())) {
collision = true;
player.xVelocity = 0;
player.yVelocity = 0;
} else {
player.x += player.xVelocity;
player.y += player.yVelocity;
collision = false;
}
repaint();
}
The problem with this approach, though, is if the velocity is large enough, the object will appear not to collide, but stop a little before it, as the amount of change is larger than the remaining gap.
What you need to do, is once you've detected a collision is calculate the difference between the amount you want to move and the space available and move the object only by that amount instead
I am making a game and tutorials for how to make it on youtube. Here is the link to the channel. I explain the first part of what I have and why I have it because I know that is helpful for filling you in.
Link to part 1(Then watch the rest of parts. #Chris, this is helpful for solving the problem so don't flag the post).
https://www.youtube.com/watch?v=IRn_ZGhJZ94
I noticed as I was testing out my code for part 4. before recording, the game lagged HORRIBLY. I have alot of code, and any help is appreciated.
Game class:
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.Timer;
#SuppressWarnings("serial")
public class Game extends JPanel implements ActionListener{
Timer mainTimer;
Paddle paddle;
Ball ball;
int blockCount = 16;
static ArrayList<Block> blocks = new ArrayList<Block>();
public Game() {
setFocusable(true);
paddle = new Paddle(250, 300);
addKeyListener(new KeyAdapt(paddle));
ball = new Ball(275, 280);
mainTimer = new Timer(10, this);
mainTimer.start();
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/background.png");
g2d.drawImage(ic.getImage(), 0, 0, null);
paddle.draw(g2d);
ball.draw(g2d);
for(int i = 0; i < blockCount; i++) {
Block b = blocks.get(i);
b.draw(g2d);
}
}
#Override
public void actionPerformed(ActionEvent arg0) {
paddle.update();
ball.update();
for(int i = 0; i < blocks.size(); i++) {
Block b = blocks.get(i);
b.update();
}
repaint();
startGame();
}
public void addBlock(Block b) {
blocks.add(b);
}
public static void removeBlock(Block b) {
blocks.remove(b);
}
public static ArrayList<Block> getBlockList() {
return blocks;
}
public void startGame() {
for(int i = 0; i < blockCount; i++) {
addBlock(new Block(i*60 + 7, 20));
addBlock(new Block(i*60 + 7, 0));
}
}
}
Main class(The frame part):
import javax.swing.JFrame;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame("Game");
frame.setSize(500, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new Game());
frame.setResizable(false);
frame.setVisible(true);
}
}
Key Adapt class:
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
public class KeyAdapt extends KeyAdapter{
Paddle p;
public KeyAdapt(Paddle paddle) {
p = paddle;
}
public void keyPressed(KeyEvent e) {
p.keyPressed(e);
}
public void keyReleased(KeyEvent e) {
p.keyReleased(e);
}
}
Paddle class:
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;
public class Paddle {
int velX;
int speed = 3;
static int x1, y1;
public Paddle(int x1, int y1) {
this.x1 = x1;
this.y1 = y1;
}
public void update() {
x1+=velX;
checkCollisions();
}
public void draw(Graphics2D g2d) {
g2d.drawImage(getPaddleImg(), x1, y1, null);
}
public static Image getPaddleImg() {
ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/paddle.png");
return ic.getImage();
}
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if(key==KeyEvent.VK_D) {
velX = speed;
} else if(key==KeyEvent.VK_A){
velX = -speed;
}
}
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if(key==KeyEvent.VK_D) {
velX = 0;
} else if(key==KeyEvent.VK_A){
velX = 0;
}
}
public void checkCollisions() {
if(getBounds().getX() + getBounds().getWidth() >= 500) {
x1 = 440;
} else if(getBounds().getX() <= 0) {
x1 = 0;
}
}
public static Rectangle getBounds() {
return new Rectangle(x1, y1 - 1, getPaddleImg().getWidth(null), getPaddleImg().getHeight(null));
}
}
Ball class:
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
public class Ball {
int velX;
int velY;
int speed = 3;
int x, y;
public Ball(int x, int y) {
this.x = x;
this.y = y;
}
public void update() {
x+=velX;
y+=velY;
checkCollisions();
}
public void draw(Graphics2D g2d) {
g2d.drawImage(getBallImg(), x, y, null);
}
public Image getBallImg() {
ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/ball.png");
return ic.getImage();
}
public void checkCollisions() {
for(int i = 0; i < Game.getBlockList().size(); i++) {
Block b = Game.getBlockList().get(i);
if(getBounds().intersects(b.getBounds()) && velX!=-speed) {
velY=speed;
velX =- speed;
Game.removeBlock(b);
}
else if(getBounds().intersects(b.getBounds())) {
velY=speed;
velX = speed;
Game.removeBlock(b);
}
}
if(getBounds().intersects(Paddle.getBounds())) {
velY = -speed;
} else if (getBounds().getY() <= 0 && velX!=speed) {
velY = speed;
velX =- speed;
}else if (getBounds().getY() <= 0 && velX!=-speed) {
velY = speed;
velX = speed;
} else if(getBounds().getY() >= 400) {
JOptionPane.showMessageDialog(null, "You Lost! :( ");
System.exit(0);
}
if(getBounds().getX() <= 0) {
velX = speed;
} else if(getBounds().getX() >= 500 - getBounds().getWidth()) {
velX = -speed;
}
}
public Rectangle getBounds() {
return new Rectangle(x, y, getBallImg().getWidth(null), getBallImg().getHeight(null));
}
}
Block class:
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import javax.swing.ImageIcon;
public class Block {
int x2, y2;
public Block(int x2, int y2) {
this.x2 = x2;
this.y2 = y2;
}
public void update() {
}
public void draw(Graphics2D g2d){
g2d.drawImage(getBlockImg(), x2, y2, null);
}
public static Image getBlockImg() {
ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/block.png");
return ic.getImage();
}
public Rectangle getBounds() {
return new Rectangle(x2, y2, getBlockImg().getWidth(null), getBlockImg().getHeight(null));
}
}
I also have a folder called Eclipse Game on my desktop and I refer to it in my code.
Again, I understand this is alot but any idea with making it lag less is helpful. Also, watching the tutorial (look at the beginning for the link) on making what I have finished so far will help make it less confusing for you to understand how the code works. The game seriously lags so much I cannot play.
There are multiple issues.
The first, as I already mentioned in my comment, is that you're calling startGame() inside your timer action listener:
#Override
public void actionPerformed(ActionEvent arg0) {
paddle.update();
ball.update();
for(int i = 0; i < blocks.size(); i++) {
Block b = blocks.get(i);
b.update();
}
repaint();
startGame();
}
This is adding 3,200 blocks every second to the game, so you don't want that. I think the simplest place to put startGame() is at the end of the game constructor:
public Game() {
setFocusable(true);
paddle = new Paddle(250, 300);
addKeyListener(new KeyAdapt(paddle));
ball = new Ball(275, 280);
mainTimer = new Timer(10, this);
mainTimer.start();
startGame();
}
The other really big problem is that you're constantly reloading the images all the time. For example, look at this snippet:
if(getBounds().intersects(b.getBounds()) && velX!=-speed) {
velY=speed;
velX =- speed;
Game.removeBlock(b);
}
else if(getBounds().intersects(b.getBounds())) {
velY=speed;
velX = speed;
Game.removeBlock(b);
}
That is 4 calls to getBounds(), and if we take a look at that:
return new Rectangle(x2, y2, getBlockImg().getWidth(null), getBlockImg().getHeight(null));
You are loading 2 images which in total is 4*2*blockCount images every 10ms, just for this one method. Instead of loading images all the time, do something like this:
class GameResources {
static Image ballImage;
static Image paddleImage;
static Image blockImage;
// call GameResources.loadResources() at the
// beginning of main() or something
static void loadResources() {
// load all 3 images once here and be done
ballImage = ...;
paddleImage = ...;
blockImage = ...;
}
Then finally, you have an issue with removing items from the list while iterating over it, Ball.checkCollisions:
for(int i = 0; i < Game.getBlockList().size(); i++) {
Block b = Game.getBlockList().get(i);
if(getBounds().intersects(b.getBounds()) && velX!=-speed) {
velY=speed;
velX =- speed;
// removeBlock changes blocks.size()
Game.removeBlock(b);
}
else if(getBounds().intersects(b.getBounds())) {
velY=speed;
velX = speed;
// removeBlock changes blocks.size()
Game.removeBlock(b);
}
}
Instead you need to do something like this:
Iterator<Block> iter = Game.getBlockList().iterator();
while (it.hasNext()) {
Block b = it.next();
if(getBounds().intersects(b.getBounds()) && velX!=-speed) {
velY=speed;
velX =- speed;
// safely removing
it.remove();
}
else if(getBounds().intersects(b.getBounds())) {
velY=speed;
velX = speed;
// safely removing
it.remove();
}
}
And another possible boundary issue in Game.paint:
// using blockCount after possibly
// removing items from the list
// vvvvvvvvvv
for(int i = 0; i < blockCount; i++) {
Block b = blocks.get(i);
b.draw(g2d);
}
For simple iterations like this, you should use for-each:
for(Block b : blocks) {
b.draw(g2d);
}
After all of that the game runs pretty smoothly, except for some type of issue with the key listener which I didn't have time to figure out. I might look at it again after dinner.
edit:
I noticed a lot of other small things, so here is the program fixed up a bit more with my comments.
Some of the classes aren't public anymore just because I had them all in one source file.
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyAdapter;
import java.util.ArrayList;
import java.util.Iterator;
import java.awt.Rectangle;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Dimension;
import java.net.URL;
import javax.imageio.ImageIO;
import java.io.IOException;
import java.io.File;
public class BlockGame {
public static void main(String[] args) {
// Swing program should always begin on the Swing
// thread with a call to invokeLater.
// See https://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
// change this to
// .loadImages();
GameResources.loadInternetImages();
} catch (IOException x) {
x.printStackTrace();
return;
}
JFrame frame = new JFrame("Game");
// frame.setSize(500, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// frame.add(new Game());
// Instead of calling setSize on the JFrame
// directly, set a preferred size on the game
// panel, then call pack() on the JFrame
Game game = new Game();
game.setPreferredSize(new Dimension(500, 400));
frame.add(game);
frame.pack();
frame.setResizable(false);
frame.setVisible(true);
// I started the game here instead
// of in the game loop, so the panel
// is visible and stuff beforehand.
game.startGame();
}
});
}
}
class Game extends JPanel implements ActionListener {
Timer mainTimer;
Paddle paddle;
Ball ball;
// I removed this because it's only ever
// used by startGame.
// int blockCount = 16;
// I changed this to an instance variable
// (not static) and passed the game in to
// update so the game objects can access
// it.
ArrayList<Block> blocks = new ArrayList<Block>();
public Game() {
setFocusable(true);
paddle = new Paddle(250, 300);
addKeyListener(new KeyAdapt(paddle));
ball = new Ball(275, 280);
mainTimer = new Timer(10, this);
// I moved this to the startGame() method
// mainTimer.start();
}
// Swing programs should override paintComponent
// instead of paint.
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// You should create a copy instead of
// directly using the graphics object which
// the component uses.
// This is so any changes you make to it
// don't affect the Swing paint routines.
Graphics2D g2d = (Graphics2D) g.create();
// ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/background.png");
// g2d.drawImage(ic.getImage(), 0, 0, null);
// Painting static resource.
g2d.drawImage(GameResources.backgroundImage, 0, 0, null);
paddle.draw(g2d);
ball.draw(g2d);
// This loop will throw an out of bounds
// exception once the first block is removed.
// vvvvvvvvvv
// for(int i = 0; i < blockCount; i++) {
// Block b = blocks.get(i);
// b.draw(g2d);
// }
// using for each
for (Block b : blocks) {
b.draw(g2d);
}
// Dispose the copied graphics when you're done.
g2d.dispose();
}
#Override
public void actionPerformed(ActionEvent arg0) {
paddle.update(this);
ball.update(this);
// for(int i = 0; i < blocks.size(); i++) {
// Block b = blocks.get(i);
// b.update();
// }
for (Block b : blocks) {
b.update(this);
}
repaint();
// I moved this to main
// startGame();
}
public void addBlock(Block b) {
blocks.add(b);
}
public void removeBlock(Block b) {
blocks.remove(b);
}
public ArrayList<Block> getBlockList() {
return blocks;
}
// I added this method so that the
// ball can access the paddle without
// static variables.
public Paddle getPaddle() {
return paddle;
}
public void startGame() {
// So the method won't be called twice
// and put the game in some unexpected
// state.
if (mainTimer.isRunning()) {
throw new IllegalStateException("game already started");
}
int initialBlockCount = 16;
for(int i = 0; i < initialBlockCount; i++) {
addBlock(new Block(i*60 + 7, 20));
addBlock(new Block(i*60 + 7, 0));
}
mainTimer.start();
}
}
// Generally speaking you should use
// Swing key bindings now, instead of
// key listeners.
//
// Key listeners have problems with
// the focus system: Swing components
// only send out key events when they
// have the focus.
//
// Key bindings don't have this issue.
//
// You can set up key bindings so they
// trigger any time the key is pressed
// in the focused window.
//
// https://docs.oracle.com/javase/tutorial/uiswing/misc/keybinding.html
//
class KeyAdapt extends KeyAdapter {
Paddle p;
public KeyAdapt(Paddle paddle) {
p = paddle;
}
public void keyPressed(KeyEvent e) {
p.keyPressed(e);
}
public void keyReleased(KeyEvent e) {
p.keyReleased(e);
}
}
class Paddle {
int velX;
int speed = 3;
// I changed these from static
// to instance variables.
int x1, y1;
// I added these variables to
// help with the key listener
// logic.
boolean leftPressed, rightPressed;
public Paddle(int x1, int y1) {
this.x1 = x1;
this.y1 = y1;
}
public void update(Game game) {
x1 += velX;
checkCollisions();
}
public void draw(Graphics2D g2d) {
g2d.drawImage(GameResources.paddleImage, x1, y1, null);
}
// public static Image getPaddleImg() {
// ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/paddle.png");
// return ic.getImage();
// }
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
// This logic is a little more robust
// because it handles cases where both
// keys are being held at the same time.
// Also see computeVelX().
if (key == KeyEvent.VK_D) {
leftPressed = true;
// velX = speed;
} else if (key == KeyEvent.VK_A) {
rightPressed = true;
// velX = -speed;
}
computeVelX();
}
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
// This logic is a little more robust
// because it handles cases where both
// keys are being held at the same time.
// Also see computeVelX().
if (key == KeyEvent.VK_D) {
leftPressed = false;
// velX = 0;
} else if (key == KeyEvent.VK_A) {
rightPressed = false;
// velX = 0;
}
computeVelX();
}
public void computeVelX() {
// This way the keys will never
// "stick". If both keys are
// held at the same time, velX
// is just 0 until one of the
// keys is released.
velX = 0;
if (leftPressed) {
velX += speed;
}
if (rightPressed) {
velX -= speed;
}
}
public void checkCollisions() {
// I used a variable instead of calling
// getBounds() repeatedly.
Rectangle bounds = getBounds();
if (bounds.getX() + bounds.getWidth() >= 500) {
x1 = 440;
} else if (bounds.getX() <= 0) {
x1 = 0;
}
}
// I change this from static to an instance method.
public Rectangle getBounds() {
// return new Rectangle(x1, y1 - 1, getPaddleImg().getWidth(null), getPaddleImg().getHeight(null));
int width = GameResources.paddleImage.getWidth(null);
int height = GameResources.paddleImage.getHeight(null);
return new Rectangle(x1, y1 - 1, width, height);
}
}
class Ball {
int velX;
int velY;
int speed = 3;
int x, y;
public Ball(int x, int y) {
this.x = x;
this.y = y;
}
public void update(Game game) {
x += velX;
y += velY;
checkCollisions(game);
}
public void draw(Graphics2D g2d) {
// g2d.drawImage(getBallImg(), x, y, null);
g2d.drawImage(GameResources.ballImage, x, y, null);
}
// public Image getBallImg() {
// ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/ball.png");
// return ic.getImage();
// }
public void checkCollisions(Game game) {
// Using an iterator instead of looping with size()
// directly, because we want to remove items from
// the list while iterating.
// The problem with removing while iterating with
// size() is that once you remove an element, the
// list shifts all the other elements back by 1,
// so on the next iteration of the loop you end
// up skipping an item.
// (Say you remove the element at index 5. Then
// all the elements shift back, so that e.g. the
// element at index 6 is now at index 5. The variable
// i is incremented, so you end up skipping the element
// that was at index 6 before the removal.
Iterator<Block> iter = game.getBlockList().iterator();
Rectangle bounds = getBounds();
while (iter.hasNext()) {
Block b = iter.next();
Rectangle bBounds = b.getBounds();
if (bounds.intersects(bBounds) && velX != -speed) {
velY = speed;
velX =- speed;
// Game.removeBlock(b);
iter.remove();
} else if (bounds.intersects(bBounds)) {
velY = speed;
velX = speed;
// Game.removeBlock(b);
iter.remove();
}
}
//
Rectangle pBounds = game.getPaddle().getBounds();
if (bounds.intersects(pBounds)) {
velY = -speed;
} else if (bounds.getY() <= 0 && velX != speed) {
velY = speed;
velX =- speed;
} else if (bounds.getY() <= 0 && velX != -speed) {
velY = speed;
velX = speed;
} else if (bounds.getY() >= 400) {
JOptionPane.showMessageDialog(null, "You Lost! :( ");
System.exit(0);
}
if (bounds.getX() <= 0) {
velX = speed;
} else if(bounds.getX() >= 500 - bounds.getWidth()) {
velX = -speed;
}
}
public Rectangle getBounds() {
// return new Rectangle(x, y, getBallImg().getWidth(null), getBallImg().getHeight(null));
int width = GameResources.ballImage.getWidth(null);
int height = GameResources.ballImage.getHeight(null);
return new Rectangle(x, y, width, height);
}
}
class Block {
int x2, y2;
public Block(int x2, int y2) {
this.x2 = x2;
this.y2 = y2;
}
public void update(Game game) {
}
public void draw(Graphics2D g2d){
// g2d.drawImage(getBlockImg(), x2, y2, null);
g2d.drawImage(GameResources.blockImage, x2, y2, null);
}
// public static Image getBlockImg() {
// ImageIcon ic = new ImageIcon("C:/Users/Elliot/Desktop/Eclipse Game/block.png");
// return ic.getImage();
// }
public Rectangle getBounds() {
// return new Rectangle(x2, y2, getBlockImg().getWidth(null), getBlockImg().getHeight(null));
int width = GameResources.blockImage.getWidth(null);
int height = GameResources.blockImage.getHeight(null);
return new Rectangle(x2, y2, width, height);
}
}
class GameResources {
public static Image backgroundImage;
public static Image blockImage;
public static Image ballImage;
public static Image paddleImage;
public static void loadImages() throws IOException {
// Load images once here.
// I didn't test this method since I don't have the images, but it
// should work. ImageIO.read will give better error messages than
// using ImageIcon. ImageIcon.getImage() will just return null if
// there was a problem, which doesn't tell you what the problem
// actually was.
paddleImage =
ImageIO.read(new File("C:/Users/Elliot/Desktop/Eclipse Game/paddle.png"));
ballImage =
ImageIO.read(new File("C:/Users/Elliot/Desktop/Eclipse Game/ball.png"));
blockImage =
ImageIO.read(new File("C:/Users/Elliot/Desktop/Eclipse Game/block.png"));
backgroundImage =
ImageIO.read(new File("C:/Users/Elliot/Desktop/Eclipse Game/background.png"));
}
public static void loadInternetImages() throws IOException {
// These images are from
// http://stackoverflow.com/questions/19209650/example-images-for-code-and-mark-up-qas
paddleImage =
ImageIO.read(new URL("http://i.stack.imgur.com/gYxHm.png"));
ballImage =
ImageIO.read(new URL("http://i.stack.imgur.com/gJmeJ.png"));
blockImage =
ImageIO.read(new URL("http://i.stack.imgur.com/F0JHK.png"));
backgroundImage =
ImageIO.read(new URL("http://i.stack.imgur.com/P59NF.png"));
}
}
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;
}
}
i have looked all over the internet and in my school books but I can't seem to slove my problem.
In my program "bouncing ball" (got the code from our teacher) i need to change the size of the ball from small to bigger and reverse. I understand that i need a boolean to do that and maybe alsow an if statment. This is what I have in the Ball class rigth now regarding the size change:
private boolean changeSize = true;
int maxSize = 10;
int minSize = 1;
public void changeSize(boolean size ){
if(size == maxSize ){
return minSize;
}
else return maxSize;
}
public void changeBallSize(int d, int f){
diameter = d*f;
This is the whole code for the class Ball:
class Ball {
static int defaultDiameter = 10;
static Color defaultColor = Color.yellow;
static Rectangle defaultBox = new Rectangle(0,0,100,100);
// Position
private int x, y;
// Speen and angel
private int dx, dy;
// Size
private int diameter;
// Color
private Color color;
// Bouncing area
private Rectangle box;
// New Ball
public Ball( int x0, int y0, int dx0, int dy0 ) {
x = x0;
y = y0;
dx = dx0;
dy = dy0;
color = defaultColor;
diameter = defaultDiameter;
}
// New color
public void setColor( Color c ) {
color = c;
}
public void setBoundingBox( Rectangle r ) {
box = r;
}
// ball
public void paint( Graphics g ) {
// Byt till bollens färg
g.setColor( color );
g.fillOval( x, y, diameter, diameter );
}
void constrain() {
// Ge absoluta koordinater för det rektangulära området
int x0 = box.x;
int y0 = box.y;
int x1 = x0 + box.width - diameter;
int y1 = y0 + box.height - diameter;
// Setting speed and angels
if (x < x0)
dx = Math.abs(dx);
if (x > x1)
dx = -Math.abs(dx);
if (y < y0)
dy = Math.abs(dy);
if (y > y1)
dy = -Math.abs(dy);
}
// movingt the ball
x = x + dx;
y = y + dy;
constrain();
}
}
I am a total rookie of java! Thanks for the help!
Add the following into your Ball class:
private int changeFlag=-1;
In your constrain() function, just before the last line, after moving the ball:
if(diameter==maxSize) {
changeFlag=-1;
}
else if (diameter==minSize) {
changeFlag=1;
}
diameter=diameter+changeFlag;
Add this code to your Ball Class
private minSize = 1;
private maxSize = 10;
public void setDiameter(int newDiameter) {
this.diameter = newDiameter;
}
public int getMinSize() {
return minSize;
}
public int getMinSize() {
return maxSize;
}
Use this when you use the ball
Ball ball = new Ball(1,1,1,1);
int newDiameter = 10;
if(newDiameter == ball.getMinSize()) {
ball.setDiameter(ball.getMaxSize());
}
id(newDiameter == ball.getMaxSize()) {
ball.setDiameter (ball.getMinSize());
}
I've edited it, is this what you mean?
Main Class:
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
public class Main extends JFrame {
public static void main(String[] args) {
new Main();
}
public Main() {
// configure JFrame
setSize(640, 360);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// create ball
Ball ball = new Ball(this.getWidth()/2, this.getHeight()/2, 50, 100);
add(ball);
Thread t = new Thread(ball);
t.start();
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2 = (Graphics2D) g;
}
}
Ball Class:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.JComponent;
public class Ball extends JComponent implements Runnable {
private int x, y, minDiameter, maxDiameter, currentDiameter, growRate = -1;
private Color color = Color.BLUE;
public Ball(int x, int y, int minDiameter, int maxDiameter) {
this.x = x;
this.y = y;
this.minDiameter = minDiameter;
this.maxDiameter = maxDiameter;
this.currentDiameter = minDiameter;
setVisible(true);
}
#Override
public void run() {
while (true) {
// coerce max and min size
if (this.currentDiameter + growRate > maxDiameter) {
this.currentDiameter = maxDiameter;
this.growRate = -1;
}
if (this.currentDiameter + growRate < minDiameter) {
this.currentDiameter = minDiameter;
this.growRate = 1;
}
this.currentDiameter += this.growRate;
repaint();
try {
Thread.sleep(10);
}
catch(Exception e) {
System.out.println(e.toString());
}
}
}
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
g2.setColor(this.color);
g2.fillOval(this.x, this.y, this.currentDiameter, this.currentDiameter);
}
}