Develop Reference

Java - Create a button from a shape

I am learning Java currently and have been given the assignmnet of finidhing off a program to create the game Conways's life (we started with some code provided to us and must add features etc to this).
I am currently stuck on a menu option for the game. I want it to start off at the menu screen, wherein buttons appear at the top for "Start", "Random", "Load", Save". I have written code so that the program displays these buttons, through a fillRect option in my paint method.
My question is, how do I use the mousePressed method to recognise the cells selected so that I can get an action to occur when they are selected. I been looking at this for a while but can't seem to get this working.
Any suggestion would be a massive help. I have shared my code below. It's a work in progress but I would really like to get this working before continuing on with the other functionality.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.*;
public class ConwaysLife extends JFrame implements Runnable, MouseListener {
// member data
private BufferStrategy strategy;
private Graphics offscreenBuffer;
private boolean gameState[][] = new boolean[40][40];
private boolean isGameInProgress = false;
// constructor
public ConwaysLife () {
//Display the window, centred on the screen
Dimension screensize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
int x = screensize.width/2 - 400;
int y = screensize.height/2 - 400;
setBounds(x, y, 800, 800);
setVisible(true);
this.setTitle("Conway's game of life");
// initialise double-buffering
createBufferStrategy(2);
strategy = getBufferStrategy();
offscreenBuffer = strategy.getDrawGraphics();
// register the Jframe itself to receive mouse events
addMouseListener(this);
// initialise the game state
for (x=0;x<40;x++) {
for (y=0;y<40;y++) {
gameState[x][y]=false;
}
}
// create and start our animation thread
Thread t = new Thread(this);
t.start();
}
// thread's entry point
public void run() {
while ( 1==1 ) {
// 1: sleep for 1/5 sec
try {
Thread.sleep(200);
} catch (InterruptedException e) { }
// 2: animate game objects [nothing yet!]
/*if (isGameInProgress == false) {
this.repaint();
}*/
// 3: force an application repaint
this.repaint();
}
}
// mouse events which must be implemented for MouseListener
public void mousePressed(MouseEvent e) {
while (!isGameInProgress) {
int x = e.getX()/20;
int y = e.getY()/20;
if(x >= 10 && x <= 80 && y >= 40 && y <= 65) {
isGameInProgress = !isGameInProgress;
this.repaint();
}
}
// determine which cell of the gameState array was clicked on
int x = e.getX()/20;
int y = e.getY()/20;
// toggle the state of the cell
gameState[x][y] = !gameState[x][y];
// request an extra repaint, to get immediate visual feedback
this.repaint();
}
public void mouseReleased(MouseEvent e) { }
public void mouseEntered(MouseEvent e) { }
public void mouseExited(MouseEvent e) { }
public void mouseClicked(MouseEvent e) { }
//
// application's paint method
public void paint(Graphics g) {
Font font = new Font("Veranda", Font.BOLD, 20);
g = offscreenBuffer; // draw to off screen buffer
// clear the canvas with a big black rectangle
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 800);
/*look to add a while game in progress loop here!!!*/
// draw menu options
if(!isGameInProgress) {
g.setColor(Color.green);
g.fillRect(10, 40, 70, 25);
g.fillRect(100, 40, 100, 25);
g.fillRect(300, 40, 170, 25);
g.setColor(Color.BLACK);
g.setFont(font);
g.drawString("Start", 15, 60);
g.drawString("Random", 105, 60);
g.drawString("Load", 305, 60);
g.drawString("Save", 395, 60);
}
// redraw all game objects
g.setColor(Color.WHITE);
for (int x=0;x<40;x++) {
for (int y=0;y<40;y++) {
if (gameState[x][y]) {
g.fillRect(x*20, y*20, 20, 20);
}
}
}
// flip the buffers
strategy.show();
}
// application entry point
public static void main(String[] args) {
ConwaysLife w = new ConwaysLife();
}
}

You're not going to like the answer, but it's the "correct" way to approach the problem.
What you need to understand is, Swing/AWT is using a "passive" rendering workflow and BufferStrategy is using a "active" rendering workflow, these are incompatible with each other.
As a general rule, you should not be overriding paint of top level containers like JFrame, this is going to end in no end of issues. Instead, you should be starting with something like JPanel and overriding it's paintComponent method instead.
Having said that, there's a "simpler" solution available to you. CardLayout. This will allow you to seperate the workflows of the menu from the game and resolve the issue between Swing/AWT and BufferStrategy
For example...
import java.awt.Canvas;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferStrategy;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
enum View {
MENU, GAME;
}
private CardLayout cardLayout = new CardLayout();
private GamePane gamePane;
public MainPane() {
setLayout(cardLayout);
gamePane = new GamePane();
add(new MenuPane(new MenuPane.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
}), View.MENU);
add(gamePane, View.GAME);
}
protected void add(Component compent, View view) {
add(compent, view.name());
}
protected void showGame() {
show(View.GAME);
gamePane.start();
}
protected void showMenu() {
gamePane.stop();
show(View.MENU);
}
protected void show(View view) {
cardLayout.show(this, view.name());
}
}
public class MenuPane extends JPanel {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
public MenuPane(Observer observer) {
this.observer = observer;
JButton startButton = new JButton("Start");
JButton randomButton = new JButton("Random");
JButton loadButton = new JButton("Load");
JButton saveButton = new JButton("Save");
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.ipadx = 10;
gbc.ipady = 10;
gbc.insets = new Insets(8, 8, 8, 8);
gbc.weightx = GridBagConstraints.REMAINDER;
add(startButton, gbc);
add(randomButton, gbc);
add(loadButton, gbc);
add(saveButton, gbc);
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.startNewGame();
}
});
randomButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.randomGame();
}
});
loadButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.loadGame();
}
});
saveButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
observer.saveGame();
}
});
}
}
public class GamePane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
public GamePane() {
setBackground(Color.BLACK);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics graphics = strategy.getDrawGraphics();
FontMetrics fm = graphics.getFontMetrics();
String text = "All your game are belong to us";
int x = (getWidth() - fm.stringWidth(text)) / 2;
int y = (getHeight() - fm.getHeight()) / 2;
graphics.setColor(Color.WHITE);
graphics.drawString(text, x, y + fm.getAscent());
// Render to graphics
// ...
// Dispose the graphics
graphics.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
}
I would strongly recommend that you take the time to read through:
Creating a GUI With Swing
A Visual Guide to Layout Managers
Performing Custom Painting
Painting in AWT and Swing
BufferStrategy and BufferCapabilities
JavaDocs for BufferStrategy which demonstrate how the API should be used.
A "fully" BufferStrategy based approach...
Now, if you can't use Swing, "for reasons", you can still achieve a simular concept using "delegation".
Basically this means "delegating" responsibility for performing some workflow to another. In this case, we want to delegate the rendering and the handling of the mouse events.
This allows you to have a dedicated workflow for the menu and a dedicated workflow for the game, without having to try and mix a lot of state.
Why do I keep on insisting on separating these two workflows? Simply, because it makes it MUCH easier to manage and reason about, but also because it supports the Single Responsibility Principle.
The follow example makes use of Renderable interface to define the core functionality that end "render" delegate will need to implement, in this case, it's pretty simple, we want to tell the renderer to "render" it's content on each paint pass and we want to (optionally) delegate mouse clicked events (this could be done via a second interface or even just the MouseListener interface directly, but I've made it a requirement of the Renderable interface for demonstration purposes.
The "basic" solution to your actual question is found through the use of Rectangle#contains(Point).
This basically inspects each "button" Rectangle to determine if the supplied MouseEvent occurs within it's bounds, if it does, we take action.
It is, however, a little more complicated then that, as we need to have the Rectangles built ahead of time, not difficult, but it's state which is actually reliant on the parent, as we need to know the area in which the renderer is been displayed, run the example, you'll see what I mean 😉
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.RoundRectangle2D;
import java.awt.image.BufferStrategy;
import javax.swing.JFrame;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MainPane mainPane = new MainPane();
JFrame frame = new JFrame();
frame.add(mainPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
mainPane.start();
}
});
}
public interface Renderable {
public void render(Graphics2D g2d, Dimension size);
// We could just extend from MouseListener
// but I don't need all those event handlers
public void mouseClicked(MouseEvent e);
}
public class MainPane extends Canvas {
private Thread thread;
private volatile boolean isRunning = false;
private Renderable currentRenderer;
private MenuRenderer menuRenderer;
private GameRenderer gameRenderer;
public MainPane() {
setBackground(Color.BLACK);
gameRenderer = new GameRenderer();
menuRenderer = new MenuRenderer(new MenuRenderer.Observer() {
#Override
public void startNewGame() {
showGame();
}
#Override
public void randomGame() {
}
#Override
public void loadGame() {
}
#Override
public void saveGame() {
}
});
showMenu();
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (currentRenderer == null) {
return;
}
currentRenderer.mouseClicked(e);
}
});
}
protected void showMenu() {
// This may need to tell the game renderer to stop
// or pause
currentRenderer = menuRenderer;
}
protected void showGame() {
currentRenderer = gameRenderer;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
protected void start() {
if (isRunning) {
return;
}
createBufferStrategy(3);
isRunning = true;
thread = new Thread(new Runnable() {
#Override
public void run() {
mainLoop();
}
});
thread.start();
}
protected void stop() {
if (!isRunning || thread == null) {
return;
}
isRunning = false;
try {
thread.join();
} catch (InterruptedException ex) {
}
thread = null;
}
protected void mainLoop() {
try {
while (isRunning) {
render();
Thread.sleep(16);
}
} catch (InterruptedException ex) {
}
}
protected void render() {
BufferStrategy strategy = getBufferStrategy();
if (strategy == null && currentRenderer != null) {
return;
}
// Render single frame
do {
// The following loop ensures that the contents of the drawing buffer
// are consistent in case the underlying surface was recreated
do {
// Get a new graphics context every time through the loop
// to make sure the strategy is validated
Graphics2D g2d = (Graphics2D) strategy.getDrawGraphics();
g2d.setBackground(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
RenderingHints hints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
);
g2d.setRenderingHints(hints);
// Render to graphics
currentRenderer.render(g2d, getSize());
// Dispose the graphics
g2d.dispose();
// Repeat the rendering if the drawing buffer contents
// were restored
} while (strategy.contentsRestored());
// Display the buffer
strategy.show();
// Repeat the rendering if the drawing buffer was lost
} while (strategy.contentsLost());
}
}
public class GameRenderer implements Renderable {
#Override
public void render(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
String text = "All your game are belong to us";
int x = (size.width - fm.stringWidth(text)) / 2;
int y = (size.height - fm.getHeight()) / 2;
g2d.setColor(Color.WHITE);
g2d.drawString(text, x, y + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
}
}
public class MenuRenderer implements Renderable {
public interface Observer {
public void startNewGame();
public void randomGame();
public void loadGame();
public void saveGame();
}
private Observer observer;
private String[] menuOptions = new String[]{
"New Game",
"Random",
"Load Game",
"Save Game"
};
private Rectangle[] menuBounds;
private int internalPadding = 20;
private int horizontalGap = 16;
public MenuRenderer(Observer observer) {
this.observer = observer;
}
#Override
public void render(Graphics2D g2d, Dimension size) {
if (menuBounds == null) {
createMenus(g2d, size);
}
renderMenus(g2d);
}
protected void createMenus(Graphics2D g2d, Dimension size) {
FontMetrics fm = g2d.getFontMetrics();
int totalHeight = (((fm.getHeight() + internalPadding) + horizontalGap) * menuOptions.length) - horizontalGap;
int buttonHeight = fm.getHeight() + internalPadding;
menuBounds = new Rectangle[menuOptions.length];
int buttonWidth = 0;
for (int index = 0; index < menuOptions.length; index++) {
int width = fm.stringWidth(menuOptions[index]) + internalPadding;
buttonWidth = Math.max(width, buttonWidth);
}
int yPos = (size.height - totalHeight) / 2;
for (int index = 0; index < menuOptions.length; index++) {
int xPos = (size.width - buttonWidth) / 2;
Rectangle menuRectangle = new Rectangle(xPos, yPos, buttonWidth, buttonHeight);
menuBounds[index] = menuRectangle;
yPos += buttonHeight + (horizontalGap / 2);
}
}
protected void renderMenus(Graphics2D g2d) {
for (int index = 0; index < menuOptions.length; index++) {
String text = menuOptions[index];
Rectangle bounds = menuBounds[index];
renderMenu(g2d, text, bounds);
}
}
protected void renderMenu(Graphics2D g2d, String text, Rectangle bounds) {
FontMetrics fm = g2d.getFontMetrics();
int textWidth = fm.stringWidth(text);
int textXPos = (bounds.x + (internalPadding / 2)) + ((bounds.width - internalPadding - textWidth) / 2);
int textYPos = bounds.y + (internalPadding / 2);
RoundRectangle2D buttonBackground = new RoundRectangle2D.Double(bounds.x, bounds.y, bounds.width, bounds.height, 20, 20);
g2d.setColor(Color.BLUE.darker());
g2d.fill(buttonBackground);
g2d.setColor(Color.WHITE);
g2d.drawString(text, textXPos, textYPos + fm.getAscent());
}
#Override
public void mouseClicked(MouseEvent e) {
if (menuBounds == null) {
return;
}
for (int index = 0; index < menuOptions.length; index++) {
if (menuBounds[index].contains(e.getPoint())) {
switch (index) {
case 0:
observer.startNewGame();
break;
case 2:
observer.randomGame();
break;
case 3:
observer.loadGame();
break;
case 4:
observer.saveGame();
break;
}
}
}
}
}
}

Swing: How to reduce the response time of MouseInputAdapter?

I've made a tool which could allow user to draw on screenshot.Here is my code:
package GUI.Views;
import javax.swing.*;
import javax.swing.event.MouseInputAdapter;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
public class Canvas extends JPanel {
public static int radius = 5;
public class DrawPointListener extends MouseInputAdapter{
private void draw(Point p, int radius){
Graphics2D g2 = (Graphics2D)getGraphics();
int x = (int)p.getX() - radius/2;
int y = (int)p.getY() - radius/2;
g2.fillOval(x, y, radius, radius);
}
#Override
public void mousePressed(MouseEvent e) {
draw(e.getPoint(), radius);
}
#Override
public void mouseDragged(MouseEvent e) {
draw(e.getPoint(), radius);
}
}
private BufferedImage screenShot;
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(this.screenShot, 0, 0, null);
}
public Canvas() {
this.setVisible(true);
this.screenShot = getScreenShot();
this.setCursor(new Cursor(Cursor.CROSSHAIR_CURSOR));
DrawPointListener drawListener = new DrawPointListener();
this.addMouseListener(drawListener);
this.addMouseMotionListener(drawListener);
}
private BufferedImage getScreenShot() {
try {
return new Robot().createScreenCapture(new Rectangle(Toolkit.getDefaultToolkit().getScreenSize()));
} catch (AWTException e) {
System.out.println("Error");
return null;
}
}
public static void main(String[] args) {
JFrame f = new JFrame();
Canvas canvas = new Canvas();
f.setUndecorated(true);
f.add(canvas);
f.setExtendedState(JFrame.MAXIMIZED_BOTH);
f.setVisible(true);
}
}
Code worked fine when you try to "draw" on the screen slowly, but when you move your mouse quickly, you would see those points are not consecutive, like this:
I think that because there is a time interval of Listener.How could I improve it?

You can't change the time interval of the listener. You are NOT guaranteed to generate an event for every pixel.
So instead of drawing a single point, you need to draw a line between the current and previous point.
Something like:
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.JPanel;
class DrawingPanel extends JPanel
{
private ArrayList<ArrayList<Point>> previous = new ArrayList<ArrayList<Point>>();
private ArrayList<Point> current = new ArrayList<Point>();
private BasicStroke basicStroke;
public DrawingPanel(int strokeSize)
{
basicStroke = new BasicStroke(strokeSize, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
MouseAdapter ma = new MouseAdapter()
{
#Override
public void mousePressed(MouseEvent e)
{
current.add( new Point(e.getX(), e.getY()) );
}
#Override
public void mouseDragged(MouseEvent e)
{
current.add( new Point(e.getX(), e.getY()) );
repaint();
}
#Override
public void mouseReleased(MouseEvent e)
{
if (current.size() > 1)
{
previous.add( current );
}
current = new ArrayList<Point>();
}
};
addMouseMotionListener( ma );
addMouseListener( ma );
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setStroke( basicStroke );
// Paint lines from previous drags
for (int i = 0; i < previous.size(); i++)
{
drawLines(g, previous.get(i));
}
// Paint line from current drag
drawLines(g, current);
}
private void drawLines(Graphics g, ArrayList<Point> points)
{
for (int i = 0; i < points.size() - 1; i++)
{
int x = (int) points.get(i).getX();
int y = (int) points.get(i).getY();
int x2 = (int) points.get(i + 1).getX();
int y2 = (int) points.get(i + 1).getY();
g.drawLine(x, y, x2, y2);
}
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("Drawing Panel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new DrawingPanel(15));
frame.setSize(400, 400);
frame.setLocationByPlatform( true );
frame.setVisible( true );
}
public static void main(String[] args) throws Exception
{
EventQueue.invokeLater( () -> createAndShowGUI() );
/*
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
*/
}
}

Getting my sprite to face in a certain direction based on Keyboard input - Java Game

So I've pretty much thrown together a basic game in java by following a bunch of different tutorials - the problem is i cant manage to figure out how to get my sprite to move in different directions. Here is the code for my main
package com.game.src.main;
import java.awt.Canvas;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import javax.swing.JFrame;
public class Game extends Canvas implements Runnable {
private static final long serialVersionUID = 1L;
public static final int WIDTH = 850;
public static final int HEIGHT = 650;
public static final int SCALE = 1;
public final String TITLE = "Racing Game!";
static ServerSocket serverSocket;
static Socket socket;
static DataOutputStream out;
private boolean running = false;
private Thread thread;
private BufferedImage image = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_RGB);
private BufferedImage spriteSheet = null;
private BufferedImage spriteSheet2 = null;
private BufferedImage background = null;
private BufferedImage MenuBackground = null;
private Player p;
private Player2 p2;
private Menu menu;
public static enum STATE {
MENU,
GAME
};
public static STATE State = STATE.MENU;
public void init() {
BufferedImageLoader loader = new BufferedImageLoader();
try {
spriteSheet = loader.loadImage("/Sprite_Sheet.png");
background = loader.loadImage("/Track.png");
MenuBackground = loader.loadImage("/MenuBG.fw.png");
}
catch (IOException e) {
e.printStackTrace();
}
menu = new Menu();
addKeyListener(new KeyInput(this));
this.addMouseListener(new MouseInput());
p = new Player(365, 500, this);
p2 = new Player2(365, 550, this);
}
private synchronized void start() {
if(running)
return;
running = true;
thread = new Thread(this);
thread.start();
}
private synchronized void stop() {
if(!running)
return;
running = false;
try {
thread.join();
}
catch (InterruptedException e) {
e.printStackTrace();
}
System.exit(1);
}
public void run() {
init();
long lastTime = System.nanoTime();
final double amountOfTicks = 60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
int updates = 0;
int frames = 0;
long timer = System.currentTimeMillis();
while(running) {
long now = System.nanoTime();
delta += (now - lastTime) / ns;
lastTime = now;
if(delta >= 1) {
tick();
updates++;
delta--;
}
render();
frames++;
if(System.currentTimeMillis() - timer > 1000) {
timer += 1000;
System.out.println(updates + " FPS, TICKS " + frames);
updates = 0;
frames = 0;
}
}
stop();
}
private void tick() {
if(State == STATE.GAME){
p.tick();
p2.tick();
}
}
private void render() {
BufferStrategy bs = this.getBufferStrategy();
if(bs == null) {
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
g.drawImage(MenuBackground, 0, 0, null);
if(State == STATE.GAME){
//Drawing the main games background
g.drawImage(background, 0, 0, null);
p.render(g);
p2.render(g);
}
else if(State == STATE.MENU){
menu.render(g);
}
g.dispose();
bs.show();
}
public void keyPressed(KeyEvent e){
int key = e.getKeyCode();
if(State == STATE.GAME){
if(key == KeyEvent.VK_RIGHT){
p.setVelX(5);
}
if(key == KeyEvent.VK_D){
p2.setVelX2(5);
}
else if(key == KeyEvent.VK_LEFT) {
p.setVelX(-5);
}
else if(key == KeyEvent.VK_A) {
p2.setVelX2(-5);
}
else if(key == KeyEvent.VK_DOWN) {
p.setVelY(5);
}
else if(key == KeyEvent.VK_S) {
p2.setVelY2(5);
}
else if(key == KeyEvent.VK_UP) {
p.setVelY(-5);
}
else if(key == KeyEvent.VK_W) {
p2.setVelY2(-5);
}
}
}
public void keyReleased(KeyEvent e){
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT){
p.setVelX(0);
}
if(key == KeyEvent.VK_D){
p2.setVelX2(0);
}
else if(key == KeyEvent.VK_LEFT) {
p.setVelX(0);
}
else if(key == KeyEvent.VK_A) {
p2.setVelX2(0);
}
else if(key == KeyEvent.VK_DOWN) {
p.setVelY(0);
}
else if(key == KeyEvent.VK_S) {
p2.setVelY2(0);
}
else if(key == KeyEvent.VK_UP) {
p.setVelY(0);
}
else if(key == KeyEvent.VK_W) {
p2.setVelY2(0);
}
}
public static void main(String args[]) throws Exception {
Game game = new Game();
game.setPreferredSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
game.setMaximumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
game.setMinimumSize(new Dimension(WIDTH * SCALE, HEIGHT * SCALE));
JFrame frame = new JFrame(game.TITLE);
frame.add(game);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
game.start();
System.out.println("Starting server....");
serverSocket = new ServerSocket(7777);
System.out.println("Server started");
socket = serverSocket.accept();
System.out.println("Connecting from: " + socket.getInetAddress());
out = new DataOutputStream(socket.getOutputStream());
out.writeUTF("This is a test of Java Sockets");
System.out.println("Data has been sent");
}
public BufferedImage getSpriteSheet() {
return spriteSheet;
}
public BufferedImage getSpriteSheet2() {
return spriteSheet2;
}
}
This is my player class
package com.game.src.main;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
public class Player {
private double x;
private double y;
private double velX = 0;
private double velY = 0;
private BufferedImage player;
BufferedImageLoader loader = new BufferedImageLoader();
BufferedImage SpriteSheet = null;
public Player(double x, double y, Game game) {
this.x = x;
this.y = y;
//New instance of Sprite sheet - reading from buffered image loader
SpriteSheet ss = new SpriteSheet(game.getSpriteSheet());
player = ss.grabImage(1, 1, 50, 50);
try {
SpriteSheet = loader.loadImage("/Sprite_Sheet.png");
}
catch(Exception e) {
e.printStackTrace();
}
}
public void tick() {
x+=velX;
y+=velY;
//Adding basic collision
if(x < 0 + 50) {
x = 0 + 50;
}
if(x >= 850 - 100) {
x = 850 - 100;
}
if(y < 0 + 100) {
y = 0 + 100;
}
if(y >= 650 - 100){
y = 650 - 100;
}
}
public void render(Graphics g){
//Draw Track
Color c1 = Color.green;
g.setColor( c1 );
g.fillRect( 150, 200, 550, 300 ); //grass
Color c2 = Color.black;
g.setColor( c2 );
g.drawRect(50, 100, 750, 500); // outer edge
g.drawRect(150, 200, 550, 300); // inner edge
Color c3 = Color.yellow;
g.setColor( c3 );
g.drawRect( 100, 150, 650, 400 ); // mid-lane marker
Color c4 = Color.white;
g.setColor( c4 );
g.drawLine( 425, 500, 425, 600 ); // start line
g.drawImage(player, (int)x, (int)y, null);
}
public double getX(Graphics g){
return x;
}
public double getY(){
return y;
}
public void setX(double x){
this.x = x;
}
public void setY(double y){
this.y = y;
}
public void setVelX(double velX){
this.velX = velX;
}
public void setVelY(double velY){
this.velY = velY;
}
}
I have two players in this game but i'm really stuck on how i can change the sprites direction by 22.5% in a desired direction so if i pressed the up key for player 1 it would rotate my car 22.5% north etc. I have a sprite sheet with 16 sprites for each player for every change in angle by 22.5% This is really confusing me and i'm not sure how i can implement this,
Thanks for taking the time to look

This is a basic example of spinning a sprite
What this is maintain's a virtual state which the Player object inspects in order to determine how it should be changed accordingly. This separates the action from the result, meaning that it would be possible to substitute the action (arrow up key) with some other action, but still obtain the same result.
This example also uses the key bindings API, which doesn't suffer from the same focus related issues that KeyListener does, but this is a pure Swing API and won't be compatiable with Canvas, but is a nice demonstration ;)
The real magic occurs in the characters paint method...
public void paint(Graphics2D g2d) {
Graphics2D g = (Graphics2D) g2d.create();
AffineTransform at = new AffineTransform();
at.translate(x, y);
at.rotate(Math.toRadians(angle), character.getWidth() / 2, character.getHeight() / 2);
g.transform(at);
g.drawImage(character, 0, 0, null);
}
Basically, this creates a AffineTransformation which is then compounded to produce the result we need. That is, first it's anchor position is translated to the characters x/y position and then rotated about the characters center point. Because it's been translated, we can simply paint the character at 0x0. This much easier then try to calculate the characters rotation anchor somewhere else in virtual space - IMHO
The character is rotated by pressing either the Up or Down arrow keys. While pressed, the character will continue to rotate, this is a feature of the example for demonstration purpose.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class RotateCharater {
public static void main(String[] args) {
new RotateCharater();
}
public RotateCharater() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private DefaultState state;
private Player player;
public TestPane() {
player = new Player();
state = new DefaultState();
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, false), "upKeyPressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0, true), "upKeyReleased");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, false), "downKeyPressed");
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0, true), "downKeyReleased");
ActionMap am = getActionMap();
am.put("upKeyPressed", new UpKeyAction(state, true));
am.put("upKeyReleased", new UpKeyAction(state, false));
am.put("downKeyPressed", new DownKeyAction(state, true));
am.put("downKeyReleased", new DownKeyAction(state, false));
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
player.update(state);
repaint();
}
});
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
player.paint(g2d);
g2d.dispose();
}
public class UpKeyAction extends AbstractAction {
private DefaultState state;
private boolean pressed;
public UpKeyAction(DefaultState state, boolean pressed) {
this.state = state;
this.pressed = pressed;
}
#Override
public void actionPerformed(ActionEvent e) {
state.setUpKeyPressed(pressed);
}
}
public class DownKeyAction extends AbstractAction {
private DefaultState state;
private boolean pressed;
public DownKeyAction(DefaultState state, boolean pressed) {
this.state = state;
this.pressed = pressed;
}
#Override
public void actionPerformed(ActionEvent e) {
state.setDownKeyPressed(pressed);
}
}
}
public interface State {
public boolean isUpKeyPressed();
public boolean isDownKeyPressed();
}
public class DefaultState implements State {
private boolean upKeyPressed;
private boolean downKeyPressed;
public boolean isDownKeyPressed() {
return downKeyPressed;
}
public boolean isUpKeyPressed() {
return upKeyPressed;
}
public void setDownKeyPressed(boolean downKeyPressed) {
this.downKeyPressed = downKeyPressed;
upKeyPressed = false;
}
public void setUpKeyPressed(boolean upKeyPressed) {
this.upKeyPressed = upKeyPressed;
downKeyPressed = false;
}
}
public class Player {
private BufferedImage character;
private int x = 100 - 32, y = 100 - 32;
private double angle;
public Player() {
try {
character = ImageIO.read(getClass().getResource("/Character.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
public void paint(Graphics2D g2d) {
Graphics2D g = (Graphics2D) g2d.create();
AffineTransform at = new AffineTransform();
at.translate(x, y);
at.rotate(Math.toRadians(angle), character.getWidth() / 2, character.getHeight() / 2);
g.transform(at);
g.drawImage(character, 0, 0, null);
}
public void update(State state) {
if (state.isUpKeyPressed()) {
angle -= 22.5;
} else if (state.isDownKeyPressed()) {
angle += 22.5;
}
}
}
}
Remember, this is just an example used to present the concept ;)

mouseMoved Event not working

I've been trying to work this code, it's like when you hover over the start button it should change its color to gray, but whenever i hover over it. nothing happens, can somebody tell me why? i didn't get any error and it seems like my mousemoved listener isn't recognized by the compiler, sorry for my english. I haven't finish it yet but here is the code:
class Contents extends JFrame implements Runnable {
private Image dbi;
private Graphics dbg;
private boolean isStarted, isHovered;
private int x,y,xDir,yDir,bx,by,timer,life,my,mx,mhx,mhy;
private Rectangle startgame = new Rectangle(80,100,150,40);
Contents()
{
super();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
if(isStarted)
setSize(600,600);
else
{
setSize(300,300);
setBackground(Color.BLUE);
}
setLocationRelativeTo(null);
isStarted = false;
isHovered = false;
addMouseListener(new MouseAdapter()
{
public void mousePressed(MouseEvent e)
{
mx = e.getX();
my = e.getY();
if(mx > startgame.x && mx < startgame.x+startgame.width &&
my > startgame.y && my < startgame.y+startgame.height)
{
isStarted = true;
}
}
public void mouseMoved(MouseEvent e)
{
mhx = e.getX();
mhy = e.getY();
if(mhx > startgame.x && mhx < startgame.x+startgame.width &&
mhy > startgame.y && mhy < startgame.y+startgame.height)
isHovered = true;
else
isHovered = false;
}
});
}
public void paint(Graphics g)
{
dbi = createImage(getWidth(), getHeight());
dbg = dbi.getGraphics();
draw(dbg);
g.drawImage(dbi,0,0,this);
repaint();
}
public void draw(Graphics g)
{
if(!isStarted)
{
if(!isHovered)
g.setColor(Color.GRAY);
else
g.setColor(Color.GREEN);
g.fillRect(startgame.x, startgame.y, startgame.width, startgame.height);
g.setFont(new Font("Serif",Font.BOLD,24));
g.setColor(Color.WHITE);
g.drawString("Start game", startgame.x+20, startgame.y+25);
g.drawString(String.format("hoverx: %d hovery: %d",mhx,mhy), 50,200);
}
else
{
}
}
public void run()
{
} }
public class Game {
public static void main(String[] args)
{
Contents c = new Contents();
} }

Just use Rectangle.contains(Point) to check if the point from the MouseEvent is inside the Rectangle. Here is an example
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class PaintedButton extends JPanel {
private static final Color HOVER_COLOR = Color.BLUE;
private static final Color NON_HOVER_COLOR = Color.GREEN;
private static final Rectangle2D RECTANGLE = new Rectangle2D.Double(50, 50,
200, 100);
private Color color = NON_HOVER_COLOR;
public PaintedButton() {
addMouseMotionListener(new MouseMotionAdapter() {
public void mouseMoved(MouseEvent e) {
Point p = e.getPoint();
if (RECTANGLE.contains(p)) {
color = HOVER_COLOR;
} else {
color = NON_HOVER_COLOR;
}
repaint();
}
});
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(color);
g2.fill(RECTANGLE);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(300, 200);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new PaintedButton());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

How do I draw the same moving image multiple times?

Hello I'm making a platformer game and when you press space the character shoots a fireball that moves across the screen but when you press space again the fireball's coordinates are set back to the player's coordinates rather than drawing another fireball which is what I want.
import java.awt.*;
import javax.swing.*;
public class Fire extends JPanel{
Image fireball;
private int x=155000,y=155000;
Player player = new Player();
public void paint(Graphics g){
g.drawImage(fireball, x, y, null);
}
public Fire(){
}
public void update(){
fireball = new ImageIcon("C:\\Users\\steven.greens10\\Desktop\\Programs\\Raw Java\\Platform\\res\\fireball.png").getImage();
x+=5;
if(x > 640){
x=155000;
}
}
public void shoot(Player p){
x = p.getX();
y = p.getY();
repaint();
}
}

#KevinWorkman is right. You need some kind of data structure to hold the fireballs. In the example below I used a List of Fireball.
List<Fireball> fireBalls;
...
private class Fireball {
Image fireball;
int x = 150;
int y = 125;
public Fireball(Image image) {
fireball = image;
}
public void drawFireball(Graphics g) {
g.drawImage(fireball, x, y, 50, 50, null);
}
}
To paint them, I just iterate through them. To make them move forward I just increas the x value in the timer and call repaint
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
...
for (Fireball ball : fireBalls) {
ball.drawFireball(g);
}
}
Here's the complete code
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.*;
import java.util.List;
import java.util.logging.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.Timer;
public class WannaBeStreetFighter extends JPanel {
private static final int D_W = 700;
private static final int D_H = 250;
private static final int X_INC = 10;
List<Fireball> fireBalls;
BufferedImage ryu;
BufferedImage fireball;
BufferedImage background;
public WannaBeStreetFighter() {
try {
ryu = ImageIO.read(new URL("http://www.sirlin.net/storage/street_fighter/ryu_hadoken_pose.png?__SQUARESPACE_CACHEVERSION=1226531909576"));
background = ImageIO.read(new URL("http://fightingstreet.com/folders/variousinfofolder/ehondasbath/hondasfz3stage.gif"));
fireball = ImageIO.read(new URL("http://farm6.staticflickr.com/5480/12297371495_ec19ded155_o.png"));
} catch (IOException ex) {
Logger.getLogger(WannaBeStreetFighter.class.getName()).log(Level.SEVERE, null, ex);
}
fireBalls = new LinkedList<>();
Timer timer = new Timer(40, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Iterator<Fireball> it = fireBalls.iterator();
while (it.hasNext()) {
Fireball ball = it.next();
if (ball.x > D_W) {
it.remove();
System.out.println(fireBalls.size());
} else {
ball.x += X_INC;
repaint();
}
}
}
});
timer.start();
InputMap inputMap = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
inputMap.put(KeyStroke.getKeyStroke("SPACE"), "hadouken");
getActionMap().put("hadouken", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
fireBalls.add(new Fireball(fireball));
}
});
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background, 0, 0, D_W, D_H, this);
g.drawImage(ryu, 50, 125, 150, 115, this);
for (Fireball ball : fireBalls) {
ball.drawFireball(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(D_W, D_H);
}
private class Fireball {
Image fireball;
int x = 150;
int y = 125;
public Fireball(Image image) {
fireball = image;
}
public void drawFireball(Graphics g) {
g.drawImage(fireball, x, y, 75, 50, null);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame("Best Street Fighter ever");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new WannaBeStreetFighter());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

Did you try creating another instance of Image? For example:
Image fireball, firball2;
Now you have two Image objects. So when you call g.dawImage(...):
public void paint(Graphics g){
g.drawImage(fireball, x, y, null);
g.drawImage(fireball2, x+10, y+10, null);//just draw this other Image
}
You can just keep drawing multiple images. Also, I changed the x and y positions, so the two Image objects don't overlap.
Now if you want a bunch of Image objects, then use an ArrayList of Image objects:
ArrayList<Image> fireballs = new ArrayList<Image>();
Read more about ArrayList here.