I have been working on a flappy bird clone so I can get more practice programming. Everything in the game works, however the game has frame skips and lag drops, and I do not know how to make Java programs run more smoothly. Am I supposed to measure the amount of time a method takes and try to shorten that, or do I do something else? I have seen people explain how to program Java games, but there is hardly anything on improving the performance. Any advice would be helpful. Thank you.
Hazards class
package entity;
import java.util.ArrayList;
public class Hazards {
public ArrayList<Horizontal> hors;
public ArrayList<Vertical> verts;
public Hazards(int width, int height, int thickness) {
hors = new ArrayList<Horizontal>();
hors.add(new Horizontal(0, 0, width, thickness));
hors.add(new Horizontal(0, height-thickness, width, thickness));
verts = new ArrayList<Vertical>();
}
}
Horizontal class
package entity;
import java.awt.Rectangle;
public class Horizontal {
public int xPos, yPos, width, height;
public Rectangle bounds;
public Horizontal(int x, int y, int w, int h) {
this.xPos = x;
this.yPos = y;
this.width = w;
this.height = h;
this.bounds = new Rectangle(x, y, w, h);
}
public void updateBounds(int x, int y, int w, int h) {
this.xPos = x;
this.yPos = y;
this.width = w;
this.height = h;
this.bounds = new Rectangle(x, y, w, h);
}
}
Vertical class
package entity;
import java.awt.Rectangle;
import java.util.Random;
public class Vertical {
public int xPos, width, gapSize, gapPos;
public boolean scoredOn = false;
public Rectangle top, bottom;
public Vertical(int xPos, int width, int roofHeight, int floorHeight, int gapSize) {
this.xPos = xPos;
this.width = width;
this.gapPos = new Random().nextInt(floorHeight - gapSize) + roofHeight;
this.top = new Rectangle();
this.bottom = new Rectangle();
this.top.setBounds(xPos, 0, width, gapPos);
this.bottom.setBounds(xPos, gapPos + gapSize, width, floorHeight - roofHeight + top.height + gapSize);
}
}
Content class
package main;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Rectangle;
import javax.swing.JPanel;
public class Content extends JPanel {
private static final long serialVersionUID = 1L;
private Engine e;
private Rectangle bounds;
public Content(Engine engine) {
e = engine;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.clearRect(0, 0, this.getWidth(), this.getHeight());
// Roof and floor
g.setColor(Color.black);
for (int x = 0; x < e.e.hors.size(); x++) {
bounds = e.e.hors.get(x).bounds;
g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
}
// Pipes
g.setColor(Color.black);
for(int x = 0; x < e.e.verts.size(); x++) {
bounds = e.e.verts.get(x).top;
g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
bounds = e.e.verts.get(x).bottom;
g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
}
// Player
g.setColor(Color.black);
g.fillRect((int) e.p.xPos, (int) e.p.yPos, e.p.size, e.p.size);
// Score
g.setColor(Color.blue);
g.setFont(new Font("Monospaced", Font.PLAIN, 40));
g.drawString(Integer.toString(e.p.score), e.width/2, 80);
}
}
Engine class
package main;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import entity.Hazards;
import entity.Vertical;
import screen.TitleScreen;
public class Engine implements Runnable {
public JFrame f;
public String title = "Flappy Bird";
public int width = 500, height = 500;
public Content c;
public boolean running = false;
public boolean playing = false;
public Thread t;
public Player p;
public Hazards e;
public TitleScreen ts;
public JPanel mainPanel;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Engine e = new Engine();
e.execute();
}
});
}
public void execute() {
ts = new TitleScreen(width, height);
e = new Hazards(width, height, 30);
p = new Player(this);
c = new Content(this);
c.setPreferredSize(new Dimension(width, height));
c.setLayout(null);
c.addKeyListener(p);
mainPanel = new JPanel();
mainPanel.setPreferredSize(new Dimension(width, height));
mainPanel.setLayout(null);
f = new JFrame();
f.setTitle(title);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setResizable(false);
f.add(c);
// f.add(mainPanel);
f.pack();
f.createBufferStrategy(2);
f.setLayout(null);
f.setLocationRelativeTo(null);
f.setVisible(true);
c.requestFocus();
//ts.setScreen(mainPanel);
start();
}
public synchronized void start() {
if (running)
return;
running = true;
t = new Thread(this);
t.start();
}
public synchronized void stop() {
if (!running)
return;
running = false;
try {
t.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void run() {
long lastime = System.nanoTime();
double AmountOfTicks = 60;
double ns = 1000000000 / AmountOfTicks;
double delta = 0;
int tick = 0;
while (running) {
long now = System.nanoTime();
delta += (now - lastime) / ns;
lastime = now;
if (delta >= 1) {
// Call all updates here
if (playing) {
p.updatePos();
tick++;
if (tick == 60) {
tick = 0;
p.distance += p.speed;
System.out.println(p.distance);
if ((p.distance % 4) == 0) {
System.out.println("Making new pipes-----------------------------------------------------");
e.verts.add(new Vertical(600, 10, 30, height - 30, 100));
}
}
for (int x = 0; x < e.verts.size(); x++) {
e.verts.get(x).top.x -= p.speed;
e.verts.get(x).bottom.x -= p.speed;
if(e.verts.get(x).top.x<-50) {
e.verts.remove(x);
System.out.println("removed a pipe");
}
if(p.xPos>e.verts.get(x).top.x && !e.verts.get(x).scoredOn) {
e.verts.get(x).scoredOn = true;
p.score++;
}
}
}
mainPanel.revalidate();
mainPanel.repaint();
f.revalidate();
f.repaint();
delta--;
}
}
}
}
Player class
package main;
import java.awt.Rectangle;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class Player implements KeyListener {
public int size = 10;
public double xPos = 50;
public double yPos = 240;
public double gravity = 3.4;
public double jumpForce = 16.6;
public double weight = 1;
public int speed = 2;
public int score = 0;
public int distance = 0;
public boolean jumping = false;
public double jumpTime = 10;
public int timed = 0;
public Rectangle bounds, temp, top, bottom;
public Engine en;
public Player(Engine engine) {
en = engine;
bounds = new Rectangle((int)xPos, (int)yPos, size, size);
}
public void keyTyped(KeyEvent e) {
}
public void keyPressed(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_W && en.playing) {
jumping = true;
} else if (e.getKeyCode() == KeyEvent.VK_SPACE) {
en.playing = !en.playing;
}
if(jumping) {
timed = 0;
jumpForce = 16.6;
}
}
public void keyReleased(KeyEvent e) {
}
public void updatePos() {
// collide with floor or ceiling
for(int x = 0; x < en.e.hors.size(); x++) {
temp = en.e.hors.get(x).bounds;
if(bounds.intersects(temp)) {
en.playing = false;
jumping = false;
timed = 0;
jumpForce = 0;
yPos = 240;
score = 0;
en.e.verts.clear();
distance = 0;
gravity = 3.8;
}
}
// collide with pipe
for(int x =0; x <en.e.verts.size();x++) {
top = en.e.verts.get(x).top;
bottom = en.e.verts.get(x).bottom;
if(bounds.intersects(top)||bounds.intersects(bottom)) {
en.playing = false;
jumping = false;
timed = 0;
jumpForce = 0;
yPos = 240;
score = 0;
gravity =3.4;
en.e.verts.clear();
distance = 0;
}
}
if (jumping && en.playing) {
gravity = 3.4;
yPos -= jumpForce;
jumpForce -= weight;
if (jumpForce == 0) {
jumping = false;
jumpForce = 16.6;
}
}
//if(!jumping && en.playing) {
gravity += 0.1;
//}
System.out.println(gravity);
yPos += gravity;
bounds.setBounds((int)xPos, (int)yPos, size, size);
}
}
Related
I am developing a space invaders application for a college assignment and I've come into a problem where the aliens change direction one by one as they hit a wall rather than the whole array of objects switching direction when any alien touches the boundary. I hae a feeling it is an issue in my for loop where my move method containing reverseDirection() method acts on each element individually but I do not know how to fix this and any help would be greatly appreciated. Here is my code for you;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.*;
import javax.swing.*;
import java.awt.image.*;
public class InvadersApplication extends JFrame implements Runnable {//, KeyListener {
private static final Dimension WindowSize = new Dimension(800, 600);
private static final int NUMALIENS = 16;
private Alien AliensArray[] = new Alien[NUMALIENS];
private Image alienImage;
private Image playerImage;
private String workingDirectory = "C:\\Users\\brads\\IdeaProjects\\Assignment3\\src\\workingDirectory\\";
private Player playerShip;
private BufferStrategy strategy;
public InvadersApplication() {
System.out.println(System.getProperty("user.dir"));
setDefaultCloseOperation(EXIT_ON_CLOSE);
Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
int x = screenSize.width / 2 - WindowSize.width / 2;
int y = screenSize.height / 2 - WindowSize.height / 2;
setBounds(x, y, WindowSize.width, WindowSize.height);
this.setTitle("Alien Invaders App");
ImageIcon playerIcon = new ImageIcon(workingDirectory + "player_ship.png");
playerImage = playerIcon.getImage();
ImageIcon alienIcon = new ImageIcon(workingDirectory + "alien_ship_1.png");
alienImage = alienIcon.getImage();
playerShip = new Player(playerImage);
// addKeyListener(this);
setVisible(true);
createBufferStrategy(2);
strategy = getBufferStrategy();
for (int i = 0; i < NUMALIENS; i++) {
AliensArray[i] = new Alien(alienImage);
AliensArray[i].setPosition(70 * (i%4), 70 * (i/4));
AliensArray[i].setXspeed(1);
}
Thread thread1 = new Thread(this);
thread1.start();
repaint();
}
#Override
public void run(){
while(true){
try{
for(int i = 0; i < NUMALIENS; i++) {
AliensArray[i].move();
}
repaint();
Thread.sleep(5);
} catch (Exception e) {
e.printStackTrace();
}
}
}
/* public void keyPressed(KeyEvent e) {
int KeyCode = e.getKeyCode();
if (KeyCode == KeyEvent.VK_LEFT) {
playerShip.movePlayer(-8);
} else if (KeyCode == KeyEvent.VK_RIGHT) {
playerShip.movePlayer(8);
}
}
*/
public void keyReleased(KeyEvent e){
}
public void keyTyped(KeyEvent e){}
public void paint(Graphics g){
g = strategy.getDrawGraphics();
g.setColor(Color.BLACK);
g.fillRect(0,0,800,600);
for(int i=0; i < NUMALIENS; i++){
AliensArray[i].paint(g);
}
// playerShip.paint(g);
//playerShip.paintPlayer(g);
strategy.show();
this.repaint();
}
public static void main(String[] args){
InvadersApplication x = new InvadersApplication();
}
}
Sprite2D class;
public class Sprite2D{
protected int x = 0,y = 30;
protected Image myImage;
public Sprite2D(Image myImage){
this.x = x;
this.y = y;
this.myImage = myImage;
}
public void setPosition(int xx, int yy){
x = xx;
y = yy;
}
public void paint(Graphics g){
g.drawImage(myImage, x,y, null);
}
}
Alien subclass of sprite2D;
import java.awt.*;
import java.util.Random;
import javax.swing.*;
public class Alien extends Sprite2D {
private int xi;
private int xj;
public Alien(Image myImage) {
super(myImage);
this.myImage = myImage;
this.x = x;
this.y = y;
this.xi = xi;
this.xj = xj;
}
// #Override
// public void setPosition(int xx, int yy){
// xx = x;
// yy = y;
//
// }
public void move() {
y+=xj;
x+= xi;
if(x >= 750) {
reverseDirection();
x = x + xi;
}
else if (x < 0)
{
reverseDirection();
x = x + xi;
}
}
public void setXspeed(int xi) {
this.xi = xi;
}
public void setYspeed(int xj) {
this.xj = xj;
}
public void reverseDirection() {
xi = -xi;
System.out.println("reverse");
}
// #Override
// public void paint(Graphics g) {
//
//
// g.drawImage(myImage, xx, yy, null);
// }
}
So I created a simple simple simulation where squares are spawned randomly with random vectors and bounce of the edges of the window.
I wanted it to take into account the window being resized. So that if I change the dimensions of the window from 600x600 to 1200x600 the squares will bounce of the new border rather than 600x600.
I tried doing getWidth() getHeight() but it would return 0.
So I put it in the pain() (since it gets called on window resize) method and saved the return values as local variables. But I cannot call getjpWidth() from the Rect class.
So basically what I need is to get new window dimension into the move() method in the Rect class.
Please feel free to point out any other mistakes and things that can be done better. I'm new to 2D programming (studying Computer Science)
Application
import javax.swing.*;
public class Application {
private Application(){
//create a JFrame window
JFrame frame = new JFrame("Moving Squares");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//add a JPanel
GamePanel gamePanel = new GamePanel();
frame.add(gamePanel);
//pack the window around the content
frame.pack();
//center
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String args[]){
new Application();
}
}
GamePanel
import java.awt.*;
import java.util.ArrayList;
import javax.swing.*;
public class GamePanel extends JPanel implements Runnable{
private int jpWidth=0, jpHeight=0;
//set JPanel size
private static final Dimension DESIRED_SIZE = new Dimension(600,600);
#Override
public Dimension getPreferredSize(){
return DESIRED_SIZE;
}
//constructor
GamePanel(){
Thread t = new Thread(this);
t.start();
}
private ArrayList <Rect> rect=new ArrayList<>();
public void run(){
for(int i=0; i<15; i++){
rect.add(new Rect());
}
while(true){
for(Rect rect:rect){
rect.move();
}
//repaint still image for better frames
//should be 100fps instead it's >144fps
repaint();
try{Thread.sleep(10);}
catch(InterruptedException e){/**/};
repaint();
try{Thread.sleep(10);}
catch(InterruptedException e){/**/};
repaint();
try{Thread.sleep(10);}
catch(InterruptedException e){/**/};
}
}
public void paint(Graphics g){
Graphics2D g2d = (Graphics2D) g.create();
jpWidth=getWidth();
jpHeight=getHeight();
g2d.setColor(Color.white);
g2d.fillRect(0,0,jpWidth,jpHeight);
for(Rect rect:rect) {
g2d.setColor(Color.black);
g2d.fillRect(rect.getXcord()-1, rect.getYcord()-1, rect.getWidth()+2, rect.getHeight()+2);
g2d.setColor(Color.getHSBColor(rect.getR(), rect.getG(), rect.getB()));
g2d.fillRect(rect.getXcord(), rect.getYcord(), rect.getWidth(), rect.getHeight());
}
}
public int getJpWidth() {
return jpWidth;
}
public int getJpHeight() {
return jpHeight;
}
}
Rect
import java.util.Random;
public class Rect {
//properties
private int width=30, height=30;
private int R, G, B;
//movement
private int xCord, yCord;
private int xVector, yVector;
private int xSlope, ySlope;
public Rect(){
Random rand = new Random();
//random color
R=rand.nextInt(255);
G=rand.nextInt(255);
B=rand.nextInt(255);
//random spawn position
xCord=rand.nextInt(600-width);
yCord=rand.nextInt(600-height);
//direction
do{
xVector=rand.nextInt(3) - 1;
yVector=rand.nextInt(3) - 1;
}while(xVector==0 || yVector==0);
//slope
do{
xSlope=rand.nextInt(3);
ySlope=rand.nextInt(3);
}while(xSlope==0 || ySlope==0);
xVector*=xSlope;
yVector*=ySlope;
}
public void move(){
//if(xCord>=//how to get screen width ? ){}
if((xCord>=600-width) || (xCord<=0)){
bounceX();
}
if((yCord>=600-height) || (yCord<=0)) {
bounceY();
}
xCord+=xVector;
yCord+=yVector;
}
public void bounceX(){
xVector*=-1;
}
public void bounceY(){
yVector*=-1;
}
public int getR() {
return R;
}
public int getG() {
return G;
}
public int getB() {
return B;
}
public int getXcord() {
return xCord;
}
public int getYcord() {
return yCord;
}
public int getWidth(){
return width;
}
public int getHeight(){
return height;
}
}
So basically what I need is to get new window dimension into the move() method in the Rect class.
Don't know if it is the best design but I pass the "panel" as a parameter to the "move()" method so its width/height can be used.
Here is some old code I have lying around that shows this approach:
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;
public class BallAnimation4
{
private static void createAndShowUI()
{
BallPanel panel = new BallPanel();
JFrame frame = new JFrame("BallAnimation4");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add( panel );
frame.pack();
frame.setLocationRelativeTo( null );
//frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible( true );
panel.addBalls(5);
panel.startAnimation();
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowUI();
}
});
}
}
class BallPanel extends JPanel implements ActionListener
{
private ArrayList<Ball> balls = new ArrayList<Ball>();
public BallPanel()
{
setLayout( null );
// setBackground( Color.BLACK );
}
public void addBalls(int ballCount)
{
Random random = new Random();
for (int i = 0; i < ballCount; i++)
{
Ball ball = new Ball();
ball.setRandomColor(true);
ball.setLocation(random.nextInt(getWidth()), random.nextInt(getHeight()));
// ball.setMoveRate(32, 32, 1, 1, true);
ball.setMoveRate(16, 16, 1, 1, true);
// ball.setSize(32, 32);
ball.setSize(64, 64);
balls.add( ball );
}
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
for (Ball ball: balls)
{
ball.draw(g);
}
}
#Override
public Dimension getPreferredSize()
{
return new Dimension(800, 600);
}
public void startAnimation()
{
Timer timer = new Timer(1000/60, this);
timer.start();
}
public void actionPerformed(ActionEvent e)
{
move();
repaint();
}
private void move()
{
for (Ball ball : balls)
{
ball.move(this);
}
}
class Ball
{
public Color color = Color.BLACK;
public int x = 0;
public int y = 0;
public int width = 1;
public int height = 1;
private int moveX = 1;
private int moveY = 1;
private int directionX = 1;
private int directionY = 1;
private int xScale = moveX;
private int yScale = moveY;
private boolean randomMove = false;
private boolean randomColor = false;
private Random myRand = null;
public Ball()
{
myRand = new Random();
setRandomColor(randomColor);
}
public void move(JPanel parent)
{
int iRight = parent.getSize().width;
int iBottom = parent.getSize().height;
x += 5 + (xScale * directionX);
y += 5 + (yScale * directionY);
if (x <= 0)
{
x = 0;
directionX *= (-1);
xScale = randomMove ? myRand.nextInt(moveX) : moveX;
if (randomColor) setRandomColor(randomColor);
}
if (x >= iRight - width)
{
x = iRight - width;
directionX *= (-1);
xScale = randomMove ? myRand.nextInt(moveX) : moveX;
if (randomColor) setRandomColor(randomColor);
}
if (y <= 0)
{
y = 0;
directionY *= (-1);
yScale = randomMove ? myRand.nextInt(moveY) : moveY;
if (randomColor) setRandomColor(randomColor);
}
if (y >= iBottom - height)
{
y = iBottom - height;
directionY *= (-1);
yScale = randomMove ? myRand.nextInt(moveY) : moveY;
if (randomColor) setRandomColor(randomColor);
}
}
public void draw(Graphics g)
{
g.setColor(color);
g.fillOval(x, y, width, height);
}
public void setColor(Color c)
{
color = c;
}
public void setLocation(int x, int y)
{
this.x = x;
this.y = y;
}
public void setMoveRate(int xMove, int yMove, int xDir, int yDir, boolean randMove)
{
this.moveX = xMove;
this.moveY = yMove;
directionX = xDir;
directionY = yDir;
randomMove = randMove;
}
public void setRandomColor(boolean randomColor)
{
this.randomColor = randomColor;
switch (myRand.nextInt(3))
{
case 0: color = Color.BLUE;
break;
case 1: color = Color.GREEN;
break;
case 2: color = Color.RED;
break;
default: color = Color.BLACK;
break;
}
}
public void setSize(int width, int height)
{
this.width = width;
this.height = height;
}
}
}
Also, note that for animation you should be using a Swing Timer to schedule the animation. Updates to Swing components should be done on the Event Dispatch Thread (EDT). While not likely to cause a problem with this simple application it is a good habit to make sure this basic rule is followed otherwise you can have random problems and it is never easy to debug a random problem.
I have an error it everytime I try to start it, it comes up with a blank window and these error messages.
Exception in thread "Thread-2" java.lang.IllegalArgumentException: Color parameter outside of expected range: Red Green
at java.awt.Color.testColorValueRange(Unknown Source)
at java.awt.Color.<init>(Unknown Source)
at java.awt.Color.<init>(Unknown Source)
at java.awt.Color.<init>(Unknown Source)
at com.tutorial.main.HUD.render(HUD.java:32)
at com.tutorial.main.Game.render(Game.java:118)
at com.tutorial.main.Game.run(Game.java:85)
at java.lang.Thread.run(Unknown Source)
I have a suspicion it is something to do with rendering but not sure can someone help.
I have inserted the following codes:
Game
Window
SmartEnemy
HUD
ID
Handler
package com.tutorial.main;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.util.Random;
public class Game extends Canvas implements Runnable {
private static final long serialVersionUID = 7580815534084638412L;
public static final int WIDTH = 640, HEIGHT = WIDTH / 12 * 9;
private Thread thread;
private boolean running = true;
private Random r;
private Handler handler;
private HUD hud;
private Spawn spawner;
public Game() {
new Window(WIDTH, HEIGHT, "Lets Build a Game!", this);
handler = new Handler();
hud = new HUD();
spawner = new Spawn(handler, hud);
this.addKeyListener(new KeyInput(handler));
r = new Random();
// for(int i = 0; i <1; i++){
//implementing Player1
handler.addObject(new Player(WIDTH / 2 - 32, HEIGHT / 2 - 32, ID.Player, handler));
handler.addObject(new BasicEnemy(r.nextInt(Game.WIDTH), r.nextInt(Game.HEIGHT), ID.BasicEnemy, handler));
//implementing Player2
//handler.addObject(new Player(WIDTH/2-32, HEIGHT/2+64, ID.Player2));
/*for (int i = 0; i < 1; i++){
//implementing BasicEnemy
handler.addObject(new BasicEnemy(r.nextInt(WIDTH), r.nextInt(HEIGHT), ID.BasicEnemy, handler));
}*/
}
public synchronized void start() {
thread = new Thread(this);
thread.start();
}
public synchronized void stop() {
try {
thread.join();
running = false;
} catch (Exception e) {
e.printStackTrace();
}
}
public void run() {
this.requestFocus();
long lastTime = System.nanoTime();
double amountOfTicks = 60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
long timer = System.currentTimeMillis();
int frames = 0;
while (running) {
long now = System.nanoTime();
delta += (now - lastTime) / ns;
lastTime = now;
while (delta >= 1) {
tick();
delta--;
}
if (running) {
render();
frames++;
if (System.currentTimeMillis() - timer > 1000) {
timer += 1000;
//System.out.println("FPS: " + frames);
frames = 0;
}
}
}
}
private void tick() {
handler.tick();
hud.tick();
spawner.tick();
}
private void render() {
BufferStrategy bs = this.getBufferStrategy();
if (bs == null) {
this.createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.setColor(Color.BLACK);
g.fillRect(0, 0, WIDTH, HEIGHT);
handler.render(g);
hud.render(g);
g.dispose();
bs.show();
}
public static float clamp(float
var, float min, float max) {
if (var >= max) {
return var = max;
} else if (var <= min) {
return var = min;
} else {
return var;
}
}
public static void main(String args[]) {
Game game = new Game();
game.start();
}
}
package com.tutorial.main;
import java.awt.Canvas;
import javax.swing.*;
import java.awt.Dimension;
public class Window extends Canvas {
private static final long serialVersionUID = -240840600533728354L;
public Window(int width, int height, String title, Game game) {
JFrame frame = new JFrame(title);
frame.setPreferredSize(new Dimension(width, height));
frame.setMinimumSize(new Dimension(width, height));
frame.setMaximumSize(new Dimension(width, height));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.add(game);
frame.setVisible(true);
}
}
package com.tutorial.main;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
public class SmartEnemy extends GameObject{
private Handler handler;
private GameObject player;
public SmartEnemy(int x, int y, ID id, Handler handler) {
super(x, y, id);
this.handler = handler;
for(int i = 0; i < handler.object.size(); i++){
if(handler.object.get(i).getId() == ID.Player) player = handler.object.get(i);
}
}
public Rectangle getBounds(){
return new Rectangle((int)x, (int)y, 32, 32);
}
public void tick() {
handler.addObject(new Trail(x, y,ID.Trail, Color.GREEN, 16, 16, 0.02f, handler));
x += velX;
y += velY;
float diffX = x - player.getX() - 8;
float diffY = y - player.getY() - 8;
float distance = (float) Math.sqrt((x - player.getX()) * (x - player.getX()) + (y - player.getY()) * (y - player.getY()));
velX = (float) ((-1.0/distance) * diffX);
velY = (float) ((-1.0/distance) * diffY);
if (y <= 0 || y >= Game.HEIGHT - 37) velY *= -1;
if (x <= 0 || x >= Game.WIDTH - 16) velX*= -1;
}
public void render(Graphics g) {
g.setColor(Color.GREEN);
g.fillRect((int)x, (int)y, 16, 16);
}
}
package com.tutorial.main;
import java.awt.Graphics;
import java.util.LinkedList;
public class Handler {
LinkedList < GameObject > object = new LinkedList < GameObject > ();
public void tick() {
for (int i = 0; i < object.size(); i++) {
GameObject tempObject = object.get(i);
tempObject.tick();
}
};
public void render(Graphics g) {
for (int i = 0; i < object.size(); i++) {
GameObject tempObject = object.get(i);
tempObject.render(g);
}
}
public void addObject(GameObject object) {
this.object.add(object);
}
public void removeObject(GameObject object) {
this.object.remove(object);
}
}
package com.tutorial.main;
import java.awt.Color;
import java.awt.Graphics;
public class HUD {
public static float HEALTH = 100;
private float greenValue = 255;
private int level = 1;
private float score = 0;
public void tick(){
HEALTH = Game.clamp(HEALTH, 0, 100);
greenValue = Game.clamp(greenValue, 0, 255);
greenValue = HEALTH*2;
score++;
}
public void render(Graphics g){
//Background for Health bar
g.setColor(Color.gray);
g.fillRect(15, 15, 200, 32);
//Health Bar
g.setColor(new Color(75, (float) greenValue, 0));
g.fillRect(15, 15, (int) (HEALTH * 2), 32);
g.setColor(Color.WHITE);
g.drawRect(15, 15, 200, 32);
g.drawString("Score: " + score, 15, 60);
g.drawString("Level: " + level, 15, 75);
}
/*int level = 1, point = 0;
//point scoring system
for(int i = 2; i > 1; i++){
if(HEALTH > 0){
point++;
System.out.println(point);
}
}
}*/
private void score(float score){
this.score = score;
}
public float getScore(){
return score;
}
public int getLevel(){
return level;
}
public void setLevel(int level){
this.level = level;
}
}
package com.tutorial.main;
import java.awt.Graphics;
import java.awt.Rectangle;
public abstract class GameObject {
protected float x, y;
protected ID id;
protected float velX, velY;
public GameObject(float x, float y, ID id){
this.x = x;
this.y = y;
this.id = id;
}
public abstract void tick();
public abstract void render(Graphics g);
public abstract Rectangle getBounds();
public void setX(int x){
this.x = x;
}
public void setY(int y){
this.y = y;
}
public int getX(){
return (int) x;
}
public int getY(){
return (int) y;
}
public void setId(ID id){
this.id = id;
}
public ID getId(){
return id;
}
public void setVelX(int velX){
this.velX = velX;
}
public void setVelY(int velY){
this.velY = velY;
}
public float getVelX(){
return velX;
}
public float getVelY(){
return velY;
}
}
The excetion is caused by this constructor call:
new Color(75, (float) greenValue, 0)
You use the Color(float, float, float), since the second parameter has type float. As documented in the javadocs, this constructor takes 3 floats that represent rgb components. Ranges are from 0.0f to 1.0f, not from 0 to 255, which is why you get the error (75 is too large).
It seems like you should not cast the second parameter to make that statement use the Color(int, int, int) constructor.
I created a class that draws a ball on a screen and my goal is to move it with the keys, but the ball stays in one spot. the coordinates of the ball change according to the key presses but not the actual ball itself
import java.applet.Applet;
import java.awt.Color;
import java.awt.Component;
import java.awt.Event;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.concurrent.TimeUnit;
public class game extends Applet implements Runnable
{
static final int WIDTH = 450;
static final int HEIGHT = 450;
private Image dbImage;
private Graphics dbg;
public static long NEW_DOT_FREQ = TimeUnit.SECONDS.toMillis(3);
public long lastUpdateTime;
public long timeSinceLastNewDot;
public ArrayList<Ball> BALLS;
Color[] color = {Color.red, Color.blue, Color.green, Color.yellow, Color.magenta, Color.black};
int colorIndex;
static final int NUM_OF_BALLS = 4;
int i;
int t;
MainBall mainBall = new MainBall(100, 100, 10, 10, 100, 100, 0, 0);
Thread updateTime = new updateTime();
public void start()
{
lastUpdateTime = System.currentTimeMillis();
Thread th = new Thread(this);
th.start();//start main game
updateTime.start();
}
public void updateGame()
{
//Get the current time
long currentTime = System.currentTimeMillis();
//Calculate how much time has passed since the last update
long elapsedTime = currentTime - lastUpdateTime;
//Store this as the most recent update time
lastUpdateTime = currentTime;
//Create a new dot if enough time has passed
//Update the time since last new dot was drawn
timeSinceLastNewDot += elapsedTime;
if (timeSinceLastNewDot >= NEW_DOT_FREQ)
{
int newX = randomNumber();
int newY = randomNumber();
debugPrint("New dot created at x:" + newX + ", y:" + newY + ".");
BALLS.add(new Ball(newX, newY, 20, 20));
timeSinceLastNewDot = 0;
}
}
private void debugPrint(String value)
{
System.out.println(value);
}
public class updateTime extends Thread implements Runnable
{
public void run()
{
for(t = 0; ; t++)
{
try
{
Thread.sleep(1000);
}
catch(InterruptedException e){}
}
}
}
public int randomNumber()
{
return (int)(Math.random() * 400);
}
public int getRandomColor()
{
return (int)(Math.random() * 6);
}
public class MainBall
{
int x;
int y;
int width;
int height;
int xpos = 100;
int ypos = 100;
int xspeed = 0;
int yspeed = 0;
public MainBall(int x, int y, int width, int height, int xpos, int ypos, int xspeed, int yspeed)
{
this.x = 100;
this.y = 100;
this.width = 10;
this.height = 10;
this.xpos = 100;
this.ypos = 100;
this.xspeed = 0;
this.yspeed = 0;
}
public void paintMainBall(Graphics g)
{
g.setColor(Color.black);
g.fillOval(x, y, width, height);
g.drawString(xpos + ", " + ypos, 20, 40);
}
}//mainBall
class Ball
{
int x;
int y;
int width;
int height;
public Ball(int x, int y, int width, int height)
{
this.x = x;
this.y = y;
this.width = width;
this.height = height;
}//end ball
public void paint(Graphics g)
{
g.setColor(color[getRandomColor()]);
g.fillOval(x, y, width, height);
}//end paint
}//ball class
public void update(Graphics g)//double buffer don't touch!!
{
if(dbImage == null)
{
dbImage = createImage(this.getSize().width, this.getSize().height);
dbg = dbImage.getGraphics();
}
dbg.setColor(getBackground());
dbg.fillRect(0, 0, this.getSize().width, this.getSize().height);
dbg.setColor(getForeground());
paint(dbg);
g.drawImage(dbImage, 0, 0, this);
}
public boolean keyDown (Event e, int key)
{
if(key == Event.LEFT)
{
mainBall.xspeed = -5;
mainBall.yspeed = 0;
}
if(key == Event.RIGHT)
{
mainBall.xspeed = 5;
mainBall.yspeed = 0;
}
if(key == Event.UP)
{
mainBall.yspeed = -5;
mainBall.xspeed = 0;
}
if(key == Event.DOWN)
{
mainBall.yspeed = 5;
mainBall.xspeed = 0;
}
return true;
}
public void run()
{
while(true)
{
repaint();
if (mainBall.xpos < 1)
{
mainBall.xpos = 449;
}
if (mainBall.xpos > 449)
{
mainBall.xpos = 1;
}
if (mainBall.ypos < 1)
{
mainBall.ypos = 449;
}
if (mainBall.ypos > 449)
{
mainBall.ypos = 1;
}
mainBall.ypos += mainBall.yspeed;
mainBall.xpos += mainBall.xspeed;
try
{
Thread.sleep(20);
}
catch(InterruptedException ex){}
}
}
public void init()
{
this.setSize(WIDTH, HEIGHT);
BALLS = new ArrayList<Ball>();
}
public void paint(Graphics g)
{
g.drawString("time: " + t, 20, 20);
mainBall.paintMainBall(g);
for (Ball ball : BALLS)
{
ball.paint(g);
}
updateGame();
}
}
You update the xPos/yPos values of the ball, but never the x/y values
public void paintMainBall(Graphics g) {
System.out.println("PaintMainBall");
g.setColor(Color.RED);
g.fillOval(x, y, width, height);
g.drawString(xpos + ", " + ypos, 20, 40);
}
I'm starting to learn java programming and I think it's cool to learn java through game development. I know how to draw image and listen to a keypress then move that image. But is it possible to make the image move back and forth to the window while the window is listening to a keypress? Like for example, while the image or object(like spaceship) is moving left to right in the window, then if I press space key, a laser will fire at the bottom of the screen( cool huh :D ). But basically I just want to know how to make the image move left to right while the window is listening to a keypress.
I'm thinking that I will add a key listener to my window then fire an infinite loop to move the image. Or do I need to learn about threading so that another thread will move the object?
Please advise.
Many thanks.
Yep, a Swing Timer and Key Bindings would work well. Here's another example (mine) :)
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class AnimationWithKeyBinding {
private static void createAndShowUI() {
AnimationPanel panel = new AnimationPanel(); // the drawing JPanel
JFrame frame = new JFrame("Animation With Key Binding");
frame.getContentPane().add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
#SuppressWarnings("serial")
class AnimationPanel extends JPanel {
public static final int SPRITE_WIDTH = 20;
public static final int PANEL_WIDTH = 400;
public static final int PANEL_HEIGHT = 400;
private static final int MAX_MSTATE = 25;
private static final int SPIN_TIMER_PERIOD = 16;
private static final int SPRITE_STEP = 3;
private int mState = 0;
private int mX = (PANEL_WIDTH - SPRITE_WIDTH) / 2;
private int mY = (PANEL_HEIGHT - SPRITE_WIDTH) / 2;
private int oldMX = mX;
private int oldMY = mY;
private boolean moved = false;
// an array of sprite images that are drawn sequentially
private BufferedImage[] spriteImages = new BufferedImage[MAX_MSTATE];
public AnimationPanel() {
// create and start the main animation timer
new Timer(SPIN_TIMER_PERIOD, new SpinTimerListener()).start();
setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT));
setBackground(Color.white);
createSprites(); // create the images
setupKeyBinding();
}
private void setupKeyBinding() {
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inMap = getInputMap(condition);
ActionMap actMap = getActionMap();
// this uses an enum of Direction that holds ints for the arrow keys
for (Direction direction : Direction.values()) {
int key = direction.getKey();
String name = direction.name();
// add the key bindings for arrow key and shift-arrow key
inMap.put(KeyStroke.getKeyStroke(key, 0), name);
inMap.put(KeyStroke.getKeyStroke(key, InputEvent.SHIFT_DOWN_MASK), name);
actMap.put(name, new MyKeyAction(this, direction));
}
}
// create a bunch of buffered images and place into an array,
// to be displayed sequentially
private void createSprites() {
for (int i = 0; i < spriteImages.length; i++) {
spriteImages[i] = new BufferedImage(SPRITE_WIDTH, SPRITE_WIDTH,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = spriteImages[i].createGraphics();
g2.setColor(Color.red);
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
double theta = i * Math.PI / (2 * spriteImages.length);
double x = SPRITE_WIDTH * Math.abs(Math.cos(theta)) / 2.0;
double y = SPRITE_WIDTH * Math.abs(Math.sin(theta)) / 2.0;
int x1 = (int) ((SPRITE_WIDTH / 2.0) - x);
int y1 = (int) ((SPRITE_WIDTH / 2.0) - y);
int x2 = (int) ((SPRITE_WIDTH / 2.0) + x);
int y2 = (int) ((SPRITE_WIDTH / 2.0) + y);
g2.drawLine(x1, y1, x2, y2);
g2.drawLine(y1, x2, y2, x1);
g2.dispose();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(spriteImages[mState], mX, mY, null);
}
public void incrementX(boolean right) {
oldMX = mX;
if (right) {
mX = Math.min(getWidth() - SPRITE_WIDTH, mX + SPRITE_STEP);
} else {
mX = Math.max(0, mX - SPRITE_STEP);
}
moved = true;
}
public void incrementY(boolean down) {
oldMY = mY;
if (down) {
mY = Math.min(getHeight() - SPRITE_WIDTH, mY + SPRITE_STEP);
} else {
mY = Math.max(0, mY - SPRITE_STEP);
}
moved = true;
}
public void tick() {
mState = (mState + 1) % MAX_MSTATE;
}
private class SpinTimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
tick();
int delta = 20;
int width = SPRITE_WIDTH + 2 * delta;
int height = width;
// make sure to erase the old image
if (moved) {
int x = oldMX - delta;
int y = oldMY - delta;
repaint(x, y, width, height);
}
int x = mX - delta;
int y = mY - delta;
// draw the new image
repaint(x, y, width, height);
moved = false;
}
}
}
enum Direction {
UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT);
private int key;
private Direction(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
// Actions for the key binding
#SuppressWarnings("serial")
class MyKeyAction extends AbstractAction {
private AnimationPanel draw;
private Direction direction;
public MyKeyAction(AnimationPanel draw, Direction direction) {
this.draw = draw;
this.direction = direction;
}
#Override
public void actionPerformed(ActionEvent e) {
switch (direction) {
case UP:
draw.incrementY(false);
break;
case DOWN:
draw.incrementY(true);
break;
case LEFT:
draw.incrementX(false);
break;
case RIGHT:
draw.incrementX(true);
break;
default:
break;
}
}
}
Here is another example that uses this sprite sheet:
obtained from this site.
Again it's an example of drawing within a JPanel's paintComponent method and using Key Bindings to tell which direction to move.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.swing.*;
#SuppressWarnings("serial")
public class Mcve3 extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 640;
private static final int TIMER_DELAY = 50;
private int spriteX = 400;
private int spriteY = 320;
private SpriteDirection spriteDirection = SpriteDirection.RIGHT;
private MySprite sprite = null;
private Timer timer = null;
public Mcve3() {
try {
sprite = new MySprite(spriteDirection, spriteX, spriteY);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
setBackground(Color.WHITE);
setKeyBindings(SpriteDirection.LEFT, KeyEvent.VK_LEFT);
setKeyBindings(SpriteDirection.RIGHT, KeyEvent.VK_RIGHT);
setKeyBindings(SpriteDirection.FORWARD, KeyEvent.VK_DOWN);
setKeyBindings(SpriteDirection.AWAY, KeyEvent.VK_UP);
timer = new Timer(TIMER_DELAY, new TimerListener());
timer.start();
}
private void setKeyBindings(SpriteDirection dir, int keyCode) {
int condition = WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition);
ActionMap actionMap = getActionMap();
KeyStroke keyPressed = KeyStroke.getKeyStroke(keyCode, 0, false);
KeyStroke keyReleased = KeyStroke.getKeyStroke(keyCode, 0, true);
inputMap.put(keyPressed, keyPressed.toString());
inputMap.put(keyReleased, keyReleased.toString());
actionMap.put(keyPressed.toString(), new MoveAction(dir, false));
actionMap.put(keyReleased.toString(), new MoveAction(dir, true));
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
sprite.draw(g);
}
private class MoveAction extends AbstractAction {
private SpriteDirection dir;
private boolean released;
public MoveAction(SpriteDirection dir, boolean released) {
this.dir = dir;
this.released = released;
}
#Override
public void actionPerformed(ActionEvent e) {
if (released) {
sprite.setMoving(false);
} else {
sprite.setMoving(true);
sprite.setDirection(dir);
}
}
}
private class TimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
if (sprite.isMoving()) {
sprite.tick();
}
repaint();
}
}
private static void createAndShowGui() {
Mcve3 mainPanel = new Mcve3();
JFrame frame = new JFrame("MCVE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
class MySprite {
private static final String SPRITE_SHEET_PATH = "http://"
+ "orig12.deviantart.net/7db3/f/2010/338/3/3/"
+ "animated_sprite_sheet_32x32_by_digibody-d3479l2.gif";
private static final int MAX_MOVING_INDEX = 4;
private static final int DELTA = 4;
private SpriteDirection direction;
private Map<SpriteDirection, Image> standingImgMap = new EnumMap<>(SpriteDirection.class);
private Map<SpriteDirection, List<Image>> movingImgMap = new EnumMap<>(SpriteDirection.class);
private int x;
private int y;
private boolean moving = false;
private int movingIndex = 0;
public MySprite(SpriteDirection direction, int x, int y) throws IOException {
this.direction = direction;
this.x = x;
this.y = y;
createSprites();
}
public void draw(Graphics g) {
Image img = null;
if (!moving) {
img = standingImgMap.get(direction);
} else {
img = movingImgMap.get(direction).get(movingIndex);
}
g.drawImage(img, x, y, null);
}
private void createSprites() throws IOException {
URL spriteSheetUrl = new URL(SPRITE_SHEET_PATH);
BufferedImage img = ImageIO.read(spriteSheetUrl);
// get sub-images (sprites) from the sprite sheet
// magic numbers for getting sprites from sheet, all obtained by trial and error
int x0 = 0;
int y0 = 64;
int rW = 32;
int rH = 32;
for (int row = 0; row < 4; row++) {
SpriteDirection dir = SpriteDirection.values()[row];
List<Image> imgList = new ArrayList<>();
movingImgMap.put(dir, imgList);
int rY = y0 + row * rH;
for (int col = 0; col < 5; col++) {
int rX = x0 + col * rW;
BufferedImage subImg = img.getSubimage(rX, rY, rW, rH);
if (col == 0) {
// first image is standing
standingImgMap.put(dir, subImg);
} else {
// all others are moving
imgList.add(subImg);
}
}
}
}
public SpriteDirection getDirection() {
return direction;
}
public void setDirection(SpriteDirection direction) {
if (this.direction != direction) {
setMoving(false);
}
this.direction = direction;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public boolean isMoving() {
return moving;
}
public void setMoving(boolean moving) {
this.moving = moving;
if (!moving) {
movingIndex = 0;
}
}
public void tick() {
if (moving) {
switch (direction) {
case RIGHT:
x += DELTA;
break;
case LEFT:
x -= DELTA;
break;
case FORWARD:
y += DELTA;
break;
case AWAY:
y -= DELTA;
}
movingIndex++;
movingIndex %= MAX_MOVING_INDEX;
}
}
public int getMovingIndex() {
return movingIndex;
}
public void setMovingIndex(int movingIndex) {
this.movingIndex = movingIndex;
}
}
enum SpriteDirection {
FORWARD, LEFT, AWAY, RIGHT
}
As an alternative to KeyListener, consider using actions and key bindings, discussed here. Derived from this example, the program below moves a line left, down, up or right using either buttons or keys.
import java.awt.BasicStroke;
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.Point;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
/**
* #see https://stackoverflow.com/questions/6991648
* #see https://stackoverflow.com/questions/6887296
* #see https://stackoverflow.com/questions/5797965
*/
public class LinePanel extends JPanel {
private MouseHandler mouseHandler = new MouseHandler();
private Point p1 = new Point(100, 100);
private Point p2 = new Point(540, 380);
private boolean drawing;
public LinePanel() {
this.setPreferredSize(new Dimension(640, 480));
this.addMouseListener(mouseHandler);
this.addMouseMotionListener(mouseHandler);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.blue);
g2d.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setStroke(new BasicStroke(8,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_BEVEL));
g.drawLine(p1.x, p1.y, p2.x, p2.y);
}
private class MouseHandler extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
drawing = true;
p1 = e.getPoint();
p2 = p1;
repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
drawing = false;
p2 = e.getPoint();
repaint();
}
#Override
public void mouseDragged(MouseEvent e) {
if (drawing) {
p2 = e.getPoint();
repaint();
}
}
}
private class ControlPanel extends JPanel {
private static final int DELTA = 10;
public ControlPanel() {
this.add(new MoveButton("\u2190", KeyEvent.VK_LEFT, -DELTA, 0));
this.add(new MoveButton("\u2191", KeyEvent.VK_UP, 0, -DELTA));
this.add(new MoveButton("\u2192", KeyEvent.VK_RIGHT, DELTA, 0));
this.add(new MoveButton("\u2193", KeyEvent.VK_DOWN, 0, DELTA));
}
private class MoveButton extends JButton {
KeyStroke k;
int dx, dy;
public MoveButton(String name, int code, final int dx, final int dy) {
super(name);
this.k = KeyStroke.getKeyStroke(code, 0);
this.dx = dx;
this.dy = dy;
this.setAction(new AbstractAction(this.getText()) {
#Override
public void actionPerformed(ActionEvent e) {
LinePanel.this.p1.translate(dx, dy);
LinePanel.this.p2.translate(dx, dy);
LinePanel.this.repaint();
}
});
ControlPanel.this.getInputMap(
WHEN_IN_FOCUSED_WINDOW).put(k, k.toString());
ControlPanel.this.getActionMap().put(k.toString(), new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
MoveButton.this.doClick();
}
});
}
}
}
private void display() {
JFrame f = new JFrame("LinePanel");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.add(new ControlPanel(), BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new LinePanel().display();
}
});
}
}
But basically I just want to know how to make the image move left to right while the window is listening to a keypress
You can use a Swing Timer to animate an image:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TimerAnimation extends JLabel implements ActionListener
{
int deltaX = 2;
int deltaY = 3;
int directionX = 1;
int directionY = 1;
public TimerAnimation(
int startX, int startY,
int deltaX, int deltaY,
int directionX, int directionY,
int delay)
{
this.deltaX = deltaX;
this.deltaY = deltaY;
this.directionX = directionX;
this.directionY = directionY;
setIcon( new ImageIcon("dukewavered.gif") );
// setIcon( new ImageIcon("copy16.gif") );
setSize( getPreferredSize() );
setLocation(startX, startY);
new javax.swing.Timer(delay, this).start();
}
public void actionPerformed(ActionEvent e)
{
Container parent = getParent();
// Determine next X position
int nextX = getLocation().x + (deltaX * directionX);
if (nextX < 0)
{
nextX = 0;
directionX *= -1;
}
if ( nextX + getSize().width > parent.getSize().width)
{
nextX = parent.getSize().width - getSize().width;
directionX *= -1;
}
// Determine next Y position
int nextY = getLocation().y + (deltaY * directionY);
if (nextY < 0)
{
nextY = 0;
directionY *= -1;
}
if ( nextY + getSize().height > parent.getSize().height)
{
nextY = parent.getSize().height - getSize().height;
directionY *= -1;
}
// Move the label
setLocation(nextX, nextY);
}
public static void main(String[] args)
{
JPanel panel = new JPanel();
JFrame frame = new JFrame();
frame.setContentPane(panel);
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame.getContentPane().setLayout(null);
// frame.getContentPane().add( new TimerAnimation(10, 10, 2, 3, 1, 1, 10) );
frame.getContentPane().add( new TimerAnimation(300, 100, 3, 2, -1, 1, 20) );
// frame.getContentPane().add( new TimerAnimation(0, 000, 5, 0, 1, 1, 20) );
frame.getContentPane().add( new TimerAnimation(0, 200, 5, 0, 1, 1, 80) );
frame.setSize(400, 400);
frame.setLocationRelativeTo( null );
frame.setVisible(true);
// frame.getContentPane().add( new TimerAnimation(10, 10, 2, 3, 1, 1, 10) );
// frame.getContentPane().add( new TimerAnimation(10, 10, 3, 0, 1, 1, 10) );
}
}
You can add a KeyListener to the panel and it will operate independently of the image animation.