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Grid line collision checking

Lately I've been working on a grid line detection system, I know that there was an algorithm out there that did excactly what I wanted it to do, but I'm that kind of person who wants to make stuff themselves. ;)
So I've had some succes when checking with 1 line, but now that I use a grid of 20x20 to check the lines it doesn't work anymore.
The problem is found somewhere in the collision class I made for this system.
Somehow the numbers get out of the grid array and I don't know why
here is the code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
/**
*
* beschrijving
*
* #version 1.0 van 22-6-2016
* #author
*/
public class gridline extends JApplet {
// Begin variabelen
int[][] grid = new int[20][20];
int[] light = new int[2];
int[][] line = new int[2][2];
// Einde variabelen
public void init() {
Container cp = getContentPane();
cp.setLayout(null);
cp.setBounds(0, 0, 600, 600);
// Begin componenten
for (int a=0; a<20; a++) {
for (int b=0; b<20; b++) {
grid[a][b] = (int) (Math.random()*10);
} // end of for
} // end of for
line[0][0] = (int) (Math.random()*20);
line[0][1] = (int) (Math.random()*20);
line[1][0] = (int) (Math.random()*20);
line[1][1] = (int) (Math.random()*20);
light[0] = (int) (Math.random()*20);
light[1] = (int) (Math.random()*20);
// Einde componenten
} // end of init
//Custom classes
private boolean collide(int x1, int y1,int x2, int y2) {
boolean collide = true;
int tempx = x1 - x2;
int tempy = y1 - y2;
int sx = 0;
int sy = 0;
int x = 0;
int y = 0;
if (tempx == 0) {
tempx = 1;
sx = 1;
} // end of if
if (tempy == 0) {
tempy = 1;
sy = 1;
} // end of if
if (sx == 0) {
x = tempx + tempx/Math.abs(tempx);
} // end of if
else {
x = tempx;
} // end of if-else
if (sy == 0) {
y = tempy + tempy/Math.abs(tempy);
} // end of if
else {
y = tempy;
} // end of if-else
int absx = Math.abs(x);
int absy = Math.abs(y);
int nex = x/absx;
int ney = y/absy;
int off = 0;
float count = 0;
float step = 0;
if (absx != absy) {
if (absx == Math.min(absx,absy)) {
step = (float) absx/absy;
calc1: for (int a=0; a<absy; a++) {
count += step;
if (count > 1 && x1+off != x2) {
count -= 1;
off += nex;
} // end of if
if (grid[x1+off][y1+a*ney] == 9) {
collide = false;
break calc1;
} // end of if
} // end of for
} // end of if
else{
step = (float) absy/absx;
calc2: for (int a=0; a<absx; a++) {
count += step;
if (count > 1 && y1+off != y2) {
count -= 1;
off += ney;
} // end of if
if (grid[x1+a*nex][y1+off] == 9) {
collide = false;
break calc2;
} // end of if
} // end of for
}
} // end of if
else {
calc3: for (int a=0; a<absx; a++) {
if (grid[x1+a*nex][y1+a*ney] == 9) {
collide = false;
break calc3;
} // end of if
} // end of for
} // end of if-else
return collide;
}
private int length(int x1, int y1, int x2, int y2) {
double distance = Math.sqrt(Math.pow(x1-x2,2)+Math.pow(y1-y2,2));
return (int) distance;
}
// Begin eventmethoden
public void paint (Graphics g){
boolean draw = true;
Color col;
for (int a=0; a<20; a++) {
for (int b=0; b<20; b++) {
draw = collide(a,b,light[0],light[1]);
if (draw) {
int len = Math.max(255-length(a*30+15,b*30+15,light[0]*30+15,light[1]*30+15),0);
col = new Color(len,len,len);
g.setColor(col);
g.fillRect(a*30,b*30,30,30);
} // end of if
else{
col = new Color(0,0,0);
g.setColor(col);
g.fillRect(a*30,b*30,30,30);
}
} // end of for
} // end of for
}
// Einde eventmethoden
} // end of class gridline
I'll understand it if nobody wants to look through a code as big as this, but it could be helpful for your own projects and I'm completely okay with it if you copy and paste my code for your projects.
Many thanks in advace.

Determine if circles intersect

I am working on a project where I have to draw 20 circles with random starting points and random sizes. Then I have to determine if any of the circles intersect. If a circle intersects with another, I have to color that circle green. And if the circle does not intersect with another, the color needs to be red. I have all of the code... I think... but when I run it, I still get some circles that should be green, but are red instead. Here is my code. Any help will be greatly appreciated.
import java.awt.Graphics;
import javax.swing.JPanel;
import java.util.Random;
import javax.swing.JFrame;
import java.awt.*;
public class IntersectingCircles extends JPanel
{
private int[] xAxis = new int [20]; // array to hold x axis points
private int[] yAxis = new int [20]; // array to hold y axis points
private int[] radius = new int [20]; // array to hold radius length
public static void main (String[] args)
{
JFrame frame = new JFrame("Random Circles");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new IntersectingCircles());
frame.pack();
frame.setVisible(true);
}
public IntersectingCircles()
{
setPreferredSize(new Dimension(1300, 800)); // set window size
Random random = new Random();
for (int i = 0; i < 20; i++)
{
xAxis[i] = random.nextInt(800) + 100;
yAxis[i] = random.nextInt(500) + 100;
radius[i] = random.nextInt(75) + 10;
}
}
public void paintComponent(Graphics g)
{
for (int i = 0; i < 20; i++)
{
int color = 0;
for (int h = 0; h < 20; h++)
{
if(i < h)
{
double x1 = 0, x2 = 0, y1 = 0, y2 = 0, d = 0;
x1 = (xAxis[i] + radius[i]);
y1 = (yAxis[i] + radius[i]);
x2 = (xAxis[h] + radius[h]);
y2 = (yAxis[h] + radius[h]);
d = (Math.sqrt(((x2 - x1) * (x2 - x1)) + ((y2 - y1)*(y2 - y1))));
if (d > radius[i] + radius[h] || d < (Math.abs(radius[i] - radius[h])))
{
color = 0;
}
else
{
color = 1;
break;
}
}
}
if (color == 0)
{
g.setColor(Color.RED);
g.drawOval(xAxis[i], yAxis[i], radius[i] * 2, radius[i] * 2);
}
else
{
g.setColor(Color.GREEN);
g.drawOval(xAxis[i], yAxis[i], radius[i] * 2, radius[i] * 2);
}
}
}
}

In the inside for loop, you are only comparing circles of i index with circles with h index, but only those with i < h, because of the condition:
for (int h = 0; h < 20; h++)
{
if(i < h)
{
...
So, instead you should compare every i circle with every h circle, except if they are the same. You want instead:
for (int h = 0; h < 20; h++)
{
if(i != h) //note the change here
{
...

Asteroid game NullPointerException error

I am having some serious problems with my Asteroid game. I'm trying to call my Game.java run() method in my main method in Asteroid.java but I keep getting the same error:
Exception in thread "main" java.lang.NullPointerException
at asteroids.Asteroids.main(Asteroids.java:15)
Java Result: 1
Can someone help me figure out why this is happening?
here is my code:
Asteroids.java
package asteroids;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.io.IOException;
#SuppressWarnings("serial")
public class Asteroids {
Game game = null;
public static void main(String[] args){
new Asteroids ().game.run ();
}
}
//NEW Game.java//
package asteroids;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Point2D;
import java.util.ArrayList;
//#SuppressWarnings("serial")
public class Game extends Applet implements Runnable, KeyListener {
//timing variables
Thread thread;
long startTime, endTime, framePeriod;
//graphics variables
Image img;
Dimension dim;
int width, height;
Graphics g;
//text items
int level, lives, score;
SpaceShip ship;
boolean shipCollision, shipExplode;
//ArrayList to hold asteroids
ArrayList<Asteroid> asteroids = new ArrayList<>();
int numOfAsteroids = 1;
//ArrayList to hold the lasers
ArrayList<Laser> lasers = new ArrayList<>();
final double rateOfFire = 10; //limits rate of fire
double rateOfFireRemaining; //decrements rate of fire
//ArrayList to hold explosion particles
ArrayList<AsteroidExplosion> explodingLines = new ArrayList<>();
//ArrayList to hold ship explosions
ArrayList<ShipExplosion> shipExplosion = new ArrayList<>();
public void Game ()
{
init();
}
public void init() {
resize(900,700); //set size of the applet
dim = getSize(); //get dimension of the applet
width = dim.width;
height = dim.height;
framePeriod = 25; //set refresh rate
addKeyListener(this); //to get commands from keyboard
setFocusable(true);
ship = new SpaceShip(width/2, height/2, 0, .15, .5, .15, .98); //add ship to game
shipCollision = false;
shipExplode = false;
level = numOfAsteroids;
lives = 3;
addAsteroids();
img = createImage(width, height); //create an off-screen image for double-buffering
g = img.getGraphics(); //assign the off-screen image
thread = new Thread(this);
thread.start();
}
#Override
public void paint(Graphics gfx) {
Graphics2D g2d = (Graphics2D) g;
//give the graphics smooth edges
RenderingHints rh = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
rh.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHints(rh);
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, width, height); //add a black background
//add text for lives, score, and level
g2d.setColor(Color.WHITE);
g2d.drawString("Level : " + level, 10, 690);
g2d.drawString("Lives : " + lives, 110, 690);
g2d.drawString("Score : " + score, 210, 690);
for(Asteroid a: asteroids) { //draw asteroids
a.draw(g2d);
}
for(Laser l : lasers) { //draw lasers
l.draw(g2d);
}
for(AsteroidExplosion e : explodingLines) {
e.draw(g2d);
}
for(ShipExplosion ex : shipExplosion)
ex.draw(g2d);
ship.draw(g2d); //draw ship
if(shipCollision) {
shipExplosion.add(new ShipExplosion(ship.getX(), ship.getY(), 10, 10));
ship.setX(width/2);
ship.setY(height/2);
shipCollision = false;
lives--;
}
gfx.drawImage(img, 0, 0, this); //draw the off-screen image (double-buffering) onto the applet
}
#Override
public void update(Graphics gfx) {
paint(gfx); //gets rid of white flickering
}
#Override
public void run(){
for( ; ; ) {
startTime = System.currentTimeMillis(); //timestamp
ship.move(width, height); //ship movement
for(Asteroid a : asteroids) { //asteroid movement
a.move(width, height);
}
for(Laser l : lasers) { //laser movement
l.move(width, height);
}
for(int i = 0 ; i<lasers.size() ; i++) { //laser removal
if(!lasers.get(i).getActive())
lasers.remove(i);
}
for(AsteroidExplosion e : explodingLines) { //asteroid explosion floating lines movement
e.move();
}
for(int i = 0 ; i<explodingLines.size(); i++) { //asteroid explosion floating lines removal
if(explodingLines.get(i).getLifeLeft() <= 0)
explodingLines.remove(i);
}
for(ShipExplosion ex : shipExplosion){ //ship explosion expansion
ex.expand();
}
for(int i = 0 ; i<shipExplosion.size() ; i++) {
if(shipExplosion.get(i).getLifeLeft() <= 0)
shipExplosion.remove(i);
}
rateOfFireRemaining--;
collisionCheck();
if(asteroids.isEmpty()) {
numOfAsteroids++;
addAsteroids();
level = numOfAsteroids;
}
repaint();
try {
endTime = System.currentTimeMillis(); //new timestamp
if(framePeriod - (endTime-startTime) > 0) //if there is time left over after repaint, then sleep
Thread.sleep(framePeriod - (endTime - startTime)); //for whatever is remaining in framePeriod
} catch(InterruptedException e) {}
}
}
#Override
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
//fires laser
if(key == KeyEvent.VK_SPACE) {
if(rateOfFireRemaining <= 0 ) {
lasers.add(ship.fire());
rateOfFireRemaining = rateOfFire;
}
}
if(key == KeyEvent.VK_UP)
ship.setAccelerating(true);
if(key == KeyEvent.VK_RIGHT)
ship.setTurningRight(true);
if(key == KeyEvent.VK_LEFT)
ship.setTurningLeft(true);
if(key == KeyEvent.VK_DOWN)
ship.setDecelerating(true);
}
#Override
public void keyReleased(KeyEvent e) {
int key = e.getKeyCode();
if(key == KeyEvent.VK_UP)
ship.setAccelerating(false);
if(key == KeyEvent.VK_RIGHT)
ship.setTurningRight(false);
if(key == KeyEvent.VK_LEFT)
ship.setTurningLeft(false);
if(key == KeyEvent.VK_DOWN)
ship.setDecelerating(false);
}
#Override
public void keyTyped(KeyEvent e) {
}
public void addAsteroids() {
int numAsteroidsLeft = numOfAsteroids;
int size;
for(int i=0 ; i<numOfAsteroids ; i++) { //add asteroids to game
//randomize starting position
int asteroidX = (int)(Math.random() * width) + 1;
int asteroidY = (int)(Math.random() * height) + 1;
//randomize speed and direction
double xVelocity = Math.random() + 1; //horizontal velocity
double yVelocity = Math.random() + 1; //vertical velocity
//used starting direction
int xDirection = (int)(Math.random() * 2);
int yDirection = (int)(Math.random() * 2);
//randomize horizontal direction
if (xDirection == 1)
xVelocity *= (-1);
//randomize vertical direction
if (yDirection == 1)
yVelocity *= (-1);
//if there are more then four asteroids, any new ones are MEGA asteroids
if(numAsteroidsLeft > 4) {
size = 2;
} else { size = 1;
}
asteroids.add(new Asteroid(size, asteroidX, asteroidY, 0, .1, xVelocity, yVelocity));
numAsteroidsLeft--;
//Make sure that no asteroids can appear right on top of the ship
//get center of recently created asteroid and ship and check the distance between them
Point2D asteroidCenter = asteroids.get(i).getCenter();
Point2D shipCenter = ship.getCenter();
double distanceBetween = asteroidCenter.distance(shipCenter);
//if asteroid center is within 80 pixels of ship's center, remove it from the ArrayList and rebuild it
if(distanceBetween <= 80) {
asteroids.remove(i);
i--;
numAsteroidsLeft++;
}
}
}
public void collisionCheck() {
//cycle through active asteroids checking for collisions
for(int i = 0 ; i < asteroids.size() ; i++) {
Asteroid a = asteroids.get(i);
Point2D aCenter = a.getCenter();
//check for collisions between lasers and asteroids
for(int j = 0 ; j < lasers.size() ; j++) {
Laser l = lasers.get(j);
Point2D lCenter = l.getCenter();
double distanceBetween = aCenter.distance(lCenter);
if(distanceBetween <= (a.getRadius() + l.getRadius())) {
//split larger asteroids into smaller ones, remove smaller asteroids from screen
if(a.getRadius() >= 60) {
for(int k = 0 ; k < 3 ; k++)
explodingLines.add(a.explode());
split(i);
score += 200;
} else if(a.getRadius() >= 30){
for(int k = 0 ; k < 3 ; k++)
explodingLines.add(a.explode());
split(i);
score += 100;
} else {
for(int k = 0 ; k < 3 ; k++)
explodingLines.add(a.explode());
asteroids.remove(i);
score += 50;
}
lasers.remove(j); //remove laser from screen
}
}
//check for collisions between ship and asteroid
Point2D sCenter = ship.getCenter();
double distanceBetween = aCenter.distance(sCenter);
if(distanceBetween <= (a.getRadius() + ship.getRadius())) {
shipCollision = true;
shipExplode = true;
}
}
}
public void split(int i) {
Asteroid a = asteroids.get(i);
double bigAsteroidX = a.getX();
double bigAsteroidY = a.getY();
int size = (a.getSize() / 2);
asteroids.remove(i);
for(int j = 0 ; j<2 ; j++) {
//randomize speed and direction
double xVelocity = Math.random() + 1; //horizontal velocity
double yVelocity = Math.random() + 1; //vertical velocity
//used randomize starting direction
int xDirection = (int)(Math.random() * 2);
int yDirection = (int)(Math.random() * 2);
//randomize horizontal direction
if (xDirection == 1)
xVelocity *= (-1);
//randomize vertical direction
if (yDirection == 1)
yVelocity *= (-1);
asteroids.add(new Asteroid(size, bigAsteroidX, bigAsteroidY, 0, .1, xVelocity, yVelocity));
}
}
}
//Edit Update//
Okay I tried a lot of stuff and discovered that even though the game works when I debug Game.java and it doesn't work when I run it through Asteroids.java. I found that img = createIimg = createImage(width, height); and g = img.getGraphics(); are returning null and that GraphicsEnvironment.isHeadless() is returning true. How should I change my to fix this issue?
Error
Exception in thread "main" java.lang.NullPointerException
at asteroids.Game.init(Game.java:67)
at asteroids.Game.Game(Game.java:45)
at asteroids.Asteroids.main(Asteroids.java:15)
Java Result: 1

You have the var "game" null, and you tried to call the method "run" on this var (game.run); obviously if "game" is null, you can't get the method, and throws nullpointer exception.
Game game=new Game();
that's all you need. Your final code is:
Game game = new Game();//<----- here is the change
public static void main(String[] args){
new Asteroids ().game.run ();
}

This thing is null.
new Asteroids ().game
That's why you get this NullPointerException when you call run on it.

Game game = null;
public static void main(String[] args){
new Asteroids ().game.run ();
}
The prgram is running from the main method. game is null.
Maybe you should have
Game game = new Game(); // instead of null

Try it may be help
Game game = null;
public static void main(String[] args){
If( Asteroids ().game != null ){
new Asteroids ().game.run ();
}
}

Program doesn't work - NullPointerException

I am using eclipse to export my project as a runnable jar file, when I try to run it nothing happens, when I run it using cmd I get this error.
C:\Users\Enes\Desktop>cmd.exe
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\Enes\Desktop>java -jar Game.Jar
Exception in thread "main" java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoa
der.java:58)
Caused by: java.lang.NullPointerException
at scrolls.Resources.createArray(Resources.java:111)
at scrolls.Player.<init>(Player.java:31)
at scrolls.Draw.<init>(Draw.java:27)
at scrolls.Frame.main(Frame.java:18)
... 5 more
C:\Users\Enes\Desktop>
When I run it using eclipse it runs fine with no errors or warnings.
This is my Resource file which seems to be causing the problem at line 111
package scrolls;
import java.awt.Font;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import javax.imageio.ImageIO;
import org.imgscalr.Scalr;
public class Resources
{
Map map;
static BufferedImage[] textures = new BufferedImage[8];
static BufferedImage[] mapTextures = new BufferedImage[9];
static BufferedImage texture;
static BufferedImage[] waterAnimated = new BufferedImage[64];
static BufferedImage water;
static BufferedImage icon;
public static Font f, fs;
static int imageCounter = 0;
public Resources()
{
map = new Map();
textures();
createArray(texture, textures, 32, 1, 8);
createArray(water, waterAnimated, 32, 64, 1);
getFont();
buildMapTextures(textures, mapTextures);
}
public static void counter()
{
imageCounter++;
if (imageCounter >= 500)
imageCounter = 0;
//System.out.println(imageCounter / 8);
}
private void buildMapTextures(BufferedImage[] textures, BufferedImage[] mapTextures)
{
for (int i = 0; i <= 7; i++)
{
mapTextures[i] = resize(textures[i], 3, 3);
}
mapTextures[8] = resize(waterAnimated[2], 3, 3);
}
private BufferedImage resize(BufferedImage image, int newW, int newH)
{
BufferedImage thumbnail = Scalr.resize(image, Scalr.Method.ULTRA_QUALITY, Scalr.Mode.FIT_EXACT, newW, newH, Scalr.OP_ANTIALIAS);
return thumbnail;
}
public static BufferedImage waterAnimation()
{
return waterAnimated[imageCounter / 8];
}
private void textures()
{
try
{
texture = ImageIO.read(new File("src/resources/textures.png"));
} catch (IOException e)
{
}
try
{
water = ImageIO.read(new File("src/resources/water.png"));
} catch (IOException e)
{
}
try
{
icon = ImageIO.read(new File("src/resources/icon.png"));
} catch (IOException e)
{
}
}
static BufferedImage player()
{
BufferedImage player = null;
try
{
player = ImageIO.read(new File("src/resources/player.png"));
} catch (IOException e)
{
}
return player;
}
static void createArray(BufferedImage image, BufferedImage[] images, int size, int rows, int cols)
{
BufferedImage temp = image;
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
{
images[(i * cols) + j] = temp.getSubimage(j * size, i * size, size, size); // line 111
}
}
}
public static void readLevel(String filename, int[][] level, int part)
{
try
{
File f = new File("src/resources/levels/" + part + "/" + filename + ".txt");
FileReader fr = new FileReader(f);
BufferedReader in = new BufferedReader(fr);
StringBuilder sb = new StringBuilder();
byte b = 0;
while ((b = (byte) in.read()) != -1)
{
sb.append("" + ((char) b));
}
String str = sb.toString();
String[] lines = str.split("(\n|\r)+");
for (int i = 0; i < lines.length; i++)
{
for (int j = 0; j < lines[i].length(); j++)
{
level[i][j] = Integer.parseInt("" + lines[i].charAt(j));
}
}
in.close();
} catch (Exception e)
{
e.printStackTrace();
}
}
private static void getFont()
{
try
{
f = Font.createFont(Font.TRUETYPE_FONT, new FileInputStream("src/resources/Jet Set.ttf"));
fs = Font.createFont(Font.TRUETYPE_FONT, new FileInputStream("src/resources/Jet Set.ttf"));
} catch (Exception e)
{
System.out.println(e);
}
f = f.deriveFont(22f);
fs = fs.deriveFont(13f);
}
}
Player code
package scrolls;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Transparency;
import java.awt.event.KeyEvent;
import java.awt.image.BufferedImage;
public class Player
{
static int x, y, dx, dy;
BufferedImage[] sprites = new BufferedImage[8];
int rotation = 0;
int imageCounter = 0;
public static boolean moving = false;
static int playerEnergy = 150000;
static int playerLvl = 1;
static int playerExp = 3;
static int expNeeded = (((playerLvl + 1) * playerLvl) * 2);
static int playerHealth = 100;
static int playerMana = 100;
static int mapRow = 6;
static int mapColumn = 8;
static int playerRow, playerColumn;
public Player()
{
y = 40;
x = 700;
Resources.createArray(Resources.player(), sprites, 66, 1, 8);
}
private void changeImage()
{
imageCounter++;
if (imageCounter >= 80)
imageCounter = 0;
}
public void move()
{
y = y + dy;
x = x + dx;
changeImage();
playerPosition();
}
static void mapPosition()
{
if (y < 0)
playerRow = 0;
else
playerRow = (y / 32) + 1;
if (x < 0)
playerColumn = 0;
else
playerColumn = (x / 32) + 1;
}
private void playerPosition()
{
if (x >= 817 - 59)
{
x = -24;
mapColumn++;
}
if (x <= -25)
{
x = 817 - 59;
mapColumn--;
}
if (y <= -25)
{
y = 599 - 152 - 41;
mapRow--;
}
if (y >= 599 - 152 - 40)
{
y = -24;
mapRow++;
}
}
public static int playerExp()
{
return playerExp;
}
public static int getNextExp()
{
return expNeeded;
}
public static int playerLvl()
{
if (playerExp >= expNeeded)
{
playerLvl++;
}
return playerLvl;
}
public static int playerHealth()
{
return playerHealth;
}
public static int playerMana()
{
return playerMana;
}
public static int playerEnergy()
{
if ((dx != 0) || (dy != 0))
playerEnergy--;
if ((dx != 0) && (dy != 0))
playerEnergy--;
return playerEnergy;
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public static BufferedImage rotate(BufferedImage image, double angle)
{
double sin = Math.abs(Math.sin(angle)), cos = Math.abs(Math.cos(angle));
int w = image.getWidth(), h = image.getHeight();
int neww = (int) Math.floor(w * cos + h * sin), newh = (int) Math.floor(h * cos + w * sin);
GraphicsConfiguration gc = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration();
BufferedImage result = gc.createCompatibleImage(neww, newh, Transparency.TRANSLUCENT);
Graphics2D g = result.createGraphics();
g.translate((neww - w) / 2, (newh - h) / 2);
g.rotate(angle, w / 2, h / 2);
g.drawRenderedImage(image, null);
g.dispose();
return result;
}
public BufferedImage getPlayerImage()
{
roatePlayer();
int image = animatePlayer();
double angle = Math.toRadians(rotation);
if (dy != 0 || dx != 0)
{
return rotate(sprites[image], angle);
}
return rotate(sprites[0], angle);
}
private int animatePlayer()
{
return imageCounter / 10;
}
private void roatePlayer()
{
if (dy > 0)
rotation = 0;
if (dy < 0)
rotation = 180;
if (dx > 0)
rotation = -90;
if (dx < 0)
rotation = 90;
if (dy > 0 && dx > 0)
rotation = -45;
if (dy > 0 && dx < 0)
rotation = 45;
if (dy < 0 && dx < 0)
rotation = 135;
if (dy < 0 && dx > 0)
rotation = -135;
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if (key == KeyEvent.VK_A)
{
dx = -1;
rotation = -90;
}
if (key == KeyEvent.VK_S)
{
dy = 1;
rotation = 0;
}
if (key == KeyEvent.VK_D)
{
dx = 1;
rotation = 90;
}
if (key == KeyEvent.VK_W)
{
dy = -1;
rotation = 180;
}
}
public void keyReleased(KeyEvent e)
{
int key = e.getKeyCode();
if (key == KeyEvent.VK_A)
dx = 0;
if (key == KeyEvent.VK_S)
dy = 0;
if (key == KeyEvent.VK_D)
dx = 0;
if (key == KeyEvent.VK_W)
dy = 0;
}
}

I strongly suspect that you're loading some resources (sounds, images) either by assuming that they're present as files, or you're using appropriate getResource / getResourceAsStream calls, but your resources aren't present in the jar file. We can't really tell without seeing any of your code or what's in your jar file, but you should check where you're loading the resource, and why you expect the resource to be found.
Oh, and you may have a casing issue too - when it's loading resources from the Windows file system, asking for FOO.PNG will work even if the file is called foo.png; the same is not true when loading resources from a jar file.
Of course, you should look at Resources.java line 111 and Player.java line 31 to help pin down exactly what's going wrong (e.g. which resource is failing).
EDIT: Okay, now that we've got the code, it's exactly as I first suggested. This line of code in Resource.player():
player = ImageIO.read(new File("src/resources/player.png"));
... is loading player.png expecting it to be a file on the local file system. You want something like:
player = ImageIO.read(Resource.class.getResource("/src/resources/player.png"));
It's odd to have a src folder in your jar file, by the way. If you've actually just got the image in a reources directory, you'd want:
player = ImageIO.read(Resource.class.getResource("/resources/player.png"));

Java (swing) paint only what's viewable on the screen

I am making a tile based platformer game in java. I render a map which is stored in a 2 dimensional array but when this array is very big my game starts to become slow. I realised that I had to only render the part of the map that is viewable, I tried to do that but i wrote very hacky code that only worked partly so I removed it. How can I do this properly? Here is my code (without the hacky stuff). Also how could I use System.nanoTime() rather than System.currentTimeMillis()?
package sexy_robot_from_another_dimension;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.TexturePaint;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class Game extends JPanel
{
int playerX = 50;
int playerY = 50;
static boolean up = false;
static boolean down = false;
static boolean right = false;
static boolean left = false;
int playerSpeed = 1;
String[][] map;
int blockSize = 20;
int jumpLoop = 0;
int maxJumpLoop = 280;
static BufferedImage block, player;
int playerWidth = 20;
int playerHeight = 35;
int cameraX = 0;
int cameraY = 0;
long nextSecond = System.currentTimeMillis() + 1000;
int frameInLastSecond = 0;
int framesInCurrentSecond = 0;
public Game()
{
super();
try
{
map = load("/maps/map1.txt");
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
Timer timer = new Timer();
TimerTask task = new TimerTask()
{
#Override
public void run()
{
if(up)
{
if((!playerIsOnBlock(playerX, playerY).equals("0")) || (!playerIsOnBlock(playerX + (playerWidth - 1), playerY).equals("0")))
{
timeToJump();
}
}
if(down)
{
}
if(right)
{
if((playerIsLeftBlock(playerX, playerY).equals("0")) && (playerIsLeftBlock(playerX, playerY + (playerHeight/2 - 1)).equals("0")) && (playerIsLeftBlock(playerX, playerY + (playerHeight - 1)).equals("0")))
{
playerX += playerSpeed;
}
}
if(left)
{
if((playerIsRightBlock(playerX, playerY).equals("0")) && (playerIsRightBlock(playerX, playerY + (playerHeight/2 - 1)).equals("0")) && (playerIsRightBlock(playerX, playerY + (playerHeight - 1)).equals("0")))
{
playerX -= playerSpeed;
}
}
repaint();
}
};
timer.scheduleAtFixedRate(task, 0, 10);
Timer timerGrav = new Timer();
TimerTask taskGrav = new TimerTask()
{
#Override
public void run()
{
if((playerIsOnBlock(playerX, playerY).equals("0")) && (playerIsOnBlock(playerX + (playerWidth - 1), playerY).equals("0")))
{
playerY += playerSpeed;
repaint();
}
}
};
timerGrav.scheduleAtFixedRate(taskGrav, 0, 6);
}
void timeToJump()
{
if(jumpLoop == 0)
{
jumpLoop = 1;
Timer timer = new Timer();
TimerTask task = new TimerTask()
{
#Override
public void run()
{
if((playerIsBelowBlock(playerX, playerY).equals("0")) && (playerIsBelowBlock(playerX + (playerWidth - 1), playerY).equals("0")))
{
playerY -= playerSpeed;
jumpLoop++;
repaint();
}
else
{
jumpLoop = maxJumpLoop;
}
if(jumpLoop == maxJumpLoop)
{
jumpLoop = 0;
cancel();
}
}
};
timer.scheduleAtFixedRate(task, 0, 3);
}
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
long currentTime = System.currentTimeMillis();
if (currentTime > nextSecond)
{
nextSecond += 1000;
frameInLastSecond = framesInCurrentSecond;
framesInCurrentSecond = 0;
}
framesInCurrentSecond++;
g.drawString(frameInLastSecond + " fps", 10, 20);
cameraX = -playerX + getWidth()/2;
cameraY = -playerY + getHeight()/2;
g.translate(cameraX, cameraY);
for (int x = 0; x < map.length; x++)
{
for (int y = 0; y < map[0].length; y++)
{
switch(map[x][y])
{
case "0":
break;
case "1":
if(block != null)
{
TexturePaint tp0 = new TexturePaint(block, new Rectangle(0, 0, blockSize, blockSize));
g2.setPaint(tp0);
}
g.fillRect(y*blockSize, x*blockSize, 20, 20);
break;
}
}
}
g.setColor(Color.BLACK);
if(player != null)
{
TexturePaint tp0 = new TexturePaint(player, new Rectangle(playerX, playerY, playerWidth, playerHeight));
g2.setPaint(tp0);
}
g.fillRect(playerX, playerY, playerWidth, playerHeight);
g.setColor(Color.black);
g.setFont(new Font("Droid Sans Mono", Font.PLAIN, 12));
g.drawString("Sexy!", playerX - 5, playerY - 10);
}
boolean outOfMap(int x, int y)
{
y -= blockSize - 1;
x -= blockSize - 1;
if((y/blockSize <= map.length - 2) && (y/blockSize >= 0) && (x/blockSize <= map[0].length-2) && (x/blockSize >= 0))
{
return false;
}
return true;
}
String playerIsOnBlock(int x, int y)
{
y += playerHeight;
if(!outOfMap(x, y))
{
if(map[y/blockSize][x/blockSize] != "0")
{
return map[y/blockSize][x/blockSize];
}
}
return "0";
}
String playerIsBelowBlock(int x, int y)
{
y -= playerSpeed;
if(!outOfMap(x, y))
{
if(map[y/blockSize][x/blockSize] != "0")
{
return map[y/blockSize][x/blockSize];
}
}
return "0";
}
String playerIsLeftBlock(int x, int y)
{
x += playerWidth;
if(!outOfMap(x, y))
{
if(map[y/blockSize][x/blockSize] != "0")
{
return map[y/blockSize][x/blockSize];
}
}
return "0";
}
String playerIsRightBlock(int x, int y)
{
x -= playerSpeed;
if(!outOfMap(x, y))
{
if(map[y/blockSize][x/blockSize] != "0")
{
return map[y/blockSize][x/blockSize];
}
}
return "0";
}
String[][] load(String file) throws IOException
{
BufferedReader br = new BufferedReader(new InputStreamReader(getClass().getResourceAsStream(file)));
int lines = 1;
int length = br.readLine().split(" ").length;
while (br.readLine() != null) lines++;
br.close();
br = new BufferedReader(new InputStreamReader(getClass().getResourceAsStream(file)));
String[][] map = new String[lines][length];
for (int i = 0; i < lines; i++)
{
String line = br.readLine();
String[] parts = line.split(" ");
for (int y = 0; y < length; y++)
{
map[i][y] = parts[y];
}
}
br.close();
return map;
}
}
Thank you!

It seems your camera is centered on the player, then there are two ways of doing this, I like the first way, it is a bit cleaner:
1th: Create a rectangle that bounds your cameras view, and check if the map x,y is within this view, render only if true.
Rectangle cameraView = new Rectangle(playerX - getWidth() / 2, playerY - getHeight() / 2, getWidth(), getHeight());
for (int x = 0; x < map.length; x++) {
for (int y = 0; y < map[0].length; y++) {
if (!cameraView.contains(x*blockSize, y*blockSize))
continue;
switch (map[x][y]) {
case "0":
break;
case "1":
if (block != null) {
TexturePaint tp0 = new TexturePaint(block, new Rectangle(0, 0, blockSize, blockSize));
g2.setPaint(tp0);
}
g.fillRect(y * blockSize, x * blockSize, 20, 20);
break;
}
}
}
The second option is to simply calculate the distance to the center of the screen (playerX,playerY) from each map[x][y] and skip all map[x][y] that falls outside your viewing bounds, this is a bit uglier to code and I really don't recommend this, the rectangle option above should be fast enough.
Edit:
#JasonC That is true, I didn't consider for instance when an x value is definitely outside the view, it will still go into the y loop through all the y values. One can simply create a dummy variable in the x-loop and do the following check
for (int x = 0; x < map.length; x++) {
int dummyY = playerY
if(!cameraView.contains(x,dummyY))
continue;
....
//rest of code ommitted
Another optimization you can do is considering not setting a TexturePaint (expensive operation) but instead simply drawing the image of the block:
g.fillRect(y * blockSize, x * blockSize, 20, 20);
Replaced with
g.drawImage(block, y*blockSize, x*blockSize, null);
The same with the playerimage.

Set the clipping region to the visible area with Graphics.setClip(), that will prevent most rendering operations from taking effect outside that region.
For drawing operations where this isn't sufficient (perhaps you also want to avoid doing calculations or something for objects outside the clipping area), test your objects bounds against the clipping rectangle and skip the object if it doesn't intersect.
See Graphics.setClip().
A further optimization can be done by, for example, calculating the range of blocks on your map that is definitely outside of the visible area, and excluding that from your for loop (no sense testing blocks against the clipping region if you know they are outside already). Take the clipping region, transform it to map index coordinates, then you will know where in your map the visible area is and you can just iterate over that subsection of the map.