Develop Reference

Error in setting my character in the right color pixel in java

I am having some issues trying to set my character to spawn in the right color spot in my map sheet in java.
In the vídeos that I am watching to learn this I have every single line code identical to the vídeo but yet my character instead of spawning in the right spot is spawning in the up middle corner of the screen.
I'm using those code lines to make him and all Tiles and Entities spawn in the right spot :
public class World {
private Tile[] tiles;
public static int WIDTH,HEIGHT;
public World(String path) {
try {
BufferedImage map = ImageIO.read(getClass().getResource(path));
int[] pixels = new int[map.getWidth() * map.getHeight()];
WIDTH = map.getWidth();
HEIGHT = map.getHeight();
tiles = new Tile[map.getWidth() * map.getHeight()];
map.getRGB(0, 0, map.getWidth(), map.getHeight(), pixels, 0, map.getWidth());
for(int xx = 0; xx < map.getWidth(); xx++) {
for(int yy = 0; yy < map.getHeight(); yy++) {
int pixelAtual = pixels[xx + (yy*map.getWidth())];
tiles[xx + (yy * WIDTH)] = new FloorTile(xx*16,yy*16, Tile.TILE_FLOOR);
if(pixelAtual == 0xFF000000) {
//FLOOR
tiles[xx + (yy * WIDTH)] = new FloorTile(xx*16,yy*16, Tile.TILE_FLOOR);
}else if(pixelAtual == 0xFFFFFFFF){
//PAREDE
tiles[xx + (yy * WIDTH)] = new FloorTile(xx*16,yy*16, Tile.TILE_WALL);
}else if(pixelAtual == 0xFF0026FF) {
//Player
Game.player.setX(xx*16);
Game.player.setY(yy*16);
}else if(pixelAtual == 0xFFFF0000){
//Enemy
}else if(pixelAtual == 0xFFFF00DC) {
//WEAPON
}else if(pixelAtual == 0xFFFF7F7F) {
//LIFEPACK
}else if(pixelAtual == 0xFFFFD800) {
//BULLET
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
public void render(Graphics g) {
for(int xx = 0; xx < WIDTH; xx++) {
for(int yy = 0; yy < HEIGHT; yy++) {
Tile tile = tiles[xx + (yy*WIDTH)];
tile.render(g);
}
}
}
}
But when I use these two code lines that are from my Entity Class that are suposed to make my character spawn in the right place it doesn't work at all!
Game.player.setX(xx16);
Game.player.setY(yy16);
Here's my Entity Class for you to see if i did something wrong, and again, i did everything exactely like int the vídeo an in the vídeo it worked.
public class Entity {
public static BufferedImage LIFEPACK_EN = Game.spritesheet.getSprite(78, 0, 16, 16);
public static BufferedImage WEAPON_EN = Game.spritesheet.getSprite(96, 0, 16, 16);
public static BufferedImage BULLET_EN = Game.spritesheet.getSprite(78, 16, 16, 16);
public static BufferedImage ENEMY_EN = Game.spritesheet.getSprite(96, 16, 16, 16);
protected double x;
protected double y;
protected int width;
protected int height;
private BufferedImage sprite;
public Entity(int x, int y, int width, int height, BufferedImage sprite) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
this.sprite = sprite;
}
public void setX(int newX) {
this.x = newX;
}
public void setY(int newY) {
this.x = newY;
}
public int getX() {
return (int)this.x;
}
public int getY() {
return (int)this.y;
}
public int getWidth() {
return this.width;
}
public int getHeight() {
return this.height;
}
public void update() {
}
public void render(Graphics g) {
g.drawImage(sprite, this.getX(), this.getY(), null);
}
}

I saw where I was wrong.
public void setY(int newY) {
this.x = newY;
In this line code here, it's suposed to be this.y and I thought that I did that, but I couldn't see.

Can't seem to access the image file in my PlayerClass even though it is properly loaded

I'm creating a 2D java game and ran into a nullpointer exception. Whenever I call my render in the playstate class, it throws the exception. I had previously rendered the Font file and got it to work when commenting out the player object references. The player "linkformatted.png" file is able to load after trying and catching, but the nullpointer exception stays. Changing the values didn't work.
public class PlayState extends GameState {
private Font font;
private Player player;
public PlayState(GameStateManager gsm) {
super(gsm);
font = new Font("font/ZeldaFont.png", 16, 16);
player = new Player(new Sprite("entity/linkformatted.png"), new Vector2f(100, 100), 32);
}
public void update() {
player.update();
}
public void input(MouseHandler mouse, KeyHandler key) {
player.input(mouse, key);
}
public void render(Graphics2D g) {
Sprite.drawArray(g, font, "YOU", new Vector2f(100, 100), 32, 32, 16, 0);
player.render(g);
}
}
public class Sprite {
private BufferedImage SPRITESHEET = null;
private BufferedImage[][] spriteArray;
private final int TILE_SIZE = 32;
public int w;
public int h;
private int wSprite;
private int hSprite;
public Sprite(String file) {
w = TILE_SIZE;
h = TILE_SIZE;
System.out.println("Loading: " + file + "...");
SPRITESHEET = loadSprite(file);
wSprite = SPRITESHEET.getWidth() / w;
hSprite = SPRITESHEET.getHeight() / h;
loadSpriteArray();
}
public Sprite(String file, int w, int h) {
this.w = w;
this.h = h;
System.out.println("Loading: " + file + "...");
SPRITESHEET = loadSprite(file);
wSprite = SPRITESHEET.getWidth() / w;
hSprite = SPRITESHEET.getHeight() / h;
loadSpriteArray();
}
public void setSize(int width, int height) {
setWidth(width);
setHeight(height);
}
public void setWidth(int i) {
w = i;
wSprite = SPRITESHEET.getWidth() / w;
}
public void setHeight(int i) {
h = i;
hSprite = SPRITESHEET.getHeight() / h;
}
public int getWidth() {
return w;
}
public int getHeight() {
return h;
}
private BufferedImage loadSprite(String file) {
BufferedImage sprite = null;
try {
sprite = ImageIO.read(getClass().getClassLoader().getResourceAsStream(file));
} catch(Exception e) {
System.out.println("Error: could not load file: " + file);
}
return sprite;
}
public void loadSpriteArray() {
spriteArray = new BufferedImage[wSprite][hSprite];
for(int x = 0; x < wSprite; x++) {
for(int y = 0; y < hSprite; y++) {
spriteArray[x][y] = getSprite(x, y);
}
}
}
public BufferedImage getSpriteSheet() {
return SPRITESHEET;
}
public BufferedImage getSprite(int x, int y) {
return SPRITESHEET.getSubimage(x * w, y * h, w, h);
}
public BufferedImage[] getSpriteArray(int i) {
return spriteArray[i];
}
public BufferedImage[][] getSpriteArray2(int i) {
return spriteArray;
}
public static void drawArray(Graphics2D g, ArrayList<BufferedImage> img, Vector2f pos, int width, int height, int xOffset, int yOffset) {
float x = pos.x;
float y = pos.y;
for(int i = 0; i < img.size(); i++) {
if(img.get(i) != null) {
g.drawImage(img.get(i), (int) x, (int) y, width, height, null);
}
x += xOffset;
y += yOffset;
}
}
public static void drawArray(Graphics2D g, Font f, String word, Vector2f pos, int width, int height, int xOffset, int yOffset) {
float x = pos.x;
float y = pos.y;
for(int i = 0; i < word.length(); i++ ) {
if(word.charAt(i) != 32); // the space
g.drawImage(f.getFont(word.charAt(i)), (int) x, (int) y, width, height, null);
x += xOffset;
y += yOffset;
}
}
}
public class Animation {
private BufferedImage[] frames;
private int currentFrame;
private int numFrames;
private int count;
private int delay;
private int timesPlayed;
public Animation(BufferedImage[] frames) {
timesPlayed = 0;
setFrames(frames);
}
public Animation() {
timesPlayed = 0;
}
public void setFrames(BufferedImage[] frames) {
frames = frames;
currentFrame = 0;
timesPlayed = 0;
delay = 2;
numFrames = frames.length;
}
public void setDelay(int i) { delay = i;}
public void setFrame(int i) { currentFrame = i;}
public void setNumFrames(int i) { numFrames = i;}
public void update() {
if(delay == -1) return;
count++;
if(count == delay) {
currentFrame++;
count = 0;
}
if(currentFrame == numFrames) {
currentFrame = 0;
timesPlayed++;
}
}
public int getDelay() {
return delay;
}
public int getFrame() {
return currentFrame;
}
public int getCount() {
return count;
}
public BufferedImage getImage() {
return frames[currentFrame];
}
public boolean hasPlayedOnce() {
return timesPlayed > 0;
}
public boolean hasPlayed(int i) {
return timesPlayed == i;
}
}
public class Player extends Entity {
public Player(Sprite sprite, Vector2f origin, int size) {
super(sprite, origin, size);
}
public void move() {
if(up) {
dy -= acc;
if(dy < -maxSpeed) {
dy = -maxSpeed;
}
} else {
if(dy < 0) {
dy += deacc;
if(dy > 0) {
dy = 0;
}
}
}
if(down) {
dy += acc;
if(dy < maxSpeed) {
dy = maxSpeed;
}
} else {
if(dy > 0) {
dy -= deacc;
if(dy < 0) {
dy = 0;
}
}
}
if(left) {
dx -= acc;
if(dx < -maxSpeed) {
dy = -maxSpeed;
}
} else {
if(dx < 0) {
dx += deacc;
if(dx > 0) {
dx = 0;
}
}
}
if(right) {
dx += acc;
if(dx > maxSpeed) {
dy = maxSpeed;
}
} else {
if(dx > 0) {
dx -= deacc;
if(dx < 0) {
dx = 0;
}
}
}
}
public void update() {
super.update();
move();
pos.x = dx;
pos.y = dy;
}
#Override
public void render(Graphics2D g) {
g.drawImage(ani.getImage(), (int) (pos.x), (int) (pos.y), size, size, null);
}
public void input(MouseHandler mouse, KeyHandler key) {
if(key.up.down) {
up = true;
} else {
up = false;
}
if(key.down.down) {
down = true;
} else {
down = false;
}
if(key.left.down) {
left = true;
} else {
left = false;
}
if(key.right.down) {
right = true;
} else {
right = false;
}
if(key.attack.down) {
attack = true;
} else {
attack = false;
}
}
}
Here is what is printed:
Loading: entity/linkformatted.png...
Exception in thread "GameThread" java.lang.NullPointerException
at com.zwellis.game.graphics.Animation.getImage(Animation.java:62)
at com.zwellis.game.entity.Player.render(Player.java:82)
at com.zwellis.game.states.PlayState.render(PlayState.java:34)
at com.zwellis.game.states.GameStateManager.render(GameStateManager.java:71)
at com.zwellis.game.GamePanel.render(GamePanel.java:133)
at com.zwellis.game.GamePanel.run(GamePanel.java:90)
at java.base/java.lang.Thread.run(Thread.java:834)
Here is what happens when I made another file to display the image:
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
public class ImageInFrame {
public static void main(String[] args) throws IOException {
String path = "entity/linkformatted.png";
File file = new File(path);
BufferedImage image = ImageIO.read(file);
JLabel label = new JLabel(new ImageIcon(image));
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(label);
f.pack();
f.setLocation(200,200);
f.setVisible(true);
}
}
Here is what happens:
Exception in thread "main" javax.imageio.IIOException: Can't read input file!
at java.desktop/javax.imageio.ImageIO.read(ImageIO.java:1308)
at ImageInFrame.main(ImageInFrame.java:11)
Here is also the github link
https://github.com/xfyktcl/ZwellisKnight.git

java Tile based game ArrayIndexOutOfBoundsException error

I have ArrayIndexOutOfBoundsException error in getTile function which is in the World class, my problem is that i cannot floor the background with background image, I cannot add other tiles i got empty window and these errors.
package com.game.Tiles;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
public class Tile {
// static stuff
public static Tile[] tiles = new Tile[512];
public static Tile background = new Background(0);
public static Tile target = new Target(1);
// class
public static final int TILE_WIDTH = 50, TILE_HEIGHT = 50;
protected BufferedImage texture;
protected final int id;
public Tile(BufferedImage texture, int id) {
super();
this.texture = texture;
this.id = id;
tiles[id] = this; // class ı tile a ekliyoruz yukardan gelen id ile
}
public void tick(){
}
public void render(Graphics graphic, int positionX, int positionY){
graphic.drawImage(texture, positionX, positionY, TILE_WIDTH, TILE_HEIGHT, null);
}
public int getId() {
return this.id;
}
public boolean isPasseble()
{
return false;
}
}
package com.game.world;
import java.awt.Graphics;
import com.game.Tiles.Tile;
public class World {
private int height, width;
private int[][] tiles;
public World(){
this.loadWorld();
}
public void tick(){
}
public void render(Graphics graphic){
for (int y = 0; y < this.height; y++) {
for(int x = 0; y < this.width; x++){
this.getTile(x, y).render(graphic, x * Tile.TILE_HEIGHT, y * Tile.TILE_WIDTH);
}
}
}
public Tile getTile(int x, int y){
Tile t = Tile.tiles[this.tiles[x][y]];
if(t == null)
return Tile.background;
return t;
}
private void loadWorld(){
this.width = 30;
this.height = 30;
this.tiles = new int[this.width][this.height];
for (int x = 0; x < this.width; x++) {
for (int y = 0; y < this.height; y++) {
this.tiles[x][y] = 0;
}
}
}
}
Errors:
Exception in thread "Thread-0"
java.lang.ArrayIndexOutOfBoundsException: 30
at com.game.world.World.getTile(World.java:28)
at com.game.world.World.render(World.java:23)
at com.game.States.GameState.render(GameState.java:29)
at com.game.Launcher.Game.render(Game.java:73)
at com.game.Launcher.Game.run(Game.java:98)
at java.lang.Thread.run(Thread.java:745)

This line should
for(int x = 0; y < this.width; x++){
should be
for(int x = 0; x < this.width; x++){

How come the collision detection only works sometimes?

I am creating an android app and I am creating a game and the droid has to be able to bounce off the walls and the edge of the screen. Here is my update method in my MainGamePanel.java file where I call the collision detection.
It works when it just has to bounce off the edge of the screen. However when I try to get it bounce off the wall objects it sometimes works. When it doesn't, it goes through the wall sometimes, although this only happens when it moves up and down. It also sometimes gets stuck in the wall. How would I modify the collision detection so I won't have these issues. Any help would be much appreciated.
public void update()
{
// check collision with right wall if heading right
if (droid.getSpeed().getxDirection() == Speed.DIRECTION_RIGHT
&& droid.getX() + droid.getBitmap().getWidth() / 2 >= getWidth()) {
droid.getSpeed().toggleXDirection();
}
// check collision with left wall if heading left
else if (droid.getSpeed().getxDirection() == Speed.DIRECTION_LEFT
&& droid.getX() - droid.getBitmap().getWidth() / 2 <= 0) {
droid.getSpeed().toggleXDirection();
droid.getSpeed().setYv(0);
}
// check collision with bottom wall if heading down
else if (droid.getSpeed().getyDirection() == Speed.DIRECTION_DOWN
&& droid.getY() + droid.getBitmap().getHeight() / 2 >= getHeight()) {
droid.getSpeed().toggleYDirection();
droid.getSpeed().setXv(0);
}
// check collision with top wall if heading up
else if (droid.getSpeed().getyDirection() == Speed.DIRECTION_UP
&& droid.getY() - droid.getBitmap().getHeight() / 2 <= 0) {
droid.getSpeed().toggleYDirection();
droid.getSpeed().setXv(0);
}
for (int i = 0 ; i < listOfWs.length ; i++)
{
if (droid.getX() +(droid.getBitmap().getWidth()/2)+1 > listOfWs [i].giveLeft ()
&& droid.getX()-(droid.getBitmap().getWidth()/2)-1 < listOfWs [i].giveRight ()
&& droid.getY()+(droid.getBitmap().getHeight()/2)+1 > listOfWs [i].giveTop ()
&& droid.getY()-(droid.getBitmap().getHeight()/2)-1 < listOfWs [i].giveBottom () )
{
if(droid.getSpeed().getYv()==0){
droid.getSpeed().toggleXDirection();//Takes the speed and multiplies it by -1 so it changes direction
}
else{
droid.getSpeed().toggleYDirection();
}
}
}
// Update the lone droid
droid.update();
}
Here is my droid.java file that I used.
public class Droid {
private Bitmap bitmap; // the actual bitmap
private int x; // the X coordinate
private int y; // the Y coordinate
public Speed speed;
public Droid(Bitmap bitmap, int x, int y) {
this.bitmap = bitmap;
this.x = x;
this.y = y;
speed= new Speed();
}
public Bitmap getBitmap() {
return bitmap;
}
public void setBitmap(Bitmap bitmap) {
this.bitmap = bitmap;
}
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 void draw(Canvas canvas) {
canvas.drawBitmap(bitmap, x - (bitmap.getWidth() /2), y - (bitmap.getHeight() / 2), null);
}
public void update() {
x += (int)(speed.getXv() * speed.getxDirection());
y += (int)(speed.getYv() * speed.getyDirection());
}
public Speed getSpeed(){
return speed;
}
}
This is the speed.java file.
public class Speed {
public static final int DIRECTION_RIGHT = 4;
public static final int DIRECTION_LEFT = -4;
public static final int DIRECTION_UP = -4;
public static final int DIRECTION_DOWN = 4;
private float xv = 1; // velocity value on the X axis
private float yv = 1; // velocity value on the Y axis
private int xDirection = DIRECTION_RIGHT;
private int yDirection = DIRECTION_DOWN;
public Speed() {
this.xv = 1;
this.yv = 1;
}
public Speed(float xv, float yv) {
this.xv = xv;
this.yv = yv;
}
public float getXv() {
return xv;
}
public void setXv(float xv) {
this.xv = xv;
}
public float getYv() {
return yv;
}
public void setYv(float yv) {
this.yv = yv;
}
public int getxDirection() {
return xDirection;
}
public void setxDirection(int xDirection) {
this.xDirection = xDirection;
}
public void setRight() {
xDirection = DIRECTION_RIGHT;
}
public void setLeft() {
xDirection = DIRECTION_LEFT;
}
public void setUp() {
yDirection = DIRECTION_UP;
}
public void setDown() {
yDirection = DIRECTION_DOWN;
}
public int getyDirection() {
return yDirection;
}
public void setyDirection(int yDirection) {
this.yDirection = yDirection;
}
// changes the direction on the X axis
public void toggleXDirection() {
xDirection = xDirection * -1;
}
// changes the direction on the Y axis
public void toggleYDirection() {
yDirection = yDirection * -1;
}
}

in the update method, in for circulation, it seems you make your logical operation there, would you make it more specific?

Java Object Array - Drop objects in array by int

Im currently am working on a game in Java that spawns blocks on the top of the screen and they fall down (you have to dodge them). Currently I have the game spawning blocks on the top of the screen from an array but I do not know how to make their y position go down by (int).
Basically I just need help making a public void that checks an object array and with every instance of a object it finds it drops the y position of it by 12.
Selected snippits from code:
static Object[][] food = new Object[7][700];
public void draw() {
try {
Graphics g = bufferStrategy.getDrawGraphics();
g.clearRect(0, 0, this.getSize().width, this.getSize().height);
// Draw to back buffer
g.setColor(Color.WHITE);
g.fillRect(0, 0, this.getSize().width, this.getSize().height);
g.setColor(Color.BLUE);
g.fillRect(Player.getX(), Player.getY(), Player.WIDTH, Player.HEIGHT);
g.setColor(Color.GRAY);
for(int x = 0; x < food.length; x++) {
for(int y = 0; y < food[x].length; y ++) {
Object o = food[x][y];
if(o instanceof Hamburger) {
new Hamburger(x * 100, y, g);
}
else if(o instanceof Salad) {
new Salad(x * 100, y, g);
}
}
}
GUI.draw(g);
} catch(Exception e) {
e.printStackTrace();
} finally {
bufferGraphics.dispose();
}
}
public void dropBlocks() {
}
public void addBlock() {
if(new Random().nextInt(2) == 1) {
food[new Random().nextInt(7)][0] = new Hamburger(0, 0);
} else food[new Random().nextInt(7)][0] = new Salad(0, 0);
}
public void drawBackbufferToScreen() {
bufferStrategy.show();
Toolkit.getDefaultToolkit().sync();
}
public void run() {
int i = 0;
while(running) {
i++;
draw();
Player.update();
drawBackbufferToScreen();
if(i == 50) {
addBlock();
i = 0;
}
dropBlocks();
Thread.currentThread();
try {
Thread.sleep(10);
} catch(Exception e) {
e.printStackTrace();
}
}
}
Food.java (What Hamburger and Salad extend)
public class Food {
public static int x;
public static int y;
public static int HEIGHT;
public static int WIDTH;
public int type;
private static Image blockImage;
// Default constructor
public Food() {
Food.x = 0;
Food.y = 0;
Food.HEIGHT = 80;
Food.WIDTH = 80;
}
public Food(int x, int y) {
Food.x = x;
Food.y = y;
Food.HEIGHT = 80;
Food.WIDTH = 80;
}
// Getters and setters

I would do something like this:
Object[][] board = new Object[7][700]; //Game board.
//you can also switch the width and height
//Initialization
for (int x = 699; x >= 0; x--) {
for (int y = 0; y < 7; y++) {
if (x == 699) {
board[y][x] = BLANK; //set spot to open if it is the bottom row
continue;
}
board[y][x+1] = board[y][x]; //move row down
}
}
//Generate new Objects if needed for the top row of the board.

Clearly Object does not have a getY() method. You could do ugly things with casting and instanceof, but this design is rather putrid. Try moving towards an object oriented model.
interface Drawable {
int getX();
int getY();
void moveDown(int numSpaces);
}
class Hamburger implements Drawable {
private int x;
private int y;
public Hamburger(final int xPos, final int yPos) {
x = xPos;
y = yPos;
}
#Override
public void moveDown(final int numSpaces) {
// eg negative number, off the screen
if(isValid(numSpaces)) {
setY(getY() - numSpaces);
}
}
}
class Positioner {
public static void moveMyObjects(final Drawable[][] objs) {
for(Drawable[] rows : objs) {
for(Drawable col : rows) {
// clearly Object doesn't have a getY() method, so you should create your own interface and implement it
col.moveDown(12);
}
}
}
}