Array is filled with 'null' - LibGDX

0
votes

In my LibGDX game, I am trying to work out a way to create a map based on the pixels in a .PNG image file. I am using the BufferedImage class to convert and store the RGB values from the image into an Array, which then returns a Tile based on its value. However, the Array that contains all of the Tiles is just filled with 'null' values.

import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;

import com.badlogic.gdx.assets.AssetManager;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Vector2;
import com.survivegameandroidtest.survive.player.Player;
import com.survivegameandroidtest.survive.tiles.ConcreteTile;
import com.survivegameandroidtest.survive.tiles.GrassTile;

public class Level {

Tile[] tiles;
int[] levelPixels;
AssetManager manager;
Player player;
SpriteBatch batch;

public Level(String path) {
    try {
        BufferedImage image = ImageIO.read(Level.class.getResource(path));
        int width = image.getWidth();
        int height = image.getHeight();
        tiles = new Tile[width * height];
        levelPixels = new int[width * height];
        image.getRGB(0, 0, width, height, levelPixels, 0, width);
        } catch(IOException e) {
        e.printStackTrace();
        System.out.println("Level could not load");
    }
}


//GRASS = 0x24ff00
//CONCRETE = 0x8b8b8b
public void generateLevel() {
    for(int i = 0; i < levelPixels.length; i++) {
        if(levelPixels[i] == 0x24ff) tiles[i] = new GrassTile(manager.get("grass.png", Texture.class), new Vector2(i * 10, i * 10), new Vector2(10,10));
        if(levelPixels[i] == 0x8b8b8b) tiles[i] = new ConcreteTile(manager.get("concrete.png", Texture.class), new Vector2(i * 10, i * 10), new Vector2(10,10));
    }
}

public void update() {

}

public void draw(SpriteBatch batch) {

}

}

If I add a System.out.println(tiles[1]) - this will print 'null' in the console.

This code below is in a separate class, where I call the generate method and store the tiles Array in an Iterator. In the draw method, an if-statement is used to determine whether the current Tile in the Iterator is null, if it is, then it doesn't draw/render the tile. On the game, there is only a white screen with my player, indicating that all of the values in the tiles[] Array are equal to 'null'. If the if-statement was to be removed, I would get a NullPointerException.

SHOW METHOD

level = new Level("/level.png");
tiles = new ArrayList<Tile>();

for(int i = 0; i < level.tiles.length; i++) {
    level.generateLevel();
    tiles.add(level.tiles[i]);
}

RENDER METHOD

tileIterator = tiles.iterator();

while(tileIterator.hasNext()) {
    final Tile cur = tileIterator.next();
    if(cur != null) {
        cur.update();
        cur.draw(batch);
    }
}

If I add:

if (levelPixels[i] != 0x24ff || levelPixels[i] != 0x8b8b8b) {
    tiles[i] = new GrassTile(manager.get("grass.png", Texture.class),
        new Vector2(i * 10, i * 10),
        new Vector2(10, 10));
}

Then I receive a NullPointerException.

2
javaarrayslibgdxrgbbufferedimage

2 Answers

1
votes

your tiles are conditionally populated(which means there is a chance of them not getting populated)

public void generateLevel() {
    for(int i = 0; i < levelPixels.length; i++) {
        if(levelPixels[i] == 0x24ff) tiles[i] = new GrassTile(manager.get("grass.png", Texture.class), new Vector2(i * 10, i * 10), new Vector2(10,10));
        if(levelPixels[i] == 0x8b8b8b) tiles[i] = new ConcreteTile(manager.get("concrete.png", Texture.class), new Vector2(i * 10, i * 10), new Vector2(10,10));
    }
}
0
votes

The problem is at the levelPixels array. It should be filled at the image.getRGB() method, so you should start with checking if values of this array are not equal to 0 after calling this method. Anyway, it's obvious that none of the values of this array is equal to 0x24ff or 0x8b8b8b, that is why Level.tiles array remains just array of nulls

Can you please try the following:

for (int i = 0; i < levelPixels.length; i++)
{
    if (levelPixels[i] == 0x24ff) {
        tiles[i] = new GrassTile(manager.get("grass.png", Texture.class),
                new Vector2(i * 10, i * 10),
                new Vector2(10, 10));
    } else if (levelPixels[i] == 0x8b8b8b) {
        tiles[i] = new ConcreteTile(manager.get("concrete.png", Texture.class),
                new Vector2(i * 10, i * 10),
                new Vector2(10, 10));
    } else {
        tiles[i] = new GrassTile(manager.get("grass.png", Texture.class),
                new Vector2(i * 10, i * 10),
                new Vector2(10, 10));
    }
}

And also please init manager: AssetManager manager = new AssetManager();