Question

在我的LibGDX游戏中，我试图找到一种基于.PNG图像文件中像素创建地图的方法。我正在使用BufferedImage类将图像中的RGB值转换并存储到Array中，然后Array根据其值返回Tile。但是，包含所有Tiles的Array只会填充“null”值。

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) {

}

}

如果我添加System.out.println(tiles[1]) - 这将在控制台中打印'null'。

下面的代码在一个单独的类中，我调用generate方法并将tiles数组存储在Iterator中。在draw方法中，if语句用于确定Iterator中的当前Tile是否为null，如果是，则不会绘制/呈现tile。在游戏中，我的播放器只有一个白色屏幕，表示tiles[]数组中的所有值都等于'null'。如果要删除if语句，我会得到NullPointerException。

显示方法

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);
    }
}

如果我添加：

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));
}

然后我收到NullPointerException。

Answer 1

你的瓷砖是有条件填充的（这意味着它们有可能不会被填充）

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));
    }
}

Answer 2

问题出在levelPixels数组。它应该以{{1}}方法填充，因此您应该在调用此方法后检查此数组的值是否不等于image.getRGB()。无论如何，很明显这个数组的值都不等于0或0x24ff，这就是为什么0x8b8b8b数组只是Level.tiles的数组

请你试试以下内容：

nulls

还请初始化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)); } }：manager

数组填充了＆＃39; null＆＃39; - LibGDX

2 个答案: