3D 图片无法加载 Java

Question

我尝试在 3D 生成器中展示一些 Blockarts。但我无法弄清楚这个错误：

javax.imageio.IIOException: Can't read input file!
at java.desktop/javax.imageio.ImageIO.read(ImageIO.java:1310)
at Texture.load(Texture.java:20)
at Texture.<init>(Texture.java:15)
at Texture.<clinit>(Texture.java:29)
at Game.<init>(Game.java:45)
at Game.main(Game.java:103)
javax.imageio.IIOException: Can't read input file!

当我启动程序时，整个世界都出现黑色块： 启动程序后的屏幕截图

我想做一个 3D 引擎，你可以在其中走动在房间里。所以这个块不会为我渲染。

这是我的代码：

Class:Texture

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;

public class Texture {
  public int[] pixels;
  private String loc;
  public final int SIZE;

public Texture(String location, int SIZE) {
    loc = location;
    this.SIZE = SIZE;
    pixels = new int[SIZE * SIZE];
    load();
}

private void load() {
    try {
        BufferedImage image = ImageIO.read(new File(loc));
        int w = image.getWidth();
        int h = image.getHeight();
        image.getRGB(0, 0, w, h, pixels, 0, w);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static Texture wood = new Texture("block1.png", 64);
public static Texture brick = new Texture("block2.png", 64);
public static Texture bluestone = new Texture("block3.png", 64);
public static Texture stone = new Texture("block1.png", 64);

}

Class Game:

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.util.ArrayList;
import javax.swing.JFrame;

public class Game extends JFrame implements Runnable{

 private static final long serialVersionUID = 1L;
 public int mapWidth = 15;
 public int mapHeight = 15;
 private Thread thread;
 private boolean running;
 private BufferedImage image;
 public int[] pixels;
 public ArrayList<Texture> textures;
 public Camera camera;
 public Screen screen;
 public static int[][] map =
        {
               {1,1,1,1,1,1,1,1,2,2,2,2,2,2,2},
               {1,0,0,0,0,0,0,0,2,0,0,0,0,0,2},
               {1,0,3,3,3,3,3,0,0,0,0,0,0,0,2},
               {1,0,3,0,0,0,3,0,2,0,0,0,0,0,2},
               {1,0,3,0,0,0,3,0,2,2,2,0,2,2,2},
               {1,0,3,0,0,0,3,0,2,0,0,0,0,0,2},
               {1,0,3,3,0,3,3,0,2,0,0,0,0,0,2},
               {1,0,0,0,0,0,0,0,2,0,0,0,0,0,2},
               {1,1,1,1,1,1,1,1,4,4,4,0,4,4,4},
               {1,0,0,0,0,0,1,4,0,0,0,0,0,0,4},
               {1,0,0,0,0,0,1,4,0,0,0,0,0,0,4},
               {1,0,0,0,0,0,1,4,0,3,3,3,3,0,4},
               {1,0,0,0,0,0,1,4,0,3,3,3,3,0,4},
               {1,0,0,0,0,0,0,0,0,0,0,0,0,0,4},
               {1,1,1,1,1,1,1,4,4,4,4,4,4,4,4}

        };
public Game() {
    thread = new Thread(this);
    image = new BufferedImage(640, 480, BufferedImage.TYPE_INT_RGB);
    pixels = ((DataBufferInt)image.getRaster().getDataBuffer()).getData();
    textures = new ArrayList<Texture>();
    textures.add(Texture.wood);
    textures.add(Texture.brick);
    textures.add(Texture.bluestone);
    textures.add(Texture.stone);
    camera = new Camera(4.5, 4.5, 1, 0, 0, -.66);
    screen = new Screen(map, mapWidth, mapHeight, textures, 640, 480);
    addKeyListener(camera);
    setSize(640, 480);
    setResizable(false);
    setTitle("3D Engine");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBackground(Color.black);
    setLocationRelativeTo(null);
    setVisible(true);
    start();
}
private synchronized void start() {
    running = true;
    thread.start();
}
public synchronized void stop() {
    running = false;
    try {
        thread.join();
    } catch(InterruptedException e) {
        e.printStackTrace();
    }
}
public void render() {
    BufferStrategy bs = getBufferStrategy();
    if(bs == null) {
        createBufferStrategy(3);
        return;
    }
    Graphics g = bs.getDrawGraphics();
    g.drawImage(image, 0, 0, image.getWidth(), image.getHeight(), null);
    bs.show();
}
public void run() {
    long lastTime = System.nanoTime();
    final double ns = 1000000000.0 / 60.0;//60 times per second
    double delta = 0;
    requestFocus();
    while(running) {
        long now = System.nanoTime();
        delta = delta + ((now-lastTime) / ns);
        lastTime = now;
        while (delta >= 1)//Make sure update is only happening 60 times a second
        {
            //handles all of the logic restricted time
            screen.update(camera, pixels);
            camera.update(map);
            delta--;
        }
        render();//displays to the screen unrestricted time
    }
}
public static void main(String [] args) {
    Game game = new Game();
}

}

Answer 1

您加载纹理时遇到问题。评估如何处理根本原因（为什么无法加载图像？）和后果（你的世界是黑色的）：

根本原因

要找出图像无法加载的原因，一种措施是了解应用程序是什么图像尝试加载。像这样修改 load() 方法：

private void load() {
    File file = new File(loc);
    try {
        BufferedImage image = ImageIO.read(file);
        int w = image.getWidth();
        int h = image.getHeight();
        image.getRGB(0, 0, w, h, pixels, 0, w);
    } catch (IOException e) {
        System.out.println("ERROR: Could not load "+file.getAbsolutePath());
        e.printStackTrace();
    }
}

您可能会发现您正在错误的目录中搜索。或者访问权限设置不正确。或者文件内容已损坏。或者...

影响

当您的加载方法失败时，它不会停止程序。相反，您的游戏会继续运行。然而，像素数组不包含好的数据。

确保您有有意义的紧急默认值，以防方法失败。您可以将“错误图像”加载到像素数组中。这样你至少不应该得到一个黑色的窗口。

Answer 2

异常堆栈跟踪非常简单，应该告诉您需要做什么。它指向 ImageIO.read(File) 代码中的一个异常，如下所示：

public static BufferedImage read(File input) throws IOException {
// ... 
    if (!input.canRead()) {
        throw new IIOException("Can't read input file!"); // <-- This is the one
    }
// ... 
}

如您所见，问题在于 canRead() 返回 false，并根据方法的 API文档，这个当且仅当此抽象路径名指定的文件存在并且可由应用程序读取时，方法返回“true；否则返回false”。

您尝试读取的位置不存在您的文件，或者该文件具有禁止您的应用程序读取该文件的访问保护。就是这么简单。

我相信在 catch 块中打印 new File(loc).getAbsolutePath() 将帮助您调试实际位置以及为什么事情不起作用。最有可能的是，您根本不应该使用 File，而应在应用程序中使用嵌入式资源。