为什么当我使用 createBufferStrategy(3) 时会抛出 illegalArgumentExceptio

Question

我开始使用Java创建一个游戏。在我的 render(( 方法中，我有一个缓冲区策略，有三个缓冲区。但是，当我运行它时，我收到此错误。

Exception in thread "Thread-1" java.lang.IllegalArgumentException: Width (0) and height (0) cannot be <= 0
    at java.awt.image.DirectColorModel.createCompatibleWritableRaster(DirectColorModel.java:1016)
    at sun.java2d.opengl.CGLGraphicsConfig.createCompatibleImage(CGLGraphicsConfig.java:200)
    at java.awt.GraphicsConfiguration.createCompatibleImage(GraphicsConfiguration.java:178)
    at sun.awt.image.SunVolatileImage.getBackupImage(SunVolatileImage.java:236)
    at sun.awt.image.VolatileSurfaceManager.getBackupSurface(VolatileSurfaceManager.java:263)
    at sun.awt.image.VolatileSurfaceManager.initialize(VolatileSurfaceManager.java:126)
    at sun.awt.image.SunVolatileImage.<init>(SunVolatileImage.java:88)
    at sun.awt.image.SunVolatileImage.<init>(SunVolatileImage.java:98)
    at sun.awt.image.SunVolatileImage.<init>(SunVolatileImage.java:109)
    at sun.java2d.opengl.CGLGraphicsConfig.createBackBufferImage(CGLGraphicsConfig.java:356)
    at sun.lwawt.LWCanvasPeer.createBuffers(LWCanvasPeer.java:62)
    at java.awt.Component$FlipBufferStrategy.createBuffers(Component.java:4016)
    at java.awt.Component$FlipBufferStrategy.<init>(Component.java:3956)
    at java.awt.Component$FlipSubRegionBufferStrategy.<init>(Component.java:4479)
    at java.awt.Component.createBufferStrategy(Component.java:3833)
    at java.awt.Canvas.createBufferStrategy(Canvas.java:194)
    at java.awt.Component.createBufferStrategy(Component.java:3756)
    at java.awt.Canvas.createBufferStrategy(Canvas.java:169)
    at com.game.framework.Game.render(Game.java:79)
    at com.game.framework.Game.run(Game.java:58)
    at java.lang.Thread.run(Thread.java:744)

下面是使用 render(( 方法的完整类：

package com.game.framework;
import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.image.BufferStrategy;
public class Game extends Canvas implements Runnable {
    private static final long serialVersionUID = 2956560507546666478L;
    private Thread thread;
    private boolean running = false;
    public static final int WIDTH = 640, HEIGHT = WIDTH / 12 * 9;
    public Game() {
        new Window(WIDTH, HEIGHT, "UNKNOWN", this);
    }
    public synchronized void start() {
        thread = new Thread(this);
        thread.start();
        running = true;
    }
    public synchronized void stop() {
        try {
            thread.join();
            running = false;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void run() {
        long lastTime = System.nanoTime();
        long timer = System.currentTimeMillis();
        double amountOfTicks = 60.0;
        double ns = 1000000000 / amountOfTicks;
        double delta = 0;
        int frames = 0;
        while (running) {
            long now = System.nanoTime();
            delta += (now - lastTime) / ns;
            lastTime = now;
            while (delta >= 1) {
                tick();
                delta--;
            }
            if (running)
                render();
            frames++;
            if (System.currentTimeMillis() - timer > 1000) {
                timer += 1000;
                System.out.println("FPS: " + frames);
                frames = 0;
            }
        }
        stop();
    }
    private void tick() { }
    private void render() {
        BufferStrategy bs = this.getBufferStrategy();
        if (bs == null) {
            this.createBufferStrategy(3);
            return;
        }
        Graphics g = bs.getDrawGraphics();
    }
    public static void main(String args[]) {
        new Game();
    }
}

这是我游戏中的另一个类：

package com.game.framework;
import java.awt.Canvas;
import java.awt.Dimension;
import javax.swing.JFrame;
public class Window extends Canvas {
    private static final long serialVersionUID = 70937078350109973L;
    public Window (int width, int height, String title, Game game) {
        JFrame frame = new JFrame(title);
        frame.setPreferredSize(new Dimension(width, height));
        frame.setMaximumSize(new Dimension(width, height));
        frame.setMinimumSize(new Dimension(width, height));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setResizable(false);
        frame.setVisible(true);
        frame.add(game);
        game.start();
    }
}

我

不确定问题是什么，但这非常令人沮丧，在问题解决之前我无法继续。谢谢大家的帮助！

Answer 1

经过一些研究，我发现了您的代码对我有用但不适合您的可能原因。我正在使用Direct 3D进行渲染，而您使用的是OpenGL。

D3D 类也使用此代码来创建BufferStrategy：

public VolatileImage createBackBuffer(WComponentPeer peer) {
    Component target = (Component)peer.getTarget();
    // it is possible for the component to have size 0x0, adjust it to
    // be at least 1x1 to avoid IAE
    int w = Math.max(1, target.getWidth());
    int h = Math.max(1, target.getHeight());
    return new SunVolatileImage(target, w, h, Boolean.TRUE);
}

如您所见，它将宽度和高度设置为至少1以避免IllegalArgumentException 。

该类的 OpenGL 版本不会：

@Override
public VolatileImage createBackBufferImage(Component target,
                                           long backBuffer) {
    return new SunVolatileImage(target,
                                target.getWidth(), target.getHeight(),
                                Boolean.TRUE);
}

因此，如果您仍然想使用 OpenGl，那么您需要绕过短时间，其中 Canvas 的大小尚未设置**(即宽度和高度0(自行设置：

private void render() {
    if (getWidth() == 0 || getHeight() == 0) {
        return;
    }
    BufferStrategy bs = this.getBufferStrategy();
    if (bs == null) {
        this.createBufferStrategy(3);
        return;
    }
    Graphics g = bs.getDrawGraphics();
}

** 似乎有很短的时间，Game画布没有"具有"正确的尺寸。它的大小在那里0x0，但稍后会更新为634x449(在游戏循环大约 3 次迭代后(。