java - GL11.glMatrixMode() 的 LWJGL 错误 "function is not supported"

Question

我将先发布代码，然后发布以下问题:

import java.util.Properties;

import org.lwjgl.Sys;
import org.lwjgl.input.Keyboard;
import org.lwjgl.input.Mouse;
import org.lwjgl.opengl.ContextAttribs;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.PixelFormat;

import ref.Reference;
import ref.Settings;

public class Main implements Runnable {

private static int width;
private static int height;

private long lastframe;
private int fps;
private long lastfps;

private float rotation = 0;
private float x = 400;
private float y = 300;

private boolean running = false;
private Thread thread;
private static Properties settings = new Properties();

public static void main(String[] args) {
    Main game = new Main();
    Settings.load();
    settings = Settings.getSettings();  
    game.initDisplay(); 
    game.initGL();  
    game.start();
}

public void run() { 
    System.out.println("Start");    
    getDelta();
    lastfps = getTime();    
    while (!Display.isCloseRequested()) {           
        if (running) {
            int delta = getDelta();             
            tick(delta);                
            Display.sync(60);
        }           
        render();           
        updateFPS();            
        Display.update();
    }   
    if (Display.isCloseRequested()) {
        stop();
        cleanup();
    }
}

private void updateFPS() {
    if (getTime() - lastfps > 1000) {
        System.out.println("FPS: " + fps);
        fps = 0;
        lastfps += 1000;
    }
    fps++;
}

private void tick(int delta) {
    System.out.println("Tick"); 
    rotation += 0.15f * delta;  
    if (Keyboard.isKeyDown(Keyboard.KEY_LEFT)) x -= 0.35f * delta;
    if (Keyboard.isKeyDown(Keyboard.KEY_RIGHT)) x += 0.35f * delta;
    if (Keyboard.isKeyDown(Keyboard.KEY_UP)) y -= 0.35f * delta;
    if (Keyboard.isKeyDown(Keyboard.KEY_DOWN)) y += 0.35f * delta;
    if (x < 0) x = 0;
    if (x > 800) x = 800;
    if (y < 0) y = 0;
    if (y > 600) y = 600;       
}

private void render() {
    System.out.println("Render");
    GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
    GL11.glColor3f(0.5f, 0.5f, 1.0f);
    GL11.glPushMatrix();
    GL11.glTranslatef(x, y, 0);
    GL11.glRotatef(rotation, 0f, 0f, 0f);
    GL11.glBegin(GL11.GL_QUADS);
    GL11.glVertex2f(x - 50, y - 50);
    GL11.glVertex2f(x + 50, y - 50);
    GL11.glVertex2f(x + 50, y + 50);
    GL11.glVertex2f(x - 50, y + 50);
    GL11.glEnd();
    GL11.glPopMatrix();
}

private void cleanup() {
    Mouse.destroy();
    Keyboard.destroy();
    Display.destroy();
}

public void initGL() {  
    System.out.println("initGL");
    GL11.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);  
    GL11.glMatrixMode(GL11.GL_PROJECTION);
    GL11.glLoadIdentity();
    GL11.glOrtho(0, 800, 0, 600, 1, -1);
    GL11.glMatrixMode(GL11.GL_MODELVIEW);
}

public void initDisplay() {
    System.out.println("initDisplay");

    try {
        width = Integer.parseInt(settings.getProperty("width"));
        height = Integer.parseInt(settings.getProperty("height"));      
        Display.setDisplayMode(new DisplayMode(width, height));
        Display.setTitle(Reference.WINDOWTITLE);
        Display.create();
        Keyboard.create();
        Mouse.create();
    } catch (Exception e) {

    }
}

public void start() {
    if (running) return;
    running = true;
    thread = new Thread(this, "Display");
    thread.start();
}

public void stop() {
    if (!running) return;
    running = false;
    try {
        thread.join();
    } catch (Exception e) {

    }
}

private long getTime() {
    return (Sys.getTime() * 1000) / Sys.getTimerResolution();
}

public int getDelta() {
    long time = getTime();
    int delta = (int) (time - lastframe);
    lastframe = time;   
    return delta;
}

}

现在启动时出现错误:

initDisplay
initGL
Exception in thread "main" java.lang.IllegalStateException: Function is not supported
    at org.lwjgl.BufferChecks.checkFunctionAddress(BufferChecks.java:58)
    at org.lwjgl.opengl.GL11.glMatrixMode(GL11.java:2075)
    at Main.initGL(Main.java:127)
    at Main.main(Main.java:41)

这基本上是来自 LWJGL Wiki 的代码，我只是复制它以查看线程是否工作并遇到了这个。这对我来说是新事物，所以任何人都可以帮助并告诉我什么是不正确的吗？因为我不明白。

第 127 行是 initGL() 的第一行(我为此删除了空行，因此它不再是第 127 行，但这是发生错误的行):

GL11.glMatrixMode(GL11.GL_PROJECTION);

没有线程也能正常工作

Answer 1

OpenGL 调用(来自一个 GL 上下文)只能在一个线程上运行。您的代码在同一 GL 上下文中通过两个不同的线程运行 OpenGL 代码。在默认线程上运行 game.initDisplay() 和 game.initGL()，并在您自己的新线程上运行剩余的 OpenGL 代码。您要么需要确保所有 OpenGL 调用都是从一个线程进行，要么研究上下文共享。我会选择单线程，直到这被证明是一个问题。