Question

我对JOGL很新，所以请原谅这个问题的noobness。

我正在尝试编写一段玩具代码，使用GLCanvas输出单个方块，GLCanvas随机放置在画布上。但是，显示功能似乎被调用两次（因此出现两个方块，而不是一个）。这是代码。我哪里出错了？

RandomPoint类：

import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;


public class RandomPoints extends Frame implements GLEventListener{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public int HEIGHT;
    public int WIDTH;
    private GLCanvas canvas;
    //private Animator animator;
    public RandomPoints(){
        HEIGHT = 300;
        WIDTH = 300;
        GLProfile profile = GLProfile.getDefault();
        GLCapabilities cap = new GLCapabilities(profile);
        canvas = new GLCanvas(cap);
        add(canvas, BorderLayout.CENTER);
        canvas.addGLEventListener(this);
        System.out.println("Probe");
        addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                //animator.stop();
                System.exit(0);
            }
        });     
    }

    @Override
    public void display(GLAutoDrawable arg0) {
        //TODO Auto-generated method stub
        GL2 gl = arg0.getGL().getGL2();
        float red = (float) Math.random();
        float blue = (float) Math.random();
        float green = (float) Math.random();
        int x = (int)(Math.random()*WIDTH);
        int y = (int)(Math.random()*HEIGHT);
        gl.glColor3f(red, green, blue);
        gl.glBegin(GL2.GL_POLYGON);
            gl.glVertex2i(x, y);
            gl.glVertex2i(x+10, y);
            gl.glVertex2i(x+10, y+10);
            gl.glVertex2i(x, y+10);
        gl.glEnd();
        System.out.println(x+" "+y+" "+red+" "+green+" "+blue);



    }

    @Override
    public void dispose(GLAutoDrawable arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void init(GLAutoDrawable arg0) {
        // TODO Auto-generated method stub
        GL2 gl = arg0.getGL().getGL2();
        gl.glColor3f(0.0f, 0.0f, 0.0f);
        gl.glClearColor(1, 1, 1, 0);
        gl.glClear(GL2.GL_COLOR_BUFFER_BIT);
        //animator = new Animator(canvas);
        //animator.start();
    }

    @Override
    public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3, int arg4) {
        // TODO Auto-generated method stub
        WIDTH = arg3; HEIGHT = arg4;
        GL2 gl = arg0.getGL().getGL2();
        gl.glMatrixMode(GL2.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glOrtho(0, WIDTH, 0, HEIGHT, -1, 1);
    }

}

GLTest类（驱动程序）

public class GLTest {
    public static void main(String args[]){
        RandomPoints point = new RandomPoints();
        point.setSize(300,300);
        point.setVisible(true);
    }
}

提前致谢！

Answer 1

我刚刚测试了你的代码，我只看到一个正方形。但是，最好还清除display（）方法中的颜色缓冲区。你应该看一下我的例子here。如果你真的想要为你的绘画设置动画，你应该使用动画师。如果你想获得更准确和更快的回复，请在official forum上发布关于JOGL的问题，因为只有极少数的维护者来到这里。

JOGL显示功能被调用了两次

1 个答案: