JOGL Depth Buffer Not Working

[Kearnel]

Hi, I've recently discovered a bug in some simple JOGL (Java Open Graphics Library) code that I was writing and can't figure out how to fix it. It seems that the depth buffer isn't working at all. In my code there is a stationary triangle and a moving square, when the square passes behind the triangle it looks like it's in front of the triangle instead of behind!

Here is the output:

init:
Deleting: /home/austin/NetBeansProjects/JOGLCoreClasses/build/built-jar.properties
deps-jar:
Updating property file: /home/austin/NetBeansProjects/JOGLCoreClasses/build/built-jar.properties
Compiling 1 source file to /home/austin/NetBeansProjects/JOGLCoreClasses/build/classes
compile:
run:
INIT GL IS: com.sun.opengl.impl.GLImpl
do_wait: drmWaitVBlank returned -1, IRQs don't seem to be working correctly.
Try adjusting the vblank_mode configuration parameter.
BUILD SUCCESSFUL (total time: 18 seconds)

Here is my code:

package Example;

import com.sun.opengl.util.Animator;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;



/**
 * JOGLCoreClasses.java <BR>
 * author: Brian Paul (converted to Java by Ron Cemer and Sven Goethel) <P>
 *
 * This version is equal to Brian Paul's version 1.2 1999/10/21
 */
public class JOGLExample implements GLEventListener {

    float x = 0;

    public static void main(String[] args) {
        Frame frame = new Frame("Simple JOGL Application");
        GLCanvas canvas = new GLCanvas();

        canvas.addGLEventListener(new JOGLCoreClasses());
        frame.add(canvas);
        frame.setSize(640, 480);
        final Animator animator = new Animator(canvas);
        frame.addWindowListener(new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                // Run this on another thread than the AWT event queue to
                // make sure the call to Animator.stop() completes before
                // exiting
                new Thread(new Runnable() {

                    public void run() {
                        animator.stop();
                        System.exit(0);
                    }
                }).start();
            }
        });
        // Center frame
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        animator.start();
    }

    public void init(GLAutoDrawable drawable) {
        // Use debug pipeline
        // drawable.setGL(new DebugGL(drawable.getGL()));

        GL gl = drawable.getGL();
        System.err.println("INIT GL IS: " + gl.getClass().getName());

        // Enable VSync
        gl.setSwapInterval(1);

        // Setup the drawing area and shading mode
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        gl.glShadeModel(GL.GL_SMOOTH); // try setting this to GL_FLAT and see what happens.
    }

    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
        GL gl = drawable.getGL();
        GLU glu = new GLU();

        if (height <= 0) { // avoid a divide by zero error!
        
            height = 1;
        }
        final float h = (float) width / (float) height;
        gl.glViewport(0, 0, width, height);
        gl.glMatrixMode(GL.GL_PROJECTION);
        gl.glLoadIdentity();
        glu.gluPerspective(45.0f, h, 1.0, 20.0);
        gl.glMatrixMode(GL.GL_MODELVIEW);
        gl.glLoadIdentity();
    }

    public void display(GLAutoDrawable drawable) {
        x += 0.1;
        GL gl = drawable.getGL();

        // Clear the drawing area
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        
        // Reset the current matrix to the "identity"
        gl.glLoadIdentity();

        // Move the "drawing cursor" around
        gl.glTranslatef(-1.5f, 0.0f, -6.0f);

        // Drawing Using Triangles
        gl.glBegin(GL.GL_TRIANGLES);
            gl.glColor3f(1.0f, 0.0f, 0.0f);    // Set the current drawing color to red
            gl.glVertex3f(0.0f, 1.0f, 0.0f);   // Top
            gl.glColor3f(0.0f, 1.0f, 0.0f);    // Set the current drawing color to green
            gl.glVertex3f(-1.0f, -1.0f, 0.0f); // Bottom Left
            gl.glColor3f(0.0f, 0.0f, 1.0f);    // Set the current drawing color to blue
            gl.glVertex3f(1.0f, -1.0f, 0.0f);  // Bottom Right
        // Finished Drawing The Triangle
        gl.glEnd();

        // Move the "drawing cursor" to another position
        gl.glLoadIdentity();
        gl.glTranslatef(0.0f, 0.0f, -6.0f);
        gl.glRotatef(x, 0, 1, 0);
        gl.glTranslatef(1.5f, 0.0f, 0.0f);
        // Draw A Quad
        gl.glBegin(GL.GL_QUADS);
            gl.glColor3f(0.5f, 0.5f, 1.0f);    // Set the current drawing color to light blue
            gl.glVertex3f(-1.0f, 1.0f, 0.0f);  // Top Left
            gl.glVertex3f(1.0f, 1.0f, 0.0f);   // Top Right
            gl.glVertex3f(1.0f, -1.0f, 0.0f);  // Bottom Right
            gl.glVertex3f(-1.0f, -1.0f, 0.0f); // Bottom Left
        // Done Drawing The Quad
        gl.glEnd();

        // Flush all drawing operations to the graphics card
        gl.glFlush();
    }

    public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
    }
}

[Kearnel]

Can some one please help me.