import java.awt.*;
import java.awt.event.*;

import javax.media.opengl.*;
import javax.swing.*;

/**
 * Example JOGL application showing bug when drawing a line strip with flat shading
 * turned on. The bug occurs when using GLJPanel under the Windows Vista operating system.
 * The bug does not occur under Windows XP.
 *
 * Run environment: 
 * Machine  : n/a
 * OS       : Windows Vista Business (no service pack)
 * Graphics : NVIDIA Geforce3
 * Drivers  : Microsoft Driver 6.0.6000.16386
 * JVM      : java 1.4.2_16 and 1.6.0_04
 * JOGL     : 1.1.1-rc4 and 1.1.1-rc7
 * @author Alan Michael Gay, AVS Inc.
 */
public class LineAlignmentBug extends JFrame implements GLEventListener 
{        
    public LineAlignmentBug()
    {        
        // Specify the Frame window title and initial size.
        setTitle("Line Alignment bug");

        // Create a listener object that will cause the application
        // to exit when the user dismisses the Frame window.
        this.addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });   

        // Use the default capabilities.
        GLCapabilities capabilities = new GLCapabilities();

        GLJPanel canvas = new GLJPanel(capabilities);
        canvas.addGLEventListener(this);
            
        this.getContentPane().add(canvas);
    }
        
    /**
     * Sets the OpenGL color using the specified java.awt.Color.
     * @param gl The OpenGL context whose color is to be set.
     * @param color The color to set.
     */
    private void setColor(GL gl, Color color)
    {        
        float red   = color.getRed()/255.0f;
        float green = color.getGreen()/255.0f;
        float blue  = color.getBlue()/255.0f;        
        gl.glColor3f(red, green, blue);              
    }
    
    
    /**
     * Implementation of GLEventListener.display
     * Draws a triangle with a border using a line strip.
     */
    public void display(GLAutoDrawable arg0)
    {
        GL gl = arg0.getGL();
        
        gl.glClear(GL.GL_COLOR_BUFFER_BIT);
        gl.glMatrixMode(GL.GL_MODELVIEW);
                
        // BUG
        // Line is drawn in the incorrect position when turning flat shading on.
        gl.glShadeModel(GL.GL_FLAT);
        
        //
        // Triangles
        //        
        setColor(gl, Color.GREEN);
               
        gl.glBegin(GL.GL_TRIANGLES);
        
        gl.glVertex3f(-0.5f, 0.5f, 0.0f);
        gl.glVertex3f(0.5f, 0.5f, 0.0f);
        gl.glVertex3f(0.5f, -0.5f, 0.0f);
      
        gl.glEnd();    
                
        ///
        // Line strip
        //        
        setColor(gl, Color.RED);
          
        gl.glBegin(GL.GL_LINE_STRIP);        
        gl.glVertex3f(-0.5f, 0.5f, 0.0f);
        gl.glVertex3f(0.5f, 0.5f, 0.0f);                                     
        gl.glVertex3f(0.5f, -0.5f, 0.0f);
        gl.glVertex3f(-0.5f, 0.5f, 0.0f);
        gl.glEnd();    
    }
    

    public void init(GLAutoDrawable arg0)
    {
    }

    public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3, int arg4)
    {    
    }

    public void displayChanged(GLAutoDrawable arg0, boolean arg1, boolean arg2)
    {  
    }

    /**
     * The main() method is called when the Java Virtual Machine starts up. It
     * just creates and displays an instance of the application.
     */
    public static void main(String args[])
    {
        LineAlignmentBug app = new LineAlignmentBug();
        app.pack();
        app.setSize(300, 300);
        app.setVisible(true);
    }
}