import java.applet.Applet;
import java.awt.Graphics;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;

// must import jgl.GL....
import jgl.GL;
import jgl.GLU;
import jgl.GLAUX;

public class checker extends Applet
		     implements ComponentListener {
    // must use GL to use jGL.....
    // and use GLU to use the glu functions....
    // remember to give GL to initialize GLU
    // and use GLAUX to use the aux functions.....
    // remember to give GL to initialize GLAUX
    GL myGL = new GL ();
    GLU myGLU = new GLU (myGL);
    GLAUX myAUX = new GLAUX (myGL);

    private static final int checkImageWidth = 64;
    private static final int checkImageHeight = 64;
    private byte checkImage [][][] =
    		   new byte [checkImageWidth][checkImageHeight][3];

    private void makeCheckImage () {
    	int i, j, r;
	byte c;

	for (i = 0; i < checkImageWidth; i++) {
	    for (j = 0; j < checkImageHeight; j++) {
	    	if ((((i & 0x8) == 0) ^ ((j & 0x8)) == 0)) { c = (byte)255;
		} else { c = (byte)0; }
		checkImage [i][j][0] = c;
		checkImage [i][j][1] = c;
		checkImage [i][j][2] = c;
	    }
	}
    }

    private void myinit () {
	myGL.glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
	myGL.glEnable (GL.GL_DEPTH_TEST);
	myGL.glDepthFunc (GL.GL_LEQUAL);
	makeCheckImage ();
	myGL.glPixelStorei (GL.GL_UNPACK_ALIGNMENT, 1);
	myGL.glTexImage2D (GL.GL_TEXTURE_2D, 0, 3, checkImageWidth,
	    checkImageHeight, 0, GL.GL_RGB, GL.GL_UNSIGNED_BYTE, checkImage);
	myGL.glTexParameterf (GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP);
	myGL.glTexParameterf (GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP);
	myGL.glTexParameterf (GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_NEAREST);
	myGL.glTexParameterf (GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_NEAREST);
	myGL.glTexEnvf (GL.GL_TEXTURE_ENV, GL.GL_TEXTURE_ENV_MODE, GL.GL_DECAL);
	myGL.glEnable (GL.GL_TEXTURE_2D);
	myGL.glShadeModel (GL.GL_FLAT);
    }

    private void display () {
	myGL.glClear (GL.GL_COLOR_BUFFER_BIT);
	myGL.glBegin (GL.GL_QUADS);
	myGL.glTexCoord2f (0.0f, 0.0f);
	myGL.glVertex3f (-2.0f, -1.0f, 0.0f);
	myGL.glTexCoord2f (0.0f, 1.0f);
	myGL.glVertex3f (-2.0f, 1.0f, 0.0f);
	myGL.glTexCoord2f (1.0f, 1.0f);
	myGL.glVertex3f (0.0f, 1.0f, 0.0f);
	myGL.glTexCoord2f (1.0f, 0.0f);
	myGL.glVertex3f (0.0f, -1.0f, 0.0f);

	myGL.glTexCoord2f (0.0f, 0.0f);
	myGL.glVertex3f (1.0f, -1.0f, 0.0f);
	myGL.glTexCoord2f (0.0f, 1.0f);
	myGL.glVertex3f (1.0f, 1.0f, 0.0f);
	myGL.glTexCoord2f (1.0f, 1.0f);
	myGL.glVertex3f (2.41421f, 1.0f, -1.41421f);
	myGL.glTexCoord2f (1.0f, 0.0f);
	myGL.glVertex3f (2.41421f, -1.0f, -1.41421f);
	myGL.glEnd ();
	myGL.glFlush ();
    }

    public void componentMoved (ComponentEvent e) {}
    public void componentShown (ComponentEvent e) {}
    public void componentHidden (ComponentEvent e) {}

    public void componentResized (ComponentEvent e) {
	// get window width and height by myself
	myReshape (getSize ().width, getSize ().height);
	display ();
	repaint ();
    }

    private void myReshape (int w, int h) {
        myGL.glViewport (0, 0, w, h);
        myGL.glMatrixMode (GL.GL_PROJECTION);
        myGL.glLoadIdentity ();
	myGLU.gluPerspective (60.0, 1.0 * (double)w/(double)h, 1.0, 30.0);
        myGL.glMatrixMode (GL.GL_MODELVIEW);
        myGL.glLoadIdentity ();
	myGL.glTranslatef (0.0f, 0.0f, -3.6f);
    }

    public void update (Graphics g) {
    	// skip the clear screen command....
	paint (g);
    }

    public void paint (Graphics g) {
    	// STRANGE if call display here, it will be never stoped
	myGL.glXSwapBuffers (g, this);
    }

    public void init () {
	myAUX.auxInitPosition (0, 0, 500, 500);
	myAUX.auxInitWindow (this);
	myinit ();

	// as call auxReshapeFunc()
	addComponentListener (this);
	myReshape (getSize ().width, getSize ().height);

	// call display as call auxMainLoop(display);
        display ();
    }

}