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.GLAUX;

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

    /*  Initialize light source.  */
    private void myinit () {
	float light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
	float light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };
	float light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
	/*  light_position is NOT default value  */
	float light_position[] = { 1.0f, 1.0f, 1.0f, 0.0f };

	myGL.glLightfv (GL.GL_LIGHT0, GL.GL_AMBIENT, light_ambient);
	myGL.glLightfv (GL.GL_LIGHT0, GL.GL_DIFFUSE, light_diffuse);
	myGL.glLightfv (GL.GL_LIGHT0, GL.GL_SPECULAR, light_specular);
	myGL.glLightfv (GL.GL_LIGHT0, GL.GL_POSITION, light_position);
    
	myGL.glFrontFace (GL.GL_CW);
	myGL.glEnable (GL.GL_LIGHTING);
	myGL.glEnable (GL.GL_LIGHT0);
	myGL.glEnable (GL.GL_AUTO_NORMAL);
	myGL.glEnable (GL.GL_NORMALIZE);
	myGL.glDepthFunc (GL.GL_LESS);
	myGL.glEnable (GL.GL_DEPTH_TEST);
    }

    private void display () {
	double eqn[] = { 1.0, 0.0, -1.0, 1.0 };
	boolean two_side_on[] = { GL.GL_TRUE };
	boolean two_side_off[] = { GL.GL_FALSE };
	float mat_diffuse[] = { 0.8f, 0.8f, 0.8f, 1.0f };
	float back_diffuse[] = { 0.8f, 0.2f, 0.8f, 1.0f };

	myGL.glClear (GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

	myGL.glPushMatrix ();
	myGL.glClipPlane (GL.GL_CLIP_PLANE0, eqn);  /*  slice objects   */
	myGL.glEnable (GL.GL_CLIP_PLANE0); 

	myGL.glPushMatrix ();
	myGL.glTranslatef (0.0f, 2.0f, 0.0f);
	myAUX.auxSolidTeapot (1.0);		/*  one-sided lighting  */
	myGL.glPopMatrix ();

	/*  two-sided lighting, but same material  */
	myGL.glLightModeli (GL.GL_LIGHT_MODEL_TWO_SIDE, GL.GL_TRUE);
	myGL.glMaterialfv (GL.GL_FRONT_AND_BACK, GL.GL_DIFFUSE, mat_diffuse);
	myGL.glPushMatrix ();
	myGL.glTranslatef (0.0f, 0.0f, 0.0f);
	myAUX.auxSolidTeapot (1.0);
	myGL.glPopMatrix ();

	/*  two-sided lighting, two different materials	*/
	myGL.glMaterialfv (GL.GL_FRONT, GL.GL_DIFFUSE, mat_diffuse);
	myGL.glMaterialfv (GL.GL_BACK, GL.GL_DIFFUSE, back_diffuse);
	myGL.glPushMatrix ();
	myGL.glTranslatef (0.0f, -2.0f, 0.0f);
	myAUX.auxSolidTeapot (1.0);
	myGL.glPopMatrix ();

	myGL.glLightModeli (GL.GL_LIGHT_MODEL_TWO_SIDE, GL.GL_FALSE);
	myGL.glDisable (GL.GL_CLIP_PLANE0);
	myGL.glPopMatrix ();
	myGL.glFlush();
    }

    private void myReshape (int w, int h) {
        myGL.glViewport (0, 0, w, h);
        myGL.glMatrixMode (GL.GL_PROJECTION);
        myGL.glLoadIdentity ();
        if (w <= h) {
            myGL.glOrtho (-4.0f, 4.0f,
                          -4.0f*(float)h/(float)w, 
                           4.0f*(float)h/(float)w, 
                         -10.0f, 10.0f);
        } else {
            myGL.glOrtho (-4.0f*(float)w/(float)h, 
                           4.0f*(float)w/(float)h, 
                          -4.0f,  4.0f,
                         -10.0f, 10.0f);
        }
        myGL.glMatrixMode (GL.GL_MODELVIEW);
    }

    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 ();
    }

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

    public void paint (Graphics g) {
	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 auxIdleFunc(display)
	display ();
    }

}