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 clip 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 void display () {
    	double eqn [] = {0.0, 1.0, 0.0, 0.0};	/* y < 0 */
	double eqn2 [] = {1.0, 0.0, 0.0, 0.0};	/* x < 0 */

	myGL.glClear (GL.GL_COLOR_BUFFER_BIT);

	myGL.glColor3f (1.0f, 1.0f, 1.0f);
	myGL.glPushMatrix ();
	myGL.glTranslatef (0.0f, 0.0f, -5.0f);

	myGL.glClipPlane (GL.GL_CLIP_PLANE0, eqn);
	myGL.glEnable (GL.GL_CLIP_PLANE0);
	myGL.glClipPlane (GL.GL_CLIP_PLANE1, eqn2);
	myGL.glEnable (GL.GL_CLIP_PLANE1);

	myGL.glRotatef (90.0f, 1.0f, 0.0f, 0.0f);
	myAUX.auxWireSphere (1.0);
	myGL.glPopMatrix ();
	myGL.glFlush ();
    }

    private void myinit () {
	myGL.glShadeModel (GL.GL_FLAT);
    }

    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, (float)w/(float)h, 1.0, 20.0);
        myGL.glMatrixMode (GL.GL_MODELVIEW);
    }

    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 ();
    }

}