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 bezcurve 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);

    private static final float ctrlpoints [][] = {
    			{-4.0f, -4.0f, 0.0f},
			{-2.0f,  4.0f, 0.0f},
			{ 2.0f, -4.0f, 0.0f},
			{ 4.0f,  4.0f, 0.0f}};

    private void myinit () {
	myGL.glClearColor (0.0f, 0.0f, 0.0f, 1.0f);
	myGL.glMap1f (GL.GL_MAP1_VERTEX_3, 0.0f, 1.0f, 3, 4, ctrlpoints);
	myGL.glEnable (GL.GL_MAP1_VERTEX_3);
	myGL.glShadeModel (GL.GL_FLAT);
    }

    private void display () {
    	int i;

	myGL.glClear (GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
	myGL.glColor3f (1.0f, 1.0f, 1.0f);
	myGL.glBegin (GL.GL_LINE_STRIP);
	    for (i = 0; i <= 30; i++) {
	    	myGL.glEvalCoord1f ((float)i/30.0f);
	    }
	myGL.glEnd ();
	/* The following code displays the control points as dots. */
	myGL.glPointSize (5.0f);
	myGL.glColor3f (1.0f, 1.0f, 0.0f);
	myGL.glBegin (GL.GL_POINTS);
	    for (i = 0; i < 4; i++) {
	    	myGL.glVertex3fv (ctrlpoints[i]);
	    }
	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 ();
	if (w <= h) {
	    myGL.glOrtho (-5.0f, 5.0f,
	    		  -5.0f *(float)h/(float)w,
			   5.0f *(float)h/(float)w,
			  -5.0f, 5.0f);
	} else {
	    myGL.glOrtho (-5.0f *(float)w/(float)h,
	    		   5.0f *(float)w/(float)h,
			  -5.0f, 5.0f,
			  -5.0f, 5.0f);
	}
        myGL.glMatrixMode (GL.GL_MODELVIEW);
        myGL.glLoadIdentity ();
    }

    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 ();
    }

}