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 smooth 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 myinit () {
	myGL.glShadeModel (GL.GL_SMOOTH); /* GL_SMOOTH is the default */
    }

    private void triangle () {
    	myGL.glBegin (GL.GL_TRIANGLES);
	    myGL.glColor3f (1.0f, 0.0f, 0.0f);
	    myGL.glVertex2f (5.0f, 5.0f);
	    myGL.glColor3f (0.0f, 1.0f, 0.0f);
	    myGL.glVertex2f (25.0f, 5.0f);
	    myGL.glColor3f (0.0f, 0.0f, 1.0f);
	    myGL.glVertex2f (5.0f, 25.0f);
	myGL.glEnd ();
    }

    private void display () {
	myGL.glClear (GL.GL_COLOR_BUFFER_BIT);
	triangle ();
	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) {
            myGLU.gluOrtho2D (0.0, 30.0, 0.0, 30.0 * (float)h /(float)w);
        } else {
            myGLU.gluOrtho2D (0.0, 30.0 * (float)w/(float)h, 0.0, 30.0);
        }
        myGL.glMatrixMode (GL.GL_MODELVIEW);
    }

    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 ();
    }

}