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

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

public class robot extends Applet
		   implements ComponentListener, KeyListener {
    // 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 int shoulder = 0, elbow = 0;

    private void elbowAdd () { elbow = (elbow + 5) % 360; }
    private void elbowSubtract () { elbow = (elbow - 5) % 360; }
    private void shoulderAdd () { shoulder = (shoulder + 5) % 360; }
    private void shoulderSubtract () { shoulder = (shoulder - 5) % 360; }

    public void keyTyped (KeyEvent e) {}
    public void keyReleased (KeyEvent e) {}

    public void keyPressed (KeyEvent e) {
        int keyCode = e.getKeyCode();

        if (keyCode == KeyEvent.VK_LEFT) {
            shoulderSubtract ();
            display ();
            repaint ();
        } else if (keyCode == KeyEvent.VK_RIGHT) {
            shoulderAdd ();
            display ();
            repaint ();
        } else if (keyCode == KeyEvent.VK_UP) {
            elbowAdd ();
            display ();
            repaint ();
        } else if (keyCode == KeyEvent.VK_DOWN) {
            elbowSubtract ();
            display ();
            repaint ();
        }
        e.consume ();
    }

    private void display () {
	myGL.glClear (GL.GL_COLOR_BUFFER_BIT);
	myGL.glColor3f (1.0f, 1.0f, 1.0f);
	myGL.glPushMatrix ();

	    myGL.glTranslatef (-1.0f, 0.0f, 0.0f);
	    myGL.glRotatef ((float)shoulder, 0.0f, 0.0f, 1.0f);
	    myGL.glTranslatef (1.0f, 0.0f, 0.0f);
	    myAUX.auxWireBox (2.0, 0.4, 1.0);	/* shoulder */

	    myGL.glTranslatef (1.0f, 0.0f, 0.0f);
	    myGL.glRotatef ((float)elbow, 0.0f, 0.0f, 1.0f);
	    myGL.glTranslatef (1.0f, 0.0f, 0.0f);
	    myAUX.auxWireBox (2.0, 0.4, 1.0);	/* elbow */

	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, (double)w/(double)h, 1.0, 20.0);
	myGL.glMatrixMode (GL.GL_MODELVIEW);
	myGL.glLoadIdentity ();
	myGL.glTranslatef (0.0f, 0.0f, -5.0f);
    }

    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, 400, 400);
	myAUX.auxInitWindow (this);
	myinit ();

	// as call auxKeyFunc()
        addKeyListener(this);

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

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

}