Need jPCT Guidance

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import java.io.File;

import javax.swing.JApplet;

import com.threed.jpct.Camera;
import com.threed.jpct.FrameBuffer;
import com.threed.jpct.IRenderer;
import com.threed.jpct.Lights;
import com.threed.jpct.Loader;
import com.threed.jpct.Matrix;
import com.threed.jpct.Object3D;
import com.threed.jpct.SimpleVector;
import com.threed.jpct.World;

public class jPCTTest extends JApplet implements MouseListener, MouseMotionListener
{
    private Object3D redGear;
    private FrameBuffer buffer = null;
    private World world = null;
    private Camera camera = null;
    private int width = 640;
    private int height = 480;
    private float gear_rotation = 0.02f;
    private int prevMouseX, prevMouseY;
    
    // Initialize all components of the applet
    @Override
    public void init()
    {
        // sign the applet up to receive mouse messages:
        addMouseListener( this );
        addMouseMotionListener( this );
        
        world = new World();  // create a new world

        // create a new buffer to render the world on:
        buffer = new FrameBuffer( width, height, FrameBuffer.SAMPLINGMODE_NORMAL );
        buffer.enableRenderer( IRenderer.RENDERER_SOFTWARE );                

        // load some 3D objects and make sure they have the correct orientation:
        redGear = loadMeshFile( "RedGear.3ds" );
        redGear.rotateY( (float)Math.PI / 2.0f );
        redGear.rotateMesh();
        redGear.setRotationMatrix( new Matrix() );
        redGear.setOrigin( new SimpleVector( 0, 0, 0 ) );
        
        // add the objects our world:
        world.addObject( redGear );
        world.buildAllObjects();

        lookAt( redGear );  // make sure the camera is facing towards the object
        letThereBeLight();  // create light sources for the scene
    }

    // Draw the scene
    @Override
    public void paint( Graphics g )
    {
        // rotate the gear:
        redGear.rotateAxis( redGear.getZAxis(), -gear_rotation );
        
        
        buffer.clear();   // erase the previous frame

        // render the world onto the buffer:
        world.renderScene( buffer );
        world.draw( buffer );
        buffer.update();

        buffer.display(g, 0, 0);  // draw the buffer onto the applet frame
        
        repaint( 200, 0, 0, width, height );  // keep the graphics auto-refreshing
    }

    // Load a 3Ds file, and return its Object3D handle
    private Object3D loadMeshFile( String filename )
    {
        Object3D newObject;
        Object3D[] objs = Loader.load3DS( this.getDocumentBase(), "models" + File.separatorChar + filename, 1.0f );

        if( objs.length==1 )
        {
            // The object loaded fine, just need to initialize it
            newObject=objs[0];
            newObject.setCulling( Object3D.CULLING_DISABLED );
            newObject.build();
        }
        else
        {
            // Didn't load anything, or loaded
            //     more than 1 object (not supposed to happen)
            System.out.println( "Unknown file format: " + filename );
            newObject = null;
        }

        return newObject;
    }

    // point the camera toward the given object
    private void lookAt( Object3D obj )
    {
        camera = world.getCamera();  // grab a handle to the camera
        camera.setPosition( 0, 0, 500 );  // set its *relative* position
        camera.lookAt( obj.getTransformedCenter() );  // look toward the object
    }

    // create light sources for the scene
    private void letThereBeLight()
    {
        world.getLights().setOverbrightLighting (
            Lights.OVERBRIGHT_LIGHTING_DISABLED );
        world.getLights().setRGBScale( Lights.RGB_SCALE_2X );

        // Set the overall brightness of the world:
        world.setAmbientLight( 50, 50, 50 );

        // Create a main light-source:
        world.addLight( new SimpleVector( 50, -50, 300 ), 20, 20, 20 );
    }

    // Mouse events:
    public void mouseDragged( MouseEvent e )
    {
        // here we want to rotate the gear based on the mouse dragging
        int x = e.getX();
        int y = e.getY();
        Dimension size = e.getComponent().getSize();

        float thetaY = (float)Math.PI * ( (float)(x-prevMouseX)/(float)size.width );
        float thetaX = (float)Math.PI * ( (float)(prevMouseY-y)/(float)size.height );

        prevMouseX = x;
        prevMouseY = y;
        
        redGear.rotateX( thetaX );
        redGear.rotateY( thetaY );
    }
    public void mousePressed( MouseEvent e )
    {
        // set the "previous" mouse location
        // this prevent the gear from jerking to the new angle
        // whenever mouseDragged gets called
        prevMouseX = e.getX();
        prevMouseY = e.getY();
    }	
    public void mouseReleased( MouseEvent e ){}
    public void mouseEntered( MouseEvent e ) {}
    public void mouseExited( MouseEvent e ) {}
    public void mouseClicked( MouseEvent e ) {}
    public void mouseMoved( MouseEvent e ) {}
}