How do you add a ViewingPlatform to a Transform Group, and make it move?

Question

Hello,
I am reasonably new to Java3d and have been looking around the forum about how to add a ViewingPlatform to a transform group. I did find several posts and they did help to get me to put a ViewingPlatform into a transform group, but now I have a problem of not being bale to move it:
The public void actionPerformed(ActionEvent e ) is where the code changes the xloc and zloc variables and make the transform group move. However I get an error when I try to add the Camera to this transform group which is moved.
Thanks in Advance.
Mahen.net

Answer 1

My code is:
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.WindowAdapter;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.geometry.Sphere;
import javax.swing.Timer;
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.loaders.objectfile.ObjectFile;
import com.sun.j3d.loaders.*;
public class BouncingBall extends Applet implements ActionListener, KeyListener {
     private Button go = new Button("Go");
     private TransformGroup objTrans;
     private TransformGroup vpTrans;
     private Transform3D trans = new Transform3D();
     private Transform3D trans2 = new Transform3D();
     private Timer timer;
     private float xloc=0.0f;
     private float zloc=0.0f;
     public BranchGroup createSceneGraph(SimpleUniverse su) {
        BranchGroup objRoot = new BranchGroup();
        // lanscape
        TransformGroup tg = new TransformGroup();
        TransformGroup tg1 = new TransformGroup();
        TransformGroup tg2 = new TransformGroup();
        TransformGroup tg3 = new TransformGroup();
        TransformGroup tg4 = new TransformGroup();
        tg.addChild(tg1);
        tg.addChild(tg2);
        tg.addChild(tg3);
        tg.addChild(tg4);
        Transform3D transform1 = new Transform3D();
        Transform3D transform2 = new Transform3D();
        Transform3D transform3 = new Transform3D();
        Transform3D transform4 = new Transform3D();
        transform1.setTranslation(new Vector3f(2.0f,0.0f,0.0f));
        transform2.setTranslation(new Vector3f(-1.5f,0.0f,0.0f));
        transform3.setTranslation(new Vector3f(1.0f,1.0f,-2.0f));
        transform4.setTranslation(new Vector3f(-2.0f,-1.0f,1.0f));
        tg1.setTransform(transform1);
        tg2.setTransform(transform2);
        tg3.setTransform(transform3);
        tg4.setTransform(transform4);
        tg1.addChild(new ColorCube(0.4));
        tg2.addChild(new ColorCube(0.4));
        tg3.addChild(new ColorCube(0.4));
        tg4.addChild(new ColorCube(0.4));
        objRoot.addChild(tg);
        //character
        objTrans = new TransformGroup();
        objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        objRoot.addChild(objTrans);
        objTrans = new TransformGroup();
        objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        Transform3D pos1 = new Transform3D();
        pos1.setTranslation(new Vector3f(0.0f,-0.5f,0.0f));
        objTrans.setTransform(pos1);
        // loading object
        try
               Scene s = null;
               ObjectFile f = new ObjectFile ();
                    f.setFlags (ObjectFile.RESIZE | ObjectFile.TRIANGULATE | ObjectFile.STRIPIFY);
               String s1 = "gun.obj";
               s = f.load (s1);
               objTrans.addChild (s.getSceneGroup ());
          catch (java.io.FileNotFoundException ex){
        objRoot.addChild(objTrans);
        // lighting
        BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
        Color3f light1Color = new Color3f(1.8f, 0.1f, 0.1f);
        Vector3f light1Direction = new Vector3f(4.0f, -7.0f, -12.0f);
        DirectionalLight light1  = new DirectionalLight(light1Color, light1Direction);
        light1.setInfluencingBounds(bounds);
        objRoot.addChild(light1);
        Color3f ambientColor = new Color3f(1.0f, 1.0f, 1.0f);
        //camera
        Vector3f translate = new Vector3f();
        TransformGroup vpTrans = new TransformGroup();         
        vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        vpTrans = su.getViewingPlatform().getViewPlatformTransform();
        vpTrans = new TransformGroup();
        vpTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        Transform3D T3D = new Transform3D();     
        T3D.setTranslation(translate);
        translate.set( 0.0f, 0.0f, 3.0f);
        vpTrans.setTransform(T3D);
        return objRoot;
     }