How to mouserotate center on specific point?

Question

Thanks in advance.
Suppose I have a QuadArray (make it simple, a cube with vertex (0,0,0),(1,0,0),(1,1,0),(0,1,0),(0,0,-1),(1,0,-1),(1,1,-1),(0,1,-1)), how can I make mouserotate on its center (in this case, (0.5,0.5,-0.5)) without rewritting the vertex of the QuadArray?
I translate it to the view center but the rotation point seems still set on the front left bottom of the cube. Please help.

Answer 1

here is the class i wrote to move around a point (and looking at the point)
hope this will help,
Franck
( you can see the result at : http://membres.lycos.fr/franckcalzada/Billard3D/Pool.html )
package com.caza.behaviors;
import java.awt.AWTEvent;
import java.awt.event.MouseEvent;
import java.util.Enumeration;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import javax.media.j3d.WakeupCriterion;
import javax.media.j3d.WakeupOnAWTEvent;
import javax.vecmath.Vector3f;
import com.caza.billard3D.Ball;
import com.caza.billard3D.Pool;
import com.sun.j3d.utils.behaviors.mouse.MouseBehavior;
import com.sun.j3d.utils.behaviors.mouse.MouseBehaviorCallback;
public class TableRotateBehavior extends MouseBehavior {
     private static final int MIN_YAW = 10;
     private static final int MAX_YAW = 120;
     private static final float MIN_SCALE = 3.0f;
     private static final float MAX_SCALE = 170.0f;
     private TransformGroup mainTransformGroup;
     private Ball cueBall;
     private float m_roll = 0;
     private float m_pitch = 0;
     private float m_yaw = 0;
     private float m_focal = 100;
     private boolean viewFromWhiteBall;
     private MouseBehaviorCallback callback = null;
     * Creates a rotate behavior given the transform group.
     * @param transformGroup The transformGroup to operate on.
     public TableRotateBehavior(TransformGroup mainTransformGroup, Ball cueBall, boolean viewFromWhiteBall) {
          this();
          this.mainTransformGroup = mainTransformGroup;
          this.cueBall = cueBall;
          this.viewFromWhiteBall = viewFromWhiteBall;
     * Creates a default mouse rotate behavior.
     private TableRotateBehavior() {
          super(0);
     public void initialize() {
          super.initialize();
          m_roll = 0;
          m_pitch = 0;
          m_yaw = 45;
          m_focal = 100;
     public void setFocal(float focal) {
          m_focal = focal;
     public float getFocal() {
          return m_focal;
     public float getPitch() {
          return m_pitch;
     public void setupCallback( MouseBehaviorCallback callback ) {
          this.callback = callback;
     public void processStimulus(Enumeration criteria) {
          WakeupCriterion wakeup;
          AWTEvent[] event;
          int id;
          while (criteria.hasMoreElements()) {
               wakeup = (WakeupCriterion) criteria.nextElement();
               if (wakeup instanceof WakeupOnAWTEvent) {
                    event = ((WakeupOnAWTEvent) wakeup).getAWTEvent();
                    for (int i = 0; i < event.length; i++) {
                         processMouseEvent((MouseEvent) event);
                         if (((buttonPress) && ((flags & MANUAL_WAKEUP) == 0))
                              || ((wakeUp) && ((flags & MANUAL_WAKEUP) != 0))) {
                              id = event[i].getID();
                              if ((id == MouseEvent.MOUSE_DRAGGED)
//                                   && !((MouseEvent) event[i]).isMetaDown()
                                   && !((MouseEvent) event[i]).isAltDown()
//                                   && ((MouseEvent) event[i]).isControlDown()
                                   handleMouseMove(((MouseEvent) event[i]));
                              else if (
                                   (id == MouseEvent.MOUSE_DRAGGED) &&
                                   ((MouseEvent) event[i]).isAltDown()
//                                   !((MouseEvent) event[i]).isMetaDown()
//                                   ((MouseEvent) event[i]).isControlDown()
                                   handleMouseScale(((MouseEvent) event[i]));                              
                              else if (id == MouseEvent.MOUSE_PRESSED) {
                                   x_last = ((MouseEvent) event[i]).getX();
                                   y_last = ((MouseEvent) event[i]).getY();
                              if (callback!=null) {
                                   callback.transformChanged( MouseBehaviorCallback.ROTATE, null);
          wakeupOn(mouseCriterion);
     private void handleMouseScale(MouseEvent mouseEvent) {
          float dy;
          y = mouseEvent.getY();
          if (!viewFromWhiteBall) {
               dy = y - y_last;
               // ZOOM
               m_focal += dy;
               if (m_focal < MIN_SCALE) {
                    m_focal = MIN_SCALE;
               if (m_focal > MAX_SCALE) {
                    m_focal = MAX_SCALE;
               // test if look above the floor
               if (Math.sin(Math.toRadians(m_yaw + dy + 90))*m_focal < -18.0) {
                    m_focal -= dy;
          else {
               m_focal = 3.0f;
          CameraByTransform(
               0, 0, 0
          y_last = y;
     private void handleMouseMove(MouseEvent mouseEvent) {
          float dx, dy;
          x = mouseEvent.getX();
          y = mouseEvent.getY();
          dx = (x - x_last) / 2.0f;
          if (!viewFromWhiteBall) {
               dy = y - y_last;
               if (m_yaw + dy <= MIN_YAW) {
                    m_yaw = MIN_YAW;
                    dy = 0;          
               if (m_yaw + dy >= MAX_YAW) {
                    m_yaw = MAX_YAW;
                    dy = 0;          
               // test if look above the floor
               if (Math.sin(Math.toRadians(m_yaw + dy + 90))*m_focal < -18.0) {
                    dy = 0;
          else {
               dy = 0;          
               m_yaw = 84;     
          if (!reset) {
               CameraByTransform(
                    dy, -dx, 0
          } else {
               reset = false;
          x_last = x;
          y_last = y;
     private Transform3D setTransform(
          float pitch,
          float yaw,
          float roll
          //method to rotate then position
          Transform3D ret = new Transform3D(); //return transform
          Transform3D xrot = new Transform3D();
          Transform3D yrot = new Transform3D();
          Transform3D zrot = new Transform3D();
          if (Pool.instance().gamePlay.isHelping()) {
               ret.set(cueBall.getPreviousPosition());
          else {
               ret.set(cueBall.getPosition());
          //roll pitch yaw rotations by Degrees
          yrot.rotY(roll / 360 * (2 * Math.PI));
          xrot.rotX(pitch / 360 * (2 * Math.PI));
          zrot.rotZ(yaw / 360 * (2 * Math.PI));
          //multiply return values by rotation
          //(order of multiplication is important dependent on coordinate system being used)
          ret.mul(zrot);
          ret.mul(xrot);
          ret.mul(yrot);
          return ret;
     private void CameraByTransform(
          float yaw,
          float pitch,
          float roll
          m_yaw = m_yaw + yaw;
          m_pitch = m_pitch + pitch;
          m_roll = m_roll + roll;
          Transform3D rot1 = setTransform(m_yaw, m_pitch, m_roll);
          Transform3D pos = new Transform3D();
          pos.setTranslation(new Vector3f(
               0.0f,
               0.0f,
               m_focal
          rot1.mul(pos);
//          System.out.println("SelmanKeyBehavior.rot1 = " + rot1);
          mainTransformGroup.setTransform(rot1);