Hi Travis,
On Sun, 24 Jan 1999, Travis Bryson wrote:
>
> Hi Helmuth,
>
> Your application sounds very interesting.
>
> Do you have a reproducible test case that can be run in a standard flat
> screen environment?
It would take some work, but I could make it work without the glove. It
works on a flat panel now.
>
> I am not sure what you mean by this. You should never call
> processStimulus from your own code. However, maybe you were trying to
> do something unusual to work around the bug.
>
This is the code I am using to attach (and unattach) the object to (and
from) the hand: (sorry it doesn't look very elegant)
I call "attachToHand" when the object is colliding with the hand and the
user is doing a "grasp" gesture with the glove. And I call
"unattachToHand" when the user does a "release" gesture.
Most of the code is copied from the SUN examples, specifically
"TickTockCollision".
The problem is that when the user "releases" the object, and I attach it
to its original position, sometimes the object remains "highlighted", the
collision detector waiting for a "WakeupOnCollisionExit", which should
have taken place as soon as it was not colliding with the virtual hand.
Any advice is highly appreciated!
Helmuth
================ start of code ========================
import javax.media.j3d.*;
import javax.vecmath.*;
import java.util.*;
/**
* Creates a graspable object
* @author: Helmuth Trefftz
* January 1999.
*
*/
public class GraspableObject {
public boolean colliding = false;
public boolean grasped = false;
public Group myGroup;
public BranchGroup myBranchGroup;
public BranchGroup myRoot;
public CollisionDetector cd;
public Shape3D shape;
public TransformGroup objTrans;
public boolean first_time = true;
private Hand hand;
public GraspableObject(Hand theHand) {
hand = theHand;
}
public void attachToHand() {
int myIndex = 0;
int nc = myRoot.numChildren();
for (int i = 0; i < nc; i++) {
if (myRoot.getChild(i) == myBranchGroup) {
myIndex = i;
}
}
System.out.println("My Index: " + myIndex);
myRoot.removeChild(myIndex);
hand.handYPR.addChild(myBranchGroup);
grasped = true;
}
public void unAttachToHand() {
int myIndex = 0;
int nc = hand.handYPR.numChildren();
for (int i = 0; i < nc; i++) {
if (hand.handYPR.getChild(i) == myBranchGroup) {
myIndex = i;
}
}
System.out.println("My Index: " + myIndex);
hand.handYPR.removeChild(myIndex);
myRoot.addChild(myBranchGroup);
grasped = false;
}
public Group createBox(double scale, Vector3d pos) {
// Create a transform group node to scale and position the object.
Transform3D t = new Transform3D();
t.set(scale, pos);
objTrans = new TransformGroup(t);
// Create a simple shape leaf node and add it to the scene graph
shape = new Box(1.0, 1.0, 1.0);
objTrans.addChild(shape);
// Create a new ColoringAttributes object for the shape's
// appearance and make it writable at runtime.
Appearance app = shape.getAppearance();
ColoringAttributes ca = new ColoringAttributes();
ca.setColor(0.6f, 0.3f, 0.0f);
app.setCapability(app.ALLOW_COLORING_ATTRIBUTES_WRITE);
app.setColoringAttributes(ca);
addCollisionDetection();
return objTrans;
}
public void addCollisionDetection() {
// Create a new Behavior object that will perform the collision
// detection on the specified object, and add it into
// the scene graph.
cd = new CollisionDetector(shape,this);
BoundingSphere bounds =
new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
cd.setSchedulingBounds(bounds);
// Add the behavior to the scene graph
objTrans.addChild(cd);
}
}
================ end of code ========================
>
> Travis Bryson
>
> Sun Microsystems
>
>
> > X-Authentication-Warning: multimodal1.rutgers.edu: trefftz owned process doing
> -bs
> > Date: Sun, 24 Jan 1999 19:30:56 -0500 (EST)
> > From: Helmuth Trefftz <[EMAIL PROTECTED]>
> > To: [EMAIL PROTECTED]
> > Subject: [java3d] Collision Detection
> > MIME-Version: 1.0
> >
> > Hi,
> >
> > I am building a Java3D application in which I grasp and release objects
> > with a VR glove. When I detect a collision between the object and the
> > virtual hand (using Java3D collision detection) I attach the object to the
> > palm of the hand. So far so good.
> >
> > But when I release the object from the palm, and attach it to its original
> > position, the "WakeupOnCollisionExit" is never produced and the object
> > remains as if colliding with the hand (obviously wrong, since it is now
> > far away from the hand).
> >
> > I need to force Java to produce a "WakeupOnCollisionExit" when I release
> > the object, but have not found a way to do it. Calling "processStimulus"
> > with an empty enumeration does not work. Adding a new "collisionDetector"
> > (like in the TickTockCollision example) does not work either.
> >
> > What can I do?
> >
> > -------------------------------------------------------
> > Helmuth Trefftz
> > Rutgers University
> > e-mail: [EMAIL PROTECTED]
> > tel: (732) 445 0561 fax: (732) 445 4775
> > -------------------------------------------------------
> >
> > =====================================================================
> > To subscribe/unsubscribe, send mail to [EMAIL PROTECTED]
> > Java 3D Home Page: http://java.sun.com/products/java-media/3D/
>
>
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