Hi,
>When do you expect a bug-fix version of 1.2 Beta for DirectX ?
>There are some bugs, i.e.
>4309059 background geometry appears very close to the camera vs 1.1.3
>(....in 1.2, too !!!)
>4328532 Textures for the bottom of cones and cylinders are upside-down
>4332793 View transform & object transform not synchronized in a single
>behavior
>which make working really hurting :-(
>
The above bugs is not specific to DirectX version,
it occurs in OpenGL version also.
The first two bugs will be fixed in next
Java3D v1.2.1 beta release.
The last one is not a bug, please see the following
message.
Thanks.
- Kelvin
-----------------
Java 3D Team
Sun Microsystems Inc.
> ------------- Begin Forwarded Message -------------
>
> Date: Mon, 26 Jun 2000 18:32:08 -0700 (PDT)
> From: Kelvin Chung <tlchung@ha3mpk>
> Subject: Re: View and Scene synchronization bug
> To: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED]
> Cc: www.manning.com/barrilleaux
> Mime-Version: 1.0
>
> Hi,
>
> To better understand this problem, let's take a look at
> the simply version has only one behavior to both rotate
> the cube and modify the camera viewpoint so that
> we expect the cube appear stationary. This example is modify
> from HelloUniverse example.
>
> If we write the behavior in this way :
>
> public void processStimulus(Enumeration criteria) {
> Modify Camera View point using the object transform
> Modify Object transform as in RotationInterpolator
> }
>
> Using J3D v1.2 we will see the cube jitters
> (more serious under windows than solaris).
>
> However if we write the behavior in this way :
>
>
> public void processStimulus(Enumeration criteria) {
> Modify Object transform as in RotationInterpolator
> Modify Camera View point using object transform
>
> }
>
> There is NO jitter at all under both platform.
>
> In fact you will also see the cube jitter
> when using J3D 1.1.3 under windows.
>
> This is not a bug. Here is the explanation :
>
> -------------------
> The object transform that that camera view point get is
> ONE frame before what RotationInterpolator is about to
> be set. If the timing of frame is equal between every
> successive processStimulus() invocation. Then the
> different between the alpha values of rotation interpolator
> get from one frame to another should be the same and you
> will always see the same offset from the camera to the cube.
> i.e. the cube appear did not move at all without any jitter.
>
> However, in reality the interval processStimulus() is invoked
> is not exactly the same from frame to frame. It all depends
> on the OS scheduling. So the offset of view from camera to
> the cube may varies from frame to frame and you will see the
> cube jitters all the time. This phenomenon is more obvious
> under windows than sparc solaris - the later has finer time
> resolution and better scheduling. Thats why you may
> see the program run fine under solaris but jitter under windows.
>
> To solve the problem, the user behavior has to ganrantee
> that the transform set by the camera and the cube are the
> in sync by putting them in a single behaviors and same
> transform is apply to interpolators first if it is need
> to compute the camera viewpoint.
>
> --------------
>
> In the two example programs given (attach in the email),
> there are two behaviors :
>
> (A) Modify the object transformation matrix using some
> kinds of Interpolator.
> (B) Read back the transform matrix (which is modify by A)
> and use it to transform camea under View
>
> If behavior A is always schedule to run before behavior B
> in Java3D, you will not see any jitter. However there is
> no gaurantee for the order of behaviors execute under Java3D.
> So you may see (A) run before (B) or (B) run befores (A)
> or (A)&(B) may run in parallel if there are two CPU in your system.
>
> Currently there is no API to gaurantee order of behaviors running
> in Java3D. The solution is to make sure if camera viewpoint
> transformation matrix depends on result of other behaviors,
> we should put them in a single behavior to sync both
> transform.
>
> Attach is a program modify from the original CameraFollow
> behavior to see how it works. Running this program in
> both windows & solaris and you wouldn't see the jitter.
>
> Thanks.
>
> - Kelvin
> -----------------
> Java 3D Team
> Sun Microsystems Inc.
import javax.vecmath.*;
> import javax.media.j3d.*;
> import java.util.*;
>
> /*
> This class is a behavior that is meant to be used for creating
> a "following" camera effect.
> Every update (elapsed frame 0) it copies and store the targets matrix
> in a buffer, then sets it own tranform from the end of the buffer.
> The effect is a view chasing or following of the target transform.
> However, if the buffer size is set to 1, then the offset is the only
> difference between the target transform and the output transfrom
> */
>
> public class CameraFollow extends Behavior
> {
> WakeupCondition wake = new WakeupOnElapsedFrames(0);
> public TransformGroup targetTG = null;
> public TransformGroup cameraTG = null;
> Transform3D tr3d = new Transform3D();
> Matrix4d offsetMat = new Matrix4d();
> final int MAX_BUFFER = 1;
> Matrix4d[] mat = new Matrix4d[MAX_BUFFER];
>
> int queueCount = 0;
> int lagCount = 0;
> Alpha alpha;
> Transform3D axis = new Transform3D();
> Transform3D axisInverse = new Transform3D();
> TransformGroup target;
> float minimumAngle ;
> float maximumAngle ;
>
> Transform3D rotation = new Transform3D();
> Transform3D temp = new Transform3D();
>
> public CameraFollow(TransformGroup objTrans) {
> super();
> target = objTrans;
> alpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
> 0, 0,
> 4000, 0, 0,
> 0, 0, 0);
> axisInverse.invert(axis);
> minimumAngle = 0.0f;
> maximumAngle = (float) (Math.PI*2.0f);
>
> }
>
> public void initialize()
> {
> for ( int i = 0; i<MAX_BUFFER ; i++ )
> {
> mat[i] = new Matrix4d();
> mat[i].setIdentity();
> }
> offsetMat.setIdentity();
> offsetMat.setTranslation( new Vector3d( 0.0f, 0.5f, 3.0f ) );
> wakeupOn(wake);
>
> }
>
> public void processStimulus(Enumeration criteria)
> {
>
> // Perform the function of RotationInterpolator
> if (alpha != null) {
> float value = this.alpha.value();
> double val = (1.0-value)*minimumAngle + value*maximumAngle;
> /* construct a Transform3D from: axis * rotation * axisInverse
*/
> rotation.rotY(val);
>
> temp.mul(axis, rotation);
> temp.mul(temp, axisInverse);
>
> target.setTransform(temp);
> }
>
>
>
> // Transform the Camera view point
> if ( cameraTG != null )
> {
> if ( targetTG != null )
> {
> targetTG.getTransform(tr3d);
>
> // Copy the targets matrix to the buffer
> tr3d.get(mat[queueCount]);
>
> //lagCount = queueCount + 1;
> //if ( lagCount >= MAX_BUFFER )
> // lagCount = 0;
>
> // Multiple in the view offset
> mat[lagCount].mul( offsetMat );
>
> tr3d.set(mat[lagCount]);
>
> // Finally, set the transfrom above the ViewPlatform
> cameraTG.setTransform( tr3d );
>
> //queueCount++;
> //if ( queueCount >= MAX_BUFFER )
> // queueCount = 0;
> }
> }
>
> wakeupOn(wake);
> }
> }
>
> ----------------------------------------------------------------------
> /*
> * @(#)HelloUniverse.java 1.47 99/09/15 13:36:59
> *
> * Copyright (c) 1996-1999 Sun Microsystems, Inc. All Rights Reserved.
> *
> * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
> * modify and redistribute this software in source and binary code form,
> * provided that i) this copyright notice and license appear on all copies of
> * the software; and ii) Licensee does not utilize the software in a manner
> * which is disparaging to Sun.
> *
> * This software is provided "AS IS," without a warranty of any kind. ALL
> * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
ANY
> * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
> * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
> * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
> * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
ITS
> * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
> * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
> * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
> * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
> * POSSIBILITY OF SUCH DAMAGES.
> *
> * This software is not designed or intended for use in on-line control of
> * aircraft, air traffic, aircraft navigation or aircraft communications; or
in
> * the design, construction, operation or maintenance of any nuclear
> * facility. Licensee represents and warrants that it will not use or
> * redistribute the Software for such purposes.
> */
>
> import java.applet.Applet;
> import java.awt.BorderLayout;
> import java.awt.event.*;
> import java.awt.GraphicsConfiguration;
> import com.sun.j3d.utils.applet.MainFrame;
> import com.sun.j3d.utils.geometry.ColorCube;
> import com.sun.j3d.utils.universe.*;
> import javax.media.j3d.*;
> import javax.vecmath.*;
>
> public class HelloUniverse extends Applet {
> CameraFollow cfb;
>
> public BranchGroup createSceneGraph() {
> // Create the root of the branch graph
> BranchGroup objRoot = new BranchGroup();
>
> // Create the transform group node and initialize it to the
> // identity. Enable the TRANSFORM_WRITE capability so that
> // our behavior code can modify it at runtime. Add it to the
> // root of the subgraph.
> TransformGroup objTrans = new TransformGroup();
> objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
> objRoot.addChild(objTrans);
> objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
>
> // Create a simple shape leaf node, add it to the scene graph.
> objTrans.addChild(new ColorCube(0.4));
>
> BoundingSphere bounds =
> new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
>
> // Create a new Behavior object that will perform the desired
> // operation on the specified transform object and add it into
> // the scene graph.
> /*
> Transform3D yAxis = new Transform3D();
> Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
> 0, 0,
> 4000, 0, 0,
> 0, 0, 0);
>
> RotationInterpolator rotator =
> new RotationInterpolator(rotationAlpha, objTrans, yAxis,
> 0.0f, (float) Math.PI*2.0f);
> rotator.setSchedulingBounds(bounds);
> objTrans.addChild(rotator);
> */
> // added by SFK
> cfb = new CameraFollow(objTrans);
> cfb.targetTG = objTrans;
> // cfb.cameraTG = cameraTG;
> cfb.setSchedulingBounds(bounds);
> objTrans.addChild(cfb);
> // end added by SFK
>
> // Have Java 3D perform optimizations on this scene graph.
> objRoot.compile();
>
> return objRoot;
> }
>
> public HelloUniverse() {
> setLayout(new BorderLayout());
> GraphicsConfiguration config =
> SimpleUniverse.getPreferredConfiguration();
>
> Canvas3D c = new Canvas3D(config);
> add("Center", c);
>
> // Create a simple scene and attach it to the virtual universe
> BranchGroup scene = createSceneGraph();
> SimpleUniverse u = new SimpleUniverse(c);
>
> // added by SFK
> cfb.cameraTG =
u.getViewingPlatform().getMultiTransformGroup().getTransformGroup(0);
> // end added by SFK
>
> // This will move the ViewPlatform back a bit so the
> // objects in the scene can be viewed.
> u.getViewingPlatform().setNominalViewingTransform();
>
> u.addBranchGraph(scene);
> }
>
> //
> // The following allows HelloUniverse to be run as an application
> // as well as an applet
> //
> public static void main(String[] args) {
> new MainFrame(new HelloUniverse(), 256, 256);
> }
> }
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff JAVA3D-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
