Can someone tell me how to change obj file in the applet

Question

Thanks in advance.
I have try to use the ObjLoad example in the java3d demo to
change the obj file.But I fail to do this.
I had use twe applet,one to change name,and then refresh the other
frame to try to relod th obj file. but
java.lang.NullPointerException
at ObjLoad.init(ObjLoad.java:150)
at sun.applet.AppletPanel.run(AppletPanel.java:348)
at java.lang.Thread.run(Thread.java:536)
can you help me?
thanks

Answer 1

Sun's Java3d FlyThrough Demo & Java3d Scenegraph Editor
allow you to load mutiple 3d files (sequencially) including VRML
files with the Sun VRML Loaders at run-time
-- and the Java Source Code is free --- ( see below )
First, try a Web Demo of the "Appearance Explorer" :
"Appearance Explorer" Java3d Web Applet, Loads multiple ".obj"
http://web3dbooks.com/java3d/jumpstart/AppearanceExplorer.html
- click on "Data"
- click on "Obj File: Galleon" -- or -- "Obj File: Beethoven"
- rinse, rather, repeat.
|
http://web3dbooks.com/java3d/jumpstart/Java3DExplorer.html
http://web3dbooks.com/java3d/jumpstart/J3DJumpStart.zip
| ^-- free source code
|
http://www.frontiernet.net/~imaging/games_with_java3d.html
| Sun's Java3d Scenegraph Editor showing a Nasa VRML model
| --------------------------------------------------------
|
| uses the Sun VRML Loaders, source code available and is free.
|
| [ at this url: ] http://java3d.netbeans.org/j3deditor_intro.html
|
http://www.frontiernet.net/~imaging/terrain_rendering.html#Scenegraph_Editor
http://www.frontiernet.net/~imaging/terrain_rendering.html
Selman wrote a Java3d book that was well received
and has a Swingtest.java applet and application that
allows you to load objects dynamically,
ie. "change" the viewed object when it is running by
allowing the user to select "sphere" or "cube" from
menu lists ( in this case it's not just displaying
Jav3d primative objects, but it has the core functionality
of deleteing and adding nodes in the scene graph that you
are seeking, and at that point the rest is left as
exercise to the student. The ObjLoad.java in Sun's Demos
directory has the code to load ".obj" files, so you have
all the tools you need.
| Picking of VRML objects with your mouse is demonstrated
| in a new book, Java 3D Programming, by Daniel Selman
| ( shown on the left ).
|
| The source code is avaible for free.
|
| [ here: ] http://www.manning.com/selman/selman_source.zip
|
| This new book uses the old, reliable Sun VRML Loaders for Java3d.
|
| The program reads a 3d scene as a simple VRML text file,
| and displays the Java3d Scene Graph ( which is interactive,
| you can expand and collapse the branches of the scenegraph
| and examine the contents of the nodes ), it renders the
| 3d scene, and when you click on an object it tells you
| what you clicked on.
|
| You can see ( and download ) the Java Source code of
| the operative file: VrmlPickingTest.java
|
| The publisher's site has more informatation on the book.
|
http://www.frontiernet.net/~imaging/games_with_java3d.html
http://www.frontiernet.net/~imaging/sourcecode/VrmlPickingTest.java
The Prentice-Hall books by Aaron Walsh are false & fraudulent
in their claims to present the most current methods, as a part
of the "Couch-Beiter Flame War" and fraud involving Sandy Ressler
at the NIST. Prentice-Hall, Yumetech.com and Aaron Walsh have
misrepresented and disparaged the old & reliable Sun VRML Loaders
in favor of the "new" Yumetech.com Loader, and the web demo above
__ DOES NOT __ load Web3d.org's __ VRML __ files, only the less
capable ".obj" files ... so the "Web3d" series of books from Prentice-Hall
does not show the loading of ___ Web3d.org 's ___ VRML __ files
because Sun's VRML Loaders were the best ones, and the Yumetech.com
folks didn't want anyone using those, and started the "Couch-Beitler Flame War"
to disparage, falsely & fraudulently misrepresent the facts and knowingly
published false and misleading "disinformation" in the
unreliable Prentice-Hall / Pearson Ed books, harming our community.
The Sun VRML Loaders are used by __ Nasa, __
the NSF supported Virtual Chemistry Lab ( "Lab3d" ),
me, and others simply choosing the "what works best",
and by people using Sun's Java3d FlyThrough & Java Scenegraph Editor.
symsan wrote:
|
| Thanks a lot,but can you give some code
| about to change the Obj file or vrml file,
| when the user in the browser to choose
| the file or input to the textField ?
|
I misunderstood the original question ( it was too terse ).
I interpreted the question has how to change the loaded
objects --- between successive runs of the program ---
and not as you intended -- dynamicall while running
the program program without quiting & restarting.
In a "Java3d" forum I'm not going to wander into
how basic ( non-Java3d) 2d commonents such as TextFields
are programmed.
The original Vrml97Player.java file that came with
Sun VRML Loaders also implemented the functionality
of loading mulitiple files ( sequentically during one run )
and I have worked with that and similar things with
the Shout3d.com engine and my own 3d Java engines.
-- Paul, Java Developer & Web Animator
Imaging the Imagined: Modeling with Math & a Keyboard