Introduction to Java 3D

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Introduction to Java 3D

• Winter 2007
• Tao Wang
• Adapted from the Java 3D tutorial and some course
  material

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Outline

• Java 3D Overview
• Introduction to Java 3D API
• Lab

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• Java 3D Overview

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What is Java 3D?

• Java 3D is
• Standard extension to the Java 2 JDK
• An interface for writing programs to display and
  interact with 3D graphics
• Provides a collection of high-level constructs
  for creating and manipulating 3D geometry and
  structures for rendering that geometry
• It is now a community source project developed on
  java.net (https//java3d.dev.java.net/)

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What can Java 3D do?

• Java 3D includes a rich and extensible feature
  set for
• Building shapes
• Composing behaviors
• Interacting with the environment and the user
• Controlling rendering details
• Java 3D enables
• Quick development of complex 3D applications
• Fast and efficient implementation on a variety of
  platforms, from embedded systems to PCs to
  high-end workstations

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Advantage and Disadvantage

• Advantage
• It enables fast Development, so developers do not
  need to manipulate rendering details, they can
  focus on visual contents
• Disadvantage
• It has lower speed than C/OpenGL

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Java 3D Books

• Computer Graphics Using Java 2D and 3D, Y. Daniel
  Liang and Hong Zhang, October 2005
• Java 3D Programming, Daniel Selman, Manning
  Publications, Feb 2002
• Java 3D API Jump-Start, Aaron E. Walsh and Doug
  Gehringer, Prentice Hall, Aug 2001
• Essential Java 3d Fast Developing 3d Graphics
  Applications in Java, Ian Palmer,
  Springer-Verlag, June 2001
• Java 3D (TM) API Specification (2nd Edition),
  Henry Sowizral, Kevin Rushforth, Michael Deering,
  May 2000
• 3D User Interfaces with Java 3D, Jon Barrilleaux,
  Manning Publications, September 2000
• Ready to Run Java 3D, Kirk Brown and Daniel
  Petersen, Wiley Sons, May 1999

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Online Java 3D Resources

• Homepage of Java 3D
• https//java3d.dev.java.net/
• Java 3D API Documentation, Examples and Downloads
• https//java3d.dev.java.net/binary-builds.html
• Java 3D Tutorial (Chapter 0-7, highly
  recommended)
• http//java.sun.com/developer/onlineTraining/java3
  d/index.html
• Java 3D interest group mail archive (searchable)
• http//archives.java.sun.com/archives/java3d-inter
  est.html
• The Java 3D Community Site
• http//www.j3d.org/

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Where to download

• Java 2 SE Downloads
• http//java.sun.com/javase/downloads/index.jsp
• Java 3D
• https//java3d.dev.java.net/binary-builds.html

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Compiling the Examples

• To compile the Java examples, you will need
• 1. The Java 2 SE
• 2. The Java 3D API
• The command
• javac FILENAME.java
• It will compile java source files (.java) to java
  class files (.class)

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Running the Examples

• The command
• java FILENAME
• The Java interpreter looks for the file
  FILENAME.class in the current directory and loads
  it, and any additional files needed by that class

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• Introduction to Java 3D API

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Some basic packages

• Core classes
• javax.media.j3d package, it includes the
  lowest-level classes necessary in Java 3D
  programming
• Utility classes
• com.sun.j3d.utils package, it is convenient and
  powerful additions to the core
• It has 4 major categories content loaders, scene
  graph construction aids, geometry classes, and
  convenience utilities
• Abstract Windowing Toolkit (AWT)
• java.awt package, it creates a window to display
  the rendering
• Vector math classes
• javax.vecmath package, it defines vector math
  classes for points, vectors, matrices, and other
  mathematical objects

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Virtual Universe and Scene Graph

• A Java 3D program describes a virtual universe,
  which is to be rendered
• A virtual universe is created from a scene graph
• The scene graph is assembled from objects to
  define the geometry, sound, lights, location,
  orientation, and appearance of visual and audio
  objects

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How to Build a Scene Graph

• A scene graph is composed of nodes and arcs. A
  node is a data element, and arc is a relationship
  between data elements
• The nodes in the scene graph are the instances of
  Java 3D classes. The arcs represent the two kinds
  of relationship between the Java 3D instances

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Two relationships

• Parent-child relationship
• A parent node can have any number of children but
  only one parent
• A child node can have one parent and no children
• Reference relationship
• A reference associates a NodeComponent object
  with a scene graph Node. NodeComponent objects
  define the Geometry, Appearance, Material and
  Texture attributes used to render the visual
  objects
• For a single node, it can have many references

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A Scene Graph Example
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Concepts

• Each scene graph has a single Virtual Universe
• The Virtual Universe object has a Locale object
  (landmark used to determine the location of
  visual objects). It is the root of multiple
  sub-graphs
• A BranchGroup object is the root of a sub-graph
  (branch graph)
• Two kinds of sub-graph
• view branch graph
• viewing parameters (viewing location and
  direction)
• content branch graph
• Geometry, Appearance, Material, Texture,

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SceneGraphObject class

• SceneGraphObject is the superclass for nearly
  every Core and Utility Java 3D class. It has two
  subclasses
• Node
• Group
• BranchGroup, TransformGroup
• Leaf
• Shape3D, Light, Behavior, and Sound (have no
  children but may reference NodeComponents)
• NodeComponent
• Geometry, Appearance, Material, Texture, (may
  be referenced by A Leaf)

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Some Key Classes

• Node and NodeComponent
• superclasses for all the items that are added to
  a scene graph
• BranchGroup
• A Container for other objects in the scene
• Every item in the scene graph is either a
  BranchGroup, or is a child of a BranchGroup
• A BrachGroup can be a child of another
  BranchGroup
• Shape3D
• Contains information about an object in the scene
• Contains references to Geometry, Appearance,
  Material, Texture,
• Appearance
• Defines the way a shape appears in the scene,
  including texture, and attributes for many other
  settings
• TransformGroup
• Allows translations, scales and rotations to be
  preformed
• Geometry
• Superclass for all classes that allow you to add
  form to a shape
• Subclasses LineArray, TriangleArray, ....

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A Recipe for Writing Java 3D Programs

• 1. Create a Canvas3D object
• 2. Create a VirtualUniverse object
• 3. Create a Locale object, attaching it to the
  VirtualUniverse object
• 4. Construct a view branch graph
• a. Create a View object
• b. Create a ViewPlatform object
• c. Create a PhysicalBody object
• d. Create a PhysicalEnvironment object
• e. Attach ViewPlatform, PhysicalBody,
  PhysicalEnvironment, and Canvas3D objects to View
  object
• 5. Construct content branch graph(s)
• 6. Compile branch graph(s)
• 7. Insert subgraphs into the Locale

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A Simple Recipe for Writing Java 3D Programs

• 1. Create a Canvas3D Object
• 2. Create a SimpleUniverse object which
  references the Canvas3D object
• a. Customize the SimpleUniverse object
• 3. Construct content branch
• 4. Compile content branch graph (to let Java 3D
  perform optimizations on this scene graph)
• 5. Insert content branch graph into the Locale of
  the SimpleUniverse

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The SimpleUniverse Class

• The SimpleUniverse object constructor creates a
  scene graph including VirtualUniverse and Locale
  objects, and a complete view branch graph
• The view branch graph created by SimpleUniverse
  uses instances of ViewingPlatform and Viewer
  convenience classes in place of the core classes
  used to create the view branch graph
• It significantly reduces the time and effort
  needed to create the view branch graph

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Examples

• http//www.cs.ualberta.ca/anup/Courses/604/demos/
  nav.html

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Programming Assignment 1

• http//www-csfy.cs.ualberta.ca/c414/W07/assignmen
  ts/as1/C414_W07_AS1.html
• Due date Feb 7
• Submission Send E-mail to taowang_at_cs.ualberta.ca
  and CC to anup_at_cs.ualberta.ca
• You are allowed to use any other
  languages/packages. However, you have to
  demonstrate your program to your TA AND submit
  the source code BEFORE the deadline. Your TA may
  or may not install/compile/run your program. If
  you use Java 3D, you do not have to show demos.
  The source code is enough.

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Labs

• There will be NO lab work in this course. Lab
  time may be used for working on assignments, or
  discussions with TA
• Lab begins from next week, Jan 16th
• H01 500PM-650PM Tue
• H02 300PM-450PM Wed

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Q A