Geometry calculation in java.Which includes finding area and perimeter at the same time
Java 3D Programming About this book Java 3D is a client−side Java application programming interface (API) developed at Sun Microsystems for rendering interactive 3D graphics using Java. Using Java 3D you will be able to develop richly interactive 3D applications, ranging from immersive games to scientific visualization applications. Who should read it? Java 3D Programming is aimed at intermediate to experienced Java developers. Previous experience in graphics programming (OpenGL and Swing, for example) will be very useful, but it's not a prerequisite. No book stands alone and you should make good use of the many online resources and books listed in appendix B and the bibliography. Readers new to Java 3D should definitely download Sun's excellent (free) Java 3D tutorial. This book is intended to serve as a companion to the Sun API documentation and the Java 3D tutorial. How is it organized? The book has 18 chapters, plus three appendices and a bibliography. Each chapter is fairly self−contained or explicitly references related chapters, allowing you to focus quickly on relevant material for your problem at hand. I have ordered the material so that, if you were starting a project from scratch, progressing in the book would mirror the design questions you would face as you worked through your design study and development efforts. More commonly used material is, in general, closer to the beginning of the book. Chapter 1 focuses on getting started with Java 3D, system requirements, running the examples in the book, plus a look at the strengths and weaknesses of Java 3D. Chapter 2 introduces some of the fundamentals of 3D graphics programming, such as projection of points from 3D to 2D coordinates, lighting, and hidden surface removal. Chapter 3 gets you started with Java 3D programming, from setting up your development environment and resources to running your first application. Chapter 4 explains the fundamental data structure in Java 3D, the scenegraph. Aspects of good scenegraph design are described using an example application for discussion. Chapter 5 is a reference to Java 3D's scenegraph nodes, along with usage instructions and examples. Chapter 6 explains the elements of the Java 3D scenegraph rendering model and guides you in your choice of VirtualUniverse configuration. Chapter 7 takes a step back and examines data models for 3D applications. Choosing a suitable data model involves understanding your interaction and performance requirements. Chapter 8 is a reference to creating geometry to be rendered by Java 3D. Chapter 9 covers the elements of the Java 3D Appearance class, used to control the rendered appearance of the geometric primitives in your scene. Chapter 10 illuminates the Java 3D lighting model and shows you how to create powerful lighting for your scene. 1 Chapter 11 introduces the Java 3D behavior model, which allows you to attach code to the objects in your scene. Examples illustrate both keyboard and mouse behaviors for graphical user interfaces. Chapter 12 expands upon the discussion of behaviors, covering the Interpolator behaviors, used to control geometry attributes using the Alpha class. Chapter 13 describes how to write your own custom behaviors and register them with Java 3D for invocation. Example behaviors for debugging and complex physical animation as well as others are presented. Chapter 14 explains how to increase the realism of your scenes by applying bitmaps to your geometry using the process of texture mapping. Chapter 15 highlights some of the utility classes provided with Java 3D for operations such as triangulation and loading of input data. Chapter 16 delves into more techniques valuable for interacting with 3D scenes, object interaction using the mouse for selection of 3D objects, and performing collision detection between 3D objects. Chapter 17 shows, through example, how to build Java 3D applications that use the Swing packages for 2D user interface elements, and can be distributed as Java applets for use from a web browser. Chapter 18 goes low−level to explain some of the implementation details of the Java 3D API. The aim is to give you a greater appreciation for what is going on behind the scenes and help you optimize your applications. Appendix A cross−references all the examples by chapter and includes instructions for downloading, installing, and running the example code from the publisher's web site. Appendix B includes a comprehensive listing of programming and graphics resources online. Print references are provided in the bibliography. Appendix C explains the Primitive utility class, its geometry cache, and the GeomBuffer class, along with tips and caveats. Source code The book contains over 30,000 lines of example code, including some reusable library code that I hope will contribute to the collective understanding of the Java 3D community. Code of particular interest is shown in boldface. Appendix A contains a list of the example Java 3D applications and applets developed for this book, as well as detailed instructions for running the examples. The code itself is identified in the text by an initial reference to its location at http://www.manning.com/selman, the Manning web site for this book. Typographical conventions Italic typeface is used to introduce new terms. Courier typeface is used to denote code samples as well as elements and attributes, method names, classes, interfaces, and other identifiers. Courier bold typeface is used to denote code of special interest. Code line continuations are indented. 2 How to use the book I have tried to organize many of the topics in the book in an order appropriate for developers designing and building a new Java 3D application. I would suggest initially reading or skimming the chapters sequentially to get an overall feel for the design of your application, and then returning to specific chapters and examples for reference material as required. Please note that the example source code for the book is provided under the GNU General Public License (GPL) (http://www.gnu.org/licenses/licenses.html). I encourage you to modify and distribute the source code in accordance with the spirit of open source and the GPL license. If you still need help or have questions for the author, please read about the unique Author Online support that is offered from the publisher's web site. Author Online Purchase of Java 3D Programming includes free access to a private web forum run by Manning Publications where you can make comments about the book, ask technical questions, and receive help from the author and from other users. To access the forum and subscribe to it, point your web browser to http://www.manning.com/selman. This page provides information on how to get on the forum once you are registered, what kind of help is available, and the rules of conduct on the forum. Manning's commitment to readers is to provide a venue where a meaningful dialog between individual readers and between readers and the author can take place. It is not a commitment to any specific amount of participation on the part of the author, whose contribution to the AO remains voluntary (and unpaid). We suggest you try asking the author some challenging questions, lest his interest stray! The Author Online forum and the archives of previous discussions will be accessible from the publisher's web site as long as the book is in print. 3 CHAPTER 1 What is Java 3D and is it for me? 1.1 Strengths 1.2 Weaknesses 1.3 System requirements (developer and end user) 1.4 Expected performance 1.5 Running the examples 1.6 Summary Java 3D is an application programming interface (API) developed at Sun Microsystems for rendering interactive 3D graphics using the Java programming language. Java 3D is a client−side Java API. Other examples of Sun client−side APIs include the Abstract Windows Toolkit (AWT) and Java Foundation Classes (JFC/Swing), which are both Java class libraries for building applications with a Graphical User Interface (GUI). The client−side Java APIs are in contrast to Sun’s server−side APIs such as Enterprise Java−Beans (EJB) and the other components of Java 2 Enterprise Edition (J2EE). Making 3D graphics interactive is a long−standing problem, as evidenced by its long history of algorithms, APIs, and vendors. Sun is not a major player in the 3D graphics domain, although its hardware has long supported interactive 3D rendering. The dominant industry standard for interactive 3D graphics is OpenGL, created by Silicon Graphics (SGI). OpenGL was designed as a cross−platform rendering architecture and is supported by a variety of operating systems, graphics card vendors, and applications. The OpenGL API is written in the C programming language, and hence not directly callable from Java. A number of open source and independent programming efforts have provided simple Java wrappers over the OpenGL API that allow Java programmers to call OpenGL functions, which are then executed in native code that interacts with the rendering hardware. One of the most popular is GL4Java, which you can find at http://www.jausoft.com/gl4java/. However, there are few advantages to using a Java wrapper over OpenGL, as opposed to coding in C and calling OpenGL directly. Although programmers can use the more friendly Java APIs, they must incur the overhead of repeated calls through the Java Native Interface (JNI) to call the native OpenGL libraries. Java 3D relies on OpenGL or DirectX to perform native rendering, while the 3D scene description, application logic, and scene interactions reside in Java code. When Sun set out to design Java 3D, although they did not have the resources or industry backing to replace OpenGL, they wanted to leverage more of Java’s strengths as an object−oriented programming (OOP) language instead of merely delegating to a procedural language such as C. Whereas OpenGL’s level of description for a 3D scene consists of lists of points, lines, and triangles, Java 3D can describe a scene as collections of objects. By raising the level of description and abstraction, Sun not only applied OOP principles to the graphics domain, but also introduced scene optimizations that can compensate for the overhead of calling through JNI. 1.1 Strengths 4 The foremost strength of Java 3D for Java developers is that it allows them to program in 100 percent Java. In any sizeable 3D application, the rendering code will compose only a fraction of the total application. It is therefore very attractive to have all the application code, persistence, and user interface (UI) code in an easily portable language, such as Java. Although Sun’s promise of Write−Once−Run−Anywhere is arguably more of a marketing dream than a reality, especially for client−side programming, Java has made important inroads toward enabling application developers to write applications that can be easily moved between platforms. The platforms of most interest today are Microsoft Windows 98/NT/2000, Sun Solaris, LINUX, and Macintosh OS X. Java has arguably become the language of networked computing and the Internet. High−level support for remote method invocation (RMI), object serialization, platform independent data types, UNICODE string encoding, and the security model all provide persuasive arguments for adopting the Java language for applications that are increasingly gravitating away from a desktop−centric worldview. Many of the state−of−the−art 3D graphics applications being built with Java 3D today