Welcome to the OpenGL Performer application development environment. OpenGL Performer provides a programming interface (with ANSI C and C++ bindings) for creating real-time graphics applications and offers high-performance rendering in an easy-to-use 3D graphics toolkit. OpenGL Performer interfaces with the OpenGL graphics library; this library combined with the IRIX or Linux operating system forms the foundation of a powerful suite of tools and features for creating real-time 3D graphics applications.
Use OpenGL Performer for building visual simulation applications and virtual reality environments, for rapid rendering in on-air broadcast and virtual set applications, for assembly viewing in large simulation-based design tasks, or to maximize the graphics performance of any application. Applications that require real-time visuals, free-running or fixed-frame-rate display, or high-performance rendering will benefit from using OpenGL Performer.
OpenGL Performer drastically reduces the work required to tune your application's performance. General optimizations include the use of highly tuned routines for all performance-critical operations and the reorganization of graphics data and operations for faster rendering. OpenGL Performer also handles SGI architecture-specific tuning issues for you by selecting the best rendering and multiprocessing modes at run time, based on the system configuration.
OpenGL Performer is an integral part of the SGI visual simulation systems. It provides the interface to advanced features available exclusively with the SGI product line, such as the InfiniteReality, Silicon Graphics Octane, Silicon Graphics O2, Impact, and VPro graphics subsystems . OpenGL Performer teamed with InfiniteReality or OCTANE provide a sophisticated image generation system in a powerful, flexible, and extensible software environment. OpenGL Performer is also tuned to operate at peak efficiency on each graphics platform produced by SGI; you do not need the hardware sophistication of InfiniteReality graphics to benefit from OpenGL Performer.
To use OpenGL Performer, you should be comfortable programming in ANSI C or C++. You should also have a fairly good grasp of graphics programming concepts. Terms such as “texture map” and “homogeneous coordinate” are not explained in this guide. It helps if you are familiar with the OpenGL library. If you are a newcomer to these topics, see the references listed under “Bibliography” at the end of this introduction and examine the glossary for definitions of terms or usage unique to OpenGL Performer.
On the other hand, though you need to know a little about graphics, you do not have to be a seasoned C (or C++) programmer, a graphics hardware guru, or a graphics-library virtuoso to use OpenGL Performer. OpenGL Performer puts the engineering expertise behind SGI hardware and software at your fingertips, so you can minimize your application development time while maximizing the application's performance and visual impact.
For a concise description of OpenGL Performer basics, see OpenGL Performer Getting Started Guide.
The best way to get started is to read OpenGL Performer Getting Started Guide. If you like learning from sample code, turn to Chapter 1, “Getting Acquainted With OpenGL Performer,” which takes you on a tour of some demo programs. These programs let you see for yourself what OpenGL Performer does. Even if you are not developing a visual simulation application, you might want to look at the demos to see high-performance rendering in action. At the end of Chapter 2, “Setting Up the Display Environment” you will find suggestions pointing to possible next steps; alternatively, you can browse through the summary below to find a topic of interest.
This guide is divided into the following chapters and appendixes:
Chapter 1, “OpenGL Performer Programming Interface”, describes the fundamental ideas behind the OpenGL Performer programming interface.
Chapter 2, “Setting Up the Display Environment”, describes how to set up rendering pipelines, windows, and channels (cameras).
Chapter 3, “Nodes and Node Types”, describes the data structures used in OpenGL Performer's memory-based scene-definition databases.
Chapter 4, “Database Traversal”, explains how to manipulate and examine a scene graph.
Chapter 5, “Frame and Load Control”, explains how to control frame rate, synchronization, and dynamic load management. This chapter also discusses the load management techniques of multiprocessing and level-of-detail.
Chapter 6, “Creating Visual Effects”, describes how to use environmental, atmospheric, lighting, and other visual effects to enhance the realism of your application.
Chapter 7, “Importing Databases”, describes database formats and sample conversion utilities.
Chapter 8, “Geometry”, discusses the classes used to create geometry in Performer scenes.
Chapter 9, “Graphics State”, describes the graphics state, which contains all of the fields that together define the appearance of geometry.
Chapter 10, “Shader”, describes the shader, a mechanism which allows complex rendering equations to be applied to Performer objects.
Chapter 11, “Using DPLEX and Hyperpipes”, describes how to use DPLEX, which permits multiple InfiniteReality2 or InfiniteReality pipelines in an Onyx2 system to work simultaneously on a single visual application.
Chapter 12, “ClipTextures”, describes how to work with large, high-resolution textures.
Chapter 13, “Windows”, describes how to create, configure, manipulate, and communicate with a window in OpenGL Performer.
Chapter 14, “pfPipeWindows and pfPipeVideoChannels”, describes the unified window and video channel control and management provided by pfPipeWindows and pfPipeVideoChannels.
Chapter 15, “Managing Nongraphic System Tasks”, describes clocks, memory allocation, synchronous I/O, error handling and notification, and search paths.
Chapter 16, “Dynamic Data”, describes how to connect pfFlux, pfFCS, and pfEngine nodes, which together can be used for animating geometries.
Chapter 17, “Active Surface Definition”, describes the Active Surface Definition (ASD): a library that handles real-time surface meshing and morphing.
Chapter 18, “Light Points”, describes the calligraphic lights, which are intensely bright lights.
Chapter 19, “Math Routines”, details the comprehensive math support provided as part of OpenGL Performer.
Chapter 20, “Statistics”, discusses the various kinds of statistics you can collect and display about the performance of your application.
Chapter 21, “Performance Tuning and Debugging”, explains how to use performance measurement and debugging tools and provides hints for getting maximum performance.
Chapter 22, “Programming with C++”, discusses the differences between using the C and C++ programming interfaces.
You can find the sample code for all of the sample OpenGL Performer applications installed under /usr/share/Performer/src/pguide.
This guide uses the following typographical conventions:
| Bold | Used for function names, with parentheses appended to the name. Also, bold lowercase letters represent vectors, and bold uppercase letters denote matrices. | |
| Italics | Indicates variables, book titles, and glossary-worthy items. | |
| Fixed-width | Used for filenames, operating system command names, command-line option flags, code examples, and system output. | |
| Bold Fixed-width | Indicates user input, items that you should type in from the keyboard. |
Note that in some cases it is convenient to refer to a group of similarly named OpenGL Performer functions by a single name; in such cases an asterisk is used to indicate all the functions whose names start the same way. For instance, pfNew*() refers to all functions whose names begin with “pfNew”: pfNewChan(), pfNewDCS(), pfNewESky(), pfNewGeode(), and so on.
The OpenGL Performer series include the following in printed and online versions:
OpenGL Performer Programmer's Guide (007-1680-nnn)
OpenGL Performer Getting Started Guide (007-3560-nnn)
To read these online books, point your browser at the following:
http://techpubs.sgi.com/library/dynaweb_bin/0620/bin/nph-dynaweb.cgi/dynaweb/SGI_Developer/Perf_PG/@Generic__BookView
For general information about OpenGL Performer, point your browser at the following:
http://www.sgi.com/software/Performer
Electronic forum for discussions about OpenGL Performer:
The info-performer mailing list provides a forum for discussion of OpenGL Performer including technical and nontechnical issues. Subscription requests should be sent to info-performer-request@sgi.com. Much like the comp.sys.sgi.* newsgroups on the Internet, it is not an official support channel but is monitored by several interested SGI employees familiar with the toolkit.
For other related reading, see “Bibliography”.
You should be familiar with most of the concepts presented in the first few books listed here—notably Computer Graphics: Principles and Practice and OpenGL Programming Guide—to make the best use of OpenGL Performer and this programming guide. Most of the other books listed here, however, delve into more advanced topics and are listed as further reading for those interested. Information is also provided on electronic access to SGI's files containing answers to frequently asked OpenGL Performer questions.
For a general treatment of a wide variety of graphics-related topics, see the following:
For specific topics of interest to developers using OpenGL Performer, also see the following:
Akeley, Kurt, "RealityEngine Graphics", Computer Graphics Annual Conference Series (SIGGRAPH), 1993. pp. 309-318.
Jones, Michael; Clay, Sharon; Helman, James; Rohlf, John; Bigos, Andy; Tarbouriech, Philippe; Hoffman, Wes; Johnston, Eric; Limber, Michael; and Watson,Scott, "Designing Real-Time 3D Graphics for Entertainment," Course Notes of 1997 SIGGRAPH Course #6.
Willis, L.R., Jones, M.T., and Zhao, J., "A Method for Continuous Adaptive Terrain," Proceedings of the 1996 Image Conference. June 23-28, 1996, Scottsdale Arizona.
Montrym, John S.; Baum, Daniel R.; Dignam, David L.; Migdal, Christopher J., "InfiniteReality: A Real-Time Graphics System," Computer Graphics Annual Conference Series (SIGGRAPH), 1997. pp. 293-302.
Rohlf, John and Helman, James, "IRIS Performer: A High Performance Multiprocessing Toolkit for Real-Time 3D Graphics," Computer Graphics Proceedings, Annual Conference Series (SIGGRAPH), 1994, pp. 381-394.
Shoemake, Ken. “Animating Rotation with Quaternion Curves,” SIGGRAPH `85 Conference Proceedings Vol 19, Number 3, 1985.
For information about OpenGL, see the following:
Neider, Jackie, Tom Davis, and Mason Woo, OpenGL Programming Guide. Reading, Mass.: Addison-Wesley Publishing Company, Inc., 1993. A comprehensive guide to learning OpenGL.
OpenGL Architecture Review Board, OpenGL Reference Manual. Reading, Mass.: Addison-Wesley Publishing Company, Inc., 1993. A compilation of OpenGL man pages.
The OpenGL Porting Guide, a SGI publication shipped in IRIS InSight-viewable on-line format. Provides information on updating IRIS GL-based software to use OpenGL.
In conjunction with OpenGL, you may wish to learn about the X Window System, the Xt Toolkit Intrinsics library, and IRIS IM (though note that if you use OpenGL Performer's pfWindow routines, windows are handled for you; in that case you don't need to know about any of these topics). For information on X, Xt, and Motif, see the O'Reilly X Window System Series, Volumes 1, 2, 4, and 5 (usually referred to simply as “O'Reilly” with a volume number):
Nye, Adrian, Volume One: Xlib Programming Manual. Sebastopol, California: O'Reilly & Associates, Inc., 1991.
Volume Two: Xlib Reference Manual, published by O'Reilly & Associates, Inc., Sebastopol, California.
Nye, Adrian and O'Reilly, Tim, Volume Four: X Toolkit Intrinsics Programming Manual, published by O'Reilly & Associates, Inc., Sebastopol, California.
Volume Five: X Toolkit Intrinsics Reference Manual, published by O'Reilly & Associates, Inc., Sebastopol, California.
For information on IRIS IM, SGI's port of OSF/Motif, and on making your application interact well with the SGI desktop, see these SGI publications:
IRIS IM Programming Guide
IRIX Interactive Desktop User Interface Guidelines
IRIX Interactive Desktop Integration Guide
All three of these books are shipped in IRIS InSight-viewable online format.
For information about visual simulation and the use of simulation systems in training and research, see the following:
Rolfe, J.M. and Staples, R.J., eds. Flight Simulation. Cambridge: Cambridge University Press, 1986. Provides a comprehensive overview of visual simulation from the basic equations of motion to the design of simulator cabs, optical and display systems, motion bases, and instructor/operator stations. Also includes a historical overview and an extensive bibliography of visual simulation and aerodynamic simulation references.
Rougelot, Rodney S. “The General Electric Computer Color TV Display,” in Faiman, M., and J. Nievergelt, eds. Pertinent Concepts in Computer Graphics. Urbana, Ill.:University of Illinois Press, 1969, pp. 261-281. This extensive report gives an excellent overview of the origins of visual simulation. It shows many screen images of the original systems developed for various NASA programs and includes the first real-time textured image. This article provides the basis for understanding the historical development of computer image generation and real-time graphics.
Schacter, Bruce J., ed. Computer Image Generation. New York: John Wiley & Sons, Inc., 1983. Reviews the computer image generation process and provides a detailed analysis of early approaches to system design and implementation. The bibliography refers to early papers by the designers of the first image-generation systems.
Stevens, Brian L., and Lewis, Frank L. Aircraft Control and Simulation. New York: John Wiley & Sons, Inc., 1992. This book describes the complete implementation of a flight-dynamics model for the F-16 fighter aircraft. It provides the basic equations of motion and explains how the more complex issues are handled in practice. Some source code, in Fortran, is included.
The following books are excellent sources for information on virtual reality:
Kalawsky, Roy S. Science of Virtual Reality and Virtual Environments. Reading, Mass.: Addison-Wesley Publishing Company, Inc., 1993.
Möller, Tomas, and Haines, Eric. Real Time Rendering. A K Peters, Ltd, 1999. Explains the concepts and algorithms used in computer-aided design, visual simulation, virtual reality worlds, and games. Focuses on the graphics pipeline, with chapters on transforms, optimization, visual appearance, polygon manipulation, collision detection, and special effects. The ideal springboard to the techniques used in OpenGL Performer.
These two books address geometric reasoning in general, rather than any specifically computer-related or OpenFL Performer-specific topics:
The proceedings of the I/ITSEC (Interservice/Industry Training, Simulation, and Education Conference) are a primary source of published visual simulation experience. In the past this conference has been known as the National Training Equipment Center/Industry Conference (NTEC/IC) and the Interservice/Industry Training Equipment Conference (I/ITEC). Proceedings are available from the National Technical Information Service (NTIS). Here are NTIS order numbers for several of the older proceedings:
Seventh N/IC, November, 1974: AD-A000-970 NTEC
Eighth N/IC, November, 1975: AD-A028-885 NTEC
Ninth N/IC, November, 1976: AD-A031-447 NTEC
Tenth N/IC, November, 1977: AD-A047-905 NTEC
Eleventh N/IC, November, 1978: AD-A061-381 NTEC
First I/ITEC, November, 1979: AD-A077-656 NTEC
Third I/ITEC, November, 1981: AD-A109-443 NTEC
The IMAGE Society is dedicated solely to the advancement of visual simulation technology and its applications. It holds conferences and workshops, the proceedings of which are an excellent source of advice and guidance for visual simulation developers. The society can be reached through e-mail at image@asu.edu. Some of the IMAGE proceedings published by the Air Force Human Resources Lab AFHRL at Williams AFB prior to the formation of the IMAGE Society are also available from the NTIS. Order numbers are:
IMAGE, May, 1977: AD-A044-582 AFHRL
IMAGE II (closing), July, 1981: AD-A104-676 AFHRL
IMAGE II (proceedings), November, 1981: AD-A110-226 AFHRL
The Society of Photo-Optical Instrumentation Engineers (SPIE) also has articles of interest to visual simulation developers in their conference proceedings. Some of the interesting publications are:
Vol. 17, Photo-Optical Techniques in Simulators, April, 1969
Vol. 59, Simulators & Simulation, March, 1975
Vol. 162, Visual Simulation & Image Realism, August, 1978
Aviation Week & Space Technology, January 17, 1983. Special issue on visual simulation.
Fischetti, Mark A., and Carol Truxal. “Simulating the Right Stuff.” IEEE Spectrum, March, 1985, pp. 38-47.
Schacter, Bruce. “Computer Image Generation for Flight Simulation.” IEEE Computer Graphics & Applications, October, 1981, pp. 29-68.
Schacter, Bruce, and Narendra Ahuja. “A History of Visual Flight Simulation.” Computer Graphics World, May, 1980, pp. 16-31.
Tucker, Jonathan B., “Visual Simulation Takes Flight.” High Technology Magazine, December, 1984, pp. 34-47.
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