 The magazine of the Melbourne PC User Group OpenGL - For the Bookshelf Major Keary majkeary@netscape.com.au |
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Open GL
A term common in descriptions of GUI programming is widget set, which
means "a group of screen structures (menu, button, scroll bar, etc.) provided in a graphical interface"
(Freedman: The Computer Desktop Encyclopedia). Widget derives from windows and gadget, and was coined
by Unix programmers for what their Windows counterparts call controls.
"OpenGL is a platform- and language-independent API standard for three-dimensional vector graphics, and is
used on many platforms" (Dalheimer: Programming with Qt). Another description, from the back cover of
OpenGL Programming Guide, is more realistic: "[it] is a powerful software interface used to produce
high-quality computer generated images and interactive applications using 2D and 3D objects and color bitmaps
and images". WinNT and some Unix/Linux systems come with OpenGL libraries.
The use of `Open' in the program's name indicates that it is open source software; while originally developed
by Silicon Graphics Inc. (SGI), OpenGLs further development is controlled by the Architecture Review Board
(ARB), which is an "industry consortium responsible for guiding the evolution of OpenGL and related
technologies". The consortium includes SGI, IBM, Intel, Microsoft, and other well-known corporations. There
are platform-specific extensions, such as GLX (X Windows), AGL (Mac), PGL (OS/2 Warp), and WGL (MS
Win95/98/NT).
This title, OpenGL Programming Guide, is about OpenGPs functions and syntax. For information about how OpenGL
operates on data there is a companion volume, OpenGL Reference Manual. Much of that information is
also available at http://www.opengl.org.
The third edition of the programming guide covers version 1.2 and its new features (3D texture mapping,
multitexturing, new pixel storage formats, specular lighting, OpenGL imaging subset, and new routines). It
is, as the title says, a guide for programmers. All aspects of OpenGL are covered, beginning with the simple
(a `hello' exercise and creating a white rectangle on a black background) through progressively more complex
tasks (such as drawing an icosahedron, texture mapping, and lighting). Also discussed are performance
enhancing techniques, cross-platform techniques, and the extensions available for other platforms.
Apart from the extensive use of sample code (available for download from a Web site), there are mathematical
explanations. OpenGL is not a visual tool that enables users to draw something using a tool palette and then
save the result as code. OpenGL requires technical knowledge, and this is where programmers will find that
information. The book is both a practical guide and a technical reference that enables programmers to compute
the data required by various commands.
| Mason Woo et al.: OpenGL Programming Guide 3rd edn. ISBN 0-201-60458-2 Published by Addison-Wesley,730 pp., RRP $74.95 |
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Reprinted from the August 2000 issue of PC Update, the magazine of Melbourne PC User Group, Australia
