What is OpenGL? 
by Dale Rogerson
What is OpenGL? Benefits for graphics workstation users Moving toward 3-D Windows Until recently, fast, high-quality, 3-D graphics like those produced for the movie Jurassic Park could only be built on an expensive platform such as Silicon Graphics' IRIS workstation. This meant that the quality of graphical animation that could be produced on less expensive, Windows-based PCs suffered greatly by comparison.
However, Windows NT version 3.5-and the Win32 API now include OpenGL, a 3-D graphics library that will someday enable every PC to be a high-end, threedimensional graphics platform.
The inclusion of OpenGL with Windows NT opens up a number of possibilities for the developer community. One result will be a huge expansion in the number of programmers who have the opportunity to develop 3-D applications or to enhance their applications by adding 3-D graphics.
Also, more high-end graphics applications will be ported to the PC. In addition, OpenGL will eventually be added to Windows 95, which will dramatically increase the installed base of OpenGL users, further encouraging development of OpenGL applications for a greatly expanded market.
(For a preview of OpenGL, take a look at the new OpenGL screen savers included with Windows NT version 3.5: 3-D Flying Objects and 3-D Pipes.)
Okay, so what is OpenGL?OpenGL does not manage windows, read input, or write files. Windows NT, Windows, or some other operating system does the job of managing the windows. An application gives OpenGL a piece of a window or bitmap on which to render.
Silicon Graphics Inc. (commonly known as SGI) originally developed GL, a 3-D graphics language, for its 3-D graphics machine, the IRIS. The process of potting it to another system proved extremely difficult, however. So SGI decided to change GL to make it easier to port to different hardware, operating systems, and windowing systems. The result was OpenGL.
While SGI still maintains IRIS GL, all new work and enhancements are being made to OpenGL. The enhancements and changes to OpenGL are decided by the Architecture Review Board (ARB), whose founding members are Digital Equipment Corporation, IBM, Intel, Microsoft, and SGI.
Benefits for graphics workstation usersSo if you don't have $50,000 to drop, the addition of OpenGL to Windows NT provides a number of benefits. For the graphics workstation community, it is low- cost, scalable, and portable. It means that Windows NT can now serve as a low-cost platform for developing and running high-end graphics applications, including CAD/CAM (computer-aided design/computer-aided manufacturing), and thus can replace more expensive graphics workstations. This means a standard Pentiumbased PC can become the basis for a graphics workstation.
Windows NT runs on small, portable laptops and large, multiple-processor file servers. You can easily try out 3-D applications or application development on your existing desktop computer and upgrade when you need the extra power. It also runs on the 386, 486, Pentium, MIPS, Alpha AXP, and PowerPC processors.
In addition, Windows NT can easily run standard Windows-based applications. The same system that runs your advanced graphics applications can run word processors, spreadsheets, and other applications for Windows. No need for multiple computers, expensive proprietary applications, or troublesome emulators.
Moving toward 3-D WindowsThe Developer Network Development Library is your best place to get started learning about and using OpenGL. The OpenGL Programmer's Reference appears in the January release of the Development Library as part of the product documentation for the Win32 Software Development Kit. In addition, you'll find various technical articles about OpenGL under Technical Articles/Windows (32-bit)/ GDI in the Development Library.