Opengl - Compaq AP750 - Professional - 256 MB RAM Manual

Graphics: The Workstation Difference
Figure 2 shows the complexity and regularity of several key graphics operations. They range
from simple, regular operations such as pixel write and Z-buffer operations, through a set of
operations with increasing complexity and decreasing regularity. This chart also shows
operations can increase in complexity without decreasing in regularity; this is an important point,
as these operations can be efficiently accelerated in hardware.
PowerStorm graphics integrate hardware and software components supporting a broad range of
hardware graphics accelerators through a common interface. This insulates applications from
underlying hardware, and allows you to make graphics purchasing decisions based upon
performance requirements rather than arbitrary combinations of "which graphics hardware goes
on which workstation platform and supports which applications."

OpenGL

OpenGL is quite simple in many ways. It can be described as a programming interface for three
dimensional graphics, much like Direct3D, PHIGS or a number of proprietary interfaces. But it is
also much more than that -- it is hardware, operating system, and window system independent.
OpenGL is available from dozens of computer companies. It is a standard part of Microsoft' s
Windows NT, and is supported on virtually all versions of UNIX. OpenGL is the 3D interface
for graphics hardware ranging from a simple 8-bit frame buffer to ultra high end graphics
subsystems costing several hundreds of thousands of dollars.
There are several key aspects to OpenGL. The first is that it works. Unlike some standards that
were developed in committees, OpenGL was developed to support applications development.
OpenGL has evolved and proven itself as an interface that meets the needs of software
developers. The capabilities and functions of OpenGL deliver what programmers need. Because
of this, OpenGL has rapidly become the preferred interface for applications requiring 3D
graphics.
Second is that OpenGL is an open industry standard. The OpenGL specification is controlled by
the OpenGL Architecture Review Board (ARB), which has representatives from Silicon
Graphics, Microsoft, Compaq Computer Corporation, IBM, Evans & Sutherland, and a number of
other companies. The ARB is responsible for maintaining the OpenGL specification and for
guiding the evolution of OpenGL in a public forum. Any changes to the OpenGL specification
must be formally approved by the ARB. The fact that the OpenGL specification is controlled by
the leading workstation companies and is available on all leading workstations makes it the
preferred interface for all application developers who need to have portable software.
Third, OpenGL spans both hardware and operating systems. OpenGL can be implemented
entirely in software, supporting a simple frame buffer. Many types of hardware acceleration can
be applied to OpenGL functions without impacting the interface. This means that workstation
companies can develop special hardware to make OpenGL go faster -- without affecting the
applications that call OpenGL. The fact that OpenGL graphics can be cleanly accelerated with
specialized graphics hardware -- with no impact to application software -- is extremely
advantageous to computer companies, application developers, and customers who purchase
systems and applications. Compaq uses OpenGL to transparently integrate graphics hardware
and software, providing a foundation for a complete family of graphics accelerators.
The ability of OpenGL to span operating systems is based on a single design decision: OpenGL
does nothing but 3D rendering. Open GL extends the capabilities of any underlying windowing
system. A windowing system provides 2D graphics functions, window and screen management,
user interaction mechanisms, text display and manipulation, and similar capabilities. OpenGL
simply adds 3D rendering support to the 2D windowing system. This allows OpenGL to support
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