Graphics Reference
In-Depth Information
for real-time applications such as games and simulation. So simple “graphics
cards”—cards that contained a graphics memory and acted as a simple frame-
buffer—were replaced by cards that included onboard graphics operations
and eventually the full fixed-function graphics pipeline that we discussed
in the previous chapter. These provided a great increase in graphics speed,
but the graphics audience wanted more. It's a truism is that you can never be
too thin or too rich—but in computer graphics you can never have too much
speed or too much resolution or too many colors. As a community, we are very
greedy—and proud of it!
While simple graphics cards were a great improvement over software
rendering, they were restricted to what the fixed-function pipeline could do,
and they did not support many effects and capabilities that a creative graphics
programmer might want. The next step, where we are now, was to make the
cards programmable so that extra functionality could be added as needed. With
emerging systems such as OpenGL ES (for embedded systems such as PDAs
and cell phones) having no fixed-function pipeline, and with core OpenGL
4.0 replacing the fixed-function approach with a shader-required approach, it
seems clear that shaders are increasingly central to computer graphics appli-
cations and that anyone planning to do serious graphics work will need to
become skilled in shader programming and development.
History of Shaders
Even though GPU-based shaders are a relatively recent phenomenon, the
overall history of shaders goes back about 30 years. Looking back, it could be
considered to have started in 1977, with the release of a low budget movie that
was to grow into a cult phenomenon: Star Wars Episode IV: A New Hope .
Star Wars IV was revolutionary in using models and robotic-controlled
cameras to create the illusion of actual moving space ships in a ierce batle. It
did use computer graphics, but not much. What it did use was well below the
capabilities of that time, but the astonishing box office success of the movie
demonstrated that special effects sell tickets. But for future movies, it was real-
ized that it would be difficult to greatly scale up the use of physical models.
However, George Lucas was a man with a vision—and, more importantly, the
movie had given him the funds to implement that vision.
Turning to computer graphics, Lucas hired Ed Catmull and others from
the New York Institute of Technology around 1980 to become the Computer
Division of Lucasfilm. Their efforts at Lucasfilm had three thrusts:
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