Specifications

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Chapter 15 Video Hardware
As Table 15.18 notes, some video cards that use a chipset capable of multiple-monitor support might
not provide the additional DVI or VGA connector necessary to enable that support. Table 15.18 does
not include video chipsets that support TV-out or video in-video out (VIVO) but do not support a sec-
ond CRT or LCD display.
Caution
Some vendors whose cards provide a single VGA or DVI port (DVI-I ports can be converted to VGA with an adapter) and
a TV-out port refer to such cards as “supporting multiple monitors.” Table 15.18 lists only chipsets or cards that support
two or more CRT or LCD displays.
3D Graphics Accelerators
Since the late 1990s, 3D acceleration—once limited to exotic add-on cards designed for hardcore game
players—has become commonplace in the PC world. Although mainstream business users are not likely
to encounter 3D imaging until the next major release of Windows (code-named Longhorn) is released in
2006, full-motion 3D graphics are used in sports, first-person shooters, team combat, driving, and many
other types of PC gaming. Because even low-cost integrated chipsets offer some 3D support and 3D video
cards are now in their sixth generation of development, virtually any user of a recent-model computer
has the ability to enjoy 3D lighting, perspective, texture, and shading effects in her favorite games. The
latest 3D sports games provide lighting and camera angles so realistic that a casual observer could almost
mistake the computer-generated game for an actual broadcast, and the latest 3D accelerator chips enable
fast PCs to compete with high-performance dedicated game machines, such as Sony’s PlayStation 2,
Nintendo’s GameCube, and Microsoft’s Xbox, for the mind and wallet of the hard-core game player.
Note
At a minimum, Longhorn requires graphics hardware that supports DirectX 7 3D graphics; however, for maximum function-
ality of the 3D GUI, graphics hardware that supports DirectX 9 or greater is required.
How 3D Accelerators Work
To construct an animated 3D sequence, a computer can mathematically animate the sequences
between keyframes. A keyframe identifies specific points. A bouncing ball, for example, can have three
keyframes: up, down, and up. Using these frames as a reference point, the computer can create all the
interim images between the top and bottom. This creates the effect of a smoothly bouncing ball.
After it has created the basic sequence, the system can then refine the appearance of the images by
filling them in with color. The most primitive and least effective fill method is called flat shading, in
which a shape is simply filled with a solid color. Gouraud shading, a slightly more effective technique,
involves the assignment of colors to specific points on a shape. The points are then joined using a
smooth gradient between the colors.
A more processor-intensive, and much more effective, type of fill is called texture mapping. The 3D
application includes patterns—or textures—in the form of small bitmaps that it tiles onto the shapes
in the image, just as you can tile a small bitmap to form the wallpaper for your Windows desktop.
The primary difference is that the 3D application can modify the appearance of each tile by applying
perspective and shading to achieve 3D effects. When lighting effects that simulate fog, glare, direc-
tional shadows, and others are added, the 3D animation comes very close indeed to matching reality.
Until the late 1990s, 3D applications had to rely on support from software routines to convert these
abstractions into live images. This placed a heavy burden on the system processor in the PC, which
has a significant impact on the performance not only of the visual display, but also of any other
applications the computer might be running. Starting in the period from 1996 to 1997, chipsets on
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