Video Hardware - Upgrading and Repairing PCs - page 797

erally S-video or composite video. The resolution that these devices display on a TV set
or record on videotape often is limited to VGA (640×480) or SVGA (800×600).
Toconnect yourPCtoanHDTVmonitor,itispreferable touseadigital signal viaaDVI,
HDMI, or DisplayPort connection. If your current video adapter only has analog VGA
output, you'll want to upgrade to a video adapter with a DVI, HDMI, or DisplayPort di-
gitaloutput.BecausemostHDTVsuseHDMI,ifyourvideocardhasDVIorDisplayPort,
you can use a DVI-to-HDMI or DisplayPort-to-HDMI adapter if necessary. If you need
HDCP support for watching HD premium content, make sure your display and card sup-
port HDCP. Otherwise, you may not be able to watch the program or it may be displayed
at reduced resolution.
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. With the introduc-
tion of the Aero desktop in Windows Vista and later, 3D imaging is even utilized in the
userinterface,joiningotherfull-motion3Dusessuchassports,first-personshooters,team
combat, driving, and many other types of PC gaming. Because even low-cost integrated
chipsets offer some 3D support, virtually any user of a recent-model computer can enjoy
3D lighting, perspective, texture, and shading effects.
Note
At a minimum, enabling the Windows Aero interface in Vista and later requires graphics
hardware that supports DirectX 7 3D graphics; however, for maximum functionality, graph-
ics hardware that supports DirectX 9 or greater is required. Games are now being released
that require DirectX 11, which is not available for Windows XP and earlier versions.
How 3D Accelerators Work
To construct an animated 3D sequence, a computer can mathematically animate the se-
quences between keyframes. A keyframe identifies a specific point. A bouncing ball, for
example, can have three keyframes: up, down, and up. Using these frames as reference
points, 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 ,
aslightlymoreeffectivetechnique,involvestheassignmentofcolorstospecificpointson
a shape. The points are then joined using a smooth gradient between the colors.