Hardware Autopsy
r&dBREAKING DOWN TECH —PRESENT AND FUTURE
applies a weighted blend of the colors of the
object and its background. If the multisampling
algorithm takes two samples of each pixel, it’s
referred to as 2x AA. If it takes four samples,
it’s considered 4x AA, and so on.
Curved lines, obviously, will appear less
jagged as the level of sampling increases;
but multisampling is not a panacea. Basic
multisampling isn’t effective, for example, in
situations where a game developer depicts a
three-dimensional object by wrapping a large
bitmap containing transparent regions around
a few polygons. This is a common technique
used to portray such ordinary objects as
chain-link fences and foliage that would be dif-
fi cult to produce as true 3D models. Because
there’s no real edge in these bitmaps, there’s
nothing for the AA algorithm to latch onto.
ATI and Nvidia, therefore, have each devised
hybrid techniques of supersampling and multi-
sampling to take advantage of the strengths of
each while avoiding their shortcomings.
ATI calls its technology “adaptive
antialiasing,” while Nvidia describes
its solutions as “transparency adaptive
supersampling” and “transparency adap-
tive multisampling.” Both techniques take
multiple passes on areas of the scene that
will benefi t—such as the aforementioned
fences and vegetation—shifting the sample
location very slightly on each pass. So
even though the object has no true edge, it
will be rendered with fewer jaggies.FONT-TASTIC RESULTS
You don’t need to load a game or rely on
your videocard to experience the effects of
antialiasing. Windows XP offers a font-spe-
cifi c AA technique that applies to the text
that appears in applications such as word
processors and spreadsheets. It’s called
ClearType, and when you turn it on (right-
click your desktop, select Properties, click
the Appearance tab, and then the Effects
button), it will smooth the curved edges
of fonts. It accomplishes this by assign-
ing brightness values to the subpixels that
form each letter. ClearType is turned off by
default; when you turn it on, text should look
less jagged and more pleasing to the eye;
some people, however, conclude that it just
looks more blurry.
While it’s true that antialiasing becomes
more diffi cult to accomplish as more and
more pixels are rendered, it’s also true that
aliasing artifacts become less noticeable as
you increase resolution because each individ-
ual pixel becomes smaller (assuming the size
of your display remains constant). If technolo-
gy ever enables us to render 7680x4800 pix-
els on a 24-inch display, antialiasing just
might be unnecessary.DECEMBER 2006 MAXIMUMPC 65
White Paper: Antialiasing
LOGIC BOARD This
printed circuit board
functions as the interface
between the drive and the
host controller and operat-
ing system.SPINDLE The plat-
ter is mounted to
this shaft, which is
in turn attached to a
tiny motor. The motor
spins the platter like
a record on an old-
school turntable, but
several thousand
times faster (3,600rpm
is typical for a mini
drive).Miniature Hard Drive
The first PC hard drives were 5.25 inches wide, more than four inches tall, and
boasted a whopping 10MB of storage. Today’s mini drives sport several thousand
times the capacity and fit in your shirt pocket.DECEMBER 2006LOGIC BOARD This
printed circuit board
functions as the interface
between the drive and the
host controller and operat-SPINDLE
ter is mounted to
this shaft, which is
in turn attached to a
tiny motor. The motor
spins the platter like
a record on an old-
school turntable, but
several thousand
times faster (3,600rpm
is typical for a mini
drive).Miniature Hard Drive
The first PC hard drives were 5.25 inches wide, more than four inches tall, and
boasted a whopping 10MB of storage. Today’s mini drives sport several thousand
times the capacity and fit in your shirt pocket.1.4"1.65
"ENCLOSURE The drive is
sealed in an airtight enclo-
sure, because an incursion
of the tiniest speck of dust
could destroy the delicate
read/write heads.READ/WRITE HEAD
ASSEMBLY This minute
arm extends over the
spinning platter and rides
a cushion of air while writ-
ing to and reading from
the drive.PLATTER The platter
is a disc of aluminum or
glass that’s been coated
with magnetic particles,
which the read/write heads
arrange to represent data.