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Well as we all know, the jagged
edges of a heavily aliased scene, certainly do take away
from the realism of any 3D image. The GeForce4 was
targeted to breath new life into real-time Anti-Aliasing and
NVIDIA believes you shouldn't have to turn it off in order
to have acceptable frame rates for certain games.
We'll take a look at NVIDIA's Accuview next.
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GeForce4 Accuview Anti-aliasing |
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Getting rid of the
"jaggies" while sustaining great frame rate -
"Just leave it on" |
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With the GeForce
4 and GeForce 4MX, NVIDIA has incorporated more efficient,
patent pending, Anti-aliasing logic which they have dubbed
"Accuview AA". Prior to the release of the GeForce 3,
NVIDIA used super-sampling to help remove the "jaggies" from
an image. To put things simply, what super-sampling
does is render a given frame at a higher resolution, 2X or
4X the native resolution for example. Then, from the
higher resolution frame, color samples are taken from around
each pixel, the colors are blended together and then that
frame is scaled back down to the native resolution. Because
the original frame is rendered multiple times,
super-sampling requires large amounts of memory bandwidth
and fill-rate to handle all of the duplicate texture and
vertex data. So while visually, super-sampling AA does
produce excellent images, the performance hit is substantial
and not feasible on most GPUs at any native resolution over
800x600. This is why NVIDIA incorporated logic into
the GeForce 3 to perform a different AA method known as
multisampling.
Vastly simplified, multisampling works in a similar fashion
to super-sampling, but due to the "features" incorporated
into the GPU, the original texture data is not sent through
the pipeline multiple times. Because the texture data
is reused, far less memory bandwidth is required to enable
Anti-aliasing. The existing texture data is used to
take color samples from "virtual pixels" surrounding the
original pixel, and then all of the color samples are
blended together. Multisampling has a few side effects
though. Since less bandwidth is required, performance
is increased but at the expense of image quality. When
using multisampling, because the texture color data is
reused, textures generally get blurred. To combat this
blurring effect, a variety of techniques can be used, like
Anisotropic filtering, or changing the location of the
"virtual pixels" used for the color samples.
Depending on which AA mode is chosen, Accuview AA uses both
of these methods to increase visual quality, and due to
architectural optimizations, performance is increased as
well. NVIDIA claims the GeForce 4 can do AA twice as
fast as the GeForce 3, because the architectural
enhancements save an entire frame buffer write. A new
AA mode, "4xs", has also been introduced which uses new
sample positions and texture sharpening for a new level of
AA quality previously unavailable on other cards.
Let's have a
look at some in game shots at the various settings.
GeForce4 Ti 4600
and GeForce4 MX 460 Benchmark and Performance Update
2/10/02
Accuview in Action - Novalogic's Comanche 4:
Alright, I'll
admit it. Not everyone is a Flight Sim or Combat
Flight Sim fan. However, in the age of the "first
person shooter", I felt compelled to give you eye candy from
behind something a little more interesting that a rocket
launcher or rail gun. Not that you could fall asleep
with either of those but you get my drift. So we took
to the skies with
Novalogic's great looking new Combat Chopper Sim, Comanche
4. This game looks fantastic and is a blast to
play. It is a DirectX 8 title with full support for
vertex and pixel shaders.
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2X AA
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Quincunx AA
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4X AA
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4XS
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Eye
Candy 1
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Eye
Candy 2
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Eye
Candy 3
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First some
observations... We had a bear of a time getting screenshots
with Hypersnap, our usual method. When in AA mode, it
just kept grabbing captures of an entirely different screen
in the game than we were trying to capture at the time.
So, we had to trust the built in screen capture capabilities
of Comanche 4. Frankly, we're waiting to hear back
from NV and Novalogic as to whether or not the above
screenshots are representative of the AA settings they were
taken in. However, take a look at the 2X shot, it
still has a fair amount of jaggies going on. We took
all shots at a 1024X768 resolution. Then compare
Quincunx mode versus 4X and 4XS mode. You will notice
that the textures for the ground look a lot better in 4XS
mode versus Quincunx and even slightly better than 4X mode.
Versus 4X mode, the effect is very subtle however.
Regardless, on the GeForce4 Ti 4600, this game is simply
amazing and with full 4X AA, totally smooth. The rest
of the shots were taken with 4X AA and are there for just
gazing at. Very nice indeed.
Alright then, I
think we've covered most of the new features and salient
points of NVIDIA's new GeForce4 architecture. Let's
have a look at the drivers and a few initial tests.
The
benchmarks are next!
New
Detonator 27.30 Drivers and Quake 3 Scores |