Joe said:
I know what AA stands for but I don't actually know what it and anisotropy
does. Can someone explain what they mean in detail and how it affects
various games (say like NeverWinter Nights)? Thanks.
AA is antialiasing. Aliasing is the pixelation you get - jaggies. You
notice them most when you get high contrast edges, especially when the angle
(of a straight edge) is close to horizontal or vertical, but not quite.
What AA does is calculate how much of the pixel is on the left hand side of
the line (considered by looking along the direction of the line, if you
will) and how much is on the right hand side. What it then does is create a
pixel which is some combination of the two colours it should be. This has
the tendancy to smooth the adges, eliminating jaggies. There are several
formulas for calculating this, some more accurate than others, but the more
accurate ones are usually far greater computationally.
AF is anisotropic filtering. It is a step up from trilinear and bilinear
filtering, which are isotropic filtering techniques. These filtering
techniques are used to map textures onto surfaces that appear at an angle to
the camera (rather than square-on). Basically the end result is that
tectures are "more correct" - things like text mapped onto a surface will
appear much sharper with AF.
There should be plenty of very detailed descriptions of the above techniques
on many good 3d card review sites, and if you want the maths and theory in
detail then I suggest looking for books on computer graphics or searching
for papers on the matter.
Ben
