Fsaa And Anisotropic

DOOManiac

<div class="IPBDescription">I can't tell any difference...</div>I guess I'm still in the Stone Age of visual quality in gaming. To this day I do not use FSAA or Anisotropic whatever it is. Now I know what FSAA is, but WTH is Anisotropic?

And of the screenshots I've seen, I haven't seen it make any difference at all.

Does anybody have any good examples of why I should use either one?

Pulse

You shouldn't. Both tax your video card greatly while providing an almost nonexistant difference in image quality. Anisotropic filtering unless I am remembering incorrectly is just a more advanced version of trilinear filtering, which gives textures a nice smooth look.

Rapier7

DOOManiac... this is how you can tell the difference.

Run a game like CS, make sure there's a large building in plain view. See those jagged edges on its surface?

Now turn up AA and AF, those jagged edges aren't so jagged anymore, are they?

DragonMech

Use google - it will give you an exact definition. But Pulse is right - I prefer a higher resolution over AA or AF.

TheWizard

Anti-aliasing used to be a problem with lower resolutions. at 640x480 those jaggies were REALLY Jaggy.

However with most players now using resolutions above 1024x768, the effects of anti-aliasing are not as apparant as they used to be.

However, the same is not true with anisotropic filtering. The higher the resolution, the more you need Anisotropic filtering. At lower resolutions, textures just don't mean that much. As you increase resolutions, you can pick out the flaws in textures, which is what anisotropic helps smooth over.

<!--QuoteBegin--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> </td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->When a surface has a property of characteristic that is not the same in all directions (for example, woodgrain, tire marks on a runway), anisotropic filtering can be used to blend those features in one direction only (the lengthwise direction, the direction of the grain) so as not to diminish the separation detail.<!--QuoteEnd--></td></tr></table><div class='postcolor'><!--QuoteEEnd-->*from google definition of anisotropic

john_sheu

Playing CS, aliasing is more of a problem (lots of interface between polygons of different colors), but in NS, with a single (and I might add, rather bland) sci-fi color palette (with lots fo bland grays and some brown), it isn't as noticeable. But it still is.

Practically speaking:
A comparison of anti-aliasing and enabled and disabled: (look especially along the edge of the tire as it contrasts against the road surface)
<img src='http://www.tomshardware.com/graphic/20030306/images/iq-fsaa-2.jpg' border='0' alt='user posted image' />

The same for aniso: (look at the guard rail)
<img src='http://www.tomshardware.com/graphic/20030306/images/iq-aniso-1.jpg' border='0' alt='user posted image' />
<b>All pictures credit Tom's Hardware Guide, taken off of article "Strike Force: The new ATI Radeon 9800, 9600 and 9200 Series" of 3/6/03</b>

For NS, I'd say that anisotropic filtering is more important. Because of the drab color of all the walls in most maps, there just isn't that kind of color contrast as you see between the tire and asphalt in the first demo pic, to make you really notice the aliasing.

Talesin

Tom's doesn't allow bandwidth theft, john.

BlackMage

<!--QuoteBegin-Talesin+Apr 15 2004, 10:02 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (Talesin @ Apr 15 2004, 10:02 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> Tom's doesn't allow bandwidth theft, john. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
wint!

basically, antialiasing gets rid of the
===
======

effect and turns it into

===\\\\\
======

wow, my ascii art is horrible

keke, now for aniso.

load hl, without it on, go up against a wall and look down it.
see those lines where the wall gets blurrier?

turn aniso filter on, the blur should:
a) go away
b) blend gradually
c) explode

DOOManiac

As I said in the very first post, I know what FSAA is. My claim was that I couldn't tell a difference.

And I still dunno what Anisotrophic filtering is heh.

Dr_Shaggy

Anisotropic (ahn-eye-so-tro-pik) filtering is for sharpening textures in the distance, especially on surfaces that are almost flat to eye level. A simple example being a flat floor, the textures will become blurry and distorted the farther away they are from the camera (you). This is especially true of FSAA scenes as the anti-aliasing is nice for bluring edge lines, but not textures, so you counter-act that with a little anisotropic filtering. I think john_sheu was trying to post this pic from toms, which shows off the effect nicely, notice the guard rail along the sides of the road (red boxes in the top pic).
Hope that helps Doom.

DOOManiac

oooohh... yeah that makes it a lot clearer. thanks. :)