Texture filtering?

Ceano · Post by **Ceano** » 01 Feb 2006, 13:26

The second down from the top option in advance settings "Texture filtering" what does that rely do?

LuminaryJanitor · Post by **LuminaryJanitor** » 02 Feb 2006, 02:46

As far as I know, texture filtering serves two purposes.

A texture is an array of discrete pixels, and a texture filter smooths it out (so it looks more like an actual image, and less like a bunch of coloured squares).

Unfiltered vs Bilinear filtering

Second, texture filters remove some of the distortion seen when viewing textures from an angle or from a distance. Better filters produce better results
(ie Bilinear < Trilinear < Anisotropic 2x < 4x ...).
Be sure to click on the image below - the difference isn't really visible in the thumbnail.

Trilinear vs Anisotropic filtering

Ceano · Post by **Ceano** » 02 Feb 2006, 10:30

OK thanks

sigsegv · Post by **sigsegv** » 03 Feb 2006, 09:31

LuminaryJanitor wrote: Second, texture filters remove some of the distortion seen when viewing textures from an angle or from a distance. Better filters produce better results
(ie Bilinear < Trilinear < Anisotropic 2x < 4x ...).

Actually, I think that Trilinear < Bilinear. Anisotropic is best, indeed. Bilinear produces images with higher quality and higher stress for the gfx card. Trilinear is faster and get lower quality image.

Ceano · Post by **Ceano** » 03 Feb 2006, 12:14

I have a ASUS GeForce 7800GTX so i always go for the best image quality

LuminaryJanitor · Post by **LuminaryJanitor** » 03 Feb 2006, 18:30

sigsegv wrote:Actually, I think that Trilinear < Bilinear. Anisotropic is best, indeed. Bilinear produces images with higher quality and higher stress for the gfx card. Trilinear is faster and get lower quality image.

Sorry, but... no. The difference may not be obvious, but trilinear definitely looks better. There's not much difference looking straight-on and close up, but from an angle or a distance, bilinear distorts the textures pretty badly. Repeat that runway comparison above (ie compare bilinear vs trilinear on an angle) and you'll see what I mean.

Trilinear filtering is also more work for your GPU - "Bilinear" refers to interpolation along two lines, while "Trilinear" refers to interpolation along three lines. Though considering that a TNT2 could pull off trilinear filtering without a problem, I think that these days both are pretty insignificant. I get the feeling that anisotropic filtering is much more work for your video card (though I don't know much about it, other than that "an" (not) - "iso" (same) - "tropic" (direction) roughly translates to "not the same in every direction". Sounds pretty complicated

.

Koffy · Post by **Koffy** » 04 Feb 2006, 03:06

No, anisotropic filtering does not produce *much* stress on video cards, at least the newer ones. I will probabli lover your framerate by 2-5 fps, not much actually.

LuminaryJanitor · Post by **LuminaryJanitor** » 04 Feb 2006, 03:22

I didn't say AF was a lot of stress, I just said much more than bilinear or trilinear filtering.

A 5 fps difference on a modern card would probably be a 50 fps difference on a TNT2 - that is, it just couldn't handle AF. But it could handle trilinear filtering without a problem, so I figured trilinear must be much less work than anisotropic.

Koffy · Post by **Koffy** » 04 Feb 2006, 16:11

I know, but you sayd

I get the feeling that anisotropic filtering is much more work for your video card

I just wanted to make clear, that for moder cards it is not that much work. So that people dont get scared about AF.

LuminaryJanitor · Post by **LuminaryJanitor** » 05 Feb 2006, 16:10

I did a little bit of research on this (by which I mean I read the Wikipedia article...) and it looks like AF is more of a performance hit that I thought - trilinear --> 16x anisotropic gives a 20 fps decrease in CS:S (http://mirror.garry.tv/img/cssource/tex ... tering.jpg).

This is apparently because it uses a ridiculous amount of memory. Each sample taken is four bytes, so each pixel in 16 sample AF takes up 64 bytes. 1280x960 resolution = 1,228,800 pixels, so 16xAF requires 75MB of texture memory per frame, which works out to about 5GB per second (assuming you can actually get it running at 60fps

).

Jmac- · Post by **Jmac-** » 06 Feb 2006, 18:40

I have absolutely no problem running 16x AF and 2x AA @ 1024x768x32 in CS:S on most maps with my 6600GT and it's being bottlenecked by my CPU (AMD Athlon 2500+) ... Right now, the only maps I can think of that I turn AA off on are Aztec and Inferno. I can't play well when my FPS drops down into the 30s, unfortunately.

If I had a better CPU, it would be all maps (I put my 6600GT into a system with a AMD Athlon64 3000+ and it performed a lot better).

LuminaryJanitor · Post by **LuminaryJanitor** » 07 Feb 2006, 02:30

Just my opinion, but I reckon you're much better off turning AF down a few notches and cranking your resolution up to 1280x960. Even if I have to turn of AA as well, I feel that it's worth it. At 1024x768, you can't even see most of the detail that goes into games these days.

Jmac- · Post by **Jmac-** » 07 Feb 2006, 02:34

My monitor is from 1994 and only capable of 1024x768

I've been waiting for it to die for like 5 years now so I can go get a new one, but it just won't ... Suprisingly, there's still not a single thing wrong with it other than it's about 3 feet deep and draws a whopping 2.6 amperes (312 watts @ 120 volts) ...

LuminaryJanitor · Post by **LuminaryJanitor** » 07 Feb 2006, 06:56

Wow... I'm amazed it's still going after 12 years. Most things these days aren't designed to last any longer than their warranty.

If you really want it broken though, I'd be happy to help you out

.