Unreal's texture dithering

Went back and checked how the Unreal Engine 1 engines look software rendered and found that it's a pretty interesting topic. I remember they made a big deal of Unreal's software mode at the time because it wasn't gutted of its graphical effects like other 3D accelerated games at the time, like Quake 2. I noticed that the textures in the environment are processed with some type of dithering to "smooth" them out, in a crude type of way. I also managed to disable this in the .ini to see what it looks like without it.

You can compare these two images with and without the dithering, which I took from Unreal Tournament:

Dither on
Dither off

Are there any other games at all (besides Unreal based ones, so no Deus Ex!) that use this?

I recall the dithering being more obvious in Unreal, possibly because I used a lower resolution.

Hard to say... Unreal was pretty unique in its software rendering ability. Most devs wouldn't take the time to hard-code effects like that.

Half-Life had a good software renderer, but it didn't do that.

The only game I can think of with a similar effect is the DOS version of Star Trek: 25th Anniversary, and its sequel. It has a similar effect used to smooth edges on planets seen in space or from the view screen. Here's a pic on Mobygames.

Aliotroph? said:
Half-Life had a good software renderer...

Indeed. It was based on Quake, if you didn't know. As for the original question, I'm pretty sure that I have seen it in games other than Unreal, but I can't remember any specifics, unfortunately.

Am I strange when I would say that I prefer the "un-dithered" graphics?

Olroda said:

Am I strange when I would say that I prefer the "un-dithered" graphics?

No, that texture filter looks like shit. Look at the carpet in GeckoYamori's example screenshots. You can clearly see the yellow border in its design without dithering, and everything generally looks crisp and well defined. In the filtered shot, you lose that detail in the carpet (and any other surface viewed at sharp angles, as floors generally are versus walls) and everything looks like it's made of fuzz.

Games with textures that low res need to be seen with clearly defined pixels. Games like Half-Life look good like that, introduce texture filtering and they start to look like shit. Even standard filtering using some form of linear looks better than attempting to dither it together.

I do think that dithering looks good in the right contexts. It's just that it usually looks best on 2D art in the native raster resolution. Hell, I don't even think it looks that bad as part of the texture itself as long as it's relatively subtle (See Marathon: Durandal and Thief: The Dark Project, though some may disagree with me that these game's textures look good with the kind of dithering they have). It's just that it looks awful when used as a filter during render.

Olroda said:

Am I strange when I would say that I prefer the "un-dithered" graphics?

Having a personal preference is not strange. I just cant stand looking at that blurry dithered blob...
Its as if somebody smeared oil on a lens or something.

Sodaholic said:

Games like Half-Life look good like that, introduce texture filtering and they start to look like shit.

Half-Life looks like butt because its accelerated modes don't support non-power-of-two textures, and the game has a lot of these. They're being scaled down by the engine, making the game look much worse than it should.

Luckily, its software mode is 16-bit, so it retains colored lighting. It also has additional warping effects for liquids.

I remember seeing a third-party Direct-X renderer for Unreal that made the game look way better.

Nomad said:

I remember seeing a third-party Direct-X renderer for Unreal that made the game look way better.

External website said:

Here you can find the special Oldunreal patches like Unreal 227 and updates for the older versions, grafix and sounds, such as OpenGL,
OpenAL and FMOD (OMP) for Unreal / Unrealtournament : http://oldunreal.com/downloads.html

It looks like they try to do bilinear filtering, but because of lack of many colors they dither too?

Meanhwile I remembered a very old article speaking about a technique that might be related. I haven't read it yet but at the end it refers to Unreal.
http://www.hugi.scene.org/online/coding/hugi%2020%20-%20cobil.htm

PrBoom-plus (and possibly normal PrBoom?) has a texture filtering option for Unreal-esque dithering, IIRC.