Cipheron on 5/3/2023 at 08:24

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If you downscale the image outside the game then the game is going to have to upscale it itself to display it, so the end result will entirely depend on which upscale filter the game is using.

For that generic resizing software, you probably got artifacts because for a texture, it's gotta join on the edges, but the software doesn't know that, so it's not correctly oversampling across the edges.

When you downscale, you need to sample a region of the texture, and generate an average color. For a texture that has wrap-around, you'd need to sample across the edges. One way to trick it into working would be to make a slightly bigger image, with parts of the edges added on. Then, you downscale that, and then crop back out the unneeded parts. That way, the image would have the correct sampling across the edges.

Cipheron on 5/3/2023 at 13:36

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... ?

HD textures contain more data, that's why they're HD.

The point is that say the original game used 256x256 textures, then you can replace those with 512x512 textures or 1024x1024 textures. So of course ... this is going to wreck low-end hardware. That's kind of the point here: to take advantage of high-end hardware better.

If they make a "HD texture pack" that runs fine on weak hardware: they messed up, because they didn't make something that would take advantage of the new hardware, and they could by definition crank up the detail even higher then.

If you want to run it on weak hardware: don't get upscaled textures.

baeuchlein on 6/3/2023 at 22:42

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HD textures contain more data than low-res ones. If one goes from 256x256 pixel textures to 1024x1024 ones, the hardware and software has to deal with 16 times the amount of data used for the smaller textures. And some people even use 2048x2048 textures in Thief, AFAIK - 64 times more data than the 256x256 ones.

Imagine you drink one can of beer, coke or whatever you like. Now, imagine someone forces you to drink 64 cans instead, and in the amount of time you'd usually need to swallow just one of the cans. Could be a bit too much, right?

There are some possibilities to reduce the impact of large textures on hardware. One can resize the textures, such as from 2048x2048 to 512x512, which might yield something that does not look as good as the 2048x2048 ones, but still better than 256x256 ones. But it is not guaranteed that all this goes so well. This is why programs may rescale textures, but can't really tell whether the result looks good or rather resembles the effect of eating the textures and vomiting them out again. Usually, a human has to look over the results in order to tell which ones are acceptable and which ones are not. Some similar discussions happened when Soul Tear recently used a program to make hi-res textures from smaller ones - frequently, people said that the result looked too good, too clean. Others found it great.

Another option would be to compress textures, which is not the same as resizing them. Compression means that a program tries to squeeze the data while preserving much of the original detail. Lossless compression would even mean no loss of detail while the data would still shrink. But there are limits to that as well as the other way (compression with loss). What people think of that may differ widely - there was an experiment done by a german computer magazine about 25 years ago dealing with how well one could hear the differences between non-compressed CD music and its MP3 compressed counterpart, with various compression rates. Turned out that people with impaired hearing could better say which ones were MP3 and which ones were original (uncompressed). Reason is that MP3 is a lossy compression made for standard hearing.

As one can see, there are already several factors influencing how compressed and/or reized textures may look, and how much load these place on the hardware processing it. And we have not even dealt with the software yet, which does not only consist of the Thief game, but also the video drivers which are driving the hardware and "feed" the texture data to the video card, and furthermore the Windows and DirectX versions.

If someone has problems with a texture pack, one should first try playing without that pack. Believe me, the world will not end because of this. It may not even look much uglier than before. If, on the other hand, someone does want a texture pack to be optimized, then the chances of getting it optimized without thinking about that are small. Neither will the pack authors usually make one hundred of custom versions for one or two hundred players, nor will there be a program to which the user can blindly feed all the existing textures, and get perfect-sized and perfect-looking results out of that process. It is simply too complicated for that. Maybe this will be possible in ten or twenty years, but not today.

So, everyone wishing to strike a better balance between texture size (or texture impact on one's own computer system) and texture looks will most likely have to do it mainly by himself. And if that leads to much labour for little effect (as I experienced while trying to shrink some very large textures in some Thief FMs), then one may finally understand why most people making texture packs and the like don't prepare versions for low-end machines: Much ado about almost nothing.

And of course, not every lag the player sees is a result of textures being too big. There's much, much more that can cause lags.

Therefore, my solution for optimizing textures in games is... none at all. Only in very, very rare cases did I ever see any result of trying to change textures in order to improve performance.