Irregular texture resolution/less restrictive resolution

[Markelius]

So while I realize OpenMw is still a game engine, and probably won't support textures at irregular resolutions like 500x350 and such, it would still be nice to have some more flexibility than Morrowind's engine gave.

IIRC, Morrowind's engine would only accept textures that were a power of two, so 8,16,32,64,128,256,512,1024,2048,4096,8192,ect. In Skyrim, I'm pretty sure the engine would accept resolutions which were in between those that I listed, such as 1536. If such resolutions were accepted in Morrowind, it would be very helpful for modding as irregularly proportioned images would not need to be resized to a restrictive, more square resolution.

That being said, what are the restrictions right now?

[Chris]

IIRC, Morrowind's engine would only accept textures that were a power of two, so 8,16,32,64,128,256,512,1024,2048,4096,8192,ect. In Skyrim, I'm pretty sure the engine would accept resolutions which were in between those that I listed, such as 1536.

OpenMW should accept any texture resolution that the hardware supports. Any non-ancient hardware should support non-power-of-two textures, so they should already work. However, be aware that non-power-of-two texture sizes aren't efficient on GPUs, particularly with wrapped or mirrored modes, so using it in many places will hurt performance. In addition, DXT compression (something textures usually use) works in 4x4 blocks, so if you have a texture width or height that's not a multiple of 4, the texture is going to contain junk pixel data for them regardless (they just won't be shown).

[Tes96]

IIRC, Morrowind's engine would only accept textures that were a power of two, so 8,16,32,64,128,256,512,1024,2048,4096,8192,ect. In Skyrim, I'm pretty sure the engine would accept resolutions which were in between those that I listed, such as 1536.

OpenMW should accept any texture resolution that the hardware supports. Any non-ancient hardware should support non-power-of-two textures, so they should already work. However, be aware that non-power-of-two texture sizes aren't efficient on GPUs, particularly with wrapped or mirrored modes, so using it in many places will hurt performance. In addition, DXT compression (something textures usually use) works in 4x4 blocks, so if you have a texture width or height that's not a multiple of 4, the texture is going to contain junk pixel data for them regardless (they just won't be shown).

Even using triple SLI GeForce GTX 880 cards, performance would still be hurt?

[SquireNed]

Yes. It has to do with the ways they are processed; computers are at their most efficient in powers of two because of the binary system that powers them; if you're working with something smaller than a power of two it still hurts.When you deal with textures in memory, this is the most efficient method to do so.

Now, the question you're asking is somewhat different. If you're still doing something noticeably suboptimal, and if you're justifying it by saying that it won't matter on three-thousand dollars of computer you're probably taking the wrong approach to it. There's generally little harm in just sucking it up and either cutting your texture down to a power of two or upgrading it to the next greatest power of two. Sure on a massive SLI rig you may be able to enjoy horrible optimization (actually, doing stuff like that would be one of the things that really impacts SLI efficiency) and still chug along at 120fps or whatever the kids do these days, but there will still be a (potentially negligible) impact. Keep in mind that the 880 runs at about 22 times the speed of my current card, which is not exactly a wimp, and when you're dealing with a PC architecture it's important to consider the fact that not everyone will be using cutting-edge hardware.

[SGMonkey]

I don't know of a game that allows for non-power-of-two textures. I can't imagine Skyrim does either.

I don't really see a need for this.

[SquireNed]

Not only is there not a need (any such work should be done by the texture artist, if for no other reason than to stay in practice), it's entirely undesirable to encourage such behavior.