Vertically wrapping skies?

Are you searching for skyboxes by any chance?

Afaik, you need to have a sky that is 256x256 (or maybe 256x240, I dunno) at the least(although 1024x256 is usually better). If you check closely in ancient aliens (the wad you used as an example), most sky textures are in 1024x240 dimensions I think instead of your usual 1024x128. 

14 minutes ago, Yugiboy85 said:

Afaik, you need to have a sky that is 256x256 (or maybe 256x240, I dunno) at the least(although 1024x256 is usually better). If you check closely in ancient aliens (the wad you used as an example), most sky textures are in 1024x240 dimensions I think instead of your usual 1024x128. 

Yeah that's the thing, when i try with a 1024x240 big sky image it still doesn't wrap properly, like in this image below, this 'earth' part of the sky is supposed to be the very top of the sky but it's not tiling correctly at all which is what is so confusing...

Leodoom no, this is for a boom wad like i said.

Do you have "strech skies" enabled by any chance? 

Afaik, a sky of this dimension (1024x240) works alright in prboom+ 

Then again, I'm not that big of help when it comes to technical stuff regarding sky textures and stuff heh. Especially tiling. But from the looks of it, it seems as though you have the "strech skies" enabled. 

Yeah it works just fine in PRBoom+ but it won't display correctly in GZDoom (and the AA skies do just fine...). I tried changing the sky stretching setting but it didn't appear to do anything (even after restarting). Confusing.

Tall skies should not be stretched in ZDoom.

Note that you can always use something like a TEXTURES lump to redefine the sky texture to make it even taller, since it wraps vertically. Tile it in the texture editor so that it's 1024x512.

Also note that the OpenGL renderer in GZDoom uses a spherical projection with fading to a single color at the top and bottom. In GZDoom's software renderer, it is also possible to have that "capped" sky, depending on user settings.