A want mention another topic: 360° SkySphere for Mappers
However there exists some problems, with use single Equirectangular projection texture for skybox.
Equirectangular projection must be in ratio 2:1. So you limited to 4096 on biggest side.
This also can cause troubles for users, which limited in maximal resolution. They will load mimaped version of it, and it goes be worse from cube skybox.
And spheres itself is complicated BSP which can affect other map, add here cuts or BSP bugs.
Sky cube is more convenient solution for this.
For get sky cube from your Equirectangular projection you can use service: Panorama to Cubemap
After you done, resize your cube side textures to size which be power of 2. Like 256, 512, 1024, 2048, 4096. And use on your map.
For skybox best if set bUnlit and bNoSmooth. Last one prevent make cube edges visible. Or at least make it less visible.
There example of it. It use 1024 size of sky box. Also it use BC2 compressed mipmaps, for preserve full colors.
Example based on examples from topic above.
This example use 6 textures of 1024x1024 each.
When original use one texture 4096x2048.
So there still possible use textures of 4096x4096 size for cube, if you want x4 more details.
As source for Equirectangular projection (360 view), can be used AI generated skybox from https://skybox.blockadelabs.com/
How to make Skybox (Cube) from 360 panorama view
Re: How to make Skybox (Cube) from 360 panorama view
https://matheowis.github.io/HDRI-to-CubeMap/
This is another great alternative, which I use sometimes.
This is another great alternative, which I use sometimes.
