IDEA: Prerendered background: Styling the black borders

[PurpleHato]

We do know that pre-rendered CG are 4:3 and hardcoded in their size right now. Even if we would remove that limit, we also known that we will to rely on mod to break the monotony of it.
Djipi came of the idea to make a styling that would use a texture, that would then be mirrored on the side to avoid blank black voids, kinda like the NSO feature

I think it would be cool if we could achieve that and maybe propose multiple style
Djipi's Mock-up: