simple fog

Hi, I cant find ultra simple fog material in internet wtf, I just need deepth fade fog but also full cube, I mean if I use deepth fade look great outside but when I move camera inside cube is empty. Can you help with this? I dont wanna use volume material becouse this fog moving when i move camera and sry for my bad language

Do you need something like this?

thx but its volumetric and I dont want using this metod

Thnak you so much for this!