There are indeed precomputed LUTs, but apparently you need to be a bit more sophisticated than that if you want your sun angle to be dynamic, and they also did

There are indeed precomputed LUTs, but apparently you need to be a bit more sophisticated than that if you want your sun angle to be dynamic, and they also did clouds: https://www.ea.com/news/physically-based-sky-atmosphere-and-cloud-rendering https://www.ea.com/news/physically-based-sky-atmosphere-and-....