I would say that yes, my problems requires angles. I'm sure there's a better way to do all of this, but if someone can help me with the conversion I'm looking for, then at least I know I'll be able to get this feature to my game. Definitely not in the best possible way, but in a way that works for me.
I'm essentially a self-learned rogue programmer, so ultimately I only care about getting things to work, no matter how ugly the code is. I'm also at the moment 100% focused on actually coding my game, so learning new stuff that takes a while to swallow is not in the cards for me right now.
I will definitely later look at some line of sight and field of vision tutorials that were already recommended to me, but now I'd just like to get that one function that does the conversion for me. But naturally I welcome all extra tips that you can give me.