I found one reference here: https://www.doomworld.com/forum/topic/103245-question-about-the-trigonometry-in-the-doom-source/ https://www.doomworld.com/forum/top

I found one reference here: https://www.doomworld.com/forum/topic/103245-question-about-the-trigonometry-in-the-doom-source/ https://www.doomworld.com/forum/topic/103245-question-about-...