Functions via camera rotations...

What is the simplest way to implement a function that is executed when the camera rotates to a specific point? Can this be done in a way, either than OnMouseEnter, like in horror games, where you look one way then back to find that something changed?

Please, I am not asking for a script, just the way I should structure it and how I would do it.

Thanks in advance!

What I do is cast a ray from the center of the camera out along it’s local forward vector and then “monitor” it (you could also cast a line if you want a specific distance). I then place an invisible trigger where I want the look target to be and execute the method once the ray/line comes in contact with the trigger.