I'm trying to implement some portals in my game using Sebastian Lague and DigiDigger videos as reference, but after struggling with the part of aligning the camera with the player and cutting the viewport texture to give depth, all I can do is show a static print of the other side.
Some days later I found that frustrum culling can make things easier (Like this), however they didn't say how did this work or is implemented to make it look like a window, any help with creating a simple portal view is appreciated.
Thanks in advance!