In a 3D first-person / ego perspective game I've got a simple script that checks whether the player is currently located inside of one of a list of specified coordinate boxes (say, in a room of a list of defined rooms), and execute some shader / post process accordingly.
Now what I would need instead is to check whether what the players currently sees is the inside of one of those coordinate boxes, i.e. he might still be outside but on screen sees only the inside of the box, or vice-versa, looks from within the box to the outside.
I could do such a check either by scripting the engine, or in the responsible post process shader.
How would I achieve this? Any suggestions are welcome.