How to make "screens" that you could see npc:s or other players fighting? And how is it possible to change view? Some screens in HL2 singleplayer change view when u press "use".
And is it possible to make mirrors, that when you walk in front of it, you could see youurself (surprise!!).
And is it possible to make mirrors, that when you walk in front of it, you could see youurself (surprise!!).