Making a camera only see the top 50% of its frustrum

Hi all, i’m fairly new to unity and i’m trying to get a real world projector to exactly map up with the in game camera so I can project onto a 3d scene and have it map exactly with the game camera. The real world projector doesn’t project below itself, so in other words i need the camera to see more like this:

         / sees up here


Solved: I was looking for camera obliqueness. Just in case someone from the future stumbles upon this with a similar problem. Unity - Manual: Using an oblique frustum