My goal is to create a realistic reproduction of a projector mounted on the ceiling. So far I can reproduce a projector that is projecting straight. But I cannot wrap my head around how to correct perspective distortion when the projector is tilted down.
Edit: The Solution shoud work like you woud expect from a real world projector. With the light beam originating from the lamp position spreading out onto the surface and interacting with objects in between.
This example file: