In this screenshot extracted from Portal 1, the scene seems rendered multiple times.
Assuming there is no doubled geometry to fake a render somewhere, I would say there is:
- One render for the player camera.
- One render for the orange portal on the foreground.
- One render for the orange portal on the background.
- One render for the blue portal.
So: 4 renders to composite this shot.
In UE4 terms, you would need 1 main camera and 3 scenecapture2D actors with same resolution or a bit lower.
When you use just 1 scenecapture this way, in UE4, framerate drops.
This game is from 2007 and it supposed to be made with a 3D engine from previous generation, so less performant than UE4.
So: if such a scene need 4 renders, how did they keep it playable?
Did they really use a render each time it seems so or did they combine renders and doubled geometry?
And how would you keep it playable in UE4?