How to make a mirror in the editor??

[Traggey]

Even if you could see the player (most games neglect to have player models visible in first person beyond their arms), mirrors are very impractical in games. The cost of redrawing or computing what part of a scene is visible in a mirror would make frametimes so high they would get arrested for drug abuse. To emulate one you'd have to carefully build the environment around the "mirror" and get a custom-made player model. Probably way more work than it's worth.

What about taking a screenshot of the environment and using it as a texture for reflection, and only letting the mirror mirror the player and other moving objects? (in case you havent realised we are now in the part of discussion where its no longer in amnesia)

Mirrors in game engines are done with cubemaps, cubemaps don't work that way. Either you mirror the entire thing, or you don't.

A low-res real time cubemap isn't too expensive, but you really don't want to use it in an area where ''action'' will go down.

And when I say low res, I mean 64 x 64, anything above that will have quite the impact.