How can I create a mirror material for the game engine? A google search found this demo of a mirror in the BGE Video:Mirror Made in Blender Game Engine but I can't find out how to setup the material. Unlike in the BI renderer the option Mirror isn't available when in BGE.

What tricks do I need to know?
It is possible by using bge.texture.ImageMirror.
Basically the mirror objects texture is frame by frame replaced with a video-texture which is captured by another camera.



A tutorial and an example .blend file which works with Blender 2.68.