Camera backbuffer

Is it possible to copy the Backbuffer (or Frontbuffer) of the Maincamera to a texture ?
I want make a backward-replay function of the latest 2 seconds of the game.

the recording of the positions is not the best way, because I can’t copy the positions of the particles and on iPhone maybe I get less frames if I have a lot of gameobjects.

My customer want replay exact the same scene including particle effects.

Any Idea how to make this ?

Texture2D has a function called ReadPixels that reads an area of screen into a texture. Speed may be an issue if you are recording gameplay live as a “video”, though.

Sorry for the resurrection here… but I would like to know if there is anything faster? In other words, is there something that is faster at getting the screen pixels?