[Plasma]

How can I obtain the user's positional data in the virtual environment?

Specifically, I am designing an experiment in which the user will move down a main hallway and then turn right down one of two hallways that lead off it. Proceeding down the second hall, they will see a symbol on the wall and will then return to the starting position. Once at the starting position, they will orient themselves so that they are pointing to the now occluded symbol. (Hopefully this makes sense).

Ideally, the user will use a crosshair to point to the symbol.

I have two questions:

First, is it possible to have a crosshair on the screen at all times (think Quake, or similar).

Second, how do I obtain the user's positional information once they are in position? All I need is rotational information about the Z-Axis (yaw, I think) to see how close the user is to actually pointing to the symbol.

Thanks!