obj graphics fly-thru help

[Rick Towler <rtowler(at)u.washington.edu>]

This is a second cry for help.

I am trying to develop a set of algorithms that will allow me to
"fly/walk thru" a 3d scene.  Via keyboard events I translate the op
model in the XZ plane (forward/back and slide left/right).  This is easy
enough.

What I would like to do is us the mouse to adjust pitch and yaw of the
viewer (look up/down and left/right).  So far my attempts have been less
than perfect.  As I understand it, the solution is to change the point
of rotation of the Top Model from 0,0,0 to the "eye" of the viewer. 
Basic trig.  But this isn't yielding the expected results.  My guess is
that I am not understanding the entire problem.

Has anybody done anything like this?  Do you have any tips?

Thanks.

-Rick Towler