[vtkusers] Re: vtk Flight interactor

[John Biddiscombe]

> John, Is the vtkInteracterStyleFlight broken. I just did a cvs update today and

I've just checked in a fix for the broken Flight style (which has been broken for a couple of months since lots of the interactors
got changed).

I've also added in a whole bunch of code for doing smooth flying with motion damping using a PID (proportional integral
differential) control loop, but I'm not happy with it and it is all commented out. It should fly the same as it used to, but at some
point I'm going to redo lots.

I've added a new option which replaces some unused options from before, it's called RestoreUpVector. When true, the DefaultUpvector
is used to try to realign the flight. If you fly "close to" the horizontal, it will continually adjust your upvector to keep you
flying level, If you fly away from the horizontal, the restoration goes off and comes back on again when you are close to
horizontal. (I've done it like this to prevent weird twisting forces when you are flying at an arbitrary angle).

Lots more work is needed to make things go the wwy I want them

JB
PS. Anyone testing this class, please let me know if the Widgets work properly with it etc. It should conform totally to the
"normal" interactor operation and work, but I await corrections...