[vtkusers] a bug in vtkFollower

[David Gobbi]

On Wed, 6 Jun 2001, Matjaz Subelj wrote:

> >From the [vtkFollower] changelog (diff to previous 1.32):
>
> "ENH: now vtkFollower exhibits special behavior for ParallelProjection
>      (i.e. follows VPN instead of actor -> camera vec if
> ParallelProjection)"
>
> This is okay if it would be true. It follows DOP instead. Since DOP =
> -VPN
> the actor gets mirrored (Direction Of Projection vs. View Plane Normal).

This is fixed now.  The actor follows the -DOP for ParallelProjection.
Actually following the VPN is incorrect because if the camera view is
sheared (via SetObliqueAngles) then VPN != -DOP.

 - David