Moving the observer around evolving snapshots
---------------------------------------------

In this exemple, the track followed by the camera is set using glups.
First, lunch glups to visualize one snapshot :

# glups ../data/treo4000.000.gad

Set the desired view, and then, in the menu, set 
Menu >> GL Mode >> Auto-motion on

You can now guide the motion of the ovserver using the mouse and the + and - keys.
Record the track by pressing the F1 key. Once you have finished, press
again the F1 key. You can now quit glups. 

A direcory named track, containing a record of the track followed by
the observed has been created. 
We must now interpolated these files in as a function of the desired frame
needed for the movies. This is achived by the command :


../bin/gsplinetrk -n 400 track/*.trk --dirname=newtrack00 --basename=trk 

A new directory "newtrack00" containing the new 200 interpolated track files 
is created. 
These files must now be converted into pNbody parameter files :

../bin/gtrk2nbd newtrack00/*.trk  --eye='both'    --snapfiles="../data/treo*.gad"

Two directory "right" and "left" are created with the corresponding files.

If you need only one eye, simply type :
../bin/gtrk2nbd newtrack00/*.trk  --eye='default'    --snapfiles="../data/treo4000.000.gad"

The files are then stored in a directory called "center".

Now, it is time to setup the movie parameter file "filmparameter.py".
The movie is composed of 2 horizontal sub-movies, one for each eye.
The position of the observer corresponding to each eye, 
is now defind entirely by the files stored in the "right" and "left" directories. 
(param[1]['tdir'] = 'right',param[2]['tdir'] = 'left').
The other parameters may be chosen freely.


mkgmov -p filmparam.py movie04.gmv ../data/treo*
gmov -s 50 movie04.gmv  





