[chimera-dev] Camera changes in chimera 1.2348

[Greg Couch]

There used to be three attributes, given in the same units (only ratios 
where used), eyeSeparation, viewDistance (distance to the screen), and 
screenWidth (the idea was to scale it to the actual window width, but that 
was never done).  The default values were given in inches: 2.0, 30.0, and 
and 13.0, respectively.  The effective field of view was just under 25 
degrees.

Now, there is an explicit fieldOfView attribute, because chimera maintains 
the field of view when resizing the graphics window.  Of the original 
three attributes, only eyeSeparation remains, and it is given in 
millimeters, and the latter two are replaced with screenDistance and 
windowWidth.  The windowWidth value is automatically computed when the 
graphics window is resized which in turn adjusts the screenDistance based 
on the field of view.  If the screenDistance is explicitly set, then the 
field of view angle is recomputed.  Defaults for the new values, are 50.8 
mm for the eyeSeparation, and 25 degrees for the fieldOfView.

 	- Greg