From: Simon C Mills (simon++at++wgs.estec.esa.nl)
Date: 04/17/2001 00:36:10
"Arnott, Shane D" wrote:
>
> pfPeople,
>
> Does anyone know a tool that can be used to generate the .star files
> imported by Perfomer?
>
> The only details I can find are what is noted in the Perfomer Importer guide
> "Yale University compact star chart data", but a search at Yeal or on the
> web hasn't turned up much but the 3010.star file that comes with the
> Performer distribution. What I want is a 3010.star but with half as many
> light points.
>
> Anyone know how to cut these files down?
The format is very simple and the source code for the loader comes with
Performer so it's very easy to figure out how you could make your own
program to produce similar files (I have star databases with 100,000
stars derived from ESA's Hipparcos catalogue).
However, to reduce the number of points you don't even need to do that.
Since the stars are listed by brighness, just truncate the file at the
number of stars you want e.g. 1000 and you get that many brightest
stars.
BTW, the .star loader has an artificial brightening factor applied to
all stars which makes more bright stars (looks nice) but which also
makes it more difficult to recognise constellations. I wanted an
accurate representation of the stars so I commented this out and
compiled my own version of the loader. I also converted to use the
currently recommended pfLightPoint API functions.
Hope it helps, Simon
_______________________________________________________________________
Simon Mills
Silicon Worlds S.A.
c/o Modelling & Simulation Section (TOS-EMM) Tel: +31 (0)71 565 3725
European Space Agency (ESA/ESTEC) Fax: +31 (0)71 565 5419
Postbus 299, 2200AG Noordwijk e-mail: simon++at++wgs.estec.esa.nl
The Netherlands http://www.estec.esa.nl/wmwww/EMM
_______________________________________________________________________
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