1 // stars.hxx -- model the stars
3 // Written by Durk Talsma. Originally started October 1997, for distribution
4 // with the FlightGear project. Version 2 was written in August and
5 // September 1998. This code is based upon algorithms and data kindly
6 // provided by Mr. Paul Schlyter. (pausch@saaf.se).
8 // Separated out rendering pieces and converted to ssg by Curt Olson,
11 // This library is free software; you can redistribute it and/or
12 // modify it under the terms of the GNU Library General Public
13 // License as published by the Free Software Foundation; either
14 // version 2 of the License, or (at your option) any later version.
16 // This library is distributed in the hope that it will be useful,
17 // but WITHOUT ANY WARRANTY; without even the implied warranty of
18 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 // Library General Public License for more details.
21 // You should have received a copy of the GNU Library General Public
22 // License along with this library; if not, write to the
23 // Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 // Boston, MA 02111-1307, USA.
29 #ifndef _SG_STARS_HXX_
30 #define _SG_STARS_HXX_
38 ssgTransform *stars_transform;
39 ssgSimpleState *state;
44 int old_phase; // data for optimization
54 // initialize the stars structure
55 ssgBranch *build( int num, sgdVec3 *star_data, double star_dist );
57 // repaint the planet magnitudes based on current value of
58 // sun_angle in degrees relative to verticle (so we can make them
59 // relatively dimmer during dawn and dusk
60 // 0 degrees = high noon
61 // 90 degrees = sun rise/set
62 // 180 degrees = darkest midnight
63 bool repaint( double sun_angle, int num, sgdVec3 *star_data );
65 // reposition the stars for the specified time (GST rotation),
66 // offset by our current position (p) so that it appears fixed at
67 // a great distance from the viewer.
68 bool reposition( sgVec3 p, double angle );
72 #endif // _SG_STARS_HXX_