New textured moon and rewritten/restructured Astro code contributed by Durk

Talsma.
2009-09-15 18:31:31 +02:00
parent 38631c9eb3
commit 001a2c89e7
33 changed files with 2142 additions and 1524 deletions
@@ -0,0 +1,90 @@
+/**************************************************************************
+ * star.cxx
+ * Written by Durk Talsma. Originally started October 1997, for distribution  
+ * with the FlightGear project. Version 2 was written in August and 
+ * September 1998. This code is based upon algorithms and data kindly 
+ * provided by Mr. Paul Schlyter. (pausch@saaf.se). 
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id$
+ * (Log is kept at end of this file)
+ **************************************************************************/
+#include "star.hxx"
+
+/*************************************************************************
+ * Star::Star(fgTIME *t)
+ * Public constructor for class Star
+ * Argument: The current time.
+ * the hard coded orbital elements our sun are passed to 
+ * CelestialBody::CelestialBody();
+ * note that the word sun is avoided, in order to prevent some compilation
+ * problems on sun systems 
+ ************************************************************************/
+Star::Star(fgTIME *t) :
+  CelestialBody (0.000000,  0.0000000000,
+		 0.0000,    0.00000,
+		 282.9404,  4.7093500E-5,	
+		 1.0000000, 0.000000,	
+		 0.016709,  -1.151E-9,
+		 356.0470,  0.98560025850, t)
+{
+}
+/*************************************************************************
+ * void Jupiter::updatePosition(fgTIME *t, Star *ourSun)
+ * 
+ * calculates the current position of our sun.
+ *************************************************************************/
+void Star::updatePosition(fgTIME *t)
+{
+  double 
+    actTime, eccAnom, 
+    xv, yv, v, r,
+    xe, ye, ze, ecl;
+
+  updateOrbElements(t);
+  
+  actTime = fgCalcActTime(t);
+  ecl = DEG_TO_RAD * (23.4393 - 3.563E-7 * actTime); // Angle in Radians
+  eccAnom = fgCalcEccAnom(M, e);  // Calculate the eccentric Anomaly (also known as solving Kepler's equation)
+  
+  xv = cos(eccAnom) - e;
+  yv = sqrt (1.0 - e*e) * sin(eccAnom);
+  v = atan2 (yv, xv);                   // the sun's true anomaly
+  r = sqrt (xv*xv + yv*yv);             // and its distance
+
+  longitude = v + w; // the sun's true longitude
+  
+  // convert the sun's true longitude to ecliptic rectangular 
+  // geocentric coordinates (xs, ys)
+  xs = r * cos (longitude);
+  ys = r * sin (longitude);
+
+  // convert ecliptic coordinates to equatorial rectangular
+  // geocentric coordinates
+
+  xe = xs;
+  ye = ys * cos (ecl);
+  ze = ys * sin (ecl);
+
+  // And finally, calculate right ascension and declination
+  rightAscension = atan2 (ye, xe);
+  declination = atan2 (ze, sqrt (xe*xe + ye*ye));
+}
+  
+
+  
+  
+