Clamp pitch values rather than just dumping an error message.

[simgear.git] / simgear / ephemeris / celestialBody.cxx

diff --git a/simgear/ephemeris/celestialBody.cxx b/simgear/ephemeris/celestialBody.cxx
index ae6a792982890b5aa3f22198c109371870adf7b9..2a7f55638974f12129ff552c2c263c67b64ecede 100644 (file)
--- a/simgear/ephemeris/celestialBody.cxx
+++ b/simgear/ephemeris/celestialBody.cxx
@@ -158,22 +158,112 @@ double CelestialBody::sgCalcEccAnom(double M, double e)
   return eccAnom;
 }
 
+/*****************************************************************************
+ * inline CelestialBody::CelestialBody
+ * public constructor for a generic celestialBody object.
+ * initializes the 6 primary orbital elements. The elements are:
+ * N: longitude of the ascending node
+ * i: inclination to the ecliptic
+ * w: argument of perihelion
+ * a: semi-major axis, or mean distance from the sun
+ * e: eccenticity
+ * M: mean anomaly
+ * Each orbital element consists of a constant part and a variable part that 
+ * gradually changes over time. 
+ *
+ * Argumetns:
+ * the 13 arguments to the constructor constitute the first, constant 
+ * ([NiwaeM]f) and the second variable ([NiwaeM]s) part of the orbital 
+ * elements. The 13th argument is the current time. Note that the inclination
+ * is written with a capital (If, Is), because 'if' is a reserved word in the 
+ * C/C++ programming language.
+ ***************************************************************************/ 
+CelestialBody::CelestialBody(double Nf, double Ns,
+                                   double If, double Is,
+                                   double wf, double ws,
+                                   double af, double as,
+                                   double ef, double es,
+                                   double Mf, double Ms, double mjd)
+{
+  NFirst = Nf;     NSec = Ns;
+  iFirst = If;     iSec = Is;
+  wFirst = wf;     wSec = ws;
+  aFirst = af;     aSec = as;
+  eFirst = ef;     eSec = es;
+  MFirst = Mf;     MSec = Ms;
+  updateOrbElements(mjd);
+}
 
+CelestialBody::CelestialBody(double Nf, double Ns,
+                                   double If, double Is,
+                                   double wf, double ws,
+                                   double af, double as,
+                                   double ef, double es,
+                                   double Mf, double Ms)
+{
+  NFirst = Nf;     NSec = Ns;
+  iFirst = If;     iSec = Is;
+  wFirst = wf;     wSec = ws;
+  aFirst = af;     aSec = as;
+  eFirst = ef;     eSec = es;
+  MFirst = Mf;     MSec = Ms;
+}
 
+/****************************************************************************
+ * inline void CelestialBody::updateOrbElements(double mjd)
+ * given the current time, this private member calculates the actual 
+ * orbital elements
+ *
+ * Arguments: double mjd: the current modified julian date:
+ *
+ * return value: none
+ ***************************************************************************/
+void CelestialBody::updateOrbElements(double mjd)
+{
+  double actTime = sgCalcActTime(mjd);
+   M = SGD_DEGREES_TO_RADIANS * (MFirst + (MSec * actTime));
+   w = SGD_DEGREES_TO_RADIANS * (wFirst + (wSec * actTime));
+   N = SGD_DEGREES_TO_RADIANS * (NFirst + (NSec * actTime));
+   i = SGD_DEGREES_TO_RADIANS * (iFirst + (iSec * actTime));
+   e = eFirst + (eSec * actTime);
+   a = aFirst + (aSec * actTime);
+}
 
+/*****************************************************************************
+ * inline double CelestialBody::sgCalcActTime(double mjd)
+ * this private member function returns the offset in days from the epoch for
+ * wich the orbital elements are calculated (Jan, 1st, 2000).
+ * 
+ * Argument: the current time
+ *
+ * return value: the (fractional) number of days until Jan 1, 2000.
+ ****************************************************************************/
+double CelestialBody::sgCalcActTime(double mjd)
+{
+  return (mjd - 36523.5);
+}
 
+/*****************************************************************************
+ * inline void CelestialBody::getPos(double* ra, double* dec)
+ * gives public access to Right Ascension and declination
+ *
+ ****************************************************************************/
+void CelestialBody::getPos(double* ra, double* dec)
+{
+  *ra  = rightAscension;
+  *dec = declination;
+}
 
-
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+/*****************************************************************************
+ * inline void CelestialBody::getPos(double* ra, double* dec, double* magnitude
+ * gives public acces to the current Right ascension, declination, and 
+ * magnitude
+ ****************************************************************************/
+void CelestialBody::getPos(double* ra, double* dec, double* magn)
+{
+  *ra = rightAscension;
+  *dec = declination;
+  *magn = magnitude;
+}