fly/flightgear
1
0
Fork 0
Code Activity

Ephemeris: Exposure of the moon's absolute attributes in the property tree.

Browse source 
This includes the moon's absolute position, age and phase.  For this, the new
simgear MoonPos::get*() functions are tied to the property tree at
"/ephemeris/moon/" using a new tieMoonPos() function.

In addition the moon illumination factor is exposed by tying the simgear
MoonPos::getIlluminanceFactor() function to the /environment/moonlight property.
This is a number ranging between 0 and 1 based on the log of the illuminance of
the moon outside the atmosphere.  It is calculated as

    factor = (log(I) - max_loglux) / (max_loglux - min_loglux) + 1.0,

The illuminance of the moon outside the atmosphere, I, is from equation 20 from:

   Krisciunas K. and Schaefer B.E. (1991). A model of the brightness of
moonlight, Publ. Astron.  Soc. Pacif. 103(667), 1033-1039 (DOI:
http://dx.doi.org/10.1086/132921).

For more background, see
http://forum.flightgear.org/viewtopic.php?f=47&t=28201&start=60#p270516 .
This commit is contained in:
Edward d'Auvergne 2015-12-13 16:21:02 +01:00
parent 6e62228c1d
commit b574728411
1 changed files with 14 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
src/Environment/ephemeris.cxx
View file

@ -33,6 +33,11 @@ static void tieStar(const char* prop, Star* s, double (Star::*getter)() const)
fgGetNode(prop, true)->tie(SGRawValueMethods<Star, double>(*s, getter, NULL));
}
static void tieMoonPos(const char* prop, MoonPos* s, double (MoonPos::*getter)() const)
{
fgGetNode(prop, true)->tie(SGRawValueMethods<MoonPos, double>(*s, getter, NULL));
}
Ephemeris::Ephemeris() :
_impl(NULL),
_latProp(NULL)
@ -60,6 +65,15 @@ void Ephemeris::init()
tieStar("/ephemeris/sun/ye", _impl->get_sun(), &Star::getye);
tieStar("/ephemeris/sun/lat-deg", _impl->get_sun(), &Star::getLat);
tieMoonPos("/ephemeris/moon/xg", _impl->get_moon(), &MoonPos::getxg);
tieMoonPos("/ephemeris/moon/yg", _impl->get_moon(), &MoonPos::getyg);
tieMoonPos("/ephemeris/moon/ze", _impl->get_moon(), &MoonPos::getze);
tieMoonPos("/ephemeris/moon/ye", _impl->get_moon(), &MoonPos::getye);
tieMoonPos("/ephemeris/moon/lat-deg", _impl->get_moon(), &MoonPos::getLat);
tieMoonPos("/ephemeris/moon/age", _impl->get_moon(), &MoonPos::getAge);
tieMoonPos("/ephemeris/moon/phase", _impl->get_moon(), &MoonPos::getPhase);
tieMoonPos("/environment/moonlight", _impl->get_moon(), &MoonPos::getIlluminanceFactor);
_latProp = fgGetNode("/position/latitude-deg", true);
update(0.0);