const osg::Matrixf Astronomy::equToHorTransform(
const t_aTime &aTime
, const float latitude
, const float longitude) const
{
const t_julianDay T(jCenturiesSinceSE(jd(aTime)));
const float s = siderealTime(aTime);
return osg::Matrixf::scale(-1, 1, 1)
* osg::Matrixf::rotate( _rad(latitude) - _PI_2, 1, 0, 0)
* osg::Matrixf::rotate(-_rad(s + longitude) , 0, 0, 1)
// precession as suggested in (Jensen et al. 2001)
* osg::Matrixf::rotate( 0.01118 * T, 0, 0, 1)
* osg::Matrixf::rotate(-0.00972 * T, 1, 0, 0)
* osg::Matrixf::rotate( 0.01118 * T, 0, 0, 1);
}
void StarsGeode::update(const Himmel &himmel)
{
// TODO: starmap and planets also require this ... - find better place
const float fov = himmel.getCameraFovHint();
const float height = himmel.getViewSizeHeightHint();
//u_q->set(static_cast<float>(tan(_rad(fov / 2)) / (height * 0.5)));
u_q->set(static_cast<float>(4.0 * tan(_rad(fov * 0.5)) / height));
u_R->set(himmel.astro()->getEquToHorTransform());
}
const osg::Matrixf Astronomy::moonOrientation(
const t_aTime &aTime
, const float latitude
, const float longitude) const
{
const t_julianDay t(jd(aTime));
t_longf l, b;
Moon::opticalLibrations(t, l, b);
const osg::Matrixf libLat = osg::Matrixf::rotate(_rad(b), -1, 0, 0);
const osg::Matrixf libLon = osg::Matrixf::rotate(_rad(l), 0, 1, 0);
const float a = _rad(Moon::positionAngleOfAxis(t));
const float p = _rad(Moon::parallacticAngle(aTime, latitude, longitude));
const osg::Matrixf zenith = osg::Matrixf::rotate(p - a, 0, 0, 1);
// finalOrientationWithLibrations
const osg::Matrixf R(libLat * libLon * zenith);
return R;
}
