Function FSphereLocal

xcharts1.cpp:4174–4192

// horizon meridian, zodiac position and latitude, or Earth coordinates.

flag FSphereLocal(real azi, real alt, CONST CIRC *pcr, int *xp, int *yp)
{
  if (gs.fEcliptic) {
    azi = Mod(azi - rDegQuad); neg(alt);
    CoorXform(&azi, &alt, Lat - rDegQuad);
    azi = Mod(cp0.lonMC - azi + rDegQuad);
    EquToEcl(&azi, &alt);
    azi = rDegMax - Untropical(azi); neg(alt);
  } else {
    if (us.fRefract)
      alt = -SwissRefract(-alt);
  }
  azi = Mod(rDegQuad*3 - (azi + gs.rRot));
  if (gs.rTilt != 0.0)
    CoorXform(&azi, &alt, gs.rTilt);
  *xp = pcr->xc + (int)((real)pcr->xr * RCosD(azi) * RCosD(alt) - rRound);
  *yp = pcr->yc + (int)((real)pcr->yr * RSinD(alt) - rRound);
  return azi >= rDegHalf;
}

flag FSpherePrime(real azi, real alt, CONST CIRC *pcr, int *xp, int *yp)
{