C++ (Cpp) Angle::accurate_half_sin Examples

Example #1

File: Math.cpp Project: MindMil/XCSoar

/**
 * Calculates the distance and bearing of two locations
 * @param loc1 Location 1
 * @param loc2 Location 2
 * @param Distance Pointer to the distance variable
 * @param Bearing Pointer to the bearing variable
 */
static void
DistanceBearingS(const GeoPoint &loc1, const GeoPoint &loc2,
                 Angle *distance, Angle *bearing)
{
  assert(loc1.IsValid());
  assert(loc2.IsValid());

  const auto sc1 = loc1.latitude.SinCos();
  fixed sin_lat1 = sc1.first, cos_lat1 = sc1.second;
  const auto sc2 = loc2.latitude.SinCos();
  fixed sin_lat2 = sc2.first, cos_lat2 = sc2.second;

  const Angle dlon = loc2.longitude - loc1.longitude;

  if (distance) {
    const fixed s1 = (loc2.latitude - loc1.latitude).accurate_half_sin();
    const fixed s2 = dlon.accurate_half_sin();
    const fixed a = sqr(s1) + SmallMult(cos_lat1, cos_lat2) * sqr(s2);

    Angle distance2 = EarthDistance(a);
    assert(!negative(distance2.Native()));
    *distance = distance2;
  }

  if (bearing) {
    // speedup for fixed since this is one call
    const auto sc = dlon.SinCos();
    const fixed sin_dlon = sc.first, cos_dlon = sc.second;

    const fixed y = SmallMult(sin_dlon, cos_lat2);
    const fixed x = SmallMult(cos_lat1, sin_lat2)
      - SmallMult(sin_lat1, cos_lat2, cos_dlon);

    *bearing = (x == fixed(0) && y == fixed(0))
      ? Angle::Zero()
      : Angle::FromXY(x, y).AsBearing();
  }

#ifdef INSTRUMENT_TASK
  count_distbearing++;
#endif
}

Example #2

File: SimplifiedMath.cpp Project: ThomasXBMC/XCSoar

void
DistanceBearingS(const GeoPoint &loc1, const GeoPoint &loc2,
                 Angle *distance, Angle *bearing)
{
  assert(loc1.IsValid());
  assert(loc2.IsValid());

  const auto sc1 = loc1.latitude.SinCos();
  auto sin_lat1 = sc1.first, cos_lat1 = sc1.second;
  const auto sc2 = loc2.latitude.SinCos();
  auto sin_lat2 = sc2.first, cos_lat2 = sc2.second;

  const Angle dlon = loc2.longitude - loc1.longitude;

  if (distance) {
    const auto s1 = (loc2.latitude - loc1.latitude).accurate_half_sin();
    const auto s2 = dlon.accurate_half_sin();
    const auto a = Square(s1) + cos_lat1 * cos_lat2 * Square(s2);

    Angle distance2 = EarthDistance(a);
    assert(!distance2.IsNegative());
    *distance = distance2;
  }

  if (bearing) {
    // speedup for fixed since this is one call
    const auto sc = dlon.SinCos();
    const auto sin_dlon = sc.first, cos_dlon = sc.second;

    const auto y = sin_dlon * cos_lat2;
    const auto x = cos_lat1 * sin_lat2 - sin_lat1 * cos_lat2 * cos_dlon;

    *bearing = (x == fixed(0) && y == fixed(0))
      ? Angle::Zero()
      : Angle::FromXY(x, y).AsBearing();
  }

#ifdef INSTRUMENT_TASK
  count_distbearing++;
#endif
}

Example #3

File: SimplifiedMath.cpp Project: Advi42/XCSoar

void
DistanceBearingS(const GeoPoint &loc1, const GeoPoint &loc2,
                 Angle *distance, Angle *bearing)
{
  assert(loc1.IsValid());
  assert(loc2.IsValid());

  const auto sc1 = loc1.latitude.SinCos();
  auto sin_lat1 = sc1.first, cos_lat1 = sc1.second;
  const auto sc2 = loc2.latitude.SinCos();
  auto sin_lat2 = sc2.first, cos_lat2 = sc2.second;

  const Angle dlon = loc2.longitude - loc1.longitude;

  if (distance) {
    const auto s1 = (loc2.latitude - loc1.latitude).accurate_half_sin();
    const auto s2 = dlon.accurate_half_sin();
    const auto a = Square(s1) + cos_lat1 * cos_lat2 * Square(s2);

    Angle distance2 = EarthDistance(a);
    assert(!distance2.IsNegative());
    *distance = distance2;
  }

  if (bearing) {
    const auto sc = dlon.SinCos();
    const auto sin_dlon = sc.first, cos_dlon = sc.second;

    const auto y = sin_dlon * cos_lat2;
    const auto x = cos_lat1 * sin_lat2 - sin_lat1 * cos_lat2 * cos_dlon;

    *bearing = (x == 0 && y == 0)
      ? Angle::Zero()
      : Angle::FromXY(x, y).AsBearing();
  }
}