inline std::pair<double, FloatCoordinate> projectPointOnSegment(const FloatCoordinate &source,
const FloatCoordinate &target,
const FloatCoordinate &coordinate)
{
const FloatCoordinate slope_vector{target.lon - source.lon, target.lat - source.lat};
const FloatCoordinate rel_coordinate{coordinate.lon - source.lon, coordinate.lat - source.lat};
// dot product of two un-normed vectors
const auto unnormed_ratio = static_cast<double>(slope_vector.lon * rel_coordinate.lon) +
static_cast<double>(slope_vector.lat * rel_coordinate.lat);
// squared length of the slope vector
const auto squared_length = static_cast<double>(slope_vector.lon * slope_vector.lon) +
static_cast<double>(slope_vector.lat * slope_vector.lat);
if (squared_length < std::numeric_limits<double>::epsilon())
{
return {0, source};
}
const double normed_ratio = unnormed_ratio / squared_length;
double clamped_ratio = normed_ratio;
if (clamped_ratio > 1.)
{
clamped_ratio = 1.;
}
else if (clamped_ratio < 0.)
{
clamped_ratio = 0.;
}
return {clamped_ratio,
{
FloatLongitude(1.0 - clamped_ratio) * source.lon +
target.lon * FloatLongitude(clamped_ratio),
FloatLatitude(1.0 - clamped_ratio) * source.lat +
target.lat * FloatLatitude(clamped_ratio),
}};
}
bool FloatCoordinate::IsValid() const
{
return !(lat > FloatLatitude(90) || lat < FloatLatitude(-90) || lon > FloatLongitude(180) ||
lon < FloatLongitude(-180));
}
inline FloatLongitude clamp(const FloatLongitude lon)
{
return std::max(std::min(lon, FloatLongitude(detail::MAX_LONGITUDE)),
FloatLongitude(-detail::MAX_LONGITUDE));
}