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Diffstat (limited to 'src/sunclock.cpp')
| -rw-r--r-- | src/sunclock.cpp | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/src/sunclock.cpp b/src/sunclock.cpp new file mode 100644 index 0000000..29400f1 --- /dev/null +++ b/src/sunclock.cpp @@ -0,0 +1,276 @@ +#include <sunclock.hpp> +#include <cmath> +#include <stdexcept> + +inline double rad(double degrees) { + static const double degToRad = 4.0 * atan(1.0) / 180.0; + return degrees * degToRad; +} + +inline double deg(double radians) { + static const double radToDeg = 180.0 / (4.0 * atan(1.0)); + return radians * radToDeg; +} + +Sunclock::Sunclock(double const &latitude_, double const &longitude_, + double const &tz_offset_) + : latitude(latitude_), longitude(longitude_), tz_offset(tz_offset_) {} + +double Sunclock::irradiance() { return irradiance(time(0)); } + +double Sunclock::irradiance(time_t when) { + when = when + (time_t)(tz_offset * 60 * 60); + struct tm *t = gmtime(&when); + double _time_of_day = time_of_day(when); + double _julian_day = julian_day(t, _time_of_day, tz_offset); + double _julian_century = julian_century(_julian_day); + double _mean_obliq_ecliptic = mean_obliq_ecliptic(_julian_century); + double _mean_long_sun = mean_long_sun(_julian_century); + double _mean_anom_sun = mean_anom_sun(_julian_century); + double _sun_eq_of_centre = sun_eq_of_centre(_mean_anom_sun, _julian_century); + double _sun_true_long = sun_true_long(_mean_long_sun, _sun_eq_of_centre); + double _obliq_corr = obliq_corr(_mean_obliq_ecliptic, _julian_century); + double _sun_app_long = sun_app_long(_sun_true_long, _julian_century); + double _eccent_earth_orbit = eccent_earth_orbit(_julian_century); + double _var_y = var_y(_obliq_corr); + double _eq_of_time = + eq_of_time(_var_y, _mean_long_sun, _eccent_earth_orbit, _mean_anom_sun); + double _declination = declination(_obliq_corr, _sun_app_long); + double _true_solar_time = true_solar_time(_time_of_day, _eq_of_time); + double _hour_angle = hour_angle(_true_solar_time); + double _solar_zenith = solar_zenith(_declination, _hour_angle); + return std::cos(rad(_solar_zenith)); +} + +time_t Sunclock::sunrise() { return sunrise(time(0)); } + +time_t Sunclock::sunrise(time_t date) { + date = date + (time_t)(tz_offset * 60 * 60); + struct tm *t = gmtime(&date); + double _time_of_day = time_of_day(date); + double _julian_day = julian_day(t, _time_of_day, tz_offset); + double _julian_century = julian_century(_julian_day); + double _mean_obliq_ecliptic = mean_obliq_ecliptic(_julian_century); + double _mean_long_sun = mean_long_sun(_julian_century); + double _mean_anom_sun = mean_anom_sun(_julian_century); + double _sun_eq_of_centre = sun_eq_of_centre(_mean_anom_sun, _julian_century); + double _sun_true_long = sun_true_long(_mean_long_sun, _sun_eq_of_centre); + double _obliq_corr = obliq_corr(_mean_obliq_ecliptic, _julian_century); + double _sun_app_long = sun_app_long(_sun_true_long, _julian_century); + double _eccent_earth_orbit = eccent_earth_orbit(_julian_century); + double _var_y = var_y(_obliq_corr); + double _eq_of_time = + eq_of_time(_var_y, _mean_long_sun, _eccent_earth_orbit, _mean_anom_sun); + double _declination = declination(_obliq_corr, _sun_app_long); + double _hour_angle_sunrise = hour_angle_sunrise(_declination); + + double noon_decimal_day = + (720 - 4 * longitude - _eq_of_time + tz_offset * 60) / 1440; + double decimal_day = noon_decimal_day - _hour_angle_sunrise * 4 / 1440; + return time_from_decimal_day(date, decimal_day) - + (time_t)(tz_offset * 60 * 60); +} + +time_t Sunclock::solar_noon() { return solar_noon(time(0)); } + +time_t Sunclock::solar_noon(time_t date) { + date = date + (time_t)(tz_offset * 60 * 60); + struct tm *t = gmtime(&date); + double _time_of_day = time_of_day(date); + double _julian_day = julian_day(t, _time_of_day, tz_offset); + double _julian_century = julian_century(_julian_day); + double _mean_obliq_ecliptic = mean_obliq_ecliptic(_julian_century); + double _mean_long_sun = mean_long_sun(_julian_century); + double _mean_anom_sun = mean_anom_sun(_julian_century); + double _obliq_corr = obliq_corr(_mean_obliq_ecliptic, _julian_century); + double _eccent_earth_orbit = eccent_earth_orbit(_julian_century); + double _var_y = var_y(_obliq_corr); + double _eq_of_time = + eq_of_time(_var_y, _mean_long_sun, _eccent_earth_orbit, _mean_anom_sun); + + double decimal_day = + (720 - 4 * longitude - _eq_of_time + tz_offset * 60) / 1440; + return time_from_decimal_day(date, decimal_day) - + (time_t)(tz_offset * 60 * 60); +} + +time_t Sunclock::sunset() { return sunset(time(0)); } + +time_t Sunclock::sunset(time_t date) { + date = date + (time_t)(tz_offset * 60 * 60); + struct tm *t = gmtime(&date); + double _time_of_day = time_of_day(date); + double _julian_day = julian_day(t, _time_of_day, tz_offset); + double _julian_century = julian_century(_julian_day); + double _mean_obliq_ecliptic = mean_obliq_ecliptic(_julian_century); + double _mean_long_sun = mean_long_sun(_julian_century); + double _mean_anom_sun = mean_anom_sun(_julian_century); + double _sun_eq_of_centre = sun_eq_of_centre(_mean_anom_sun, _julian_century); + double _sun_true_long = sun_true_long(_mean_long_sun, _sun_eq_of_centre); + double _obliq_corr = obliq_corr(_mean_obliq_ecliptic, _julian_century); + double _sun_app_long = sun_app_long(_sun_true_long, _julian_century); + double _eccent_earth_orbit = eccent_earth_orbit(_julian_century); + double _var_y = var_y(_obliq_corr); + double _eq_of_time = + eq_of_time(_var_y, _mean_long_sun, _eccent_earth_orbit, _mean_anom_sun); + double _declination = declination(_obliq_corr, _sun_app_long); + double _hour_angle_sunrise = hour_angle_sunrise(_declination); + + double noon_decimal_day = + (720 - 4 * longitude - _eq_of_time + tz_offset * 60) / 1440; + double decimal_day = noon_decimal_day + _hour_angle_sunrise * 4 / 1440; + return time_from_decimal_day(date, decimal_day) - + (time_t)(tz_offset * 60 * 60); +} + +double Sunclock::time_of_day(time_t date) { + struct tm *t = gmtime(&date); + return (t->tm_hour + t->tm_min / 60.0 + t->tm_sec / 3600.0) / 24.0; +} + +time_t Sunclock::time_from_decimal_day(time_t date, double decimal_day) { + struct std::tm epoch; + epoch.tm_isdst = 0; + epoch.tm_sec = epoch.tm_min = epoch.tm_hour = epoch.tm_mon = 0; + epoch.tm_mday = 1; + epoch.tm_year = 70; + time_t local_tz_offset = mktime(&epoch); + + struct tm *dt = gmtime(&date); + struct tm t = {}; + t.tm_year = dt->tm_year; + t.tm_mon = dt->tm_mon; + t.tm_mday = dt->tm_mday; + double hours = 24.0 * decimal_day; + t.tm_hour = int(hours); + double minutes = (hours - t.tm_hour) * 60; + t.tm_min = int(minutes); + double seconds = (minutes - t.tm_sec) * 60; + t.tm_sec = int(seconds) % 60; + return mktime(&t) - local_tz_offset; +} + +int Sunclock::days_since_1900(struct tm *t) { + int year = t->tm_year; + if (year < 0 || year > 199) { + throw std::invalid_argument( + "days_since_1900 - Date must be between 1900 and 2099"); + } + int month = t->tm_mon + 1; + int days = t->tm_mday; + + if (month < 3) { + month += 12; + year--; + } + int yearDays = (int)(year * 365.25); + int monthDays = (int)((month + 1) * 30.61); + + return (yearDays + monthDays + days - 63); +} + +double Sunclock::julian_day(struct tm *t, double const &time_of_day, + double const &tz_offset) { + return days_since_1900(t) + 2415018.5 + time_of_day - tz_offset / 24; +} + +double Sunclock::julian_century(double _julian_day) { + return (_julian_day - 2451545.0) / 36525.0; +} + +double Sunclock::mean_long_sun(double _julian_century) { + return ( + 280.46646 + + fmod(_julian_century * (36000.76983 + _julian_century * 0.0003032), 360)); +} + +double Sunclock::mean_anom_sun(double _julian_century) { + return 357.52911 + + _julian_century * (35999.05029 - 0.0001537 * _julian_century); +} + +double Sunclock::sun_eq_of_centre(double _mean_anom_sun, + double _julian_century) { + return sin(rad(_mean_anom_sun)) * + (1.914602 - + _julian_century * (0.004817 + 0.000014 * _julian_century)) + + sin(rad(2 * _mean_anom_sun)) * + (0.019993 - 0.000101 * _julian_century) + + sin(rad(3 * _mean_anom_sun)) * 0.000289; +} + +double Sunclock::sun_true_long(double _mean_long_sun, + double _sun_eq_of_centre) { + return _mean_long_sun + _sun_eq_of_centre; +} + +double Sunclock::eccent_earth_orbit(double _julian_century) { + return 0.016708634 - + _julian_century * (0.000042037 + 0.0001537 * _julian_century); +} + +double Sunclock::var_y(double _obliq_corr) { + return tan(rad(_obliq_corr / 2)) * tan(rad(_obliq_corr / 2)); +} + +double Sunclock::mean_obliq_ecliptic(double _julian_century) { + return (23 + (26 + ((21.448 - _julian_century * + (46.815 + _julian_century * + (0.00059 - _julian_century * + 0.001813)))) / + 60) / + 60); +} + +double Sunclock::obliq_corr(double _mean_obliq_ecliptic, + double _julian_century) { + return _mean_obliq_ecliptic + + 0.00256 * cos(deg(125.04 - 1934.136 * _julian_century)); +} + +double Sunclock::sun_app_long(double _sun_true_long, double _julian_century) { + return (_sun_true_long - 0.00569 - + 0.00478 * sin(deg(125.04 - 1934.136 * _julian_century))); +} + +double Sunclock::declination(double _obliq_corr, double _sun_app_long) { + return deg(asin(sin(rad(_obliq_corr)) * sin(rad(_sun_app_long)))); +} + +double Sunclock::eq_of_time(double _var_y, double _mean_long_sun, + double _eccent_earth_orbit, double _mean_anom_sun) { + return 4 * deg(_var_y * sin(2 * rad(_mean_long_sun)) - + 2 * _eccent_earth_orbit * sin(rad(_mean_anom_sun)) + + 4 * _eccent_earth_orbit * _var_y * sin(rad(_mean_anom_sun)) * + cos(2 * rad(_mean_long_sun)) - + 0.5 * _var_y * _var_y * sin(4 * rad(_mean_long_sun)) - + 1.25 * _eccent_earth_orbit * _eccent_earth_orbit * + sin(2 * rad(_mean_anom_sun))); +} + +double Sunclock::true_solar_time(double _time_of_day, double _eq_of_time) { + return fmod( + (_time_of_day * 1440 + _eq_of_time + 4 * longitude - 60 * tz_offset), + 1440); +} + +double Sunclock::hour_angle(double _true_solar_time) { + return (_true_solar_time / 4 < 0 ? _true_solar_time / 4 + 180 + : _true_solar_time / 4 - 180); +} + +double Sunclock::hour_angle_sunrise(double _declination) { + return deg( + acos(cos(rad(90.833)) / (cos(rad(latitude)) * cos(rad(_declination))) - + tan(rad(latitude)) * tan(rad(_declination)))); +} + +double Sunclock::solar_zenith(double _declination, double _hour_angle) { + return deg(acos(sin(rad(latitude)) * sin(rad(_declination)) + + cos(rad(latitude)) * cos(rad(_declination)) * + cos(rad(_hour_angle)))); +} + +double Sunclock::solar_elevation(double _solar_zenith) { + return 90 - _solar_zenith; +} |