GridGenerator::GridGenerator(unsigned long seed) : _re(seed)
{
setYawAngle(0., 2 * M_PI);
setPitchAngle(to_radian(-12), to_radian(15));
setRollAngle(0, 1./to_radian(10));
setRadius(25.4, 1.1);
setCenter(0, 3);
}
sf::Vector2f Math::cartesian(float radius, float angle_degrees)
{
angle_degrees += 90.f;
return sf::Vector2f{ std::cos(to_radian(angle_degrees)), std::sin(to_radian(angle_degrees)) } * radius;
}
/*
* Algorithm from http://williams.best.vwh.net/sunrise_sunset_algorithm.htm
* Inspiration from https://gist.github.com/Tafkas/4742250/
* sunrise == true -> sunrise
* sunrise == false -> sunset
* */
struct tm *calculate_sunrise(bool sunrise, int day, int month, int year, double latitude, double longitude, double local_offset)
{
int day_of_year = calculate_day_of_year(day, month, year);
double zenith = 90.83333333333333;
/* convert the longitude to hour value and calculate an approximate time */
double lngHour = longitude / 15;
double t;
if (sunrise) {
t = day_of_year + (( 6 - lngHour) / 24);
} else {
t = day_of_year + ((18 - lngHour) / 24);
}
/* calculate the Sun's mean anomaly */
double M = (0.9856 * t) - 3.289;
/* calculate the Sun's true longitude */
double L = M + (1.916 * sin(to_radian(M))) + (0.020 * sin(to_radian(2 * M))) + 282.634;
L = adjust_to_range(L, 0, 360);
/* calculate the Sun's right ascension */
double RA = to_degree(atan(0.91764 * tan(to_radian(L))));
RA = adjust_to_range(RA, 0, 360);
/* right ascension value needs to be in the same quadrant as L */
double Lquadrant = (floor( L / 90)) * 90;
double RAquadrant = (floor(RA / 90)) * 90;
RA = RA + (Lquadrant - RAquadrant);
/* right ascension value needs to be converted into hours */
RA = RA / 15;
/* calculate the Sun's declination */
double sinDec = 0.39782 * sin(to_radian(L));
double cosDec = cos(asin(sinDec));
/* calculate the Sun's local hour angle */
double cosH = (cos(to_radian(zenith)) - (sinDec * sin(to_radian(latitude)))) / (cosDec * cos(to_radian(latitude)));
/* no sunrise or no sunset */
if ((cosH > 1) && sunrise) {
return NULL;
} else if ((cosH < -1) && !sunrise) {
return NULL;
}
/* finish calculating H and convert into hours */
double H;
if (sunrise) {
H = 360 - to_degree(acos(cosH));
} else {
H = to_degree(acos(cosH));
}
H = H / 15;
/* calculate local mean time of rising/setting */
double T = H + RA - (0.06571 * t) - 6.622;
/* adjust back to UTC */
double UTC = T - lngHour;
UTC = adjust_to_range(UTC, 0, 24);
/* convert UTC value to local time zone of latitude/longitude */
double localT = UTC + local_offset;
/* localT is in this form: 12.34567
* hour: floor(12.34567) = 12
* minutes: floor(0.34567 * 60) = floor(20.7402) = 20
* seconds: floor(0.7402 * 60) = floor(44.412) = 44
*/
struct tm *time = calloc(1, sizeof(struct tm));
time->tm_mday = day;
time->tm_mon = month - 1; /* January is 0 */
time->tm_year = year - 1900; /* Saved as years from 1900 */
time->tm_hour = floor(localT);
localT -= time->tm_hour;
localT *= 60;
time->tm_min = floor(localT);
localT -= time->tm_min;
localT *= 60;
time->tm_sec = floor(localT);
return time;
}
