|
|
|
@ -51,6 +51,22 @@
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* A class to calculate and manage a variety of time parameters.
|
|
|
|
|
* The SGTime class provides many real-world time values. It
|
|
|
|
|
* calculates current time in seconds, GMT time, local time zone,
|
|
|
|
|
* local offset in seconds from GMT, Julian date, and sidereal
|
|
|
|
|
* time. All of these operate with seconds as their granularity so
|
|
|
|
|
* this class is not intended for timing sub-second events. These
|
|
|
|
|
* values are intended as input to things like real world lighting
|
|
|
|
|
* calculations and real astronomical object placement.
|
|
|
|
|
|
|
|
|
|
* To properly use the SGTime class there are a couple of things to be
|
|
|
|
|
* aware of. After creating an instance of the class, you will need to
|
|
|
|
|
* periodically (i.e. before every frame) call the update()
|
|
|
|
|
* method. Optionally, if you care about updating time zone
|
|
|
|
|
* information based on your latitude and longitude, you can call the
|
|
|
|
|
* updateLocal() method periodically as your position changes by
|
|
|
|
|
* significant amounts.
|
|
|
|
|
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
class SGTime {
|
|
|
|
@ -95,14 +111,22 @@ public:
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Create an instance based on a specified position and data file path.
|
|
|
|
|
* This creates an instance of the SGTime object. When calling the
|
|
|
|
|
* constructor you need to provide a root path pointing to your
|
|
|
|
|
* time zone definition tree. Optionally, you can call a form of
|
|
|
|
|
* the constructor that accepts your current longitude and
|
|
|
|
|
* latitude in radians.
|
|
|
|
|
*
|
|
|
|
|
* If you don't know your position when you call the SGTime
|
|
|
|
|
* constructor, you can just use the first form (which assumes 0,
|
|
|
|
|
* 0).
|
|
|
|
|
* @param lon current longitude
|
|
|
|
|
* @param lat current latitude
|
|
|
|
|
* @param root root path point to data file location (timezone, etc.)
|
|
|
|
|
*/
|
|
|
|
|
* @param root root path point to data file location (timezone, etc.) */
|
|
|
|
|
SGTime( double lon, double lat, const string& root );
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Create an instance given a data file path
|
|
|
|
|
* Create an instance given a data file path.
|
|
|
|
|
* @param root root path point to data file location (timezone, etc.)
|
|
|
|
|
*/
|
|
|
|
|
SGTime( const string& root );
|
|
|
|
@ -112,22 +136,48 @@ public:
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* Update the time related variables.
|
|
|
|
|
* The update() method requires you to pass in your position and
|
|
|
|
|
* an optional time offset in seconds. The offset (or warp) allows
|
|
|
|
|
* you to offset "sim" time relative to "real" time. The update()
|
|
|
|
|
* method is designed to be called by the host application before
|
|
|
|
|
* every frame.
|
|
|
|
|
* @param lon current longitude
|
|
|
|
|
* @param lat current latitude
|
|
|
|
|
* @param warp an optional time offset specified in seconds. This
|
|
|
|
|
* allows us to advance or rewind "time" if we choose to.
|
|
|
|
|
*/
|
|
|
|
|
* allows us to advance or rewind "time" if we choose to. */
|
|
|
|
|
void update( double lon, double lat, long int warp = 0 );
|
|
|
|
|
|
|
|
|
|
// Given lon/lat, update timezone information and local_offset
|
|
|
|
|
/**
|
|
|
|
|
* Given lon/lat, update timezone information and local_offset
|
|
|
|
|
* The updateLocal() method is intended to be called less
|
|
|
|
|
* frequently - only when your position is likely to be changed
|
|
|
|
|
* enough that your timezone may have changed as well. In the
|
|
|
|
|
* FlightGear project we call updateLocal() every few minutes from
|
|
|
|
|
* our periodic event manager.
|
|
|
|
|
* @param lon current longitude
|
|
|
|
|
* @param lat current latitude
|
|
|
|
|
* @param root base path containing time zone directory */
|
|
|
|
|
void updateLocal( double lon, double lat, const string& root );
|
|
|
|
|
|
|
|
|
|
/** @return current system/unix time in seconds */
|
|
|
|
|
inline time_t get_cur_time() const { return cur_time; };
|
|
|
|
|
|
|
|
|
|
/** @return time zone name for your current position*/
|
|
|
|
|
inline char* get_zonename() const { return zonename; }
|
|
|
|
|
|
|
|
|
|
/** @return GMT in a "brokent down" tm structure */
|
|
|
|
|
inline struct tm* getGmt()const { return gmt; };
|
|
|
|
|
|
|
|
|
|
/** @return julian date */
|
|
|
|
|
inline double getJD() const { return jd; };
|
|
|
|
|
|
|
|
|
|
/** @return modified julian date */
|
|
|
|
|
inline double getMjd() const { return mjd; };
|
|
|
|
|
|
|
|
|
|
/** @return local side real time */
|
|
|
|
|
inline double getLst() const { return lst; };
|
|
|
|
|
|
|
|
|
|
/** @return grenich side real time (lst when longitude == 0) */
|
|
|
|
|
inline double getGst() const { return gst; };
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
@ -135,11 +185,27 @@ public:
|
|
|
|
|
// Some useful utility functions that don't make sense to be part of
|
|
|
|
|
// the SGTime class
|
|
|
|
|
|
|
|
|
|
// Return unix time in seconds for the given data (relative to GMT)
|
|
|
|
|
/**
|
|
|
|
|
* \relates SGTime
|
|
|
|
|
* Return unix time in seconds for the given data (relative to GMT)
|
|
|
|
|
* @param year current GMT year
|
|
|
|
|
* @param month current GMT month
|
|
|
|
|
* @param day current GMT day
|
|
|
|
|
* @param hour current GMT hour
|
|
|
|
|
* @param minute current minute
|
|
|
|
|
* @param second current second
|
|
|
|
|
* @return unix/system time in seconds
|
|
|
|
|
*/
|
|
|
|
|
time_t sgTimeGetGMT(int year, int month, int day,
|
|
|
|
|
int hour, int minute, int second);
|
|
|
|
|
|
|
|
|
|
// this is just a wrapper
|
|
|
|
|
/**
|
|
|
|
|
* \relates SGTime
|
|
|
|
|
* this is just a wrapper for sgTimeGetGMT that allows an alternate
|
|
|
|
|
* form of input parameters.
|
|
|
|
|
* @param the_time the current GMT time in the tm structure
|
|
|
|
|
* @return unix/system time in seconds
|
|
|
|
|
*/
|
|
|
|
|
inline time_t sgTimeGetGMT(struct tm* the_time) {
|
|
|
|
|
// printf("Using: %24s as input\n", asctime(the_time));
|
|
|
|
|
return sgTimeGetGMT(the_time->tm_year,
|
|
|
|
@ -150,15 +216,32 @@ inline time_t sgTimeGetGMT(struct tm* the_time) {
|
|
|
|
|
the_time->tm_sec);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// given a date in months, mn, days, dy, years, yr, return the
|
|
|
|
|
// modified Julian date (number of days elapsed since 1900 jan 0.5),
|
|
|
|
|
// mjd. Adapted from Xephem.
|
|
|
|
|
/**
|
|
|
|
|
* \relates SGTime
|
|
|
|
|
* Given a date in our form, return the equivalent modified Julian
|
|
|
|
|
* date (number of days elapsed since 1900 jan 0.5), mjd. Adapted
|
|
|
|
|
* from Xephem.
|
|
|
|
|
* @param mn month
|
|
|
|
|
* @param dy day
|
|
|
|
|
* @param yr year
|
|
|
|
|
* @return modified julian date */
|
|
|
|
|
double sgTimeCalcMJD(int mn, double dy, int yr);
|
|
|
|
|
|
|
|
|
|
// given an mjd, calculate greenwich mean sidereal time, gst
|
|
|
|
|
/**
|
|
|
|
|
* \relates SGTime
|
|
|
|
|
* Given an mjd, calculate greenwich mean sidereal time, gst
|
|
|
|
|
* @param mjd modified julian date
|
|
|
|
|
* @return greenwich mean sidereal time (gst)
|
|
|
|
|
*/
|
|
|
|
|
double sgTimeCalcGST( double mjd );
|
|
|
|
|
|
|
|
|
|
// format time
|
|
|
|
|
/**
|
|
|
|
|
* \relates SGTime
|
|
|
|
|
* Format time in a pretty form
|
|
|
|
|
* @param p time specified in a tm struct
|
|
|
|
|
* @param buf buffer space to contain the result
|
|
|
|
|
* @return pointer to character array containt the result
|
|
|
|
|
*/
|
|
|
|
|
char* sgTimeFormatTime( const struct tm* p, char* buf );
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|