SGTime::SGTime( const string& root )
{
- /* if (cur_time_params) {
- FG_LOG( FG_GENERAL, FG_ALERT,
- "Error: only one instance of SGTime allowed" );
- exit(-1);
- } */
-
- // cur_time_params = this;
-
FGPath zone( root );
zone.append( "Timezone" );
zone.append( "zone.tab" );
}
}
-void SGTime::updateLocal( double lon, double lat, const string& root )
-{
- time_t currGMT;
- time_t aircraftLocalTime;
- GeoCoord location( RAD_TO_DEG * lat, RAD_TO_DEG * lon );
- GeoCoord* nearestTz = tzContainer->getNearest(location);
- FGPath zone( root );
- zone.append ("Timezone" );
- zone.append ( nearestTz->getDescription() );
- if ( zonename ) {
- delete zonename;
- }
- zonename = strdup( zone.c_str() );
- currGMT = get_gmt( gmtime(&cur_time) );
- aircraftLocalTime = get_gmt( (fgLocaltime(&cur_time, zone.c_str())) );
- local_offset = aircraftLocalTime - currGMT;
- // cout << "Using " << local_offset << " as local time offset Timezone is "
- // << zonename << endl;
-}
-// Initialize the time dependent variables (maybe I'll put this in the
-// constructor later)
+// Initialize the time related variables
void SGTime::init( double lon, double lat, const string& root )
-// time_t timeOffset, sgTimingOffsetType offsetType )
{
FG_LOG( FG_EVENT, FG_INFO, "Initializing Time" );
gst_diff = -9999.0;
}
-// 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.
+// Update the time related variables
+void SGTime::update( double lon, double lat, double alt_m, long int warp ) {
+ double gst_precise, gst_course;
-void SGTime::cal_mjd (int mn, double dy, int yr)
-{
- //static double last_mjd, last_dy;
- //double mjd;
- //static int last_mn, last_yr;
- int b, d, m, y;
- long c;
-
- if (mn == last_mn && yr == last_yr && dy == last_dy) {
- mjd = last_mjd;
- }
-
- m = mn;
- y = (yr < 0) ? yr + 1 : yr;
- if (mn < 3) {
- m += 12;
- y -= 1;
- }
-
- if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) {
- b = 0;
- } else {
- int a;
- a = y/100;
- b = 2 - a + a/4;
- }
-
- if (y < 0) {
- c = (long)((365.25*y) - 0.75) - 694025L;
+ FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" );
+
+ // get current Unix calendar time (in seconds)
+ // warp += warp_delta;
+ cur_time = time(NULL) + warp;
+ FG_LOG( FG_EVENT, FG_DEBUG,
+ " Current Unix calendar time = " << cur_time
+ << " warp = " << warp );
+
+ // get GMT break down for current time
+ gmt = gmtime(&cur_time);
+ FG_LOG( FG_EVENT, FG_DEBUG,
+ " Current GMT = " << gmt->tm_mon+1 << "/"
+ << gmt->tm_mday << "/" << gmt->tm_year << " "
+ << gmt->tm_hour << ":" << gmt->tm_min << ":"
+ << gmt->tm_sec );
+
+ // calculate modified Julian date
+ // t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday,
+ // (int)(t->gmt->tm_year + 1900));
+ mjd = sgTimeCalcMJD( (int)(gmt->tm_mon+1), (double)gmt->tm_mday,
+ (int)(gmt->tm_year + 1900) );
+
+ // add in partial day
+ mjd += (gmt->tm_hour / 24.0) + (gmt->tm_min / (24.0 * 60.0)) +
+ (gmt->tm_sec / (24.0 * 60.0 * 60.0));
+
+ // convert "back" to Julian date + partial day (as a fraction of one)
+ jd = mjd + MJD0;
+ FG_LOG( FG_EVENT, FG_DEBUG, " Current Julian Date = " << jd );
+
+ // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG);
+
+ // Calculate local side real time
+ if ( gst_diff < -100.0 ) {
+ // first time through do the expensive calculation & cheap
+ // calculation to get the difference.
+ FG_LOG( FG_EVENT, FG_INFO, " First time, doing precise gst" );
+ gst_precise = gst = sidereal_precise(0.00);
+ gst_course = sidereal_course(0.00);
+
+ gst_diff = gst_precise - gst_course;
+
+ lst = sidereal_course(-(lon * RAD_TO_DEG)) + gst_diff;
} else {
- c = (long)(365.25*y) - 694025L;
+ // course + difference should drift off very slowly
+ gst = sidereal_course( 0.00 ) + gst_diff;
+ lst = sidereal_course( -(lon * RAD_TO_DEG)) + gst_diff;
}
-
- d = (int)(30.6001*(m+1));
-
- mjd = b + c + d + dy - 0.5;
-
- last_mn = mn;
- last_dy = dy;
- last_yr = yr;
- last_mjd = mjd;
+
+ FG_LOG( FG_EVENT, FG_DEBUG,
+ " Current lon=0.00 Sidereal Time = " << gst );
+ FG_LOG( FG_EVENT, FG_DEBUG,
+ " Current LOCAL Sidereal Time = " << lst << " ("
+ << sidereal_precise(-(lon * RAD_TO_DEG))
+ << ") (diff = " << gst_diff << ")" );
}
-// given an mjd, calculate greenwich mean sidereal time, gst
-void SGTime::utc_gst ()
+// Given lon/lat, update timezone information and local_offset
+void SGTime::updateLocal( double lon, double lat, const string& root )
{
- double day = floor(mjd-0.5)+0.5;
- double hr = (mjd-day)*24.0;
- double T, x;
-
- T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0;
- x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T;
- x /= 3600.0;
- gst = (1.0/SIDRATE)*hr + x;
-
- FG_LOG( FG_EVENT, FG_DEBUG, " gst => " << gst );
+ time_t currGMT;
+ time_t aircraftLocalTime;
+ GeoCoord location( RAD_TO_DEG * lat, RAD_TO_DEG * lon );
+ GeoCoord* nearestTz = tzContainer->getNearest(location);
+ FGPath zone( root );
+ zone.append ("Timezone" );
+ zone.append ( nearestTz->getDescription() );
+ if ( zonename ) {
+ delete zonename;
+ }
+ zonename = strdup( zone.c_str() );
+ currGMT = get_gmt( gmtime(&cur_time) );
+ aircraftLocalTime = get_gmt( (fgLocaltime(&cur_time, zone.c_str())) );
+ local_offset = aircraftLocalTime - currGMT;
+ // cout << "Using " << local_offset << " as local time offset Timezone is "
+ // << zonename << endl;
}
// Local Sidereal Time, in decimal hours.
//
// Provided courtesy of ecdowney@noao.edu (Elwood Downey)
-
-double SGTime::sidereal_precise (double lng)
+double SGTime::sidereal_precise( double lng )
{
double lstTmp;
lng *= DEG_TO_RAD;
// compute LST and print
- utc_gst();
+ gst = sgTimeCalcGST( mjd );
lstTmp = gst - RADHR (lng);
lstTmp -= 24.0*floor(lstTmp/24.0);
// printf ("%7.4f\n", lstTmp);
// return a courser but cheaper estimate of sidereal time
-double SGTime::sidereal_course(double lng)
+double SGTime::sidereal_course( double lng )
{
- //struct tm *gmt;
- //double lstTmp;
time_t start_gmt, now;
double diff, part, days, hours, lstTmp;
char tbuf[64];
- //gmt = t->gmt;
- //now = t->cur_time;
now = cur_time;
start_gmt = get_gmt(gmt->tm_year, 2, 21, 12, 0, 0);
- FG_LOG( FG_EVENT, FG_DEBUG, " COURSE: GMT = " << format_time(gmt, tbuf) );
+ FG_LOG( FG_EVENT, FG_DEBUG, " COURSE: GMT = "
+ << sgTimeFormatTime(gmt, tbuf) );
FG_LOG( FG_EVENT, FG_DEBUG, " March 21 noon (GMT) = " << start_gmt );
diff = (now - start_gmt) / (3600.0 * 24.0);
}
-// Update time variables such as gmt, julian date, and sidereal time
-void SGTime::update( double lon, double lat, double alt_m, long int warp ) {
- double gst_precise, gst_course;
-
- FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" );
+// 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.
+double sgTimeCalcMJD(int mn, double dy, int yr) {
+ double mjd;
- // get current Unix calendar time (in seconds)
- // warp += warp_delta;
- cur_time = time(NULL) + warp;
- FG_LOG( FG_EVENT, FG_DEBUG,
- " Current Unix calendar time = " << cur_time
- << " warp = " << warp );
+ // internal book keeping data
+ static double last_mjd, last_dy;
+ static int last_mn, last_yr;
- // get GMT break down for current time
- gmt = gmtime(&cur_time);
- FG_LOG( FG_EVENT, FG_DEBUG,
- " Current GMT = " << gmt->tm_mon+1 << "/"
- << gmt->tm_mday << "/" << gmt->tm_year << " "
- << gmt->tm_hour << ":" << gmt->tm_min << ":"
- << gmt->tm_sec );
+ int b, d, m, y;
+ long c;
+
+ if (mn == last_mn && yr == last_yr && dy == last_dy) {
+ mjd = last_mjd;
+ }
+
+ m = mn;
+ y = (yr < 0) ? yr + 1 : yr;
+ if (mn < 3) {
+ m += 12;
+ y -= 1;
+ }
+
+ if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) {
+ b = 0;
+ } else {
+ int a;
+ a = y/100;
+ b = 2 - a + a/4;
+ }
+
+ if (y < 0) {
+ c = (long)((365.25*y) - 0.75) - 694025L;
+ } else {
+ c = (long)(365.25*y) - 694025L;
+ }
+
+ d = (int)(30.6001*(m+1));
+
+ mjd = b + c + d + dy - 0.5;
+
+ last_mn = mn;
+ last_dy = dy;
+ last_yr = yr;
+ last_mjd = mjd;
- // calculate modified Julian date
- // t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday,
- // (int)(t->gmt->tm_year + 1900));
- cal_mjd ((int)(gmt->tm_mon+1), (double)gmt->tm_mday,
- (int)(gmt->tm_year + 1900));
+ return mjd;
+}
- // add in partial day
- mjd += (gmt->tm_hour / 24.0) + (gmt->tm_min / (24.0 * 60.0)) +
- (gmt->tm_sec / (24.0 * 60.0 * 60.0));
- // convert "back" to Julian date + partial day (as a fraction of one)
- jd = mjd + MJD0;
- FG_LOG( FG_EVENT, FG_DEBUG, " Current Julian Date = " << jd );
+// given an mjd, calculate greenwich mean sidereal time, gst
+double sgTimeCalcGST( double mjd ) {
+ double gst;
- // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG);
+ double day = floor(mjd-0.5)+0.5;
+ double hr = (mjd-day)*24.0;
+ double T, x;
- // Calculate local side real time
- if ( gst_diff < -100.0 ) {
- // first time through do the expensive calculation & cheap
- // calculation to get the difference.
- FG_LOG( FG_EVENT, FG_INFO, " First time, doing precise gst" );
- gst_precise = gst = sidereal_precise(0.00);
- gst_course = sidereal_course(0.00);
-
- gst_diff = gst_precise - gst_course;
+ T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0;
+ x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T;
+ x /= 3600.0;
+ gst = (1.0/SIDRATE)*hr + x;
- lst = sidereal_course(-(lon * RAD_TO_DEG)) + gst_diff;
- } else {
- // course + difference should drift off very slowly
- gst = sidereal_course( 0.00 ) + gst_diff;
- lst = sidereal_course( -(lon * RAD_TO_DEG)) + gst_diff;
- }
+ FG_LOG( FG_EVENT, FG_DEBUG, " gst => " << gst );
- FG_LOG( FG_EVENT, FG_DEBUG,
- " Current lon=0.00 Sidereal Time = " << gst );
- FG_LOG( FG_EVENT, FG_DEBUG,
- " Current LOCAL Sidereal Time = " << lst << " ("
- << sidereal_precise(-(lon * RAD_TO_DEG))
- << ") (diff = " << gst_diff << ")" );
+ return gst;
}
+#if defined( HAVE_TIMEGM )
+ // ignore this function
+#elif defined( MK_TIME_IS_GMT )
+ // ignore this function
+#else // ! defined ( MK_TIME_IS_GMT )
+
+ // Fix up timezone if using ftime()
+ static long int fix_up_timezone( long int timezone_orig ) {
+# if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME )
+ // ftime() needs a little extra help finding the current timezone
+ struct timeb current;
+ ftime(¤t);
+ return( current.timezone * 60 );
+# else
+ return( timezone_orig );
+# endif
+ }
+#endif
+
+
/******************************************************************
* The following are some functions that were included as SGTime
* members, although they currently don't make use of any of the
#endif // ! defined ( MK_TIME_IS_GMT )
}
-// Fix up timezone if using ftime()
-long int SGTime::fix_up_timezone( long int timezone_orig )
-{
-#if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME )
- // ftime() needs a little extra help finding the current timezone
- struct timeb current;
- ftime(¤t);
- return( current.timezone * 60 );
-#else
- return( timezone_orig );
-#endif
-}
-
-char* SGTime::format_time( const struct tm* p, char* buf )
+// format time
+char* sgTimeFormatTime( const struct tm* p, char* buf )
{
sprintf( buf, "%d/%d/%2d %d:%02d:%02d",
p->tm_mon, p->tm_mday, p->tm_year,
p->tm_hour, p->tm_min, p->tm_sec);
return buf;
}
-
-
-// SGTime* SGTime::cur_time_params = 0;
# include <config.h>
#endif
-#ifdef HAVE_WINDOWS_H
-# include <windows.h>
-#endif
-
-#include <GL/glut.h>
-
#include <simgear/compiler.h>
#ifdef FG_HAVE_STD_INCLUDES
# include <time.h>
#endif
-// #include <FDM/flight.hxx>
-
#include "timezone.h"
-// #include "lowleveltime.h"
-
-
-enum sgTimingOffsetType {
- SG_TIME_SYS_OFFSET = 0,
- SG_TIME_GMT_OFFSET = 1,
- SG_TIME_LAT_OFFSET = 2,
- SG_TIME_SYS_ABSOLUTE = 3,
- SG_TIME_GMT_ABSOLUTE = 4,
- SG_TIME_LAT_ABSOLUTE = 5
-};
// Define a structure containing time parameters
// local sidereal time
double lst;
- // the difference between the precise sidereal time algorithm
- // result and the course result. course_gst + diff has good
- // accuracy for the short term
+ // the difference between the precise / expensive sidereal time
+ // algorithm result and the quick course result. course_gst +
+ // gst_diff has pretty good accuracy over the span of a couple hours
double gst_diff;
- // internal book keeping data
- double last_mjd, last_dy;
- int last_mn, last_yr;
-
public:
SGTime( const string& root );
~SGTime();
- inline double getJD() const { return jd; };
- inline double getMjd() const { return mjd; };
- inline double getLst() const { return lst; };
- inline double getGst() const { return gst; };
- inline time_t get_cur_time() const { return cur_time; };
- inline struct tm* getGmt()const { return gmt; };
-
- // void adjust_warp(int val) { warp += val; };
- // void adjust_warp_delta(int val) { warp_delta += val; };
-
- // Initialize the time dependent variables
+ // Initialize the time related variables
void init( double lon, double lat, const string& root );
- // time_t timeOffset, sgTimingOffsetType offsetType );
- // Update the time dependent variables
+ // Update the time related variables
void update( double lon, double lat, double alt_m, long int warp );
+
+ // Given lon/lat, update timezone information and local_offset
void updateLocal( double lon, double lat, const string& root );
- void cal_mjd (int mn, double dy, int yr);
- void utc_gst();
- double sidereal_precise (double lng);
- double sidereal_course(double lng);
- // static SGTime *cur_time_params;
+ // given Julian Date and Longitude (decimal degrees West) compute
+ // Local Sidereal Time, in decimal hours.
+ //
+ // Provided courtesy of ecdowney@noao.edu (Elwood Downey)
+ double sidereal_precise( double lng );
+
+ // return a courser but cheaper estimate of sidereal time
+ double sidereal_course( double lng );
// Some other stuff which were changed to SGTime members on
// questionable grounds -:)
- // time_t get_start_gmt(int year);
time_t get_gmt(int year, int month, int day,
int hour, int minute, int second);
time_t get_gmt(struct tm* the_time);
+ inline double getJD() const { return jd; };
+ inline double getMjd() const { return mjd; };
+ inline double getLst() const { return lst; };
+ inline double getGst() const { return gst; };
+ inline time_t get_cur_time() const { return cur_time; };
+ inline struct tm* getGmt()const { return gmt; };
inline char* get_zonename() const { return zonename; }
-
- char* format_time( const struct tm* p, char* buf );
- long int fix_up_timezone( long int timezone_orig );
-
- // inline int get_warp_delta() const { return warp_delta; }
};
-inline time_t SGTime::get_gmt(struct tm* the_time) // this is just a wrapper
-{
- //printf("Using: %24s as input\n", asctime(the_time));
- return get_gmt(the_time->tm_year,
- the_time->tm_mon,
- the_time->tm_mday,
- the_time->tm_hour,
- the_time->tm_min,
- the_time->tm_sec);
+// this is just a wrapper
+inline time_t SGTime::get_gmt(struct tm* the_time) {
+ // printf("Using: %24s as input\n", asctime(the_time));
+ return get_gmt(the_time->tm_year,
+ the_time->tm_mon,
+ the_time->tm_mday,
+ the_time->tm_hour,
+ the_time->tm_min,
+ 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.
+double sgTimeCalcMJD(int mn, double dy, int yr);
+
+// given an mjd, calculate greenwich mean sidereal time, gst
+double sgTimeCalcGST( double mjd );
+
+// format time
+char* sgTimeFormatTime( const struct tm* p, char* buf );
+
#endif // _SG_TIME_HXX
projects / simgear.git / commitdiff