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What do you know, more tidying.

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This commit is contained in:
curt 2000-07-07 21:56:25 +00:00
parent cb29dcc238
commit 5c3b569e97
2 changed files with 87 additions and 101 deletions
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144
simgear/timing/sg_time.cxx
View File

@ -65,7 +65,6 @@
SGTime::SGTime( const string& root )
{
FGPath zone( root );
zone.append( "Timezone" );
zone.append( "zone.tab" );
FG_LOG( FG_EVENT, FG_DEBUG, "Reading timezone info from: " << zone.str() );
@ -108,7 +107,6 @@ void SGTime::init( double lon, double lat, const string& root )
GeoCoord* nearestTz = tzContainer->getNearest(location);
FGPath zone( root );
zone.append( "Timezone" );
zone.append( nearestTz->getDescription() );
// cout << "Using " << zone.str() << " for timezone information" << endl;
@ -129,8 +127,67 @@ void SGTime::init( double lon, double lat, const string& root )
}
// given Julian Date and Longitude (decimal degrees West) compute
// Local Sidereal Time, in decimal hours.
//
// Provided courtesy of ecdowney@noao.edu (Elwood Downey)
static double sidereal_precise( double mjd, double lng )
{
/* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ",
mjd + MJD0, lng); */
// convert to required internal units
lng *= DEG_TO_RAD;
// compute LST and print
double gst = sgTimeCalcGST( mjd );
double lst = gst - RADHR( lng );
lst -= 24.0 * floor( lst / 24.0 );
// printf ("%7.4f\n", lstTmp);
return lst;
}
// return a courser but cheaper estimate of sidereal time
static double sidereal_course( time_t cur_time, struct tm *gmt, double lng )
{
time_t start_gmt, now;
double diff, part, days, hours, lstTmp;
char tbuf[64];
now = cur_time;
start_gmt = sgTimeGetGMT(gmt->tm_year, 2, 21, 12, 0, 0);
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);
FG_LOG( FG_EVENT, FG_DEBUG,
" Time since 3/21/" << gmt->tm_year << " GMT = " << diff );
part = fmod(diff, 1.0);
days = diff - part;
hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0;
lstTmp = (days - lng)/15.0 + hours - 12;
while ( lstTmp < 0.0 ) {
lstTmp += 24.0;
}
FG_LOG( FG_EVENT, FG_DEBUG,
" days = " << days << " hours = " << hours << " lon = "
<< lng << " lst = " << lstTmp );
return lstTmp;
}
// Update the time related variables
void SGTime::update( double lon, double lat, double alt_m, long int warp ) {
void SGTime::update( double lon, double lat, long int warp ) {
double gst_precise, gst_course;
FG_LOG( FG_EVENT, FG_DEBUG, "Updating time" );
@ -171,23 +228,23 @@ void SGTime::update( double lon, double lat, double alt_m, long int warp ) {
// 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_precise = gst = sidereal_precise( mjd, 0.00 );
gst_course = sidereal_course( cur_time, gmt, 0.00 );
gst_diff = gst_precise - gst_course;
lst = sidereal_course(-(lon * RAD_TO_DEG)) + gst_diff;
lst = sidereal_course( cur_time, gmt, -(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;
gst = sidereal_course( cur_time, gmt, 0.00 ) + gst_diff;
lst = sidereal_course( cur_time, gmt, -(lon * RAD_TO_DEG) ) + gst_diff;
}
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))
<< sidereal_precise( mjd, -(lon * RAD_TO_DEG) )
<< ") (diff = " << gst_diff << ")" );
}
@ -200,82 +257,19 @@ void SGTime::updateLocal( double lon, double lat, const string& root )
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())) );
currGMT = sgTimeGetGMT( gmtime(&cur_time) );
aircraftLocalTime = sgTimeGetGMT( (fgLocaltime(&cur_time, zone.c_str())) );
local_offset = aircraftLocalTime - currGMT;
// cout << "Using " << local_offset << " as local time offset Timezone is "
// << zonename << endl;
}
// given Julian Date and Longitude (decimal degrees West) compute
// Local Sidereal Time, in decimal hours.
//
// Provided courtesy of ecdowney@noao.edu (Elwood Downey)
double SGTime::sidereal_precise( double lng )
{
double lstTmp;
/* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ",
mjd + MJD0, lng); */
// convert to required internal units
lng *= DEG_TO_RAD;
// compute LST and print
gst = sgTimeCalcGST( mjd );
lstTmp = gst - RADHR (lng);
lstTmp -= 24.0*floor(lstTmp/24.0);
// printf ("%7.4f\n", lstTmp);
// that's all
return (lstTmp);
}
// return a courser but cheaper estimate of sidereal time
double SGTime::sidereal_course( double lng )
{
time_t start_gmt, now;
double diff, part, days, hours, lstTmp;
char tbuf[64];
now = cur_time;
start_gmt = get_gmt(gmt->tm_year, 2, 21, 12, 0, 0);
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);
FG_LOG( FG_EVENT, FG_DEBUG,
" Time since 3/21/" << gmt->tm_year << " GMT = " << diff );
part = fmod(diff, 1.0);
days = diff - part;
hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0;
lstTmp = (days - lng)/15.0 + hours - 12;
while ( lstTmp < 0.0 ) {
lstTmp += 24.0;
}
FG_LOG( FG_EVENT, FG_DEBUG,
" days = " << days << " hours = " << hours << " lon = "
<< lng << " lst = " << lstTmp );
return(lstTmp);
}
// 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.
@ -397,7 +391,7 @@ double sgTimeCalcGST( double mjd ) {
// If you are having problems with incorrectly positioned astronomical
// bodies, this is a really good place to start looking.
time_t SGTime::get_gmt(int year, int month, int day, int hour, int min, int sec)
time_t sgTimeGetGMT(int year, int month, int day, int hour, int min, int sec)
{
struct tm mt;

44
simgear/timing/sg_time.hxx
View File

@ -90,45 +90,37 @@ public:
void init( double lon, double lat, const string& root );
// Update the time related variables
void update( double lon, double lat, double alt_m, long int warp );
void update( double lon, double lat, long int warp = 0 );
// Given lon/lat, update timezone information and local_offset
void updateLocal( double lon, double lat, const string& root );
// 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_gmt(int year, int month, int day,
int hour, int minute, int second);
time_t get_gmt(struct tm* the_time);
inline time_t get_cur_time() const { return cur_time; };
inline char* get_zonename() const { return zonename; }
inline struct tm* getGmt()const { return gmt; };
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; }
};
// 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)
time_t sgTimeGetGMT(int year, int month, int day,
int hour, int minute, int second);
// this is just a wrapper
inline time_t SGTime::get_gmt(struct tm* the_time) {
inline time_t sgTimeGetGMT(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);
return sgTimeGetGMT(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