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Rewrote sidereal_course with simpler parameters.

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curt 1998-08-24 20:12:16 +00:00
parent aaa7174002
commit 2b706a6528
1 changed files with 13 additions and 12 deletions
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25
Time/fg_time.cxx
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@ -178,7 +178,7 @@ double cal_mjd (int mn, double dy, int yr) {
}
// given an mjd, return greenwich mean siderial time, gst
// given an mjd, return greenwich mean sidereal time, gst
double utc_gst (double mjd) {
double gst;
@ -322,10 +322,13 @@ time_t get_start_gmt(int year) {
// return a courser but cheaper estimate of sidereal time
double sidereal_course(struct tm *gmt, time_t now, double lng) {
time_t start_gmt;
double sidereal_course(fgTIME *t, double lng) {
struct tm *gmt;
time_t start_gmt, now;
double diff, part, days, hours, lst;
gmt = t->gmt;
now = t->cur_time;
start_gmt = get_start_gmt(gmt->tm_year);
fgPrintf(FG_EVENT, FG_DEBUG,
@ -403,19 +406,14 @@ void fgTimeUpdate(fgFLIGHT *f, fgTIME *t) {
// calculation to get the difference.
fgPrintf( FG_EVENT, FG_INFO, " First time, doing precise gst\n");
t->gst = gst_precise = sidereal_precise(t->mjd, 0.00);
gst_course = sidereal_course(t->gmt, t->cur_time, 0.00);
gst_course = sidereal_course(t, 0.00);
t->gst_diff = gst_precise - gst_course;
t->lst =
sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
+ t->gst_diff;
t->lst = sidereal_course(t, -(FG_Longitude * RAD_TO_DEG)) + t->gst_diff;
} else {
// course + difference should drift off very slowly
t->gst =
sidereal_course(t->gmt, t->cur_time, 0.00) + t->gst_diff;
t->lst =
sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
+ t->gst_diff;
t->gst = sidereal_course(t, 0.00) + t->gst_diff;
t->lst = sidereal_course(t, -(FG_Longitude * RAD_TO_DEG)) + t->gst_diff;
}
fgPrintf( FG_EVENT, FG_DEBUG,
" Current lon=0.00 Sidereal Time = %.3f\n", t->gst);
@ -427,6 +425,9 @@ void fgTimeUpdate(fgFLIGHT *f, fgTIME *t) {
// $Log$
// Revision 1.15 1998/08/24 20:12:16 curt
// Rewrote sidereal_course with simpler parameters.
//
// Revision 1.14 1998/08/05 00:20:07 curt
// Added a local routine to update lighting params every frame when time is
// accelerated.