fly/flightgear
1
0
Fork 0
Code Activity

Mostly working on stars and generating sidereal time for accurate star

Browse source 
placement.
This commit is contained in:
curt 1997-09-13 01:59:45 +00:00
parent 5d76cf2eaa
commit 45d02e3e68
8 changed files with 217 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
Aircraft/aircraft.c
View file

@ -31,12 +31,12 @@
/* Display various parameters to stdout */
void aircraft_debug(int type) {
void fgAircraftOutputCurrent(struct AIRCRAFT *a) {
struct FLIGHT *f;
struct CONTROLS *c;
f = &current_aircraft.flight;
c = &current_aircraft.controls;
f = &a->flight;
c = &a->controls;
printf("Pos = (%.2f,%.2f,%.2f) (Phi,Theta,Psi)=(%.2f,%.2f,%.2f)\n",
FG_Longitude * 3600.0 * RAD_TO_DEG,
@ -48,9 +48,13 @@ void aircraft_debug(int type) {
/* $Log$
/* Revision 1.10 1997/08/27 03:29:56 curt
/* Changed naming scheme of basic shared structures.
/* Revision 1.11 1997/09/13 02:00:05 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.10 1997/08/27 03:29:56 curt
* Changed naming scheme of basic shared structures.
*
* Revision 1.9 1997/07/19 22:39:08 curt
* Moved PI to ../constants.h
*

10
Aircraft/aircraft.h
View file

@ -44,16 +44,20 @@ extern struct AIRCRAFT current_aircraft;
/* Display various parameters to stdout */
void aircraft_debug(int type);
void fgAircraftOutputCurrent(struct AIRCRAFT *a);
#endif /* AIRCRAFT_H */
/* $Log$
/* Revision 1.5 1997/08/27 03:29:58 curt
/* Changed naming scheme of basic shared structures.
/* Revision 1.6 1997/09/13 02:00:06 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.5 1997/08/27 03:29:58 curt
* Changed naming scheme of basic shared structures.
*
* Revision 1.4 1997/07/23 21:52:17 curt
* Put comments around the text after an #endif for increased portability.
*

19
Main/GLUTmain.c
View file

@ -396,9 +396,16 @@ static void fgMainLoop( void ) {
double cur_elev;
double joy_x, joy_y;
int joy_b1, joy_b2;
struct AIRCRAFT *a;
struct FLIGHT *f;
struct fgTIME *t;
f = &current_aircraft.flight;
a = &current_aircraft;
f = &a->flight;
t = &cur_time_params;
/* update "time" */
fgTimeUpdate(f, t);
/* Read joystick */
/* fgJoystickRead( &joy_x, &joy_y, &joy_b1, &joy_b2 );
@ -447,7 +454,7 @@ static void fgMainLoop( void ) {
FG_Altitude * FEET_TO_METER);
}
aircraft_debug(1);
fgAircraftOutputCurrent(a);
/* redraw display */
fgUpdateVisuals();
@ -555,9 +562,13 @@ int main( int argc, char *argv[] ) {
/* $Log$
/* Revision 1.15 1997/09/05 14:17:27 curt
/* More tweaking with stars.
/* Revision 1.16 1997/09/13 02:00:06 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.15 1997/09/05 14:17:27 curt
* More tweaking with stars.
*
* Revision 1.14 1997/09/05 01:35:53 curt
* Working on getting stars right.
*

15
Simulator/constants.h
View file

@ -80,6 +80,13 @@
#define INVG 0.031080997
/* Time Related Parameters */
#define MJD0 2415020.0
#define J2000 (2451545.0 - MJD0)
#define SIDRATE .9972695677
/* Conversions */
/* Degrees to Radians */
@ -115,9 +122,13 @@
/* $Log$
/* Revision 1.9 1997/08/22 21:34:32 curt
/* Doing a bit of reorganizing and house cleaning.
/* Revision 1.10 1997/09/13 01:59:45 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.9 1997/08/22 21:34:32 curt
* Doing a bit of reorganizing and house cleaning.
*
* Revision 1.8 1997/07/31 22:52:22 curt
* Working on redoing internal coordinate systems & scenery transformations.
*

2
Time/depend
View file

@ -1,5 +1,6 @@
fg_time.o: fg_time.c fg_time.h ../types.h
fg_timer.o: fg_timer.c fg_timer.h
sidereal.o: sidereal.c
sunpos.o: sunpos.c sunpos.h ../types.h fg_time.h ../constants.h \
../GLUT/views.h ../GLUT/../types.h ../GLUT/../Flight/flight.h \
../GLUT/../Flight/Slew/slew.h \
@ -7,3 +8,4 @@ sunpos.o: sunpos.c sunpos.h ../types.h fg_time.h ../constants.h \
../GLUT/../Flight/LaRCsim/../flight.h ../GLUT/../Math/mat3.h \
../Math/fg_geodesy.h ../Math/mat3.h ../Math/polar.h \
../Math/../types.h
ttest.o: ttest.c

144
Time/fg_time.c
View file

@ -24,16 +24,156 @@
**************************************************************************/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "fg_time.h"
#include "../constants.h"
#include "../Flight/flight.h"
#define DEGHR(x) ((x)/15.)
#define RADHR(x) DEGHR(x*RAD_TO_DEG)
struct fgTIME cur_time_params;
/* 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 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;
return(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 = 30.6001*(m+1);
mjd = b + c + d + dy - 0.5;
last_mn = mn;
last_dy = dy;
last_yr = yr;
last_mjd = mjd;
return(mjd);
}
/* given an mjd, return greenwich mean siderial time, gst */
double utc_gst (double mjd) {
double gst;
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;
return(gst);
}
/* given Julian Date and Longitude (decimal degrees West) compute and
* return Local Sidereal Time, in decimal hours.
*
* Provided courtesy of ecdowney@noao.edu (Elwood Downey)
*/
double sidereal (double mjd, double lng) {
double gst;
double lst;
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 = utc_gst (mjd);
lst = gst - RADHR (lng);
lst -= 24.0*floor(lst/24.0);
printf ("%7.4f\n", lst);
/* that's all */
return (lst);
}
/* Update the time dependent variables */
void fgTimeUpdate(struct FLIGHT *f, struct fgTIME *t) {
/* get current Unix calendar time (in seconds) */
t->cur_time = time(NULL);
printf("Current Unix calendar time = %ld\n", t->cur_time);
/* get GMT break down for current time */
t->gmt = gmtime(&t->cur_time);
printf("Current GMT = %d/%d/%2d %d:%02d:%02d\n",
t->gmt->tm_mon+1, t->gmt->tm_mday, t->gmt->tm_year,
t->gmt->tm_hour, t->gmt->tm_min, t->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));
/* add in partial day */
t->mjd += (t->gmt->tm_hour / 24.0) + (t->gmt->tm_min / (24.0 * 60.0)) +
(t->gmt->tm_sec / (24.0 * 60.0 * 60.0));
/* convert "back" to Julian date + partial day (as a fraction of one) */
t->jd = t->mjd + MJD0;
printf("Current Julian Date = %.5f\n", t->jd);
/* Calculate local side real time */
t->lst = sidereal(t->mjd, -(FG_Longitude * RAD_TO_DEG));
printf("Current Sidereal Time = %.3f\n", t->lst);
}
/* $Log$
/* Revision 1.2 1997/08/27 03:30:35 curt
/* Changed naming scheme of basic shared structures.
/* Revision 1.3 1997/09/13 02:00:08 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.2 1997/08/27 03:30:35 curt
* Changed naming scheme of basic shared structures.
*
* Revision 1.1 1997/08/13 21:55:59 curt
* Initial revision.
*

26
Time/fg_time.h
View file

@ -33,14 +33,24 @@
#endif
#include <GL/glut.h>
#include <time.h>
#include "../types.h"
#include "../Flight/flight.h"
/* Define a structure containing global time parameters */
struct fgTIME {
/* the point on the earth's surface above which the sun is directly
* overhead */
/* the date/time in various forms */
time_t cur_time; /* Unix "calendar" time in seconds */
struct tm *gmt; /* Break down of GMT time */
double jd; /* Julian date */
double mjd; /* modified Julian date */
double lst; /* local side real time */
/* position of the sun in various forms */
double sun_lon, sun_gc_lat; /* in geocentric coordinates */
struct fgCartesianPoint fg_sunpos; /* in cartesian coordiantes */
GLfloat sun_vec[4]; /* in view coordinates */
@ -51,13 +61,21 @@ struct fgTIME {
extern struct fgTIME cur_time_params;
/* Update the time dependent variables */
void fgTimeUpdate(struct FLIGHT *f, struct fgTIME *t);
#endif /* FG_TIME_H */
/* $Log$
/* Revision 1.3 1997/09/04 02:17:39 curt
/* Shufflin' stuff.
/* Revision 1.4 1997/09/13 02:00:08 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.3 1997/09/04 02:17:39 curt
* Shufflin' stuff.
*
* Revision 1.2 1997/08/27 03:30:36 curt
* Changed naming scheme of basic shared structures.
*

10
Time/sunpos.c
View file

@ -272,7 +272,7 @@ void fgUpdateSunPos(struct fgCartesianPoint scenery_center) {
time_warp += 0; /* increase this to make the world spin real fast */
fgSunPosition(time(NULL) + time_warp, &t->sun_lon, &sun_gd_lat);
fgSunPosition(t->cur_time + time_warp, &t->sun_lon, &sun_gd_lat);
fgGeodToGeoc(sun_gd_lat, 0.0, &sl_radius, &t->sun_gc_lat);
@ -303,9 +303,13 @@ void fgUpdateSunPos(struct fgCartesianPoint scenery_center) {
/* $Log$
/* Revision 1.9 1997/09/05 14:17:31 curt
/* More tweaking with stars.
/* Revision 1.10 1997/09/13 02:00:09 curt
/* Mostly working on stars and generating sidereal time for accurate star
/* placement.
/*
* Revision 1.9 1997/09/05 14:17:31 curt
* More tweaking with stars.
*
* Revision 1.8 1997/09/05 01:36:04 curt
* Working on getting stars right.
*