1 /**************************************************************************
2 * fg_time.c -- data structures and routines for managing time related stuff.
4 * Written by Curtis Olson, started August 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of the
11 * License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 * (Log is kept at end of this file)
24 **************************************************************************/
34 #ifdef HAVE_SYS_TIMEB_H
35 # include <sys/timeb.h> /* for ftime() and struct timeb */
38 # include <unistd.h> /* for gettimeofday() */
40 #ifdef HAVE_SYS_TIME_H
41 # include <sys/time.h> /* for get/setitimer, gettimeofday, struct timeval */
44 #include <Time/fg_time.h>
45 #include <Include/fg_constants.h>
46 #include <Flight/flight.h>
49 #define DEGHR(x) ((x)/15.)
50 #define RADHR(x) DEGHR(x*RAD_TO_DEG)
52 #include <Main/fg_debug.h>
54 struct fgTIME cur_time_params;
55 struct fgLIGHT cur_light_params;
58 /* Initialize the time dependent variables */
60 void fgTimeInit(struct fgTIME *t) {
61 fgPrintf( FG_EVENT, FG_INFO, "Initializing Time\n");
63 t->gst_diff = -9999.0;
69 /* Portability wrap to get current time. */
70 void timestamp(fg_timestamp *timestamp) {
71 #if defined( HAVE_GETTIMEOFDAY )
72 struct timeval current;
74 fg_timestamp currtime;
75 gettimeofday(¤t, &tz);
76 timestamp->seconds = current.tv_sec;
77 timestamp->millis = current.tv_usec / 1000;
78 #elif defined( HAVE_GETLOCALTIME )
80 GetLocalTime(¤t);
81 timestamp->seconds = current.wSecond;
82 timestamp->millis = current.wMilliseconds;
83 #elif defined( HAVE_FTIME )
86 timestamp->seconds = current.time;
87 timestamp->millis = current.millitm;
94 /* Return duration in millis from first to last */
95 long timediff(fg_timestamp *first, fg_timestamp *last) {
96 return 1000 * (last->seconds - first->seconds) +
97 (last->millis - first->millis);
101 /* Return new timestamp given a time stamp and an interval to add in */
102 void timesum(fg_timestamp *res, fg_timestamp *start, long millis) {
103 res->millis = start->millis + millis;
104 if (1000 < res->millis) {
105 res->seconds = start->millis + 1;
108 res->seconds = start->millis;
113 /* given a date in months, mn, days, dy, years, yr, return the
114 * modified Julian date (number of days elapsed since 1900 jan 0.5),
115 * mjd. Adapted from Xephem. */
117 double cal_mjd (int mn, double dy, int yr) {
118 static double last_mjd, last_dy;
120 static int last_mn, last_yr;
124 if (mn == last_mn && yr == last_yr && dy == last_dy) {
130 y = (yr < 0) ? yr + 1 : yr;
136 if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) {
145 c = (long)((365.25*y) - 0.75) - 694025L;
147 c = (long)(365.25*y) - 694025L;
150 d = (int)(30.6001*(m+1));
152 mjd = b + c + d + dy - 0.5;
163 /* given an mjd, return greenwich mean siderial time, gst */
165 double utc_gst (double mjd) {
167 double day = floor(mjd-0.5)+0.5;
168 double hr = (mjd-day)*24.0;
171 T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0;
172 x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T;
174 gst = (1.0/SIDRATE)*hr + x;
176 fgPrintf( FG_EVENT, FG_DEBUG, " gst => %.4f\n", gst);
182 /* given Julian Date and Longitude (decimal degrees West) compute and
183 * return Local Sidereal Time, in decimal hours.
185 * Provided courtesy of ecdowney@noao.edu (Elwood Downey)
188 double sidereal_precise (double mjd, double lng) {
192 /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ",
195 /* convert to required internal units */
198 /* compute LST and print */
200 lst = gst - RADHR (lng);
201 lst -= 24.0*floor(lst/24.0);
202 /* printf ("%7.4f\n", lst); */
209 /* return a courser but cheaper estimate of sidereal time */
210 double sidereal_course(struct tm *gmt, time_t now, double lng) {
211 time_t start, start_gmt;
214 double diff, part, days, hours, lst;
217 struct timeb current;
218 #endif /* USE_FTIME */
226 printf(" COURSE: GMT = %d/%d/%2d %d:%02d:%02d\n",
227 gmt->tm_mon, gmt->tm_mday, gmt->tm_year,
228 gmt->tm_hour, gmt->tm_min, gmt->tm_sec);
233 mt.tm_year = gmt->tm_year;
237 mt.tm_isdst = -1; /* let the system determine the proper time zone */
241 /* printf("start1 = %ld\n", start);
242 fgPrintf( FG_EVENT, FG_DEBUG, "start2 = %s", ctime(&start));
243 fgPrintf( FG_EVENT, FG_DEBUG, "start3 = %ld\n", start); */
246 daylight = mt.tm_isdst;
248 /* Yargs ... I'm just hardcoding this arbitrarily so it doesn't
251 fgPrintf( FG_EVENT, FG_WARN,
252 "no daylight savings info ... being hardcoded to %d\n", daylight);
257 timezone = current.timezone * 60;
258 #endif /* USE_FTIME */
260 if ( daylight > 0 ) {
262 } else if ( daylight < 0 ) {
263 fgPrintf( FG_EVENT, FG_WARN,
264 "OOOPS, big time problem in fg_time.c, no daylight savings info.\n");
267 offset = -(timezone / 3600 - daylight);
269 /* printf(" Raw time zone offset = %ld\n", timezone); */
270 /* printf(" Daylight Savings = %d\n", daylight); */
272 /* printf(" Local hours from GMT = %ld\n", offset); */
274 start_gmt = start - timezone + (daylight * 3600);
276 /* printf(" March 21 noon (CST) = %ld\n", start); */
277 /* printf(" March 21 noon (GMT) = %ld\n", start_gmt); */
279 diff = (now - start_gmt) / (3600.0 * 24.0);
281 /* printf(" Time since 3/21/%2d GMT = %.2f\n", gmt->tm_year, diff); */
283 part = fmod(diff, 1.0);
285 hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0;
287 lst = (days - lng)/15.0 + hours - 12;
289 while ( lst < 0.0 ) {
293 /* printf(" days = %.1f hours = %.2f lon = %.2f lst = %.2f\n",
294 days, hours, lng, lst); */
300 /* Update the time dependent variables */
302 void fgTimeUpdate(fgFLIGHT *f, struct fgTIME *t) {
303 double gst_precise, gst_course;
305 fgPrintf( FG_EVENT, FG_BULK, "Updating time\n");
307 /* get current Unix calendar time (in seconds) */
308 t->warp += t->warp_delta;
309 t->cur_time = time(NULL) + t->warp;
310 fgPrintf( FG_EVENT, FG_BULK,
311 " Current Unix calendar time = %ld warp = %ld delta = %ld\n",
312 t->cur_time, t->warp, t->warp_delta);
314 /* get GMT break down for current time */
315 t->gmt = gmtime(&t->cur_time);
316 fgPrintf( FG_EVENT, FG_BULK,
317 " Current GMT = %d/%d/%2d %d:%02d:%02d\n",
318 t->gmt->tm_mon+1, t->gmt->tm_mday, t->gmt->tm_year,
319 t->gmt->tm_hour, t->gmt->tm_min, t->gmt->tm_sec);
321 /* calculate modified Julian date */
322 t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday,
323 (int)(t->gmt->tm_year + 1900));
325 /* add in partial day */
326 t->mjd += (t->gmt->tm_hour / 24.0) + (t->gmt->tm_min / (24.0 * 60.0)) +
327 (t->gmt->tm_sec / (24.0 * 60.0 * 60.0));
329 /* convert "back" to Julian date + partial day (as a fraction of one) */
330 t->jd = t->mjd + MJD0;
331 fgPrintf( FG_EVENT, FG_BULK, " Current Julian Date = %.5f\n", t->jd);
333 /* printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG); */
335 /* Calculate local side real time */
336 if ( t->gst_diff < -100.0 ) {
337 /* first time through do the expensive calculation & cheap
338 calculation to get the difference. */
339 fgPrintf( FG_EVENT, FG_INFO, " First time, doing precise gst\n");
340 t->gst = gst_precise = sidereal_precise(t->mjd, 0.00);
341 gst_course = sidereal_course(t->gmt, t->cur_time, 0.00);
342 t->gst_diff = gst_precise - gst_course;
345 sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
348 /* course + difference should drift off very slowly */
350 sidereal_course(t->gmt, t->cur_time, 0.00) + t->gst_diff;
352 sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
355 fgPrintf( FG_EVENT, FG_DEBUG,
356 " Current lon=0.00 Sidereal Time = %.3f\n", t->gst);
357 fgPrintf( FG_EVENT, FG_DEBUG,
358 " Current LOCAL Sidereal Time = %.3f (%.3f) (diff = %.3f)\n",
359 t->lst, sidereal_precise(t->mjd, -(FG_Longitude * RAD_TO_DEG)),
365 /* Revision 1.37 1998/04/03 22:12:55 curt
366 /* Converting to Gnu autoconf system.
367 /* Centralized time handling differences.
369 * Revision 1.36 1998/03/09 22:48:09 curt
370 * Debug message tweaks.
372 * Revision 1.35 1998/02/09 15:07:52 curt
375 * Revision 1.34 1998/02/07 15:29:47 curt
376 * Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
377 * <chotchkiss@namg.us.anritsu.com>
379 * Revision 1.33 1998/02/02 20:54:04 curt
380 * Incorporated Durk's changes.
382 * Revision 1.32 1998/02/01 03:39:56 curt
385 * Revision 1.31 1998/01/27 00:48:06 curt
386 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
387 * system and commandline/config file processing code.
389 * Revision 1.30 1998/01/21 21:11:35 curt
392 * Revision 1.29 1998/01/19 19:27:20 curt
393 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
394 * This should simplify things tremendously.
396 * Revision 1.28 1998/01/19 18:35:49 curt
397 * Minor tweaks and fixes for cygwin32.
399 * Revision 1.27 1998/01/13 00:23:13 curt
400 * Initial changes to support loading and management of scenery tiles. Note,
401 * there's still a fair amount of work left to be done.
403 * Revision 1.26 1998/01/05 18:44:36 curt
404 * Add an option to advance/decrease time from keyboard.
406 * Revision 1.25 1997/12/31 17:46:50 curt
407 * Tweaked fg_time.c to be able to use ftime() instead of gettimeofday()
409 * Revision 1.24 1997/12/30 22:22:42 curt
410 * Further integration of event manager.
412 * Revision 1.23 1997/12/30 20:47:58 curt
413 * Integrated new event manager with subsystem initializations.
415 * Revision 1.22 1997/12/30 01:38:47 curt
416 * Switched back to per vertex normals and smooth shading for terrain.
418 * Revision 1.21 1997/12/23 04:58:39 curt
419 * Tweaked the sky coloring a bit to build in structures to allow finer rgb
422 * Revision 1.20 1997/12/15 23:55:06 curt
423 * Add xgl wrappers for debugging.
424 * Generate terrain normals on the fly.
426 * Revision 1.19 1997/12/15 20:59:10 curt
429 * Revision 1.18 1997/12/12 21:41:31 curt
430 * More light/material property tweaking ... still a ways off.
432 * Revision 1.17 1997/12/12 19:53:04 curt
433 * Working on lightling and material properties.
435 * Revision 1.16 1997/12/11 04:43:57 curt
436 * Fixed sun vector and lighting problems. I thing the moon is now lit
439 * Revision 1.15 1997/12/10 22:37:54 curt
440 * Prepended "fg" on the name of all global structures that didn't have it yet.
441 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
443 * Revision 1.14 1997/12/10 01:19:52 curt
444 * Tweaks for verion 0.15 release.
446 * Revision 1.13 1997/12/09 05:11:56 curt
447 * Working on tweaking lighting.
449 * Revision 1.12 1997/12/09 04:25:37 curt
450 * Working on adding a global lighting params structure.
452 * Revision 1.11 1997/11/25 19:25:40 curt
453 * Changes to integrate Durk's moon/sun code updates + clean up.
455 * Revision 1.10 1997/11/15 18:16:42 curt
458 * Revision 1.9 1997/11/14 00:26:50 curt
459 * Transform scenery coordinates earlier in pipeline when scenery is being
460 * created, not when it is being loaded. Precalculate normals for each node
461 * as average of the normals of each containing polygon so Garoude shading is
464 * Revision 1.8 1997/10/25 03:30:08 curt
467 * Revision 1.7 1997/09/23 00:29:50 curt
468 * Tweaks to get things to compile with gcc-win32.
470 * Revision 1.6 1997/09/20 03:34:34 curt
471 * Still trying to get those durned stars aligned properly.
473 * Revision 1.5 1997/09/16 22:14:52 curt
474 * Tweaked time of day lighting equations. Don't draw stars during the day.
476 * Revision 1.4 1997/09/16 15:50:31 curt
477 * Working on star alignment and time issues.
479 * Revision 1.3 1997/09/13 02:00:08 curt
480 * Mostly working on stars and generating sidereal time for accurate star
483 * Revision 1.2 1997/08/27 03:30:35 curt
484 * Changed naming scheme of basic shared structures.
486 * Revision 1.1 1997/08/13 21:55:59 curt