2 // fg_time.cxx -- 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)
35 #ifdef HAVE_SYS_TIMEB_H
36 # include <sys/timeb.h> // for ftime() and struct timeb
39 # include <unistd.h> // for gettimeofday()
41 #ifdef HAVE_SYS_TIME_H
42 # include <sys/time.h> // for get/setitimer, gettimeofday, struct timeval
45 #include <Debug/fg_debug.h>
46 #include <Flight/flight.h>
47 #include <Include/fg_constants.h>
48 #include <Main/options.hxx>
50 #include "fg_time.hxx"
53 #define DEGHR(x) ((x)/15.)
54 #define RADHR(x) DEGHR(x*RAD_TO_DEG)
57 struct fgTIME cur_time_params;
60 // Initialize the time dependent variables
62 void fgTimeInit(struct fgTIME *t) {
67 fgPrintf( FG_EVENT, FG_INFO, "Initializing Time\n");
69 t->gst_diff = -9999.0;
70 fgPrintf( FG_EVENT, FG_DEBUG, "o->time_offset = %d\n", o->time_offset);
72 t->warp = o->time_offset;
77 // Portability wrap to get current time.
78 void timestamp(fg_timestamp *timestamp) {
79 #if defined( HAVE_GETTIMEOFDAY )
80 struct timeval current;
82 // fg_timestamp currtime;
83 gettimeofday(¤t, &tz);
84 timestamp->seconds = current.tv_sec;
85 timestamp->millis = current.tv_usec / 1000;
86 #elif defined( HAVE_GETLOCALTIME )
88 GetLocalTime(¤t);
89 timestamp->seconds = current.wSecond;
90 timestamp->millis = current.wMilliseconds;
91 #elif defined( HAVE_FTIME )
94 timestamp->seconds = current.time;
95 timestamp->millis = current.millitm;
102 // Return duration in millis from first to last
103 long timediff(fg_timestamp *first, fg_timestamp *last) {
104 return 1000 * (last->seconds - first->seconds) +
105 (last->millis - first->millis);
109 // Return new timestamp given a time stamp and an interval to add in
110 void timesum(fg_timestamp *res, fg_timestamp *start, long millis) {
111 res->seconds = start->seconds +
112 ( start->millis + millis ) / 1000;
113 res->millis = ( start->millis + millis ) % 1000;
117 // given a date in months, mn, days, dy, years, yr, return the
118 // modified Julian date (number of days elapsed since 1900 jan 0.5),
119 // mjd. Adapted from Xephem.
121 double cal_mjd (int mn, double dy, int yr) {
122 static double last_mjd, last_dy;
124 static int last_mn, last_yr;
128 if (mn == last_mn && yr == last_yr && dy == last_dy) {
134 y = (yr < 0) ? yr + 1 : yr;
140 if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) {
149 c = (long)((365.25*y) - 0.75) - 694025L;
151 c = (long)(365.25*y) - 694025L;
154 d = (int)(30.6001*(m+1));
156 mjd = b + c + d + dy - 0.5;
167 // given an mjd, return greenwich mean siderial time, gst
169 double utc_gst (double mjd) {
171 double day = floor(mjd-0.5)+0.5;
172 double hr = (mjd-day)*24.0;
175 T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0;
176 x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T;
178 gst = (1.0/SIDRATE)*hr + x;
180 fgPrintf( FG_EVENT, FG_DEBUG, " gst => %.4f\n", gst);
186 // given Julian Date and Longitude (decimal degrees West) compute and
187 // return Local Sidereal Time, in decimal hours.
189 // Provided courtesy of ecdowney@noao.edu (Elwood Downey)
192 double sidereal_precise (double mjd, double lng) {
196 /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ",
199 // convert to required internal units
202 // compute LST and print
204 lst = gst - RADHR (lng);
205 lst -= 24.0*floor(lst/24.0);
206 // printf ("%7.4f\n", lst);
213 // return a courser but cheaper estimate of sidereal time
214 double sidereal_course(struct tm *gmt, time_t now, double lng) {
215 time_t start, start_gmt;
218 double diff, part, days, hours, lst;
220 // ftime() needs a little extra help finding the current timezone
221 #if defined( HAVE_GETTIMEOFDAY )
222 #elif defined( HAVE_GETLOCALTIME )
223 #elif defined( HAVE_FTIME )
224 struct timeb current;
232 #endif // __CYGWIN32__
235 printf(" COURSE: GMT = %d/%d/%2d %d:%02d:%02d\n",
236 gmt->tm_mon, gmt->tm_mday, gmt->tm_year,
237 gmt->tm_hour, gmt->tm_min, gmt->tm_sec);
242 mt.tm_year = gmt->tm_year;
246 mt.tm_isdst = -1; // let the system determine the proper time zone
250 /* printf("start1 = %ld\n", start);
251 fgPrintf( FG_EVENT, FG_DEBUG, "start2 = %s", ctime(&start));
252 fgPrintf( FG_EVENT, FG_DEBUG, "start3 = %ld\n", start); */
255 daylight = mt.tm_isdst;
257 // Yargs ... I'm just hardcoding this arbitrarily so it doesn't
258 // jump around for win32 people
260 fgPrintf( FG_EVENT, FG_WARN,
261 "no daylight savings info ... being hardcoded to %d\n", daylight);
264 // ftime() needs a little extra help finding the current timezone
265 #if defined( HAVE_GETTIMEOFDAY )
266 #elif defined( HAVE_GETLOCALTIME )
267 #elif defined( HAVE_FTIME )
269 timezone = current.timezone * 60;
274 if ( daylight > 0 ) {
276 } else if ( daylight < 0 ) {
277 fgPrintf( FG_EVENT, FG_WARN,
278 "OOOPS, big time problem in fg_time.c, no daylight savings info.\n");
281 offset = -(timezone / 3600 - daylight);
283 // printf(" Raw time zone offset = %ld\n", timezone);
284 // printf(" Daylight Savings = %d\n", daylight);
286 // printf(" Local hours from GMT = %ld\n", offset);
288 start_gmt = start - timezone + (daylight * 3600);
290 // printf(" March 21 noon (CST) = %ld\n", start);
291 // printf(" March 21 noon (GMT) = %ld\n", start_gmt);
293 diff = (now - start_gmt) / (3600.0 * 24.0);
295 // printf(" Time since 3/21/%2d GMT = %.2f\n", gmt->tm_year, diff);
297 part = fmod(diff, 1.0);
299 hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0;
301 lst = (days - lng)/15.0 + hours - 12;
303 while ( lst < 0.0 ) {
307 /* printf(" days = %.1f hours = %.2f lon = %.2f lst = %.2f\n",
308 days, hours, lng, lst); */
314 // Update time variables such as gmt, julian date, and sidereal time
315 void fgTimeUpdate(fgFLIGHT *f, struct fgTIME *t) {
316 double gst_precise, gst_course;
318 fgPrintf( FG_EVENT, FG_BULK, "Updating time\n");
320 // get current Unix calendar time (in seconds)
321 t->warp += t->warp_delta;
322 t->cur_time = time(NULL) + t->warp;
323 fgPrintf( FG_EVENT, FG_BULK,
324 " Current Unix calendar time = %ld warp = %ld delta = %ld\n",
325 t->cur_time, t->warp, t->warp_delta);
327 // get GMT break down for current time
328 t->gmt = gmtime(&t->cur_time);
329 fgPrintf( FG_EVENT, FG_BULK,
330 " Current GMT = %d/%d/%2d %d:%02d:%02d\n",
331 t->gmt->tm_mon+1, t->gmt->tm_mday, t->gmt->tm_year,
332 t->gmt->tm_hour, t->gmt->tm_min, t->gmt->tm_sec);
334 // calculate modified Julian date
335 t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday,
336 (int)(t->gmt->tm_year + 1900));
338 // add in partial day
339 t->mjd += (t->gmt->tm_hour / 24.0) + (t->gmt->tm_min / (24.0 * 60.0)) +
340 (t->gmt->tm_sec / (24.0 * 60.0 * 60.0));
342 // convert "back" to Julian date + partial day (as a fraction of one)
343 t->jd = t->mjd + MJD0;
344 fgPrintf( FG_EVENT, FG_BULK, " Current Julian Date = %.5f\n", t->jd);
346 // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG);
348 // Calculate local side real time
349 if ( t->gst_diff < -100.0 ) {
350 // first time through do the expensive calculation & cheap
351 // calculation to get the difference.
352 fgPrintf( FG_EVENT, FG_INFO, " First time, doing precise gst\n");
353 t->gst = gst_precise = sidereal_precise(t->mjd, 0.00);
354 gst_course = sidereal_course(t->gmt, t->cur_time, 0.00);
355 t->gst_diff = gst_precise - gst_course;
358 sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
361 // course + difference should drift off very slowly
363 sidereal_course(t->gmt, t->cur_time, 0.00) + t->gst_diff;
365 sidereal_course(t->gmt, t->cur_time, -(FG_Longitude * RAD_TO_DEG))
368 fgPrintf( FG_EVENT, FG_DEBUG,
369 " Current lon=0.00 Sidereal Time = %.3f\n", t->gst);
370 fgPrintf( FG_EVENT, FG_DEBUG,
371 " Current LOCAL Sidereal Time = %.3f (%.3f) (diff = %.3f)\n",
372 t->lst, sidereal_precise(t->mjd, -(FG_Longitude * RAD_TO_DEG)),
378 // Revision 1.3 1998/04/25 22:06:33 curt
379 // Edited cvs log messages in source files ... bad bad bad!
381 // Revision 1.2 1998/04/25 20:24:02 curt
382 // Cleaned up initialization sequence to eliminate interdependencies
383 // between sun position, lighting, and view position. This creates a
384 // valid single pass initialization path.
386 // Revision 1.1 1998/04/24 00:52:27 curt
387 // Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
389 // Separated out lighting calcs into their own file.
391 // Revision 1.41 1998/04/22 13:24:05 curt
392 // C++ - ifiing the code a bit.
393 // Starting to reorginize some of the lighting calcs to use a table lookup.
395 // Revision 1.40 1998/04/18 04:14:09 curt
396 // Moved fg_debug.c to it's own library.
398 // Revision 1.39 1998/04/09 18:40:14 curt
399 // We had unified some of the platform disparate time handling code, and
400 // there was a bug in timesum() which calculated a new time stamp based on
401 // the current time stamp + offset. This hosed the periodic event processing
402 // logic because you'd never arrive at the time the event was scheduled for.
403 // Sky updates and lighting changes are handled via this event mechanism so
404 // they never changed ... it is fixed now.
406 // Revision 1.38 1998/04/08 23:35:40 curt
407 // Tweaks to Gnu automake/autoconf system.
409 // Revision 1.37 1998/04/03 22:12:55 curt
410 // Converting to Gnu autoconf system.
411 // Centralized time handling differences.
413 // Revision 1.36 1998/03/09 22:48:09 curt
414 // Debug message tweaks.
416 // Revision 1.35 1998/02/09 15:07:52 curt
419 // Revision 1.34 1998/02/07 15:29:47 curt
420 // Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
421 // <chotchkiss@namg.us.anritsu.com>
423 // Revision 1.33 1998/02/02 20:54:04 curt
424 // Incorporated Durk's changes.
426 // Revision 1.32 1998/02/01 03:39:56 curt
429 // Revision 1.31 1998/01/27 00:48:06 curt
430 // Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
431 // system and commandline/config file processing code.
433 // Revision 1.30 1998/01/21 21:11:35 curt
436 // Revision 1.29 1998/01/19 19:27:20 curt
437 // Merged in make system changes from Bob Kuehne <rpk@sgi.com>
438 // This should simplify things tremendously.
440 // Revision 1.28 1998/01/19 18:35:49 curt
441 // Minor tweaks and fixes for cygwin32.
443 // Revision 1.27 1998/01/13 00:23:13 curt
444 // Initial changes to support loading and management of scenery tiles. Note,
445 // there's still a fair amount of work left to be done.
447 // Revision 1.26 1998/01/05 18:44:36 curt
448 // Add an option to advance/decrease time from keyboard.
450 // Revision 1.25 1997/12/31 17:46:50 curt
451 // Tweaked fg_time.c to be able to use ftime() instead of gettimeofday()
453 // Revision 1.24 1997/12/30 22:22:42 curt
454 // Further integration of event manager.
456 // Revision 1.23 1997/12/30 20:47:58 curt
457 // Integrated new event manager with subsystem initializations.
459 // Revision 1.22 1997/12/30 01:38:47 curt
460 // Switched back to per vertex normals and smooth shading for terrain.
462 // Revision 1.21 1997/12/23 04:58:39 curt
463 // Tweaked the sky coloring a bit to build in structures to allow finer rgb
466 // Revision 1.20 1997/12/15 23:55:06 curt
467 // Add xgl wrappers for debugging.
468 // Generate terrain normals on the fly.
470 // Revision 1.19 1997/12/15 20:59:10 curt
473 // Revision 1.18 1997/12/12 21:41:31 curt
474 // More light/material property tweaking ... still a ways off.
476 // Revision 1.17 1997/12/12 19:53:04 curt
477 // Working on lightling and material properties.
479 // Revision 1.16 1997/12/11 04:43:57 curt
480 // Fixed sun vector and lighting problems. I thing the moon is now lit
483 // Revision 1.15 1997/12/10 22:37:54 curt
484 // Prepended "fg" on the name of all global structures that didn't have it yet.
485 // i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
487 // Revision 1.14 1997/12/10 01:19:52 curt
488 // Tweaks for verion 0.15 release.
490 // Revision 1.13 1997/12/09 05:11:56 curt
491 // Working on tweaking lighting.
493 // Revision 1.12 1997/12/09 04:25:37 curt
494 // Working on adding a global lighting params structure.
496 // Revision 1.11 1997/11/25 19:25:40 curt
497 // Changes to integrate Durk's moon/sun code updates + clean up.
499 // Revision 1.10 1997/11/15 18:16:42 curt
502 // Revision 1.9 1997/11/14 00:26:50 curt
503 // Transform scenery coordinates earlier in pipeline when scenery is being
504 // created, not when it is being loaded. Precalculate normals for each node
505 // as average of the normals of each containing polygon so Garoude shading is
508 // Revision 1.8 1997/10/25 03:30:08 curt
511 // Revision 1.7 1997/09/23 00:29:50 curt
512 // Tweaks to get things to compile with gcc-win32.
514 // Revision 1.6 1997/09/20 03:34:34 curt
515 // Still trying to get those durned stars aligned properly.
517 // Revision 1.5 1997/09/16 22:14:52 curt
518 // Tweaked time of day lighting equations. Don't draw stars during the day.
520 // Revision 1.4 1997/09/16 15:50:31 curt
521 // Working on star alignment and time issues.
523 // Revision 1.3 1997/09/13 02:00:08 curt
524 // Mostly working on stars and generating sidereal time for accurate star
527 // Revision 1.2 1997/08/27 03:30:35 curt
528 // Changed naming scheme of basic shared structures.
530 // Revision 1.1 1997/08/13 21:55:59 curt