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
51 # include <mmsystem.h>
54 #include <Astro/sky.hxx>
55 #include <Astro/solarsystem.hxx>
56 #include <Debug/fg_debug.h>
57 #include <Flight/flight.h>
58 #include <Include/fg_constants.h>
59 #include <Main/options.hxx>
60 #include <Time/light.hxx>
62 #include "fg_time.hxx"
65 #define DEGHR(x) ((x)/15.)
66 #define RADHR(x) DEGHR(x*RAD_TO_DEG)
68 // #define MK_TIME_IS_GMT 0 // default value
69 // #define TIME_ZONE_OFFSET_WORK 0 // default value
72 fgTIME cur_time_params;
75 // Force an update of the sky and lighting parameters
76 static void local_update_sky_and_lighting_params( void ) {
78 SolarSystem::theSolarSystem->rebuild();
79 cur_light_params.Update();
84 // Initialize the time dependent variables
85 void fgTimeInit(fgTIME *t) {
86 fgPrintf( FG_EVENT, FG_INFO, "Initializing Time\n");
88 t->gst_diff = -9999.0;
90 fgPrintf( FG_EVENT, FG_DEBUG, "time offset = %d\n",
91 current_options.get_time_offset() );
93 t->warp = current_options.get_time_offset();
96 t->pause = current_options.get_pause();
100 // Portability wrap to get current time.
101 void timestamp(fg_timestamp *timestamp) {
105 timestamp->seconds = 0;
106 timestamp->millis = t;
107 #elif defined( HAVE_GETTIMEOFDAY )
108 struct timeval current;
110 // fg_timestamp currtime;
111 gettimeofday(¤t, &tz);
112 timestamp->seconds = current.tv_sec;
113 timestamp->millis = current.tv_usec / 1000;
114 #elif defined( HAVE_GETLOCALTIME )
116 GetLocalTime(¤t);
117 timestamp->seconds = current.wSecond;
118 timestamp->millis = current.wMilliseconds;
119 #elif defined( HAVE_FTIME )
120 struct timeb current;
122 timestamp->seconds = current.time;
123 timestamp->millis = current.millitm;
130 // Return duration in millis from first to last
131 long timediff(fg_timestamp *first, fg_timestamp *last) {
133 return (last->millis - first->millis);
135 return ( 1000 * (last->seconds - first->seconds) +
136 (last->millis - first->millis) );
141 // Return new timestamp given a time stamp and an interval to add in
142 void timesum(fg_timestamp *res, fg_timestamp *start, long millis) {
145 res->millis = ( start->millis + millis );
147 res->seconds = start->seconds +
148 ( start->millis + millis ) / 1000;
149 res->millis = ( start->millis + millis ) % 1000;
154 // given a date in months, mn, days, dy, years, yr, return the
155 // modified Julian date (number of days elapsed since 1900 jan 0.5),
156 // mjd. Adapted from Xephem.
158 double cal_mjd (int mn, double dy, int yr) {
159 static double last_mjd, last_dy;
161 static int last_mn, last_yr;
165 if (mn == last_mn && yr == last_yr && dy == last_dy) {
171 y = (yr < 0) ? yr + 1 : yr;
177 if (yr < 1582 || (yr == 1582 && (mn < 10 || (mn == 10 && dy < 15)))) {
186 c = (long)((365.25*y) - 0.75) - 694025L;
188 c = (long)(365.25*y) - 694025L;
191 d = (int)(30.6001*(m+1));
193 mjd = b + c + d + dy - 0.5;
204 // given an mjd, return greenwich mean sidereal time, gst
206 double utc_gst (double mjd) {
208 double day = floor(mjd-0.5)+0.5;
209 double hr = (mjd-day)*24.0;
212 T = ((int)(mjd - 0.5) + 0.5 - J2000)/36525.0;
213 x = 24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * T) * T) * T;
215 gst = (1.0/SIDRATE)*hr + x;
217 fgPrintf( FG_EVENT, FG_DEBUG, " gst => %.4f\n", gst);
223 // given Julian Date and Longitude (decimal degrees West) compute and
224 // return Local Sidereal Time, in decimal hours.
226 // Provided courtesy of ecdowney@noao.edu (Elwood Downey)
229 double sidereal_precise (double mjd, double lng) {
233 /* printf ("Current Lst on JD %13.5f at %8.4f degrees West: ",
236 // convert to required internal units
239 // compute LST and print
241 lst = gst - RADHR (lng);
242 lst -= 24.0*floor(lst/24.0);
243 // printf ("%7.4f\n", lst);
250 // Fix up timezone if using ftime()
251 long int fix_up_timezone( long int timezone_orig ) {
252 #if !defined( HAVE_GETTIMEOFDAY ) && defined( HAVE_FTIME )
253 // ftime() needs a little extra help finding the current timezone
254 struct timeb current;
256 return( current.timezone * 60 );
258 return( timezone_orig );
263 // Return time_t for Sat Mar 21 12:00:00 GMT
265 // I believe the mktime() has a SYSV vs. BSD behavior difference.
267 // The BSD style mktime() is nice because it returns its result
268 // assuming you have specified the input time in GMT
270 // The SYSV style mktime() is a pain because it returns its result
271 // assuming you have specified the input time in your local timezone.
272 // Therefore you have to go to extra trouble to convert back to GMT.
274 // If you are having problems with incorrectly positioned astronomical
275 // bodies, this is a really good place to start looking.
277 time_t get_start_gmt(int year) {
280 // For now we assume that if daylight is not defined in
281 // /usr/include/time.h that we have a machine with a BSD behaving
283 # if !defined(HAVE_DAYLIGHT)
284 # define MK_TIME_IS_GMT 1
287 // timezone seems to work as a proper offset for Linux & Solaris
288 # if defined( __linux__ ) || defined( __sun__ )
289 # define TIMEZONE_OFFSET_WORKS 1
298 mt.tm_isdst = -1; // let the system determine the proper time zone
300 # if defined( MK_TIME_IS_GMT )
301 return ( mktime(&mt) );
302 # else // ! defined ( MK_TIME_IS_GMT )
304 long int start = mktime(&mt);
306 fgPrintf( FG_EVENT, FG_DEBUG, "start1 = %ld\n", start);
307 // the ctime() call can screw up time progression on some versions
309 // fgPrintf( FG_EVENT, FG_DEBUG, "start2 = %s", ctime(&start));
310 fgPrintf( FG_EVENT, FG_DEBUG, "(tm_isdst = %d)\n", mt.tm_isdst);
312 timezone = fix_up_timezone( timezone );
314 # if defined( TIMEZONE_OFFSET_WORKS )
315 fgPrintf( FG_EVENT, FG_DEBUG,
316 "start = %ld, timezone = %ld\n", start, timezone );
317 return( start - timezone );
318 # else // ! defined( TIMEZONE_OFFSET_WORKS )
320 daylight = mt.tm_isdst;
321 if ( daylight > 0 ) {
323 } else if ( daylight < 0 ) {
324 fgPrintf( FG_EVENT, FG_WARN,
325 "OOOPS, problem in fg_time.cxx, no daylight savings info.\n");
328 long int offset = -(timezone / 3600 - daylight);
330 fgPrintf( FG_EVENT, FG_DEBUG,
331 " Raw time zone offset = %ld\n", timezone);
332 fgPrintf( FG_EVENT, FG_DEBUG,
333 " Daylight Savings = %d\n", daylight);
334 fgPrintf( FG_EVENT, FG_DEBUG,
335 " Local hours from GMT = %ld\n", offset);
337 long int start_gmt = start - timezone + (daylight * 3600);
339 fgPrintf( FG_EVENT, FG_DEBUG, " March 21 noon (CST) = %ld\n", start);
341 return ( start_gmt );
342 # endif // ! defined( TIMEZONE_OFFSET_WORKS )
343 # endif // ! defined ( MK_TIME_IS_GMT )
347 // return a courser but cheaper estimate of sidereal time
348 double sidereal_course(fgTIME *t, double lng) {
350 time_t start_gmt, now;
351 double diff, part, days, hours, lst;
355 start_gmt = get_start_gmt(gmt->tm_year);
357 fgPrintf(FG_EVENT, FG_DEBUG,
358 " COURSE: GMT = %d/%d/%2d %d:%02d:%02d\n",
359 gmt->tm_mon, gmt->tm_mday, gmt->tm_year,
360 gmt->tm_hour, gmt->tm_min, gmt->tm_sec);
362 fgPrintf( FG_EVENT, FG_DEBUG, " March 21 noon (GMT) = %ld\n", start_gmt);
364 diff = (now - start_gmt) / (3600.0 * 24.0);
366 fgPrintf( FG_EVENT, FG_DEBUG,
367 " Time since 3/21/%2d GMT = %.2f\n", gmt->tm_year, diff);
369 part = fmod(diff, 1.0);
371 hours = gmt->tm_hour + gmt->tm_min/60.0 + gmt->tm_sec/3600.0;
373 lst = (days - lng)/15.0 + hours - 12;
375 while ( lst < 0.0 ) {
379 fgPrintf( FG_EVENT, FG_DEBUG,
380 " days = %.1f hours = %.2f lon = %.2f lst = %.2f\n",
381 days, hours, lng, lst);
387 // Update time variables such as gmt, julian date, and sidereal time
388 void fgTimeUpdate(fgFLIGHT *f, fgTIME *t) {
389 double gst_precise, gst_course;
391 fgPrintf( FG_EVENT, FG_BULK, "Updating time\n");
393 // get current Unix calendar time (in seconds)
394 t->warp += t->warp_delta;
395 t->cur_time = time(NULL) + t->warp;
396 fgPrintf( FG_EVENT, FG_BULK,
397 " Current Unix calendar time = %ld warp = %ld delta = %ld\n",
398 t->cur_time, t->warp, t->warp_delta);
400 if ( t->warp_delta ) {
401 // time is changing so force an update
402 local_update_sky_and_lighting_params();
405 // get GMT break down for current time
406 t->gmt = gmtime(&t->cur_time);
407 fgPrintf( FG_EVENT, FG_BULK,
408 " Current GMT = %d/%d/%2d %d:%02d:%02d\n",
409 t->gmt->tm_mon+1, t->gmt->tm_mday, t->gmt->tm_year,
410 t->gmt->tm_hour, t->gmt->tm_min, t->gmt->tm_sec);
412 // calculate modified Julian date
413 t->mjd = cal_mjd ((int)(t->gmt->tm_mon+1), (double)t->gmt->tm_mday,
414 (int)(t->gmt->tm_year + 1900));
416 // add in partial day
417 t->mjd += (t->gmt->tm_hour / 24.0) + (t->gmt->tm_min / (24.0 * 60.0)) +
418 (t->gmt->tm_sec / (24.0 * 60.0 * 60.0));
420 // convert "back" to Julian date + partial day (as a fraction of one)
421 t->jd = t->mjd + MJD0;
422 fgPrintf( FG_EVENT, FG_BULK, " Current Julian Date = %.5f\n", t->jd);
424 // printf(" Current Longitude = %.3f\n", FG_Longitude * RAD_TO_DEG);
426 // Calculate local side real time
427 if ( t->gst_diff < -100.0 ) {
428 // first time through do the expensive calculation & cheap
429 // calculation to get the difference.
430 fgPrintf( FG_EVENT, FG_INFO, " First time, doing precise gst\n");
431 t->gst = gst_precise = sidereal_precise(t->mjd, 0.00);
432 gst_course = sidereal_course(t, 0.00);
433 t->gst_diff = gst_precise - gst_course;
435 t->lst = sidereal_course(t, -(FG_Longitude * RAD_TO_DEG)) + t->gst_diff;
437 // course + difference should drift off very slowly
438 t->gst = sidereal_course(t, 0.00) + t->gst_diff;
439 t->lst = sidereal_course(t, -(FG_Longitude * RAD_TO_DEG)) + t->gst_diff;
441 fgPrintf( FG_EVENT, FG_DEBUG,
442 " Current lon=0.00 Sidereal Time = %.3f\n", t->gst);
443 fgPrintf( FG_EVENT, FG_DEBUG,
444 " Current LOCAL Sidereal Time = %.3f (%.3f) (diff = %.3f)\n",
445 t->lst, sidereal_precise(t->mjd, -(FG_Longitude * RAD_TO_DEG)),
451 // Revision 1.18 1998/10/02 21:36:09 curt
452 // Fixes to try to break through the win95/98 18.3 fps barrier.
454 // Revision 1.17 1998/09/15 04:27:49 curt
455 // Changes for new astro code.
457 // Revision 1.16 1998/08/29 13:11:32 curt
458 // Bernie Bright writes:
459 // I've created some new classes to enable pointers-to-functions and
460 // pointers-to-class-methods to be treated like objects. These objects
461 // can be registered with fgEVENT_MGR.
463 // File "Include/fg_callback.hxx" contains the callback class defns.
465 // Modified fgEVENT and fgEVENT_MGR to use the callback classes. Also
466 // some minor tweaks to STL usage.
468 // Added file "Include/fg_stl_config.h" to deal with STL portability
469 // issues. I've added an initial config for egcs (and probably gcc-2.8.x).
470 // I don't have access to Visual C++ so I've left that for someone else.
471 // This file is influenced by the stl_config.h file delivered with egcs.
473 // Added "Include/auto_ptr.hxx" which contains an implementation of the
474 // STL auto_ptr class which is not provided in all STL implementations
475 // and is needed to use the callback classes.
477 // Deleted fgLightUpdate() which was just a wrapper to call
478 // fgLIGHT::Update().
480 // Modified fg_init.cxx to register two method callbacks in place of the
481 // old wrapper functions.
483 // Revision 1.15 1998/08/24 20:12:16 curt
484 // Rewrote sidereal_course with simpler parameters.
486 // Revision 1.14 1998/08/05 00:20:07 curt
487 // Added a local routine to update lighting params every frame when time is
490 // Revision 1.13 1998/07/30 23:48:55 curt
494 // Revision 1.12 1998/07/27 18:42:22 curt
495 // Added a pause option.
497 // Revision 1.11 1998/07/22 21:45:37 curt
498 // fg_time.cxx: Removed call to ctime() in a printf() which should be harmless
499 // but seems to be triggering a bug.
500 // light.cxx: Added code to adjust fog color based on sunrise/sunset effects
501 // and view orientation. This is an attempt to match the fog color to the
502 // sky color in the center of the screen. You see discrepancies at the
503 // edges, but what else can be done?
504 // sunpos.cxx: Caculate local direction to sun here. (what compass direction
505 // do we need to face to point directly at sun)
507 // Revision 1.10 1998/07/13 21:02:07 curt
508 // Wrote access functions for current fgOPTIONS.
510 // Revision 1.9 1998/06/12 00:59:53 curt
511 // Build only static libraries.
512 // Declare memmove/memset for Sloaris.
513 // Rewrote fg_time.c routine to get LST start seconds to better handle
514 // Solaris, and be easier to port, and understand the GMT vs. local
517 // Revision 1.8 1998/06/05 18:18:13 curt
518 // Incorporated some automake conditionals to try to support mktime() correctly
519 // on a wider variety of platforms.
520 // Added the declaration of memmove needed by the stl which apparently
521 // solaris only defines for cc compilations and not for c++ (__STDC__)
523 // Revision 1.7 1998/05/30 01:57:25 curt
526 // Revision 1.6 1998/05/02 01:53:17 curt
527 // Fine tuning mktime() support because of varying behavior on different
530 // Revision 1.5 1998/04/28 21:45:34 curt
531 // Fixed a horible bug that cause the time to be *WAY* off when compiling
532 // with the CygWin32 compiler. This may not yet completely address other
533 // Win32 compilers, but we'll have to take them on a case by case basis.
535 // Revision 1.4 1998/04/28 01:22:16 curt
536 // Type-ified fgTIME and fgVIEW.
538 // Revision 1.3 1998/04/25 22:06:33 curt
539 // Edited cvs log messages in source files ... bad bad bad!
541 // Revision 1.2 1998/04/25 20:24:02 curt
542 // Cleaned up initialization sequence to eliminate interdependencies
543 // between sun position, lighting, and view position. This creates a
544 // valid single pass initialization path.
546 // Revision 1.1 1998/04/24 00:52:27 curt
547 // Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
549 // Separated out lighting calcs into their own file.
551 // Revision 1.41 1998/04/22 13:24:05 curt
552 // C++ - ifiing the code a bit.
553 // Starting to reorginize some of the lighting calcs to use a table lookup.
555 // Revision 1.40 1998/04/18 04:14:09 curt
556 // Moved fg_debug.c to it's own library.
558 // Revision 1.39 1998/04/09 18:40:14 curt
559 // We had unified some of the platform disparate time handling code, and
560 // there was a bug in timesum() which calculated a new time stamp based on
561 // the current time stamp + offset. This hosed the periodic event processing
562 // logic because you'd never arrive at the time the event was scheduled for.
563 // Sky updates and lighting changes are handled via this event mechanism so
564 // they never changed ... it is fixed now.
566 // Revision 1.38 1998/04/08 23:35:40 curt
567 // Tweaks to Gnu automake/autoconf system.
569 // Revision 1.37 1998/04/03 22:12:55 curt
570 // Converting to Gnu autoconf system.
571 // Centralized time handling differences.
573 // Revision 1.36 1998/03/09 22:48:09 curt
574 // Debug message tweaks.
576 // Revision 1.35 1998/02/09 15:07:52 curt
579 // Revision 1.34 1998/02/07 15:29:47 curt
580 // Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
581 // <chotchkiss@namg.us.anritsu.com>
583 // Revision 1.33 1998/02/02 20:54:04 curt
584 // Incorporated Durk's changes.
586 // Revision 1.32 1998/02/01 03:39:56 curt
589 // Revision 1.31 1998/01/27 00:48:06 curt
590 // Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
591 // system and commandline/config file processing code.
593 // Revision 1.30 1998/01/21 21:11:35 curt
596 // Revision 1.29 1998/01/19 19:27:20 curt
597 // Merged in make system changes from Bob Kuehne <rpk@sgi.com>
598 // This should simplify things tremendously.
600 // Revision 1.28 1998/01/19 18:35:49 curt
601 // Minor tweaks and fixes for cygwin32.
603 // Revision 1.27 1998/01/13 00:23:13 curt
604 // Initial changes to support loading and management of scenery tiles. Note,
605 // there's still a fair amount of work left to be done.
607 // Revision 1.26 1998/01/05 18:44:36 curt
608 // Add an option to advance/decrease time from keyboard.
610 // Revision 1.25 1997/12/31 17:46:50 curt
611 // Tweaked fg_time.c to be able to use ftime() instead of gettimeofday()
613 // Revision 1.24 1997/12/30 22:22:42 curt
614 // Further integration of event manager.
616 // Revision 1.23 1997/12/30 20:47:58 curt
617 // Integrated new event manager with subsystem initializations.
619 // Revision 1.22 1997/12/30 01:38:47 curt
620 // Switched back to per vertex normals and smooth shading for terrain.
622 // Revision 1.21 1997/12/23 04:58:39 curt
623 // Tweaked the sky coloring a bit to build in structures to allow finer rgb
626 // Revision 1.20 1997/12/15 23:55:06 curt
627 // Add xgl wrappers for debugging.
628 // Generate terrain normals on the fly.
630 // Revision 1.19 1997/12/15 20:59:10 curt
633 // Revision 1.18 1997/12/12 21:41:31 curt
634 // More light/material property tweaking ... still a ways off.
636 // Revision 1.17 1997/12/12 19:53:04 curt
637 // Working on lightling and material properties.
639 // Revision 1.16 1997/12/11 04:43:57 curt
640 // Fixed sun vector and lighting problems. I thing the moon is now lit
643 // Revision 1.15 1997/12/10 22:37:54 curt
644 // Prepended "fg" on the name of all global structures that didn't have it yet.
645 // i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
647 // Revision 1.14 1997/12/10 01:19:52 curt
648 // Tweaks for verion 0.15 release.
650 // Revision 1.13 1997/12/09 05:11:56 curt
651 // Working on tweaking lighting.
653 // Revision 1.12 1997/12/09 04:25:37 curt
654 // Working on adding a global lighting params structure.
656 // Revision 1.11 1997/11/25 19:25:40 curt
657 // Changes to integrate Durk's moon/sun code updates + clean up.
659 // Revision 1.10 1997/11/15 18:16:42 curt
662 // Revision 1.9 1997/11/14 00:26:50 curt
663 // Transform scenery coordinates earlier in pipeline when scenery is being
664 // created, not when it is being loaded. Precalculate normals for each node
665 // as average of the normals of each containing polygon so Garoude shading is
668 // Revision 1.8 1997/10/25 03:30:08 curt
671 // Revision 1.7 1997/09/23 00:29:50 curt
672 // Tweaks to get things to compile with gcc-win32.
674 // Revision 1.6 1997/09/20 03:34:34 curt
675 // Still trying to get those durned stars aligned properly.
677 // Revision 1.5 1997/09/16 22:14:52 curt
678 // Tweaked time of day lighting equations. Don't draw stars during the day.
680 // Revision 1.4 1997/09/16 15:50:31 curt
681 // Working on star alignment and time issues.
683 // Revision 1.3 1997/09/13 02:00:08 curt
684 // Mostly working on stars and generating sidereal time for accurate star
687 // Revision 1.2 1997/08/27 03:30:35 curt
688 // Changed naming scheme of basic shared structures.
690 // Revision 1.1 1997/08/13 21:55:59 curt