1 // TimeManager.cxx -- simulation-wide time management
3 // Written by James Turner, started July 2010.
5 // Copyright (C) 2010 Curtis L. Olson - http://www.flightgear.org/~curt
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 #include "TimeManager.hxx"
28 # define WIN32_LEAN_AND_MEAN
29 # include <windows.h> // for Sleep()
31 # include <unistd.h> // for usleep()
34 #include <simgear/timing/sg_time.hxx>
35 #include <simgear/structure/event_mgr.hxx>
36 #include <simgear/misc/sg_path.hxx>
37 #include <simgear/timing/lowleveltime.h>
38 #include <simgear/structure/commands.hxx>
40 #include <Main/fg_props.hxx>
41 #include <Main/globals.hxx>
42 #include <Time/sunsolver.hxx>
46 static bool do_timeofday (const SGPropertyNode * arg)
48 const string &offset_type = arg->getStringValue("timeofday", "noon");
49 int offset = arg->getIntValue("offset", 0);
50 TimeManager* self = (TimeManager*) globals->get_subsystem("time");
51 if (offset_type == "real") {
52 // without this, setting 'real' time is a no-op, since the current
53 // wrap value (orig_warp) is retained in setTimeOffset. Ick.
54 fgSetInt("/sim/time/warp", 0);
57 self->setTimeOffset(offset_type, offset);
61 TimeManager::TimeManager() :
65 SGCommandMgr::instance()->addCommand("timeofday", do_timeofday);
68 void TimeManager::init()
71 // time manager has to be initialised early, so needs to be defensive
72 // about multiple initialisation
79 _adjustWarpOnUnfreeze = false;
81 _maxDtPerFrame = fgGetNode("/sim/max-simtime-per-frame", true);
82 _clockFreeze = fgGetNode("/sim/freeze/clock", true);
83 _timeOverride = fgGetNode("/sim/time/cur-time-override", true);
84 _warp = fgGetNode("/sim/time/warp", true);
85 _warp->addChangeListener(this);
87 _warpDelta = fgGetNode("/sim/time/warp-delta", true);
89 _longitudeDeg = fgGetNode("/position/longitude-deg", true);
90 _latitudeDeg = fgGetNode("/position/latitude-deg", true);
92 SGPath zone(globals->get_fg_root());
93 zone.append("Timezone");
94 double lon = _longitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
95 double lat = _latitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
97 _impl = new SGTime(lon, lat, zone.str(), _timeOverride->getLongValue());
99 _warpDelta->setIntValue(0);
101 globals->get_event_mgr()->addTask("updateLocalTime", this,
102 &TimeManager::updateLocalTime, 30*60 );
105 _impl->update(lon, lat, _timeOverride->getLongValue(),
106 _warp->getIntValue());
107 globals->set_time_params(_impl);
109 // frame-rate / worst-case latency / update-rate counters
110 _frameRate = fgGetNode("/sim/frame-rate", true);
111 _frameLatency = fgGetNode("/sim/frame-latency-max-ms", true);
113 _frameLatencyMax = 0.0;
117 void TimeManager::postinit()
122 void TimeManager::reinit()
129 void TimeManager::shutdown()
131 _warp->removeChangeListener(this);
133 globals->set_time_params(NULL);
137 globals->get_event_mgr()->removeTask("updateLocalTime");
140 void TimeManager::valueChanged(SGPropertyNode* aProp)
142 if (aProp == _warp) {
143 if (_clockFreeze->getBoolValue()) {
144 // if the warp is changed manually while frozen, don't modify it when
145 // un-freezing - the user wants to unfreeze with exactly the warp
147 _adjustWarpOnUnfreeze = false;
150 double lon = _longitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
151 double lat = _latitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
152 _impl->update(lon, lat,
153 _timeOverride->getLongValue(),
154 _warp->getIntValue());
158 void TimeManager::computeTimeDeltas(double& simDt, double& realDt)
160 // Update the elapsed time.
163 _firstUpdate = false;
164 _lastClockFreeze = _clockFreeze->getBoolValue();
167 bool scenery_loaded = fgGetBool("sim/sceneryloaded");
168 bool wait_for_scenery = !(scenery_loaded || fgGetBool("sim/sceneryloaded-override"));
170 if (!wait_for_scenery) {
171 throttleUpdateRate();
175 // suppress framerate while initial scenery isn't loaded yet (splash screen still active)
180 SGTimeStamp currentStamp;
181 currentStamp.stamp();
182 double dt = (currentStamp - _lastStamp).toSecs();
183 if (dt > _frameLatencyMax)
184 _frameLatencyMax = dt;
186 // Limit the time we need to spend in simulation loops
187 // That means, if the /sim/max-simtime-per-frame value is strictly positive
188 // you can limit the maximum amount of time you will do simulations for
189 // one frame to display. The cpu time spent in simulations code is roughly
190 // at least O(real_delta_time_sec). If this is (due to running debug
191 // builds or valgrind or something different blowing up execution times)
192 // larger than the real time you will no longer get any response
193 // from flightgear. This limits that effect. Just set to property from
194 // your .fgfsrc or commandline ...
195 double dtMax = _maxDtPerFrame->getDoubleValue();
196 if (0 < dtMax && dtMax < dt) {
200 int model_hz = fgGetInt("/sim/model-hz");
202 SGSubsystemGroup* fdmGroup =
203 globals->get_subsystem_mgr()->get_group(SGSubsystemMgr::FDM);
204 fdmGroup->set_fixed_update_time(1.0 / model_hz);
206 // round the real time down to a multiple of 1/model-hz.
207 // this way all systems are updated the _same_ amount of dt.
209 int multiLoop = long(floor(dt * model_hz));
210 multiLoop = SGMisc<long>::max(0, multiLoop);
211 _dtRemainder = dt - double(multiLoop)/double(model_hz);
212 dt = double(multiLoop)/double(model_hz);
215 if (_clockFreeze->getBoolValue() || wait_for_scenery) {
221 _lastStamp = currentStamp;
222 globals->inc_sim_time_sec(simDt);
224 // These are useful, especially for Nasal scripts.
225 fgSetDouble("/sim/time/delta-realtime-sec", realDt);
226 fgSetDouble("/sim/time/delta-sec", simDt);
229 void TimeManager::update(double dt)
231 bool freeze = _clockFreeze->getBoolValue();
232 time_t now = time(NULL);
235 // clock freeze requested
236 if (_timeOverride->getLongValue() == 0) {
237 _timeOverride->setLongValue(now);
238 _adjustWarpOnUnfreeze = true;
241 // no clock freeze requested
242 if (_lastClockFreeze) {
243 if (_adjustWarpOnUnfreeze) {
244 // clock just unfroze, let's set warp as the difference
245 // between frozen time and current time so we don't get a
246 // time jump (and corresponding sky object and lighting
248 int adjust = _timeOverride->getLongValue() - now;
249 SG_LOG(SG_GENERAL, SG_INFO, "adjusting on un-freeze:" << adjust);
250 _warp->setIntValue(_warp->getIntValue() + adjust);
252 _timeOverride->setLongValue(0);
255 int warpDelta = _warpDelta->getIntValue();
256 if (warpDelta != 0) {
257 _warp->setIntValue(_warp->getIntValue() + warpDelta);
261 _lastClockFreeze = freeze;
262 double lon = _longitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
263 double lat = _latitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
264 _impl->update(lon, lat,
265 _timeOverride->getLongValue(),
266 _warp->getIntValue());
271 void TimeManager::computeFrameRate()
273 // Calculate frame rate average
274 if ((_impl->get_cur_time() != _lastFrameTime)) {
275 _frameRate->setIntValue(_frameCount);
276 _frameLatency->setDoubleValue(_frameLatencyMax*1000);
278 _frameLatencyMax = 0.0;
281 _lastFrameTime = _impl->get_cur_time();
285 void TimeManager::throttleUpdateRate()
287 double throttle_hz = fgGetDouble("/sim/frame-rate-throttle-hz", 0.0);
288 SGTimeStamp currentStamp;
290 // common case, no throttle requested
291 if (throttle_hz <= 0.0) {
295 double frame_us = 1000000.0 / throttle_hz;
296 #define FG_SLEEP_BASED_TIMING 1
297 #if defined(FG_SLEEP_BASED_TIMING)
298 // sleep based timing loop.
300 // Calling sleep, even usleep() on linux is less accurate than
301 // we like, but it does free up the cpu for other tasks during
302 // the sleep so it is desirable. Because of the way sleep()
303 // is implemented in consumer operating systems like windows
304 // and linux, you almost always sleep a little longer than the
307 // To combat the problem of sleeping too long, we calculate the
308 // desired wait time and shorten it by 2000us (2ms) to avoid
309 // [hopefully] over-sleep'ing. The 2ms value was arrived at
310 // via experimentation. We follow this up at the end with a
311 // simple busy-wait loop to get the final pause timing exactly
314 // Assuming we don't oversleep by more than 2000us, this
315 // should be a reasonable compromise between sleep based
316 // waiting, and busy waiting.
318 // sleep() will always overshoot by a bit so undersleep by
319 // 2000us in the hopes of never oversleeping.
321 if ( frame_us < 0.0 ) {
325 currentStamp.stamp();
327 double elapsed_us = (currentStamp - _lastStamp).toUSecs();
328 if ( elapsed_us < frame_us ) {
329 double requested_us = frame_us - elapsed_us;
332 Sleep ((int)(requested_us / 1000.0)) ;
334 usleep(requested_us) ;
339 // busy wait timing loop.
341 // This yields the most accurate timing. If the previous
342 // ulMilliSecondSleep() call is omitted this will peg the cpu
343 // (which is just fine if FG is the only app you care about.)
344 currentStamp.stamp();
345 SGTimeStamp next_time_stamp = _lastStamp;
346 next_time_stamp += SGTimeStamp::fromSec(1e-6*frame_us);
347 while ( currentStamp < next_time_stamp ) {
348 currentStamp.stamp();
352 // periodic time updater wrapper
353 void TimeManager::updateLocalTime()
355 SGPath zone(globals->get_fg_root());
356 zone.append("Timezone");
358 double lon = _longitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
359 double lat = _latitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
361 SG_LOG(SG_GENERAL, SG_INFO, "updateLocal(" << lon << ", " << lat << ", " << zone.str() << ")");
362 _impl->updateLocal(lon, lat, zone.str());
365 void TimeManager::initTimeOffset()
368 int offset = fgGetInt("/sim/startup/time-offset");
369 string offset_type = fgGetString("/sim/startup/time-offset-type");
370 setTimeOffset(offset_type, offset);
373 void TimeManager::setTimeOffset(const std::string& offset_type, int offset)
375 // Handle potential user specified time offsets
376 int orig_warp = _warp->getIntValue();
377 time_t cur_time = _impl->get_cur_time();
378 time_t currGMT = sgTimeGetGMT( gmtime(&cur_time) );
379 time_t systemLocalTime = sgTimeGetGMT( localtime(&cur_time) );
380 time_t aircraftLocalTime =
381 sgTimeGetGMT( fgLocaltime(&cur_time, _impl->get_zonename() ) );
383 // Okay, we now have several possible scenarios
384 double lon = _longitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
385 double lat = _latitudeDeg->getDoubleValue() * SG_DEGREES_TO_RADIANS;
388 if ( offset_type == "real" ) {
390 } else if ( offset_type == "dawn" ) {
391 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 90.0, true );
392 } else if ( offset_type == "morning" ) {
393 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 75.0, true );
394 } else if ( offset_type == "noon" ) {
395 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 0.0, true );
396 } else if ( offset_type == "afternoon" ) {
397 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 60.0, false );
398 } else if ( offset_type == "dusk" ) {
399 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 90.0, false );
400 } else if ( offset_type == "evening" ) {
401 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 100.0, false );
402 } else if ( offset_type == "midnight" ) {
403 warp = fgTimeSecondsUntilSunAngle( cur_time, lon, lat, 180.0, false );
404 } else if ( offset_type == "system-offset" ) {
407 } else if ( offset_type == "gmt-offset" ) {
408 warp = offset - (currGMT - systemLocalTime);
410 } else if ( offset_type == "latitude-offset" ) {
411 warp = offset - (aircraftLocalTime - systemLocalTime);
413 } else if ( offset_type == "system" ) {
414 warp = offset - (systemLocalTime - currGMT) - cur_time;
415 } else if ( offset_type == "gmt" ) {
416 warp = offset - cur_time;
417 } else if ( offset_type == "latitude" ) {
418 warp = offset - (aircraftLocalTime - currGMT)- cur_time;
420 SG_LOG( SG_GENERAL, SG_ALERT,
421 "TimeManager::setTimeOffset: unsupported offset: " << offset_type );
425 _warp->setIntValue( orig_warp + warp );
427 SG_LOG( SG_GENERAL, SG_INFO, "After TimeManager::setTimeOffset(): warp = "
428 << _warp->getIntValue() );