1 // FGAIAircraft - FGAIBase-derived class creates an AI airplane
3 // Written by David Culp, started October 2003.
5 // Copyright (C) 2003 David P. Culp - davidculp2@comcast.net
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., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <simgear/math/point3d.hxx>
26 #include <Main/fg_props.hxx>
27 #include <Main/globals.hxx>
28 #include <Scenery/scenery.hxx>
34 #include "AIAircraft.hxx"
37 // accel, decel, climb_rate, descent_rate, takeoff_speed, climb_speed,
38 // cruise_speed, descent_speed, land_speed
40 const FGAIAircraft::PERF_STRUCT FGAIAircraft::settings[] = {
42 {2.0, 2.0, 450.0, 1000.0, 70.0, 80.0, 100.0, 80.0, 60.0},
44 {4.0, 2.0, 3000.0, 1500.0, 110.0, 180.0, 250.0, 200.0, 100.0},
46 {5.0, 2.0, 3000.0, 1500.0, 140.0, 300.0, 430.0, 300.0, 130.0},
48 {7.0, 3.0, 4000.0, 2000.0, 150.0, 350.0, 500.0, 350.0, 150.0}
52 FGAIAircraft *FGAIAircraft::_self = NULL;
54 FGAIAircraft::FGAIAircraft(FGAIManager* mgr) {
55 _self = this; // This needs to be the first entry.
57 _type_str = "aircraft";
63 // set heading and altitude locks
69 FGAIAircraft::~FGAIAircraft() {
75 bool FGAIAircraft::init() {
76 return FGAIBase::init();
79 void FGAIAircraft::bind() {
82 props->tie("controls/gear/gear-down",
83 SGRawValueFunctions<bool>(FGAIAircraft::_getGearDown));
86 props->getNode("controls/lighting/landing-lights", true)
87 ->alias("controls/gear/gear-down");
91 void FGAIAircraft::unbind() {
94 props->untie("controls/gear/gear-down");
95 // props->getNode("controls/lighting/landing-lights")->unalias();
99 void FGAIAircraft::update(double dt) {
103 FGAIBase::update(dt);
106 void FGAIAircraft::SetPerformance(const PERF_STRUCT *ps) {
112 void FGAIAircraft::Run(double dt) {
114 FGAIAircraft::dt = dt;
116 if (fp) ProcessFlightPlan(dt);
118 double turn_radius_ft;
119 double turn_circum_ft;
120 double speed_north_deg_sec;
121 double speed_east_deg_sec;
122 double ft_per_deg_lon;
123 double ft_per_deg_lat;
124 double dist_covered_ft;
127 // get size of a degree at this latitude
128 ft_per_deg_lat = 366468.96 - 3717.12 * cos(pos.lat()/SG_RADIANS_TO_DEGREES);
129 ft_per_deg_lon = 365228.16 * cos(pos.lat() / SG_RADIANS_TO_DEGREES);
132 double speed_diff = tgt_speed - speed;
133 if (fabs(speed_diff) > 0.2) {
134 if (speed_diff > 0.0) speed += performance->accel * dt;
135 if (speed_diff < 0.0) speed -= performance->decel * dt;
138 // convert speed to degrees per second
139 speed_north_deg_sec = cos( hdg / SG_RADIANS_TO_DEGREES )
140 * speed * 1.686 / ft_per_deg_lat;
141 speed_east_deg_sec = sin( hdg / SG_RADIANS_TO_DEGREES )
142 * speed * 1.686 / ft_per_deg_lon;
145 pos.setlat( pos.lat() + speed_north_deg_sec * dt);
146 pos.setlon( pos.lon() + speed_east_deg_sec * dt);
148 // adjust heading based on current bank angle
150 turn_radius_ft = 0.088362 * speed * speed
151 / tan( fabs(roll) / SG_RADIANS_TO_DEGREES );
152 turn_circum_ft = SGD_2PI * turn_radius_ft;
153 dist_covered_ft = speed * 1.686 * dt;
154 alpha = dist_covered_ft / turn_circum_ft * 360.0;
155 hdg += alpha * sign( roll );
156 if ( hdg > 360.0 ) hdg -= 360.0;
157 if ( hdg < 0.0) hdg += 360.0;
160 // adjust target bank angle if heading lock engaged
162 double bank_sense = 0.0;
163 double diff = fabs(hdg - tgt_heading);
164 if (diff > 180) diff = fabs(diff - 360);
165 double sum = hdg + diff;
166 if (sum > 360.0) sum -= 360.0;
167 if (fabs(sum - tgt_heading) < 1.0) {
168 bank_sense = 1.0; // right turn
170 bank_sense = -1.0; // left turn
173 tgt_roll = diff * bank_sense;
175 tgt_roll = 30.0 * bank_sense;
179 // adjust bank angle, use 9 degrees per second
180 double bank_diff = tgt_roll - roll;
181 if (fabs(bank_diff) > 0.2) {
182 if (bank_diff > 0.0) roll += 9.0 * dt;
183 if (bank_diff < 0.0) roll -= 9.0 * dt;
186 // adjust altitude (meters) based on current vertical speed (fpm)
187 altitude += vs / 60.0 * dt;
188 pos.setelev(altitude * SG_FEET_TO_METER);
189 double altitude_ft = altitude;
191 // find target vertical speed if altitude lock engaged
192 if (alt_lock && use_perf_vs) {
193 if (altitude_ft < tgt_altitude) {
194 tgt_vs = tgt_altitude - altitude_ft;
195 if (tgt_vs > performance->climb_rate)
196 tgt_vs = performance->climb_rate;
198 tgt_vs = tgt_altitude - altitude_ft;
199 if (tgt_vs < (-performance->descent_rate))
200 tgt_vs = -performance->descent_rate;
204 if (alt_lock && !use_perf_vs) {
205 double max_vs = 2*(tgt_altitude - altitude);
206 if ((fabs(tgt_altitude - altitude) < 1500.0) &&
207 (fabs(max_vs) < fabs(tgt_vs))) tgt_vs = max_vs;
210 // adjust vertical speed
211 double vs_diff = tgt_vs - vs;
212 if (fabs(vs_diff) > 10.0) {
215 if (vs > tgt_vs) vs = tgt_vs;
218 if (vs < tgt_vs) vs = tgt_vs;
222 // match pitch angle to vertical speed
225 //###########################//
226 // do calculations for radar //
227 //###########################//
229 // copy values from the AIManager
230 double user_latitude = manager->get_user_latitude();
231 double user_longitude = manager->get_user_longitude();
232 double user_altitude = manager->get_user_altitude();
233 double user_heading = manager->get_user_heading();
234 double user_pitch = manager->get_user_pitch();
235 double user_yaw = manager->get_user_yaw();
236 double user_speed = manager->get_user_speed();
238 // calculate range to target in feet and nautical miles
239 double lat_range = fabs(pos.lat() - user_latitude) * ft_per_deg_lat;
240 double lon_range = fabs(pos.lon() - user_longitude) * ft_per_deg_lon;
241 double range_ft = sqrt( lat_range*lat_range + lon_range*lon_range );
242 range = range_ft / 6076.11549;
244 // calculate bearing to target
245 if (pos.lat() >= user_latitude) {
246 bearing = atan2(lat_range, lon_range) * SG_RADIANS_TO_DEGREES;
247 if (pos.lon() >= user_longitude) {
248 bearing = 90.0 - bearing;
250 bearing = 270.0 + bearing;
253 bearing = atan2(lon_range, lat_range) * SG_RADIANS_TO_DEGREES;
254 if (pos.lon() >= user_longitude) {
255 bearing = 180.0 - bearing;
257 bearing = 180.0 + bearing;
261 // calculate look left/right to target, without yaw correction
262 horiz_offset = bearing - user_heading;
263 if (horiz_offset > 180.0) horiz_offset -= 360.0;
264 if (horiz_offset < -180.0) horiz_offset += 360.0;
266 // calculate elevation to target
267 elevation = atan2( altitude_ft - user_altitude, range_ft )
268 * SG_RADIANS_TO_DEGREES;
270 // calculate look up/down to target
271 vert_offset = elevation + user_pitch;
273 /* this calculation needs to be fixed, but it isn't important anyway
274 // calculate range rate
275 double recip_bearing = bearing + 180.0;
276 if (recip_bearing > 360.0) recip_bearing -= 360.0;
277 double my_horiz_offset = recip_bearing - hdg;
278 if (my_horiz_offset > 180.0) my_horiz_offset -= 360.0;
279 if (my_horiz_offset < -180.0) my_horiz_offset += 360.0;
280 rdot = (-user_speed * cos( horiz_offset * SG_DEGREES_TO_RADIANS ))
281 + (-speed * 1.686 * cos( my_horiz_offset * SG_DEGREES_TO_RADIANS ));
284 // now correct look left/right for yaw
285 horiz_offset += user_yaw;
287 // calculate values for radar display
288 y_shift = range * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
289 x_shift = range * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
290 rotation = hdg - user_heading;
291 if (rotation < 0.0) rotation += 360.0;
296 void FGAIAircraft::AccelTo(double speed) {
301 void FGAIAircraft::PitchTo(double angle) {
307 void FGAIAircraft::RollTo(double angle) {
313 void FGAIAircraft::YawTo(double angle) {
318 void FGAIAircraft::ClimbTo(double altitude) {
319 tgt_altitude = altitude;
324 void FGAIAircraft::TurnTo(double heading) {
325 tgt_heading = heading;
330 double FGAIAircraft::sign(double x) {
331 if ( x < 0.0 ) { return -1.0; }
335 void FGAIAircraft::SetFlightPlan(FGAIFlightPlan *f) {
339 void FGAIAircraft::ProcessFlightPlan( double dt ) {
340 FGAIFlightPlan::waypoint* prev = 0; // the one behind you
341 FGAIFlightPlan::waypoint* curr = 0; // the one ahead
342 FGAIFlightPlan::waypoint* next = 0; // the next plus 1
343 prev = fp->getPreviousWaypoint();
344 curr = fp->getCurrentWaypoint();
345 next = fp->getNextWaypoint();
348 if (!prev) { //beginning of flightplan, do this initialization once
349 fp->IncrementWaypoint();
350 prev = fp->getPreviousWaypoint(); //first waypoint
351 curr = fp->getCurrentWaypoint(); //second waypoint
352 next = fp->getNextWaypoint(); //third waypoint (might not exist!)
353 setLatitude(prev->latitude);
354 setLongitude(prev->longitude);
355 setSpeed(prev->speed);
356 setAltitude(prev->altitude);
357 setHeading(fp->getBearing(prev->latitude, prev->longitude, curr));
358 if (next) fp->setLeadDistance(speed, hdg, curr, next);
360 if (curr->crossat > -1000.0) { //start descent/climb now
362 tgt_vs = (curr->crossat - prev->altitude)/
363 (fp->getDistanceToGo(pos.lat(), pos.lon(), curr)/
364 6076.0/prev->speed*60.0);
365 tgt_altitude = curr->crossat;
368 tgt_altitude = prev->altitude;
370 alt_lock = hdg_lock = true;
371 //cout << "First waypoint: " << prev->name << endl;
372 //cout << " Target speed: " << tgt_speed << endl;
373 //cout << " Target altitude: " << tgt_altitude << endl;
374 //cout << " Target heading: " << tgt_heading << endl << endl;
376 } // end of initialization
378 // let's only process the flight plan every 100 ms.
379 if (dt_count < 0.1) {
384 // check to see if we've reached the lead point for our next turn
385 double dist_to_go = fp->getDistanceToGo(pos.lat(), pos.lon(), curr);
386 double lead_dist = fp->getLeadDistance();
387 if (lead_dist < (2*speed)) lead_dist = 2*speed; //don't skip over the waypoint
388 //cout << "dist_to_go: " << dist_to_go << ", lead_dist: " << lead_dist << endl;
390 if ( dist_to_go < lead_dist ) {
391 if (curr->finished) { //end of the flight plan, so terminate
395 // we've reached the lead-point for the waypoint ahead
396 if (next) tgt_heading = fp->getBearing(curr, next);
397 fp->IncrementWaypoint();
398 prev = fp->getPreviousWaypoint();
399 curr = fp->getCurrentWaypoint();
400 next = fp->getNextWaypoint();
401 if (next) fp->setLeadDistance(speed, tgt_heading, curr, next);
402 if (curr->crossat > -1000.0) {
404 tgt_vs = (curr->crossat - altitude)/
405 (fp->getDistanceToGo(pos.lat(), pos.lon(), curr)/6076.0/speed*60.0);
406 tgt_altitude = curr->crossat;
409 tgt_altitude = prev->altitude;
411 tgt_speed = prev->speed;
412 hdg_lock = alt_lock = true;
413 //cout << "Crossing waypoint: " << prev->name << endl;
414 //cout << " Target speed: " << tgt_speed << endl;
415 //cout << " Target altitude: " << tgt_altitude << endl;
416 //cout << " Target heading: " << tgt_heading << endl << endl;
418 double calc_bearing = fp->getBearing(pos.lat(), pos.lon(), curr);
419 double hdg_error = calc_bearing - tgt_heading;
420 if (fabs(hdg_error) > 1.0) {
421 TurnTo( calc_bearing );