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) {
57 _type_str = "aircraft";
60 // set heading and altitude locks
66 FGAIAircraft::~FGAIAircraft() {
71 bool FGAIAircraft::init() {
72 return FGAIBase::init();
75 void FGAIAircraft::bind() {
78 props->tie("controls/gear/gear-down",
79 SGRawValueFunctions<bool>(FGAIAircraft::_getGearDown));
82 props->getNode("controls/lighting/landing-lights", true)
83 ->alias("controls/gear/gear-down");
87 void FGAIAircraft::unbind() {
90 props->untie("controls/gear/gear-down");
91 // props->getNode("controls/lighting/landing-lights")->unalias();
95 void FGAIAircraft::update(double dt) {
102 void FGAIAircraft::SetPerformance(const PERF_STRUCT *ps) {
108 void FGAIAircraft::Run(double dt) {
110 FGAIAircraft::dt = dt;
112 double turn_radius_ft;
113 double turn_circum_ft;
114 double speed_north_deg_sec;
115 double speed_east_deg_sec;
116 double ft_per_deg_lon;
117 double ft_per_deg_lat;
118 double dist_covered_ft;
121 // get size of a degree at this latitude
122 ft_per_deg_lat = 366468.96 - 3717.12 * cos(pos.lat()/SG_RADIANS_TO_DEGREES);
123 ft_per_deg_lon = 365228.16 * cos(pos.lat() / SG_RADIANS_TO_DEGREES);
126 double speed_diff = tgt_speed - speed;
127 if (fabs(speed_diff) > 0.2) {
128 if (speed_diff > 0.0) speed += performance->accel * dt;
129 if (speed_diff < 0.0) speed -= performance->decel * dt;
132 // convert speed to degrees per second
133 speed_north_deg_sec = cos( hdg / SG_RADIANS_TO_DEGREES )
134 * speed * 1.686 / ft_per_deg_lat;
135 speed_east_deg_sec = sin( hdg / SG_RADIANS_TO_DEGREES )
136 * speed * 1.686 / ft_per_deg_lon;
139 pos.setlat( pos.lat() + speed_north_deg_sec * dt);
140 pos.setlon( pos.lon() + speed_east_deg_sec * dt);
142 // adjust heading based on current bank angle
144 turn_radius_ft = 0.088362 * speed * speed
145 / tan( fabs(roll) / SG_RADIANS_TO_DEGREES );
146 turn_circum_ft = SGD_2PI * turn_radius_ft;
147 dist_covered_ft = speed * 1.686 * dt;
148 alpha = dist_covered_ft / turn_circum_ft * 360.0;
149 hdg += alpha * sign( roll );
150 if ( hdg > 360.0 ) hdg -= 360.0;
151 if ( hdg < 0.0) hdg += 360.0;
154 // adjust target bank angle if heading lock engaged
156 double bank_sense = 0.0;
157 double diff = fabs(hdg - tgt_heading);
158 if (diff > 180) diff = fabs(diff - 360);
159 double sum = hdg + diff;
160 if (sum > 360.0) sum -= 360.0;
161 if (fabs(sum - tgt_heading) < 1.0) {
166 if (diff < 30) tgt_roll = diff * bank_sense;
170 double bank_diff = tgt_roll - roll;
171 if (fabs(bank_diff) > 0.2) {
172 if (bank_diff > 0.0) roll += 5.0 * dt;
173 if (bank_diff < 0.0) roll -= 5.0 * dt;
176 // adjust altitude (meters) based on current vertical speed (fpm)
177 altitude += vs * 0.0166667 * dt * SG_FEET_TO_METER;
178 double altitude_ft = altitude * SG_METER_TO_FEET;
180 // find target vertical speed if altitude lock engaged
182 if (altitude_ft < tgt_altitude) {
183 tgt_vs = tgt_altitude - altitude_ft;
184 if (tgt_vs > performance->climb_rate)
185 tgt_vs = performance->climb_rate;
187 tgt_vs = tgt_altitude - altitude_ft;
188 if (tgt_vs < (-performance->descent_rate))
189 tgt_vs = -performance->descent_rate;
193 // adjust vertical speed
194 double vs_diff = tgt_vs - vs;
195 if (fabs(vs_diff) > 1.0) {
198 if (vs > tgt_vs) vs = tgt_vs;
201 if (vs < tgt_vs) vs = tgt_vs;
205 // match pitch angle to vertical speed
208 //###########################//
209 // do calculations for radar //
210 //###########################//
212 // copy values from the AIManager
213 double user_latitude = manager->get_user_latitude();
214 double user_longitude = manager->get_user_longitude();
215 double user_altitude = manager->get_user_altitude();
216 double user_heading = manager->get_user_heading();
217 double user_pitch = manager->get_user_pitch();
218 double user_yaw = manager->get_user_yaw();
219 double user_speed = manager->get_user_speed();
221 // calculate range to target in feet and nautical miles
222 double lat_range = fabs(pos.lat() - user_latitude) * ft_per_deg_lat;
223 double lon_range = fabs(pos.lon() - user_longitude) * ft_per_deg_lon;
224 double range_ft = sqrt( lat_range*lat_range + lon_range*lon_range );
225 range = range_ft / 6076.11549;
227 // calculate bearing to target
228 if (pos.lat() >= user_latitude) {
229 bearing = atan2(lat_range, lon_range) * SG_RADIANS_TO_DEGREES;
230 if (pos.lon() >= user_longitude) {
231 bearing = 90.0 - bearing;
233 bearing = 270.0 + bearing;
236 bearing = atan2(lon_range, lat_range) * SG_RADIANS_TO_DEGREES;
237 if (pos.lon() >= user_longitude) {
238 bearing = 180.0 - bearing;
240 bearing = 180.0 + bearing;
244 // calculate look left/right to target, without yaw correction
245 horiz_offset = bearing - user_heading;
246 if (horiz_offset > 180.0) horiz_offset -= 360.0;
247 if (horiz_offset < -180.0) horiz_offset += 360.0;
249 // calculate elevation to target
250 elevation = atan2( altitude_ft - user_altitude, range_ft )
251 * SG_RADIANS_TO_DEGREES;
253 // calculate look up/down to target
254 vert_offset = elevation + user_pitch;
256 /* this calculation needs to be fixed
257 // calculate range rate
258 double recip_bearing = bearing + 180.0;
259 if (recip_bearing > 360.0) recip_bearing -= 360.0;
260 double my_horiz_offset = recip_bearing - hdg;
261 if (my_horiz_offset > 180.0) my_horiz_offset -= 360.0;
262 if (my_horiz_offset < -180.0) my_horiz_offset += 360.0;
263 rdot = (-user_speed * cos( horiz_offset * SG_DEGREES_TO_RADIANS ))
264 + (-speed * 1.686 * cos( my_horiz_offset * SG_DEGREES_TO_RADIANS ));
267 // now correct look left/right for yaw
268 horiz_offset += user_yaw;
270 // calculate values for radar display
271 y_shift = range * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
272 x_shift = range * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
273 rotation = hdg - user_heading;
274 if (rotation < 0.0) rotation += 360.0;
279 void FGAIAircraft::AccelTo(double speed) {
284 void FGAIAircraft::PitchTo(double angle) {
290 void FGAIAircraft::RollTo(double angle) {
296 void FGAIAircraft::YawTo(double angle) {
301 void FGAIAircraft::ClimbTo(double altitude) {
302 tgt_altitude = altitude;
307 void FGAIAircraft::TurnTo(double heading) {
308 tgt_heading = heading;
313 double FGAIAircraft::sign(double x) {
315 if ( x < 0.0 ) { return -1.0; }