1 // FGAIBase - abstract base class for AI objects
2 // Written by David Culp, started Nov 2003, based on
3 // David Luff's FGAIEntity class.
4 // - davidculp2@comcast.net
6 // This program is free software; you can redistribute it and/or
7 // modify it under the terms of the GNU General Public License as
8 // published by the Free Software Foundation; either version 2 of the
9 // License, or (at your option) any later version.
11 // This program is distributed in the hope that it will be useful, but
12 // WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 // General Public License for more details.
16 // You should have received a copy of the GNU General Public License
17 // along with this program; if not, write to the Free Software
18 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <simgear/compiler.h>
32 #include <simgear/math/point3d.hxx>
33 #include <simgear/misc/sg_path.hxx>
34 #include <simgear/scene/model/location.hxx>
35 #include <simgear/scene/model/model.hxx>
36 #include <simgear/debug/logstream.hxx>
37 #include <simgear/props/props.hxx>
39 #include <Main/globals.hxx>
40 #include <Scenery/scenery.hxx>
44 #include "AIManager.hxx"
47 const double FGAIBase::e = 2.71828183;
48 const double FGAIBase::lbs_to_slugs = 0.031080950172; //conversion factor
58 tgt_roll = roll = tgt_pitch = tgt_yaw = tgt_vs = vs = pitch = 0.0;
59 bearing = elevation = range = rdot = 0.0;
60 x_shift = y_shift = rotation = 0.0;
71 FGAIBase::~FGAIBase() {
72 globals->get_scenery()->get_scene_graph()->removeKid(aip.getSceneGraph());
74 SGPropertyNode *root = globals->get_props()->getNode("ai/models", true);
75 root->removeChild(_type_str.c_str(), index);
80 void FGAIBase::update(double dt) {
81 ft_per_deg_lat = 366468.96 - 3717.12 * cos(pos.lat()*SGD_DEGREES_TO_RADIANS);
82 ft_per_deg_lon = 365228.16 * cos(pos.lat()*SGD_DEGREES_TO_RADIANS);
84 // Calculate rho at altitude, using standard atmosphere
85 // For the temperature T and the pressure p,
87 if (altitude < 36152) { // curve fits for the troposphere
88 T = 59 - 0.00356 * altitude;
89 p = 2116 * pow( ((T + 459.7) / 518.6) , 5.256);
91 } else if ( 36152 < altitude && altitude < 82345 ) { // lower stratosphere
93 p = 473.1 * pow( e , 1.73 - (0.000048 * altitude) );
95 } else { // upper stratosphere
96 T = -205.05 + (0.00164 * altitude);
97 p = 51.97 * pow( ((T + 459.7) / 389.98) , -11.388);
100 rho = p / (1718 * (T + 459.7));
102 // calculate the speed of sound at altitude
103 // a = sqrt ( g * R * (T + 459.7))
105 // a = speed of sound [ft/s]
106 // g = specific heat ratio, which is usually equal to 1.4
107 // R = specific gas constant, which equals 1716 ft-lb/slug/°R
109 a = sqrt ( 1.4 * 1716 * (T + 459.7));
111 // calculate Mach number
115 // cout << "Speed(ft/s) "<< speed <<" Altitude(ft) "<< altitude << " Mach " << Mach;
118 void FGAIBase::Transform() {
120 aip.setPosition(pos.lon(), pos.lat(), pos.elev() * SG_METER_TO_FEET);
122 aip.setOrientation(0.0, pitch, hdg);
124 aip.setOrientation(roll, pitch, hdg);
126 aip.update( globals->get_scenery()->get_center() );
131 bool FGAIBase::init() {
133 SGPropertyNode *root = globals->get_props()->getNode("ai/models", true);
135 index = manager->getNum(_otype) - 1;
136 props = root->getNode(_type_str.c_str(), index, true);
138 if (model_path != "") {
139 model = sgLoad3DModel( globals->get_fg_root(),
142 globals->get_sim_time_sec() );
146 aip.setVisible(true);
148 globals->get_scenery()->get_scene_graph()->addKid(aip.getSceneGraph());
150 if (model_path != "") {
151 SG_LOG(SG_INPUT, SG_WARN, "AIBase: Could not load model.");
160 bool FGAIBase::isa( object_type otype ) {
161 if ( otype == _otype ) { return true; }
162 else { return false; }
166 void FGAIBase::bind() {
167 props->tie("id", SGRawValueMethods<FGAIBase,int>(*this,
169 props->tie("velocities/true-airspeed-kt", SGRawValuePointer<double>(&speed));
170 props->tie("velocities/vertical-speed-fps",
171 SGRawValueMethods<FGAIBase,double>(*this,
172 &FGAIBase::_getVS_fps,
173 &FGAIBase::_setVS_fps));
175 props->tie("position/altitude-ft",
176 SGRawValueMethods<FGAIBase,double>(*this,
177 &FGAIBase::_getAltitude,
178 &FGAIBase::_setAltitude));
179 props->tie("position/latitude-deg",
180 SGRawValueMethods<FGAIBase,double>(*this,
181 &FGAIBase::_getLatitude,
182 &FGAIBase::_setLatitude));
183 props->tie("position/longitude-deg",
184 SGRawValueMethods<FGAIBase,double>(*this,
185 &FGAIBase::_getLongitude,
186 &FGAIBase::_setLongitude));
188 props->tie("orientation/pitch-deg", SGRawValuePointer<double>(&pitch));
189 props->tie("orientation/roll-deg", SGRawValuePointer<double>(&roll));
190 props->tie("orientation/true-heading-deg", SGRawValuePointer<double>(&hdg));
192 props->tie("radar/in-range", SGRawValuePointer<bool>(&in_range));
193 props->tie("radar/bearing-deg", SGRawValuePointer<double>(&bearing));
194 props->tie("radar/elevation-deg", SGRawValuePointer<double>(&elevation));
195 props->tie("radar/range-nm", SGRawValuePointer<double>(&range));
196 props->tie("radar/h-offset", SGRawValuePointer<double>(&horiz_offset));
197 props->tie("radar/v-offset", SGRawValuePointer<double>(&vert_offset));
198 props->tie("radar/x-shift", SGRawValuePointer<double>(&x_shift));
199 props->tie("radar/y-shift", SGRawValuePointer<double>(&y_shift));
200 props->tie("radar/rotation", SGRawValuePointer<double>(&rotation));
202 props->tie("controls/lighting/nav-lights",
203 SGRawValueFunctions<bool>(_isNight));
204 props->setBoolValue("controls/lighting/beacon", true);
205 props->setBoolValue("controls/lighting/strobe", true);
206 props->setBoolValue("controls/glide-path", true);
209 void FGAIBase::unbind() {
211 props->untie("velocities/true-airspeed-kt");
212 props->untie("velocities/vertical-speed-fps");
214 props->untie("position/altitude-ft");
215 props->untie("position/latitude-deg");
216 props->untie("position/longitude-deg");
218 props->untie("orientation/pitch-deg");
219 props->untie("orientation/roll-deg");
220 props->untie("orientation/true-heading-deg");
222 props->untie("radar/in-range");
223 props->untie("radar/bearing-deg");
224 props->untie("radar/elevation-deg");
225 props->untie("radar/range-nm");
226 props->untie("radar/h-offset");
227 props->untie("radar/v-offset");
228 props->untie("radar/x-shift");
229 props->untie("radar/y-shift");
230 props->untie("radar/rotation");
232 props->untie("controls/lighting/nav-lights");
235 double FGAIBase::UpdateRadar(FGAIManager* manager)
237 double radar_range_ft2 = fgGetDouble("/instrumentation/radar/range");
238 radar_range_ft2 *= SG_NM_TO_METER * SG_METER_TO_FEET * 1.1; // + 10%
239 radar_range_ft2 *= radar_range_ft2;
241 double user_latitude = manager->get_user_latitude();
242 double user_longitude = manager->get_user_longitude();
243 double lat_range = fabs(pos.lat() - user_latitude) * ft_per_deg_lat;
244 double lon_range = fabs(pos.lon() - user_longitude) * ft_per_deg_lon;
245 double range_ft2 = lat_range*lat_range + lon_range*lon_range;
248 // Test whether the target is within radar range.
250 in_range = (range_ft2 && (range_ft2 <= radar_range_ft2));
253 props->setBoolValue("radar/in-range", true);
255 // copy values from the AIManager
256 double user_altitude = manager->get_user_altitude();
257 double user_heading = manager->get_user_heading();
258 double user_pitch = manager->get_user_pitch();
259 double user_yaw = manager->get_user_yaw();
260 double user_speed = manager->get_user_speed();
262 // calculate range to target in feet and nautical miles
263 double range_ft = sqrt( range_ft2 );
264 range = range_ft / 6076.11549;
266 // calculate bearing to target
267 if (pos.lat() >= user_latitude) {
268 bearing = atan2(lat_range, lon_range) * SG_RADIANS_TO_DEGREES;
269 if (pos.lon() >= user_longitude) {
270 bearing = 90.0 - bearing;
272 bearing = 270.0 + bearing;
275 bearing = atan2(lon_range, lat_range) * SG_RADIANS_TO_DEGREES;
276 if (pos.lon() >= user_longitude) {
277 bearing = 180.0 - bearing;
279 bearing = 180.0 + bearing;
283 // calculate look left/right to target, without yaw correction
284 horiz_offset = bearing - user_heading;
285 if (horiz_offset > 180.0) horiz_offset -= 360.0;
286 if (horiz_offset < -180.0) horiz_offset += 360.0;
288 // calculate elevation to target
289 elevation = atan2( altitude * SG_METER_TO_FEET - user_altitude, range_ft )
290 * SG_RADIANS_TO_DEGREES;
292 // calculate look up/down to target
293 vert_offset = elevation + user_pitch;
295 /* this calculation needs to be fixed, but it isn't important anyway
296 // calculate range rate
297 double recip_bearing = bearing + 180.0;
298 if (recip_bearing > 360.0) recip_bearing -= 360.0;
299 double my_horiz_offset = recip_bearing - hdg;
300 if (my_horiz_offset > 180.0) my_horiz_offset -= 360.0;
301 if (my_horiz_offset < -180.0) my_horiz_offset += 360.0;
302 rdot = (-user_speed * cos( horiz_offset * SG_DEGREES_TO_RADIANS ))
303 +(-speed * 1.686 * cos( my_horiz_offset * SG_DEGREES_TO_RADIANS ));
306 // now correct look left/right for yaw
307 horiz_offset += user_yaw;
309 // calculate values for radar display
310 y_shift = range * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
311 x_shift = range * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
312 rotation = hdg - user_heading;
313 if (rotation < 0.0) rotation += 360.0;
322 * getters and Setters
324 void FGAIBase::_setLongitude( double longitude ) {
325 pos.setlon(longitude);
327 void FGAIBase::_setLatitude ( double latitude ) {
328 pos.setlat(latitude);
331 double FGAIBase::_getLongitude() const {
334 double FGAIBase::_getLatitude () const {
337 double FGAIBase::_getRdot() const {
340 double FGAIBase::_getVS_fps() const {
343 void FGAIBase::_setVS_fps( double _vs ) {
347 double FGAIBase::_getAltitude() const {
350 void FGAIBase::_setAltitude( double _alt ) {
354 bool FGAIBase::_isNight() {
355 return (fgGetFloat("/sim/time/sun-angle-rad") > 1.57);
358 int FGAIBase::_getID() const {