1 // FGAIBallistic - FGAIBase-derived class creates a ballistic object
3 // Written by David Culp, started November 2003.
4 // - davidculp2@comcast.net
6 // With major additions by Mathias Froehlich & Vivian Meazza 2004-2007
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26 #include <simgear/math/point3d.hxx>
27 #include <simgear/math/sg_random.h>
28 #include <simgear/scene/material/mat.hxx>
29 #include <simgear/math/sg_geodesy.hxx>
31 #include <Scenery/scenery.hxx>
33 #include "AIBallistic.hxx"
35 const double FGAIBallistic::slugs_to_kgs = 14.5939029372;
37 FGAIBallistic::FGAIBallistic() :
38 FGAIBase(otBallistic),
39 _aero_stabilised(false),
48 _report_collision(false),
49 _report_impact(false),
50 _impact_report_node(fgGetNode("/ai/models/model-impact", true)),
57 FGAIBallistic::~FGAIBallistic() {
60 void FGAIBallistic::readFromScenario(SGPropertyNode* scFileNode) {
64 FGAIBase::readFromScenario(scFileNode);
66 setAzimuth(scFileNode->getDoubleValue("azimuth", 0.0));
67 setElevation(scFileNode->getDoubleValue("elevation", 0.0));
68 setDragArea(scFileNode->getDoubleValue("eda", 0.007));
69 setLife(scFileNode->getDoubleValue("life", 900.0));
70 setBuoyancy(scFileNode->getDoubleValue("buoyancy", 0));
71 setWind_from_east(scFileNode->getDoubleValue("wind_from_east", 0));
72 setWind_from_north(scFileNode->getDoubleValue("wind_from_north", 0));
73 setWind(scFileNode->getBoolValue("wind", false));
74 setRoll(scFileNode->getDoubleValue("roll", 0.0));
75 setCd(scFileNode->getDoubleValue("cd", 0.029));
76 setMass(scFileNode->getDoubleValue("mass", 0.007));
77 setStabilisation(scFileNode->getBoolValue("aero_stabilized", false));
78 setNoRoll(scFileNode->getBoolValue("no-roll", false));
79 setRandom(scFileNode->getBoolValue("random", false));
80 setImpact(scFileNode->getBoolValue("impact", false));
81 setImpactReportNode(scFileNode->getStringValue("impact-reports"));
82 setName(scFileNode->getStringValue("name", "Bomb"));
83 setFuseRange(scFileNode->getDoubleValue("fuse-range", 0.0));
84 setSMPath(scFileNode->getStringValue("submodel-path", ""));
85 setSubID(scFileNode->getIntValue("SubID", 0));
88 bool FGAIBallistic::init(bool search_in_AI_path) {
89 FGAIBase::init(search_in_AI_path);
91 props->setStringValue("material/name", _mat_name.c_str());
92 props->setStringValue("name", _name.c_str());
93 props->setStringValue("submodels/path", _submodel.c_str());
95 // start with high value so that animations don't trigger yet
105 void FGAIBallistic::bind() {
107 props->tie("sim/time/elapsed-sec",
108 SGRawValueMethods<FGAIBallistic,double>(*this,
109 &FGAIBallistic::_getTime));
110 props->tie("material/load-resistance",
111 SGRawValuePointer<double>(&_load_resistance));
112 props->tie("material/solid",
113 SGRawValuePointer<bool>(&_solid));
114 props->tie("altitude-agl-ft",
115 SGRawValuePointer<double>(&_ht_agl_ft));
118 void FGAIBallistic::unbind() {
119 // FGAIBase::unbind();
120 props->untie("sim/time/elapsed-sec");
121 props->untie("material/load-resistance");
122 props->untie("material/solid");
123 props->untie("altitude-agl-ft");
126 void FGAIBallistic::update(double dt) {
127 FGAIBase::update(dt);
132 void FGAIBallistic::setAzimuth(double az) {
136 void FGAIBallistic::setElevation(double el) {
137 pitch = _elevation = el;
140 void FGAIBallistic::setRoll(double rl) {
144 void FGAIBallistic::setStabilisation(bool val) {
145 _aero_stabilised = val;
148 void FGAIBallistic::setNoRoll(bool nr) {
152 void FGAIBallistic::setDragArea(double a) {
156 void FGAIBallistic::setLife(double seconds) {
160 void FGAIBallistic::setBuoyancy(double fpss) {
164 void FGAIBallistic::setWind_from_east(double fps) {
165 _wind_from_east = fps;
168 void FGAIBallistic::setWind_from_north(double fps) {
169 _wind_from_north = fps;
172 void FGAIBallistic::setWind(bool val) {
176 void FGAIBallistic::setCd(double c) {
180 void FGAIBallistic::setMass(double m) {
184 void FGAIBallistic::setRandom(bool r) {
188 void FGAIBallistic::setImpact(bool i) {
192 void FGAIBallistic::setCollision(bool c) {
193 _report_collision = c;
196 void FGAIBallistic::setImpactReportNode(const string& path) {
198 _impact_report_node = fgGetNode(path.c_str(), true);
201 void FGAIBallistic::setName(const string& n) {
205 void FGAIBallistic::setSMPath(const string& s) {
209 void FGAIBallistic::setFuseRange(double f) {
213 void FGAIBallistic::setSubID(int i) {
215 //cout << "sub id " << _subID << " name " << _name << endl;
218 void FGAIBallistic::setSubmodel(const string& s) {
222 void FGAIBallistic::Run(double dt) {
224 //cout << "life timer" <<_name <<" " << _life_timer << dt << endl;
225 if (_life_timer > life)
228 //randomise Cd by +- 5%
230 _Cd = _Cd * 0.95 + (0.05 * sg_random());
232 // Adjust Cd by Mach number. The equations are based on curves
233 // for a conventional shell/bullet (no boat-tail).
237 Cdm = 0.0125 * Mach + _Cd;
238 else if (Mach < 1.2 )
239 Cdm = 0.3742 * pow(Mach, 2) - 0.252 * Mach + 0.0021 + _Cd;
241 Cdm = 0.2965 * pow(Mach, -1.1506) + _Cd;
243 //cout << " Mach , " << Mach << " , Cdm , " << Cdm << " ballistic speed kts //"<< speed << endl;
245 // drag = Cd * 0.5 * rho * speed * speed * drag_area;
246 // rho is adjusted for altitude in void FGAIBase::update,
247 // using Standard Atmosphere (sealevel temperature 15C)
248 // acceleration = drag/mass;
249 // adjust speed by drag
250 speed -= (Cdm * 0.5 * rho * speed * speed * _drag_area/_mass) * dt;
252 // don't let speed become negative
256 double speed_fps = speed * SG_KT_TO_FPS;
259 // calculate vertical and horizontal speed components
263 vs = sin( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
264 hs = cos( _elevation * SG_DEGREES_TO_RADIANS ) * speed_fps;
267 // convert horizontal speed (fps) to degrees per second
268 double speed_north_deg_sec = cos(hdg / SG_RADIANS_TO_DEGREES) * hs / ft_per_deg_lat;
269 double speed_east_deg_sec = sin(hdg / SG_RADIANS_TO_DEGREES) * hs / ft_per_deg_lon;
271 // if wind not required, set to zero
273 _wind_from_north = 0;
277 // convert wind speed (fps) to degrees per second
278 double wind_speed_from_north_deg_sec = _wind_from_north / ft_per_deg_lat;
279 double wind_speed_from_east_deg_sec = _wind_from_east / ft_per_deg_lon;
282 pos.setLatitudeDeg( pos.getLatitudeDeg()
283 + (speed_north_deg_sec - wind_speed_from_north_deg_sec) * dt );
284 pos.setLongitudeDeg( pos.getLongitudeDeg()
285 + (speed_east_deg_sec - wind_speed_from_east_deg_sec) * dt );
287 // adjust vertical speed for acceleration of gravity and buoyancy
288 vs -= (_gravity - _buoyancy) * dt;
290 // adjust altitude (feet)
291 altitude_ft += vs * dt;
292 pos.setElevationFt(altitude_ft);
294 // recalculate elevation (velocity vector) if aerostabilized
295 /*cout << _name << ": " << "aero_stabilised " << _aero_stabilised
296 << " pitch " << pitch <<" vs " << vs <<endl ;*/
298 if (_aero_stabilised) { // we simulate rotational moment of inertia by using a filter
299 const double coeff = 0.9;
300 double c = dt / (coeff + dt);
301 //cout << "c " << c << endl;
302 _elevation = atan2( vs, hs ) * SG_RADIANS_TO_DEGREES;
303 pitch = (_elevation * c) + (pitch * (1 - c));
306 // recalculate total speed
307 speed = sqrt( vs * vs + hs * hs) / SG_KT_TO_FPS;
309 //do impacts and collisions
310 if (_report_impact && !_impact_reported)
313 if (_report_collision && !_collision_reported)
316 // set destruction flag if altitude less than sea level -1000
317 if (altitude_ft < -1000.0)
322 double FGAIBallistic::_getTime() const {
323 // cout << "life timer 2" << _life_timer << endl;
327 void FGAIBallistic::handle_impact() {
329 const SGMaterial* material;
331 // try terrain intersection
332 if (!globals->get_scenery()->get_elevation_m(pos.getLatitudeDeg(), pos.getLongitudeDeg(),
333 10000.0, elevation_m, &material))
337 const vector<string> names = material->get_names();
340 _mat_name = names[0].c_str();
342 _solid = material->get_solid();
343 _load_resistance = material->get_load_resistance();
344 props->setStringValue("material/name", _mat_name.c_str());
345 //cout << "material " << _mat_name << " solid " << _solid << " load " << _load_resistance << endl;
348 _ht_agl_ft = pos.getElevationFt() - elevation_m * SG_METER_TO_FEET;
350 if (_ht_agl_ft <= 0) {
351 SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: terrain impact");
352 report_impact(elevation_m);
353 _impact_reported = true;
355 // kill the AIObject if there is no subsubmodel
361 void FGAIBallistic::handle_collision()
363 const FGAIBase *object = manager->calcCollision(pos.getElevationFt(),
364 pos.getLatitudeDeg(),pos.getLongitudeDeg(), _fuse_range);
367 SG_LOG(SG_GENERAL, SG_DEBUG, "AIBallistic: object hit");
368 report_impact(pos.getElevationM(), object);
369 _collision_reported = true;
373 void FGAIBallistic::report_impact(double elevation, const FGAIBase *object)
375 _impact_lat = pos.getLatitudeDeg();
376 _impact_lon = pos.getLongitudeDeg();
377 _impact_elev = elevation;
378 _impact_speed = speed * SG_KT_TO_MPS;
380 _impact_pitch = pitch;
383 SGPropertyNode *n = props->getNode("impact", true);
385 n->setStringValue("type", object->getTypeString());
387 n->setStringValue("type", "terrain");
389 n->setDoubleValue("longitude-deg", _impact_lon);
390 n->setDoubleValue("latitude-deg", _impact_lat);
391 n->setDoubleValue("elevation-m", _impact_elev);
392 n->setDoubleValue("heading-deg", _impact_hdg);
393 n->setDoubleValue("pitch-deg", _impact_pitch);
394 n->setDoubleValue("roll-deg", _impact_roll);
395 n->setDoubleValue("speed-mps", _impact_speed);
397 _impact_report_node->setStringValue(props->getPath());