]> git.mxchange.org Git - flightgear.git/blobdiff - src/AIModel/AIManager.cxx
Add a small bit of nan/fpe protection. It's possible that this routine
[flightgear.git] / src / AIModel / AIManager.cxx
index 027d59b50a68843bbd406b366f1b7ed4da7905b3..4190981124242bea13257c082babf70a59c18b60 100644 (file)
@@ -2,7 +2,7 @@
 // - a global management type for AI objects
 //
 // Written by David Culp, started October 2003.
-// - davidculp2@comcast.net
+// - davidculp2@comcast.net 
 //
 // This program is free software; you can redistribute it and/or
 // modify it under the terms of the GNU General Public License as
 // along with this program; if not, write to the Free Software
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
+#include <cstring>
+
+#include <simgear/math/sg_geodesy.hxx>
+#include <simgear/props/props_io.hxx>
+#include <simgear/structure/exception.hxx>
+
 #include <Main/globals.hxx>
 
 #include <Airports/simple.hxx>
 #include "AICarrier.hxx"
 #include "AIStatic.hxx"
 #include "AIMultiplayer.hxx"
+#include "AITanker.hxx"
+#include "AIWingman.hxx"
+#include "AIGroundVehicle.hxx"
+#include "AIEscort.hxx"
 
 FGAIManager::FGAIManager() {
-  _dt = 0.0;
-  mNumAiModels = 0;
-  for (unsigned i = 0; i < FGAIBase::MAX_OBJECTS; ++i)
-    mNumAiTypeModels[i] = 0;
-}
+    _dt = 0.0;
+    mNumAiModels = 0;
 
-FGAIManager::~FGAIManager() {
-  ai_list_iterator ai_list_itr = ai_list.begin();
-  while(ai_list_itr != ai_list.end()) {
-      (*ai_list_itr)->unbind();
-      ++ai_list_itr;
-  }
+    for (unsigned i = 0; i < FGAIBase::MAX_OBJECTS; ++i)
+        mNumAiTypeModels[i] = 0;
 }
 
+FGAIManager::~FGAIManager() {
+    ai_list_iterator ai_list_itr = ai_list.begin();
 
-void FGAIManager::init() {
-  root = fgGetNode("sim/ai", true);
-
-  enabled = root->getNode("enabled", true)->getBoolValue();
-  if (!enabled)
-      return;
-
-  wind_from_down_node = fgGetNode("/environment/wind-from-down-fps", true);
-  wind_from_east_node  = fgGetNode("/environment/wind-from-east-fps",true);
-  wind_from_north_node = fgGetNode("/environment/wind-from-north-fps",true);
+    while(ai_list_itr != ai_list.end()) {
+        (*ai_list_itr)->unbind();
+        ++ai_list_itr;
+    }
+}
 
-  user_latitude_node  = fgGetNode("/position/latitude-deg", true);
-  user_longitude_node = fgGetNode("/position/longitude-deg", true);
-  user_altitude_node  = fgGetNode("/position/altitude-ft", true);
-  user_heading_node   = fgGetNode("/orientation/heading-deg", true);
-  user_pitch_node     = fgGetNode("/orientation/pitch-deg", true);
-  user_yaw_node       = fgGetNode("/orientation/side-slip-deg", true);
-  user_speed_node     = fgGetNode("/velocities/uBody-fps", true);
+void
+FGAIManager::init() {
+    root = fgGetNode("sim/ai", true);
+
+    enabled = root->getNode("enabled", true)->getBoolValue();
+
+    if (!enabled)
+        return;
+
+    thermal_lift_node = fgGetNode("/environment/thermal-lift-fps", true);
+    wind_from_east_node  = fgGetNode("/environment/wind-from-east-fps",true);
+    wind_from_north_node = fgGetNode("/environment/wind-from-north-fps",true);
+
+    user_latitude_node  = fgGetNode("/position/latitude-deg", true);
+    user_longitude_node = fgGetNode("/position/longitude-deg", true);
+    user_altitude_node  = fgGetNode("/position/altitude-ft", true);
+    user_altitude_agl_node  = fgGetNode("/position/altitude-agl-ft", true);
+    user_heading_node   = fgGetNode("/orientation/heading-deg", true);
+    user_pitch_node     = fgGetNode("/orientation/pitch-deg", true);
+    user_yaw_node       = fgGetNode("/orientation/side-slip-deg", true);
+    user_roll_node      = fgGetNode("/orientation/roll-deg", true);
+    user_speed_node     = fgGetNode("/velocities/uBody-fps", true);
+}
 
+void
+FGAIManager::postinit() {
+    // postinit, so that it can access the Nasal subsystem
+    map<string, bool> scenarios;
+    for (int i = 0 ; i < root->nChildren() ; i++) {
+        SGPropertyNode *n = root->getChild(i);
+        if (strcmp(n->getName(), "scenario"))
+            continue;
+
+        string name = n->getStringValue();
+        if (name.empty())
+            continue;
+
+        if (scenarios.find(name) != scenarios.end()) {
+            SG_LOG(SG_GENERAL, SG_DEBUG, "won't load scenario '" << name << "' twice");
+            continue;
+        }
 
-  /// Move that into the constructor
-  for(int i = 0 ; i < root->nChildren() ; i++) {
-    SGPropertyNode *aiEntry = root->getChild( i );
-    if( !strcmp( aiEntry->getName(), "scenario" ) ) {
-      scenario_filename = aiEntry->getStringValue();
-      if (!scenario_filename.empty())
-        processScenario( scenario_filename );
+        SG_LOG(SG_GENERAL, SG_ALERT, "loading scenario '" << name << '\'');
+        processScenario(name);
+        scenarios[name] = true;
     }
-  }
 }
 
+void
+FGAIManager::reinit() {
+    update(0.0);
 
-void FGAIManager::reinit() {
-   update(0.0);
-   ai_list_iterator ai_list_itr = ai_list.begin();
+    ai_list_iterator ai_list_itr = ai_list.begin();
 
-   while(ai_list_itr != ai_list.end()) {
-      (*ai_list_itr)->reinit();
-      ++ai_list_itr;
-   }
+    while(ai_list_itr != ai_list.end()) {
+        (*ai_list_itr)->reinit();
+        ++ai_list_itr;
+    }
 }
 
-
-void FGAIManager::bind() {
-   root = globals->get_props()->getNode("ai/models", true);
-   root->tie("count", SGRawValueMethods<FGAIManager, int>(*this,
-             &FGAIManager::getNumAiObjects));
+void
+FGAIManager::bind() {
+    root = globals->get_props()->getNode("ai/models", true);
+    root->tie("count", SGRawValueMethods<FGAIManager, int>(*this,
+        &FGAIManager::getNumAiObjects));
 }
 
-
-void FGAIManager::unbind() {
+void
+FGAIManager::unbind() {
     root->untie("count");
 }
 
-
-void FGAIManager::update(double dt) {
-  // initialize these for finding nearest thermals
-  range_nearest = 10000.0;
-  strength = 0.0;
-  if (!enabled)
-    return;
-
-  FGTrafficManager *tmgr = (FGTrafficManager*) globals->get_subsystem("Traffic Manager");
-  _dt = dt;
-
-  ai_list_iterator ai_list_itr = ai_list.begin();
-  while(ai_list_itr != ai_list.end()) {
-    if ((*ai_list_itr)->getDie()) {      
-      tmgr->release((*ai_list_itr)->getID());
-      --mNumAiModels;
-      --(mNumAiTypeModels[(*ai_list_itr)->getType()]);
-      (*ai_list_itr)->unbind();
-      ai_list_itr = ai_list.erase(ai_list_itr);
-    } else {
-      fetchUserState();
-      if ((*ai_list_itr)->isa(FGAIBase::otThermal)) {
-        FGAIBase *base = *ai_list_itr;
-        processThermal((FGAIThermal*)base); 
-      } else { 
-        (*ai_list_itr)->update(_dt);
-      }
-      ++ai_list_itr;
+void
+FGAIManager::update(double dt) {
+    // initialize these for finding nearest thermals
+    range_nearest = 10000.0;
+    strength = 0.0;
+
+    if (!enabled)
+        return;
+
+    FGTrafficManager *tmgr = (FGTrafficManager*) globals->get_subsystem("Traffic Manager");
+    _dt = dt;
+
+    ai_list_iterator ai_list_itr = ai_list.begin();
+
+    while(ai_list_itr != ai_list.end()) {
+
+        if ((*ai_list_itr)->getDie()) {
+            tmgr->release((*ai_list_itr)->getID());
+            --mNumAiModels;
+            --(mNumAiTypeModels[(*ai_list_itr)->getType()]);
+            FGAIBase *base = (*ai_list_itr).get();
+            SGPropertyNode *props = base->_getProps();
+
+            props->setBoolValue("valid", false);
+            base->unbind();
+
+            // for backward compatibility reset properties, so that aircraft,
+            // which don't know the <valid> property, keep working
+            // TODO: remove after a while
+            props->setIntValue("id", -1);
+            props->setBoolValue("radar/in-range", false);
+            props->setIntValue("refuel/tanker", false);
+
+            ai_list_itr = ai_list.erase(ai_list_itr);
+        } else {
+            fetchUserState();
+            if ((*ai_list_itr)->isa(FGAIBase::otThermal)) {
+                FGAIBase *base = (*ai_list_itr).get();
+                processThermal((FGAIThermal*)base);
+            } else {
+                (*ai_list_itr)->update(_dt);
+            }
+            ++ai_list_itr;
+        }
     }
-  }
-  wind_from_down_node->setDoubleValue( strength ); // for thermals
+
+    thermal_lift_node->setDoubleValue( strength );  // for thermals
 }
 
 void
-FGAIManager::attach(SGSharedPtr<FGAIBase> model)
+FGAIManager::attach(FGAIBase *model)
 {
-  unsigned idx = mNumAiTypeModels[model->getType()];
-  const char* typeString = model->getTypeString();
-  SGPropertyNode* root = globals->get_props()->getNode("ai/models", true);
-  SGPropertyNode* p;
-  int i;
-  for (i=0;i<10000;i++) //find free index in the property tree, if we have
-      //more than 10000 mp-aircrafts in the property tree we should optimize the mp-server
-  {
-    p = root->getNode(typeString, i, false);
-    if (!p) break;
-    if (p->getIntValue("id",-1)==model->getID())
-    {
-        p->setStringValue("callsign","***invalid node***"); //debug only, should never set!
-                                              
+    //unsigned idx = mNumAiTypeModels[model->getType()];
+    const char* typeString = model->getTypeString();
+    SGPropertyNode* root = globals->get_props()->getNode("ai/models", true);
+    SGPropertyNode* p;
+    int i;
+
+    // find free index in the property tree, if we have
+    // more than 10000 mp-aircrafts in the property tree we should optimize the mp-server
+    for (i = 0; i < 10000; i++) {
+        p = root->getNode(typeString, i, false);
+
+        if (!p || !p->getBoolValue("valid", false))
+            break;
+
+        if (p->getIntValue("id",-1)==model->getID()) {
+            p->setStringValue("callsign","***invalid node***"); //debug only, should never set!
+        }
     }
-  }
-  p = root->getNode(typeString, i, true);
-  model->setManager(this, p);
-  ai_list.push_back(model);
-  ++mNumAiModels;
-  ++(mNumAiTypeModels[model->getType()]);
-  model->init(model->getType()==FGAIBase::otAircraft
-      || model->getType()==FGAIBase::otMultiplayer
-      || model->getType()==FGAIBase::otStatic);
-  model->bind();
+
+    p = root->getNode(typeString, i, true);
+    model->setManager(this, p);
+    ai_list.push_back(model);
+    ++mNumAiModels;
+    ++(mNumAiTypeModels[model->getType()]);
+    model->init(model->getType()==FGAIBase::otAircraft
+        || model->getType()==FGAIBase::otMultiplayer
+        || model->getType()==FGAIBase::otStatic);
+    model->bind();
+    p->setBoolValue("valid", true);
 }
 
+void
+FGAIManager::destroyObject( int ID ) {
+    ai_list_iterator ai_list_itr = ai_list.begin();
+
+    while(ai_list_itr != ai_list.end()) {
+
+        if ((*ai_list_itr)->getID() == ID) {
+            --mNumAiModels;
+            --(mNumAiTypeModels[(*ai_list_itr)->getType()]);
+            (*ai_list_itr)->unbind();
+            ai_list_itr = ai_list.erase(ai_list_itr);
+        } else
+            ++ai_list_itr;
+    }
 
-void FGAIManager::destroyObject( int ID ) {
-  ai_list_iterator ai_list_itr = ai_list.begin();
-  while(ai_list_itr != ai_list.end()) {
-    if ((*ai_list_itr)->getID() == ID) {
-      --mNumAiModels;
-      --(mNumAiTypeModels[(*ai_list_itr)->getType()]);
-      (*ai_list_itr)->unbind();
-      ai_list_itr = ai_list.erase(ai_list_itr);
-    } else
-      ++ai_list_itr;
-  }
 }
 
 int
 FGAIManager::getNumAiObjects(void) const
 {
-  return mNumAiModels;
+    return mNumAiModels;
 }
 
-void FGAIManager::fetchUserState( void ) {
-     user_latitude  = user_latitude_node->getDoubleValue();
-     user_longitude = user_longitude_node->getDoubleValue();
-     user_altitude  = user_altitude_node->getDoubleValue();
-     user_heading   = user_heading_node->getDoubleValue();
-     user_pitch     = user_pitch_node->getDoubleValue();
-     user_yaw       = user_yaw_node->getDoubleValue();
-     user_speed     = user_speed_node->getDoubleValue() * 0.592484;
-     wind_from_east = wind_from_east_node->getDoubleValue();
-     wind_from_north = wind_from_north_node->getDoubleValue();
-}
+void
+FGAIManager::fetchUserState( void ) {
+
+    user_latitude  = user_latitude_node->getDoubleValue();
+    user_longitude = user_longitude_node->getDoubleValue();
+    user_altitude  = user_altitude_node->getDoubleValue();
+    user_heading   = user_heading_node->getDoubleValue();
+    user_pitch     = user_pitch_node->getDoubleValue();
+    user_yaw       = user_yaw_node->getDoubleValue();
+    user_speed     = user_speed_node->getDoubleValue() * 0.592484;
+    user_roll      = user_roll_node->getDoubleValue();
+    wind_from_east = wind_from_east_node->getDoubleValue();
+    wind_from_north   = wind_from_north_node->getDoubleValue();
+    user_altitude_agl = user_altitude_agl_node->getDoubleValue();
 
+}
 
 // only keep the results from the nearest thermal
-void FGAIManager::processThermal( FGAIThermal* thermal ) {
-  thermal->update(_dt);
-  if ( thermal->_getRange() < range_nearest ) {
-     range_nearest = thermal->_getRange();
-     strength = thermal->getStrength();
-  }
+void
+FGAIManager::processThermal( FGAIThermal* thermal ) {
+    thermal->update(_dt);
+
+    if ( thermal->_getRange() < range_nearest ) {
+        range_nearest = thermal->_getRange();
+        strength = thermal->getStrength();
+    }
+
 }
 
 
-void FGAIManager::processScenario( const string &filename ) {
-
-  SGPropertyNode_ptr scenarioTop = loadScenarioFile(filename);
-  if (!scenarioTop)
-    return;
-  SGPropertyNode* scenarios = scenarioTop->getChild("scenario");
-  if (!scenarios)
-    return;
-
-  for (int i = 0; i < scenarios->nChildren(); i++) { 
-    SGPropertyNode* scEntry = scenarios->getChild(i);
-    std::string type = scEntry->getStringValue("type", "aircraft");
-
-    if (type == "aircraft") {
-      FGAIAircraft* aircraft = new FGAIAircraft;
-      aircraft->readFromScenario(scEntry);
-      attach(aircraft);
-
-    } else if (type == "ship") {
-      FGAIShip* ship = new FGAIShip;
-      ship->readFromScenario(scEntry);
-      attach(ship);
-      
-    } else if (type == "carrier") {
-      FGAICarrier* carrier = new FGAICarrier;
-      carrier->readFromScenario(scEntry);
-      attach(carrier);
-      
-    } else if (type == "thunderstorm") {
-      FGAIStorm* storm = new FGAIStorm;
-      storm->readFromScenario(scEntry);
-      attach(storm);
-      
-    } else if (type == "thermal") {
-      FGAIThermal* thermal = new FGAIThermal;
-      thermal->readFromScenario(scEntry);
-      attach(thermal);
-      
-    } else if (type == "ballistic") {
-      FGAIBallistic* ballistic = new FGAIBallistic;
-      ballistic->readFromScenario(scEntry);
-      attach(ballistic);
-      
-    } else if (type == "static") {
-      FGAIStatic* aistatic = new FGAIStatic;
-      aistatic->readFromScenario(scEntry);
-      attach(aistatic);
-      
+
+void
+FGAIManager::processScenario( const string &filename ) {
+
+    SGPropertyNode_ptr scenarioTop = loadScenarioFile(filename);
+
+    if (!scenarioTop)
+        return;
+
+    SGPropertyNode* scenarios = scenarioTop->getChild("scenario");
+
+    if (!scenarios)
+        return;
+
+    for (int i = 0; i < scenarios->nChildren(); i++) {
+        SGPropertyNode* scEntry = scenarios->getChild(i);
+
+        if (strcmp(scEntry->getName(), "entry"))
+            continue;
+        std::string type = scEntry->getStringValue("type", "aircraft");
+
+        if (type == "tanker") { // refueling scenarios
+            FGAITanker* tanker = new FGAITanker;
+            tanker->readFromScenario(scEntry);
+            attach(tanker);
+
+        } else if (type == "wingman") {
+            FGAIWingman* wingman = new FGAIWingman;
+            wingman->readFromScenario(scEntry);
+            attach(wingman);
+
+        } else if (type == "aircraft") {
+            FGAIAircraft* aircraft = new FGAIAircraft;
+            aircraft->readFromScenario(scEntry);
+            attach(aircraft);
+
+        } else if (type == "ship") {
+            FGAIShip* ship = new FGAIShip;
+            ship->readFromScenario(scEntry);
+            attach(ship);
+
+        } else if (type == "carrier") {
+            FGAICarrier* carrier = new FGAICarrier;
+            carrier->readFromScenario(scEntry);
+            attach(carrier);
+
+        } else if (type == "groundvehicle") {
+            FGAIGroundVehicle* groundvehicle = new FGAIGroundVehicle;
+            groundvehicle->readFromScenario(scEntry);
+            attach(groundvehicle);
+
+        } else if (type == "escort") {
+            FGAIEscort* escort = new FGAIEscort;
+            escort->readFromScenario(scEntry);
+            attach(escort);
+
+        } else if (type == "thunderstorm") {
+            FGAIStorm* storm = new FGAIStorm;
+            storm->readFromScenario(scEntry);
+            attach(storm);
+
+        } else if (type == "thermal") {
+            FGAIThermal* thermal = new FGAIThermal;
+            thermal->readFromScenario(scEntry);
+            attach(thermal);
+
+        } else if (type == "ballistic") {
+            FGAIBallistic* ballistic = new FGAIBallistic;
+            ballistic->readFromScenario(scEntry);
+            attach(ballistic);
+
+        } else if (type == "static") {
+            FGAIStatic* aistatic = new FGAIStatic;
+            aistatic->readFromScenario(scEntry);
+            attach(aistatic);
+        }
+
     }
-  }
+
 }
 
 SGPropertyNode_ptr
 FGAIManager::loadScenarioFile(const std::string& filename)
 {
-  SGPath path(globals->get_fg_root());
-  path.append("AI/" + filename + ".xml");
-  try {
-    SGPropertyNode_ptr root = new SGPropertyNode;
-    readProperties(path.str(), root);
-    return root;
-  } catch (const sg_exception &e) {
-    SG_LOG(SG_GENERAL, SG_ALERT, "Incorrect path specified for AI "
-           "scenario: \"" << path.str() << "\"");
-    return 0;
-  }
+    SGPath path(globals->get_fg_root());
+    path.append("AI/" + filename + ".xml");
+    try {
+        SGPropertyNode_ptr root = new SGPropertyNode;
+        readProperties(path.str(), root);
+        return root;
+    } catch (const sg_exception &) {
+        SG_LOG(SG_GENERAL, SG_DEBUG, "Incorrect path specified for AI "
+            "scenario: \"" << path.str() << "\"");
+        return 0;
+    }
 }
 
-bool FGAIManager::getStartPosition(const string& id, const string& pid,
-                                   SGGeod& geodPos, double& hdng, SGVec3d& uvw)
+bool
+FGAIManager::getStartPosition(const string& id, const string& pid,
+                              SGGeod& geodPos, double& hdng, SGVec3d& uvw)
 {
-  bool found = false;
-  SGPropertyNode* root = fgGetNode("sim/ai", true);
-  if (!root->getNode("enabled", true)->getBoolValue())
-      return found;
-
-  for(int i = 0 ; (!found) && i < root->nChildren() ; i++) {
-    SGPropertyNode *aiEntry = root->getChild( i );
-    if( !strcmp( aiEntry->getName(), "scenario" ) ) {
-      string filename = aiEntry->getStringValue();
-      SGPropertyNode_ptr scenarioTop = loadScenarioFile(filename);
-      if (scenarioTop) {
-        SGPropertyNode* scenarios = scenarioTop->getChild("scenario");
-        if (scenarios) {
-          for (int i = 0; i < scenarios->nChildren(); i++) { 
-            SGPropertyNode* scEntry = scenarios->getChild(i);
-            std::string type = scEntry->getStringValue("type");
-            std::string pnumber = scEntry->getStringValue("pennant-number");
-            std::string name = scEntry->getStringValue("name");
-            if (type == "carrier" && (pnumber == id || name == id)) {
-              SGSharedPtr<FGAICarrier> carrier = new FGAICarrier;
-              carrier->readFromScenario(scEntry);
-              
-              if (carrier->getParkPosition(pid, geodPos, hdng, uvw)) {
-                found = true;
-                break;
-              }
+    bool found = false;
+    SGPropertyNode* root = fgGetNode("sim/ai", true);
+    if (!root->getNode("enabled", true)->getBoolValue())
+        return found;
+
+    for (int i = 0 ; (!found) && i < root->nChildren() ; i++) {
+        SGPropertyNode *aiEntry = root->getChild( i );
+        if ( !strcmp( aiEntry->getName(), "scenario" ) ) {
+            string filename = aiEntry->getStringValue();
+            SGPropertyNode_ptr scenarioTop = loadScenarioFile(filename);
+            if (scenarioTop) {
+                SGPropertyNode* scenarios = scenarioTop->getChild("scenario");
+                if (scenarios) {
+                    for (int i = 0; i < scenarios->nChildren(); i++) {
+                        SGPropertyNode* scEntry = scenarios->getChild(i);
+                        std::string type = scEntry->getStringValue("type");
+                        std::string pnumber = scEntry->getStringValue("pennant-number");
+                        std::string name = scEntry->getStringValue("name");
+                        if (type == "carrier" && (pnumber == id || name == id)) {
+                            SGSharedPtr<FGAICarrier> carrier = new FGAICarrier;
+                            carrier->readFromScenario(scEntry);
+
+                            if (carrier->getParkPosition(pid, geodPos, hdng, uvw)) {
+                                found = true;
+                                break;
+                            }
+                        }
+                    }
+                }
             }
-          }
         }
-      }
     }
-  }
-  return found;
+    return found;
+}
+
+const FGAIBase *
+FGAIManager::calcCollision(double alt, double lat, double lon, double fuse_range)
+{
+    // we specify tgt extent (ft) according to the AIObject type
+    double tgt_ht[]     = {0,  50, 100, 250, 0, 100, 0, 0,  50,  50, 20, 100,  50};
+    double tgt_length[] = {0, 100, 200, 750, 0,  50, 0, 0, 200, 100, 40, 200, 100};
+    ai_list_iterator ai_list_itr = ai_list.begin();
+    ai_list_iterator end = ai_list.end();
+
+    while (ai_list_itr != end) {
+        double tgt_alt = (*ai_list_itr)->_getAltitude();
+        int type       = (*ai_list_itr)->getType();
+        tgt_ht[type] += fuse_range;
+
+        if (fabs(tgt_alt - alt) > tgt_ht[type] || type == FGAIBase::otBallistic
+            || type == FGAIBase::otStorm || type == FGAIBase::otThermal ) {
+                //SG_LOG(SG_GENERAL, SG_DEBUG, "AIManager: skipping "
+                //    << fabs(tgt_alt - alt)
+                //    << " "
+                //    << type
+                //    );
+                ++ai_list_itr;
+                continue;
+        }
+
+        double tgt_lat = (*ai_list_itr)->_getLatitude();
+        double tgt_lon = (*ai_list_itr)->_getLongitude();
+        int id         = (*ai_list_itr)->getID();
+
+        double range = calcRange(lat, lon, tgt_lat, tgt_lon);
+
+        //SG_LOG(SG_GENERAL, SG_DEBUG, "AIManager:  AI list size "
+        //    << ai_list.size()
+        //    << " type " << type
+        //    << " ID " << id
+        //    << " range " << range
+        //    //<< " bearing " << bearing
+        //    << " alt " << tgt_alt
+        //    );
+
+        tgt_length[type] += fuse_range;
+
+        if (range < tgt_length[type]){
+            SG_LOG(SG_GENERAL, SG_DEBUG, "AIManager: HIT! "
+                << " type " << type
+                << " ID " << id
+                << " range " << range
+                << " alt " << tgt_alt
+                );
+            return (*ai_list_itr).get();
+        }
+        ++ai_list_itr;
+    }
+    return 0;
+}
+
+double
+FGAIManager::calcRange(double lat, double lon, double lat2, double lon2) const
+{
+    double course, az2, distance;
+
+    //calculate the bearing and range of the second pos from the first
+    geo_inverse_wgs_84(lat, lon, lat2, lon2, &course, &az2, &distance);
+    distance *= SG_METER_TO_FEET;
+    return distance;
 }
 
 //end AIManager.cxx