Change a hot-spot in the AI code, to use cartesian instead of geodetic math.

diff --git a/src/AIModel/AIAircraft.cxx b/src/AIModel/AIAircraft.cxx
index a87a94fe61492d9856ce5ba1b85f371f75621853..2722886c6053750a54e5007a6c3e4dc440582cb2 100644 (file)
--- a/src/AIModel/AIAircraft.cxx
+++ b/src/AIModel/AIAircraft.cxx
@@ -838,11 +838,12 @@ bool FGAIAircraft::leadPointReached(FGAIWaypoint* curr) {
 }
 
 
-bool FGAIAircraft::aiTrafficVisible() {
-  SGGeod userPos(SGGeod::fromDeg(fgGetDouble("/position/longitude-deg"), 
-    fgGetDouble("/position/latitude-deg")));
-  
-  return (SGGeodesy::distanceNm(userPos, pos) <= TRAFFICTOAIDISTTODIE);
+bool FGAIAircraft::aiTrafficVisible()
+{
+    SGVec3d cartPos = SGVec3d::fromGeod(pos);
+    const double d2 = (TRAFFICTOAIDISTTODIE * SG_NM_TO_METER) *
+        (TRAFFICTOAIDISTTODIE * SG_NM_TO_METER);
+    return (distSqr(cartPos, globals->get_aircraft_positon_cart()) < d2);
 }
 
 

diff --git a/src/Main/globals.cxx b/src/Main/globals.cxx
index 4d6d7bf57ec776e3f7a02ef91582371ebf33a214..c4bb125a7151bd4add70f34c26453e08eac7f002 100644 (file)
--- a/src/Main/globals.cxx
+++ b/src/Main/globals.cxx
@@ -380,6 +380,11 @@ FGGlobals::get_aircraft_position() const
     throw sg_exception("Can't get aircraft position", "FGGlobals::get_aircraft_position()" );
 }
 
+const SGVec3d&
+FGGlobals::get_aircraft_positon_cart() const
+{
+    return SGVec3d::fromGeod(get_aircraft_position());
+}
 
 
 // Save the current state as the initial state.

diff --git a/src/Main/globals.hxx b/src/Main/globals.hxx
index 54b777a71842c4769a18cbff448b15791d8814a4..365ce39887a96a71f413433adbb1bbb21e92f3ce 100644 (file)
--- a/src/Main/globals.hxx
+++ b/src/Main/globals.hxx
@@ -267,6 +267,8 @@ public:
 
     const SGGeod & get_aircraft_position() const;
 
+    const SGVec3d& get_aircraft_positon_cart() const;
+    
     inline FGModelMgr *get_model_mgr () { return model_mgr; }
 
     inline void set_model_mgr (FGModelMgr * mgr)