Merge branch 'Next'

Include/Constants.h

@@ -29,7 +29,7 @@
 //
 // MARK: Version Information (CHANGE VERSION HERE)
 //
-constexpr float VERSION_NR = 1.23f;
+constexpr float VERSION_NR = 1.24f;
 constexpr bool VERSION_BETA = false;
 extern float verXPlaneOrg;          // version on X-Plane.org
 extern int verDateXPlaneOrg;        // and its date

Include/CoordCalc.h

@@ -75,6 +75,43 @@ vectorTy CoordVectorBetween (const positionTy& from, const positionTy& to );
 // destination point given a starting point and a vetor
 positionTy CoordPlusVector (const positionTy& pos, const vectorTy& vec);
 
+// returns terrain altitude at given position
+// returns NaN in case of failure
+double YProbe_at_m (const positionTy& posAt, XPLMProbeRef& probeRef);
+
+//
+// MARK: Estimated Functions on coordinates
+//
+
+/// @details Length of a degree latitude
+/// @see https://en.wikipedia.org/wiki/Geographic_coordinate_system#Length_of_a_degree
+constexpr double LAT_DEG_IN_MTR = 111132.95;
+/// @details Length of a degree longitude
+/// @see https://en.wikipedia.org/wiki/Geographic_coordinate_system#Length_of_a_degree
+inline double LonDegInMtr (double lat) { return LAT_DEG_IN_MTR * std::cos(deg2rad(lat)); }
+
+/// @brief An _estimated_ **square** of the distance between 2 points given by lat/lon
+/// @details Makes use simple formulas to convert lat/lon differences into meters
+///          So this is not exact but quick and good enough for many purposes.
+///          On short distances of less than 10m, difference to CoordDistance() is a few millimeters.
+/// @return Square of distance (estimated) in meter
+double DistLatLonSqr (double lat1, double lon1,
+                      double lat2, double lon2);
+
+/// @brief An _estimated_ distance between 2 points given by lat/lon
+/// @details Makes use simple formulas to convert lat/lon differences into meters
+///          So this is not exact but quick and good enough for many purposes.
+///          On short distances of less than 10m, difference to CoordDistance() is a few millimeters.
+/// @return Distance (estimated) in meter
+inline double DistLatLon (double lat1, double lon1,
+                          double lat2, double lon2)
+{ return std::sqrt(DistLatLonSqr(lat1,lon1,lat2,lon2)); }
+
+
+//
+// MARK: Functions on 2D points, typically in meters
+//
+
 /// @brief Simple square of distance just by Pythagoras
 inline double DistPythSqr (double x1, double y1,
                            double x2, double y2)
@@ -126,10 +163,6 @@ void DistResultToBaseLoc (double ln_x1, double ln_y1,
                           const distToLineTy& res,
                           double &x, double &y);
 
-// returns terrain altitude at given position
-// returns NaN in case of failure
-double YProbe_at_m (const positionTy& posAt, XPLMProbeRef& probeRef);
-
 //
 //MARK: Data Structures
 //

Src/CoordCalc.cpp

@@ -115,6 +115,15 @@ positionTy CoordPlusVector (const positionTy& p, const vectorTy& vec)
     return ret.rad2deg();
 }
 
+//An estimated square of the distance between 2 points given by lat/lon
+double DistLatLonSqr (double lat1, double lon1,
+                      double lat2, double lon2)
+{
+    const double dx = (lon2-lon1) * LonDegInMtr((lat1+lat2)/2);
+    const double dz = (lat2-lat1) * LAT_DEG_IN_MTR;
+    return sqr(dx) + sqr(dz);
+}
+
 // Square of distance between a location and a line defined by two points.
 void DistPointToLineSqr (double pt_x, double pt_y,
                          double ln_x1, double ln_y1,

Src/DataRefs.cpp

@@ -754,22 +754,29 @@ bool DataRefs::RegisterCommands()
     return bRet;
 }
 
+
 // Did the reference point to the local coordinate system change since last call to this function?
 /// @note Will always return `true` on first call, intentionally.
 bool DataRefs::DidLocalRefPointChange ()
 {
     const float nowLatRef = XPLMGetDataf(adrXP[DR_LAT_REF]);
     const float nowLonRef = XPLMGetDataf(adrXP[DR_LON_REF]);
 
-    // return value:
-    const bool ret = (std::isnan(lstLonRef) ||          // never asked before?
-                      (dequal(lstLatRef, nowLatRef) && dequal(lstLonRef, nowLonRef)));
-
-    // Update our known value of lat/lon reference
-    lstLatRef = nowLatRef;
-    lstLonRef = nowLonRef;
+    // Is this a change compared to what we know?
+    if (std::isnan(lstLonRef) ||          // never asked before?
+        !dequal(lstLatRef, nowLatRef) ||  // changed compared to last call?
+        !dequal(lstLonRef, nowLonRef))
+    {
+        // Update our known value of lat/lon reference
+        lstLatRef = nowLatRef;
+        lstLonRef = nowLonRef;
+
+        // ref point changed
+        return true;
+    }
 
-    return ret;
+    // no change
+    return false;
 }
 
 // return user's plane pos

Src/LTAircraft.cpp

@@ -74,10 +74,6 @@ bool NextCycle (int newCycle)
     else
         XPMPDisableAircraftLabels();
 
-    // Check if the reference point of the local coordinate system had changed
-    if (dataRefs.DidLocalRefPointChange())
-
-
     // time should move forward (positive difference) and not too much either
     // If time moved to far between two calls then we better start over
     // (but no problem if no a/c yet displayed anyway)