Fix NaN in FGAILocalTraffic::FlyTrafficPattern

diff --git a/src/ATCDCL/AILocalTraffic.cxx b/src/ATCDCL/AILocalTraffic.cxx
index 6c1b77d8f5da776381435328fe7c13074fdfcacc..f96c38992bdd4db68b2e6b48f10725e0ba311ecd 100644 (file)
--- a/src/ATCDCL/AILocalTraffic.cxx
+++ b/src/ATCDCL/AILocalTraffic.cxx
@@ -1146,24 +1146,8 @@ void FGAILocalTraffic::FlyTrafficPattern(double dt) {
                double axx = gxx - wxx; // Plane in-air velocity x component
                double ayy = gyy - wyy; // Plane in-air velocity y component
                // Now we want the angle between gxx and axx (which is the crab)
-               double maga = sqrt(axx*axx + ayy*ayy);
-               double magg = sqrt(gxx*gxx + gyy*gyy);
-               crab = acos((axx*gxx + ayy*gyy) / (maga * magg));
-               // At this point this works except we're getting the modulus of the angle
+               crab = atan2(ayy - gyy, axx - gxx) * DCL_RADIANS_TO_DEGREES;
                //cout << "crab = " << crab << '\n';
-               
-               // Make sure both headings are in the 0->360 circle in order to get sane differences
-               dclBoundHeading(wind_from);
-               dclBoundHeading(track);
-               if(track > wind_from) {
-                       if((track - wind_from) <= 180) {
-                               crab *= -1.0;
-                       }
-               } else {
-                       if((wind_from - track) >= 180) {
-                               crab *= -1.0;
-                       }
-               }
        } else {        // on the ground - crab dosen't apply
                crab = 0.0;
        }
@@ -1171,6 +1155,7 @@ void FGAILocalTraffic::FlyTrafficPattern(double dt) {
        //cout << "X " << orthopos.x() << "  Y " << orthopos.y() << "  SLOPE " << slope << "  elev " << _pos.elev() * SG_METER_TO_FEET << '\n';
        
        _hdg = track + crab;
+       dclBoundHeading(_hdg);
        dist = vel * 0.514444 * dt;
        _pos = dclUpdatePosition(_pos, track, slope, dist);
 }