Tony's patches to allow you to position yourself at an offset from the

default location (i.e. end of the runway.)  This allows you to start
up on final and things like that.

diff --git a/src/Main/fg_init.cxx b/src/Main/fg_init.cxx
index 0c506726ffdb49e812378c8c4a30e6d03bf56aa9..d7a384760461cc2b9b754f8b93efddc3ae36dc73 100644 (file)
--- a/src/Main/fg_init.cxx
+++ b/src/Main/fg_init.cxx
@@ -330,9 +330,24 @@ bool fgSetPosFromAirportIDandHdg( const string& id, double tgt_hdg ) {
            "runway =  " << found_r.lon << ", " << found_r.lat
            << " length = " << found_r.length * FEET_TO_METER * 0.5 
            << " heading = " << azimuth );
+    
     geo_direct_wgs_84 ( 0, found_r.lat, found_r.lon, 
                        azimuth, found_r.length * FEET_TO_METER * 0.5 - 5.0,
                        &lat2, &lon2, &az2 );
+
+    if ( fabs( fgGetDouble("/sim/startup/offset-distance") ) > FG_EPSILON ) {
+       double olat, olon;
+       double odist = fgGetDouble("/sim/startup/offset-distance");
+       odist *= NM_TO_METER;
+       double oaz = azimuth;
+       if ( fabs(fgGetDouble("/sim/startup/offset-azimuth")) > FG_EPSILON ) {
+           oaz = fgGetDouble("/sim/startup/offset-azimuth") + 180;
+       }
+       while ( oaz >= 360.0 ) { oaz -= 360.0; }
+       geo_direct_wgs_84 ( 0, lat2, lon2, oaz, odist, &olat, &olon, &az2 );
+       lat2=olat;
+       lon2=olon;
+    }
     fgSetDouble("/position/longitude",  lon2 );
     fgSetDouble("/position/latitude",  lat2 );
     fgSetDouble("/orientation/heading", heading );

diff --git a/src/Main/options.cxx b/src/Main/options.cxx
index 8503dc40e43efd43e5ec0f131c282e5a3f19133c..69cbb6d6dfafafa0532bd6b2d98f44d2a0e1ff51 100644 (file)
--- a/src/Main/options.cxx
+++ b/src/Main/options.cxx
@@ -565,6 +565,10 @@ parse_option (const string& arg)
     } else if ( arg.find( "--airport-id=") != string::npos ) {
                                // NB: changed property name!!!
        fgSetString("/sim/startup/airport-id", arg.substr(13));
+    } else if ( arg.find( "--offset-distance=") != string::npos ) {
+       fgSetDouble("/sim/startup/offset-distance", atof(arg.substr(18)));
+    } else if ( arg.find( "--offset-azimuth=") != string::npos ) {
+       fgSetDouble("/sim/startup/offset-azimuth", atof(arg.substr(17))); 
     } else if ( arg.find( "--lon=" ) != string::npos ) {
        fgSetDouble("/position/longitude",
                              parse_degree(arg.substr(6)));
@@ -1060,6 +1064,10 @@ fgUsage ()
     cout << "Initial Position and Orientation:" << endl;
     cout << "\t--airport-id=ABCD:  specify starting postion by airport id" 
         << endl;
+    cout << "\t--offset-distance:  specify distance to threshhold"
+         << " (NM)" << endl; 
+    cout << "\t--offset-azimuth:  specify heading to threshhold (deg) " 
+         << endl;    
     cout << "\t--lon=degrees:  starting longitude in degrees (west = -)" 
         << endl;
     cout << "\t--lat=degrees:  starting latitude in degrees (south = -)"