Well I'm not sure exactly what the problem is. To say the least getting into some of this code isn't very easy.
Here's a patch that forces a single update after the FDM initializes. Actually I think what this does is just delay the lighting update until the second frame, since as far as I can tell the FDM isn't updated on the first pass through MainLoop. It does appear that the FDM update is critical to getting a good result from fgUpdateSkyAndLightingParams(). If anyone is interested below the patch is a log for two successive calls to the lighting update one each of during processing of frames 1 and 2. Note that there is a huge jump in the Sun position between the first and second frame. Best, Jim Index: main.cxx =================================================================== RCS file: /var/cvs/FlightGear-0.9/FlightGear/src/Main/main.cxx,v retrieving revision 1.129 diff -u -r1.129 main.cxx --- main.cxx 17 Sep 2003 10:02:36 -0000 1.129 +++ main.cxx 18 Sep 2003 01:23:50 -0000 @@ -928,6 +928,11 @@ if ( !inited ) { inited = true; + + // following run once after fdm is inited... + fgUpdateSkyAndLightingParams(); + // above run once after fdm inits + } if ( ! replay_master->getBoolValue() ) { @@ -1392,7 +1397,6 @@ fgReshape( fgGetInt("/sim/startup/xsize"), fgGetInt("/sim/startup/ysize") ); - fgUpdateSkyAndLightingParams(); } if ( idle_state == 1000 ) { Loading tile /usr/src/games/fgfs/Scenery-0.9.2/w010n00/w001n00/2938503 Updating Sun position Gst = 17.5722 t->cur_time = 1025564412 Sun Geodetic lat = 0.0366661 Geocentric lat = 0.0364209 sun angle relative to current location = 0.824245 Updating Moon position t->cur_time = 1025564412 Moon Geodetic lat = 0.433565 Geocentric lat = 0.43101 moon angle relative to current location = 0.996144 Updating light parameters. Sun angle = 47.2258 ambient = 0.2 diffuse = 0.999277 specular = 0.5 sky = 0.997832 $GPRMC,230013,A,0000.000,N,00000.000,E,000.0,000.0,0107102,0.000,E*40 $GPGGA,230013,0000.000,N,00000.000,E,1,,,00,F,,,,*19 $PATLA,115.80,280.0,115.80,280.0,379*59 Error writing to socket: 5500 Error writing data. load() base search path = /usr/src/games/fgfs/Scenery-0.9.2 Loading tile /usr/src/games/fgfs/Scenery-0.9.2/w010n00/w001n00/2938511 Updating Sun position Gst = 17.5724 t->cur_time = 1025564413 Sun Geodetic lat = 0.402627 Geocentric lat = 0.400212 sun angle relative to current location = 0.654801 Updating Moon position t->cur_time = 1025564413 Moon Geodetic lat = -0.0710015 Geocentric lat = -0.0705277 moon angle relative to current location = 2.24961 Updating light parameters. Sun angle = 37.5174 ambient = 0.2 diffuse = 1 specular = 0.5 sky = 1 _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel