small fixes

simgear/environment/visual_enviro.cxx

@@ -755,8 +755,8 @@ void SGEnviro::drawLightning(void) {
 				ay = sin(course) * dist;
 				SGSharedPtr<SGSoundSample> snd = sampleGroup->find("thunder");
 				if( snd ) {
-					SGVec3f pos = SGVec3f(ax, ay, -sgEnviro.last_alt);
-					snd->set_relative_position(pos);
+					SGVec3d pos = SGVec3d(ax, ay, -sgEnviro.last_alt);
+					snd->set_position(pos);
 					snd->play_once();
 				}
 			}

simgear/sound/sample_group.cxx

@@ -114,7 +114,7 @@ void SGSampleGroup::update( double dt ) {
     }
 
     // Update the position and orientation information for all samples.
-    if ( _changed ) {
+    if ( _changed || _smgr->has_changed() ) {
         update_pos_and_orientation();
         _changed = false;
     }