From 72483d565bfcfde43e63290b49aa8c33900d6d1c Mon Sep 17 00:00:00 2001
From: Torsten Dreyer <Torsten@t3r.de>
Date: Wed, 1 Feb 2012 22:24:06 +0100
Subject: [PATCH] initialize the heading-indicator/offset-deg in it's class

Don't initialize the offset in the main loop but in
the init method of the implementing class. This ensures
it gets initialized if you instantiate more than one
heading-indicator and does not initialize the property for
unsused heading-indicators (no more stray heading-indicator-fg
property anymore).
---
 src/Instrumentation/heading_indicator.cxx    | 6 +++++-
 src/Instrumentation/heading_indicator_fg.cxx | 7 ++++++-
 src/Main/main.cxx                            | 3 ---
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/Instrumentation/heading_indicator.cxx b/src/Instrumentation/heading_indicator.cxx
index e4b0c2438..2cbbb9f24 100644
--- a/src/Instrumentation/heading_indicator.cxx
+++ b/src/Instrumentation/heading_indicator.cxx
@@ -17,6 +17,7 @@
 #include <Main/fg_props.hxx>
 #include <Main/util.hxx>
 
+#include <simgear/magvar/magvar.hxx>
 
 HeadingIndicator::HeadingIndicator ( SGPropertyNode *node )
     :
@@ -37,7 +38,10 @@ HeadingIndicator::init ()
     branch = "/instrumentation/" + _name;
 
     SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
-    _offset_node = node->getChild("offset-deg", 0, true);
+    if( NULL == (_offset_node = node->getChild("offset-deg", 0, false)) ) {
+      _offset_node = node->getChild("offset-deg", 0, true);
+      _offset_node->setDoubleValue( -globals->get_mag()->get_magvar() * SGD_RADIANS_TO_DEGREES );
+    }
     _heading_in_node = fgGetNode("/orientation/heading-deg", true);
     _suction_node = fgGetNode(_suction.c_str(), true);
     _heading_out_node = node->getChild("indicated-heading-deg", 0, true);
diff --git a/src/Instrumentation/heading_indicator_fg.cxx b/src/Instrumentation/heading_indicator_fg.cxx
index dfa099c51..a485f5cdc 100644
--- a/src/Instrumentation/heading_indicator_fg.cxx
+++ b/src/Instrumentation/heading_indicator_fg.cxx
@@ -18,6 +18,8 @@
 #include <Main/fg_props.hxx>
 #include <Main/util.hxx>			    
 
+#include <simgear/magvar/magvar.hxx>
+
 using std::string;
 
 HeadingIndicatorFG::HeadingIndicatorFG ( SGPropertyNode *node )
@@ -60,7 +62,10 @@ HeadingIndicatorFG::init ()
 	_heading_in_node = fgGetNode("/orientation/heading-deg", true);
 
     SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
-    _offset_node = node->getChild("offset-deg", 0, true);
+    if( NULL == (_offset_node = node->getChild("offset-deg", 0, false)) ) {
+      _offset_node = node->getChild("offset-deg", 0, true);
+      _offset_node->setDoubleValue( -globals->get_mag()->get_magvar() * SGD_RADIANS_TO_DEGREES );
+    }
     _serviceable_node = node->getChild("serviceable", 0, true);
 	_error_node = node->getChild("heading-bug-error-deg", 0, true);
 	_nav1_error_node = node->getChild("nav1-course-error-deg", 0, true);
diff --git a/src/Main/main.cxx b/src/Main/main.cxx
index b4948b259..6e70ff894 100644
--- a/src/Main/main.cxx
+++ b/src/Main/main.cxx
@@ -387,9 +387,6 @@ static void fgIdleFunction ( void ) {
                                    fgGetDouble("/position/altitude-ft")
                                    * SG_FEET_TO_METER,
                                    globals->get_time_params()->getJD() );
-        double var = globals->get_mag()->get_magvar() * SGD_RADIANS_TO_DEGREES;
-        fgSetDouble("/instrumentation/heading-indicator/offset-deg", -var);
-        fgSetDouble("/instrumentation/heading-indicator-fg/offset-deg", -var);
 
         fgSplashProgress("initializing subsystems");
 
-- 
2.39.5