From ccfde6914a5c8d76fcf81d2cdd79fd6ef8336338 Mon Sep 17 00:00:00 2001
From: Christian Schmitt <chris@ilovelinux.de>
Date: Fri, 14 Sep 2012 12:41:16 +0200
Subject: [PATCH] Linear features: Yellow hold lights are unidirectional to the
 right of the line direction. Implement this by creating a directional normal
 for these types.

---
 src/Airports/GenAirports850/linearfeature.cxx | 27 ++++++++++++++++---
 src/Airports/GenAirports850/linearfeature.hxx |  5 ++++
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/src/Airports/GenAirports850/linearfeature.cxx b/src/Airports/GenAirports850/linearfeature.cxx
index 174a0cd6..4d548810 100644
--- a/src/Airports/GenAirports850/linearfeature.cxx
+++ b/src/Airports/GenAirports850/linearfeature.cxx
@@ -759,6 +759,7 @@ int LinearFeature::Finish( bool closed, unsigned int idx )
     {
         prev_outer = Point3D(0.0f, 0.0f, 0.0f);
         cur_light_dist = 0.0f;
+        bool directional_light = lights[i]->IsDirectional();
 
         // which material for this light
         switch( lights[i]->type )
@@ -839,10 +840,28 @@ int LinearFeature::Finish( bool closed, unsigned int idx )
                                     
                     poly.add_node(0, tmp);
 
-                    // calculate the normal
-                    Point3D vec = sgGeodToCart( tmp * SG_DEGREES_TO_RADIANS );
-                    double length = vec.distance3D( Point3D(0.0) );
-                    vec = vec / length;
+                    double length;
+                    Point3D vec;
+
+                    if ( !directional_light )
+                    {
+                        // calculate the omnidirectional normal
+                        vec = sgGeodToCart( tmp * SG_DEGREES_TO_RADIANS );
+                        length = vec.distance3D( Point3D(0.0) );
+                        vec = vec / length;
+                    } else
+                    {
+                        // calculate the directional normal
+                        double heading_vec = heading + 90.0;
+                        if (heading_vec > 360.0) { heading_vec -= 360.0; }
+                        geo_direct_wgs_84( tmp.y(), tmp.x(), heading_vec, 10, &pt_y, &pt_x, &az2 );
+                        Point3D cart1 = sgGeodToCart( tmp * SG_DEGREES_TO_RADIANS );
+                        Point3D cart2 = sgGeodToCart( Point3D(pt_x, pt_y, 0.0) * SG_DEGREES_TO_RADIANS );
+
+                        vec = cart2 - cart1;
+                        length = vec.distance3D( Point3D(0.0) );
+                        vec = vec / length;
+                    }
 
                     normals_poly.add_node(0, vec );
 
diff --git a/src/Airports/GenAirports850/linearfeature.hxx b/src/Airports/GenAirports850/linearfeature.hxx
index f122b1c2..8799280c 100644
--- a/src/Airports/GenAirports850/linearfeature.hxx
+++ b/src/Airports/GenAirports850/linearfeature.hxx
@@ -57,6 +57,11 @@ public:
     unsigned int type;
     unsigned int start_idx;
     unsigned int end_idx;
+
+    bool IsDirectional()
+    {
+        return (type == 103 || type == 104) ? true : false;
+    }
 };
 typedef std::vector <Lighting*> LightingList;