From 1fdac74f8e60e2c6edcbd69d16e07e68a3bdb520 Mon Sep 17 00:00:00 2001
From: durk <durk>
Date: Wed, 10 Dec 2008 16:04:10 +0000
Subject: [PATCH] Minimize impact of distant AI models on the scene graph.

---
 src/AIModel/AIAircraft.cxx | 20 ++++++++++++++++++++
 src/AIModel/AIAircraft.hxx |  1 +
 2 files changed, 21 insertions(+)

diff --git a/src/AIModel/AIAircraft.cxx b/src/AIModel/AIAircraft.cxx
index d66eaa3ea..1ed6f7572 100644
--- a/src/AIModel/AIAircraft.cxx
+++ b/src/AIModel/AIAircraft.cxx
@@ -159,8 +159,28 @@ void FGAIAircraft::setPerformance(const std::string& acclass) {
      updateSecondaryTargetValues(); // target roll, vertical speed, pitch
      updateActualState(); 
      UpdateRadar(manager);
+     checkVisibility();
   }
 
+void FGAIAircraft::checkVisibility() 
+{
+     double visibility_meters = fgGetDouble("/environment/visibility-m");
+
+     FGViewer* vw = globals->get_current_view();
+     double course, distance;
+
+     SGWayPoint current(pos.getLongitudeDeg(), pos.getLatitudeDeg(), 0);
+     SGWayPoint view (vw->getLongitude_deg(), vw->getLatitude_deg(), 0);
+     view.CourseAndDistance(current, &course, &distance);
+     if (distance > visibility_meters) {
+         //aip.getSGLocation()->set_cur_elev_m(aptElev);
+         //return;
+         invisible = true;
+      } else {
+         invisible = false;
+      }
+}
+
 
 
 void FGAIAircraft::AccelTo(double speed) {
diff --git a/src/AIModel/AIAircraft.hxx b/src/AIModel/AIAircraft.hxx
index a179c9d7f..e391c6a45 100644
--- a/src/AIModel/AIAircraft.hxx
+++ b/src/AIModel/AIAircraft.hxx
@@ -126,6 +126,7 @@ private:
     void updatePitchAngleTarget();
     void updateActualState();
     void handleATCRequests();
+    void checkVisibility();
 
     double sign(double x);
 
-- 
2.39.5