From b8ddf517f4495219da7675d81bed59a378e2d78a Mon Sep 17 00:00:00 2001
From: Stuart Buchanan <stuart_d_buchanan@yahoo.co.uk>
Date: Thu, 14 Jan 2021 11:32:07 +0000
Subject: [PATCH] WS3.0 Add OBJECT STG entries as elevation constraints

Note this is for OBJECT only (e.g. airports), not
OBJECT_STATIC or OBJECT_SHARED
---
 simgear/scene/tgdb/ReaderWriterSTG.cxx | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/simgear/scene/tgdb/ReaderWriterSTG.cxx b/simgear/scene/tgdb/ReaderWriterSTG.cxx
index b9a0cb95..f7be485e 100644
--- a/simgear/scene/tgdb/ReaderWriterSTG.cxx
+++ b/simgear/scene/tgdb/ReaderWriterSTG.cxx
@@ -53,6 +53,8 @@
 #include <simgear/scene/material/matlib.hxx>
 #include <simgear/scene/tgdb/SGBuildingBin.hxx>
 #include <simgear/scene/tgdb/TreeBin.hxx>
+#include <simgear/scene/tgdb/VPBTechnique.hxx>
+
 
 #include <simgear/scene/util/SGSceneFeatures.hxx>
 
@@ -673,6 +675,11 @@ struct ReaderWriterSTG::_ModelBin {
                         << stgObject._token << " '" << stgObject._name << "'");
                     continue;
                 }
+
+                // Add the OBJECT to the elevation constraints of the terrain so the terrain
+                // doesn't poke through the airport
+                simgear::VPBTechnique::addElevationConstraint(node, terrainGroup);
+
                 terrainGroup->addChild(node.get());
             }
         } else if (_foundBase) {