From 83e21611f6ac9b1c69d2568570a590b77275752a Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 7 Apr 2005 10:55:17 +0000
Subject: [PATCH] Fixed sort of sources so that the layer number is taken into
 account.

---
 src/osgTerrain/DataSet.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/osgTerrain/DataSet.cpp b/src/osgTerrain/DataSet.cpp
index 92375e6b8..0b7733f6d 100644
--- a/src/osgTerrain/DataSet.cpp
+++ b/src/osgTerrain/DataSet.cpp
@@ -3842,7 +3842,10 @@ struct DerefLessFunctor
 {
     bool operator () (const T& lhs, const T& rhs)
     {
-        return (lhs.valid() && rhs.valid()) && (lhs->getSortValue() > rhs->getSortValue());
+        if (!lhs || !rhs) return lhs<rhs;
+        if (lhs->getLayer() < rhs->getLayer()) return true;
+        if (rhs->getLayer() < lhs->getLayer()) return false;
+        return (lhs->getSortValue() > rhs->getSortValue());
     }
 };