From 537fa6c6047b9f1aca7d62ceb5821bf9dd3e5c6c Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 10 Mar 2005 11:11:57 +0000
Subject: [PATCH] Added null pointer check to avoid crash

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

diff --git a/src/osgTerrain/DataSet.cpp b/src/osgTerrain/DataSet.cpp
index a21bbe4f4..1ddf78f3d 100644
--- a/src/osgTerrain/DataSet.cpp
+++ b/src/osgTerrain/DataSet.cpp
@@ -1873,6 +1873,10 @@ void DataSet::DestinationTile::equalizeEdge(Position position)
         layerNum<_imagery.size();
         ++layerNum)
     {
+        // do we have a image to equalize?
+        if (!_imagery[layerNum]._imagery.valid()) continue;
+        
+        // does the neighbouring tile have an image to equalize?
         if (layerNum>=tile2->_imagery.size()) continue;
         if (!(tile2->_imagery[layerNum]._imagery.valid())) continue;