1 files changed, 35 insertions, 3 deletions

diff --git a/OpenSim/Region/CoreModules/World/Terrain/TerrainModule.cs b/OpenSim/Region/CoreModules/World/Terrain/TerrainModule.cs
index 9766bfe..7bc5e88 100644
--- a/OpenSim/Region/CoreModules/World/Terrain/TerrainModule.cs
+++ b/OpenSim/Region/CoreModules/World/Terrain/TerrainModule.cs
@@ -314,12 +314,18 @@ namespace OpenSim.Region.CoreModules.World.Terrain
             LoadFromStream(filename, URIFetch(pathToTerrainHeightmap));
         }
 
+        public void LoadFromStream(string filename, Stream stream)
+        {
+            Vector2 defaultDisplacement = new Vector2(0f, 0f);
+            LoadFromStream(filename, defaultDisplacement, stream);
+        }
+
         /// <summary>
         /// Loads a terrain file from a stream and installs it in the scene.
         /// </summary>
         /// <param name="filename">Filename to terrain file. Type is determined by extension.</param>
         /// <param name="stream"></param>
-        public void LoadFromStream(string filename, Stream stream)
+        public void LoadFromStream(string filename, Vector2 displacement, Stream stream)
         {
             foreach (KeyValuePair<string, ITerrainLoader> loader in m_loaders)
             {
@@ -330,8 +336,7 @@ namespace OpenSim.Region.CoreModules.World.Terrain
                         try
                         {
                             ITerrainChannel channel = loader.Value.LoadStream(stream);
-                            m_scene.Heightmap = channel;
-                            m_channel = channel;
+                            MergeTerrainIntoExisting(channel, displacement);
                             UpdateRevertMap();
                         }
                         catch (NotImplementedException)
@@ -351,6 +356,33 @@ namespace OpenSim.Region.CoreModules.World.Terrain
             throw new TerrainException(String.Format("unable to load heightmap from file {0}: no loader available for that format", filename));
         }
 
+        private void MergeTerrainIntoExisting(ITerrainChannel channel, Vector2 displacement)
+        {
+            if (displacement == Vector2.Zero)
+            {
+                // If there is no displacement, just use this channel as the new heightmap
+                m_scene.Heightmap = channel;
+                m_channel = channel;
+            }
+            else
+            {
+                // If there is a displacement, we copy the loaded heightmap into the overall region
+                for (int xx = 0; xx < channel.Width; xx++)
+                {
+                    for (int yy = 0; yy < channel.Height; yy++)
+                    {
+                        int dispX = xx + (int)displacement.X;
+                        int dispY = yy + (int)displacement.Y;
+                        if (dispX >= 0 && dispX < m_channel.Width
+                                    && dispY >= 0 && dispY < m_channel.Height)
+                        {
+                            m_channel[dispX, dispY] = channel[xx, yy];
+                        }
+                    }
+                }
+            }
+        }
+
         private static Stream URIFetch(Uri uri)
         {
             HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);