8 files changed, 1138 insertions, 125 deletions

diff --git a/OpenSim/Region/Framework/Interfaces/ISimulationDataStore.cs b/OpenSim/Region/Framework/Interfaces/ISimulationDataStore.cs
index 3787ca0..5ba5b31 100644
--- a/OpenSim/Region/Framework/Interfaces/ISimulationDataStore.cs
+++ b/OpenSim/Region/Framework/Interfaces/ISimulationDataStore.cs
@@ -135,4 +135,5 @@ namespace OpenSim.Region.Framework.Interfaces
 
         void Shutdown();
     }
+
 }
diff --git a/OpenSim/Region/Framework/Interfaces/ITerrainChannel.cs b/OpenSim/Region/Framework/Interfaces/ITerrainChannel.cs
index e467701..cc8a236 100644
--- a/OpenSim/Region/Framework/Interfaces/ITerrainChannel.cs
+++ b/OpenSim/Region/Framework/Interfaces/ITerrainChannel.cs
@@ -25,13 +25,20 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+using OpenSim.Framework;
+
 namespace OpenSim.Region.Framework.Interfaces
 {
     public interface ITerrainChannel
     {
-        int Height { get; }
+        int Width { get;}       // X dimension
+        int Height { get;}      // Y dimension
+        int Altitude { get;}    // Z dimension
+
         double this[int x, int y] { get; set; }
-        int Width { get; }
+
+        // Return the packaged terrain data for passing into lower levels of communication
+        TerrainData GetTerrainData();
 
         /// <summary>
         /// Squash the entire heightmap into a single dimensioned array
@@ -40,7 +47,10 @@ namespace OpenSim.Region.Framework.Interfaces
         float[] GetFloatsSerialised();
 
         double[,] GetDoubles();
+
+        // Check if a location has been updated. Clears the taint flag as a side effect.
         bool Tainted(int x, int y);
+
         ITerrainChannel MakeCopy();
         string SaveToXmlString();
         void LoadFromXmlString(string data);
diff --git a/OpenSim/Region/Framework/Scenes/Scene.cs b/OpenSim/Region/Framework/Scenes/Scene.cs
index 7772f94..e2880e3 100644
--- a/OpenSim/Region/Framework/Scenes/Scene.cs
+++ b/OpenSim/Region/Framework/Scenes/Scene.cs
@@ -1107,8 +1107,8 @@ namespace OpenSim.Region.Framework.Scenes
             if (RegionInfo.RegionHandle != otherRegion.RegionHandle)
             {
                 // If these are cast to INT because long + negative values + abs returns invalid data
-                int resultX = Math.Abs((int)xcell - (int)RegionInfo.RegionLocX);
-                int resultY = Math.Abs((int)ycell - (int)RegionInfo.RegionLocY);
+                int resultX = Math.Abs((int)xcell - (int)RegionInfo.LegacyRegionLocX);
+                int resultY = Math.Abs((int)ycell - (int)RegionInfo.LegacyRegionLocY);
                 if (resultX <= 1 && resultY <= 1)
                 {
                     // Let the grid service module know, so this can be cached
@@ -1183,8 +1183,8 @@ namespace OpenSim.Region.Framework.Scenes
         /// </returns>
         public int HaveNeighbor(Cardinals car, ref int[] fix)
         {
-            uint neighbourx = RegionInfo.RegionLocX;
-            uint neighboury = RegionInfo.RegionLocY;
+            uint neighbourx = RegionInfo.LegacyRegionLocX;
+            uint neighboury = RegionInfo.LegacyRegionLocY;
 
             int dir = (int)car;
 
@@ -1204,8 +1204,8 @@ namespace OpenSim.Region.Framework.Scenes
 
             if (neighbourRegion == null)
             {
-                fix[0] = (int)(RegionInfo.RegionLocX - neighbourx);
-                fix[1] = (int)(RegionInfo.RegionLocY - neighboury);
+                fix[0] = (int)(RegionInfo.LegacyRegionLocX - neighbourx);
+                fix[1] = (int)(RegionInfo.LegacyRegionLocY - neighboury);
                 return dir * (-1);
             }
             else
@@ -1905,13 +1905,13 @@ namespace OpenSim.Region.Framework.Scenes
                         m_InitialTerrain = terrainConfig.GetString("InitialTerrain", m_InitialTerrain);
 
                     m_log.InfoFormat("[TERRAIN]: No default terrain. Generating a new terrain {0}.", m_InitialTerrain);
-                    Heightmap = new TerrainChannel(m_InitialTerrain);
+                    Heightmap = new TerrainChannel(m_InitialTerrain, (int)RegionInfo.RegionSizeX, (int)RegionInfo.RegionSizeY, (int)RegionInfo.RegionSizeZ);
 
                     SimulationDataService.StoreTerrain(Heightmap.GetDoubles(), RegionInfo.RegionID);
                 }
                 else
                 {
-                    Heightmap = new TerrainChannel(map);
+                    Heightmap = new TerrainChannel(map, RegionInfo.RegionSizeZ);
                 }
             }
             catch (IOException e)
@@ -4371,8 +4371,8 @@ namespace OpenSim.Region.Framework.Scenes
                 {
                     uint rRegionX = (uint)(cAgentData.RegionHandle >> 40);
                     uint rRegionY = (((uint)(cAgentData.RegionHandle)) >> 8);
-                    uint tRegionX = RegionInfo.RegionLocX;
-                    uint tRegionY = RegionInfo.RegionLocY;
+                    uint tRegionX = RegionInfo.LegacyRegionLocX;
+                    uint tRegionY = RegionInfo.LegacyRegionLocY;
                     //Send Data to ScenePresence
                     childAgentUpdate.UpdateChildAgent(cAgentData, tRegionX, tRegionY, rRegionX, rRegionY);
                     // Not Implemented:
@@ -4600,13 +4600,13 @@ namespace OpenSim.Region.Framework.Scenes
             ScenePresence sp = GetScenePresence(remoteClient.AgentId);
             if (sp != null)
             {
-                uint regionX = RegionInfo.RegionLocX;
-                uint regionY = RegionInfo.RegionLocY;
+                uint regionX = RegionInfo.LegacyRegionLocX;
+                uint regionY = RegionInfo.LegacyRegionLocY;
 
                 Utils.LongToUInts(regionHandle, out regionX, out regionY);
 
-                int shiftx = (int) regionX - (int) RegionInfo.RegionLocX * (int)Constants.RegionSize;
-                int shifty = (int) regionY - (int) RegionInfo.RegionLocY * (int)Constants.RegionSize;
+                int shiftx = (int) regionX - (int) RegionInfo.LegacyRegionLocX * (int)Constants.RegionSize;
+                int shifty = (int) regionY - (int) RegionInfo.LegacyRegionLocY * (int)Constants.RegionSize;
 
                 position.X += shiftx;
                 position.Y += shifty;
diff --git a/OpenSim/Region/Framework/Scenes/SceneManager.cs b/OpenSim/Region/Framework/Scenes/SceneManager.cs
index 28f7896..2677989 100644
--- a/OpenSim/Region/Framework/Scenes/SceneManager.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneManager.cs
@@ -445,8 +445,8 @@ namespace OpenSim.Region.Framework.Scenes
             {
                 foreach (Scene mscene in m_localScenes)
                 {
-                    if (mscene.RegionInfo.RegionLocX == locX &&
-                        mscene.RegionInfo.RegionLocY == locY)
+                    if (mscene.RegionInfo.LegacyRegionLocX == locX &&
+                        mscene.RegionInfo.LegacyRegionLocY == locY)
                     {
                         scene = mscene;
                         return true;
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index 7243db1..297ee5f 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -710,7 +710,7 @@ namespace OpenSim.Region.Framework.Scenes
                 Utils.LongToUInts(handle, out x, out y);
                 x = x / Constants.RegionSize;
                 y = y / Constants.RegionSize;
-                if (Util.IsOutsideView(DrawDistance, x, Scene.RegionInfo.RegionLocX, y, Scene.RegionInfo.RegionLocY))
+                if (Util.IsOutsideView(DrawDistance, x, Scene.RegionInfo.LegacyRegionLocX, y, Scene.RegionInfo.LegacyRegionLocY))
                 {
                     old.Add(handle);
                 }
@@ -2094,8 +2094,8 @@ namespace OpenSim.Region.Framework.Scenes
 //            }
 
             // Get terrain height for sub-region in a megaregion if necessary
-            int X = (int)((m_scene.RegionInfo.RegionLocX * Constants.RegionSize) + pos.X);
-            int Y = (int)((m_scene.RegionInfo.RegionLocY * Constants.RegionSize) + pos.Y);
+            int X = (int)((m_scene.RegionInfo.RegionWorldLocX) + pos.X);
+            int Y = (int)((m_scene.RegionInfo.RegionWorldLocY) + pos.Y);
             GridRegion target_region = m_scene.GridService.GetRegionByPosition(m_scene.RegionInfo.ScopeID, X, Y);
             // If X and Y is NaN, target_region will be null
             if (target_region == null)
diff --git a/OpenSim/Region/Framework/Scenes/SimStatsReporter.cs b/OpenSim/Region/Framework/Scenes/SimStatsReporter.cs
index 95f9caf..67998a0 100644
--- a/OpenSim/Region/Framework/Scenes/SimStatsReporter.cs
+++ b/OpenSim/Region/Framework/Scenes/SimStatsReporter.cs
@@ -437,7 +437,7 @@ namespace OpenSim.Region.Framework.Scenes
               
                 SimStats simStats 
                     = new SimStats(
-                        ReportingRegion.RegionLocX, ReportingRegion.RegionLocY, regionFlags, (uint)m_objectCapacity,
+                        ReportingRegion.LegacyRegionLocX, ReportingRegion.LegacyRegionLocY, regionFlags, (uint)m_objectCapacity,
                         rb, sb, m_scene.RegionInfo.originRegionID);
 
                 handlerSendStatResult = OnSendStatsResult;
diff --git a/OpenSim/Region/Framework/Scenes/TerrainChannel.cs b/OpenSim/Region/Framework/Scenes/TerrainChannel.cs
index c0ca48e..6d245cb 100644
--- a/OpenSim/Region/Framework/Scenes/TerrainChannel.cs
+++ b/OpenSim/Region/Framework/Scenes/TerrainChannel.cs
@@ -25,14 +25,19 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-using OpenSim.Framework;
-using OpenSim.Region.Framework.Interfaces;
 using System;
+using System.IO;
 using System.Text;
+using System.Reflection;
 using System.Xml;
-using System.IO;
 using System.Xml.Serialization;
 
+using OpenSim.Data;
+using OpenSim.Framework;
+using OpenSim.Region.Framework.Interfaces;
+
+using log4net;
+
 namespace OpenSim.Region.Framework.Scenes
 {
     /// <summary>
@@ -40,132 +45,115 @@ namespace OpenSim.Region.Framework.Scenes
     /// </summary>
     public class TerrainChannel : ITerrainChannel
     {
-        private readonly bool[,] taint;
-        private double[,] map;
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private static string LogHeader = "[TERRAIN CHANNEL]";
+
+        protected TerrainData m_terrainData;
 
+        public int Width { get { return m_terrainData.SizeX; } }  // X dimension
+        // Unfortunately, for historical reasons, in this module 'Width' is X and 'Height' is Y
+        public int Height { get { return m_terrainData.SizeY; } } // Y dimension
+        public int Altitude { get { return m_terrainData.SizeZ; } } // Y dimension
+
+        // Default, not-often-used builder
         public TerrainChannel()
         {
-            map = new double[Constants.RegionSize, Constants.RegionSize];
-            taint = new bool[Constants.RegionSize / 16, Constants.RegionSize / 16];
-
-            PinHeadIsland();
+            m_terrainData = new HeightmapTerrainData((int)Constants.RegionSize, (int)Constants.RegionSize, (int)Constants.RegionHeight);
+            FlatLand();
+            // PinHeadIsland();
         }
 
-        public TerrainChannel(String type)
+        // Create terrain of given size
+        public TerrainChannel(int pX, int pY)
         {
-            map = new double[Constants.RegionSize, Constants.RegionSize];
-            taint = new bool[Constants.RegionSize / 16, Constants.RegionSize / 16];
+            m_terrainData = new HeightmapTerrainData(pX, pY, (int)Constants.RegionHeight);
+        }
 
+        // Create terrain of specified size and initialize with specified terrain.
+        // TODO: join this with the terrain initializers.
+        public TerrainChannel(String type, int pX, int pY, int pZ)
+        {
+            m_terrainData = new HeightmapTerrainData(pX, pY, pZ);
             if (type.Equals("flat"))
                 FlatLand();
             else
                 PinHeadIsland();
         }
 
-        public TerrainChannel(double[,] import)
-        {
-            map = import;
-            taint = new bool[import.GetLength(0),import.GetLength(1)];
-        }
-
-        public TerrainChannel(bool createMap)
-        {
-            if (createMap)
-            {
-                map = new double[Constants.RegionSize,Constants.RegionSize];
-                taint = new bool[Constants.RegionSize / 16,Constants.RegionSize / 16];
-            }
-        }
-
-        public TerrainChannel(int w, int h)
+        public TerrainChannel(double[,] pM, uint pAltitude)
         {
-            map = new double[w,h];
-            taint = new bool[w / 16,h / 16];
+            m_terrainData = new HeightmapTerrainData(pM);
         }
 
         #region ITerrainChannel Members
 
-        public int Width
+        // ITerrainChannel.MakeCopy()
+        public ITerrainChannel MakeCopy()
         {
-            get { return map.GetLength(0); }
+            return this.Copy();
         }
 
-        public int Height
+        // ITerrainChannel.GetTerrainData()
+        public TerrainData GetTerrainData()
         {
-            get { return map.GetLength(1); }
+            return m_terrainData;
         }
 
-        public ITerrainChannel MakeCopy()
+        // ITerrainChannel.GetFloatsSerialized()
+        // NOTICE that the one dimensional form is ordered by Y!!
+        public float[] GetFloatsSerialised()
         {
-            TerrainChannel copy = new TerrainChannel(false);
-            copy.map = (double[,]) map.Clone();
+            int points = Width * Height;
+            float[] heights = new float[points];
 
-            return copy;
+            int idx = 0;
+            for (int ii = 0; ii < Height; ii++)
+                for (int jj = 0; jj < Width; jj++)
+                    heights[idx++] = m_terrainData[jj, ii];
+
+            return heights;
         }
 
-        public float[] GetFloatsSerialised()
+        // ITerrainChannel.GetDoubles()
+        public double[,] GetDoubles()
         {
-            // Move the member variables into local variables, calling
-            // member variables 256*256 times gets expensive
             int w = Width;
-            int h = Height;
-            float[] heights = new float[w * h];
+            int l = Height;
+            double[,] heights = new double[w, l];
 
-            int i, j; // map coordinates
             int idx = 0; // index into serialized array
-            for (i = 0; i < h; i++)
+            for (int ii = 0; ii < w; ii++)
             {
-                for (j = 0; j < w; j++)
+                for (int jj = 0; jj < l; jj++)
                 {
-                    heights[idx++] = (float)map[j, i];
+                    heights[ii, jj] = (double)m_terrainData[ii, jj];
+                    idx++;
                 }
             }
 
             return heights;
         }
 
-        public double[,] GetDoubles()
-        {
-            return map;
-        }
-
+        // ITerrainChannel.this[x,y]
         public double this[int x, int y]
         {
-            get { return map[x, y]; }
+            get { return (double)m_terrainData[x, y]; }
             set
             {
-                // Will "fix" terrain hole problems. Although not fantastically.
                 if (Double.IsNaN(value) || Double.IsInfinity(value))
                     return;
 
-                if (map[x, y] != value)
-                {
-                    taint[x / 16, y / 16] = true;
-                    map[x, y] = value;
-                }
+                m_terrainData[x, y] = (float)value;
             }
         }
 
+        // ITerrainChannel.Tainted()
         public bool Tainted(int x, int y)
         {
-            if (taint[x / 16, y / 16])
-            {
-                taint[x / 16, y / 16] = false;
-                return true;
-            }
-            return false;
-        }
-
-        #endregion
-
-        public TerrainChannel Copy()
-        {
-            TerrainChannel copy = new TerrainChannel(false);
-            copy.map = (double[,]) map.Clone();
-
-            return copy;
+            return m_terrainData.IsTaintedAt(x, y);
         }
 
+        // ITerrainChannel.SaveToXmlString()
         public string SaveToXmlString()
         {
             XmlWriterSettings settings = new XmlWriterSettings();
@@ -181,13 +169,7 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
-        private void WriteXml(XmlWriter writer)
-        {
-            writer.WriteStartElement(String.Empty, "TerrainMap", String.Empty);
-            ToXml(writer);
-            writer.WriteEndElement();
-        }
-
+        // ITerrainChannel.LoadFromXmlString()
         public void LoadFromXmlString(string data)
         {
             StringReader sr = new StringReader(data);
@@ -199,12 +181,50 @@ namespace OpenSim.Region.Framework.Scenes
             sr.Close();
         }
 
+        #endregion
+
+        public TerrainChannel Copy()
+        {
+            TerrainChannel copy = new TerrainChannel();
+            copy.m_terrainData = m_terrainData.Clone();
+            return copy;
+        }
+
+        private void WriteXml(XmlWriter writer)
+        {
+            if (Width == Constants.RegionSize && Height == Constants.RegionSize)
+            {
+                // Downward compatibility for legacy region terrain maps.
+                // If region is exactly legacy size, return the old format XML.
+                writer.WriteStartElement(String.Empty, "TerrainMap", String.Empty);
+                ToXml(writer);
+                writer.WriteEndElement();
+            }
+            else
+            {
+                // New format XML that includes width and length.
+                writer.WriteStartElement(String.Empty, "TerrainMap2", String.Empty);
+                ToXml2(writer);
+                writer.WriteEndElement();
+            }
+        }
+
         private void ReadXml(XmlReader reader)
         {
-            reader.ReadStartElement("TerrainMap");
-            FromXml(reader);
+            // Check the first element. If legacy element, use the legacy reader.
+            if (reader.IsStartElement("TerrainMap"))
+            {
+                reader.ReadStartElement("TerrainMap");
+                FromXml(reader);
+            }
+            else
+            {
+                reader.ReadStartElement("TerrainMap2");
+                FromXml2(reader);
+            }
         }
 
+        // Write legacy terrain map. Presumed to be 256x256 of data encoded as floats in a byte array.
         private void ToXml(XmlWriter xmlWriter)
         {
             float[] mapData = GetFloatsSerialised();
@@ -218,12 +238,15 @@ namespace OpenSim.Region.Framework.Scenes
             serializer.Serialize(xmlWriter, buffer);
         }
 
+        // Read legacy terrain map. Presumed to be 256x256 of data encoded as floats in a byte array.
         private void FromXml(XmlReader xmlReader)
         {
             XmlSerializer serializer = new XmlSerializer(typeof(byte[]));
             byte[] dataArray = (byte[])serializer.Deserialize(xmlReader);
             int index = 0;
 
+            m_terrainData = new HeightmapTerrainData(Width, Height, Altitude);
+            
             for (int y = 0; y < Height; y++)
             {
                 for (int x = 0; x < Width; x++)
@@ -236,35 +259,65 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
+        private class TerrainChannelXMLPackage
+        {
+            public int Version;
+            public int SizeX;
+            public int SizeY;
+            public int SizeZ;
+            public float CompressionFactor;
+            public short[] Map;
+            public TerrainChannelXMLPackage(int pX, int pY, int pZ, float pCompressionFactor, short[] pMap)
+            {
+                Version = 1;
+                SizeX = pX;
+                SizeY = pY;
+                SizeZ = pZ;
+                CompressionFactor = pCompressionFactor;
+                Map = pMap;
+            }
+        }
+
+        // New terrain serialization format that includes the width and length.
+        private void ToXml2(XmlWriter xmlWriter)
+        {
+            TerrainChannelXMLPackage package = new TerrainChannelXMLPackage(Width, Height, Altitude, m_terrainData.CompressionFactor,
+                                            m_terrainData.GetCompressedMap());
+            XmlSerializer serializer = new XmlSerializer(typeof(TerrainChannelXMLPackage));
+            serializer.Serialize(xmlWriter, package);
+        }
+
+        // New terrain serialization format that includes the width and length.
+        private void FromXml2(XmlReader xmlReader)
+        {
+            XmlSerializer serializer = new XmlSerializer(typeof(TerrainChannelXMLPackage));
+            TerrainChannelXMLPackage package = (TerrainChannelXMLPackage)serializer.Deserialize(xmlReader);
+            m_terrainData = new HeightmapTerrainData(package.Map, package.CompressionFactor, package.SizeX, package.SizeY, package.SizeZ);
+        }
+
+        // Fill the heightmap with the center bump terrain
         private void PinHeadIsland()
         {
-            int x;
-            for (x = 0; x < Constants.RegionSize; x++)
+            for (int x = 0; x < Width; x++)
             {
-                int y;
-                for (y = 0; y < Constants.RegionSize; y++)
+                for (int y = 0; y < Height; y++)
                 {
-                    map[x, y] = TerrainUtil.PerlinNoise2D(x, y, 2, 0.125) * 10;
-                    double spherFacA = TerrainUtil.SphericalFactor(x, y, Constants.RegionSize / 2.0, Constants.RegionSize / 2.0, 50) * 0.01;
-                    double spherFacB = TerrainUtil.SphericalFactor(x, y, Constants.RegionSize / 2.0, Constants.RegionSize / 2.0, 100) * 0.001;
-                    if (map[x, y] < spherFacA)
-                        map[x, y] = spherFacA;
-                    if (map[x, y] < spherFacB)
-                        map[x, y] = spherFacB;
+                    m_terrainData[x, y] = (float)TerrainUtil.PerlinNoise2D(x, y, 2, 0.125) * 10;
+                    float spherFacA = (float)(TerrainUtil.SphericalFactor(x, y, m_terrainData.SizeX / 2.0, m_terrainData.SizeY / 2.0, 50) * 0.01d);
+                    float spherFacB = (float)(TerrainUtil.SphericalFactor(x, y, m_terrainData.SizeX / 2.0, m_terrainData.SizeY / 2.0, 100) * 0.001d);
+                    if (m_terrainData[x, y]< spherFacA)
+                        m_terrainData[x, y]= spherFacA;
+                    if (m_terrainData[x, y]< spherFacB)
+                        m_terrainData[x, y] = spherFacB;
                 }
             }
         }
 
         private void FlatLand()
         {
-            int x;
-            for (x = 0; x < Constants.RegionSize; x++)
-            {
-                int y;
-                for (y = 0; y < Constants.RegionSize; y++)
-                    map[x, y] = 21;
-            }
+            for (int xx = 0; xx < Width; xx++)
+                for (int yy = 0; yy < Height; yy++)
+                    m_terrainData[xx, yy] = 21;
         }
-
     }
 }
diff --git a/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs b/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs
new file mode 100644
index 0000000..e91c959
--- /dev/null
+++ b/OpenSim/Region/Framework/Scenes/TerrainCompressor.cs
@@ -0,0 +1,949 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* Freely adapted from the Aurora version of the terrain compressor.
+ * Copyright (c) Contributors, http://aurora-sim.org/, http://opensimulator.org/
+ */
+
+using System;
+using System.Reflection;
+
+using log4net;
+
+using OpenSim.Framework;
+using OpenSim.Region.Framework;
+using OpenSim.Region.Framework.Scenes;
+
+using OpenMetaverse;
+using OpenMetaverse.Packets;
+
+namespace OpenSim.Region.ClientStack.LindenUDP
+{
+    public static class OpenSimTerrainCompressor
+    {
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private static string LogHeader = "[TERRAIN COMPRESSOR]";
+
+        public const int END_OF_PATCHES = 97;
+
+        private const float OO_SQRT2 = 0.7071067811865475244008443621049f;
+        private const int STRIDE = 264;
+
+        private const int ZERO_CODE = 0x0;
+        private const int ZERO_EOB = 0x2;
+        private const int POSITIVE_VALUE = 0x6;
+        private const int NEGATIVE_VALUE = 0x7;
+
+        private static readonly float[] DequantizeTable16 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] DequantizeTable32 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] CosineTable16 = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+        //private static readonly float[] CosineTable32 = new float[Constants.TerrainPatchSize * Constants.TerrainPatchSize];
+        private static readonly int[] CopyMatrix16 = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+        private static readonly int[] CopyMatrix32 = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        private static readonly float[] QuantizeTable16 =
+            new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+        static OpenSimTerrainCompressor()
+        {
+            // Initialize the decompression tables
+            BuildDequantizeTable16();
+            SetupCosines16();
+            BuildCopyMatrix16();
+            BuildQuantizeTable16();
+        }
+
+        // Unused: left for historical reference.
+        public static LayerDataPacket CreateLayerDataPacket(TerrainPatch[] patches, byte type, int pRegionSizeX,
+                                                            int pRegionSizeY)
+        {
+            LayerDataPacket layer = new LayerDataPacket {LayerID = {Type = type}};
+
+            TerrainPatch.GroupHeader header = new TerrainPatch.GroupHeader
+                                                  {Stride = STRIDE, PatchSize = Constants.TerrainPatchSize};
+
+            // Should be enough to fit even the most poorly packed data
+            byte[] data = new byte[patches.Length*Constants.TerrainPatchSize*Constants.TerrainPatchSize*2];
+            BitPack bitpack = new BitPack(data, 0);
+            bitpack.PackBits(header.Stride, 16);
+            bitpack.PackBits(header.PatchSize, 8);
+            bitpack.PackBits(type, 8);
+
+            foreach (TerrainPatch t in patches)
+                CreatePatch(bitpack, t.Data, t.X, t.Y, pRegionSizeX, pRegionSizeY);
+
+            bitpack.PackBits(END_OF_PATCHES, 8);
+
+            layer.LayerData.Data = new byte[bitpack.BytePos + 1];
+            Buffer.BlockCopy(bitpack.Data, 0, layer.LayerData.Data, 0, bitpack.BytePos + 1);
+
+            return layer;
+        }
+
+        // Legacy land packet generation gluing old land representation (heights) to compressed representation.
+        // This is an intermediate step in converting terrain into a variable sized heightmap. Some of the
+        //     routines (like IClientAPI) only pass the float array of heights around. This entry
+        //     converts that legacy representation into the more compact represenation used in
+        //     TerrainData. Someday fix the plumbing between here and the scene.
+        public static LayerDataPacket CreateLandPacket(TerrainData terrData, int patchX, int patchY)
+        {
+            int[] xPieces = new int[1];
+            int[] yPieces = new int[1];
+            xPieces[0] = patchX;  // patch X dimension
+            yPieces[0] = patchY;
+
+            m_log.DebugFormat("{0} CreateLandPacket. patchX={1}, patchY={2}, sizeX={3}, sizeY={4}",
+                                    LogHeader, patchX, patchY, terrData.SizeX, terrData.SizeY);
+
+            return CreateLandPacket(terrData, xPieces, yPieces, (int)TerrainPatch.LayerType.Land);
+        }
+
+        /// <summary>
+        ///     Creates a LayerData packet for compressed land data given a full
+        ///     simulator heightmap and an array of indices of patches to compress
+        /// </summary>
+        /// <param name="heightmap">
+        ///     A 256 * 256 array of floating point values
+        ///     specifying the height at each meter in the simulator
+        /// </param>
+        /// <param name="x">
+        ///     Array of indexes in the 16x16 grid of patches
+        ///     for this simulator. For example if 1 and 17 are specified, patches
+        ///     x=1,y=0 and x=1,y=1 are sent
+        /// </param>
+        /// <param name="y">
+        ///     Array of indexes in the 16x16 grid of patches
+        ///     for this simulator. For example if 1 and 17 are specified, patches
+        ///     x=1,y=0 and x=1,y=1 are sent
+        /// </param>
+        /// <param name="type"></param>
+        /// <param name="pRegionSizeX"></param>
+        /// <param name="pRegionSizeY"></param>
+        /// <returns></returns>
+        public static LayerDataPacket CreateLandPacket(TerrainData terrData, int[] x, int[] y, byte type)
+        {
+            LayerDataPacket layer = new LayerDataPacket {LayerID = {Type = type}};
+
+            TerrainPatch.GroupHeader header = new TerrainPatch.GroupHeader
+                                                  {Stride = STRIDE, PatchSize = Constants.TerrainPatchSize};
+
+            byte[] data = new byte[x.Length * Constants.TerrainPatchSize * Constants.TerrainPatchSize * 2];
+            BitPack bitpack = new BitPack(data, 0);
+            bitpack.PackBits(header.Stride, 16);
+            bitpack.PackBits(header.PatchSize, 8);
+            bitpack.PackBits(type, 8);
+
+            for (int i = 0; i < x.Length; i++)
+                CreatePatchFromHeightmap(bitpack, terrData, x[i], y[i]);
+
+            bitpack.PackBits(END_OF_PATCHES, 8);
+
+            layer.LayerData.Data = new byte[bitpack.BytePos + 1];
+            Buffer.BlockCopy(bitpack.Data, 0, layer.LayerData.Data, 0, bitpack.BytePos + 1);
+
+            return layer;
+        }
+
+        // Unused: left for historical reference.
+        public static void CreatePatch(BitPack output, float[] patchData, int x, int y, int pRegionSizeX, int pRegionSizeY)
+        {
+            TerrainPatch.Header header = PrescanPatch(patchData);
+            header.QuantWBits = 136;
+            if (pRegionSizeX > Constants.RegionSize || pRegionSizeY > Constants.RegionSize)
+            {
+                header.PatchIDs = (y & 0xFFFF);
+                header.PatchIDs += (x << 16);
+            }
+            else
+            {
+                header.PatchIDs = (y & 0x1F);
+                header.PatchIDs += (x << 5);
+            }
+
+            // NOTE: No idea what prequant and postquant should be or what they do
+
+            int wbits;
+            int[] patch = CompressPatch(patchData, header, 10, out wbits);
+            wbits = EncodePatchHeader(output, header, patch, Constants.RegionSize, Constants.RegionSize, wbits);
+            EncodePatch(output, patch, 0, wbits);
+        }
+
+        /// <summary>
+        ///     Add a patch of terrain to a BitPacker
+        /// </summary>
+        /// <param name="output">BitPacker to write the patch to</param>
+        /// <param name="heightmap">
+        ///     Heightmap of the simulator. Presumed to be an sizeX*sizeY array.
+        /// </param>
+        /// <param name="patchX">
+        ///     X offset of the patch to create.
+        /// </param>
+        /// <param name="patchY">
+        ///     Y offset of the patch to create.
+        /// </param>
+        /// <param name="pRegionSizeX"></param>
+        /// <param name="pRegionSizeY"></param>
+        public static void CreatePatchFromHeightmap(BitPack output, TerrainData terrData, int patchX, int patchY)
+        {
+            TerrainPatch.Header header = PrescanPatch(terrData, patchX, patchY);
+            header.QuantWBits = 136;
+
+            // If larger than legacy region size, pack patch X and Y info differently.
+            if (terrData.SizeX > Constants.RegionSize || terrData.SizeY > Constants.RegionSize)
+            {
+                header.PatchIDs = (patchY & 0xFFFF);
+                header.PatchIDs += (patchX << 16);
+            }
+            else
+            {
+                header.PatchIDs = (patchY & 0x1F);
+                header.PatchIDs += (patchX << 5);
+            }
+
+            // NOTE: No idea what prequant and postquant should be or what they do
+            int wbits;
+            int[] patch = CompressPatch(terrData, patchX, patchY, header, 10, out wbits);
+            wbits = EncodePatchHeader(output, header, patch, (uint)terrData.SizeX, (uint)terrData.SizeY, wbits);
+            EncodePatch(output, patch, 0, wbits);
+        }
+
+        private static TerrainPatch.Header PrescanPatch(float[] patch)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header();
+            float zmax = -99999999.0f;
+            float zmin = 99999999.0f;
+
+            for (int i = 0; i < Constants.TerrainPatchSize*Constants.TerrainPatchSize; i++)
+            {
+                float val = patch[i];
+                if (val > zmax) zmax = val;
+                if (val < zmin) zmin = val;
+            }
+
+            header.DCOffset = zmin;
+            header.Range = (int) ((zmax - zmin) + 1.0f);
+
+            return header;
+        }
+
+        // Scan the height info we're returning and return a patch packet header for this patch.
+        private static TerrainPatch.Header PrescanPatch(TerrainData terrData, int patchX, int patchY)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header();
+            float zmax = -99999999.0f;
+            float zmin = 99999999.0f;
+
+            for (int j = patchY*16; j < (patchY + 1)*16; j++)
+            {
+                for (int i = patchX*16; i < (patchX + 1)*16; i++)
+                {
+                    // short val = heightmap[j*pRegionSizeX + i];
+                    float val = terrData[j, i];
+                    if (val > zmax) zmax = val;
+                    if (val < zmin) zmin = val;
+                }
+            }
+
+            // Since the the min and max values are the shorts, rescale to be real values.
+            // TODO: all this logic should go into the class wrapping the short values.
+            header.DCOffset = zmin;
+            header.Range = (int)(zmax - zmin + 1.0f);
+
+            return header;
+        }
+
+        public static TerrainPatch.Header DecodePatchHeader(BitPack bitpack)
+        {
+            TerrainPatch.Header header = new TerrainPatch.Header {QuantWBits = bitpack.UnpackBits(8)};
+
+            // Quantized word bits
+            if (header.QuantWBits == END_OF_PATCHES)
+                return header;
+
+            // DC offset
+            header.DCOffset = bitpack.UnpackFloat();
+
+            // Range
+            header.Range = bitpack.UnpackBits(16);
+
+            // Patch IDs (10 bits)
+            header.PatchIDs = bitpack.UnpackBits(10);
+
+            // Word bits
+            header.WordBits = (uint) ((header.QuantWBits & 0x0f) + 2);
+
+            return header;
+        }
+
+        private static int EncodePatchHeader(BitPack output, TerrainPatch.Header header, int[] patch, uint pRegionSizeX,
+                                             uint pRegionSizeY, int wbits)
+        {
+            /*
+                    int temp;
+                    int wbits = (header.QuantWBits & 0x0f) + 2;
+                    uint maxWbits = (uint)wbits + 5;
+                    uint minWbits = ((uint)wbits >> 1);
+                    int wbitsMaxValue;
+        */
+            // goal is to determ minimum number of bits to use so all data fits
+            /*
+                    wbits = (int)minWbits;
+                    wbitsMaxValue = (1 << wbits);
+
+                    for (int i = 0; i < patch.Length; i++)
+                    {
+                        temp = patch[i];
+                        if (temp != 0)
+                        {
+                            // Get the absolute value
+                            if (temp < 0) temp *= -1;
+
+         no coments..
+
+                            for (int j = (int)maxWbits; j > (int)minWbits; j--)
+                            {
+                                if ((temp & (1 << j)) != 0)
+                                {
+                                    if (j > wbits) wbits = j;
+                                    break;
+                                }
+                            }
+ 
+                            while (temp > wbitsMaxValue)
+                                {
+                                wbits++;
+                                if (wbits == maxWbits)
+                                    goto Done;
+                                wbitsMaxValue = 1 << wbits;
+                                }
+                        }
+                    }
+
+                Done:
+
+                    //            wbits += 1;
+         */
+            // better check
+            if (wbits > 17)
+                wbits = 16;
+            else if (wbits < 3)
+                wbits = 3;
+
+            header.QuantWBits &= 0xf0;
+
+            header.QuantWBits |= (wbits - 2);
+
+            output.PackBits(header.QuantWBits, 8);
+            output.PackFloat(header.DCOffset);
+            output.PackBits(header.Range, 16);
+            if (pRegionSizeX > Constants.RegionSize || pRegionSizeY > Constants.RegionSize)
+                output.PackBits(header.PatchIDs, 32);
+            else
+                output.PackBits(header.PatchIDs, 10);
+
+            return wbits;
+        }
+
+        private static void IDCTColumn16(float[] linein, float[] lineout, int column)
+        {
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                float total = OO_SQRT2*linein[column];
+
+                for (int u = 1; u < Constants.TerrainPatchSize; u++)
+                {
+                    int usize = u*Constants.TerrainPatchSize;
+                    total += linein[usize + column]*CosineTable16[usize + n];
+                }
+
+                lineout[Constants.TerrainPatchSize*n + column] = total;
+            }
+        }
+
+        private static void IDCTLine16(float[] linein, float[] lineout, int line)
+        {
+            const float oosob = 2.0f/Constants.TerrainPatchSize;
+            int lineSize = line*Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                float total = OO_SQRT2*linein[lineSize];
+
+                for (int u = 1; u < Constants.TerrainPatchSize; u++)
+                {
+                    total += linein[lineSize + u]*CosineTable16[u*Constants.TerrainPatchSize + n];
+                }
+
+                lineout[lineSize + n] = total*oosob;
+            }
+        }
+
+/*
+        private static void DCTLine16(float[] linein, float[] lineout, int line)
+        {
+            float total = 0.0f;
+            int lineSize = line * Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[lineSize + n];
+            }
+
+            lineout[lineSize] = OO_SQRT2 * total;
+
+            int uptr = 0;
+            for (int u = 1; u < Constants.TerrainPatchSize; u++)
+            {
+                total = 0.0f;
+                uptr += Constants.TerrainPatchSize;
+
+                for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                {
+                    total += linein[lineSize + n] * CosineTable16[uptr + n];
+                }
+
+                lineout[lineSize + u] = total;
+            }
+        }
+*/
+
+        private static void DCTLine16(float[] linein, float[] lineout, int line)
+        {
+            // outputs transpose data (lines exchanged with coluns )
+            // so to save a bit of cpu when doing coluns
+            float total = 0.0f;
+            int lineSize = line*Constants.TerrainPatchSize;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[lineSize + n];
+            }
+
+            lineout[line] = OO_SQRT2*total;
+
+            for (int u = Constants.TerrainPatchSize;
+                 u < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 u += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+                for (int ptrn = lineSize, ptru = u; ptrn < lineSize + Constants.TerrainPatchSize; ptrn++,ptru++)
+                {
+                    total += linein[ptrn]*CosineTable16[ptru];
+                }
+
+                lineout[line + u] = total;
+            }
+        }
+
+
+        /*
+                private static void DCTColumn16(float[] linein, int[] lineout, int column)
+                {
+                    float total = 0.0f;
+        //            const float oosob = 2.0f / Constants.TerrainPatchSize;
+
+                    for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                    {
+                        total += linein[Constants.TerrainPatchSize * n + column];
+                    }
+
+        //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+                    lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * QuantizeTable16[column]);
+
+                    for (int uptr = Constants.TerrainPatchSize; uptr < Constants.TerrainPatchSize * Constants.TerrainPatchSize; uptr += Constants.TerrainPatchSize)
+                    {
+                        total = 0.0f;
+
+                        for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                        {
+                            total += linein[Constants.TerrainPatchSize * n + column] * CosineTable16[uptr + n];
+                        }
+
+        //                lineout[CopyMatrix16[Constants.TerrainPatchSize * u + column]] = (int)(total * oosob * QuantizeTable16[Constants.TerrainPatchSize * u + column]);
+                        lineout[CopyMatrix16[uptr + column]] = (int)(total * QuantizeTable16[uptr + column]);
+                        }
+                }
+        */
+
+        private static void DCTColumn16(float[] linein, int[] lineout, int column)
+        {
+            // input columns are in fact stored in lines now
+
+            float total = 0.0f;
+//            const float oosob = 2.0f / Constants.TerrainPatchSize;
+            int inlinesptr = Constants.TerrainPatchSize*column;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[inlinesptr + n];
+            }
+
+            //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+            lineout[CopyMatrix16[column]] = (int) (OO_SQRT2*total*QuantizeTable16[column]);
+
+            for (int uptr = Constants.TerrainPatchSize;
+                 uptr < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 uptr += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+
+                for (int n = inlinesptr, ptru = uptr; n < inlinesptr + Constants.TerrainPatchSize; n++, ptru++)
+                {
+                    total += linein[n]*CosineTable16[ptru];
+                }
+
+//                lineout[CopyMatrix16[Constants.TerrainPatchSize * u + column]] = (int)(total * oosob * QuantizeTable16[Constants.TerrainPatchSize * u + column]);
+                lineout[CopyMatrix16[uptr + column]] = (int) (total*QuantizeTable16[uptr + column]);
+            }
+        }
+
+        private static int DCTColumn16Wbits(float[] linein, int[] lineout, int column, int wbits, int maxwbits)
+        {
+            // input columns are in fact stored in lines now
+
+            bool dowbits = wbits != maxwbits;
+            int wbitsMaxValue = 1 << wbits;
+
+            float total = 0.0f;
+            //            const float oosob = 2.0f / Constants.TerrainPatchSize;
+            int inlinesptr = Constants.TerrainPatchSize*column;
+
+            for (int n = 0; n < Constants.TerrainPatchSize; n++)
+            {
+                total += linein[inlinesptr + n];
+            }
+
+            //            lineout[CopyMatrix16[column]] = (int)(OO_SQRT2 * total * oosob * QuantizeTable16[column]);
+            int tmp = (int) (OO_SQRT2*total*QuantizeTable16[column]);
+            lineout[CopyMatrix16[column]] = tmp;
+
+            if (dowbits)
+            {
+                if (tmp < 0) tmp *= -1;
+                while (tmp > wbitsMaxValue)
+                {
+                    wbits++;
+                    wbitsMaxValue = 1 << wbits;
+                    if (wbits == maxwbits)
+                    {
+                        dowbits = false;
+                        break;
+                    }
+                }
+            }
+
+            for (int uptr = Constants.TerrainPatchSize;
+                 uptr < Constants.TerrainPatchSize*Constants.TerrainPatchSize;
+                 uptr += Constants.TerrainPatchSize)
+            {
+                total = 0.0f;
+
+                for (int n = inlinesptr, ptru = uptr; n < inlinesptr + Constants.TerrainPatchSize; n++, ptru++)
+                {
+                    total += linein[n]*CosineTable16[ptru];
+                }
+
+                tmp = (int) (total*QuantizeTable16[uptr + column]);
+                lineout[CopyMatrix16[uptr + column]] = tmp;
+
+                if (dowbits)
+                {
+                    if (tmp < 0) tmp *= -1;
+                    while (tmp > wbitsMaxValue)
+                    {
+                        wbits++;
+                        wbitsMaxValue = 1 << wbits;
+                        if (wbits == maxwbits)
+                        {
+                            dowbits = false;
+                            break;
+                        }
+                    }
+                }
+            }
+            return wbits;
+        }
+
+        public static void DecodePatch(int[] patches, BitPack bitpack, TerrainPatch.Header header, int size)
+        {
+            for (int n = 0; n < size*size; n++)
+            {
+                // ?
+                int temp = bitpack.UnpackBits(1);
+                if (temp != 0)
+                {
+                    // Value or EOB
+                    temp = bitpack.UnpackBits(1);
+                    if (temp != 0)
+                    {
+                        // Value
+                        temp = bitpack.UnpackBits(1);
+                        if (temp != 0)
+                        {
+                            // Negative
+                            temp = bitpack.UnpackBits((int) header.WordBits);
+                            patches[n] = temp*-1;
+                        }
+                        else
+                        {
+                            // Positive
+                            temp = bitpack.UnpackBits((int) header.WordBits);
+                            patches[n] = temp;
+                        }
+                    }
+                    else
+                    {
+                        // Set the rest to zero
+                        // TODO: This might not be necessary
+                        for (int o = n; o < size*size; o++)
+                        {
+                            patches[o] = 0;
+                        }
+                        break;
+                    }
+                }
+                else
+                {
+                    patches[n] = 0;
+                }
+            }
+        }
+
+        private static void EncodePatch(BitPack output, int[] patch, int postquant, int wbits)
+        {
+            int maxwbitssize = (1 << wbits) - 1;
+
+            if (postquant > Constants.TerrainPatchSize*Constants.TerrainPatchSize || postquant < 0)
+            {
+                Logger.Log("Postquant is outside the range of allowed values in EncodePatch()", Helpers.LogLevel.Error);
+                return;
+            }
+
+            if (postquant != 0) patch[Constants.TerrainPatchSize*Constants.TerrainPatchSize - postquant] = 0;
+
+            for (int i = 0; i < Constants.TerrainPatchSize*Constants.TerrainPatchSize; i++)
+            {
+                int temp = patch[i];
+
+                if (temp == 0)
+                {
+                    bool eob = true;
+
+                    for (int j = i; j < Constants.TerrainPatchSize*Constants.TerrainPatchSize - postquant; j++)
+                    {
+                        if (patch[j] != 0)
+                        {
+                            eob = false;
+                            break;
+                        }
+                    }
+
+                    if (eob)
+                    {
+                        output.PackBits(ZERO_EOB, 2);
+                        return;
+                    }
+                    output.PackBits(ZERO_CODE, 1);
+                }
+                else
+                {
+                    if (temp < 0)
+                    {
+                        temp *= -1;
+
+                        if (temp > maxwbitssize) temp = maxwbitssize;
+
+                        output.PackBits(NEGATIVE_VALUE, 3);
+                        output.PackBits(temp, wbits);
+                    }
+                    else
+                    {
+                        if (temp > maxwbitssize) temp = maxwbitssize;
+
+                        output.PackBits(POSITIVE_VALUE, 3);
+                        output.PackBits(temp, wbits);
+                    }
+                }
+            }
+        }
+
+        public static float[] DecompressPatch(int[] patches, TerrainPatch.Header header, TerrainPatch.GroupHeader group)
+        {
+            float[] block = new float[group.PatchSize*group.PatchSize];
+            float[] output = new float[group.PatchSize*group.PatchSize];
+            int prequant = (header.QuantWBits >> 4) + 2;
+            int quantize = 1 << prequant;
+            float ooq = 1.0f/quantize;
+            float mult = ooq*header.Range;
+            float addval = mult*(1 << (prequant - 1)) + header.DCOffset;
+
+            if (group.PatchSize == Constants.TerrainPatchSize)
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize*Constants.TerrainPatchSize; n++)
+                {
+                    block[n] = patches[CopyMatrix16[n]]*DequantizeTable16[n];
+                }
+
+                float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+                for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                    IDCTColumn16(block, ftemp, o);
+                for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                    IDCTLine16(ftemp, block, o);
+            }
+            else
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize*2*Constants.TerrainPatchSize*2; n++)
+                {
+                    block[n] = patches[CopyMatrix32[n]]*DequantizeTable32[n];
+                }
+
+                Logger.Log("Implement IDCTPatchLarge", Helpers.LogLevel.Error);
+            }
+
+            for (int j = 0; j < block.Length; j++)
+            {
+                output[j] = block[j]*mult + addval;
+            }
+
+            return output;
+        }
+
+        private static int[] CompressPatch(float[] patchData, TerrainPatch.Header header, int prequant, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int wordsize = (prequant - 2) & 0x0f;
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+
+            header.QuantWBits = wordsize;
+            header.QuantWBits |= wordsize << 4;
+
+            int k = 0;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                    block[k++] = patchData[j*Constants.TerrainPatchSize + i]*premult - sub;
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        private static int[] CompressPatch(float[,] patchData, TerrainPatch.Header header, int prequant, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+            int wordsize = (prequant - 2) & 0x0f;
+
+            header.QuantWBits = wordsize;
+            header.QuantWBits |= wordsize << 4;
+
+            int k = 0;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                    block[k++] = patchData[j, i]*premult - sub;
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        private static int[] CompressPatch(TerrainData terrData, int patchX, int patchY, TerrainPatch.Header header,
+                                                               int prequant, out int wbits)
+        {
+            float[] block = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int wordsize = prequant;
+            float oozrange = 1.0f/header.Range;
+            float range = (1 << prequant);
+            float premult = oozrange*range;
+            float sub = (1 << (prequant - 1)) + header.DCOffset*premult;
+
+            header.QuantWBits = wordsize - 2;
+            header.QuantWBits |= (prequant - 2) << 4;
+
+            int k = 0;
+
+            int jPatchLimit = patchY;
+            if (patchY >= (terrData.SizeY / Constants.TerrainPatchSize))
+            {
+                jPatchLimit = (int)(terrData.SizeY - Constants.TerrainPatchSize) / Constants.TerrainPatchSize;
+            }
+            jPatchLimit = (jPatchLimit + 1) * Constants.TerrainPatchSize;
+
+            int iPatchLimit = patchX;
+            if (patchX >= (terrData.SizeX / Constants.TerrainPatchSize))
+            {
+                iPatchLimit = (int)(terrData.SizeX - Constants.TerrainPatchSize) / Constants.TerrainPatchSize;
+            }
+            iPatchLimit = (iPatchLimit + 1) * Constants.TerrainPatchSize;
+
+            for (int j = patchY * Constants.TerrainPatchSize; j < jPatchLimit; j++)
+            {
+                for (int i = patchX * Constants.TerrainPatchSize; i < iPatchLimit; i++)
+                {
+                    // block[k++] = (heightmap[j*pRegionSizeX + i])*premult - sub;
+                    block[k++] = terrData[j, i] - sub;
+                }
+            }
+
+            float[] ftemp = new float[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+            int[] itemp = new int[Constants.TerrainPatchSize*Constants.TerrainPatchSize];
+
+            int maxWbits = prequant + 5;
+            wbits = (prequant >> 1);
+
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                DCTLine16(block, ftemp, o);
+            for (int o = 0; o < Constants.TerrainPatchSize; o++)
+                wbits = DCTColumn16Wbits(ftemp, itemp, o, wbits, maxWbits);
+
+            return itemp;
+        }
+
+        #region Initialization
+
+        private static void BuildDequantizeTable16()
+        {
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                {
+                    DequantizeTable16[j*Constants.TerrainPatchSize + i] = 1.0f + 2.0f*(i + j);
+                }
+            }
+        }
+
+        private static void BuildQuantizeTable16()
+        {
+            const float oosob = 2.0f/Constants.TerrainPatchSize;
+            for (int j = 0; j < Constants.TerrainPatchSize; j++)
+            {
+                for (int i = 0; i < Constants.TerrainPatchSize; i++)
+                {
+//                    QuantizeTable16[j * Constants.TerrainPatchSize + i] = 1.0f / (1.0f + 2.0f * ((float)i + (float)j));
+                    QuantizeTable16[j*Constants.TerrainPatchSize + i] = oosob/(1.0f + 2.0f*(i + (float) j));
+                }
+            }
+        }
+
+        private static void SetupCosines16()
+        {
+            const float hposz = (float) Math.PI*0.5f/Constants.TerrainPatchSize;
+
+            for (int u = 0; u < Constants.TerrainPatchSize; u++)
+            {
+                for (int n = 0; n < Constants.TerrainPatchSize; n++)
+                {
+                    CosineTable16[u*Constants.TerrainPatchSize + n] = (float) Math.Cos((2.0f*n + 1.0f)*u*hposz);
+                }
+            }
+        }
+
+        private static void BuildCopyMatrix16()
+        {
+            bool diag = false;
+            bool right = true;
+            int i = 0;
+            int j = 0;
+            int count = 0;
+
+            while (i < Constants.TerrainPatchSize && j < Constants.TerrainPatchSize)
+            {
+                CopyMatrix16[j*Constants.TerrainPatchSize + i] = count++;
+
+                if (!diag)
+                {
+                    if (right)
+                    {
+                        if (i < Constants.TerrainPatchSize - 1) i++;
+                        else j++;
+
+                        right = false;
+                        diag = true;
+                    }
+                    else
+                    {
+                        if (j < Constants.TerrainPatchSize - 1) j++;
+                        else i++;
+
+                        right = true;
+                        diag = true;
+                    }
+                }
+                else
+                {
+                    if (right)
+                    {
+                        i++;
+                        j--;
+                        if (i == Constants.TerrainPatchSize - 1 || j == 0) diag = false;
+                    }
+                    else
+                    {
+                        i--;
+                        j++;
+                        if (j == Constants.TerrainPatchSize - 1 || i == 0) diag = false;
+                    }
+                }
+            }
+        }
+
+        #endregion Initialization
+    }
+}
\ No newline at end of file