3 files changed, 593 insertions, 42 deletions

diff --git a/OpenSim/Framework/Constants.cs b/OpenSim/Framework/Constants.cs
index a2eb5ee..d18b32e 100644
--- a/OpenSim/Framework/Constants.cs
+++ b/OpenSim/Framework/Constants.cs
@@ -30,9 +30,16 @@ namespace OpenSim.Framework
 {
     public class Constants
     {
+        // 'RegionSize' captures the legacy region size.
+        // DO NOT USE THIS FOR ANY NEW CODE. Use Scene.RegionSize[XYZ] as a region might not
+        //      be the legacy region size.
         public const uint RegionSize = 256;
         public const uint RegionHeight = 4096;
-        public const byte TerrainPatchSize = 16;
+
+        // Since terrain is stored in 16x16 heights, regions must be a multiple of this number and that is the minimum
+        public const int MinRegionSize = 16;
+        public const int TerrainPatchSize = 16;
+
         public const string DefaultTexture = "89556747-24cb-43ed-920b-47caed15465f";
 
         public enum EstateAccessCodex : uint
diff --git a/OpenSim/Framework/RegionInfo.cs b/OpenSim/Framework/RegionInfo.cs
index 24b9c89..cf909cd 100644
--- a/OpenSim/Framework/RegionInfo.cs
+++ b/OpenSim/Framework/RegionInfo.cs
@@ -99,6 +99,7 @@ namespace OpenSim.Framework
     public class RegionInfo
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private static readonly string LogHeader = "[REGION INFO]";
 
         public bool commFailTF = false;
         public ConfigurationMember configMember;
@@ -137,16 +138,20 @@ namespace OpenSim.Framework
         public bool m_allow_alternate_ports;
         protected string m_externalHostName;
         protected IPEndPoint m_internalEndPoint;
-        protected uint? m_regionLocX;
-        protected uint? m_regionLocY;
         protected uint m_remotingPort;
         public UUID RegionID = UUID.Zero;
         public string RemotingAddress;
         public UUID ScopeID = UUID.Zero;
         private UUID m_maptileStaticUUID = UUID.Zero;
 
-        private Dictionary<String, String> m_otherSettings = new Dictionary<string, string>();
+        public uint RegionWorldLocX = 0;
+        public uint RegionWorldLocY = 0;
+        public uint RegionWorldLocZ = 0;
+        public uint RegionSizeX = Constants.RegionSize;
+        public uint RegionSizeY = Constants.RegionSize;
+        public uint RegionSizeZ = Constants.RegionHeight;
 
+        private Dictionary<String, String> m_otherSettings = new Dictionary<string, string>();
 
         // Apparently, we're applying the same estatesettings regardless of whether it's local or remote.
 
@@ -229,11 +234,8 @@ namespace OpenSim.Framework
             m_serverURI = string.Empty;
         }
 
-        public RegionInfo(uint regionLocX, uint regionLocY, IPEndPoint internalEndPoint, string externalUri)
+        public RegionInfo(uint legacyRegionLocX, uint legacyRegionLocY, IPEndPoint internalEndPoint, string externalUri)
         {
-            m_regionLocX = regionLocX;
-            m_regionLocY = regionLocY;
-
             m_internalEndPoint = internalEndPoint;
             m_externalHostName = externalUri;
             m_serverURI = string.Empty;
@@ -447,25 +449,66 @@ namespace OpenSim.Framework
 
         /// <summary>
         /// The x co-ordinate of this region in map tiles (e.g. 1000).
+        /// Coordinate is scaled as world coordinates divided by the legacy region size
+        /// and is thus is the number of legacy regions.
+        /// </summary>
+        public uint LegacyRegionLocX
+        {
+            get { return RegionWorldLocX / Constants.RegionSize; }
+            set { RegionWorldLocX = value * Constants.RegionSize; }
+        }
+
+        /// <summary>
+        /// The y co-ordinate of this region in map tiles (e.g. 1000).
+        /// Coordinate is scaled as world coordinates divided by the legacy region size
+        /// and is thus is the number of legacy regions.
+        /// </summary>
+        public uint LegacyRegionLocY
+        {
+            get { return RegionWorldLocY / Constants.RegionSize; }
+            set { RegionWorldLocY = value * Constants.RegionSize; }
+        }
+
+        /// <summary>
+        /// The x co-ordinate of this region in map tiles (e.g. 1000).
+        /// Coordinate is scaled as world coordinates divided by the legacy region size
+        /// and is thus is the number of legacy regions.
+        /// DO NOT USE FOR NEW CODE! This entrypoint exists for downward compatability with external modules.
         /// </summary>
         public uint RegionLocX
         {
-            get { return m_regionLocX.Value; }
-            set { m_regionLocX = value; }
+            get { return LegacyRegionLocX; }
+            set { LegacyRegionLocX = value; }
         }
 
         /// <summary>
         /// The y co-ordinate of this region in map tiles (e.g. 1000).
+        /// Coordinate is scaled as world coordinates divided by the legacy region size
+        /// and is thus is the number of legacy regions.
+        /// DO NOT USE FOR NEW CODE! This entrypoint exists for downward compatability with external modules.
         /// </summary>
         public uint RegionLocY
         {
-            get { return m_regionLocY.Value; }
-            set { m_regionLocY = value; }
+            get { return LegacyRegionLocY; }
+            set { LegacyRegionLocY = value; }
+        }
+
+        public void SetDefaultRegionSize()
+        {
+            RegionWorldLocX = 0;
+            RegionWorldLocY = 0;
+            RegionWorldLocZ = 0;
+            RegionSizeX = Constants.RegionSize;
+            RegionSizeY = Constants.RegionSize;
+            RegionSizeZ = Constants.RegionHeight;
         }
 
+        // A unique region handle is created from the region's world coordinates.
+        // This cannot be changed because some code expects to receive the region handle and then
+        //    compute the region coordinates from it.
         public ulong RegionHandle
         {
-            get { return Util.UIntsToLong((RegionLocX * (uint) Constants.RegionSize), (RegionLocY * (uint) Constants.RegionSize)); }
+            get { return Util.UIntsToLong(RegionWorldLocX, RegionWorldLocY); }
         }
 
         public void SetEndPoint(string ipaddr, int port)
@@ -572,8 +615,25 @@ namespace OpenSim.Framework
 
             string[] locationElements = location.Split(new char[] {','});
 
-            m_regionLocX = Convert.ToUInt32(locationElements[0]);
-            m_regionLocY = Convert.ToUInt32(locationElements[1]);
+            LegacyRegionLocX = Convert.ToUInt32(locationElements[0]);
+            LegacyRegionLocY = Convert.ToUInt32(locationElements[1]);
+
+            // Region size
+            // Default to legacy region size if not specified.
+            allKeys.Remove("SizeX");
+            string configSizeX = config.GetString("SizeX", Constants.RegionSize.ToString());
+            config.Set("SizeX", configSizeX);
+            RegionSizeX = Convert.ToUInt32(configSizeX);
+            allKeys.Remove("SizeY");
+            string configSizeY = config.GetString("SizeY", Constants.RegionSize.ToString());
+            config.Set("SizeY", configSizeX);
+            RegionSizeY = Convert.ToUInt32(configSizeY);
+            allKeys.Remove("SizeZ");
+            string configSizeZ = config.GetString("SizeZ", Constants.RegionHeight.ToString());
+            config.Set("SizeZ", configSizeX);
+            RegionSizeZ = Convert.ToUInt32(configSizeZ);
+
+            DoRegionSizeSanityChecks();
 
             // InternalAddress
             //
@@ -693,6 +753,48 @@ namespace OpenSim.Framework
             }
         }
 
+        // Make sure user specified region sizes are sane.
+        // Must be multiples of legacy region size (256).
+        private void DoRegionSizeSanityChecks()
+        {
+            if (RegionSizeX != Constants.RegionSize || RegionSizeY != Constants.RegionSize)
+            {
+                // Doing non-legacy region sizes.
+                // Enforce region size to be multiples of the legacy region size (256)
+                uint partial = RegionSizeX % Constants.RegionSize;
+                if (partial != 0)
+                {
+                    RegionSizeX -= partial;
+                    if (RegionSizeX == 0)
+                        RegionSizeX = Constants.RegionSize;
+                    m_log.ErrorFormat("{0} Region size must be multiple of {1}. Enforcing {2}.RegionSizeX={3} instead of specified {4}",
+                        LogHeader, Constants.RegionSize, m_regionName, RegionSizeX, RegionSizeX + partial);
+                }
+                partial = RegionSizeY % Constants.RegionSize;
+                if (partial != 0)
+                {
+                    RegionSizeY -= partial;
+                    if (RegionSizeY == 0)
+                        RegionSizeY = Constants.RegionSize;
+                    m_log.ErrorFormat("{0} Region size must be multiple of {1}. Enforcing {2}.RegionSizeY={3} instead of specified {4}",
+                        LogHeader, Constants.RegionSize, m_regionName, RegionSizeY, RegionSizeY + partial);
+                }
+
+                // Because of things in the viewer, regions MUST be square.
+                // Remove this check when viewers have been updated.
+                if (RegionSizeX != RegionSizeY)
+                {
+                    uint minSize = Math.Min(RegionSizeX, RegionSizeY);
+                    RegionSizeX = minSize;
+                    RegionSizeY = minSize;
+                    m_log.ErrorFormat("{0} Regions must be square until viewers are updated. Forcing region {1} size to <{2},{3}>",
+                                                    LogHeader, m_regionName, RegionSizeX, RegionSizeY);
+                }
+
+                m_log.InfoFormat("{0} Region {1} size set to <{2},{3}>", LogHeader, m_regionName, RegionSizeX, RegionSizeY);
+            }
+        }
+
         private void WriteNiniConfig(IConfigSource source)
         {
             IConfig config = source.Configs[RegionName];
@@ -704,9 +806,16 @@ namespace OpenSim.Framework
 
             config.Set("RegionUUID", RegionID.ToString());
 
-            string location = String.Format("{0},{1}", m_regionLocX, m_regionLocY);
+            string location = String.Format("{0},{1}", LegacyRegionLocX, LegacyRegionLocY);
             config.Set("Location", location);
 
+            if (RegionSizeX != Constants.RegionSize || RegionSizeY != Constants.RegionSize)
+            {
+                config.Set("SizeX", RegionSizeX);
+                config.Set("SizeY", RegionSizeY);
+                config.Set("SizeZ", RegionSizeZ);
+            }
+
             config.Set("InternalAddress", m_internalEndPoint.Address.ToString());
             config.Set("InternalPort", m_internalEndPoint.Port);
 
@@ -789,10 +898,18 @@ namespace OpenSim.Framework
                                                 RegionID.ToString(), true);
             configMember.addConfigurationOption("sim_name", ConfigurationOption.ConfigurationTypes.TYPE_STRING_NOT_EMPTY,
                                                 "Region Name", RegionName, true);
+
             configMember.addConfigurationOption("sim_location_x", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
-                                                "Grid Location (X Axis)", m_regionLocX.ToString(), true);
+                                                "Grid Location (X Axis)", LegacyRegionLocX.ToString(), true);
             configMember.addConfigurationOption("sim_location_y", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
-                                                "Grid Location (Y Axis)", m_regionLocY.ToString(), true);
+                                                "Grid Location (Y Axis)", LegacyRegionLocY.ToString(), true);
+            configMember.addConfigurationOption("sim_size_x", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in X dimension", RegionSizeX.ToString(), true);
+            configMember.addConfigurationOption("sim_size_y", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in Y dimension", RegionSizeY.ToString(), true);
+            configMember.addConfigurationOption("sim_size_z", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in Z dimension", RegionSizeZ.ToString(), true);
+
             //m_configMember.addConfigurationOption("datastore", ConfigurationOption.ConfigurationTypes.TYPE_STRING_NOT_EMPTY, "Filename for local storage", "OpenSim.db", false);
             configMember.addConfigurationOption("internal_ip_address",
                                                 ConfigurationOption.ConfigurationTypes.TYPE_IP_ADDRESS,
@@ -855,10 +972,18 @@ namespace OpenSim.Framework
                                                 UUID.Random().ToString(), true);
             configMember.addConfigurationOption("sim_name", ConfigurationOption.ConfigurationTypes.TYPE_STRING_NOT_EMPTY,
                                                 "Region Name", "OpenSim Test", false);
+
             configMember.addConfigurationOption("sim_location_x", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
                                                 "Grid Location (X Axis)", "1000", false);
             configMember.addConfigurationOption("sim_location_y", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
                                                 "Grid Location (Y Axis)", "1000", false);
+            configMember.addConfigurationOption("sim_size_x", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in X dimension", Constants.RegionSize.ToString(), false);
+            configMember.addConfigurationOption("sim_size_y", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in Y dimension", Constants.RegionSize.ToString(), false);
+            configMember.addConfigurationOption("sim_size_z", ConfigurationOption.ConfigurationTypes.TYPE_UINT32,
+                                                "Size of region in Z dimension", Constants.RegionHeight.ToString(), false);
+
             //m_configMember.addConfigurationOption("datastore", ConfigurationOption.ConfigurationTypes.TYPE_STRING_NOT_EMPTY, "Filename for local storage", "OpenSim.db", false);
             configMember.addConfigurationOption("internal_ip_address",
                                                 ConfigurationOption.ConfigurationTypes.TYPE_IP_ADDRESS,
@@ -916,10 +1041,19 @@ namespace OpenSim.Framework
                     RegionName = (string) configuration_result;
                     break;
                 case "sim_location_x":
-                    m_regionLocX = (uint) configuration_result;
+                    LegacyRegionLocX = (uint) configuration_result;
                     break;
                 case "sim_location_y":
-                    m_regionLocY = (uint) configuration_result;
+                    LegacyRegionLocY = (uint) configuration_result;
+                    break;
+                case "sim_size_x":
+                    RegionSizeX = (uint) configuration_result;
+                    break;
+                case "sim_size_y":
+                    RegionSizeY = (uint) configuration_result;
+                    break;
+                case "sim_size_z":
+                    RegionSizeZ = (uint) configuration_result;
                     break;
                 case "internal_ip_address":
                     IPAddress address = (IPAddress) configuration_result;
@@ -1000,8 +1134,13 @@ namespace OpenSim.Framework
             args["external_host_name"] = OSD.FromString(ExternalHostName);
             args["http_port"] = OSD.FromString(HttpPort.ToString());
             args["server_uri"] = OSD.FromString(ServerURI);
-            args["region_xloc"] = OSD.FromString(RegionLocX.ToString());
-            args["region_yloc"] = OSD.FromString(RegionLocY.ToString());
+
+            args["region_xloc"] = OSD.FromString(LegacyRegionLocX.ToString());
+            args["region_yloc"] = OSD.FromString(LegacyRegionLocY.ToString());
+            args["region_size_x"] = OSD.FromString(RegionSizeX.ToString());
+            args["region_size_y"] = OSD.FromString(RegionSizeY.ToString());
+            args["region_size_z"] = OSD.FromString(RegionSizeZ.ToString());
+
             args["internal_ep_address"] = OSD.FromString(InternalEndPoint.Address.ToString());
             args["internal_ep_port"] = OSD.FromString(InternalEndPoint.Port.ToString());
             if ((RemotingAddress != null) && !RemotingAddress.Equals(""))
@@ -1032,14 +1171,21 @@ namespace OpenSim.Framework
             {
                 uint locx;
                 UInt32.TryParse(args["region_xloc"].AsString(), out locx);
-                RegionLocX = locx;
+                LegacyRegionLocX = locx;
             }
             if (args["region_yloc"] != null)
             {
                 uint locy;
                 UInt32.TryParse(args["region_yloc"].AsString(), out locy);
-                RegionLocY = locy;
+                LegacyRegionLocY = locy;
             }
+            if (args.ContainsKey("region_size_x"))
+                RegionSizeX = (uint)args["region_size_x"].AsInteger();
+            if (args.ContainsKey("region_size_y"))
+                RegionSizeY = (uint)args["region_size_y"].AsInteger();
+            if (args.ContainsKey("region_size_z"))
+                RegionSizeZ = (uint)args["region_size_z"].AsInteger();
+
             IPAddress ip_addr = null;
             if (args["internal_ep_address"] != null)
             {
@@ -1076,23 +1222,5 @@ namespace OpenSim.Framework
             regionInfo.ServerURI = serverURI;
             return regionInfo;
         }
-
-        public Dictionary<string, object> ToKeyValuePairs()
-        {
-            Dictionary<string, object> kvp = new Dictionary<string, object>();
-            kvp["uuid"] = RegionID.ToString();
-            kvp["locX"] = RegionLocX.ToString();
-            kvp["locY"] = RegionLocY.ToString();
-            kvp["external_ip_address"] = ExternalEndPoint.Address.ToString();
-            kvp["external_port"] = ExternalEndPoint.Port.ToString();
-            kvp["external_host_name"] = ExternalHostName;
-            kvp["http_port"] = HttpPort.ToString();
-            kvp["internal_ip_address"] = InternalEndPoint.Address.ToString();
-            kvp["internal_port"] = InternalEndPoint.Port.ToString();
-            kvp["alternate_ports"] = m_allow_alternate_ports.ToString();
-            kvp["server_uri"] = ServerURI;
-
-            return kvp;
-        }
     }
 }
diff --git a/OpenSim/Framework/TerrainData.cs b/OpenSim/Framework/TerrainData.cs
new file mode 100644
index 0000000..d5dad8f
--- /dev/null
+++ b/OpenSim/Framework/TerrainData.cs
@@ -0,0 +1,416 @@
+/*
+ * 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.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Reflection;
+
+using OpenMetaverse;
+
+using log4net;
+
+namespace OpenSim.Framework
+{
+    public abstract class TerrainData
+    {
+        // Terrain always is a square
+        public int SizeX { get; protected set; }
+        public int SizeY { get; protected set; }
+        public int SizeZ { get; protected set; }
+
+        // A height used when the user doesn't specify anything
+        public const float DefaultTerrainHeight = 21f;
+
+        public abstract float this[int x, int y] { get; set; }
+        // Someday terrain will have caves
+        public abstract float this[int x, int y, int z] { get; set; }
+
+        public bool IsTainted { get; protected set; }
+        public abstract bool IsTaintedAt(int xx, int yy);
+        public abstract void ClearTaint();
+
+        public abstract void ClearLand();
+        public abstract void ClearLand(float height);
+
+        // Return a representation of this terrain for storing as a blob in the database.
+        // Returns 'true' to say blob was stored in the 'out' locations.
+        public abstract bool GetDatabaseBlob(out int DBFormatRevisionCode, out Array blob);
+
+        // Given a revision code and a blob from the database, create and return the right type of TerrainData.
+        // The sizes passed are the expected size of the region. The database info will be used to
+        //     initialize the heightmap of that sized region with as much data is in the blob.
+        // Return created TerrainData or 'null' if unsuccessful.
+        public static TerrainData CreateFromDatabaseBlobFactory(int pSizeX, int pSizeY, int pSizeZ, int pFormatCode, byte[] pBlob)
+        {
+            // For the moment, there is only one implementation class
+            return new HeightmapTerrainData(pSizeX, pSizeY, pSizeZ, pFormatCode, pBlob);
+        }
+
+        // return a special compressed representation of the heightmap in shorts
+        public abstract short[] GetCompressedMap();
+        public abstract float CompressionFactor { get; }
+
+        public abstract double[,] GetDoubles();
+        public abstract TerrainData Clone();
+    }
+
+    // The terrain is stored in the database as a blob with a 'revision' field.
+    // Some implementations of terrain storage would fill the revision field with
+    //    the time the terrain was stored. When real revisions were added and this
+    //    feature removed, that left some old entries with the time in the revision
+    //    field.
+    // Thus, if revision is greater than 'RevisionHigh' then terrain db entry is
+    //    left over and it is presumed to be 'Legacy256'.
+    // Numbers are arbitrary and are chosen to to reduce possible mis-interpretation.
+    // If a revision does not match any of these, it is assumed to be Legacy256.
+    public enum DBTerrainRevision
+    {
+        // Terrain is 'double[256,256]'
+        Legacy256 = 11,
+        // Terrain is 'int32, int32, float[,]' where the ints are X and Y dimensions
+        // The dimensions are presumed to be multiples of 16 and, more likely, multiples of 256.
+        Variable2D = 22,
+        // Terrain is 'int32, int32, int32, int16[]' where the ints are X and Y dimensions
+        //   and third int is the 'compression factor'. The heights are compressed as
+        //   "short compressedHeight = (short)(height * compressionFactor);"
+        // The dimensions are presumed to be multiples of 16 and, more likely, multiples of 256.
+        Compressed2D = 27,
+        // A revision that is not listed above or any revision greater than this value is 'Legacy256'.
+        RevisionHigh = 1234
+    }
+
+    // Version of terrain that is a heightmap.
+    // This should really be 'LLOptimizedHeightmapTerrainData' as it includes knowledge
+    //    of 'patches' which are 16x16 terrain areas which can be sent separately to the viewer.
+    // The heighmap is kept as an array of short integers. The integer values are converted to
+    //    and from floats by TerrainCompressionFactor. Shorts are used to limit storage used.
+    public class HeightmapTerrainData : TerrainData
+    {
+        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+        private static string LogHeader = "[TERRAIN DATA]";
+
+        // TerrainData.this[x, y]
+        public override float this[int x, int y]
+        {
+            get { return FromCompressedHeight(m_heightmap[x, y]); }
+            set {
+                short newVal = ToCompressedHeight(value);
+                if (m_heightmap[x, y] != newVal)
+                {
+                    m_heightmap[x, y] = newVal;
+                    m_taint[x / Constants.TerrainPatchSize, y / Constants.TerrainPatchSize] = true;
+                    // m_log.DebugFormat("{0} set[{1},{2}] to {3} ({4})", LogHeader, x, y, value, newVal);
+                }
+            }
+        }
+
+        // TerrainData.this[x, y, z]
+        public override float this[int x, int y, int z]
+        {
+            get { return this[x, y]; }
+            set { this[x, y] = value; }
+        }
+
+        // TerrainData.ClearTaint
+        public override void ClearTaint()
+        {
+            IsTainted = false;
+            for (int ii = 0; ii < m_taint.GetLength(0); ii++)
+                for (int jj = 0; jj < m_taint.GetLength(1); jj++)
+                    m_taint[ii, jj] = false;
+        }
+
+        // TerrainData.ClearLand
+        public override void ClearLand()
+        {
+            ClearLand(DefaultTerrainHeight);
+        }
+        // TerrainData.ClearLand(float)
+        public override void ClearLand(float pHeight)
+        {
+            short flatHeight = ToCompressedHeight(pHeight);
+            for (int xx = 0; xx < SizeX; xx++)
+                for (int yy = 0; yy < SizeY; yy++)
+                    m_heightmap[xx, yy] = flatHeight;
+        }
+
+        public override bool IsTaintedAt(int xx, int yy)
+        {
+            return m_taint[xx / Constants.TerrainPatchSize, yy / Constants.TerrainPatchSize];
+        }
+
+        // TerrainData.GetDatabaseBlob
+        // The user wants something to store in the database.
+        public override bool GetDatabaseBlob(out int DBRevisionCode, out Array blob)
+        {
+            bool ret = false;
+            if (SizeX == Constants.RegionSize && SizeY == Constants.RegionSize)
+            {
+                DBRevisionCode = (int)DBTerrainRevision.Legacy256;
+                blob = ToLegacyTerrainSerialization();
+                ret = true;
+            }
+            else
+            {
+                DBRevisionCode = (int)DBTerrainRevision.Compressed2D;
+                blob = ToCompressedTerrainSerialization();
+                ret = true;
+            }
+            return ret;
+        }
+
+        // TerrainData.CompressionFactor
+        private float m_compressionFactor = 100.0f;
+        public override float CompressionFactor { get { return m_compressionFactor; } }
+
+        // TerrainData.GetCompressedMap
+        public override short[] GetCompressedMap()
+        {
+            short[] newMap = new short[SizeX * SizeY];
+
+            int ind = 0;
+            for (int xx = 0; xx < SizeX; xx++)
+                for (int yy = 0; yy < SizeY; yy++)
+                    newMap[ind++] = m_heightmap[xx, yy];
+
+            return newMap;
+
+        }
+        // TerrainData.Clone
+        public override TerrainData Clone()
+        {
+            HeightmapTerrainData ret = new HeightmapTerrainData(SizeX, SizeY, SizeZ);
+            ret.m_heightmap = (short[,])this.m_heightmap.Clone();
+            return ret;
+        }
+
+        // TerrainData.GetDoubles
+        public override double[,] GetDoubles()
+        {
+            double[,] ret = new double[SizeX, SizeY];
+            for (int xx = 0; xx < SizeX; xx++)
+                for (int yy = 0; yy < SizeY; yy++)
+                    ret[xx, yy] = FromCompressedHeight(m_heightmap[xx, yy]);
+
+            return ret;
+        }
+
+
+        // =============================================================
+
+        private short[,] m_heightmap;
+        // Remember subregions of the heightmap that has changed.
+        private bool[,] m_taint;
+
+        // To save space (especially for large regions), keep the height as a short integer
+        //    that is coded as the float height times the compression factor (usually '100'
+        //    to make for two decimal points).
+        public short ToCompressedHeight(double pHeight)
+        {
+            return (short)(pHeight * CompressionFactor);
+        }
+
+        public float FromCompressedHeight(short pHeight)
+        {
+            return ((float)pHeight) / CompressionFactor;
+        }
+
+        // To keep with the legacy theme, create an instance of this class based on the
+        //     way terrain used to be passed around.
+        public HeightmapTerrainData(double[,] pTerrain)
+        {
+            SizeX = pTerrain.GetLength(0);
+            SizeY = pTerrain.GetLength(1);
+            SizeZ = (int)Constants.RegionHeight;
+            m_compressionFactor = 100.0f;
+
+            m_heightmap = new short[SizeX, SizeY];
+            for (int ii = 0; ii < SizeX; ii++)
+            {
+                for (int jj = 0; jj < SizeY; jj++)
+                {
+                    m_heightmap[ii, jj] = ToCompressedHeight(pTerrain[ii, jj]);
+
+                }
+            }
+
+            m_taint = new bool[SizeX / Constants.TerrainPatchSize, SizeY / Constants.TerrainPatchSize];
+            ClearTaint();
+        }
+
+        // Create underlying structures but don't initialize the heightmap assuming the caller will immediately do that
+        public HeightmapTerrainData(int pX, int pY, int pZ)
+        {
+            SizeX = pX;
+            SizeY = pY;
+            SizeZ = pZ;
+            m_compressionFactor = 100.0f;
+            m_heightmap = new short[SizeX, SizeY];
+            m_taint = new bool[SizeX / Constants.TerrainPatchSize, SizeY / Constants.TerrainPatchSize];
+            ClearTaint();
+        }
+
+        public HeightmapTerrainData(short[] cmap, float pCompressionFactor, int pX, int pY, int pZ) : this(pX, pY, pZ)
+        {
+            m_compressionFactor = pCompressionFactor;
+            int ind = 0;
+            for (int xx = 0; xx < SizeX; xx++)
+                for (int yy = 0; yy < SizeY; yy++)
+                    m_heightmap[xx, yy] = cmap[ind++];
+        }
+
+        // Create a heighmap from a database blob
+        public HeightmapTerrainData(int pSizeX, int pSizeY, int pSizeZ, int pFormatCode, byte[] pBlob) : this(pSizeX, pSizeY, pSizeZ)
+        {
+            switch ((DBTerrainRevision)pFormatCode)
+            {
+                case DBTerrainRevision.Compressed2D:
+                    FromCompressedTerrainSerialization(pBlob);
+                    m_log.DebugFormat("{0} HeightmapTerrainData create from Compressed2D serialization. Size=<{1},{2}>", LogHeader, SizeX, SizeY);
+                    break;
+                default:
+                    FromLegacyTerrainSerialization(pBlob);
+                    m_log.DebugFormat("{0} HeightmapTerrainData create from legacy serialization. Size=<{1},{2}>", LogHeader, SizeX, SizeY);
+                    break;
+            }
+        }
+
+        // Just create an array of doubles. Presumes the caller implicitly knows the size.
+        public Array ToLegacyTerrainSerialization()
+        {
+            Array ret = null;
+
+            using (MemoryStream str = new MemoryStream((int)Constants.RegionSize * (int)Constants.RegionSize * sizeof(double)))
+            {
+                using (BinaryWriter bw = new BinaryWriter(str))
+                {
+                    for (int xx = 0; xx < Constants.RegionSize; xx++)
+                    {
+                        for (int yy = 0; yy < Constants.RegionSize; yy++)
+                        {
+                            double height = this[xx, yy];
+                            if (height == 0.0)
+                                height = double.Epsilon;
+                            bw.Write(height);
+                        }
+                    }
+                }
+                ret = str.ToArray();
+            }
+            return ret;
+        }
+
+        // Just create an array of doubles. Presumes the caller implicitly knows the size.
+        public void FromLegacyTerrainSerialization(byte[] pBlob)
+        {
+            // In case database info doesn't match real terrain size, initialize the whole terrain.
+            ClearLand();
+
+            using (MemoryStream mstr = new MemoryStream(pBlob))
+            {
+                using (BinaryReader br = new BinaryReader(mstr))
+                {
+                    for (int xx = 0; xx < (int)Constants.RegionSize; xx++)
+                    {
+                        for (int yy = 0; yy < (int)Constants.RegionSize; yy++)
+                        {
+                            float val = (float)br.ReadDouble();
+                            if (xx < SizeX && yy < SizeY)
+                                m_heightmap[xx, yy] = ToCompressedHeight(val);
+                        }
+                    }
+                }
+                ClearTaint();
+            }
+        }
+        
+        // See the reader below.
+        public Array ToCompressedTerrainSerialization()
+        {
+            Array ret = null;
+            using (MemoryStream str = new MemoryStream((3 * sizeof(Int32)) + (SizeX * SizeY * sizeof(Int16))))
+            {
+                using (BinaryWriter bw = new BinaryWriter(str))
+                {
+                    bw.Write((Int32)DBTerrainRevision.Compressed2D);
+                    bw.Write((Int32)SizeX);
+                    bw.Write((Int32)SizeY);
+                    bw.Write((Int32)CompressionFactor);
+                    for (int yy = 0; yy < SizeY; yy++)
+                        for (int xx = 0; xx < SizeX; xx++)
+                        {
+                            bw.Write((Int16)m_heightmap[xx, yy]);
+                        }
+                }
+                ret = str.ToArray();
+            }
+            return ret;
+        }
+
+        // Initialize heightmap from blob consisting of:
+        //    int32, int32, int32, int32, int16[]
+        //    where the first int32 is format code, next two int32s are the X and y of heightmap data and
+        //    the forth int is the compression factor for the following int16s
+        // This is just sets heightmap info. The actual size of the region was set on this instance's
+        //    creation and any heights not initialized by theis blob are set to the default height.
+        public void FromCompressedTerrainSerialization(byte[] pBlob)
+        {
+            Int32 hmFormatCode, hmSizeX, hmSizeY, hmCompressionFactor;
+
+            using (MemoryStream mstr = new MemoryStream(pBlob))
+            {
+                using (BinaryReader br = new BinaryReader(mstr))
+                {
+                    hmFormatCode = br.ReadInt32();
+                    hmSizeX = br.ReadInt32();
+                    hmSizeY = br.ReadInt32();
+                    hmCompressionFactor = br.ReadInt32();
+
+                    m_compressionFactor = hmCompressionFactor;
+
+                    // In case database info doesn't match real terrain size, initialize the whole terrain.
+                    ClearLand();
+
+                    for (int yy = 0; yy < hmSizeY; yy++)
+                    {
+                        for (int xx = 0; xx < hmSizeX; xx++)
+                        {
+                            Int16 val = br.ReadInt16();
+                            if (xx < SizeX && yy < SizeY)
+                                m_heightmap[xx, yy] = val;
+                        }
+                    }
+                }
+                ClearTaint();
+
+                m_log.InfoFormat("{0} Read compressed 2d heightmap. Heightmap size=<{1},{2}>. Region size={<{3},{4}>. CompFact={5}", LogHeader,
+                                                        hmSizeX, hmSizeY, SizeX, SizeY, hmCompressionFactor);
+            }
+        }
+    }
+}