4 files changed, 183 insertions, 102 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
index e76d8a4..fa21233 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSCharacter.cs
@@ -39,8 +39,7 @@ public class BSCharacter : BSPhysObject
     private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
     private static readonly string LogHeader = "[BULLETS CHAR]";
 
-    private BSScene _scene;
-    public BSScene Scene { get { return _scene; } }
+    public BSScene Scene { get; private set; }
     private String _avName;
     // private bool _stopped;
     private Vector3 _size;
@@ -92,7 +91,7 @@ public class BSCharacter : BSPhysObject
     {
         _localID = localID;
         _avName = avName;
-        _scene = parent_scene;
+        Scene = parent_scene;
         _position = pos;
         _size = size;
         _flying = isFlying;
@@ -101,11 +100,11 @@ public class BSCharacter : BSPhysObject
         _buoyancy = ComputeBuoyancyFromFlying(isFlying);
         // The dimensions of the avatar capsule are kept in the scale.
         // Physics creates a unit capsule which is scaled by the physics engine.
-        _scale = new Vector3(_scene.Params.avatarCapsuleRadius, _scene.Params.avatarCapsuleRadius, size.Z);
-        _density = _scene.Params.avatarDensity;
+        _scale = new Vector3(Scene.Params.avatarCapsuleRadius, Scene.Params.avatarCapsuleRadius, size.Z);
+        _density = Scene.Params.avatarDensity;
         ComputeAvatarVolumeAndMass();   // set _avatarVolume and _mass based on capsule size, _density and _scale
 
-        Linkset = new BSLinkset(_scene, this);
+        Linkset = new BSLinkset(Scene, this);
 
         ShapeData shapeData = new ShapeData();
         shapeData.ID = _localID;
@@ -117,19 +116,19 @@ public class BSCharacter : BSPhysObject
         shapeData.Mass = _mass;
         shapeData.Buoyancy = _buoyancy;
         shapeData.Static = ShapeData.numericFalse;
-        shapeData.Friction = _scene.Params.avatarFriction;
-        shapeData.Restitution = _scene.Params.avatarRestitution;
+        shapeData.Friction = Scene.Params.avatarFriction;
+        shapeData.Restitution = Scene.Params.avatarRestitution;
 
         // do actual create at taint time
-        _scene.TaintedObject("BSCharacter.create", delegate()
+        Scene.TaintedObject("BSCharacter.create", delegate()
         {
             DetailLog("{0},BSCharacter.create", _localID);
-            BulletSimAPI.CreateObject(parent_scene.WorldID, shapeData);
+            BulletSimAPI.CreateObject(Scene.WorldID, shapeData);
 
             // Set the buoyancy for flying. This will be refactored when all the settings happen in C#
-            BulletSimAPI.SetObjectBuoyancy(_scene.WorldID, LocalID, _buoyancy);
+            BulletSimAPI.SetObjectBuoyancy(Scene.WorldID, LocalID, _buoyancy);
 
-            Body = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(_scene.World.Ptr, LocalID));
+            Body = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(Scene.World.Ptr, LocalID));
             // avatars get all collisions no matter what (makes walking on ground and such work)
             BulletSimAPI.AddToCollisionFlags2(Body.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
         });
@@ -141,9 +140,9 @@ public class BSCharacter : BSPhysObject
     public override void Destroy()
     {
         DetailLog("{0},BSCharacter.Destroy", LocalID);
-        _scene.TaintedObject("BSCharacter.destroy", delegate()
+        Scene.TaintedObject("BSCharacter.destroy", delegate()
         {
-            BulletSimAPI.DestroyObject(_scene.WorldID, _localID);
+            BulletSimAPI.DestroyObject(Scene.WorldID, _localID);
         });
     }
 
@@ -172,9 +171,9 @@ public class BSCharacter : BSPhysObject
 
             ComputeAvatarVolumeAndMass();
 
-            _scene.TaintedObject("BSCharacter.setSize", delegate()
+            Scene.TaintedObject("BSCharacter.setSize", delegate()
             {
-                BulletSimAPI.SetObjectScaleMass(_scene.WorldID, LocalID, _scale, _mass, true);
+                BulletSimAPI.SetObjectScaleMass(Scene.WorldID, LocalID, _scale, _mass, true);
             });
 
         } 
@@ -203,17 +202,17 @@ public class BSCharacter : BSPhysObject
 
     public override Vector3 Position { 
         get {
-            // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
+            // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, _localID);
             return _position; 
         } 
         set {
             _position = value;
             PositionSanityCheck();
 
-            _scene.TaintedObject("BSCharacter.setPosition", delegate()
+            Scene.TaintedObject("BSCharacter.setPosition", delegate()
             {
                 DetailLog("{0},BSCharacter.SetPosition,taint,pos={1},orient={2}", LocalID, _position, _orientation);
-                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                BulletSimAPI.SetObjectTranslation(Scene.WorldID, _localID, _position, _orientation);
             });
         } 
     }
@@ -229,10 +228,8 @@ public class BSCharacter : BSPhysObject
         float terrainHeight = Scene.TerrainManager.GetTerrainHeightAtXYZ(_position);
         if (Position.Z < terrainHeight)
         {
-            DetailLog("{0},BSCharacter.PositionAdjustUnderGround,call,pos={1},terrain={2}", LocalID, _position, terrainHeight);
-            Vector3 newPos = _position;
-            newPos.Z = terrainHeight + 2.0f;
-            _position = newPos;
+            DetailLog("{0},BSCharacter.PositionAdjustUnderGround,call,pos={1},terrain={2}", LocalID, _position, terrainHeight);

+            _position.Z = terrainHeight + 2.0f;
             ret = true;
         }
 
@@ -250,10 +247,10 @@ public class BSCharacter : BSPhysObject
         {
             // The new position value must be pushed into the physics engine but we can't
             //    just assign to "Position" because of potential call loops.
-            _scene.TaintedObject("BSCharacter.PositionSanityCheck", delegate()
+            Scene.TaintedObject("BSCharacter.PositionSanityCheck", delegate()
             {
                 DetailLog("{0},BSCharacter.PositionSanityCheck,taint,pos={1},orient={2}", LocalID, _position, _orientation);
-                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                BulletSimAPI.SetObjectTranslation(Scene.WorldID, _localID, _position, _orientation);
             });
             ret = true;
         }
@@ -301,10 +298,10 @@ public class BSCharacter : BSPhysObject
         set {
             _velocity = value;
             // m_log.DebugFormat("{0}: set velocity = {1}", LogHeader, _velocity);
-            _scene.TaintedObject("BSCharacter.setVelocity", delegate()
+            Scene.TaintedObject("BSCharacter.setVelocity", delegate()
             {
                 DetailLog("{0},BSCharacter.setVelocity,taint,vel={1}", LocalID, _velocity);
-                BulletSimAPI.SetObjectVelocity(_scene.WorldID, _localID, _velocity);
+                BulletSimAPI.SetObjectVelocity(Scene.WorldID, _localID, _velocity);
             });
         } 
     }
@@ -327,10 +324,10 @@ public class BSCharacter : BSPhysObject
         set {
             _orientation = value;
             // m_log.DebugFormat("{0}: set orientation to {1}", LogHeader, _orientation);
-            _scene.TaintedObject("BSCharacter.setOrientation", delegate()
+            Scene.TaintedObject("BSCharacter.setOrientation", delegate()
             {
-                // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
-                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, _localID);
+                BulletSimAPI.SetObjectTranslation(Scene.WorldID, _localID, _position, _orientation);
             });
         } 
     }
@@ -367,11 +364,11 @@ public class BSCharacter : BSPhysObject
         set { _throttleUpdates = value; } 
     }
     public override bool IsColliding {
-        get { return (_collidingStep == _scene.SimulationStep); } 
+        get { return (_collidingStep == Scene.SimulationStep); } 
         set { _isColliding = value; } 
     }
     public override bool CollidingGround {
-        get { return (_collidingGroundStep == _scene.SimulationStep); } 
+        get { return (_collidingGroundStep == Scene.SimulationStep); } 
         set { _collidingGround = value; } 
     }
     public override bool CollidingObj { 
@@ -393,10 +390,10 @@ public class BSCharacter : BSPhysObject
     public override float Buoyancy { 
         get { return _buoyancy; } 
         set { _buoyancy = value; 
-            _scene.TaintedObject("BSCharacter.setBuoyancy", delegate()
+            Scene.TaintedObject("BSCharacter.setBuoyancy", delegate()
             {
                 DetailLog("{0},BSCharacter.setBuoyancy,taint,buoy={1}", LocalID, _buoyancy);
-                BulletSimAPI.SetObjectBuoyancy(_scene.WorldID, LocalID, _buoyancy);
+                BulletSimAPI.SetObjectBuoyancy(Scene.WorldID, LocalID, _buoyancy);
             });
         } 
     }
@@ -440,7 +437,7 @@ public class BSCharacter : BSPhysObject
             _force.Y += force.Y;
             _force.Z += force.Z;
             // m_log.DebugFormat("{0}: AddForce. adding={1}, newForce={2}", LogHeader, force, _force);
-            _scene.TaintedObject("BSCharacter.AddForce", delegate()
+            Scene.TaintedObject("BSCharacter.AddForce", delegate()
             {
                 DetailLog("{0},BSCharacter.setAddForce,taint,addedForce={1}", LocalID, _force);
                 BulletSimAPI.AddObjectForce2(Body.Ptr, _force);
@@ -524,10 +521,9 @@ public class BSCharacter : BSPhysObject
         // Do some sanity checking for the avatar. Make sure it's above ground and inbounds.
         PositionSanityCheck2();
 
-        float heightHere = Scene.TerrainManager.GetTerrainHeightAtXYZ(_position);   // just for debug
+        float heightHere = Scene.TerrainManager.GetTerrainHeightAtXYZ(_position);   // only for debug
         DetailLog("{0},BSCharacter.UpdateProperties,call,pos={1},orient={2},vel={3},accel={4},rotVel={5},terrain={6}",
-                LocalID, entprop.Position, entprop.Rotation, entprop.Velocity, 
-                entprop.Acceleration, entprop.RotationalVelocity, heightHere);
+                LocalID, _position, _orientation, _velocity, _acceleration, _rotationalVelocity, heightHere);
     }
 
     // Called by the scene when a collision with this object is reported
@@ -539,16 +535,16 @@ public class BSCharacter : BSPhysObject
         // m_log.DebugFormat("{0}: Collide: ms={1}, id={2}, with={3}", LogHeader, _subscribedEventsMs, LocalID, collidingWith);
 
         // The following makes IsColliding() and IsCollidingGround() work
-        _collidingStep = _scene.SimulationStep;
+        _collidingStep = Scene.SimulationStep;
         if (collidingWith == BSScene.TERRAIN_ID || collidingWith == BSScene.GROUNDPLANE_ID)
         {
-            _collidingGroundStep = _scene.SimulationStep;
+            _collidingGroundStep = Scene.SimulationStep;
         }
         // DetailLog("{0},BSCharacter.Collison,call,with={1}", LocalID, collidingWith);
 
         // throttle collisions to the rate specified in the subscription
         if (_subscribedEventsMs != 0) {
-            int nowTime = _scene.SimulationNowTime;
+            int nowTime = Scene.SimulationNowTime;
             if (nowTime >= _nextCollisionOkTime) {
                 _nextCollisionOkTime = nowTime + _subscribedEventsMs;
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
index 7b4802e..2f55ba4 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSScene.cs
@@ -232,15 +232,15 @@ public class BSScene : PhysicsScene, IPhysicsParameters
         }
 
         // If Debug logging level, enable logging from the unmanaged code
+        m_DebugLogCallbackHandle = null;
         if (m_log.IsDebugEnabled || PhysicsLogging.Enabled)
         {
             m_log.DebugFormat("{0}: Initialize: Setting debug callback for unmanaged code", LogHeader);
             if (PhysicsLogging.Enabled)
+                // The handle is saved in a variable to make sure it doesn't get freed after this call
                 m_DebugLogCallbackHandle = new BulletSimAPI.DebugLogCallback(BulletLoggerPhysLog);
             else
                 m_DebugLogCallbackHandle = new BulletSimAPI.DebugLogCallback(BulletLogger);
-            // The handle is saved in a variable to make sure it doesn't get freed after this call
-            BulletSimAPI.SetDebugLogCallback(m_DebugLogCallbackHandle);
         }
 
         // Get the version of the DLL
@@ -257,7 +257,8 @@ public class BSScene : PhysicsScene, IPhysicsParameters
         // m_log.DebugFormat("{0}: Initialize: Calling BulletSimAPI.Initialize.", LogHeader);
         WorldID = BulletSimAPI.Initialize(worldExtent, m_paramsHandle.AddrOfPinnedObject(),
                                         m_maxCollisionsPerFrame, m_collisionArrayPinnedHandle.AddrOfPinnedObject(),
-                                        m_maxUpdatesPerFrame, m_updateArrayPinnedHandle.AddrOfPinnedObject());
+                                        m_maxUpdatesPerFrame, m_updateArrayPinnedHandle.AddrOfPinnedObject(),
+                                        m_DebugLogCallbackHandle);
 
         // Initialization to support the transition to a new API which puts most of the logic
         //   into the C# code so it is easier to modify and add to.
@@ -265,8 +266,6 @@ public class BSScene : PhysicsScene, IPhysicsParameters
 
         Constraints = new BSConstraintCollection(World);
 
-        // Note: choose one of the  two following lines
-        // BulletSimAPI.CreateInitialGroundPlaneAndTerrain(WorldID);
         TerrainManager = new BSTerrainManager(this);
         TerrainManager.CreateInitialGroundPlaneAndTerrain();
 
@@ -378,7 +377,9 @@ public class BSScene : PhysicsScene, IPhysicsParameters
         BSCharacter actor = new BSCharacter(localID, avName, this, position, size, isFlying);
         lock (PhysObjects) PhysObjects.Add(localID, actor);
 
-        // Remove kludge someday
+        // TODO: Remove kludge someday.
+        // We must generate a collision for avatars whether they collide or not.
+        // This is required by OpenSim to update avatar animations, etc.
         lock (m_avatarsWithCollisions) m_avatarsWithCollisions.Add(actor);
 
         return actor;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
index 28c1940..733d9c2 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs
@@ -44,8 +44,22 @@ public class BSTerrainManager
 {
     static string LogHeader = "[BULLETSIM TERRAIN MANAGER]";
 
+    // These height values are fractional so the odd values will be
+    //     noticable when debugging.
+    public const float HEIGHT_INITIALIZATION = 24.987f;
+    public const float HEIGHT_INITIAL_LASTHEIGHT = 24.876f;
+    public const float HEIGHT_GETHEIGHT_RET = 24.765f;
+
+    // If the min and max height are equal, we reduce the min by this
+    //    amount to make sure that a bounding box is built for the terrain.
+    public const float HEIGHT_EQUAL_FUDGE = 0.2f;
+
+    public const float TERRAIN_COLLISION_MARGIN = 0.2f;
+
+    // The scene that I am part of
     BSScene m_physicsScene;
 
+    // The ground plane created to keep thing from falling to infinity.
     private BulletBody m_groundPlane;
     
     // If doing mega-regions, if we're region zero we will be managing multiple
@@ -53,6 +67,10 @@ public class BSTerrainManager
     private Dictionary<Vector2, BulletBody> m_terrains;
     private Dictionary<Vector2, BulletHeightMapInfo> m_heightMaps;
 
+    // True of the terrain has been modified.
+    // Used to force recalculation of terrain height after terrain has been modified
+    private bool m_terrainModified;
+
     // If we are doing mega-regions, terrains are added from TERRAIN_ID to m_terrainCount.
     // This is incremented before assigning to new region so it is the last ID allocated.
     private uint m_terrainCount = BSScene.CHILDTERRAIN_ID - 1;
@@ -69,6 +87,7 @@ public class BSTerrainManager
         m_physicsScene = physicsScene;
         m_terrains = new Dictionary<Vector2,BulletBody>();
         m_heightMaps = new Dictionary<Vector2,BulletHeightMapInfo>();
+        m_terrainModified = false;
     }
 
     // Create the initial instance of terrain and the underlying ground plane.
@@ -80,17 +99,18 @@ public class BSTerrainManager
     public void CreateInitialGroundPlaneAndTerrain()
     {
         // The ground plane is here to catch things that are trying to drop to negative infinity
+        BulletShape groundPlaneShape = new BulletShape(BulletSimAPI.CreateGroundPlaneShape2(BSScene.GROUNDPLANE_ID, 1f, TERRAIN_COLLISION_MARGIN));
         m_groundPlane = new BulletBody(BSScene.GROUNDPLANE_ID, 
-                        BulletSimAPI.CreateGroundPlaneBody2(BSScene.GROUNDPLANE_ID, 1f, 0.4f));
+                        BulletSimAPI.CreateBodyWithDefaultMotionState2(groundPlaneShape.Ptr, Vector3.Zero, Quaternion.Identity));
         BulletSimAPI.AddObjectToWorld2(m_physicsScene.World.Ptr, m_groundPlane.Ptr);
 
-        Vector3 minTerrainCoords = new Vector3(0f, 0f, 24f);
-        Vector3 maxTerrainCoords = new Vector3(Constants.RegionSize, Constants.RegionSize, 25f);
+        Vector3 minTerrainCoords = new Vector3(0f, 0f, HEIGHT_INITIALIZATION - HEIGHT_EQUAL_FUDGE);
+        Vector3 maxTerrainCoords = new Vector3(Constants.RegionSize, Constants.RegionSize, HEIGHT_INITIALIZATION);
         int totalHeights = (int)maxTerrainCoords.X * (int)maxTerrainCoords.Y;
         float[] initialMap = new float[totalHeights];
         for (int ii = 0; ii < totalHeights; ii++)
         {
-            initialMap[ii] = 25f;
+            initialMap[ii] = HEIGHT_INITIALIZATION;
         }
         CreateNewTerrainSegment(BSScene.TERRAIN_ID, initialMap, minTerrainCoords, maxTerrainCoords);
     }
@@ -108,7 +128,7 @@ public class BSTerrainManager
             if (BulletSimAPI.RemoveObjectFromWorld2(m_physicsScene.World.Ptr, kvp.Value.Ptr))
             {
                 BulletSimAPI.DestroyObject2(m_physicsScene.World.Ptr, kvp.Value.Ptr);
-                BulletSimAPI.ReleaseHeightmapInfo2(m_heightMaps[kvp.Key].Ptr);
+                BulletSimAPI.ReleaseHeightMapInfo2(m_heightMaps[kvp.Key].Ptr);
             }
         }
         m_terrains.Clear();
@@ -128,30 +148,41 @@ public class BSTerrainManager
         int hSize = heightMap.Length;
         for (int ii = 0; ii < hSize; ii++)
         {
-            minZ = heightMap[ii] < minZ ? heightMap[ii] : minZ;
-            maxZ = heightMap[ii] > maxZ ? heightMap[ii] : maxZ;
+            float height = heightMap[ii];
+            if (height < minZ) minZ = height;
+            if (height > maxZ) maxZ = height;
         }
+        // If the terrain is flat, make a difference so we get a bounding box
+        if (minZ == maxZ) 
+            minZ -= HEIGHT_EQUAL_FUDGE;
+
         minCoords.Z = minZ;
         maxCoords.Z = maxZ;
-        // If the terrain is flat, make a difference so we get a good bounding box
-        if (minZ == maxZ) 
-            minZ -= 0.2f;
         Vector2 terrainRegionBase = new Vector2(minCoords.X, minCoords.Y);
 
         // Create the heightmap data structure in the unmanaged space
-        BulletHeightMapInfo mapInfo = new BulletHeightMapInfo(
-                            BulletSimAPI.CreateHeightmap2(minCoords, maxCoords, heightMap), heightMap);
+        BulletHeightMapInfo mapInfo = new BulletHeightMapInfo(id, heightMap,
+                            BulletSimAPI.CreateHeightMapInfo2(id, minCoords, maxCoords, heightMap, TERRAIN_COLLISION_MARGIN));
         mapInfo.terrainRegionBase = terrainRegionBase;
-        mapInfo.maxRegionExtent = maxCoords;
+        mapInfo.minCoords = minCoords;
+        mapInfo.maxCoords = maxCoords;
         mapInfo.minZ = minZ;
         mapInfo.maxZ = maxZ;
         mapInfo.sizeX = maxCoords.X - minCoords.X;
         mapInfo.sizeY = maxCoords.Y - minCoords.Y;
 
+        Vector3 centerPos;
+        centerPos.X = minCoords.X + (mapInfo.sizeX / 2f);
+        centerPos.Y = minCoords.Y + (mapInfo.sizeY / 2f);
+        centerPos.Z = minZ + (maxZ - minZ) / 2f;
+
         DetailLog("{0},BSScene.CreateNewTerrainSegment,call,minZ={1},maxZ={2},hMapPtr={3},minC={4},maxC={5}",
                     BSScene.DetailLogZero, minZ, maxZ, mapInfo.Ptr, minCoords, maxCoords);
-        // Create the terrain body from that heightmap
-        BulletBody terrainBody = new BulletBody(id, BulletSimAPI.CreateTerrainBody2(id, mapInfo.Ptr, 0.01f));
+        // Create the terrain shape from the mapInfo
+        BulletShape terrainShape = new BulletShape(BulletSimAPI.CreateTerrainShape2(mapInfo.Ptr));
+
+        BulletBody terrainBody = new BulletBody(id, BulletSimAPI.CreateBodyWithDefaultMotionState2(terrainShape.Ptr,
+                       centerPos, Quaternion.Identity)); 
 
         BulletSimAPI.SetFriction2(terrainBody.Ptr, m_physicsScene.Params.terrainFriction);
         BulletSimAPI.SetHitFraction2(terrainBody.Ptr, m_physicsScene.Params.terrainHitFraction);
@@ -163,11 +194,12 @@ public class BSTerrainManager
         BulletSimAPI.AddObjectToWorld2(m_physicsScene.World.Ptr, terrainBody.Ptr);
         BulletSimAPI.UpdateSingleAabb2(m_physicsScene.World.Ptr, terrainBody.Ptr);
 
-
         // Add the created terrain to the management set. If we are doing mega-regions,
         //    the terrains of our children will be added.
         m_terrains.Add(terrainRegionBase, terrainBody);
         m_heightMaps.Add(terrainRegionBase, mapInfo);
+
+        m_terrainModified = true;
     }
 
     public void SetTerrain(float[] heightMap) {
@@ -191,34 +223,57 @@ public class BSTerrainManager
     {
         float minZ = float.MaxValue;
         float maxZ = float.MinValue;
+        Vector2 terrainRegionBase = new Vector2(tOffset.X, tOffset.Y);
 
-        // Copy heightMap local and compute some statistics.
-        // Not really sure if we need to do this deep copy but, given
-        //    the magic that happens to make the closure for taint
-        //    below, I don't want there to be any problem with sharing
-        //    locations of there are multiple calls to this routine
-        //    within one tick.
         int heightMapSize = heightMap.Length;
-        float[] localHeightMap = new float[heightMapSize];
         for (int ii = 0; ii < heightMapSize; ii++)
         {
             float height = heightMap[ii];
             if (height < minZ) minZ = height;
             if (height > maxZ) maxZ = height;
-            localHeightMap[ii] = height;
         }
 
-        Vector2 terrainRegionBase = new Vector2(tOffset.X, tOffset.Y);
+        // The shape of the terrain is from its base to its extents.
+        Vector3 minCoords, maxCoords;
+        minCoords = tOffset;
+        minCoords.Z = minZ;
+        maxCoords = tOffset;
+        maxCoords.X += Constants.RegionSize;
+        maxCoords.Y += Constants.RegionSize;
+        maxCoords.Z = maxZ;
+
+        BulletBody terrainBody;
         BulletHeightMapInfo mapInfo;
         if (m_heightMaps.TryGetValue(terrainRegionBase, out mapInfo))
         {
+            terrainBody = m_terrains[terrainRegionBase];
+            // Copy heightMap local and compute some statistics.
+            for (int ii = 0; ii < heightMapSize; ii++)
+            {
+                mapInfo.heightMap[ii] = heightMap[ii];
+            }
+
             // If this is terrain we know about, it's easy to update
-            mapInfo.heightMap = localHeightMap;
             m_physicsScene.TaintedObject("BSScene.SetTerrain:UpdateExisting", delegate()
             {
                 DetailLog("{0},SetTerrain:UpdateExisting,baseX={1},baseY={2},minZ={3},maxZ={4}", 
                                     BSScene.DetailLogZero, tOffset.X, tOffset.Y, minZ, maxZ);
-                BulletSimAPI.UpdateHeightMap2(m_physicsScene.World.Ptr, mapInfo.Ptr, mapInfo.heightMap);
+                // Fill the existing height map info with the new location and size information
+                BulletSimAPI.FillHeightMapInfo2(mapInfo.Ptr, mapInfo.ID, minCoords, maxCoords, mapInfo.heightMap, TERRAIN_COLLISION_MARGIN);
+
+                // Create a terrain shape based on the new info
+                BulletShape terrainShape = new BulletShape(BulletSimAPI.CreateTerrainShape2(mapInfo.Ptr));
+
+                // Swap the shape in the terrain body (this also deletes the old shape)
+                bool success = BulletSimAPI.ReplaceBodyShape2(m_physicsScene.World.Ptr, terrainBody.Ptr, terrainShape.Ptr);
+
+                if (!success)
+                {
+                    DetailLog("{0},SetTerrain:UpdateExisting,Failed", BSScene.DetailLogZero);
+                    m_physicsScene.Logger.ErrorFormat("{0} Failed updating terrain heightmap. Region={1}",
+                                    LogHeader, m_physicsScene.RegionName);
+                    
+                }
             });
         }
         else
@@ -226,11 +281,6 @@ public class BSTerrainManager
             // Our mega-prim child is giving us a new terrain to add to the phys world
             uint newTerrainID = ++m_terrainCount;
 
-            Vector3 minCoords = tOffset;
-            minCoords.Z = minZ;
-            Vector3 maxCoords = new Vector3(tOffset.X + Constants.RegionSize,
-                                    tOffset.Y + Constants.RegionSize,
-                                    maxZ);
             m_physicsScene.TaintedObject("BSScene.SetTerrain:NewTerrain", delegate()
             {
                 DetailLog("{0},SetTerrain:NewTerrain,baseX={1},baseY={2}", BSScene.DetailLogZero, tOffset.X, tOffset.Y);
@@ -240,9 +290,9 @@ public class BSTerrainManager
     }
 
     // Someday we will have complex terrain with caves and tunnels
-    // For the moment, it's flat and convex
     public float GetTerrainHeightAtXYZ(Vector3 loc)
     {
+        // For the moment, it's flat and convex
         return GetTerrainHeightAtXY(loc.X, loc.Y);
     }
 
@@ -252,9 +302,19 @@ public class BSTerrainManager
     //    the same size and that is the default.
     // Once the heightMapInfo is found, we have all the information to
     //    compute the offset into the array.
+    private float lastHeightTX = 999999f;
+    private float lastHeightTY = 999999f;
+    private float lastHeight = HEIGHT_INITIAL_LASTHEIGHT;
     public float GetTerrainHeightAtXY(float tX, float tY)
     {
-        float ret = 30f;
+        // You'd be surprized at the number of times this routine is called
+        //    with the same parameters as last time.
+        if (!m_terrainModified && lastHeightTX == tX && lastHeightTY == tY)
+            return lastHeight;
+
+        lastHeightTX = tX;
+        lastHeightTY = tY;
+        float ret = HEIGHT_GETHEIGHT_RET;
 
         int offsetX = ((int)(tX / (int)Constants.RegionSize)) * (int)Constants.RegionSize;
         int offsetY = ((int)(tY / (int)Constants.RegionSize)) * (int)Constants.RegionSize;
@@ -265,15 +325,20 @@ public class BSTerrainManager
         {
             float regionX = tX - offsetX;
             float regionY = tY - offsetY;
-            regionX = regionX > mapInfo.sizeX ? 0 : regionX;
-            regionY = regionY > mapInfo.sizeY ? 0 : regionY;
-            ret = mapInfo.heightMap[(int)(regionX * mapInfo.sizeX + regionY)];
+            if (regionX > mapInfo.sizeX) regionX = 0;
+            if (regionY > mapInfo.sizeY) regionY = 0;
+            int mapIndex = (int)regionY * (int)mapInfo.sizeY + (int)regionX;
+            ret = mapInfo.heightMap[mapIndex];
+            m_terrainModified = false;
+            DetailLog("{0},BSTerrainManager.GetTerrainHeightAtXY,bX={1},baseY={2},szX={3},szY={4},regX={5},regY={6},index={7},ht={8}",
+                    BSScene.DetailLogZero, offsetX, offsetY, mapInfo.sizeX, mapInfo.sizeY, regionX, regionY, mapIndex, ret);
         }
         else
         {
             m_physicsScene.Logger.ErrorFormat("{0} GetTerrainHeightAtXY: terrain not found: x={1}, y={2}",
                 LogHeader, tX, tY);
         }
+        lastHeight = ret;
         return ret;
     }
 
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
index 3b319fb..804d2ea 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
@@ -38,13 +38,19 @@ namespace OpenSim.Region.Physics.BulletSPlugin {
 // The physics engine controller class created at initialization
 public struct BulletSim
 {
-    public BulletSim(uint id, BSScene bss, IntPtr xx) { ID = id; scene = bss;  Ptr = xx; }
-    public uint ID;
+    public BulletSim(uint worldId, BSScene bss, IntPtr xx) { worldID = worldId; scene = bss;  Ptr = xx; }
+    public uint worldID;
     // The scene is only in here so very low level routines have a handle to print debug/error messages
     public BSScene scene;
     public IntPtr Ptr;
 }
 
+public struct BulletShape
+{
+    public BulletShape(IntPtr xx) { Ptr = xx; }
+    public IntPtr Ptr;
+}
+
 // An allocated Bullet btRigidBody
 public struct BulletBody
 {
@@ -66,18 +72,22 @@ public struct BulletConstraint
 //      than making copies.
 public class BulletHeightMapInfo
 {
-    public BulletHeightMapInfo(IntPtr xx, float[] hm) { 
+    public BulletHeightMapInfo(uint id, float[] hm, IntPtr xx) {
+        ID = id;
         Ptr = xx;
         heightMap = hm;
         terrainRegionBase = new Vector2(0f, 0f);
-        maxRegionExtent = new Vector3(100f, 100f, 25f);
+        minCoords = new Vector3(100f, 100f, 25f);
+        maxCoords = new Vector3(101f, 101f, 26f);
         minZ = maxZ = 0f;
         sizeX = sizeY = 256f;
     }
+    public uint ID;
     public IntPtr Ptr;
     public float[] heightMap;
     public Vector2 terrainRegionBase;
-    public Vector3 maxRegionExtent;
+    public Vector3 minCoords;
+    public Vector3 maxCoords;
     public float sizeX, sizeY;
     public float minZ, maxZ;
 }
@@ -248,6 +258,10 @@ public enum ConstraintParamAxis : int
 // ===============================================================================
 static class BulletSimAPI {
 
+// Link back to the managed code for outputting log messages
+[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+public delegate void DebugLogCallback([MarshalAs(UnmanagedType.LPStr)]string msg);
+
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 [return: MarshalAs(UnmanagedType.LPStr)]
 public static extern string GetVersion();
@@ -255,7 +269,8 @@ public static extern string GetVersion();
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern uint Initialize(Vector3 maxPosition, IntPtr parms, 
                         int maxCollisions, IntPtr collisionArray, 
-                        int maxUpdates, IntPtr updateArray);
+                        int maxUpdates, IntPtr updateArray,
+                        DebugLogCallback logRoutine);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern void CreateInitialGroundPlaneAndTerrain(uint worldID);
@@ -372,8 +387,6 @@ public static extern Vector3 RecoverFromPenetration(uint worldID, uint id);
 public static extern void DumpBulletStatistics();
 
 // Log a debug message
-[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-public delegate void DebugLogCallback([MarshalAs(UnmanagedType.LPStr)]string msg);
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern void SetDebugLogCallback(DebugLogCallback callback);
 
@@ -407,7 +420,7 @@ public static extern IntPtr Initialize2(Vector3 maxPosition, IntPtr parms,
 public static extern bool UpdateParameter2(IntPtr world, uint localID, String parm, float value);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern void SetHeightmap2(IntPtr world, float[] heightmap);
+public static extern void SetHeightMap2(IntPtr world, float[] heightmap);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern void Shutdown2(IntPtr sim);
@@ -442,25 +455,31 @@ public static extern IntPtr BuildNativeShape2(IntPtr world,
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
 public static extern bool DeleteCollisionShape2(IntPtr world, IntPtr shape);
 
+[DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
+public static extern IntPtr CreateBodyFromShape2(IntPtr sim, IntPtr shape, Vector3 pos, Quaternion rot);
+
+[DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
+public static extern IntPtr CreateBodyWithDefaultMotionState2(IntPtr shape, Vector3 pos, Quaternion rot);
+
+[DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
+public static extern bool ReplaceBodyShape2(IntPtr sim, IntPtr obj, IntPtr shape);
 // =====================================================================================
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateGroundPlaneBody2(uint id, float height, float collisionMargin);
+public static extern IntPtr CreateHeightMapInfo2(uint id, Vector3 minCoords, Vector3 maxCoords, 
+        [MarshalAs(UnmanagedType.LPArray)] float[] heightMap, float collisionMargin);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateTerrainBody2(uint id, 
-                    IntPtr heightMapInfo,
-                    float collisionMargin);
+public static extern IntPtr FillHeightMapInfo2(IntPtr mapInfo, uint id, Vector3 minCoords, Vector3 maxCoords, 
+        [MarshalAs(UnmanagedType.LPArray)] float[] heightMap, float collisionMargin);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern IntPtr CreateHeightmap2(Vector3 minCoords, Vector3 maxCoords, 
-        [MarshalAs(UnmanagedType.LPArray)] float[] heightMap);
+public static extern bool ReleaseHeightMapInfo2(IntPtr heightMapInfo);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern bool ReleaseHeightmapInfo2(IntPtr heightMapInfo);
+public static extern IntPtr CreateGroundPlaneShape2(uint id, float height, float collisionMargin);
 
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]
-public static extern void UpdateHeightMap2(IntPtr world, IntPtr heightMapInfo, 
-            [MarshalAs(UnmanagedType.LPArray)] float[] heightMap);
+public static extern IntPtr CreateTerrainShape2(IntPtr mapInfo);
 
 // =====================================================================================
 [DllImport("BulletSim", CallingConvention = CallingConvention.Cdecl), SuppressUnmanagedCodeSecurity]