7 files changed, 231 insertions, 116 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BS6DofConstraint.cs b/OpenSim/Region/Physics/BulletSPlugin/BS6DofConstraint.cs
index 39a3421..3306a97 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BS6DofConstraint.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BS6DofConstraint.cs
@@ -34,6 +34,10 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
 public class BS6DofConstraint : BSConstraint
 {
+    private static string LogHeader = "[BULLETSIM 6DOF CONSTRAINT]";
+
+    public override ConstraintType Type { get { return ConstraintType.D6_CONSTRAINT_TYPE; } }
+
     // Create a btGeneric6DofConstraint
     public BS6DofConstraint(BulletSim world, BulletBody obj1, BulletBody obj2,
                     Vector3 frame1, Quaternion frame1rot,
@@ -49,6 +53,9 @@ public class BS6DofConstraint : BSConstraint
                                 frame2, frame2rot,
                                 useLinearReferenceFrameA, disableCollisionsBetweenLinkedBodies));
         m_enabled = true;
+        world.physicsScene.DetailLog("{0},BS6DofConstraint,createFrame,wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
+                            BSScene.DetailLogZero, world.worldID,
+                            obj1.ID, obj1.ptr.ToString("X"), obj2.ID, obj2.ptr.ToString("X"));
     }
 
     public BS6DofConstraint(BulletSim world, BulletBody obj1, BulletBody obj2,
@@ -60,12 +67,13 @@ public class BS6DofConstraint : BSConstraint
         m_body2 = obj2;
         if (obj1.ptr == IntPtr.Zero || obj2.ptr == IntPtr.Zero)
         {
-            world.scene.DetailLog("{0},BS6DOFConstraint,badBodyPtr,wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
-                            "[BULLETSIM 6DOF CONSTRAINT]", world.worldID,
+            world.physicsScene.DetailLog("{0},BS6DOFConstraint,badBodyPtr,wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
+                            BSScene.DetailLogZero, world.worldID,
                             obj1.ID, obj1.ptr.ToString("X"), obj2.ID, obj2.ptr.ToString("X"));
-            world.scene.Logger.ErrorFormat("{0} Attempt to build 6DOF constraint with missing bodies: wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
+            world.physicsScene.Logger.ErrorFormat("{0} Attempt to build 6DOF constraint with missing bodies: wID={1}, rID={2}, rBody={3}, cID={4}, cBody={5}",
                             "[BULLETSIM 6DOF CONSTRAINT]", world.worldID,
                             obj1.ID, obj1.ptr.ToString("X"), obj2.ID, obj2.ptr.ToString("X"));
+            m_enabled = false;
         }
         else
         {
@@ -73,8 +81,20 @@ public class BS6DofConstraint : BSConstraint
                                 BulletSimAPI.Create6DofConstraintToPoint2(m_world.ptr, m_body1.ptr, m_body2.ptr,
                                     joinPoint,
                                     useLinearReferenceFrameA, disableCollisionsBetweenLinkedBodies));
+            world.physicsScene.DetailLog("{0},BS6DofConstraint,createMidPoint,wID={1}, csrt={2}, rID={3}, rBody={4}, cID={5}, cBody={6}",
+                                BSScene.DetailLogZero, world.worldID, m_constraint.ptr.ToString("X"),
+                                obj1.ID, obj1.ptr.ToString("X"), obj2.ID, obj2.ptr.ToString("X"));
+            if (m_constraint.ptr == IntPtr.Zero)
+            {
+                world.physicsScene.Logger.ErrorFormat("{0} Failed creation of 6Dof constraint. rootID={1}, childID={2}",
+                                LogHeader, obj1.ID, obj2.ID);
+                m_enabled = false;
+            }
+            else
+            {
+                m_enabled = true;
+            }
         }
-        m_enabled = true;
     }
 
     public bool SetFrames(Vector3 frameA, Quaternion frameArot, Vector3 frameB, Quaternion frameBrot)
@@ -82,7 +102,7 @@ public class BS6DofConstraint : BSConstraint
         bool ret = false;
         if (m_enabled)
         {
-            BulletSimAPI.SetFrames2(m_constraint.Ptr, frameA, frameArot, frameB, frameBrot);
+            BulletSimAPI.SetFrames2(m_constraint.ptr, frameA, frameArot, frameB, frameBrot);
             ret = true;
         }
         return ret;
@@ -93,9 +113,9 @@ public class BS6DofConstraint : BSConstraint
         bool ret = false;
         if (m_enabled)
         {
-            BulletSimAPI.SetConstraintParam2(m_constraint.Ptr, ConstraintParams.BT_CONSTRAINT_STOP_CFM, cfm, ConstraintParamAxis.AXIS_ALL);
-            BulletSimAPI.SetConstraintParam2(m_constraint.Ptr, ConstraintParams.BT_CONSTRAINT_STOP_ERP, erp, ConstraintParamAxis.AXIS_ALL);
-            BulletSimAPI.SetConstraintParam2(m_constraint.Ptr, ConstraintParams.BT_CONSTRAINT_CFM, cfm, ConstraintParamAxis.AXIS_ALL);
+            BulletSimAPI.SetConstraintParam2(m_constraint.ptr, ConstraintParams.BT_CONSTRAINT_STOP_CFM, cfm, ConstraintParamAxis.AXIS_ALL);
+            BulletSimAPI.SetConstraintParam2(m_constraint.ptr, ConstraintParams.BT_CONSTRAINT_STOP_ERP, erp, ConstraintParamAxis.AXIS_ALL);
+            BulletSimAPI.SetConstraintParam2(m_constraint.ptr, ConstraintParams.BT_CONSTRAINT_CFM, cfm, ConstraintParamAxis.AXIS_ALL);
             ret = true;
         }
         return ret;
@@ -106,7 +126,7 @@ public class BS6DofConstraint : BSConstraint
         bool ret = false;
         float onOff = useOffset ? ConfigurationParameters.numericTrue : ConfigurationParameters.numericFalse;
         if (m_enabled)
-            ret = BulletSimAPI.UseFrameOffset2(m_constraint.Ptr, onOff);
+            ret = BulletSimAPI.UseFrameOffset2(m_constraint.ptr, onOff);
         return ret;
     }
 
@@ -115,7 +135,7 @@ public class BS6DofConstraint : BSConstraint
         bool ret = false;
         float onOff = enable ? ConfigurationParameters.numericTrue : ConfigurationParameters.numericFalse;
         if (m_enabled)
-            ret = BulletSimAPI.TranslationalLimitMotor2(m_constraint.Ptr, onOff, targetVelocity, maxMotorForce);
+            ret = BulletSimAPI.TranslationalLimitMotor2(m_constraint.ptr, onOff, targetVelocity, maxMotorForce);
         return ret;
     }
 
@@ -123,7 +143,7 @@ public class BS6DofConstraint : BSConstraint
     {
         bool ret = false;
         if (m_enabled)
-            ret = BulletSimAPI.SetBreakingImpulseThreshold2(m_constraint.Ptr, threshold);
+            ret = BulletSimAPI.SetBreakingImpulseThreshold2(m_constraint.ptr, threshold);
         return ret;
     }
 }
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs b/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
index c21252b..63a4127 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSConstraint.cs
@@ -49,20 +49,23 @@ public abstract class BSConstraint : IDisposable
         if (m_enabled)
         {
             m_enabled = false;
-            bool success = BulletSimAPI.DestroyConstraint2(m_world.ptr, m_constraint.Ptr);
-            m_world.scene.DetailLog("{0},BSConstraint.Dispose,taint,body1={1},body2={2},success={3}", BSScene.DetailLogZero, m_body1.ID, m_body2.ID, success);
-            m_constraint.Ptr = System.IntPtr.Zero;
+            bool success = BulletSimAPI.DestroyConstraint2(m_world.ptr, m_constraint.ptr);
+            m_world.physicsScene.DetailLog("{0},BSConstraint.Dispose,taint,body1={1},body2={2},success={3}", BSScene.DetailLogZero, m_body1.ID, m_body2.ID, success);
+            m_constraint.ptr = System.IntPtr.Zero;
         }
     }
 
     public BulletBody Body1 { get { return m_body1; } }
     public BulletBody Body2 { get { return m_body2; } }
+    public BulletConstraint Constraint { get { return m_constraint; } }
+    public abstract ConstraintType Type { get; }
+
 
     public virtual bool SetLinearLimits(Vector3 low, Vector3 high)
     {
         bool ret = false;
         if (m_enabled)
-            ret = BulletSimAPI.SetLinearLimits2(m_constraint.Ptr, low, high);
+            ret = BulletSimAPI.SetLinearLimits2(m_constraint.ptr, low, high);
         return ret;
     }
 
@@ -70,7 +73,7 @@ public abstract class BSConstraint : IDisposable
     {
         bool ret = false;
         if (m_enabled)
-            ret = BulletSimAPI.SetAngularLimits2(m_constraint.Ptr, low, high);
+            ret = BulletSimAPI.SetAngularLimits2(m_constraint.ptr, low, high);
         return ret;
     }
 
@@ -79,7 +82,7 @@ public abstract class BSConstraint : IDisposable
         bool ret = false;
         if (m_enabled)
         {
-            BulletSimAPI.SetConstraintNumSolverIterations2(m_constraint.Ptr, cnt);
+            BulletSimAPI.SetConstraintNumSolverIterations2(m_constraint.ptr, cnt);
             ret = true;
         }
         return ret;
@@ -91,7 +94,7 @@ public abstract class BSConstraint : IDisposable
         if (m_enabled)
         {
             // Recompute the internal transforms
-            BulletSimAPI.CalculateTransforms2(m_constraint.Ptr);
+            BulletSimAPI.CalculateTransforms2(m_constraint.ptr);
             ret = true;
         }
         return ret;
@@ -110,11 +113,11 @@ public abstract class BSConstraint : IDisposable
                 // Setting an object's mass to zero (making it static like when it's selected)
                 //     automatically disables the constraints.
                 // If the link is enabled, be sure to set the constraint itself to enabled.
-                BulletSimAPI.SetConstraintEnable2(m_constraint.Ptr, m_world.scene.NumericBool(true));
+                BulletSimAPI.SetConstraintEnable2(m_constraint.ptr, m_world.physicsScene.NumericBool(true));
             }
             else
             {
-                m_world.scene.Logger.ErrorFormat("[BULLETSIM CONSTRAINT] CalculateTransforms failed. A={0}, B={1}", Body1.ID, Body2.ID);
+                m_world.physicsScene.Logger.ErrorFormat("[BULLETSIM CONSTRAINT] CalculateTransforms failed. A={0}, B={1}", Body1.ID, Body2.ID);
             }
         }
         return ret;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSHingeConstraint.cs b/OpenSim/Region/Physics/BulletSPlugin/BSHingeConstraint.cs
index a6e4235..7c8a215 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSHingeConstraint.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSHingeConstraint.cs
@@ -34,6 +34,8 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
 class BSHingeConstraint : BSConstraint
 {
+    public override ConstraintType Type { get { return ConstraintType.HINGE_CONSTRAINT_TYPE; } }
+
     public BSHingeConstraint(BulletSim world, BulletBody obj1, BulletBody obj2,
                     Vector3 pivotInA, Vector3 pivotInB,
                     Vector3 axisInA, Vector3 axisInB,
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
index b0cc63c..dff71af 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
@@ -88,6 +88,7 @@ public class BSLinkset
     // Link to a linkset where the child knows the parent.
     // Parent changing should not happen so do some sanity checking.
     // We return the parent's linkset so the child can track its membership.
+    // Called at runtime.
     public BSLinkset AddMeToLinkset(BSPhysObject child)
     {
         lock (m_linksetActivityLock)
@@ -102,6 +103,7 @@ public class BSLinkset
     // Remove a child from a linkset.
     // Returns a new linkset for the child which is a linkset of one (just the
     //    orphened child).
+    // Called at runtime.
     public BSLinkset RemoveMeFromLinkset(BSPhysObject child)
     {
         lock (m_linksetActivityLock)
@@ -113,27 +115,6 @@ public class BSLinkset
             }
 
             RemoveChildFromLinkset(child);
-
-            /* Alternate implementation that destroys the linkset of the root is removed.
-             * This fails because items are added and removed from linksets to build shapes.
-             * Code left for reference.
-            if (IsRoot(child))
-            {
-                // if root of linkset, take the linkset apart
-                while (m_children.Count > 0)
-                {
-                    // Note that we don't do a foreach because the remove routine
-                    //    takes it out of the list.
-                    RemoveChildFromOtherLinkset(m_children[0]);
-                }
-                m_children.Clear(); // just to make sure
-            }
-            else
-            {
-                // Just removing a child from an existing linkset
-                RemoveChildFromLinkset(child);
-            }
-             */
         }
 
         // The child is down to a linkset of just itself
@@ -169,6 +150,106 @@ public class BSLinkset
         return ret;
     }
 
+    // The object is going dynamic (physical). Do any setup necessary
+    //     for a dynamic linkset.
+    // Only the state of the passed object can be modified. The rest of the linkset
+    //     has not yet been fully constructed.
+    // Return 'true' if any properties updated on the passed object.
+    // Called at taint-time!
+    public bool MakeDynamic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // The object is going static (non-physical). Do any setup necessary
+    //     for a static linkset.
+    // Return 'true' if any properties updated on the passed object.
+    // Called at taint-time!
+    public bool MakeStatic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // When physical properties are changed the linkset needs to recalculate
+    //   its internal properties.
+    // Called at runtime.
+    public void Refresh(BSPhysObject requestor)
+    {
+        // If there are no children, there can't be any constraints to recompute
+        if (!HasAnyChildren)
+            return;
+
+        // Only the root does the recomputation
+        if (IsRoot(requestor))
+        {
+            PhysicsScene.TaintedObject("BSLinkSet.Refresh", delegate()
+            {
+                RecomputeLinksetConstraintVariables();
+            });
+        }
+    }
+
+    // Routine used when rebuilding the body of the root of the linkset
+    // Destroy all the constraints have have been made to root.
+    // This is called when the root body is changing.
+    // Called at taint-time!!
+    public void RemoveBodyDependencies(BSPrim child)
+    {
+        lock (m_linksetActivityLock)
+        {
+            if (IsRoot(child))
+            {
+                // If the one with the dependency is root, must undo all children
+                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeChildrenForRoot,rID={1},numChild={2}",
+                                                LinksetRoot.LocalID, m_children.Count);
+                foreach (BSPhysObject bpo in m_children)
+                {
+                    PhysicallyUnlinkAChildFromRoot(LinksetRoot, LinksetRoot.BSBody, bpo, bpo.BSBody);
+                }
+            }
+            else
+            {
+                DetailLog("{0},BSLinkset.RemoveBodyDependencies,removeSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
+                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
+                                                child.LocalID, child.BSBody.ptr.ToString("X"));
+                // Remove the dependency on the body of this one 
+                PhysicallyUnlinkAChildFromRoot(LinksetRoot, LinksetRoot.BSBody, child, child.BSBody);
+            }
+        }
+    }
+
+    // Routine used when rebuilding the body of the root of the linkset
+    // This is called after RemoveAllLinksToRoot() to restore all the constraints.
+    // This is called when the root body has been changed.
+    // Called at taint-time!!
+    public void RestoreBodyDependencies(BSPrim child)
+    {
+        lock (m_linksetActivityLock)
+        {
+            if (IsRoot(child))
+            {
+                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreChildrenForRoot,rID={1},numChild={2}",
+                                                LinksetRoot.LocalID, m_children.Count);
+                foreach (BSPhysObject bpo in m_children)
+                {
+                    PhysicallyLinkAChildToRoot(LinksetRoot, LinksetRoot.BSBody, bpo, bpo.BSBody);
+                }
+            }
+            else
+            {
+                DetailLog("{0},BSLinkset.RestoreBodyDependencies,restoreSingleChild,rID={1},rBody={2},cID={3},cBody={4}",
+                                                LinksetRoot.LocalID, LinksetRoot.BSBody.ptr.ToString("X"),
+                                                child.LocalID, child.BSBody.ptr.ToString("X"));
+                PhysicallyLinkAChildToRoot(LinksetRoot, LinksetRoot.BSBody, child, child.BSBody);
+            }
+        }
+    }
+
+    // ================================================================
+    // Below this point is internal magic
+
     private float ComputeLinksetMass()
     {
         float mass;
@@ -220,46 +301,6 @@ public class BSLinkset
         return com;
     }
 
-    // The object is going dynamic (physical). Do any setup necessary
-    //     for a dynamic linkset.
-    // Only the state of the passed object can be modified. The rest of the linkset
-    //     has not yet been fully constructed.
-    // Return 'true' if any properties updated on the passed object.
-    // Called at taint-time!
-    public bool MakeDynamic(BSPhysObject child)
-    {
-        // What is done for each object in BSPrim is what we want.
-        return false;
-    }
-
-    // The object is going static (non-physical). Do any setup necessary
-    //     for a static linkset.
-    // Return 'true' if any properties updated on the passed object.
-    // Called at taint-time!
-    public bool MakeStatic(BSPhysObject child)
-    {
-        // What is done for each object in BSPrim is what we want.
-        return false;
-    }
-
-    // When physical properties are changed the linkset needs to recalculate
-    //   its internal properties.
-    public void Refresh(BSPhysObject requestor)
-    {
-        // If there are no children, there can't be any constraints to recompute
-        if (!HasAnyChildren)
-            return;
-
-        // Only the root does the recomputation
-        if (IsRoot(requestor))
-        {
-            PhysicsScene.TaintedObject("BSLinkSet.Refresh", delegate()
-            {
-                RecomputeLinksetConstraintVariables();
-            });
-        }
-    }
-
     // Call each of the constraints that make up this linkset and recompute the
     //    various transforms and variables. Used when objects are added or removed
     //    from a linkset to make sure the constraints know about the new mass and
@@ -327,6 +368,11 @@ public class BSLinkset
             BSPhysObject childx = child;
             BulletBody childBodyx = child.BSBody;
 
+            DetailLog("{0},AddChildToLinkset,call,rID={1},rBody={2},cID={3},cBody={4}", 
+                            rootx.LocalID,
+                            rootx.LocalID, rootBodyx.ptr.ToString("X"),
+                            childx.LocalID, childBodyx.ptr.ToString("X"));
+
             PhysicsScene.TaintedObject("AddChildToLinkset", delegate()
             {
                 DetailLog("{0},AddChildToLinkset,taint,child={1}", LinksetRoot.LocalID, child.LocalID);
@@ -358,10 +404,14 @@ public class BSLinkset
             BulletBody rootBodyx = LinksetRoot.BSBody;
             BSPhysObject childx = child;
             BulletBody childBodyx = child.BSBody;
+
+            DetailLog("{0},RemoveChildFromLinkset,call,child={1}", 
+                            rootx.LocalID,
+                            rootx.LocalID, rootBodyx.ptr.ToString("X"),
+                            childx.LocalID, childBodyx.ptr.ToString("X"));
+
             PhysicsScene.TaintedObject("RemoveChildFromLinkset", delegate()
             {
-                DetailLog("{0},RemoveChildFromLinkset,taint,child={1}", LinksetRoot.LocalID, child.LocalID);
-
                 PhysicallyUnlinkAChildFromRoot(rootx, rootBodyx, childx, childBodyx);
                 RecomputeLinksetConstraintVariables();
             });
@@ -390,14 +440,15 @@ public class BSLinkset
         // real world coordinate of midpoint between the two objects
         OMV.Vector3 midPoint = rootPrim.Position + (childRelativePosition / 2);
 
-        // create a constraint that allows no freedom of movement between the two objects
-        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
         DetailLog("{0},PhysicallyLinkAChildToRoot,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
                                         rootPrim.LocalID,
                                         rootPrim.LocalID, rootBody.ptr.ToString("X"),
                                         childPrim.LocalID, childBody.ptr.ToString("X"),
                                         rootPrim.Position, childPrim.Position, midPoint);
 
+        // create a constraint that allows no freedom of movement between the two objects
+        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
+
         // There is great subtlty in these paramters. Notice the check for a ptr of zero.
         // We pass the BulletBody structure into the taint in order to capture the pointer
         //     of the body at the time of constraint creation. This doesn't work for the very first
@@ -416,6 +467,7 @@ public class BSLinkset
                         true,
                         true
                         );
+
         /* NOTE: below is an attempt to build constraint with full frame computation, etc.
          *     Using the midpoint is easier since it lets the Bullet code manipulate the transforms
          *     of the objects.
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index 8688485..c879143 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -1111,13 +1111,21 @@ public sealed class BSPrim : BSPhysObject
         // Undo me from any possible linkset so, if body is rebuilt, the link will get restored.
         // NOTE that the new linkset is not set. This saves the handle to the linkset
         //     so we can add ourselves back when shape mangling is complete.
-        Linkset.RemoveMeFromLinkset(this);
+        bool needToRestoreLinkset = false;
 
         // Create the correct physical representation for this type of object.
         // Updates BSBody and BSShape with the new information.
-        PhysicsScene.Shapes.GetBodyAndShape(forceRebuild, PhysicsScene.World, this, shapeData, _pbs);
+        PhysicsScene.Shapes.GetBodyAndShape(forceRebuild, PhysicsScene.World, this, shapeData, _pbs, 
+                        null, delegate(BulletBody dBody)
+        {
+            // Called if the current prim body is about to be destroyed.
+            // The problem is the constraints for Linksets which need to be updated for the new body.
+            Linkset.RemoveBodyDependencies(this);
+            needToRestoreLinkset = true;
+        });
 
-        Linkset = Linkset.AddMeToLinkset(this);
+        if (needToRestoreLinkset)
+            Linkset.RestoreBodyDependencies(this);
 
         // Make sure the properties are set on the new object
         UpdatePhysicalParameters();
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
index b428ba3..2618971 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSShapeCollection.cs
@@ -81,12 +81,21 @@ public class BSShapeCollection : IDisposable
         // TODO!!!!!!!!!
     }
 
+    // Callbacks called just before either the body or shape is destroyed.
+    // Mostly used for changing bodies out from under Linksets.
+    // Useful for other cases where parameters need saving.
+    // Passing 'null' says no callback.
+    public delegate void ShapeDestructionCallback(BulletShape shape);
+    public delegate void BodyDestructionCallback(BulletBody body);
+
     // Called to update/change the body and shape for an object.
     // First checks the shape and updates that if necessary then makes
     //    sure the body is of the right type.
     // Return 'true' if either the body or the shape changed.
     // Called at taint-time!!
-    public bool GetBodyAndShape(bool forceRebuild, BulletSim sim, BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    public bool GetBodyAndShape(bool forceRebuild, BulletSim sim, BSPrim prim, 
+                    ShapeData shapeData, PrimitiveBaseShape pbs,
+                    ShapeDestructionCallback shapeCallback, BodyDestructionCallback bodyCallback)
     {
         bool ret = false;
 
@@ -95,11 +104,11 @@ public class BSShapeCollection : IDisposable
         {
             // Do we have the correct geometry for this type of object?
             // Updates prim.BSShape with information/pointers to requested shape
-            bool newGeom = CreateGeom(forceRebuild, prim, shapeData, pbs);
+            bool newGeom = CreateGeom(forceRebuild, prim, shapeData, pbs, shapeCallback);
             // If we had to select a new shape geometry for the object,
             //    rebuild the body around it.
             // Updates prim.BSBody with information/pointers to requested body
-            bool newBody = CreateBody((newGeom || forceRebuild), prim, PhysicsScene.World, prim.BSShape, shapeData);
+            bool newBody = CreateBody((newGeom || forceRebuild), prim, PhysicsScene.World, prim.BSShape, shapeData, bodyCallback);
             ret = newGeom || newBody;
         }
         DetailLog("{0},BSShapeCollection.GetBodyAndShape,force={1},ret={2},body={3},shape={4}",
@@ -135,7 +144,7 @@ public class BSShapeCollection : IDisposable
 
     // Release the usage of a body.
     // Called when releasing use of a BSBody. BSShape is handled separately.
-    public void DereferenceBody(BulletBody shape, bool inTaintTime)
+    public void DereferenceBody(BulletBody shape, bool inTaintTime, BodyDestructionCallback bodyCallback )
     {
         if (shape.ptr == IntPtr.Zero)
             return;
@@ -244,7 +253,7 @@ public class BSShapeCollection : IDisposable
 
     // Release the usage of a shape.
     // The collisionObject is released since it is a copy of the real collision shape.
-    private void DereferenceShape(BulletShape shape, bool atTaintTime)
+    private void DereferenceShape(BulletShape shape, bool atTaintTime, ShapeDestructionCallback shapeCallback)
     {
         if (shape.ptr == IntPtr.Zero)
             return;
@@ -254,10 +263,10 @@ public class BSShapeCollection : IDisposable
             switch (shape.type)
             {
                 case ShapeData.PhysicsShapeType.SHAPE_HULL:
-                    DereferenceHull(shape);
+                    DereferenceHull(shape, shapeCallback);
                     break;
                 case ShapeData.PhysicsShapeType.SHAPE_MESH:
-                    DereferenceMesh(shape);
+                    DereferenceMesh(shape, shapeCallback);
                     break;
                 case ShapeData.PhysicsShapeType.SHAPE_UNKNOWN:
                     break;
@@ -267,6 +276,7 @@ public class BSShapeCollection : IDisposable
                     {
                         DetailLog("{0},BSShapeCollection.DereferenceShape,deleteNativeShape,ptr={1},taintTime={2}",
                                         BSScene.DetailLogZero, shape.ptr.ToString("X"), atTaintTime);
+                        if (shapeCallback != null) shapeCallback(shape);
                         BulletSimAPI.DeleteCollisionShape2(PhysicsScene.World.ptr, shape.ptr);
                     }
                     break;
@@ -287,13 +297,14 @@ public class BSShapeCollection : IDisposable
 
     // Count down the reference count for a mesh shape
     // Called at taint-time.
-    private void DereferenceMesh(BulletShape shape)
+    private void DereferenceMesh(BulletShape shape, ShapeDestructionCallback shapeCallback)
     {
         MeshDesc meshDesc;
         if (Meshes.TryGetValue(shape.shapeKey, out meshDesc))
         {
             meshDesc.referenceCount--;
             // TODO: release the Bullet storage
+            if (shapeCallback != null) shapeCallback(shape);
             meshDesc.lastReferenced = System.DateTime.Now;
             Meshes[shape.shapeKey] = meshDesc;
             DetailLog("{0},BSShapeCollection.DereferenceMesh,key={1},refCnt={2}",
@@ -304,13 +315,14 @@ public class BSShapeCollection : IDisposable
 
     // Count down the reference count for a hull shape
     // Called at taint-time.
-    private void DereferenceHull(BulletShape shape)
+    private void DereferenceHull(BulletShape shape, ShapeDestructionCallback shapeCallback)
     {
         HullDesc hullDesc;
         if (Hulls.TryGetValue(shape.shapeKey, out hullDesc))
         {
             hullDesc.referenceCount--;
             // TODO: release the Bullet storage (aging old entries?)
+            if (shapeCallback != null) shapeCallback(shape);
             hullDesc.lastReferenced = System.DateTime.Now;
             Hulls[shape.shapeKey] = hullDesc;
             DetailLog("{0},BSShapeCollection.DereferenceHull,key={1},refCnt={2}",
@@ -324,7 +336,8 @@ public class BSShapeCollection : IDisposable
     // if 'forceRebuild' is true, the geometry is rebuilt. Otherwise a previously built version is used.
     // Returns 'true' if the geometry was rebuilt.
     // Called at taint-time!
-    private bool CreateGeom(bool forceRebuild, BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    private bool CreateGeom(bool forceRebuild, BSPrim prim, ShapeData shapeData, 
+                            PrimitiveBaseShape pbs, ShapeDestructionCallback shapeCallback)
     {
         bool ret = false;
         bool haveShape = false;
@@ -349,8 +362,8 @@ public class BSShapeCollection : IDisposable
                         || prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_SPHERE
                         )
                 {
-                    ret = GetReferenceToNativeShape(prim, shapeData,
-                            ShapeData.PhysicsShapeType.SHAPE_SPHERE, ShapeData.FixedShapeKey.KEY_SPHERE);
+                    ret = GetReferenceToNativeShape(prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_SPHERE, 
+                                            ShapeData.FixedShapeKey.KEY_SPHERE, shapeCallback);
                     DetailLog("{0},BSShapeCollection.CreateGeom,sphere,force={1},shape={2}",
                                         prim.LocalID, forceRebuild, prim.BSShape);
                 }
@@ -363,8 +376,8 @@ public class BSShapeCollection : IDisposable
                         || prim.BSShape.type != ShapeData.PhysicsShapeType.SHAPE_BOX
                         )
                 {
-                    ret = GetReferenceToNativeShape(
-                        prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_BOX, ShapeData.FixedShapeKey.KEY_BOX);
+                    ret = GetReferenceToNativeShape( prim, shapeData, ShapeData.PhysicsShapeType.SHAPE_BOX, 
+                                            ShapeData.FixedShapeKey.KEY_BOX, shapeCallback);
                     DetailLog("{0},BSShapeCollection.CreateGeom,box,force={1},shape={2}",
                                         prim.LocalID, forceRebuild, prim.BSShape);
                 }
@@ -378,13 +391,13 @@ public class BSShapeCollection : IDisposable
             if (prim.IsPhysical)
             {
                 // Update prim.BSShape to reference a hull of this shape.
-                ret = GetReferenceToHull(prim, shapeData, pbs);
+                ret = GetReferenceToHull(prim, shapeData, pbs, shapeCallback);
                 DetailLog("{0},BSShapeCollection.CreateGeom,hull,shape={1},key={2}",
                                         shapeData.ID, prim.BSShape, prim.BSShape.shapeKey.ToString("X"));
             }
             else
             {
-                ret = GetReferenceToMesh(prim, shapeData, pbs);
+                ret = GetReferenceToMesh(prim, shapeData, pbs, shapeCallback);
                 DetailLog("{0},BSShapeCollection.CreateGeom,mesh,shape={1},key={2}",
                                         shapeData.ID, prim.BSShape, prim.BSShape.shapeKey.ToString("X"));
             }
@@ -394,7 +407,8 @@ public class BSShapeCollection : IDisposable
 
     // Creates a native shape and assignes it to prim.BSShape
     private bool GetReferenceToNativeShape( BSPrim prim, ShapeData shapeData,
-                            ShapeData.PhysicsShapeType shapeType, ShapeData.FixedShapeKey shapeKey)
+                            ShapeData.PhysicsShapeType shapeType, ShapeData.FixedShapeKey shapeKey,
+                            ShapeDestructionCallback shapeCallback)
     {
         BulletShape newShape;
 
@@ -404,7 +418,7 @@ public class BSShapeCollection : IDisposable
         shapeData.Scale = shapeData.Size;
 
         // release any previous shape
-        DereferenceShape(prim.BSShape, true);
+        DereferenceShape(prim.BSShape, true, shapeCallback);
 
         // Native shapes are always built independently.
         newShape = new BulletShape(BulletSimAPI.BuildNativeShape2(PhysicsScene.World.ptr, shapeData), shapeType);
@@ -422,7 +436,8 @@ public class BSShapeCollection : IDisposable
     // Dereferences previous shape in BSShape and adds a reference for this new shape.
     // Returns 'true' of a mesh was actually built. Otherwise .
     // Called at taint-time!
-    private bool GetReferenceToMesh(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    private bool GetReferenceToMesh(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs,
+                                ShapeDestructionCallback shapeCallback)
     {
         BulletShape newShape = new BulletShape(IntPtr.Zero);
 
@@ -436,7 +451,7 @@ public class BSShapeCollection : IDisposable
                                 prim.LocalID, prim.BSShape.shapeKey.ToString("X"), newMeshKey.ToString("X"));
 
         // Since we're recreating new, get rid of the reference to the previous shape
-        DereferenceShape(prim.BSShape, true);
+        DereferenceShape(prim.BSShape, true, shapeCallback);
 
         newShape = CreatePhysicalMesh(prim.PhysObjectName, newMeshKey, pbs, shapeData.Size, lod);
 
@@ -490,7 +505,8 @@ public class BSShapeCollection : IDisposable
 
     // See that hull shape exists in the physical world and update prim.BSShape.
     // We could be creating the hull because scale changed or whatever.
-    private bool GetReferenceToHull(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs)
+    private bool GetReferenceToHull(BSPrim prim, ShapeData shapeData, PrimitiveBaseShape pbs,
+                                ShapeDestructionCallback shapeCallback)
     {
         BulletShape newShape;
 
@@ -505,7 +521,7 @@ public class BSShapeCollection : IDisposable
                         prim.LocalID, prim.BSShape.shapeKey.ToString("X"), newHullKey.ToString("X"));
 
         // Remove usage of the previous shape. Also removes reference to underlying mesh if it is a hull.
-        DereferenceShape(prim.BSShape, true);
+        DereferenceShape(prim.BSShape, true, shapeCallback);
 
         newShape = CreatePhysicalHull(prim.PhysObjectName, newHullKey, pbs, shapeData.Size, lod);
 
@@ -656,7 +672,8 @@ public class BSShapeCollection : IDisposable
     // Updates prim.BSBody with the information about the new body if one is created.
     // Returns 'true' if an object was actually created.
     // Called at taint-time.
-    private bool CreateBody(bool forceRebuild, BSPrim prim, BulletSim sim, BulletShape shape, ShapeData shapeData)
+    private bool CreateBody(bool forceRebuild, BSPrim prim, BulletSim sim, BulletShape shape, 
+                            ShapeData shapeData, BodyDestructionCallback bodyCallback)
     {
         bool ret = false;
 
@@ -679,7 +696,7 @@ public class BSShapeCollection : IDisposable
 
         if (mustRebuild || forceRebuild)
         {
-            DereferenceBody(prim.BSBody, true);
+            DereferenceBody(prim.BSBody, true, bodyCallback);
 
             BulletBody aBody;
             IntPtr bodyPtr = IntPtr.Zero;
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
index 544c53d..1125d7e 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BulletSimAPI.cs
@@ -42,12 +42,12 @@ public struct BulletSim
     {
         ptr = xx;
         worldID = worldId;
-        scene = bss;
+        physicsScene = bss;
     }
     public IntPtr ptr;
     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 BSScene physicsScene;
 }
 
 // An allocated Bullet btRigidBody
@@ -120,14 +120,27 @@ public struct BulletShape
     }
 }
 
+    // Constraint type values as defined by Bullet
+public enum ConstraintType : int
+{
+        POINT2POINT_CONSTRAINT_TYPE = 3,
+        HINGE_CONSTRAINT_TYPE,
+        CONETWIST_CONSTRAINT_TYPE,
+        D6_CONSTRAINT_TYPE,
+        SLIDER_CONSTRAINT_TYPE,
+        CONTACT_CONSTRAINT_TYPE,
+        D6_SPRING_CONSTRAINT_TYPE,
+        MAX_CONSTRAINT_TYPE
+}
+
 // An allocated Bullet btConstraint
 public struct BulletConstraint
 {
     public BulletConstraint(IntPtr xx)
     {
-        Ptr = xx;
+        ptr = xx;
     }
-    public IntPtr Ptr;
+    public IntPtr ptr;
 }
 
 // An allocated HeightMapThing which holds various heightmap info.