1 files changed, 299 insertions, 151 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index 9c20004..26a581f 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -37,13 +37,11 @@ using OpenSim.Region.Physics.ConvexDecompositionDotNet;
 namespace OpenSim.Region.Physics.BulletSPlugin
 {
     [Serializable]
-public sealed class BSPrim : PhysicsActor
+public sealed class BSPrim : BSPhysObject
 {
     private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
     private static readonly string LogHeader = "[BULLETS PRIM]";
 
-    private void DebugLog(string mm, params Object[] xx) { if (_scene.ShouldDebugLog) m_log.DebugFormat(mm, xx); }
-
     private IMesh _mesh;
     private PrimitiveBaseShape _pbs;
     private ShapeData.PhysicsShapeType _shapeType;
@@ -90,23 +88,16 @@ public sealed class BSPrim : PhysicsActor
     private float _buoyancy;
 
     // Membership in a linkset is controlled by this class.
-    private BSLinkset _linkset;
-    public BSLinkset Linkset
-    {
-        get { return _linkset; }
-        set { _linkset = value; }
-    }
+    public override BSLinkset Linkset { get; set; }
 
     private int _subscribedEventsMs = 0;
     private int _nextCollisionOkTime = 0;
     long _collidingStep;
     long _collidingGroundStep;
+    CollisionFlags m_currentCollisionFlags = 0;
 
-    private BulletBody m_body;
-    public BulletBody Body { 
-        get { return m_body; }
-        set { m_body = value; }
-    }
+    public override BulletBody BSBody { get; set; }
+    public override BulletShape BSShape { get; set; }
 
     private BSDynamics _vehicle;
 
@@ -124,6 +115,7 @@ public sealed class BSPrim : PhysicsActor
         // m_log.DebugFormat("{0}: BSPrim creation of {1}, id={2}", LogHeader, primName, localID);
         _localID = localID;
         _avName = primName;
+        _physicsActorType = (int)ActorTypes.Prim;
         _scene = parent_scene;
         _position = pos;
         _size = size;
@@ -141,35 +133,37 @@ public sealed class BSPrim : PhysicsActor
         _friction = _scene.Params.defaultFriction;  // TODO: compute based on object material
         _density = _scene.Params.defaultDensity;    // TODO: compute based on object material
         _restitution = _scene.Params.defaultRestitution;
-        _linkset = new BSLinkset(_scene, this);     // a linkset of one
-        _vehicle = new BSDynamics(this);            // add vehicleness
+        Linkset = new BSLinkset(Scene, this);     // a linkset of one
+        _vehicle = new BSDynamics(Scene, this);            // add vehicleness
         _mass = CalculateMass();
-        // do the actual object creation at taint time
         DetailLog("{0},BSPrim.constructor,call", LocalID);
+        // do the actual object creation at taint time
         _scene.TaintedObject("BSPrim.create", delegate()
         {
-            RecreateGeomAndObject();
+            CreateGeomAndObject(true);
 
             // Get the pointer to the physical body for this object.
             // At the moment, we're still letting BulletSim manage the creation and destruction
             //    of the object. Someday we'll move that into the C# code.
-            m_body = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(_scene.World.Ptr, LocalID));
+            BSBody = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(_scene.World.Ptr, LocalID));
+            BSShape = new BulletShape(BulletSimAPI.GetCollisionShape2(BSBody.Ptr));
+            m_currentCollisionFlags = BulletSimAPI.GetCollisionFlags2(BSBody.Ptr);
         });
     }
 
     // called when this prim is being destroyed and we should free all the resources
-    public void Destroy()
+    public override void Destroy()
     {
         // m_log.DebugFormat("{0}: Destroy, id={1}", LogHeader, LocalID);
 
         // Undo any links between me and any other object
-        BSPrim parentBefore = _linkset.LinksetRoot;
-        int childrenBefore = _linkset.NumberOfChildren;
+        BSPhysObject parentBefore = Linkset.LinksetRoot;
+        int childrenBefore = Linkset.NumberOfChildren;
 
-        _linkset = _linkset.RemoveMeFromLinkset(this);
+        Linkset = Linkset.RemoveMeFromLinkset(this);
 
         DetailLog("{0},BSPrim.Destroy,call,parentBefore={1},childrenBefore={2},parentAfter={3},childrenAfter={4}",
-            LocalID, parentBefore.LocalID, childrenBefore, _linkset.LinksetRoot.LocalID, _linkset.NumberOfChildren);
+            LocalID, parentBefore.LocalID, childrenBefore, Linkset.LinksetRoot.LocalID, Linkset.NumberOfChildren);
 
         // Undo any vehicle properties
         this.VehicleType = (int)Vehicle.TYPE_NONE;
@@ -192,9 +186,10 @@ public sealed class BSPrim : PhysicsActor
             _scene.TaintedObject("BSPrim.setSize", delegate()
             {
                 _mass = CalculateMass();   // changing size changes the mass
-                BulletSimAPI.SetObjectScaleMass(_scene.WorldID, _localID, _scale, (IsPhysical ? _mass : 0f), IsPhysical);
-                // DetailLog("{0}: BSPrim.setSize: size={1}, mass={2}, physical={3}", LocalID, _size, _mass, IsPhysical);
-                RecreateGeomAndObject();
+                // Since _size changed, the mesh needs to be rebuilt. If rebuilt, all the correct
+                //   scale and margins are set.
+                CreateGeomAndObject(true);
+                DetailLog("{0}: BSPrim.setSize: size={1}, scale={2}, mass={3}, physical={4}", LocalID, _size, _scale, _mass, IsPhysical);
             });
         } 
     }
@@ -204,7 +199,7 @@ public sealed class BSPrim : PhysicsActor
             _scene.TaintedObject("BSPrim.setShape", delegate()
             {
                 _mass = CalculateMass();   // changing the shape changes the mass
-                RecreateGeomAndObject();
+                CreateGeomAndObject(false);
             });
         } 
     }
@@ -232,14 +227,13 @@ public sealed class BSPrim : PhysicsActor
         BSPrim parent = obj as BSPrim;
         if (parent != null)
         {
-            DebugLog("{0}: link {1}/{2} to {3}", LogHeader, _avName, _localID, parent.LocalID);
-            BSPrim parentBefore = _linkset.LinksetRoot;
-            int childrenBefore = _linkset.NumberOfChildren;
+            BSPhysObject parentBefore = Linkset.LinksetRoot;
+            int childrenBefore = Linkset.NumberOfChildren;
 
-            _linkset = parent.Linkset.AddMeToLinkset(this);
+            Linkset = parent.Linkset.AddMeToLinkset(this);
 
             DetailLog("{0},BSPrim.link,call,parentBefore={1}, childrenBefore=={2}, parentAfter={3}, childrenAfter={4}", 
-                LocalID, parentBefore.LocalID, childrenBefore, _linkset.LinksetRoot.LocalID, _linkset.NumberOfChildren);
+                LocalID, parentBefore.LocalID, childrenBefore, Linkset.LinksetRoot.LocalID, Linkset.NumberOfChildren);
         }
         return; 
     }
@@ -248,16 +242,14 @@ public sealed class BSPrim : PhysicsActor
     public override void delink() {
         // TODO: decide if this parent checking needs to happen at taint time
         // Race condition here: if link() and delink() in same simulation tick, the delink will not happen
-        DebugLog("{0}: delink {1}/{2}. Parent={3}", LogHeader, _avName, _localID, 
-                            _linkset.LinksetRoot._avName+"/"+_linkset.LinksetRoot.LocalID.ToString());
 
-        BSPrim parentBefore = _linkset.LinksetRoot;
-        int childrenBefore = _linkset.NumberOfChildren;
+        BSPhysObject parentBefore = Linkset.LinksetRoot;
+        int childrenBefore = Linkset.NumberOfChildren;
         
-        _linkset = _linkset.RemoveMeFromLinkset(this);
+        Linkset = Linkset.RemoveMeFromLinkset(this);
 
         DetailLog("{0},BSPrim.delink,parentBefore={1},childrenBefore={2},parentAfter={3},childrenAfter={4}, ", 
-            LocalID, parentBefore.LocalID, childrenBefore, _linkset.LinksetRoot.LocalID, _linkset.NumberOfChildren);
+            LocalID, parentBefore.LocalID, childrenBefore, Linkset.LinksetRoot.LocalID, Linkset.NumberOfChildren);
         return; 
     }
 
@@ -265,30 +257,30 @@ public sealed class BSPrim : PhysicsActor
     // Do it to the properties so the values get set in the physics engine.
     // Push the setting of the values to the viewer.
     // Called at taint time!
-    public void ZeroMotion()
+    public override void ZeroMotion()
     {
         _velocity = OMV.Vector3.Zero;
         _acceleration = OMV.Vector3.Zero;
         _rotationalVelocity = OMV.Vector3.Zero;
 
         // Zero some other properties directly into the physics engine
-        BulletSimAPI.SetVelocity2(Body.Ptr, OMV.Vector3.Zero);
-        BulletSimAPI.SetAngularVelocity2(Body.Ptr, OMV.Vector3.Zero);
-        BulletSimAPI.SetInterpolation2(Body.Ptr, OMV.Vector3.Zero, OMV.Vector3.Zero);
-        BulletSimAPI.ClearForces2(Body.Ptr);
+        BulletSimAPI.SetLinearVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
+        BulletSimAPI.SetAngularVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
+        BulletSimAPI.SetInterpolationVelocity2(BSBody.Ptr, OMV.Vector3.Zero, OMV.Vector3.Zero);
+        BulletSimAPI.ClearForces2(BSBody.Ptr);
     }
 
     public override void LockAngularMotion(OMV.Vector3 axis)
     { 
-        // DetailLog("{0},BSPrim.LockAngularMotion,call,axis={1}", LocalID, axis);
+        DetailLog("{0},BSPrim.LockAngularMotion,call,axis={1}", LocalID, axis);
         return;
     }
 
     public override OMV.Vector3 Position { 
         get { 
-            if (!_linkset.IsRoot(this))
+            if (!Linkset.IsRoot(this))
                 // child prims move around based on their parent. Need to get the latest location
-                _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
+                _position = BulletSimAPI.GetPosition2(BSBody.Ptr);
 
             // don't do the GetObjectPosition for root elements because this function is called a zillion times
             // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
@@ -299,8 +291,8 @@ public sealed class BSPrim : PhysicsActor
             // TODO: what does it mean to set the position of a child prim?? Rebuild the constraint?
             _scene.TaintedObject("BSPrim.setPosition", delegate()
             {
-                // DetailLog("{0},BSPrim.SetPosition,taint,pos={1},orient={2}", LocalID, _position, _orientation);
-                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                DetailLog("{0},BSPrim.SetPosition,taint,pos={1},orient={2}", LocalID, _position, _orientation);
+                BulletSimAPI.SetTranslation2(BSBody.Ptr, _position, _orientation);
             });
         } 
     }
@@ -311,23 +303,24 @@ public sealed class BSPrim : PhysicsActor
     { 
         get
         {
-            return _linkset.LinksetMass;
+            // return Linkset.LinksetMass;
+            return _mass;
         }
     }
 
     // used when we only want this prim's mass and not the linkset thing
-    public float MassRaw { get { return _mass; } }
+    public override float MassRaw { get { return _mass; }  }
 
     // Is this used?
     public override OMV.Vector3 CenterOfMass
     {
-        get { return _linkset.CenterOfMass; }
+        get { return Linkset.CenterOfMass; }
     }
 
     // Is this used?
     public override OMV.Vector3 GeometricCenter
     {
-        get { return _linkset.GeometricCenter; }
+        get { return Linkset.GeometricCenter; }
     }
 
     public override OMV.Vector3 Force { 
@@ -336,9 +329,8 @@ public sealed class BSPrim : PhysicsActor
             _force = value;
             _scene.TaintedObject("BSPrim.setForce", delegate()
             {
-                // DetailLog("{0},BSPrim.setForce,taint,force={1}", LocalID, _force);
-                // BulletSimAPI.SetObjectForce(_scene.WorldID, _localID, _force);
-                BulletSimAPI.SetObjectForce2(Body.Ptr, _force);
+                DetailLog("{0},BSPrim.setForce,taint,force={1}", LocalID, _force);
+                BulletSimAPI.SetObjectForce2(BSBody.Ptr, _force);
             });
         } 
     }
@@ -364,14 +356,14 @@ public sealed class BSPrim : PhysicsActor
     {
         _scene.TaintedObject("BSPrim.VehicleFloatParam", delegate()
         {
-            _vehicle.ProcessFloatVehicleParam((Vehicle)param, value, _scene.LastSimulatedTimestep);
+            _vehicle.ProcessFloatVehicleParam((Vehicle)param, value);
         });
     }
     public override void VehicleVectorParam(int param, OMV.Vector3 value) 
     {
         _scene.TaintedObject("BSPrim.VehicleVectorParam", delegate()
         {
-            _vehicle.ProcessVectorVehicleParam((Vehicle)param, value, _scene.LastSimulatedTimestep);
+            _vehicle.ProcessVectorVehicleParam((Vehicle)param, value);
         });
     }
     public override void VehicleRotationParam(int param, OMV.Quaternion rotation) 
@@ -391,7 +383,7 @@ public sealed class BSPrim : PhysicsActor
 
     // Called each simulation step to advance vehicle characteristics.
     // Called from Scene when doing simulation step so we're in taint processing time.
-    public void StepVehicle(float timeStep)
+    public override void StepVehicle(float timeStep)
     {
         if (IsPhysical)
             _vehicle.Step(timeStep);
@@ -414,15 +406,15 @@ public sealed class BSPrim : PhysicsActor
             _velocity = value;
             _scene.TaintedObject("BSPrim.setVelocity", delegate()
             {
-                // DetailLog("{0},BSPrim.SetVelocity,taint,vel={1}", LocalID, _velocity);
-                BulletSimAPI.SetObjectVelocity(_scene.WorldID, LocalID, _velocity);
+                DetailLog("{0},BSPrim.SetVelocity,taint,vel={1}", LocalID, _velocity);
+                BulletSimAPI.SetLinearVelocity2(BSBody.Ptr, _velocity);
             });
         } 
     }
     public override OMV.Vector3 Torque { 
         get { return _torque; } 
         set { _torque = value; 
-            // DetailLog("{0},BSPrim.SetTorque,call,torque={1}", LocalID, _torque);
+            DetailLog("{0},BSPrim.SetTorque,call,torque={1}", LocalID, _torque);
         } 
     }
     public override float CollisionScore { 
@@ -436,10 +428,10 @@ public sealed class BSPrim : PhysicsActor
     }
     public override OMV.Quaternion Orientation { 
         get {
-            if (!_linkset.IsRoot(this))
+            if (!Linkset.IsRoot(this))
             {
                 // Children move around because tied to parent. Get a fresh value.
-                _orientation = BulletSimAPI.GetObjectOrientation(_scene.WorldID, LocalID);
+                _orientation = BulletSimAPI.GetOrientation2(BSBody.Ptr);
             }
             return _orientation;
         } 
@@ -449,15 +441,14 @@ public sealed class BSPrim : PhysicsActor
             _scene.TaintedObject("BSPrim.setOrientation", delegate()
             {
                 // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
-                // DetailLog("{0},BSPrim.setOrientation,taint,pos={1},orient={2}", LocalID, _position, _orientation);
-                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                DetailLog("{0},BSPrim.setOrientation,taint,pos={1},orient={2}", LocalID, _position, _orientation);
+                BulletSimAPI.SetTranslation2(BSBody.Ptr, _position, _orientation);
             });
         } 
     }
     public override int PhysicsActorType { 
         get { return _physicsActorType; } 
-        set { _physicsActorType = value; 
-        } 
+        set { _physicsActorType = value; } 
     }
     public override bool IsPhysical { 
         get { return _isPhysical; } 
@@ -484,30 +475,139 @@ public sealed class BSPrim : PhysicsActor
 
     // Make gravity work if the object is physical and not selected
     // No locking here because only called when it is safe
+    // There are four flags we're interested in:
+    //     IsStatic: Object does not move, otherwise the object has mass and moves
+    //     isSolid: other objects bounce off of this object
+    //     isVolumeDetect: other objects pass through but can generate collisions
+    //     collisionEvents: whether this object returns collision events
     private void SetObjectDynamic()
     {
-        // RA: remove this for the moment.
-        // The problem is that dynamic objects are hulls so if we are becoming physical
-        //    the shape has to be checked and possibly built.
-        //    Maybe a VerifyCorrectPhysicalShape() routine?
-        // RecreateGeomAndObject();
+        // If it's becoming dynamic, it will need hullness
+        VerifyCorrectPhysicalShape();
+        UpdatePhysicalParameters();
+    }
 
+    private void UpdatePhysicalParameters()
+    {
+        /*
         // Bullet wants static objects to have a mass of zero
         float mass = IsStatic ? 0f : _mass;
 
         BulletSimAPI.SetObjectProperties(_scene.WorldID, LocalID, IsStatic, IsSolid, SubscribedEvents(), mass);
+         */
+        BulletSimAPI.RemoveObjectFromWorld2(Scene.World.Ptr, BSBody.Ptr);
+
+        // Set up the object physicalness (does gravity and collisions move this object)
+        MakeDynamic(IsStatic);
+
+        // Make solid or not (do things bounce off or pass through this object)
+        MakeSolid(IsSolid);
+
+        // Arrange for collisions events if the simulator wants them
+        EnableCollisions(SubscribedEvents());
+
+        BulletSimAPI.AddObjectToWorld2(Scene.World.Ptr, BSBody.Ptr);
 
-        // recompute any linkset parameters
-        _linkset.Refresh(this);
+        // Recompute any linkset parameters.
+        // When going from non-physical to physical, this re-enables the constraints that
+        //     had been automatically disabled when the mass was set to zero.
+        Linkset.Refresh(this);
 
-        CollisionFlags cf = BulletSimAPI.GetCollisionFlags2(Body.Ptr);
-        // DetailLog("{0},BSPrim.SetObjectDynamic,taint,static={1},solid={2},mass={3}, cf={4}", LocalID, IsStatic, IsSolid, mass, cf);
+        DetailLog("{0},BSPrim.UpdatePhysicalParameters,taint,static={1},solid={2},mass={3}, cf={4}", 
+                        LocalID, IsStatic, IsSolid, _mass, m_currentCollisionFlags);
+    }
+
+    // "Making dynamic" means changing to and from static.
+    // When static, gravity does not effect the object and it is fixed in space.
+    // When dynamic, the object can fall and be pushed by others.
+    // This is independent of its 'solidness' which controls what passes through
+    //    this object and what interacts with it.
+    private void MakeDynamic(bool makeStatic)
+    {
+        if (makeStatic)
+        {
+            // Become a Bullet 'static' object type
+            m_currentCollisionFlags = BulletSimAPI.AddToCollisionFlags2(BSBody.Ptr, CollisionFlags.CF_STATIC_OBJECT);
+            // Stop all movement
+            BulletSimAPI.ClearAllForces2(BSBody.Ptr);
+            // Center of mass is at the center of the object
+            BulletSimAPI.SetCenterOfMassByPosRot2(Linkset.LinksetRoot.BSBody.Ptr, _position, _orientation);
+            // Mass is zero which disables a bunch of physics stuff in Bullet
+            BulletSimAPI.SetMassProps2(BSBody.Ptr, 0f, OMV.Vector3.Zero);
+            // There is no inertia in a static object
+            BulletSimAPI.UpdateInertiaTensor2(BSBody.Ptr);
+            // There can be special things needed for implementing linksets
+            Linkset.MakeStatic(this);
+            // The activation state is 'sleeping' so Bullet will not try to act on it
+            BulletSimAPI.ForceActivationState2(BSBody.Ptr, ActivationState.ISLAND_SLEEPING);
+        }
+        else
+        {
+            // Not a Bullet static object
+            m_currentCollisionFlags = BulletSimAPI.RemoveFromCollisionFlags2(BSBody.Ptr, CollisionFlags.CF_STATIC_OBJECT);
+
+            // Set various physical properties so internal things will get computed correctly as they are set
+            BulletSimAPI.SetFriction2(BSBody.Ptr, Scene.Params.defaultFriction);
+            BulletSimAPI.SetRestitution2(BSBody.Ptr, Scene.Params.defaultRestitution);
+            // per http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=3382
+            BulletSimAPI.SetInterpolationLinearVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
+            BulletSimAPI.SetInterpolationAngularVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
+            BulletSimAPI.SetInterpolationVelocity2(BSBody.Ptr, OMV.Vector3.Zero, OMV.Vector3.Zero);
+
+            // A dynamic object has mass
+            IntPtr collisionShapePtr = BulletSimAPI.GetCollisionShape2(BSBody.Ptr);
+            OMV.Vector3 inertia = BulletSimAPI.CalculateLocalInertia2(collisionShapePtr, Linkset.LinksetMass);
+            BulletSimAPI.SetMassProps2(BSBody.Ptr, _mass, inertia);
+            // Inertia is based on our new mass
+            BulletSimAPI.UpdateInertiaTensor2(BSBody.Ptr);
+
+            // Various values for simulation limits
+            BulletSimAPI.SetDamping2(BSBody.Ptr, Scene.Params.linearDamping, Scene.Params.angularDamping);
+            BulletSimAPI.SetDeactivationTime2(BSBody.Ptr, Scene.Params.deactivationTime);
+            BulletSimAPI.SetSleepingThresholds2(BSBody.Ptr, Scene.Params.linearSleepingThreshold, Scene.Params.angularSleepingThreshold);
+            BulletSimAPI.SetContactProcessingThreshold2(BSBody.Ptr, Scene.Params.contactProcessingThreshold);
+
+            // There can be special things needed for implementing linksets
+            Linkset.MakeDynamic(this);
+
+            // Force activation of the object so Bullet will act on it.
+            BulletSimAPI.Activate2(BSBody.Ptr, true);
+        }
+    }
+
+    // "Making solid" means that other object will not pass through this object.
+    private void MakeSolid(bool makeSolid)
+    {
+        if (makeSolid)
+        {
+            // Easy in Bullet -- just remove the object flag that controls collision response
+            m_currentCollisionFlags = BulletSimAPI.RemoveFromCollisionFlags2(BSBody.Ptr, CollisionFlags.CF_NO_CONTACT_RESPONSE);
+        }
+        else
+        {
+            m_currentCollisionFlags = BulletSimAPI.AddToCollisionFlags2(BSBody.Ptr, CollisionFlags.CF_NO_CONTACT_RESPONSE);
+        }
+    }
+
+    // Turn on or off the flag controlling whether collision events are returned to the simulator.
+    private void EnableCollisions(bool wantsCollisionEvents)
+    {
+        if (wantsCollisionEvents)
+        {
+            m_currentCollisionFlags = BulletSimAPI.AddToCollisionFlags2(BSBody.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
+        }
+        else
+        {
+            m_currentCollisionFlags = BulletSimAPI.RemoveFromCollisionFlags2(BSBody.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
+        }
     }
 
     // prims don't fly
     public override bool Flying { 
         get { return _flying; } 
-        set { _flying = value; } 
+        set {
+            _flying = value;
+        } 
     }
     public override bool SetAlwaysRun { 
         get { return _setAlwaysRun; } 
@@ -558,8 +658,8 @@ public sealed class BSPrim : PhysicsActor
             // m_log.DebugFormat("{0}: RotationalVelocity={1}", LogHeader, _rotationalVelocity);
             _scene.TaintedObject("BSPrim.setRotationalVelocity", delegate()
             {
-                // DetailLog("{0},BSPrim.SetRotationalVel,taint,rotvel={1}", LocalID, _rotationalVelocity);
-                BulletSimAPI.SetObjectAngularVelocity(_scene.WorldID, LocalID, _rotationalVelocity);
+                DetailLog("{0},BSPrim.SetRotationalVel,taint,rotvel={1}", LocalID, _rotationalVelocity);
+                BulletSimAPI.SetAngularVelocity2(BSBody.Ptr, _rotationalVelocity);
             });
         } 
     }
@@ -575,8 +675,11 @@ public sealed class BSPrim : PhysicsActor
             _buoyancy = value;
             _scene.TaintedObject("BSPrim.setBuoyancy", delegate()
             {
-                // DetailLog("{0},BSPrim.SetBuoyancy,taint,buoy={1}", LocalID, _buoyancy);
-                BulletSimAPI.SetObjectBuoyancy(_scene.WorldID, _localID, _buoyancy);
+                DetailLog("{0},BSPrim.SetBuoyancy,taint,buoy={1}", LocalID, _buoyancy);
+                // Buoyancy is faked by changing the gravity applied to the object
+                float grav = Scene.Params.gravity * (1f - _buoyancy);
+                BulletSimAPI.SetGravity2(BSBody.Ptr, new OMV.Vector3(0f, 0f, grav));
+                // BulletSimAPI.SetObjectBuoyancy(_scene.WorldID, _localID, _buoyancy);
             });
         } 
     }
@@ -624,7 +727,7 @@ public sealed class BSPrim : PhysicsActor
         }
         else
         {
-            m_log.WarnFormat("{0}: Got a NaN force applied to a Character", LogHeader);
+            m_log.WarnFormat("{0}: Got a NaN force applied to a prim. LocalID={1}", LogHeader, LocalID);
             return;
         }
         _scene.TaintedObject("BSPrim.AddForce", delegate()
@@ -638,17 +741,18 @@ public sealed class BSPrim : PhysicsActor
                 }
                 m_accumulatedForces.Clear();
             }
-            // DetailLog("{0},BSPrim.AddObjectForce,taint,force={1}", LocalID, _force);
-            BulletSimAPI.AddObjectForce2(Body.Ptr, fSum);
+            DetailLog("{0},BSPrim.AddObjectForce,taint,force={1}", LocalID, fSum);
+            // For unknown reasons, "ApplyCentralForce" adds this force to the total force on the object.
+            BulletSimAPI.ApplyCentralForce2(BSBody.Ptr, fSum);
         });
     }
 
     public override void AddAngularForce(OMV.Vector3 force, bool pushforce) { 
-        // DetailLog("{0},BSPrim.AddAngularForce,call,angForce={1},push={2}", LocalID, force, pushforce);
+        DetailLog("{0},BSPrim.AddAngularForce,call,angForce={1},push={2}", LocalID, force, pushforce);
         // m_log.DebugFormat("{0}: AddAngularForce. f={1}, push={2}", LogHeader, force, pushforce);
     }
     public override void SetMomentum(OMV.Vector3 momentum) { 
-        // DetailLog("{0},BSPrim.SetMomentum,call,mom={1}", LocalID, momentum);
+        DetailLog("{0},BSPrim.SetMomentum,call,mom={1}", LocalID, momentum);
     }
     public override void SubscribeEvents(int ms) { 
         _subscribedEventsMs = ms;
@@ -659,7 +763,7 @@ public sealed class BSPrim : PhysicsActor
 
             Scene.TaintedObject("BSPrim.SubscribeEvents", delegate()
             {
-                BulletSimAPI.AddToCollisionFlags2(Body.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
+                m_currentCollisionFlags = BulletSimAPI.AddToCollisionFlags2(BSBody.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
             });
         }
     }
@@ -667,7 +771,7 @@ public sealed class BSPrim : PhysicsActor
         _subscribedEventsMs = 0;
         Scene.TaintedObject("BSPrim.UnSubscribeEvents", delegate()
         {
-            BulletSimAPI.RemoveFromCollisionFlags2(Body.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
+            m_currentCollisionFlags = BulletSimAPI.RemoveFromCollisionFlags2(BSBody.Ptr, CollisionFlags.BS_SUBSCRIBE_COLLISION_EVENTS);
         });
     }
     public override bool SubscribedEvents() { 
@@ -974,39 +1078,47 @@ public sealed class BSPrim : PhysicsActor
     }// end CalculateMass
     #endregion Mass Calculation
 
-    // Create the geometry information in Bullet for later use
-    // The objects needs a hull if it's physical otherwise a mesh is enough
-    // No locking here because this is done when we know physics is not simulating
-    // if 'forceRebuild' is true, the geometry is rebuilt. Otherwise a previously built version is used
-    // Returns 'true' if the geometry was rebuilt
+    // Create the geometry information in Bullet for later use.
+    // The objects needs a hull if it's physical otherwise a mesh is enough.
+    // No locking here because this is done when we know physics is not simulating.
+    // 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)
     {
-        // the mesher thought this was too simple to mesh. Use a native Bullet collision shape.
         bool ret = false;
-        if (!_scene.NeedsMeshing(_pbs))
+        bool haveShape = false;
+
+        // If the prim attributes are simple, this could be a simple Bullet native shape
+        if ((_pbs.SculptEntry && !Scene.ShouldMeshSculptedPrim)
+                || (_pbs.ProfileBegin == 0 && _pbs.ProfileEnd == 0
+                    && _pbs.ProfileHollow == 0
+                    && _pbs.PathTwist == 0 && _pbs.PathTwistBegin == 0
+                    && _pbs.PathBegin == 0 && _pbs.PathEnd == 0
+                    && _pbs.PathTaperX == 0 && _pbs.PathTaperY == 0
+                    && _pbs.PathScaleX == 100 && _pbs.PathScaleY == 100
+                    && _pbs.PathShearX == 0 && _pbs.PathShearY == 0) )
         {
             if (_pbs.ProfileShape == ProfileShape.HalfCircle && _pbs.PathCurve == (byte)Extrusion.Curve1)
             {
-                // if (_size.X == _size.Y && _size.Y == _size.Z && _size.X == _size.Z)
-                // {
-                    // m_log.DebugFormat("{0}: CreateGeom: Defaulting to sphere of size {1}", LogHeader, _size);
-                    if (forceRebuild || (_shapeType != ShapeData.PhysicsShapeType.SHAPE_SPHERE))
-                    {
-                        // DetailLog("{0},BSPrim.CreateGeom,sphere (force={1}", LocalID, forceRebuild);
-                        _shapeType = ShapeData.PhysicsShapeType.SHAPE_SPHERE;
-                        // Bullet native objects are scaled by the Bullet engine so pass the size in
-                        _scale = _size;
-                        // TODO: do we need to check for and destroy a mesh or hull that might have been left from before?
-                        ret = true;
-                    }
-                // }
+                haveShape = true;
+                if (forceRebuild || (_shapeType != ShapeData.PhysicsShapeType.SHAPE_SPHERE))
+                {
+                    DetailLog("{0},BSPrim.CreateGeom,sphere (force={1}", LocalID, forceRebuild);
+                    _shapeType = ShapeData.PhysicsShapeType.SHAPE_SPHERE;
+                    // Bullet native objects are scaled by the Bullet engine so pass the size in
+                    _scale = _size;
+                    // TODO: do we need to check for and destroy a mesh or hull that might have been left from before?
+                    ret = true;
+                }
             }
             else
             {
                 // m_log.DebugFormat("{0}: CreateGeom: Defaulting to box. lid={1}, type={2}, size={3}", LogHeader, LocalID, _shapeType, _size);
+                haveShape = true;
                 if (forceRebuild || (_shapeType != ShapeData.PhysicsShapeType.SHAPE_BOX))
                 {
-                    // DetailLog("{0},BSPrim.CreateGeom,box (force={1})", LocalID, forceRebuild);
+                    DetailLog("{0},BSPrim.CreateGeom,box (force={1})", LocalID, forceRebuild);
                     _shapeType = ShapeData.PhysicsShapeType.SHAPE_BOX;
                     _scale = _size;
                     // TODO: do we need to check for and destroy a mesh or hull that might have been left from before?
@@ -1014,16 +1126,16 @@ public sealed class BSPrim : PhysicsActor
                 }
             }
         }
-        else
+        // If a simple shape isn't happening, create a mesh and possibly a hull
+        if (!haveShape)
         {
             if (IsPhysical)
             {
                 if (forceRebuild || _hullKey == 0)
                 {
                     // physical objects require a hull for interaction.
-                    // This will create the mesh if it doesn't already exist
-                    CreateGeomHull();
-                    ret = true;
+                    // This also creates the mesh if it doesn't already exist
+                    ret = CreateGeomHull();
                 }
             }
             else
@@ -1031,8 +1143,7 @@ public sealed class BSPrim : PhysicsActor
                 if (forceRebuild || _meshKey == 0)
                 {
                     // Static (non-physical) objects only need a mesh for bumping into
-                    CreateGeomMesh();
-                    ret = true;
+                    ret = CreateGeomMesh();
                 }
             }
         }
@@ -1040,21 +1151,30 @@ public sealed class BSPrim : PhysicsActor
     }
 
     // No locking here because this is done when we know physics is not simulating
-    private void CreateGeomMesh()
+    // Returns 'true' of a mesh was actually rebuild (we could also have one of these specs).
+    // Called at taint-time!
+    private bool CreateGeomMesh()
     {
-        float lod = _pbs.SculptEntry ? _scene.SculptLOD : _scene.MeshLOD;
+        // level of detail based on size and type of the object
+        float lod = _scene.MeshLOD;
+        if (_pbs.SculptEntry) 
+            lod = _scene.SculptLOD;
+        float maxAxis = Math.Max(_size.X, Math.Max(_size.Y, _size.Z));
+        if (maxAxis > _scene.MeshMegaPrimThreshold) 
+            lod = _scene.MeshMegaPrimLOD;
+
         ulong newMeshKey = (ulong)_pbs.GetMeshKey(_size, lod);
         // m_log.DebugFormat("{0}: CreateGeomMesh: lID={1}, oldKey={2}, newKey={3}", LogHeader, _localID, _meshKey, newMeshKey);
 
         // if this new shape is the same as last time, don't recreate the mesh
-        if (_meshKey == newMeshKey) return;
+        if (_meshKey == newMeshKey) return false;
 
-        // DetailLog("{0},BSPrim.CreateGeomMesh,create,key={1}", LocalID, newMeshKey);
+        DetailLog("{0},BSPrim.CreateGeomMesh,create,key={1}", LocalID, newMeshKey);
         // Since we're recreating new, get rid of any previously generated shape
         if (_meshKey != 0)
         {
             // m_log.DebugFormat("{0}: CreateGeom: deleting old mesh. lID={1}, Key={2}", LogHeader, _localID, _meshKey);
-            // DetailLog("{0},BSPrim.CreateGeomMesh,deleteOld,key={1}", LocalID, _meshKey);
+            DetailLog("{0},BSPrim.CreateGeomMesh,deleteOld,key={1}", LocalID, _meshKey);
             BulletSimAPI.DestroyMesh(_scene.WorldID, _meshKey);
             _mesh = null;
             _meshKey = 0;
@@ -1084,27 +1204,27 @@ public sealed class BSPrim : PhysicsActor
         _shapeType = ShapeData.PhysicsShapeType.SHAPE_MESH;
         // meshes are already scaled by the meshmerizer
         _scale = new OMV.Vector3(1f, 1f, 1f);
-        // DetailLog("{0},BSPrim.CreateGeomMesh,done", LocalID);
-        return;
+        return true;
     }
 
     // No locking here because this is done when we know physics is not simulating
-    private void CreateGeomHull()
+    // Returns 'true' of a mesh was actually rebuild (we could also have one of these specs).
+    private bool CreateGeomHull()
     {
         float lod = _pbs.SculptEntry ? _scene.SculptLOD : _scene.MeshLOD;
         ulong newHullKey = (ulong)_pbs.GetMeshKey(_size, lod);
         // m_log.DebugFormat("{0}: CreateGeomHull: lID={1}, oldKey={2}, newKey={3}", LogHeader, _localID, _hullKey, newHullKey);
 
         // if the hull hasn't changed, don't rebuild it
-        if (newHullKey == _hullKey) return;
+        if (newHullKey == _hullKey) return false;
 
-        // DetailLog("{0},BSPrim.CreateGeomHull,create,oldKey={1},newKey={2}", LocalID, _hullKey, newHullKey);
+        DetailLog("{0},BSPrim.CreateGeomHull,create,oldKey={1},newKey={2}", LocalID, _hullKey, newHullKey);
         
         // Since we're recreating new, get rid of any previously generated shape
         if (_hullKey != 0)
         {
             // m_log.DebugFormat("{0}: CreateGeom: deleting old hull. Key={1}", LogHeader, _hullKey);
-            // DetailLog("{0},BSPrim.CreateGeomHull,deleteOldHull,key={1}", LocalID, _hullKey);
+            DetailLog("{0},BSPrim.CreateGeomHull,deleteOldHull,key={1}", LocalID, _hullKey);
             BulletSimAPI.DestroyHull(_scene.WorldID, _hullKey);
             _hullKey = 0;
         }
@@ -1198,8 +1318,8 @@ public sealed class BSPrim : PhysicsActor
         _shapeType = ShapeData.PhysicsShapeType.SHAPE_HULL;
         // meshes are already scaled by the meshmerizer
         _scale = new OMV.Vector3(1f, 1f, 1f);
-        // DetailLog("{0},BSPrim.CreateGeomHull,done", LocalID);
-        return;
+        DetailLog("{0},BSPrim.CreateGeomHull,done", LocalID);
+        return true;
     }
 
     // Callback from convex hull creater with a newly created hull.
@@ -1210,6 +1330,19 @@ public sealed class BSPrim : PhysicsActor
         return;
     }
 
+    private void VerifyCorrectPhysicalShape()
+    {
+        if (!IsStatic)
+        {
+            // if not static, it will need a hull to efficiently collide with things
+            if (_hullKey == 0)
+            {
+                CreateGeomAndObject(false);
+            }
+
+        }
+    }
+
     // Create an object in Bullet if it has not already been created
     // No locking here because this is done when the physics engine is not simulating
     // Returns 'true' if an object was actually created.
@@ -1223,8 +1356,9 @@ public sealed class BSPrim : PhysicsActor
         // m_log.DebugFormat("{0}: CreateObject: lID={1}, shape={2}", LogHeader, _localID, shape.Type);
         bool ret = BulletSimAPI.CreateObject(_scene.WorldID, shape);
 
-        // the CreateObject() may have recreated the rigid body. Make sure we have the latest.
-        Body = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(_scene.World.Ptr, LocalID));
+        // the CreateObject() may have recreated the rigid body. Make sure we have the latest address.
+        BSBody = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(_scene.World.Ptr, LocalID));
+        BSShape = new BulletShape(BulletSimAPI.GetCollisionShape2(BSBody.Ptr));
 
         return ret;
     }
@@ -1248,15 +1382,20 @@ public sealed class BSPrim : PhysicsActor
         shape.Static = _isPhysical ? ShapeData.numericFalse : ShapeData.numericTrue;
     }
 
-
     // Rebuild the geometry and object.
     // This is called when the shape changes so we need to recreate the mesh/hull.
     // No locking here because this is done when the physics engine is not simulating
-    private void RecreateGeomAndObject()
+    private void CreateGeomAndObject(bool forceRebuild)
     {
-        // m_log.DebugFormat("{0}: RecreateGeomAndObject. lID={1}", LogHeader, _localID);
-        if (CreateGeom(true))
+        // m_log.DebugFormat("{0}: CreateGeomAndObject. lID={1}, force={2}", LogHeader, _localID, forceRebuild);
+        // Create the geometry that will make up the object
+        if (CreateGeom(forceRebuild))
+        {
+            // Create the object and place it into the world
             CreateObject();
+            // Make sure the properties are set on the new object
+            UpdatePhysicalParameters();
+        }
         return;
     }
 
@@ -1277,7 +1416,7 @@ public sealed class BSPrim : PhysicsActor
     const float ACCELERATION_TOLERANCE = 0.01f;
     const float ROTATIONAL_VELOCITY_TOLERANCE = 0.01f;
 
-    public void UpdateProperties(EntityProperties entprop)
+    public override void UpdateProperties(EntityProperties entprop)
     {
         /*
         UpdatedProperties changed = 0;
@@ -1325,7 +1464,7 @@ public sealed class BSPrim : PhysicsActor
         // Don't check for damping here -- it's done in BulletSim and SceneObjectPart.
 
         // Updates only for individual prims and for the root object of a linkset.
-        if (_linkset.IsRoot(this))
+        if (Linkset.IsRoot(this))
         {
             // Assign to the local variables so the normal set action does not happen
             _position = entprop.Position;
@@ -1334,17 +1473,17 @@ public sealed class BSPrim : PhysicsActor
             _acceleration = entprop.Acceleration;
             _rotationalVelocity = entprop.RotationalVelocity;
 
-            // m_log.DebugFormat("{0}: RequestTerseUpdate. id={1}, ch={2}, pos={3}, rot={4}, vel={5}, acc={6}, rvel={7}", 
-            //         LogHeader, LocalID, changed, _position, _orientation, _velocity, _acceleration, _rotationalVelocity);
-            // DetailLog("{0},BSPrim.UpdateProperties,call,pos={1},orient={2},vel={3},accel={4},rotVel={5}",
-            //         LocalID, _position, _orientation, _velocity, _acceleration, _rotationalVelocity);
+            DetailLog("{0},BSPrim.UpdateProperties,call,pos={1},orient={2},vel={3},accel={4},rotVel={5}",
+                    LocalID, _position, _orientation, _velocity, _acceleration, _rotationalVelocity);
+
+            // BulletSimAPI.DumpRigidBody2(Scene.World.Ptr, BSBody.Ptr);
 
             base.RequestPhysicsterseUpdate();
         }
             /*
         else
         {
-            // For debugging, we also report the movement of children
+            // For debugging, we can also report the movement of children
             DetailLog("{0},BSPrim.UpdateProperties,child,pos={1},orient={2},vel={3},accel={4},rotVel={5}",
                     LocalID, entprop.Position, entprop.Rotation, entprop.Velocity, 
                     entprop.Acceleration, entprop.RotationalVelocity);
@@ -1353,36 +1492,45 @@ public sealed class BSPrim : PhysicsActor
     }
 
     // I've collided with something
+    // Called at taint time from within the Step() function
     CollisionEventUpdate collisionCollection;
-    public void Collide(uint collidingWith, ActorTypes type, OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
+    public override bool Collide(uint collidingWith, BSPhysObject collidee, OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
     {
-        // m_log.DebugFormat("{0}: Collide: ms={1}, id={2}, with={3}", LogHeader, _subscribedEventsMs, LocalID, collidingWith);
+        bool ret = false;
 
         // The following lines make IsColliding() and IsCollidingGround() work
-        _collidingStep = _scene.SimulationStep;
-        if (collidingWith == BSScene.TERRAIN_ID || collidingWith == BSScene.GROUNDPLANE_ID)
+        _collidingStep = Scene.SimulationStep;
+        if (collidingWith <= Scene.TerrainManager.HighestTerrainID)
         {
-            _collidingGroundStep = _scene.SimulationStep;
+            _collidingGroundStep = Scene.SimulationStep;
         }
 
         // DetailLog("{0},BSPrim.Collison,call,with={1}", LocalID, collidingWith);
 
-        // if someone is subscribed to collision events....
-        if (_subscribedEventsMs != 0) {
+        // prims in the same linkset cannot collide with each other
+        if (collidee != null && (this.Linkset.LinksetID == collidee.Linkset.LinksetID))
+        {
+            return ret;
+        }
+
+        // if someone has subscribed for collision events....
+        if (SubscribedEvents()) {
             // throttle the collisions to the number of milliseconds specified in the subscription
-            int nowTime = _scene.SimulationNowTime;
+            int nowTime = Scene.SimulationNowTime;
             if (nowTime >= _nextCollisionOkTime) {
                 _nextCollisionOkTime = nowTime + _subscribedEventsMs;
 
                 if (collisionCollection == null)
                     collisionCollection = new CollisionEventUpdate();
                 collisionCollection.AddCollider(collidingWith, new ContactPoint(contactPoint, contactNormal, pentrationDepth));
+                ret = true;
             }
         }
+        return ret;
     }
 
     // The scene is telling us it's time to pass our collected collisions into the simulator
-    public void SendCollisions()
+    public override void SendCollisions()
     {
         if (collisionCollection != null && collisionCollection.Count > 0)
         {