1 files changed, 1267 insertions, 0 deletions
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
new file mode 100644
index 0000000..cc414e9
--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -0,0 +1,1267 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyrightD
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+using System;
+using System.Reflection;
+using System.Collections.Generic;
+using System.Xml;
+using log4net;
+using OMV = OpenMetaverse;
+using OpenSim.Framework;
+using OpenSim.Region.Physics.Manager;
+using OpenSim.Region.Physics.ConvexDecompositionDotNet;
+namespace OpenSim.Region.Physics.BulletSPlugin
+{
+    [Serializable]
+public sealed class BSPrim : PhysicsActor
+{
+    private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+    private static readonly string LogHeader = "[BULLETS PRIM]";
+    private IMesh _mesh;
+    private PrimitiveBaseShape _pbs;
+    private ShapeData.PhysicsShapeType _shapeType;
+    private ulong _hullKey;
+    private List<ConvexResult> _hulls;
+    private BSScene _scene;
+    private String _avName;
+    private uint _localID = 0;
+    private OMV.Vector3 _size;
+    private OMV.Vector3 _scale;
+    private bool _stopped;
+    private bool _grabbed;
+    private bool _isSelected;
+    private bool _isVolumeDetect;
+    private OMV.Vector3 _position;
+    private float _mass;
+    private float _density;
+    private OMV.Vector3 _force;
+    private OMV.Vector3 _velocity;
+    private OMV.Vector3 _torque;
+    private float _collisionScore;
+    private OMV.Vector3 _acceleration;
+    private OMV.Quaternion _orientation;
+    private int _physicsActorType;
+    private bool _isPhysical;
+    private bool _flying;
+    private float _friction;
+    private float _restitution;
+    private bool _setAlwaysRun;
+    private bool _throttleUpdates;
+    private bool _isColliding;
+    private bool _collidingGround;
+    private bool _collidingObj;
+    private bool _floatOnWater;
+    private OMV.Vector3 _rotationalVelocity;
+    private bool _kinematic;
+    private float _buoyancy;
+    private OMV.Vector3 _angularVelocity;
+    private List<BSPrim> _childrenPrims;
+    private BSPrim _parentPrim;
+    private int _subscribedEventsMs = 0;
+    private int _lastCollisionTime = 0;
+    long _collidingStep;
+    long _collidingGroundStep;
+    private BSDynamics _vehicle;
+    private OMV.Vector3 _PIDTarget;
+    private bool _usePID;
+    private float _PIDTau;
+    private bool _useHoverPID;
+    private float _PIDHoverHeight;
+    private PIDHoverType _PIDHoverType;
+    private float _PIDHoverTao;
+    public BSPrim(uint localID, String primName, BSScene parent_scene, OMV.Vector3 pos, OMV.Vector3 size,
+                       OMV.Quaternion rotation, PrimitiveBaseShape pbs, bool pisPhysical)
+    {
+        // m_log.DebugFormat("{0}: BSPrim creation of {1}, id={2}", LogHeader, primName, localID);
+        _localID = localID;
+        _avName = primName;
+        _scene = parent_scene;
+        _position = pos;
+        _size = size;
+        _scale = new OMV.Vector3(1f, 1f, 1f);   // the scale will be set by CreateGeom depending on object type
+        _orientation = rotation;
+        _buoyancy = 1f;
+        _velocity = OMV.Vector3.Zero;
+        _rotationalVelocity = OMV.Vector3.Zero;
+        _angularVelocity = OMV.Vector3.Zero;
+        _hullKey = 0;
+        _pbs = pbs;
+        _isPhysical = pisPhysical;
+        _isVolumeDetect = false;
+        _subscribedEventsMs = 0;
+        _friction = _scene.Params.defaultFriction; // TODO: compute based on object material
+        _density = _scene.Params.defaultDensity; // TODO: compute based on object material
+        _restitution = _scene.Params.defaultRestitution;
+        _parentPrim = null;     // not a child or a parent
+        _vehicle = new BSDynamics(this);    // add vehicleness
+        _childrenPrims = new List<BSPrim>();
+        if (_isPhysical)
+            _mass = CalculateMass();
+        else
+            _mass = 0f;
+        // do the actual object creation at taint time
+        _scene.TaintedObject(delegate()
+        {
+            RecreateGeomAndObject();
+        });
+    }
+    // called when this prim is being destroyed and we should free all the resources
+    public void Destroy()
+    {
+        // m_log.DebugFormat("{0}: Destroy", LogHeader);
+        // Undo any vehicle properties
+        _vehicle.ProcessTypeChange(Vehicle.TYPE_NONE);
+        _scene.RemoveVehiclePrim(this);     // just to make sure
+        _scene.TaintedObject(delegate()
+        {
+            BulletSimAPI.DestroyObject(_scene.WorldID, _localID);
+        });
+    }
+    
+    public override bool Stopped { 
+        get { return _stopped; } 
+    }
+    public override OMV.Vector3 Size { 
+        get { return _size; } 
+        set {
+            _size = value;
+            _scene.TaintedObject(delegate()
+            {
+                if (_isPhysical) _mass = CalculateMass();   // changing size changes the mass
+                BulletSimAPI.SetObjectScaleMass(_scene.WorldID, _localID, _scale, _mass, _isPhysical);
+                RecreateGeomAndObject();
+            });
+        } 
+    }
+    public override PrimitiveBaseShape Shape { 
+        set {
+            _pbs = value;
+            _scene.TaintedObject(delegate()
+            {
+                if (_isPhysical) _mass = CalculateMass();   // changing the shape changes the mass
+                RecreateGeomAndObject();
+            });
+        } 
+    }
+    public override uint LocalID { 
+        set { _localID = value; }
+        get { return _localID; }
+    }
+    public override bool Grabbed { 
+        set { _grabbed = value; 
+        } 
+    }
+    public override bool Selected { 
+        set {
+            _isSelected = value;
+            _scene.TaintedObject(delegate()
+            {
+                SetObjectDynamic();
+            });
+        } 
+    }
+    public override void CrossingFailure() { return; }
+    // link me to the specified parent
+    public override void link(PhysicsActor obj) {
+        BSPrim parent = (BSPrim)obj;
+        // m_log.DebugFormat("{0}: link {1}/{2} to {3}", LogHeader, _avName, _localID, obj.LocalID);
+        // TODO: decide if this parent checking needs to happen at taint time
+        if (_parentPrim == null)
+        {
+            if (parent != null)
+            {
+                // I don't have a parent so I am joining a linkset
+                parent.AddChildToLinkset(this);
+            }
+        }
+        else
+        {
+            // I already have a parent, is parenting changing?
+            if (parent != _parentPrim)
+            {
+                if (parent == null)
+                {
+                    // we are being removed from a linkset
+                    _parentPrim.RemoveChildFromLinkset(this);
+                }
+                else
+                {
+                    // asking to reparent a prim should not happen
+                    m_log.ErrorFormat("{0}: Reparenting a prim. ", LogHeader);
+                }
+            }
+        }
+        return; 
+    }
+    // delink me from my linkset
+    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
+        // m_log.DebugFormat("{0}: delink {1}/{2}", LogHeader, _avName, _localID);
+        if (_parentPrim != null)
+        {
+            _parentPrim.RemoveChildFromLinkset(this);
+        }
+        return; 
+    }
+    // I am the root of a linkset and a new child is being added
+    public void AddChildToLinkset(BSPrim pchild)
+    {
+        BSPrim child = pchild;
+        _scene.TaintedObject(delegate()
+        {
+            if (!_childrenPrims.Contains(child))
+            {
+                _childrenPrims.Add(child);
+                child.ParentPrim = this;    // the child has gained a parent
+                RecreateGeomAndObject();    // rebuild my shape with the new child added
+            }
+        });
+        return;
+    }
+    // I am the root of a linkset and one of my children is being removed.
+    // Safe to call even if the child is not really in my linkset.
+    public void RemoveChildFromLinkset(BSPrim pchild)
+    {
+        BSPrim child = pchild;
+        _scene.TaintedObject(delegate()
+        {
+            if (_childrenPrims.Contains(child))
+            {
+                BulletSimAPI.RemoveConstraint(_scene.WorldID, child.LocalID, this.LocalID);
+                _childrenPrims.Remove(child);
+                child.ParentPrim = null;    // the child has lost its parent
+                RecreateGeomAndObject();    // rebuild my shape with the child removed
+            }
+            else
+            {
+                m_log.ErrorFormat("{0}: Asked to remove child from linkset that was not in linkset");
+            }
+        });
+        return;
+    }
+    public BSPrim ParentPrim
+    {
+        set { _parentPrim = value; }
+    }
+    public ulong HullKey
+    {
+        get { return _hullKey; }
+    }
+    // return true if we are the root of a linkset (there are children to manage)
+    public bool IsRootOfLinkset
+    {
+        get { return (_parentPrim == null && _childrenPrims.Count != 0); }
+    }
+    // Set motion values to zero.
+    // Do it to the properties so the values get set in the physics engine.
+    // Push the setting of the values to the viewer.
+    private void ZeroMotion()
+    {
+        Velocity = OMV.Vector3.Zero;
+        _acceleration = OMV.Vector3.Zero;
+        RotationalVelocity = OMV.Vector3.Zero;
+        base.RequestPhysicsterseUpdate();
+    }
+    public override void LockAngularMotion(OMV.Vector3 axis) { return; }
+    public override OMV.Vector3 Position { 
+        get { 
+            // don't do the following GetObjectPosition because this function is called a zillion times
+            // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
+            return _position; 
+        } 
+        set {
+            _position = value;
+            _scene.TaintedObject(delegate()
+            {
+                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+                // m_log.DebugFormat("{0}: setPosition: id={1}, position={2}", LogHeader, _localID, _position);
+            });
+        } 
+    }
+    public override float Mass { 
+        get { return _mass; } 
+    }
+    public override OMV.Vector3 Force { 
+        get { return _force; } 
+        set {
+            _force = value;
+            _scene.TaintedObject(delegate()
+            {
+                BulletSimAPI.SetObjectForce(_scene.WorldID, _localID, _force);
+            });
+        } 
+    }
+    public override int VehicleType { 
+        get {
+            return (int)_vehicle.Type;   // if we are a vehicle, return that type
+        } 
+        set {
+            Vehicle type = (Vehicle)value;
+            _vehicle.ProcessTypeChange(type);
+            _scene.TaintedObject(delegate()
+            {
+                if (type == Vehicle.TYPE_NONE)
+                {
+                    _scene.RemoveVehiclePrim(this);
+                }
+                else
+                {
+                    // make it so the scene will call us each tick to do vehicle things
+                    _scene.AddVehiclePrim(this);
+                }
+                return;
+            });
+        } 
+    }
+    public override void VehicleFloatParam(int param, float value) 
+    {
+        _vehicle.ProcessFloatVehicleParam((Vehicle)param, value);
+    }
+    public override void VehicleVectorParam(int param, OMV.Vector3 value) 
+    {
+        _vehicle.ProcessVectorVehicleParam((Vehicle)param, value);
+    }
+    public override void VehicleRotationParam(int param, OMV.Quaternion rotation) 
+    {
+        _vehicle.ProcessRotationVehicleParam((Vehicle)param, rotation);
+    }
+    public override void VehicleFlags(int param, bool remove) 
+    {
+        _vehicle.ProcessVehicleFlags(param, remove);
+    }
+    // Called each simulation step to advance vehicle characteristics
+    public void StepVehicle(float timeStep)
+    {
+        _vehicle.Step(timeStep, _scene);
+    }
+    // Allows the detection of collisions with inherently non-physical prims. see llVolumeDetect for more
+    public override void SetVolumeDetect(int param) {
+        bool newValue = (param != 0);
+        if (_isVolumeDetect != newValue)
+        {
+            _isVolumeDetect = newValue;
+            _scene.TaintedObject(delegate()
+            {
+                SetObjectDynamic();
+            });
+        }
+        return; 
+    }
+    public override OMV.Vector3 GeometricCenter { get { return OMV.Vector3.Zero; } }
+    public override OMV.Vector3 CenterOfMass { get { return OMV.Vector3.Zero; } }
+    public override OMV.Vector3 Velocity { 
+        get { return _velocity; } 
+        set { _velocity = value; 
+            _scene.TaintedObject(delegate()
+            {
+                BulletSimAPI.SetObjectVelocity(_scene.WorldID, LocalID, _velocity);
+            });
+        } 
+    }
+    public override OMV.Vector3 Torque { 
+        get { return _torque; } 
+        set { _torque = value; 
+        } 
+    }
+    public override float CollisionScore { 
+        get { return _collisionScore; } 
+        set { _collisionScore = value; 
+        } 
+    }
+    public override OMV.Vector3 Acceleration { 
+        get { return _acceleration; } 
+    }
+    public override OMV.Quaternion Orientation { 
+        get { return _orientation; } 
+        set {
+            _orientation = value;
+            // m_log.DebugFormat("{0}: set orientation: id={1}, ori={2}", LogHeader, LocalID, _orientation);
+            _scene.TaintedObject(delegate()
+            {
+                // _position = BulletSimAPI.GetObjectPosition(_scene.WorldID, _localID);
+                BulletSimAPI.SetObjectTranslation(_scene.WorldID, _localID, _position, _orientation);
+            });
+        } 
+    }
+    public override int PhysicsActorType { 
+        get { return _physicsActorType; } 
+        set { _physicsActorType = value; 
+        } 
+    }
+    public override bool IsPhysical { 
+        get { return _isPhysical; } 
+        set {
+            _isPhysical = value;
+            _scene.TaintedObject(delegate()
+            {
+                SetObjectDynamic();
+            });
+        } 
+    }
+    // An object is static (does not move) if selected or not physical
+    private bool IsStatic
+    {
+        get { return _isSelected || !IsPhysical; }
+    }
+    // An object is solid if it's not phantom and if it's not doing VolumeDetect
+    private bool IsSolid
+    {
+        get { return !IsPhantom && !_isVolumeDetect; }
+    }
+    // make gravity work if the object is physical and not selected
+    // no locking here because only called when it is safe
+    private void SetObjectDynamic()
+    {
+        // non-physical things work best with a mass of zero
+        _mass = IsStatic ? 0f : CalculateMass();
+        BulletSimAPI.SetObjectProperties(_scene.WorldID, LocalID, IsStatic, IsSolid, SubscribedEvents(), _mass);
+        // m_log.DebugFormat("{0}: ID={1}, SetObjectDynamic: IsStatic={2}, IsSolid={3}, mass={4}", LogHeader, _localID, IsStatic, IsSolid, _mass);
+    }
+    // prims don't fly
+    public override bool Flying { 
+        get { return _flying; } 
+        set { _flying = value; } 
+    }
+    public override bool SetAlwaysRun { 
+        get { return _setAlwaysRun; } 
+        set { _setAlwaysRun = value; } 
+    }
+    public override bool ThrottleUpdates { 
+        get { return _throttleUpdates; } 
+        set { _throttleUpdates = value; } 
+    }
+    public override bool IsColliding {
+        get { return (_collidingStep == _scene.SimulationStep); } 
+        set { _isColliding = value; } 
+    }
+    public override bool CollidingGround {
+        get { return (_collidingGroundStep == _scene.SimulationStep); } 
+        set { _collidingGround = value; } 
+    }
+    public override bool CollidingObj { 
+        get { return _collidingObj; } 
+        set { _collidingObj = value; } 
+    }
+    public bool IsPhantom {
+        get {
+            // SceneObjectPart removes phantom objects from the physics scene
+            // so, although we could implement touching and such, we never
+            // are invoked as a phantom object
+            return false;
+        }
+    }
+    public override bool FloatOnWater { 
+        set { _floatOnWater = value; } 
+    }
+    public override OMV.Vector3 RotationalVelocity { 
+        get { return _rotationalVelocity; } 
+        set { _rotationalVelocity = value; 
+            // m_log.DebugFormat("{0}: RotationalVelocity={1}", LogHeader, _rotationalVelocity);
+            _scene.TaintedObject(delegate()
+            {
+                BulletSimAPI.SetObjectAngularVelocity(_scene.WorldID, LocalID, _rotationalVelocity);
+            });
+        } 
+    }
+    public OMV.Vector3 AngularVelocity { 
+        get { return _angularVelocity; } 
+        set { _angularVelocity = value; } 
+    }
+    public override bool Kinematic { 
+        get { return _kinematic; } 
+        set { _kinematic = value; 
+            // m_log.DebugFormat("{0}: Kinematic={1}", LogHeader, _kinematic);
+        } 
+    }
+    public override float Buoyancy { 
+        get { return _buoyancy; } 
+        set { _buoyancy = value;
+        _scene.TaintedObject(delegate()
+        {
+            BulletSimAPI.SetObjectBuoyancy(_scene.WorldID, _localID, _buoyancy);
+        });
+        } 
+    }
+    // Used for MoveTo
+    public override OMV.Vector3 PIDTarget { 
+        set { _PIDTarget = value; } 
+    }
+    public override bool PIDActive { 
+        set { _usePID = value; } 
+    }
+    public override float PIDTau { 
+        set { _PIDTau = value; } 
+    }
+    // Used for llSetHoverHeight and maybe vehicle height
+    // Hover Height will override MoveTo target's Z
+    public override bool PIDHoverActive { 
+        set { _useHoverPID = value; }
+    }
+    public override float PIDHoverHeight { 
+        set { _PIDHoverHeight = value; }
+    }
+    public override PIDHoverType PIDHoverType { 
+        set { _PIDHoverType = value; }
+    }
+    public override float PIDHoverTau { 
+        set { _PIDHoverTao = value; }
+    }
+    // For RotLookAt
+    public override OMV.Quaternion APIDTarget { set { return; } }
+    public override bool APIDActive { set { return; } }
+    public override float APIDStrength { set { return; } }
+    public override float APIDDamping { set { return; } }
+    public override void AddForce(OMV.Vector3 force, bool pushforce) {
+        if (force.IsFinite())
+        {
+            _force.X += force.X;
+            _force.Y += force.Y;
+            _force.Z += force.Z;
+        }
+        else
+        {
+            m_log.WarnFormat("{0}: Got a NaN force applied to a Character", LogHeader);
+        }
+        _scene.TaintedObject(delegate()
+        {
+            BulletSimAPI.SetObjectForce(_scene.WorldID, _localID, _force);
+        });
+    }
+    public override void AddAngularForce(OMV.Vector3 force, bool pushforce) { 
+        // m_log.DebugFormat("{0}: AddAngularForce. f={1}, push={2}", LogHeader, force, pushforce);
+    }
+    public override void SetMomentum(OMV.Vector3 momentum) { 
+    }
+    public override void SubscribeEvents(int ms) { 
+        _subscribedEventsMs = ms;
+        _lastCollisionTime = Util.EnvironmentTickCount() - _subscribedEventsMs; // make first collision happen
+    }
+    public override void UnSubscribeEvents() { 
+        _subscribedEventsMs = 0;
+    }
+    public override bool SubscribedEvents() { 
+        return (_subscribedEventsMs > 0);
+    }
+    #region Mass Calculation
+    private float CalculateMass()
+    {
+        float volume = _size.X * _size.Y * _size.Z; // default
+        float tmp;
+        float returnMass = 0;
+        float hollowAmount = (float)_pbs.ProfileHollow * 2.0e-5f;
+        float hollowVolume = hollowAmount * hollowAmount; 
+        
+        switch (_pbs.ProfileShape)
+        {
+            case ProfileShape.Square:
+                // default box
+                if (_pbs.PathCurve == (byte)Extrusion.Straight)
+                    {
+                    if (hollowAmount > 0.0)
+                        {
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Square:
+                            case HollowShape.Same:
+                                break;
+                            case HollowShape.Circle:
+                                hollowVolume *= 0.78539816339f;
+                                break;
+                            case HollowShape.Triangle:
+                                hollowVolume *= (0.5f * .5f);
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                else if (_pbs.PathCurve == (byte)Extrusion.Curve1)
+                    {
+                    //a tube 
+                    volume *= 0.78539816339e-2f * (float)(200 - _pbs.PathScaleX);
+                    tmp= 1.0f -2.0e-2f * (float)(200 - _pbs.PathScaleY);
+                    volume -= volume*tmp*tmp;
+                    
+                    if (hollowAmount > 0.0)
+                        {
+                        hollowVolume *= hollowAmount;
+                        
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Square:
+                            case HollowShape.Same:
+                                break;
+                            case HollowShape.Circle:
+                                hollowVolume *= 0.78539816339f;;
+                                break;
+                            case HollowShape.Triangle:
+                                hollowVolume *= 0.5f * 0.5f;
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                break;
+            case ProfileShape.Circle:
+                if (_pbs.PathCurve == (byte)Extrusion.Straight)
+                    {
+                    volume *= 0.78539816339f; // elipse base
+                    if (hollowAmount > 0.0)
+                        {
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Same:
+                            case HollowShape.Circle:
+                                break;
+                            case HollowShape.Square:
+                                hollowVolume *= 0.5f * 2.5984480504799f;
+                                break;
+                            case HollowShape.Triangle:
+                                hollowVolume *= .5f * 1.27323954473516f;
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                else if (_pbs.PathCurve == (byte)Extrusion.Curve1)
+                    {
+                    volume *= 0.61685027506808491367715568749226e-2f * (float)(200 - _pbs.PathScaleX);
+                    tmp = 1.0f - .02f * (float)(200 - _pbs.PathScaleY);
+                    volume *= (1.0f - tmp * tmp);
+                    
+                    if (hollowAmount > 0.0)
+                        {
+                        // calculate the hollow volume by it's shape compared to the prim shape
+                        hollowVolume *= hollowAmount;
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Same:
+                            case HollowShape.Circle:
+                                break;
+                            case HollowShape.Square:
+                                hollowVolume *= 0.5f * 2.5984480504799f;
+                                break;
+                            case HollowShape.Triangle:
+                                hollowVolume *= .5f * 1.27323954473516f;
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                break;
+            case ProfileShape.HalfCircle:
+                if (_pbs.PathCurve == (byte)Extrusion.Curve1)
+                {
+                volume *= 0.52359877559829887307710723054658f;
+                }
+                break;
+            case ProfileShape.EquilateralTriangle:
+                if (_pbs.PathCurve == (byte)Extrusion.Straight)
+                    {
+                    volume *= 0.32475953f;
+                    if (hollowAmount > 0.0)
+                        {
+                        // calculate the hollow volume by it's shape compared to the prim shape
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Same:
+                            case HollowShape.Triangle:
+                                hollowVolume *= .25f;
+                                break;
+                            case HollowShape.Square:
+                                hollowVolume *= 0.499849f * 3.07920140172638f;
+                                break;
+                            case HollowShape.Circle:
+                                // Hollow shape is a perfect cyllinder in respect to the cube's scale
+                                // Cyllinder hollow volume calculation
+                                hollowVolume *= 0.1963495f * 3.07920140172638f;
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                else if (_pbs.PathCurve == (byte)Extrusion.Curve1)
+                    {
+                    volume *= 0.32475953f;
+                    volume *= 0.01f * (float)(200 - _pbs.PathScaleX);
+                    tmp = 1.0f - .02f * (float)(200 - _pbs.PathScaleY);
+                    volume *= (1.0f - tmp * tmp);
+                    if (hollowAmount > 0.0)
+                        {
+                        hollowVolume *= hollowAmount;
+                        switch (_pbs.HollowShape)
+                            {
+                            case HollowShape.Same:
+                            case HollowShape.Triangle:
+                                hollowVolume *= .25f;
+                                break;
+                            case HollowShape.Square:
+                                hollowVolume *= 0.499849f * 3.07920140172638f;
+                                break;
+                            case HollowShape.Circle:
+                                hollowVolume *= 0.1963495f * 3.07920140172638f;
+                                break;
+                            default:
+                                hollowVolume = 0;
+                                break;
+                            }
+                        volume *= (1.0f - hollowVolume);
+                        }
+                    }
+                    break;
+            default:
+                break;
+            }
+        float taperX1;
+        float taperY1;
+        float taperX;
+        float taperY;
+        float pathBegin;
+        float pathEnd;
+        float profileBegin;
+        float profileEnd;
+        if (_pbs.PathCurve == (byte)Extrusion.Straight || _pbs.PathCurve == (byte)Extrusion.Flexible)
+            {
+            taperX1 = _pbs.PathScaleX * 0.01f;
+            if (taperX1 > 1.0f)
+                taperX1 = 2.0f - taperX1;
+            taperX = 1.0f - taperX1;
+            taperY1 = _pbs.PathScaleY * 0.01f;
+            if (taperY1 > 1.0f)
+                taperY1 = 2.0f - taperY1;
+            taperY = 1.0f - taperY1;
+            }
+        else
+            {
+            taperX = _pbs.PathTaperX * 0.01f;
+            if (taperX < 0.0f)
+                taperX = -taperX;
+            taperX1 = 1.0f - taperX;
+            taperY = _pbs.PathTaperY * 0.01f;
+            if (taperY < 0.0f)
+                taperY = -taperY;
+            taperY1 = 1.0f - taperY;
+            }
+        volume *= (taperX1 * taperY1 + 0.5f * (taperX1 * taperY + taperX * taperY1) + 0.3333333333f * taperX * taperY);
+        pathBegin = (float)_pbs.PathBegin * 2.0e-5f;
+        pathEnd = 1.0f - (float)_pbs.PathEnd * 2.0e-5f;
+        volume *= (pathEnd - pathBegin);
+        // this is crude aproximation
+        profileBegin = (float)_pbs.ProfileBegin * 2.0e-5f;
+        profileEnd = 1.0f - (float)_pbs.ProfileEnd * 2.0e-5f;
+        volume *= (profileEnd - profileBegin);
+        returnMass = _density * volume;
+        if (IsRootOfLinkset)
+        {
+            foreach (BSPrim prim in _childrenPrims)
+            {
+                returnMass += prim.CalculateMass();
+            }
+        }
+        if (returnMass <= 0)
+            returnMass = 0.0001f;
+        if (returnMass > _scene.MaximumObjectMass)
+            returnMass = _scene.MaximumObjectMass;
+        return returnMass;
+    }// end CalculateMass
+    #endregion Mass Calculation
+    // Create the geometry information in Bullet for later use
+    // No locking here because this is done when we know physics is not simulating
+    private void CreateGeom()
+    {
+        // 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);
+            BulletSimAPI.DestroyHull(_scene.WorldID, _hullKey);
+            _hullKey = 0;
+            _hulls.Clear();
+        }
+        if (_mesh == null)
+        {
+            // the mesher thought this was too simple to mesh. Use a native Bullet collision shape.
+            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: mesh null. Defaulting to sphere of size {1}", LogHeader, _size);
+                    _shapeType = ShapeData.PhysicsShapeType.SHAPE_SPHERE;
+                    // Bullet native objects are scaled by the Bullet engine so pass the size in
+                    _scale = _size;
+                }
+            }
+            else
+            {
+                // m_log.DebugFormat("{0}: CreateGeom: mesh null. Defaulting to box. lid={1}, size={2}", LogHeader, LocalID,  _size);
+                _shapeType = ShapeData.PhysicsShapeType.SHAPE_BOX;
+                _scale = _size;
+            }
+        }
+        else
+        {
+            int[] indices = _mesh.getIndexListAsInt();
+            List<OMV.Vector3> vertices = _mesh.getVertexList();
+            //format conversion from IMesh format to DecompDesc format
+            List<int> convIndices = new List<int>();
+            List<float3> convVertices = new List<float3>();
+            for (int ii = 0; ii < indices.GetLength(0); ii++)
+            {
+                convIndices.Add(indices[ii]);
+            }
+            foreach (OMV.Vector3 vv in vertices)
+            {
+                convVertices.Add(new float3(vv.X, vv.Y, vv.Z));
+            }
+            // setup and do convex hull conversion
+            _hulls = new List<ConvexResult>();
+            DecompDesc dcomp = new DecompDesc();
+            dcomp.mIndices = convIndices;
+            dcomp.mVertices = convVertices;
+            ConvexBuilder convexBuilder = new ConvexBuilder(HullReturn);
+            // create the hull into the _hulls variable
+            convexBuilder.process(dcomp);
+            // Convert the vertices and indices for passing to unmanaged
+            // The hull information is passed as a large floating point array. 
+            // The format is:
+            //  convHulls[0] = number of hulls
+            //  convHulls[1] = number of vertices in first hull
+            //  convHulls[2] = hull centroid X coordinate
+            //  convHulls[3] = hull centroid Y coordinate
+            //  convHulls[4] = hull centroid Z coordinate
+            //  convHulls[5] = first hull vertex X
+            //  convHulls[6] = first hull vertex Y
+            //  convHulls[7] = first hull vertex Z
+            //  convHulls[8] = second hull vertex X
+            //  ...
+            //  convHulls[n] = number of vertices in second hull
+            //  convHulls[n+1] = second hull centroid X coordinate
+            //  ...
+            //
+            // TODO: is is very inefficient. Someday change the convex hull generator to return
+            //   data structures that do not need to be converted in order to pass to Bullet.
+            //   And maybe put the values directly into pinned memory rather than marshaling.
+            int hullCount = _hulls.Count;
+            int totalVertices = 1;          // include one for the count of the hulls
+            foreach (ConvexResult cr in _hulls)
+            {
+                totalVertices += 4;                         // add four for the vertex count and centroid
+                totalVertices += cr.HullIndices.Count * 3;  // we pass just triangles
+            }
+            float[] convHulls = new float[totalVertices];
+            convHulls[0] = (float)hullCount;
+            int jj = 1;
+            foreach (ConvexResult cr in _hulls)
+            {
+                // copy vertices for index access
+                float3[] verts = new float3[cr.HullVertices.Count];
+                int kk = 0;
+                foreach (float3 ff in cr.HullVertices)
+                {
+                    verts[kk++] = ff;
+                }
+                // add to the array one hull's worth of data
+                convHulls[jj++] = cr.HullIndices.Count;
+                convHulls[jj++] = 0f;   // centroid x,y,z
+                convHulls[jj++] = 0f;
+                convHulls[jj++] = 0f;
+                foreach (int ind in cr.HullIndices)
+                {
+                    convHulls[jj++] = verts[ind].x;
+                    convHulls[jj++] = verts[ind].y;
+                    convHulls[jj++] = verts[ind].z;
+                }
+            }
+            // create the hull definition in Bullet
+            _hullKey = (ulong)_pbs.GetHashCode();
+            // m_log.DebugFormat("{0}: CreateGeom: calling CreateHull. lid={1}, key={2}, hulls={3}", LogHeader, _localID, _hullKey, hullCount);
+            BulletSimAPI.CreateHull(_scene.WorldID, _hullKey, hullCount, convHulls);
+            _shapeType = ShapeData.PhysicsShapeType.SHAPE_HULL;
+            // meshes are already scaled by the meshmerizer
+            _scale = new OMV.Vector3(1f, 1f, 1f);
+        }
+        return;
+    }
+    // Callback from convex hull creater with a newly created hull.
+    // Just add it to the collection of hulls for this shape.
+    private void HullReturn(ConvexResult result)
+    {
+        _hulls.Add(result);
+        return;
+    }
+    // Create an object in Bullet
+    // No locking here because this is done when the physics engine is not simulating
+    private void CreateObject()
+    {
+        if (IsRootOfLinkset)
+        {
+            // Create a linkset around this object
+            // CreateLinksetWithCompoundHull();
+            CreateLinksetWithConstraints();
+        }
+        else
+        {
+            // simple object
+            ShapeData shape;
+            FillShapeInfo(out shape);
+            BulletSimAPI.CreateObject(_scene.WorldID, shape);
+        }
+    }
+    // Create a linkset by creating a compound hull at the root prim that consists of all
+    // the children.
+    // NOTE: This does not allow proper collisions with the children prims so it is not a workable solution
+    void CreateLinksetWithCompoundHull()
+    {
+        // If I am the root prim of a linkset, replace my physical shape with all the
+        // pieces of the children.
+        // All of the children should have called CreateGeom so they have a hull
+        // in the physics engine already. Here we pull together all of those hulls
+        // into one shape.
+        int totalPrimsInLinkset = _childrenPrims.Count + 1;
+        // m_log.DebugFormat("{0}: CreateLinkset. Root prim={1}, prims={2}", LogHeader, LocalID, totalPrimsInLinkset);
+        ShapeData[] shapes = new ShapeData[totalPrimsInLinkset];
+        FillShapeInfo(out shapes[0]);
+        int ii = 1;
+        foreach (BSPrim prim in _childrenPrims)
+        {
+            // m_log.DebugFormat("{0}: CreateLinkset: adding prim {1}", LogHeader, prim.LocalID);
+            prim.FillShapeInfo(out shapes[ii]);
+            ii++;
+        }
+        BulletSimAPI.CreateLinkset(_scene.WorldID, totalPrimsInLinkset, shapes);
+    }
+    // Copy prim's info into the BulletSim shape description structure
+    public void FillShapeInfo(out ShapeData shape)
+    {
+        shape.ID = _localID;
+        shape.Type = _shapeType;
+        shape.Position = _position;
+        shape.Rotation = _orientation;
+        shape.Velocity = _velocity;
+        shape.Scale = _scale;
+        shape.Mass = _isPhysical ? _mass : 0f;
+        shape.Buoyancy = _buoyancy;
+        shape.MeshKey = _hullKey;
+        shape.Friction = _friction;
+        shape.Restitution = _restitution;
+        shape.Collidable = (!IsPhantom) ? ShapeData.numericTrue : ShapeData.numericFalse;
+        shape.Static = _isPhysical ? ShapeData.numericFalse : ShapeData.numericTrue;
+    }
+    // Create the linkset by putting constraints between the objects of the set so they cannot move
+    // relative to each other.
+    // TODO: make this more effeicient: a large linkset gets rebuilt over and over and prims are added
+    void CreateLinksetWithConstraints()
+    {
+        // m_log.DebugFormat("{0}: CreateLinkset. Root prim={1}, prims={2}", LogHeader, LocalID, _childrenPrims.Count+1);
+        // remove any constraints that might be in place
+        foreach (BSPrim prim in _childrenPrims)
+        {
+            // m_log.DebugFormat("{0}: CreateObject: RemoveConstraint between root prim {1} and child prim {2}", LogHeader, LocalID, prim.LocalID);
+            BulletSimAPI.RemoveConstraint(_scene.WorldID, LocalID, prim.LocalID);
+        }
+        // create constraints between the root prim and each of the children
+        foreach (BSPrim prim in _childrenPrims)
+        {
+            // m_log.DebugFormat("{0}: CreateObject: AddConstraint between root prim {1} and child prim {2}", LogHeader, LocalID, prim.LocalID);
+            // Zero motion for children so they don't interpolate
+            prim.ZeroMotion();
+            // relative position normalized to the root prim
+            OMV.Vector3 childRelativePosition = (prim._position - this._position) * OMV.Quaternion.Inverse(this._orientation);
+            // relative rotation of the child to the parent
+            OMV.Quaternion relativeRotation = OMV.Quaternion.Inverse(prim._orientation) * this._orientation;
+            // this is a constraint that allows no freedom of movement between the two objects
+            // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
+            BulletSimAPI.AddConstraint(_scene.WorldID, LocalID, prim.LocalID, 
+                childRelativePosition,
+                relativeRotation,
+                OMV.Vector3.Zero,
+                OMV.Quaternion.Identity,
+                OMV.Vector3.Zero, OMV.Vector3.Zero,
+                OMV.Vector3.Zero, OMV.Vector3.Zero);
+        }
+    }
+    // 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()
+    {
+        // If this object is complex or we are the root of a linkset, build a mesh.
+        // The root of a linkset must be a mesh so we can create the linked compound object.
+        // if (_scene.NeedsMeshing(_pbs) || IsRootOfLinkset )
+        if (_scene.NeedsMeshing(_pbs))  // linksets with constraints don't need a root mesh
+        {
+            // m_log.DebugFormat("{0}: RecreateGeomAndObject: creating mesh", LogHeader);
+            _mesh = _scene.mesher.CreateMesh(_avName, _pbs, _size, _scene.MeshLOD, _isPhysical);
+        }
+        else
+        {
+            // implement the shape with a Bullet native shape.
+            _mesh = null;
+        }
+        CreateGeom();
+        CreateObject();
+        return;
+    }
+    // The physics engine says that properties have updated. Update same and inform
+    // the world that things have changed.
+    // TODO: do we really need to check for changed? Maybe just copy values and call RequestPhysicsterseUpdate()
+    enum UpdatedProperties {
+        Position      = 1 << 0,
+        Rotation      = 1 << 1,
+        Velocity      = 1 << 2,
+        Acceleration  = 1 << 3,
+        RotationalVel = 1 << 4
+    }
+    const float ROTATION_TOLERANCE = 0.01f;
+    const float VELOCITY_TOLERANCE = 0.001f;
+    const float POSITION_TOLERANCE = 0.05f;
+    const float ACCELERATION_TOLERANCE = 0.01f;
+    const float ROTATIONAL_VELOCITY_TOLERANCE = 0.01f;
+    const bool SHOULD_DAMP_UPDATES = false;
+    public void UpdateProperties(EntityProperties entprop)
+    {
+        UpdatedProperties changed = 0;
+        if (SHOULD_DAMP_UPDATES)
+        {
+            // assign to the local variables so the normal set action does not happen
+            // if (_position != entprop.Position)
+            if (!_position.ApproxEquals(entprop.Position, POSITION_TOLERANCE))
+            {
+                _position = entprop.Position;
+                // m_log.DebugFormat("{0}: UpdateProperties: id={1}, pos = {2}", LogHeader, LocalID, _position);
+                changed |= UpdatedProperties.Position;
+            }
+            // if (_orientation != entprop.Rotation)
+            if (!_orientation.ApproxEquals(entprop.Rotation, ROTATION_TOLERANCE))
+            {
+                _orientation = entprop.Rotation;
+                // m_log.DebugFormat("{0}: UpdateProperties: id={1}, rot = {2}", LogHeader, LocalID, _orientation);
+                changed |= UpdatedProperties.Rotation;
+            }
+            // if (_velocity != entprop.Velocity)
+            if (!_velocity.ApproxEquals(entprop.Velocity, VELOCITY_TOLERANCE))
+            {
+                _velocity = entprop.Velocity;
+                // m_log.DebugFormat("{0}: UpdateProperties: velocity = {1}", LogHeader, _velocity);
+                changed |= UpdatedProperties.Velocity;
+            }
+            // if (_acceleration != entprop.Acceleration)
+            if (!_acceleration.ApproxEquals(entprop.Acceleration, ACCELERATION_TOLERANCE))
+            {
+                _acceleration = entprop.Acceleration;
+                // m_log.DebugFormat("{0}: UpdateProperties: acceleration = {1}", LogHeader, _acceleration);
+                changed |= UpdatedProperties.Acceleration;
+            }
+            // if (_rotationalVelocity != entprop.RotationalVelocity)
+            if (!_rotationalVelocity.ApproxEquals(entprop.RotationalVelocity, ROTATIONAL_VELOCITY_TOLERANCE))
+            {
+                _rotationalVelocity = entprop.RotationalVelocity;
+                // m_log.DebugFormat("{0}: UpdateProperties: rotationalVelocity = {1}", LogHeader, _rotationalVelocity);
+                changed |= UpdatedProperties.RotationalVel;
+            }
+            if (changed != 0)
+            {
+                // m_log.DebugFormat("{0}: UpdateProperties: id={1}, c={2}, pos={3}, rot={4}", LogHeader, LocalID, changed, _position, _orientation);
+                // Only update the position of single objects and linkset roots
+                if (this._parentPrim == null)
+                {
+                    // m_log.DebugFormat("{0}: RequestTerseUpdate. id={1}, ch={2}, pos={3}, rot={4}", LogHeader, LocalID, changed, _position, _orientation);
+                    base.RequestPhysicsterseUpdate();
+                }
+            }
+        }
+        else
+        {
+            // Don't check for damping here -- it's done in BulletSim and SceneObjectPart.
+            // Only updates only for individual prims and for the root object of a linkset.
+            if (this._parentPrim == null)
+            {
+                // Assign to the local variables so the normal set action does not happen
+                _position = entprop.Position;
+                _orientation = entprop.Rotation;
+                _velocity = entprop.Velocity;
+                _acceleration = entprop.Acceleration;
+                _rotationalVelocity = entprop.RotationalVelocity;
+                // m_log.DebugFormat("{0}: RequestTerseUpdate. id={1}, ch={2}, pos={3}, rot={4}", LogHeader, LocalID, changed, _position, _orientation);
+                base.RequestPhysicsterseUpdate();
+            }
+        }
+    }
+    // I've collided with something
+    public void Collide(uint collidingWith, ActorTypes type, OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth)
+    {
+        // m_log.DebugFormat("{0}: Collide: ms={1}, id={2}, with={3}", LogHeader, _subscribedEventsMs, LocalID, collidingWith);
+        // The following lines make IsColliding() and IsCollidingGround() work
+        _collidingStep = _scene.SimulationStep;
+        if (collidingWith == BSScene.TERRAIN_ID || collidingWith == BSScene.GROUNDPLANE_ID)
+        {
+            _collidingGroundStep = _scene.SimulationStep;
+        }
+        if (_subscribedEventsMs == 0) return;   // nothing in the object is waiting for collision events
+        // throttle the collisions to the number of milliseconds specified in the subscription
+        int nowTime = _scene.SimulationNowTime;
+        if (nowTime < (_lastCollisionTime + _subscribedEventsMs)) return;
+        _lastCollisionTime = nowTime;
+        // create the event for the collision
+        Dictionary<uint, ContactPoint> contactPoints = new Dictionary<uint, ContactPoint>();
+        contactPoints.Add(collidingWith, new ContactPoint(contactPoint, contactNormal, pentrationDepth));
+        CollisionEventUpdate args = new CollisionEventUpdate(LocalID, (int)type, 1, contactPoints);
+        base.SendCollisionUpdate(args);
+    }
+}
+}