vh: update BulletSim (OpenSim/Region/Physics/BulletSPlugin

and DLL/SO) to ac6dcd35fb77f118fc6c3d72cb029591306c7e99
(Mon May 6 21:10:02 2013 -0400) on top of 0.7.5-postfixes.

1 files changed, 555 insertions, 271 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
index 13c2539..c16b7d3 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSDynamics.cs
@@ -35,17 +35,19 @@ using System.Collections.Generic;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using OpenMetaverse;
+using OpenSim.Framework;
 using OpenSim.Region.Physics.Manager;
 
 namespace OpenSim.Region.Physics.BulletSPlugin
 {
-    public sealed class BSDynamics
+    public sealed class BSDynamics : BSActor
     {
         private static string LogHeader = "[BULLETSIM VEHICLE]";
 
-        private BSScene PhysicsScene { get; set; }
         // the prim this dynamic controller belongs to
-        private BSPrim Prim { get; set; }
+        private BSPrim ControllingPrim { get; set; }
+
+        private bool m_haveRegisteredForSceneEvents;
 
         // mass of the vehicle fetched each time we're calles
         private float m_vehicleMass;
@@ -108,10 +110,9 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         private float m_VhoverEfficiency = 0f;
         private float m_VhoverTimescale = 0f;
         private float m_VhoverTargetHeight = -1.0f;     // if <0 then no hover, else its the current target height
-        private float m_VehicleBuoyancy = 0f;           //KF: m_VehicleBuoyancy is set by VEHICLE_BUOYANCY for a vehicle.
-                    // Modifies gravity. Slider between -1 (double-gravity) and 1 (full anti-gravity)
-                    // KF: So far I have found no good method to combine a script-requested .Z velocity and gravity.
-                    // Therefore only m_VehicleBuoyancy=1 (0g) will use the script-requested .Z velocity.
+        // Modifies gravity. Slider between -1 (double-gravity) and 1 (full anti-gravity)
+        private float m_VehicleBuoyancy = 0f;
+        private Vector3 m_VehicleGravity = Vector3.Zero;    // Gravity computed when buoyancy set
 
         //Attractor properties
         private BSVMotor m_verticalAttractionMotor = new BSVMotor("VerticalAttraction");
@@ -124,22 +125,51 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         static readonly float PIOverFour = ((float)Math.PI) / 4f;
         static readonly float PIOverTwo = ((float)Math.PI) / 2f;
 
-        public BSDynamics(BSScene myScene, BSPrim myPrim)
+        // For debugging, flags to turn on and off individual corrections.
+        public bool enableAngularVerticalAttraction;
+        public bool enableAngularDeflection;
+        public bool enableAngularBanking;
+
+        public BSDynamics(BSScene myScene, BSPrim myPrim, string actorName)
+            : base(myScene, myPrim, actorName)
         {
-            PhysicsScene = myScene;
-            Prim = myPrim;
+            ControllingPrim = myPrim;
             Type = Vehicle.TYPE_NONE;
+            m_haveRegisteredForSceneEvents = false;
+            SetupVehicleDebugging();
+        }
+
+        // Stopgap debugging enablement. Allows source level debugging but still checking
+        //    in changes by making enablement of debugging flags from INI file.
+        public void SetupVehicleDebugging()
+        {
+            enableAngularVerticalAttraction = true;
+            enableAngularDeflection = false;
+            enableAngularBanking = true;
+            if (BSParam.VehicleDebuggingEnable)
+            {
+                enableAngularVerticalAttraction = true;
+                enableAngularDeflection = false;
+                enableAngularBanking = false;
+            }
         }
 
         // Return 'true' if this vehicle is doing vehicle things
         public bool IsActive
         {
-            get { return Type != Vehicle.TYPE_NONE && Prim.IsPhysical; }
+            get { return (Type != Vehicle.TYPE_NONE && ControllingPrim.IsPhysicallyActive); }
+        }
+
+        // Return 'true' if this a vehicle that should be sitting on the ground
+        public bool IsGroundVehicle
+        {
+            get { return (Type == Vehicle.TYPE_CAR || Type == Vehicle.TYPE_SLED); }
         }
 
-        internal void ProcessFloatVehicleParam(Vehicle pParam, float pValue)
+        #region Vehicle parameter setting
+        public void ProcessFloatVehicleParam(Vehicle pParam, float pValue)
         {
-            VDetailLog("{0},ProcessFloatVehicleParam,param={1},val={2}", Prim.LocalID, pParam, pValue);
+            VDetailLog("{0},ProcessFloatVehicleParam,param={1},val={2}", ControllingPrim.LocalID, pParam, pValue);
             switch (pParam)
             {
                 case Vehicle.ANGULAR_DEFLECTION_EFFICIENCY:
@@ -167,6 +197,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     break;
                 case Vehicle.BUOYANCY:
                     m_VehicleBuoyancy = ClampInRange(-1f, pValue, 1f);
+                    m_VehicleGravity = ControllingPrim.ComputeGravity(m_VehicleBuoyancy);
                     break;
                 case Vehicle.HOVER_EFFICIENCY:
                     m_VhoverEfficiency = ClampInRange(0f, pValue, 1f);
@@ -204,15 +235,14 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 // set all of the components to the same value
                 case Vehicle.ANGULAR_FRICTION_TIMESCALE:
                     m_angularFrictionTimescale = new Vector3(pValue, pValue, pValue);
-                    m_angularMotor.FrictionTimescale = m_angularFrictionTimescale;
                     break;
                 case Vehicle.ANGULAR_MOTOR_DIRECTION:
                     m_angularMotorDirection = new Vector3(pValue, pValue, pValue);
+                    m_angularMotor.Zero();
                     m_angularMotor.SetTarget(m_angularMotorDirection);
                     break;
                 case Vehicle.LINEAR_FRICTION_TIMESCALE:
                     m_linearFrictionTimescale = new Vector3(pValue, pValue, pValue);
-                    m_linearMotor.FrictionTimescale = m_linearFrictionTimescale;
                     break;
                 case Vehicle.LINEAR_MOTOR_DIRECTION:
                     m_linearMotorDirection = new Vector3(pValue, pValue, pValue);
@@ -228,12 +258,11 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
         internal void ProcessVectorVehicleParam(Vehicle pParam, Vector3 pValue)
         {
-            VDetailLog("{0},ProcessVectorVehicleParam,param={1},val={2}", Prim.LocalID, pParam, pValue);
+            VDetailLog("{0},ProcessVectorVehicleParam,param={1},val={2}", ControllingPrim.LocalID, pParam, pValue);
             switch (pParam)
             {
                 case Vehicle.ANGULAR_FRICTION_TIMESCALE:
                     m_angularFrictionTimescale = new Vector3(pValue.X, pValue.Y, pValue.Z);
-                    m_angularMotor.FrictionTimescale = m_angularFrictionTimescale;
                     break;
                 case Vehicle.ANGULAR_MOTOR_DIRECTION:
                     // Limit requested angular speed to 2 rps= 4 pi rads/sec
@@ -241,11 +270,11 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     pValue.Y = ClampInRange(-12.56f, pValue.Y, 12.56f);
                     pValue.Z = ClampInRange(-12.56f, pValue.Z, 12.56f);
                     m_angularMotorDirection = new Vector3(pValue.X, pValue.Y, pValue.Z);
+                    m_angularMotor.Zero();
                     m_angularMotor.SetTarget(m_angularMotorDirection);
                     break;
                 case Vehicle.LINEAR_FRICTION_TIMESCALE:
                     m_linearFrictionTimescale = new Vector3(pValue.X, pValue.Y, pValue.Z);
-                    m_linearMotor.FrictionTimescale = m_linearFrictionTimescale;
                     break;
                 case Vehicle.LINEAR_MOTOR_DIRECTION:
                     m_linearMotorDirection = new Vector3(pValue.X, pValue.Y, pValue.Z);
@@ -263,7 +292,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
         internal void ProcessRotationVehicleParam(Vehicle pParam, Quaternion pValue)
         {
-            VDetailLog("{0},ProcessRotationalVehicleParam,param={1},val={2}", Prim.LocalID, pParam, pValue);
+            VDetailLog("{0},ProcessRotationalVehicleParam,param={1},val={2}", ControllingPrim.LocalID, pParam, pValue);
             switch (pParam)
             {
                 case Vehicle.REFERENCE_FRAME:
@@ -277,7 +306,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
         internal void ProcessVehicleFlags(int pParam, bool remove)
         {
-            VDetailLog("{0},ProcessVehicleFlags,param={1},remove={2}", Prim.LocalID, pParam, remove);
+            VDetailLog("{0},ProcessVehicleFlags,param={1},remove={2}", ControllingPrim.LocalID, pParam, remove);
             VehicleFlag parm = (VehicleFlag)pParam;
             if (pParam == -1)
                 m_flags = (VehicleFlag)0;
@@ -290,9 +319,9 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             }
         }
 
-        internal void ProcessTypeChange(Vehicle pType)
+        public void ProcessTypeChange(Vehicle pType)
         {
-            VDetailLog("{0},ProcessTypeChange,type={1}", Prim.LocalID, pType);
+            VDetailLog("{0},ProcessTypeChange,type={1}", ControllingPrim.LocalID, pType);
             // Set Defaults For Type
             Type = pType;
             switch (pType)
@@ -526,81 +555,136 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     break;
             }
 
-            // Update any physical parameters based on this type.
-            Refresh();
-
-            m_linearMotor = new BSVMotor("LinearMotor", m_linearMotorTimescale,
-                                m_linearMotorDecayTimescale, m_linearFrictionTimescale,
-                                1f);
-            m_linearMotor.PhysicsScene = PhysicsScene;  // DEBUG DEBUG DEBUG (enables detail logging)
+            m_linearMotor = new BSVMotor("LinearMotor", m_linearMotorTimescale, m_linearMotorDecayTimescale, 1f);
+            m_linearMotor.PhysicsScene = m_physicsScene;  // DEBUG DEBUG DEBUG (enables detail logging)
 
-            m_angularMotor = new BSVMotor("AngularMotor", m_angularMotorTimescale,
-                                m_angularMotorDecayTimescale, m_angularFrictionTimescale,
-                                1f);
-            m_angularMotor.PhysicsScene = PhysicsScene;  // DEBUG DEBUG DEBUG (enables detail logging)
+            m_angularMotor = new BSVMotor("AngularMotor", m_angularMotorTimescale, m_angularMotorDecayTimescale, 1f);
+            m_angularMotor.PhysicsScene = m_physicsScene;  // DEBUG DEBUG DEBUG (enables detail logging)
 
+            /*  Not implemented
             m_verticalAttractionMotor = new BSVMotor("VerticalAttraction", m_verticalAttractionTimescale,
                                 BSMotor.Infinite, BSMotor.InfiniteVector,
                                 m_verticalAttractionEfficiency);
             // Z goes away and we keep X and Y
-            m_verticalAttractionMotor.FrictionTimescale = new Vector3(BSMotor.Infinite, BSMotor.Infinite, 0.1f);
             m_verticalAttractionMotor.PhysicsScene = PhysicsScene;  // DEBUG DEBUG DEBUG (enables detail logging)
+             */
+
+            if (this.Type == Vehicle.TYPE_NONE)
+            {
+                UnregisterForSceneEvents();
+            }
+            else
+            {
+                RegisterForSceneEvents();
+            }
+
+            // Update any physical parameters based on this type.
+            Refresh();
+        }
+        #endregion // Vehicle parameter setting
+
+        // BSActor.Refresh()
+        public override void Refresh()
+        {
+            // If asking for a refresh, reset the physical parameters before the next simulation step.
+            // Called whether active or not since the active state may be updated before the next step.
+            m_physicsScene.PostTaintObject("BSDynamics.Refresh", ControllingPrim.LocalID, delegate()
+            {
+                SetPhysicalParameters();
+            });
         }
 
         // Some of the properties of this prim may have changed.
         // Do any updating needed for a vehicle
-        public void Refresh()
+        private void SetPhysicalParameters()
         {
             if (IsActive)
             {
                 // Remember the mass so we don't have to fetch it every step
-                m_vehicleMass = Prim.Linkset.LinksetMass;
+                m_vehicleMass = ControllingPrim.TotalMass;
 
                 // Friction affects are handled by this vehicle code
-                float friction = 0f;
-                PhysicsScene.PE.SetFriction(Prim.PhysBody, friction);
+                m_physicsScene.PE.SetFriction(ControllingPrim.PhysBody, BSParam.VehicleFriction);
+                m_physicsScene.PE.SetRestitution(ControllingPrim.PhysBody, BSParam.VehicleRestitution);
 
                 // Moderate angular movement introduced by Bullet.
                 // TODO: possibly set AngularFactor and LinearFactor for the type of vehicle.
                 //     Maybe compute linear and angular factor and damping from params.
-                float angularDamping = BSParam.VehicleAngularDamping;
-                PhysicsScene.PE.SetAngularDamping(Prim.PhysBody, angularDamping);
+                m_physicsScene.PE.SetAngularDamping(ControllingPrim.PhysBody, BSParam.VehicleAngularDamping);
+                m_physicsScene.PE.SetLinearFactor(ControllingPrim.PhysBody, BSParam.VehicleLinearFactor);
+                m_physicsScene.PE.SetAngularFactorV(ControllingPrim.PhysBody, BSParam.VehicleAngularFactor);
 
                 // Vehicles report collision events so we know when it's on the ground
-                PhysicsScene.PE.AddToCollisionFlags(Prim.PhysBody, CollisionFlags.BS_VEHICLE_COLLISIONS);
+                m_physicsScene.PE.AddToCollisionFlags(ControllingPrim.PhysBody, CollisionFlags.BS_VEHICLE_COLLISIONS);
+
+                ControllingPrim.Inertia = m_physicsScene.PE.CalculateLocalInertia(ControllingPrim.PhysShape.physShapeInfo, m_vehicleMass);
+                m_physicsScene.PE.SetMassProps(ControllingPrim.PhysBody, m_vehicleMass, ControllingPrim.Inertia);
+                m_physicsScene.PE.UpdateInertiaTensor(ControllingPrim.PhysBody);
+
+                // Set the gravity for the vehicle depending on the buoyancy
+                // TODO: what should be done if prim and vehicle buoyancy differ?
+                m_VehicleGravity = ControllingPrim.ComputeGravity(m_VehicleBuoyancy);
+                // The actual vehicle gravity is set to zero in Bullet so we can do all the application of same.
+                m_physicsScene.PE.SetGravity(ControllingPrim.PhysBody, Vector3.Zero);
+
+                VDetailLog("{0},BSDynamics.SetPhysicalParameters,mass={1},inert={2},vehGrav={3},aDamp={4},frict={5},rest={6},lFact={7},aFact={8}",
+                        ControllingPrim.LocalID, m_vehicleMass, ControllingPrim.Inertia, m_VehicleGravity,
+                        BSParam.VehicleAngularDamping, BSParam.VehicleFriction, BSParam.VehicleRestitution,
+                        BSParam.VehicleLinearFactor, BSParam.VehicleAngularFactor
+                        );
+            }
+            else
+            {
+                if (ControllingPrim.PhysBody.HasPhysicalBody)
+                    m_physicsScene.PE.RemoveFromCollisionFlags(ControllingPrim.PhysBody, CollisionFlags.BS_VEHICLE_COLLISIONS);
+            }
+        }
 
-                Vector3 localInertia = PhysicsScene.PE.CalculateLocalInertia(Prim.PhysShape, m_vehicleMass);
-                PhysicsScene.PE.SetMassProps(Prim.PhysBody, m_vehicleMass, localInertia);
-                PhysicsScene.PE.UpdateInertiaTensor(Prim.PhysBody);
+        // BSActor.RemoveBodyDependencies
+        public override void RemoveDependencies()
+        {
+            Refresh();
+        }
 
-                Vector3 grav = PhysicsScene.DefaultGravity * (1f - Prim.Buoyancy);
-                PhysicsScene.PE.SetGravity(Prim.PhysBody, grav);
+        // BSActor.Release()
+        public override void Dispose()
+        {
+            UnregisterForSceneEvents();
+            Type = Vehicle.TYPE_NONE;
+            Enabled = false;
+            return;
+        }
 
-                VDetailLog("{0},BSDynamics.Refresh,mass={1},frict={2},inert={3},aDamp={4}",
-                                Prim.LocalID, m_vehicleMass, friction, localInertia, angularDamping);
-            }
-            else
+        private void RegisterForSceneEvents()
+        {
+            if (!m_haveRegisteredForSceneEvents)
             {
-                PhysicsScene.PE.RemoveFromCollisionFlags(Prim.PhysBody, CollisionFlags.BS_VEHICLE_COLLISIONS);
+                m_physicsScene.BeforeStep += this.Step;
+                m_physicsScene.AfterStep += this.PostStep;
+                ControllingPrim.OnPreUpdateProperty += this.PreUpdateProperty;
+                m_haveRegisteredForSceneEvents = true;
             }
         }
 
-        public bool RemoveBodyDependencies(BSPhysObject prim)
+        private void UnregisterForSceneEvents()
         {
-            // If active, we need to add our properties back when the body is rebuilt.
-            return IsActive;
+            if (m_haveRegisteredForSceneEvents)
+            {
+                m_physicsScene.BeforeStep -= this.Step;
+                m_physicsScene.AfterStep -= this.PostStep;
+                ControllingPrim.OnPreUpdateProperty -= this.PreUpdateProperty;
+                m_haveRegisteredForSceneEvents = false;
+            }
         }
 
-        public void RestoreBodyDependencies(BSPhysObject prim)
+        private void PreUpdateProperty(ref EntityProperties entprop)
         {
-            if (Prim.LocalID != prim.LocalID)
+            // A temporary kludge to suppress the rotational effects introduced on vehicles by Bullet
+            // TODO: handle physics introduced by Bullet with computed vehicle physics.
+            if (IsActive)
             {
-                // The call should be on us by our prim. Error if not.
-                PhysicsScene.Logger.ErrorFormat("{0} RestoreBodyDependencies: called by not my prim. passedLocalID={1}, vehiclePrimLocalID={2}",
-                                LogHeader, prim.LocalID, Prim.LocalID);
-                return;
+                entprop.RotationalVelocity = Vector3.Zero;
             }
-            Refresh();
         }
 
         #region Known vehicle value functions
@@ -617,70 +701,87 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         private Vector3 m_knownPosition;
         private Vector3 m_knownVelocity;
         private Vector3 m_knownForce;
+        private Vector3 m_knownForceImpulse;
         private Quaternion m_knownOrientation;
         private Vector3 m_knownRotationalVelocity;
         private Vector3 m_knownRotationalForce;
+        private Vector3 m_knownRotationalImpulse;
         private Vector3 m_knownForwardVelocity;    // vehicle relative forward speed
 
         private const int m_knownChangedPosition           = 1 << 0;
         private const int m_knownChangedVelocity           = 1 << 1;
         private const int m_knownChangedForce              = 1 << 2;
-        private const int m_knownChangedOrientation        = 1 << 3;
-        private const int m_knownChangedRotationalVelocity = 1 << 4;
-        private const int m_knownChangedRotationalForce    = 1 << 5;
-        private const int m_knownChangedTerrainHeight      = 1 << 6;
-        private const int m_knownChangedWaterLevel         = 1 << 7;
-        private const int m_knownChangedForwardVelocity    = 1 << 8;
-
-        private void ForgetKnownVehicleProperties()
+        private const int m_knownChangedForceImpulse       = 1 << 3;
+        private const int m_knownChangedOrientation        = 1 << 4;
+        private const int m_knownChangedRotationalVelocity = 1 << 5;
+        private const int m_knownChangedRotationalForce    = 1 << 6;
+        private const int m_knownChangedRotationalImpulse  = 1 << 7;
+        private const int m_knownChangedTerrainHeight      = 1 << 8;
+        private const int m_knownChangedWaterLevel         = 1 << 9;
+        private const int m_knownChangedForwardVelocity    = 1 <<10;
+
+        public void ForgetKnownVehicleProperties()
         {
             m_knownHas = 0;
             m_knownChanged = 0;
         }
         // Push all the changed values back into the physics engine
-        private void PushKnownChanged()
+        public void PushKnownChanged()
         {
             if (m_knownChanged != 0)
             {
                 if ((m_knownChanged & m_knownChangedPosition) != 0)
-                    Prim.ForcePosition = m_knownPosition;
+                    ControllingPrim.ForcePosition = m_knownPosition;
 
                 if ((m_knownChanged & m_knownChangedOrientation) != 0)
-                    Prim.ForceOrientation = m_knownOrientation;
+                    ControllingPrim.ForceOrientation = m_knownOrientation;
 
                 if ((m_knownChanged & m_knownChangedVelocity) != 0)
                 {
-                    Prim.ForceVelocity = m_knownVelocity;
-                    PhysicsScene.PE.SetInterpolationLinearVelocity(Prim.PhysBody, VehicleVelocity);
+                    ControllingPrim.ForceVelocity = m_knownVelocity;
+                    // Fake out Bullet by making it think the velocity is the same as last time.
+                    // Bullet does a bunch of smoothing for changing parameters.
+                    //    Since the vehicle is demanding this setting, we override Bullet's smoothing
+                    //    by telling Bullet the value was the same last time.
+                    // PhysicsScene.PE.SetInterpolationLinearVelocity(Prim.PhysBody, m_knownVelocity);
                 }
 
                 if ((m_knownChanged & m_knownChangedForce) != 0)
-                    Prim.AddForce((Vector3)m_knownForce, false, true);
+                    ControllingPrim.AddForce((Vector3)m_knownForce, false /*pushForce*/, true /*inTaintTime*/);
+
+                if ((m_knownChanged & m_knownChangedForceImpulse) != 0)
+                    ControllingPrim.AddForceImpulse((Vector3)m_knownForceImpulse, false /*pushforce*/, true /*inTaintTime*/);
 
                 if ((m_knownChanged & m_knownChangedRotationalVelocity) != 0)
                 {
-                    Prim.ForceRotationalVelocity = m_knownRotationalVelocity;
-                    // Fake out Bullet by making it think the velocity is the same as last time.
-                    PhysicsScene.PE.SetInterpolationAngularVelocity(Prim.PhysBody, m_knownRotationalVelocity);
+                    ControllingPrim.ForceRotationalVelocity = m_knownRotationalVelocity;
+                    // PhysicsScene.PE.SetInterpolationAngularVelocity(Prim.PhysBody, m_knownRotationalVelocity);
                 }
 
+                if ((m_knownChanged & m_knownChangedRotationalImpulse) != 0)
+                    ControllingPrim.ApplyTorqueImpulse((Vector3)m_knownRotationalImpulse, true /*inTaintTime*/);
+
                 if ((m_knownChanged & m_knownChangedRotationalForce) != 0)
-                    Prim.AddAngularForce((Vector3)m_knownRotationalForce, false, true);
+                {
+                    ControllingPrim.AddAngularForce((Vector3)m_knownRotationalForce, false /*pushForce*/, true /*inTaintTime*/);
+                }
 
                 // If we set one of the values (ie, the physics engine didn't do it) we must force
                 //      an UpdateProperties event to send the changes up to the simulator.
-                PhysicsScene.PE.PushUpdate(Prim.PhysBody);
+                m_physicsScene.PE.PushUpdate(ControllingPrim.PhysBody);
             }
             m_knownChanged = 0;
         }
 
         // Since the computation of terrain height can be a little involved, this routine
         //    is used to fetch the height only once for each vehicle simulation step.
+        Vector3 lastRememberedHeightPos;
         private float GetTerrainHeight(Vector3 pos)
         {
-            if ((m_knownHas & m_knownChangedTerrainHeight) == 0)
+            if ((m_knownHas & m_knownChangedTerrainHeight) == 0 || pos != lastRememberedHeightPos)
             {
-                m_knownTerrainHeight = Prim.PhysicsScene.TerrainManager.GetTerrainHeightAtXYZ(pos);
+                lastRememberedHeightPos = pos;
+                m_knownTerrainHeight = ControllingPrim.PhysScene.TerrainManager.GetTerrainHeightAtXYZ(pos);
                 m_knownHas |= m_knownChangedTerrainHeight;
             }
             return m_knownTerrainHeight;
@@ -692,7 +793,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         {
             if ((m_knownHas & m_knownChangedWaterLevel) == 0)
             {
-                m_knownWaterLevel = Prim.PhysicsScene.TerrainManager.GetWaterLevelAtXYZ(pos);
+                m_knownWaterLevel = ControllingPrim.PhysScene.TerrainManager.GetWaterLevelAtXYZ(pos);
                 m_knownHas |= m_knownChangedWaterLevel;
             }
             return (float)m_knownWaterLevel;
@@ -704,7 +805,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             {
                 if ((m_knownHas & m_knownChangedPosition) == 0)
                 {
-                    m_knownPosition = Prim.ForcePosition;
+                    m_knownPosition = ControllingPrim.ForcePosition;
                     m_knownHas |= m_knownChangedPosition;
                 }
                 return m_knownPosition;
@@ -723,7 +824,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             {
                 if ((m_knownHas & m_knownChangedOrientation) == 0)
                 {
-                    m_knownOrientation = Prim.ForceOrientation;
+                    m_knownOrientation = ControllingPrim.ForceOrientation;
                     m_knownHas |= m_knownChangedOrientation;
                 }
                 return m_knownOrientation;
@@ -742,10 +843,10 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             {
                 if ((m_knownHas & m_knownChangedVelocity) == 0)
                 {
-                    m_knownVelocity = Prim.ForceVelocity;
+                    m_knownVelocity = ControllingPrim.ForceVelocity;
                     m_knownHas |= m_knownChangedVelocity;
                 }
-                return (Vector3)m_knownVelocity;
+                return m_knownVelocity;
             }
             set
             {
@@ -755,15 +856,26 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             }
         }
 
-        private void VehicleAddForce(Vector3 aForce)
+        private void VehicleAddForce(Vector3 pForce)
         {
             if ((m_knownHas & m_knownChangedForce) == 0)
             {
                 m_knownForce = Vector3.Zero;
+                m_knownHas |= m_knownChangedForce;
             }
-            m_knownForce += aForce;
+            m_knownForce += pForce;
             m_knownChanged |= m_knownChangedForce;
-            m_knownHas |= m_knownChangedForce;
+        }
+
+        private void VehicleAddForceImpulse(Vector3 pImpulse)
+        {
+            if ((m_knownHas & m_knownChangedForceImpulse) == 0)
+            {
+                m_knownForceImpulse = Vector3.Zero;
+                m_knownHas |= m_knownChangedForceImpulse;
+            }
+            m_knownForceImpulse += pImpulse;
+            m_knownChanged |= m_knownChangedForceImpulse;
         }
 
         private Vector3 VehicleRotationalVelocity
@@ -772,7 +884,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             {
                 if ((m_knownHas & m_knownChangedRotationalVelocity) == 0)
                 {
-                    m_knownRotationalVelocity = Prim.ForceRotationalVelocity;
+                    m_knownRotationalVelocity = ControllingPrim.ForceRotationalVelocity;
                     m_knownHas |= m_knownChangedRotationalVelocity;
                 }
                 return (Vector3)m_knownRotationalVelocity;
@@ -794,6 +906,17 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             m_knownChanged |= m_knownChangedRotationalForce;
             m_knownHas |= m_knownChangedRotationalForce;
         }
+        private void VehicleAddRotationalImpulse(Vector3 pImpulse)
+        {
+            if ((m_knownHas & m_knownChangedRotationalImpulse) == 0)
+            {
+                m_knownRotationalImpulse = Vector3.Zero;
+                m_knownHas |= m_knownChangedRotationalImpulse;
+            }
+            m_knownRotationalImpulse += pImpulse;
+            m_knownChanged |= m_knownChangedRotationalImpulse;
+        }
+
         // Vehicle relative forward velocity
         private Vector3 VehicleForwardVelocity
         {
@@ -822,9 +945,6 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         {
             if (!IsActive) return;
 
-            if (PhysicsScene.VehiclePhysicalLoggingEnabled)
-                PhysicsScene.PE.DumpRigidBody(PhysicsScene.World, Prim.PhysBody);
-
             ForgetKnownVehicleProperties();
 
             MoveLinear(pTimestep);
@@ -839,106 +959,116 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             //      for the physics engine to note the changes so an UpdateProperties event will happen.
             PushKnownChanged();
 
-            if (PhysicsScene.VehiclePhysicalLoggingEnabled)
-                PhysicsScene.PE.DumpRigidBody(PhysicsScene.World, Prim.PhysBody);
+            if (m_physicsScene.VehiclePhysicalLoggingEnabled)
+                m_physicsScene.PE.DumpRigidBody(m_physicsScene.World, ControllingPrim.PhysBody);
 
-            VDetailLog("{0},BSDynamics.Step,done,pos={1},force={2},velocity={3},angvel={4}",
-                    Prim.LocalID, VehiclePosition, Prim.Force, VehicleVelocity, VehicleRotationalVelocity);
+            VDetailLog("{0},BSDynamics.Step,done,pos={1}, force={2},velocity={3},angvel={4}",
+                    ControllingPrim.LocalID, VehiclePosition, m_knownForce, VehicleVelocity, VehicleRotationalVelocity);
         }
 
-        // Apply the effect of the linear motor and other linear motions (like hover and float).
-        private void MoveLinear(float pTimestep)
+        // Called after the simulation step
+        internal void PostStep(float pTimestep)
         {
-            Vector3 linearMotorContribution = m_linearMotor.Step(pTimestep);
+            if (!IsActive) return;
 
-            // The movement computed in the linear motor is relative to the vehicle
-            //     coordinates. Rotate the movement to world coordinates.
-            linearMotorContribution *= VehicleOrientation;
+            if (m_physicsScene.VehiclePhysicalLoggingEnabled)
+                m_physicsScene.PE.DumpRigidBody(m_physicsScene.World, ControllingPrim.PhysBody);
+        }
 
-            // ==================================================================
-            // Buoyancy: force to overcome gravity.
-            // m_VehicleBuoyancy: -1=2g; 0=1g; 1=0g;
-            // So, if zero, don't change anything (let gravity happen). If one, negate the effect of gravity.
-            Vector3 buoyancyContribution =  Prim.PhysicsScene.DefaultGravity * m_VehicleBuoyancy;
+        // Apply the effect of the linear motor and other linear motions (like hover and float).
+        private void MoveLinear(float pTimestep)
+        {
+            ComputeLinearVelocity(pTimestep);
 
-            Vector3 terrainHeightContribution = ComputeLinearTerrainHeightCorrection(pTimestep);
+            ComputeLinearTerrainHeightCorrection(pTimestep);
 
-            Vector3 hoverContribution = ComputeLinearHover(pTimestep);
+            ComputeLinearHover(pTimestep);
 
             ComputeLinearBlockingEndPoint(pTimestep);
 
-            Vector3 limitMotorUpContribution = ComputeLinearMotorUp(pTimestep);
+            ComputeLinearMotorUp(pTimestep);
 
-            // ==================================================================
-            Vector3 newVelocity = linearMotorContribution
-                            + terrainHeightContribution
-                            + hoverContribution
-                            + limitMotorUpContribution;
-
-            Vector3 newForce = buoyancyContribution;
+            ApplyGravity(pTimestep);
 
             // If not changing some axis, reduce out velocity
-            if ((m_flags & (VehicleFlag.NO_X)) != 0)
-                newVelocity.X = 0;
-            if ((m_flags & (VehicleFlag.NO_Y)) != 0)
-                newVelocity.Y = 0;
-            if ((m_flags & (VehicleFlag.NO_Z)) != 0)
-                newVelocity.Z = 0;
+            if ((m_flags & (VehicleFlag.NO_X | VehicleFlag.NO_Y | VehicleFlag.NO_Z)) != 0)
+            {
+                Vector3 vel = VehicleVelocity;
+                if ((m_flags & (VehicleFlag.NO_X)) != 0)
+                    vel.X = 0;
+                if ((m_flags & (VehicleFlag.NO_Y)) != 0)
+                    vel.Y = 0;
+                if ((m_flags & (VehicleFlag.NO_Z)) != 0)
+                    vel.Z = 0;
+                VehicleVelocity = vel;
+            }
 
             // ==================================================================
             // Clamp high or low velocities
-            float newVelocityLengthSq = newVelocity.LengthSquared();
-            if (newVelocityLengthSq > 1000f)
+            float newVelocityLengthSq = VehicleVelocity.LengthSquared();
+            if (newVelocityLengthSq > BSParam.VehicleMaxLinearVelocitySquared)
             {
-                newVelocity /= newVelocity.Length();
-                newVelocity *= 1000f;
+                Vector3 origVelW = VehicleVelocity;         // DEBUG DEBUG
+                VehicleVelocity /= VehicleVelocity.Length();
+                VehicleVelocity *= BSParam.VehicleMaxLinearVelocity;
+                VDetailLog("{0},  MoveLinear,clampMax,origVelW={1},lenSq={2},maxVelSq={3},,newVelW={4}",
+                            ControllingPrim.LocalID, origVelW, newVelocityLengthSq, BSParam.VehicleMaxLinearVelocitySquared, VehicleVelocity);
             }
             else if (newVelocityLengthSq < 0.001f)
-                newVelocity = Vector3.Zero;
+                VehicleVelocity = Vector3.Zero;
 
-            // ==================================================================
-            // Stuff new linear velocity into the vehicle.
-            // Since the velocity is just being set, it is not scaled by pTimeStep. Bullet will do that for us.
-            VehicleVelocity = newVelocity;
+            VDetailLog("{0},  MoveLinear,done,isColl={1},newVel={2}", ControllingPrim.LocalID, ControllingPrim.IsColliding, VehicleVelocity );
+
+        } // end MoveLinear()
+
+        public void ComputeLinearVelocity(float pTimestep)
+        {
+            // Step the motor from the current value. Get the correction needed this step.
+            Vector3 origVelW = VehicleVelocity;             // DEBUG
+            Vector3 currentVelV = VehicleVelocity * Quaternion.Inverse(VehicleOrientation);
+            Vector3 linearMotorCorrectionV = m_linearMotor.Step(pTimestep, currentVelV);
+
+            // Friction reduces vehicle motion
+            Vector3 frictionFactorW = ComputeFrictionFactor(m_linearFrictionTimescale, pTimestep);
+            linearMotorCorrectionV -= (currentVelV * frictionFactorW);
 
-            // Other linear forces are applied as forces.
-            Vector3 totalDownForce = newForce * m_vehicleMass;
-            if (!totalDownForce.ApproxEquals(Vector3.Zero, 0.01f))
+            // Motor is vehicle coordinates. Rotate it to world coordinates
+            Vector3 linearMotorVelocityW = linearMotorCorrectionV * VehicleOrientation;
+
+            // If we're a ground vehicle, don't add any upward Z movement
+            if ((m_flags & VehicleFlag.LIMIT_MOTOR_UP) != 0)
             {
-                VehicleAddForce(totalDownForce);
+                if (linearMotorVelocityW.Z > 0f)
+                    linearMotorVelocityW.Z = 0f;
             }
 
-            VDetailLog("{0},  MoveLinear,done,newVel={1},totDown={2},IsColliding={3}",
-                                Prim.LocalID, newVelocity, totalDownForce, Prim.IsColliding);
-            VDetailLog("{0},  MoveLinear,done,linContrib={1},terrContrib={2},hoverContrib={3},limitContrib={4},buoyContrib={5}",
-                                Prim.LocalID,
-                                linearMotorContribution, terrainHeightContribution, hoverContribution, 
-                                limitMotorUpContribution, buoyancyContribution
-            );
+            // Add this correction to the velocity to make it faster/slower.
+            VehicleVelocity += linearMotorVelocityW;
 
-        } // end MoveLinear()
 
-        public Vector3 ComputeLinearTerrainHeightCorrection(float pTimestep)
+
+            VDetailLog("{0},  MoveLinear,velocity,origVelW={1},velV={2},correctV={3},correctW={4},newVelW={5},fricFact={6}",
+                        ControllingPrim.LocalID, origVelW, currentVelV, linearMotorCorrectionV,
+                        linearMotorVelocityW, VehicleVelocity, frictionFactorW);
+        }
+
+        public void ComputeLinearTerrainHeightCorrection(float pTimestep)
         {
-            Vector3 ret = Vector3.Zero;
             // If below the terrain, move us above the ground a little.
             // TODO: Consider taking the rotated size of the object or possibly casting a ray.
             if (VehiclePosition.Z < GetTerrainHeight(VehiclePosition))
             {
-                // TODO: correct position by applying force rather than forcing position.
+                // Force position because applying force won't get the vehicle through the terrain
                 Vector3 newPosition = VehiclePosition;
                 newPosition.Z = GetTerrainHeight(VehiclePosition) + 1f;
                 VehiclePosition = newPosition;
                 VDetailLog("{0},  MoveLinear,terrainHeight,terrainHeight={1},pos={2}",
-                        Prim.LocalID, GetTerrainHeight(VehiclePosition), VehiclePosition);
+                        ControllingPrim.LocalID, GetTerrainHeight(VehiclePosition), VehiclePosition);
             }
-            return ret;
         }
 
-        public Vector3 ComputeLinearHover(float pTimestep)
+        public void ComputeLinearHover(float pTimestep)
         {
-            Vector3 ret = Vector3.Zero;
-
             // m_VhoverEfficiency: 0=bouncy, 1=totally damped
             // m_VhoverTimescale: time to achieve height
             if ((m_flags & (VehicleFlag.HOVER_WATER_ONLY | VehicleFlag.HOVER_TERRAIN_ONLY | VehicleFlag.HOVER_GLOBAL_HEIGHT)) != 0)
@@ -963,7 +1093,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     if (VehiclePosition.Z > m_VhoverTargetHeight)
                         m_VhoverTargetHeight = VehiclePosition.Z;
                 }
-                
+
                 if ((m_flags & VehicleFlag.LOCK_HOVER_HEIGHT) != 0)
                 {
                     if (Math.Abs(VehiclePosition.Z - m_VhoverTargetHeight) > 0.2f)
@@ -971,26 +1101,42 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                         Vector3 pos = VehiclePosition;
                         pos.Z = m_VhoverTargetHeight;
                         VehiclePosition = pos;
+
+                        VDetailLog("{0},  MoveLinear,hover,pos={1},lockHoverHeight", ControllingPrim.LocalID, pos);
                     }
                 }
                 else
                 {
                     // Error is positive if below the target and negative if above.
-                    float verticalError = m_VhoverTargetHeight - VehiclePosition.Z;
+                    Vector3 hpos = VehiclePosition;
+                    float verticalError = m_VhoverTargetHeight - hpos.Z;
+                    float verticalCorrection = verticalError / m_VhoverTimescale;
+                    verticalCorrection *= m_VhoverEfficiency;
+
+                    hpos.Z += verticalCorrection;
+                    VehiclePosition = hpos;
+
+                    // Since we are hovering, we need to do the opposite of falling -- get rid of world Z
+                    Vector3 vel = VehicleVelocity;
+                    vel.Z = 0f;
+                    VehicleVelocity = vel;
+
+                    /*
                     float verticalCorrectionVelocity = verticalError / m_VhoverTimescale;
+                    Vector3 verticalCorrection = new Vector3(0f, 0f, verticalCorrectionVelocity);
+                    verticalCorrection *= m_vehicleMass;
 
                     // TODO: implement m_VhoverEfficiency correctly
-                    if (Math.Abs(verticalError) > m_VhoverEfficiency)
-                    {
-                        ret = new Vector3(0f, 0f, verticalCorrectionVelocity);
-                    }
+                    VehicleAddForceImpulse(verticalCorrection);
+                     */
+
+                    VDetailLog("{0},  MoveLinear,hover,pos={1},eff={2},hoverTS={3},height={4},target={5},err={6},corr={7}",
+                                    ControllingPrim.LocalID, VehiclePosition, m_VhoverEfficiency,
+                                    m_VhoverTimescale, m_VhoverHeight, m_VhoverTargetHeight,
+                                    verticalError, verticalCorrection);
                 }
 
-                VDetailLog("{0},  MoveLinear,hover,pos={1},ret={2},hoverTS={3},height={4},target={5}",
-                                Prim.LocalID, VehiclePosition, ret, m_VhoverTimescale, m_VhoverHeight, m_VhoverTargetHeight);
             }
-
-            return ret;
         }
 
         public bool ComputeLinearBlockingEndPoint(float pTimestep)
@@ -1030,7 +1176,7 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 {
                     VehiclePosition = pos;
                     VDetailLog("{0},  MoveLinear,blockingEndPoint,block={1},origPos={2},pos={3}",
-                                Prim.LocalID, m_BlockingEndPoint, posChange, pos);
+                                ControllingPrim.LocalID, m_BlockingEndPoint, posChange, pos);
                 }
             }
             return changed;
@@ -1041,34 +1187,75 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         //    used with conjunction with banking: the strength of the banking will decay when the
         //    vehicle no longer experiences collisions. The decay timescale is the same as
         //    VEHICLE_BANKING_TIMESCALE. This is to help prevent ground vehicles from steering
-        //    when they are in mid jump. 
+        //    when they are in mid jump.
         // TODO: this code is wrong. Also, what should it do for boats (height from water)?
         //    This is just using the ground and a general collision check. Should really be using
         //    a downward raycast to find what is below.
-        public Vector3 ComputeLinearMotorUp(float pTimestep)
+        public void ComputeLinearMotorUp(float pTimestep)
         {
-            Vector3 ret = Vector3.Zero;
-            float distanceAboveGround = 0f;
-
             if ((m_flags & (VehicleFlag.LIMIT_MOTOR_UP)) != 0)
             {
+                // This code tries to decide if the object is not on the ground and then pushing down
+                /*
                 float targetHeight = Type == Vehicle.TYPE_BOAT ? GetWaterLevel(VehiclePosition) : GetTerrainHeight(VehiclePosition);
                 distanceAboveGround = VehiclePosition.Z - targetHeight;
                 // Not colliding if the vehicle is off the ground
                 if (!Prim.IsColliding)
                 {
                     // downForce = new Vector3(0, 0, -distanceAboveGround / m_bankingTimescale);
-                    ret = new Vector3(0, 0, -distanceAboveGround);
+                    VehicleVelocity += new Vector3(0, 0, -distanceAboveGround);
                 }
                 // TODO: this calculation is wrong. From the description at
                 //     (http://wiki.secondlife.com/wiki/Category:LSL_Vehicle), the downForce
                 //     has a decay factor. This says this force should
                 //     be computed with a motor.
                 // TODO: add interaction with banking.
-            }
-            VDetailLog("{0},  MoveLinear,limitMotorUp,distAbove={1},colliding={2},ret={3}",
+                VDetailLog("{0},  MoveLinear,limitMotorUp,distAbove={1},colliding={2},ret={3}",
                                 Prim.LocalID, distanceAboveGround, Prim.IsColliding, ret);
-            return ret;
+                 */
+
+                // Another approach is to measure if we're going up. If going up and not colliding,
+                //     the vehicle is in the air.  Fix that by pushing down.
+                if (!ControllingPrim.IsColliding && VehicleVelocity.Z > 0.1)
+                {
+                    // Get rid of any of the velocity vector that is pushing us up.
+                    float upVelocity = VehicleVelocity.Z;
+                    VehicleVelocity += new Vector3(0, 0, -upVelocity);
+
+                    /*
+                    // If we're pointed up into the air, we should nose down
+                    Vector3 pointingDirection = Vector3.UnitX * VehicleOrientation;
+                    // The rotation around the Y axis is pitch up or down
+                    if (pointingDirection.Y > 0.01f)
+                    {
+                        float angularCorrectionForce = -(float)Math.Asin(pointingDirection.Y);
+                        Vector3 angularCorrectionVector = new Vector3(0f, angularCorrectionForce, 0f);
+                        // Rotate into world coordinates and apply to vehicle
+                        angularCorrectionVector *= VehicleOrientation;
+                        VehicleAddAngularForce(angularCorrectionVector);
+                        VDetailLog("{0},  MoveLinear,limitMotorUp,newVel={1},pntDir={2},corrFrc={3},aCorr={4}",
+                                    Prim.LocalID, VehicleVelocity, pointingDirection, angularCorrectionForce, angularCorrectionVector);
+                    }
+                        */
+                    VDetailLog("{0},  MoveLinear,limitMotorUp,collide={1},upVel={2},newVel={3}",
+                                    ControllingPrim.LocalID, ControllingPrim.IsColliding, upVelocity, VehicleVelocity);
+                }
+            }
+        }
+
+        private void ApplyGravity(float pTimeStep)
+        {
+            Vector3 appliedGravity = m_VehicleGravity * m_vehicleMass;
+
+            // Hack to reduce downward force if the vehicle is probably sitting on the ground
+            if (ControllingPrim.IsColliding && IsGroundVehicle)
+                appliedGravity *= BSParam.VehicleGroundGravityFudge;
+
+            VehicleAddForce(appliedGravity);
+
+            VDetailLog("{0},  MoveLinear,applyGravity,vehGrav={1},collid={2},fudge={3},mass={4},appliedForce={3}",
+                            ControllingPrim.LocalID, m_VehicleGravity,
+                            ControllingPrim.IsColliding, BSParam.VehicleGroundGravityFudge, m_vehicleMass, appliedGravity);
         }
 
         // =======================================================================
@@ -1079,55 +1266,24 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         //     set directly on the vehicle.
         private void MoveAngular(float pTimestep)
         {
-            // The user wants this many radians per second angular change?
-            Vector3 angularMotorContribution = m_angularMotor.Step(pTimestep);
+            ComputeAngularTurning(pTimestep);
 
-            // ==================================================================
-            // From http://wiki.secondlife.com/wiki/LlSetVehicleFlags :
-            //    This flag prevents linear deflection parallel to world z-axis. This is useful
-            //    for preventing ground vehicles with large linear deflection, like bumper cars,
-            //    from climbing their linear deflection into the sky. 
-            // That is, NO_DEFLECTION_UP says angular motion should not add any pitch or roll movement
-            if ((m_flags & (VehicleFlag.NO_DEFLECTION_UP)) != 0)
-            {
-                angularMotorContribution.X = 0f;
-                angularMotorContribution.Y = 0f;
-                VDetailLog("{0},  MoveAngular,noDeflectionUp,angularMotorContrib={1}", Prim.LocalID, angularMotorContribution);
-            }
-
-            Vector3 verticalAttractionContribution = ComputeAngularVerticalAttraction();
+            ComputeAngularVerticalAttraction();
 
-            Vector3 deflectionContribution = ComputeAngularDeflection();
+            ComputeAngularDeflection();
 
-            Vector3 bankingContribution = ComputeAngularBanking();
+            ComputeAngularBanking();
 
             // ==================================================================
-            m_lastVertAttractor = verticalAttractionContribution;
-
-            m_lastAngularVelocity = angularMotorContribution
-                                    + verticalAttractionContribution
-                                    + deflectionContribution
-                                    + bankingContribution;
-
-            // ==================================================================
-            // Apply the correction velocity.
-            // TODO: Should this be applied as an angular force (torque)?
-            if (!m_lastAngularVelocity.ApproxEquals(Vector3.Zero, 0.01f))
+            if (VehicleRotationalVelocity.ApproxEquals(Vector3.Zero, 0.0001f))
             {
-                VehicleRotationalVelocity = m_lastAngularVelocity;
-
-                VDetailLog("{0},  MoveAngular,done,nonZero,angMotorContrib={1},vertAttrContrib={2},bankContrib={3},deflectContrib={4},totalContrib={5}",
-                                    Prim.LocalID,
-                                    angularMotorContribution, verticalAttractionContribution,
-                                    bankingContribution, deflectionContribution,
-                                    m_lastAngularVelocity
-                                    );
+                // The vehicle is not adding anything angular wise.
+                VehicleRotationalVelocity = Vector3.Zero;
+                VDetailLog("{0},  MoveAngular,done,zero", ControllingPrim.LocalID);
             }
             else
             {
-                // The vehicle is not adding anything angular wise.
-                VehicleRotationalVelocity = Vector3.Zero;
-                VDetailLog("{0},  MoveAngular,done,zero", Prim.LocalID);
+                VDetailLog("{0},  MoveAngular,done,nonZero,angVel={1}", ControllingPrim.LocalID, VehicleRotationalVelocity);
             }
 
             // ==================================================================
@@ -1158,10 +1314,42 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                     torqueFromOffset.Z = 0;
 
                 VehicleAddAngularForce(torqueFromOffset * m_vehicleMass);
-                VDetailLog("{0},  BSDynamic.MoveAngular,motorOffset,applyTorqueImpulse={1}", Prim.LocalID, torqueFromOffset);
+                VDetailLog("{0},  BSDynamic.MoveAngular,motorOffset,applyTorqueImpulse={1}", ControllingPrim.LocalID, torqueFromOffset);
             }
 
         }
+
+        private void ComputeAngularTurning(float pTimestep)
+        {
+            // The user wants this many radians per second angular change?
+            Vector3 currentAngularV = VehicleRotationalVelocity * Quaternion.Inverse(VehicleOrientation);
+            Vector3 angularMotorContributionV = m_angularMotor.Step(pTimestep, currentAngularV);
+
+            // ==================================================================
+            // From http://wiki.secondlife.com/wiki/LlSetVehicleFlags :
+            //    This flag prevents linear deflection parallel to world z-axis. This is useful
+            //    for preventing ground vehicles with large linear deflection, like bumper cars,
+            //    from climbing their linear deflection into the sky.
+            // That is, NO_DEFLECTION_UP says angular motion should not add any pitch or roll movement
+            // TODO: This is here because this is where ODE put it but documentation says it
+            //    is a linear effect. Where should this check go?
+            //if ((m_flags & (VehicleFlag.NO_DEFLECTION_UP)) != 0)
+           // {
+            //    angularMotorContributionV.X = 0f;
+            //    angularMotorContributionV.Y = 0f;
+          //  }
+
+            // Reduce any velocity by friction.
+            Vector3 frictionFactorW = ComputeFrictionFactor(m_angularFrictionTimescale, pTimestep);
+            angularMotorContributionV -= (currentAngularV * frictionFactorW);
+
+            VehicleRotationalVelocity += angularMotorContributionV * VehicleOrientation;
+
+
+
+            VDetailLog("{0},  MoveAngular,angularTurning,angContribV={1}", ControllingPrim.LocalID, angularMotorContributionV);
+        }
+
         // From http://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial:
         //      Some vehicles, like boats, should always keep their up-side up. This can be done by
         //      enabling the "vertical attractor" behavior that springs the vehicle's local z-axis to
@@ -1170,15 +1358,84 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         //      and then set the VEHICLE_VERTICAL_ATTRACTION_EFFICIENCY to control the damping. An
         //      efficiency of 0.0 will cause the spring to wobble around its equilibrium, while an
         //      efficiency of 1.0 will cause the spring to reach its equilibrium with exponential decay.
-        public Vector3 ComputeAngularVerticalAttraction()
+        public void ComputeAngularVerticalAttraction()
         {
-            Vector3 ret = Vector3.Zero;
 
             // If vertical attaction timescale is reasonable
-            if (m_verticalAttractionTimescale < m_verticalAttractionCutoff)
+            if (enableAngularVerticalAttraction && m_verticalAttractionTimescale < m_verticalAttractionCutoff)
             {
+                //Another formula to try got from :
+                //http://answers.unity3d.com/questions/10425/how-to-stabilize-angular-motion-alignment-of-hover.html
+
+                Vector3 VehicleUpAxis = Vector3.UnitZ * VehicleOrientation;
+
+                // Flipping what was originally a timescale into a speed variable and then multiplying it by 2
+                //    since only computing half the distance between the angles.
+                float VerticalAttractionSpeed = (1 / m_verticalAttractionTimescale) * 2.0f;
+
+                // Make a prediction of where the up axis will be when this is applied rather then where it is now as
+                //     this makes for a smoother adjustment and less fighting between the various forces.
+                Vector3 predictedUp = VehicleUpAxis * Quaternion.CreateFromAxisAngle(VehicleRotationalVelocity, 0f);
+
+                // This is only half the distance to the target so it will take 2 seconds to complete the turn.
+                Vector3 torqueVector = Vector3.Cross(predictedUp, Vector3.UnitZ);
+
+                // Scale vector by our timescale since it is an acceleration it is r/s^2 or radians a timescale squared
+                Vector3 vertContributionV = torqueVector * VerticalAttractionSpeed * VerticalAttractionSpeed;
+
+                VehicleRotationalVelocity += vertContributionV;
+
+                VDetailLog("{0},  MoveAngular,verticalAttraction,UpAxis={1},PredictedUp={2},torqueVector={3},contrib={4}",
+                                ControllingPrim.LocalID,
+                                VehicleUpAxis,
+                                predictedUp,
+                                torqueVector,
+                                vertContributionV);
+                //=====================================================================
+                /*
+                // Possible solution derived from a discussion at:
+                // http://stackoverflow.com/questions/14939657/computing-vector-from-quaternion-works-computing-quaternion-from-vector-does-no
+
+                // Create a rotation that is only the vehicle's rotation around Z
+                Vector3 currentEuler = Vector3.Zero;
+                VehicleOrientation.GetEulerAngles(out currentEuler.X, out currentEuler.Y, out currentEuler.Z);
+                Quaternion justZOrientation = Quaternion.CreateFromAxisAngle(Vector3.UnitZ, currentEuler.Z);
+
+                // Create the axis that is perpendicular to the up vector and the rotated up vector.
+                Vector3 differenceAxis = Vector3.Cross(Vector3.UnitZ * justZOrientation, Vector3.UnitZ * VehicleOrientation);
+                // Compute the angle between those to vectors.
+                double differenceAngle = Math.Acos((double)Vector3.Dot(Vector3.UnitZ, Vector3.Normalize(Vector3.UnitZ * VehicleOrientation)));
+                // 'differenceAngle' is the angle to rotate and 'differenceAxis' is the plane to rotate in to get the vehicle vertical
+
+                // Reduce the change by the time period it is to change in. Timestep is handled when velocity is applied.
+                // TODO: add 'efficiency'.
+                differenceAngle /= m_verticalAttractionTimescale;
+
+                // Create the quaterian representing the correction angle
+                Quaternion correctionRotation = Quaternion.CreateFromAxisAngle(differenceAxis, (float)differenceAngle);
+
+                // Turn that quaternion into Euler values to make it into velocities to apply.
+                Vector3 vertContributionV = Vector3.Zero;
+                correctionRotation.GetEulerAngles(out vertContributionV.X, out vertContributionV.Y, out vertContributionV.Z);
+                vertContributionV *= -1f;
+
+                VehicleRotationalVelocity += vertContributionV;
+
+                VDetailLog("{0},  MoveAngular,verticalAttraction,diffAxis={1},diffAng={2},corrRot={3},contrib={4}",
+                                ControllingPrim.LocalID,
+                                differenceAxis,
+                                differenceAngle,
+                                correctionRotation,
+                                vertContributionV);
+                 */
+
+                // ===================================================================
+                /*
+                Vector3 vertContributionV = Vector3.Zero;
+                Vector3 origRotVelW = VehicleRotationalVelocity;        // DEBUG DEBUG
+
                 // Take a vector pointing up and convert it from world to vehicle relative coords.
-                Vector3 verticalError = Vector3.UnitZ * VehicleOrientation;
+                Vector3 verticalError = Vector3.Normalize(Vector3.UnitZ * VehicleOrientation);
 
                 // If vertical attraction correction is needed, the vector that was pointing up (UnitZ)
                 //    is now:
@@ -1190,49 +1447,57 @@ namespace OpenSim.Region.Physics.BulletSPlugin
 
                 // Y error means needed rotation around X axis and visa versa.
                 // Since the error goes from zero to one, the asin is the corresponding angle.
-                ret.X = (float)Math.Asin(verticalError.Y);
+                vertContributionV.X = (float)Math.Asin(verticalError.Y);
                 // (Tilt forward (positive X) needs to tilt back (rotate negative) around Y axis.)
-                ret.Y = -(float)Math.Asin(verticalError.X);
+                vertContributionV.Y = -(float)Math.Asin(verticalError.X);
 
                 // If verticalError.Z is negative, the vehicle is upside down. Add additional push.
                 if (verticalError.Z < 0f)
                 {
-                    ret.X += PIOverFour;
-                    ret.Y += PIOverFour;
+                    vertContributionV.X += Math.Sign(vertContributionV.X) * PIOverFour;
+                    // vertContribution.Y -= PIOverFour;
                 }
 
-                // 'ret' is now the necessary velocity to correct tilt in one second.
+                // 'vertContrbution' is now the necessary angular correction to correct tilt in one second.
                 //     Correction happens over a number of seconds.
-                Vector3 unscaledContrib = ret;
-                ret /= m_verticalAttractionTimescale;
+                Vector3 unscaledContribVerticalErrorV = vertContributionV;     // DEBUG DEBUG
+
+                // The correction happens over the user's time period
+                vertContributionV /= m_verticalAttractionTimescale;
 
-                VDetailLog("{0},  MoveAngular,verticalAttraction,,verticalError={1},unscaled={2},eff={3},ts={4},vertAttr={5}",
-                                Prim.LocalID, verticalError, unscaledContrib, m_verticalAttractionEfficiency, m_verticalAttractionTimescale, ret);
+                // Rotate the vehicle rotation to the world coordinates.
+                VehicleRotationalVelocity += (vertContributionV * VehicleOrientation);
+
+                VDetailLog("{0},  MoveAngular,verticalAttraction,,origRotVW={1},vertError={2},unscaledV={3},eff={4},ts={5},vertContribV={6}",
+                                Prim.LocalID, origRotVelW, verticalError, unscaledContribVerticalErrorV,
+                                m_verticalAttractionEfficiency, m_verticalAttractionTimescale, vertContributionV);
+                */
             }
-            return ret;
         }
 
-        // Return the angular correction to correct the direction the vehicle is pointing to be
+        // Angular correction to correct the direction the vehicle is pointing to be
         //      the direction is should want to be pointing.
         // The vehicle is moving in some direction and correct its orientation to it is pointing
         //     in that direction.
         // TODO: implement reference frame.
-        public Vector3 ComputeAngularDeflection()
+        public void ComputeAngularDeflection()
         {
-            Vector3 ret = Vector3.Zero;
-            return ret;         // DEBUG DEBUG DEBUG
-            // Disable angular deflection for the moment.
             // Since angularMotorUp and angularDeflection are computed independently, they will calculate
             //     approximately the same X or Y correction. When added together (when contributions are combined)
             //     this creates an over-correction and then wabbling as the target is overshot.
             // TODO: rethink how the different correction computations inter-relate.
 
-            if (m_angularDeflectionEfficiency != 0)
+            if (enableAngularDeflection && m_angularDeflectionEfficiency != 0 && VehicleForwardSpeed > 0.2)
             {
+                Vector3 deflectContributionV = Vector3.Zero;
+
                 // The direction the vehicle is moving
                 Vector3 movingDirection = VehicleVelocity;
                 movingDirection.Normalize();
 
+                // If the vehicle is going backward, it is still pointing forward
+                movingDirection *= Math.Sign(VehicleForwardSpeed);
+
                 // The direction the vehicle is pointing
                 Vector3 pointingDirection = Vector3.UnitX * VehicleOrientation;
                 pointingDirection.Normalize();
@@ -1241,6 +1506,9 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 Vector3 deflectionError = movingDirection - pointingDirection;
 
                 // Don't try to correct very large errors (not our job)
+                // if (Math.Abs(deflectionError.X) > PIOverFour) deflectionError.X = PIOverTwo * Math.Sign(deflectionError.X);
+                // if (Math.Abs(deflectionError.Y) > PIOverFour) deflectionError.Y = PIOverTwo * Math.Sign(deflectionError.Y);
+                // if (Math.Abs(deflectionError.Z) > PIOverFour) deflectionError.Z = PIOverTwo * Math.Sign(deflectionError.Z);
                 if (Math.Abs(deflectionError.X) > PIOverFour) deflectionError.X = 0f;
                 if (Math.Abs(deflectionError.Y) > PIOverFour) deflectionError.Y = 0f;
                 if (Math.Abs(deflectionError.Z) > PIOverFour) deflectionError.Z = 0f;
@@ -1248,18 +1516,19 @@ namespace OpenSim.Region.Physics.BulletSPlugin
                 // ret = m_angularDeflectionCorrectionMotor(1f, deflectionError);
 
                 // Scale the correction by recovery timescale and efficiency
-                ret = (-deflectionError) * m_angularDeflectionEfficiency;
-                ret /= m_angularDeflectionTimescale;
+                deflectContributionV = (-deflectionError) * m_angularDeflectionEfficiency;
+                deflectContributionV /= m_angularDeflectionTimescale;
+
+                VehicleRotationalVelocity += deflectContributionV * VehicleOrientation;
 
                 VDetailLog("{0},  MoveAngular,Deflection,movingDir={1},pointingDir={2},deflectError={3},ret={4}",
-                    Prim.LocalID, movingDirection, pointingDirection, deflectionError, ret);
+                    ControllingPrim.LocalID, movingDirection, pointingDirection, deflectionError, deflectContributionV);
                 VDetailLog("{0},  MoveAngular,Deflection,fwdSpd={1},defEff={2},defTS={3}",
-                    Prim.LocalID, VehicleForwardSpeed, m_angularDeflectionEfficiency, m_angularDeflectionTimescale);
+                    ControllingPrim.LocalID, VehicleForwardSpeed, m_angularDeflectionEfficiency, m_angularDeflectionTimescale);
             }
-            return ret;
         }
 
-        // Return an angular change to rotate the vehicle around the Z axis when the vehicle
+        // Angular change to rotate the vehicle around the Z axis when the vehicle
         //     is tipped around the X axis.
         // From http://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial:
         //      The vertical attractor feature must be enabled in order for the banking behavior to
@@ -1267,13 +1536,13 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         //      produce a angular velocity around the yaw-axis, causing the vehicle to turn. The magnitude
         //      of the yaw effect will be proportional to the
         //          VEHICLE_BANKING_EFFICIENCY, the angle of the roll rotation, and sometimes the vehicle's
-        //                 velocity along its preferred axis of motion. 
+        //                 velocity along its preferred axis of motion.
         //          The VEHICLE_BANKING_EFFICIENCY can vary between -1 and +1. When it is positive then any
         //                  positive rotation (by the right-hand rule) about the roll-axis will effect a
         //                  (negative) torque around the yaw-axis, making it turn to the right--that is the
         //                  vehicle will lean into the turn, which is how real airplanes and motorcycle's work.
         //                  Negating the banking coefficient will make it so that the vehicle leans to the
-        //                  outside of the turn (not very "physical" but might allow interesting vehicles so why not?). 
+        //                  outside of the turn (not very "physical" but might allow interesting vehicles so why not?).
         //           The VEHICLE_BANKING_MIX is a fake (i.e. non-physical) parameter that is useful for making
         //                  banking vehicles do what you want rather than what the laws of physics allow.
         //                  For example, consider a real motorcycle...it must be moving forward in order for
@@ -1285,46 +1554,44 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         //                  totally static (0.0) and totally dynamic (1.0). By "static" we mean that the
         //                  banking effect depends only on the vehicle's rotation about its roll-axis compared
         //                  to "dynamic" where the banking is also proportional to its velocity along its
-        //                  roll-axis. Finding the best value of the "mixture" will probably require trial and error. 
+        //                  roll-axis. Finding the best value of the "mixture" will probably require trial and error.
         //      The time it takes for the banking behavior to defeat a preexisting angular velocity about the
         //      world z-axis is determined by the VEHICLE_BANKING_TIMESCALE. So if you want the vehicle to
         //      bank quickly then give it a banking timescale of about a second or less, otherwise you can
-        //      make a sluggish vehicle by giving it a timescale of several seconds. 
-        public Vector3 ComputeAngularBanking()
+        //      make a sluggish vehicle by giving it a timescale of several seconds.
+        public void ComputeAngularBanking()
         {
-            Vector3 ret = Vector3.Zero;
-
-            if (m_bankingEfficiency != 0 && m_verticalAttractionTimescale < m_verticalAttractionCutoff)
+            if (enableAngularBanking && m_bankingEfficiency != 0 && m_verticalAttractionTimescale < m_verticalAttractionCutoff)
             {
-                // This works by rotating a unit vector to the orientation of the vehicle. The
-                //    roll (tilt) will be Y component of a tilting Z vector (zero for no tilt
-                //    up to one for full over).
+                Vector3 bankingContributionV = Vector3.Zero;
+
+                // Rotate a UnitZ vector (pointing up) to how the vehicle is oriented.
+                // As the vehicle rolls to the right or left, the Y value will increase from
+                //     zero (straight up) to 1 or -1 (full tilt right  or left)
                 Vector3 rollComponents = Vector3.UnitZ * VehicleOrientation;
 
                 // Figure out the yaw value for this much roll.
-                float turnComponent = rollComponents.Y * rollComponents.Y * m_bankingEfficiency;
-                // Keep the sign
-                if (rollComponents.Y < 0f)
-                    turnComponent = -turnComponent;
-
-                // TODO: there must be a better computation of the banking force.
-                float bankingTurnForce = turnComponent;
-
+                float yawAngle = m_angularMotorDirection.X * m_bankingEfficiency;
                 //        actual error  =       static turn error            +           dynamic turn error
-                float mixedBankingError = bankingTurnForce * (1f - m_bankingMix) + bankingTurnForce * m_bankingMix * VehicleForwardSpeed;
+                float mixedYawAngle =(yawAngle * (1f - m_bankingMix)) + ((yawAngle * m_bankingMix) * VehicleForwardSpeed);
+
                 // TODO: the banking effect should not go to infinity but what to limit it to?
-                mixedBankingError = ClampInRange(-20f, mixedBankingError, 20f);
+                //     And what should happen when this is being added to a user defined yaw that is already PI*4?
+                mixedYawAngle = ClampInRange(-12, mixedYawAngle, 12);
 
                 // Build the force vector to change rotation from what it is to what it should be
-                ret.Z = -mixedBankingError;
+                bankingContributionV.Z = -mixedYawAngle;
+
+                // Don't do it all at once. Fudge because 1 second is too fast with most user defined roll as PI*4.
+                bankingContributionV /= m_bankingTimescale * BSParam.VehicleAngularBankingTimescaleFudge;
 
-                // Don't do it all at once.
-                ret /= m_bankingTimescale;
+                //VehicleRotationalVelocity += bankingContributionV * VehicleOrientation;
+                VehicleRotationalVelocity += bankingContributionV;
 
-                VDetailLog("{0},  MoveAngular,Banking,rollComp={1},speed={2},turnComp={3},bankErr={4},mixedBankErr={5},ret={6}",
-                            Prim.LocalID, rollComponents, VehicleForwardSpeed, turnComponent, bankingTurnForce, mixedBankingError, ret);
+
+                VDetailLog("{0},  MoveAngular,Banking,rollComp={1},speed={2},rollComp={3},yAng={4},mYAng={5},ret={6}",
+                            ControllingPrim.LocalID, rollComponents, VehicleForwardSpeed, rollComponents, yawAngle, mixedYawAngle, bankingContributionV);
             }
-            return ret;
         }
 
         // This is from previous instantiations of XXXDynamics.cs.
@@ -1362,11 +1629,28 @@ namespace OpenSim.Region.Physics.BulletSPlugin
             if (rotq != m_rot)
             {
                 VehicleOrientation = m_rot;
-                VDetailLog("{0},  LimitRotation,done,orig={1},new={2}", Prim.LocalID, rotq, m_rot);
+                VDetailLog("{0},  LimitRotation,done,orig={1},new={2}", ControllingPrim.LocalID, rotq, m_rot);
             }
 
         }
 
+        // Given a friction vector (reduction in seconds) and a timestep, return the factor to reduce
+        //     some value by to apply this friction.
+        private Vector3 ComputeFrictionFactor(Vector3 friction, float pTimestep)
+        {
+            Vector3 frictionFactor = Vector3.Zero;
+            if (friction != BSMotor.InfiniteVector)
+            {
+                // frictionFactor = (Vector3.One / FrictionTimescale) * timeStep;
+                // Individual friction components can be 'infinite' so compute each separately.
+                frictionFactor.X = (friction.X == BSMotor.Infinite) ? 0f : (1f / friction.X);
+                frictionFactor.Y = (friction.Y == BSMotor.Infinite) ? 0f : (1f / friction.Y);
+                frictionFactor.Z = (friction.Z == BSMotor.Infinite) ? 0f : (1f / friction.Z);
+                frictionFactor *= pTimestep;
+            }
+            return frictionFactor;
+        }
+
         private float ClampInRange(float low, float val, float high)
         {
             return Math.Max(low, Math.Min(val, high));
@@ -1376,8 +1660,8 @@ namespace OpenSim.Region.Physics.BulletSPlugin
         // Invoke the detailed logger and output something if it's enabled.
         private void VDetailLog(string msg, params Object[] args)
         {
-            if (Prim.PhysicsScene.VehicleLoggingEnabled)
-                Prim.PhysicsScene.DetailLog(msg, args);
+            if (ControllingPrim.PhysScene.VehicleLoggingEnabled)
+                ControllingPrim.PhysScene.DetailLog(msg, args);
         }
     }
 }