public void setGravity(btVector3 v)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_BtDynamicsWorld_setGravity(m_handle,v.Handle);
        }

        public void applyImpulse(btVector3 force, btVector3 rel_pos)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_BtRigidBody_applyImpulse(m_handle, force.Handle, rel_pos.Handle);
        }

        public bool isInside(btVector3 pt, float tolerance)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            return BulletAPI_BtBoxShape_isInside(m_handle, pt.Handle, tolerance);
        }

        public void setAngularLowerLimit(btVector3 linearLower)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_BtGeneric6DofConstraint_setAngularLowerLimit(m_handle, linearLower.Handle);
        }

        public int findOrAddVertex(btVector3 vertex, bool removeDuplicateVertices)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            return BulletAPI_BtTriangleMesh_findOrAddVertex(m_handle, vertex.Handle, removeDuplicateVertices);
        }

        public void applyCentralForce(btVector3 force)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_BtRigidBody_applyCentralForce(m_handle, force.Handle);
        }

        public void rayTest(btVector3 rayFromWorld, btVector3 rayToWorld, btRayResultCallback resultCallback)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_btCollisionWorld_rayTest(m_handle, rayFromWorld.Handle, rayToWorld.Handle, resultCallback.Handle);
        }

        public void addTriangle( btVector3 vertex0, btVector3 vertex1, btVector3 vertex2, bool removeDuplicates)
        {
            if (m_disposed)
                throw new ObjectDisposedException(ToString());

            BulletAPI_BtTriangleMesh_addTriangle(m_handle, vertex0.Handle, vertex1.Handle, vertex2.Handle,
                                                 removeDuplicates);
        }

 public btRigidBody(float mass, btMotionState motionState, btCollisionShape collisionShape, btVector3 localInertia)
 {
     
     m_constructionInfo = new btRigidBodyConstructionInfo();
     m_constructionInfo.m_collisionShape = collisionShape;
     m_constructionInfo.m_localInertia = localInertia;
     m_constructionInfo.m_motionState = motionState;
     m_constructionInfo.m_startWorldTransform = btTransform.getIdentity();
     m_constructionInfo.SetGenericDefaultValues();
     m_constructionInfo.m_mass = mass;
     m_constructionInfo.commit();
     m_handle = BulletAPI_CreateBtRigidBody(m_constructionInfo.Handle);
  }

        private void changeAddAngularForce(float timestep)
        {
            if (!m_isSelected)
            {
                lock (m_angularforcelist)
                {
                    //m_log.Info("[PHYSICS]: dequeing forcelist");
                    if (IsPhysical)
                    {
                        Vector3 iforce = Vector3.Zero;
                        for (int i = 0; i < m_angularforcelist.Count; i++)
                        {
                            iforce = iforce + m_angularforcelist[i];
                        }

                        if (Body != null && Body.Handle != IntPtr.Zero)
                        {
                            if (tempAddForce != null && tempAddForce.Handle != IntPtr.Zero)
                                tempAddForce.Dispose();
                            enableBodySoft();
                            tempAddForce = new btVector3(iforce.X, iforce.Y, iforce.Z);
                            Body.applyTorqueImpulse(tempAddForce);
                        }

                    }
                    m_angularforcelist.Clear();
                }

                m_collisionscore = 0;
                m_interpenetrationcount = 0;
            }

            m_taintaddangularforce = false;
        }

        public override void SetTerrain(float[] heightMap, double[,] normalHeightMap)
        {
            if (m_terrainShape != null)
                DeleteTerrain();

            float hfmax = -9000;
            float hfmin = 90000;
            
            for (int i = 0; i <heightMap.Length;i++)
            {
                if (Single.IsNaN(heightMap[i]) || Single.IsInfinity(heightMap[i]))
                {
                    heightMap[i] = 0f;
                }

                hfmin = (heightMap[i] < hfmin) ? heightMap[i] : hfmin;
                hfmax = (heightMap[i] > hfmax) ? heightMap[i] : hfmax;
            }
            // store this for later reference.
            // Note, we're storing it  after we check it for anomolies above
            _origheightmap = heightMap;

            hfmin = 0;
            hfmax = 256;

            m_terrainShape = new btHeightfieldTerrainShape((int)Constants.RegionSize, (int)Constants.RegionSize, heightMap,
                                                           1.0f, hfmin, hfmax, (int)btHeightfieldTerrainShape.UPAxis.Z,
                                                           (int)btHeightfieldTerrainShape.PHY_ScalarType.PHY_FLOAT, false);
            float AabbCenterX = Constants.RegionSize/2f;
            float AabbCenterY = Constants.RegionSize/2f;

            float AabbCenterZ = 0;
            float temphfmin, temphfmax;

            temphfmin = hfmin;
            temphfmax = hfmax;

            if (temphfmin < 0)
            {
                temphfmax = 0 - temphfmin;
                temphfmin = 0 - temphfmin;
            }
            else if (temphfmin > 0)
            {
                temphfmax = temphfmax + (0 - temphfmin);
                //temphfmin = temphfmin + (0 - temphfmin);
            }
            AabbCenterZ = temphfmax/2f;
            
            if (m_terrainPosition == null)
            {
                m_terrainPosition = new btVector3(AabbCenterX, AabbCenterY, AabbCenterZ);
            }
            else
            {
                try
                {
                    m_terrainPosition.setValue(AabbCenterX, AabbCenterY, AabbCenterZ);
                } 
                catch (ObjectDisposedException)
                {
                    m_terrainPosition = new btVector3(AabbCenterX, AabbCenterY, AabbCenterZ);
                }
            }
            if (m_terrainMotionState != null)
            {
                m_terrainMotionState.Dispose();
                m_terrainMotionState = null;
            }
            m_terrainTransform = new btTransform(QuatIdentity, m_terrainPosition);
            m_terrainMotionState = new btDefaultMotionState(m_terrainTransform);
            TerrainBody = new btRigidBody(0, m_terrainMotionState, m_terrainShape);
            TerrainBody.setUserPointer((IntPtr)0);
            m_world.addRigidBody(TerrainBody);
        }

        public void SetBody(float mass)
        {

            if (!IsPhysical || childrenPrim.Count == 0)
            {
                if (tempMotionState1 != null && tempMotionState1.Handle != IntPtr.Zero)
                    tempMotionState1.Dispose();
                if (tempTransform2 != null && tempTransform2.Handle != IntPtr.Zero)
                    tempTransform2.Dispose();
                if (tempOrientation2 != null && tempOrientation2.Handle != IntPtr.Zero)
                    tempOrientation2.Dispose();

                if (tempPosition2 != null && tempPosition2.Handle != IntPtr.Zero)
                    tempPosition2.Dispose();

                tempOrientation2 = new btQuaternion(_orientation.X, _orientation.Y, _orientation.Z, _orientation.W);
                tempPosition2 = new btVector3(_position.X, _position.Y, _position.Z);
                tempTransform2 = new btTransform(tempOrientation2, tempPosition2);
                tempMotionState1 = new btDefaultMotionState(tempTransform2, _parent_scene.TransZero);
                if (tempInertia1 != null && tempInertia1.Handle != IntPtr.Zero)
                    tempInertia1.Dispose();
                tempInertia1 = new btVector3(0, 0, 0);


                prim_geom.calculateLocalInertia(mass, tempInertia1);

                if (mass != 0)
                    _parent_scene.addActivePrim(this);
                else
                    _parent_scene.remActivePrim(this);

                //     Body = new btRigidBody(mass, tempMotionState1, prim_geom);
                //else
                Body = new btRigidBody(mass, tempMotionState1, prim_geom, tempInertia1);

                if (prim_geom is btGImpactMeshShape)
                {
                    ((btGImpactMeshShape)prim_geom).setLocalScaling(new btVector3(1, 1, 1));
                    ((btGImpactMeshShape)prim_geom).updateBound();
                }
                //Body.setCollisionFlags(Body.getCollisionFlags() | (int)ContactFlags.CF_CUSTOM_MATERIAL_CALLBACK);
                //Body.setUserPointer((IntPtr) (int)m_localID);
                _parent_scene.AddPrimToScene(this);
            }
            else
            {
                // bool hasTrimesh = false;
                lock (childrenPrim)
                {
                    foreach (BulletDotNETPrim chld in childrenPrim)
                    {
                        if (chld == null)
                            continue;

                        // if (chld.NeedsMeshing())
                        //     hasTrimesh = true;
                    }
                }

                //if (hasTrimesh)
                //{
                ProcessGeomCreationAsTriMesh(Vector3.Zero, Quaternion.Identity);
                // createmesh returns null when it doesn't mesh.

                /*
                if (_mesh is Mesh)
                {
                }
                else
                {
                    m_log.Warn("[PHYSICS]: Can't link a OpenSim.Region.Physics.Meshing.Mesh object");
                    return;
                }
                */



                foreach (BulletDotNETPrim chld in childrenPrim)
                {
                    if (chld == null)
                        continue;
                    Vector3 offset = chld.Position - Position;
                    Vector3 pos = new Vector3(offset.X, offset.Y, offset.Z);
                    pos *= Quaternion.Inverse(Orientation);
                    //pos *= Orientation;
                    offset = pos;
                    chld.ProcessGeomCreationAsTriMesh(offset, chld.Orientation);

                    _mesh.Append(chld._mesh);


                }
                setMesh(_parent_scene, _mesh);

                //}

                if (tempMotionState1 != null && tempMotionState1.Handle != IntPtr.Zero)
                    tempMotionState1.Dispose();
                if (tempTransform2 != null && tempTransform2.Handle != IntPtr.Zero)
                    tempTransform2.Dispose();
//.........这里部分代码省略.........

 public BulletDotNETScene(string sceneIdentifier)
 {
     BulletLock = new object();
     // m_sceneIdentifier = sceneIdentifier;
     VectorZero = new btVector3(0, 0, 0);
     QuatIdentity = new btQuaternion(0, 0, 0, 1);
     TransZero = new btTransform(QuatIdentity, VectorZero);
     m_gravity = new btVector3(0, 0, gravityz);
 }

        /// <summary>
        /// This creates the Avatar's physical Surrogate at the position supplied
        /// </summary>
        /// <param name="npositionX"></param>
        /// <param name="npositionY"></param>
        /// <param name="npositionZ"></param>

        // WARNING: This MUST NOT be called outside of ProcessTaints, else we can have unsynchronized access
        // to ODE internals. ProcessTaints is called from within thread-locked Simulate(), so it is the only 
        // place that is safe to call this routine AvatarGeomAndBodyCreation.
        private void AvatarGeomAndBodyCreation(float npositionX, float npositionY, float npositionZ)
        {
            
            if (CAPSULE_LENGTH <= 0)
            {
                m_log.Warn("[PHYSICS]: The capsule size you specified in opensim.ini is invalid!  Setting it to the smallest possible size!");
                CAPSULE_LENGTH = 0.01f;

            }

            if (CAPSULE_RADIUS <= 0)
            {
                m_log.Warn("[PHYSICS]: The capsule size you specified in opensim.ini is invalid!  Setting it to the smallest possible size!");
                CAPSULE_RADIUS = 0.01f;

            }

            Shell = new btCapsuleShape(CAPSULE_RADIUS, CAPSULE_LENGTH);

            if (m_bodyPosition == null)
                m_bodyPosition = new btVector3(npositionX, npositionY, npositionZ);

            m_bodyPosition.setValue(npositionX, npositionY, npositionZ);

            if (m_bodyOrientation == null)
                m_bodyOrientation = new btQuaternion(m_CapsuleOrientationAxis, (Utils.DEG_TO_RAD * 90));

            if (m_bodyTransform == null)
                m_bodyTransform = new btTransform(m_bodyOrientation, m_bodyPosition);
            else
            {
                m_bodyTransform.Dispose();
                m_bodyTransform = new btTransform(m_bodyOrientation, m_bodyPosition);
            }

            if (m_bodyMotionState == null)
                m_bodyMotionState = new btDefaultMotionState(m_bodyTransform);
            else
                m_bodyMotionState.setWorldTransform(m_bodyTransform);

            m_mass = Mass;

            Body = new btRigidBody(m_mass, m_bodyMotionState, Shell);
            // this is used for self identification. User localID instead of body handle
            Body.setUserPointer(new IntPtr((int)m_localID));
            
            if (ClosestCastResult != null)
                ClosestCastResult.Dispose();
            ClosestCastResult = new ClosestNotMeRayResultCallback(Body);

            m_parent_scene.AddRigidBody(Body);
            Body.setActivationState(4);
            if (m_aMotor != null)
            {
                if (m_aMotor.Handle != IntPtr.Zero)
                {
                    m_parent_scene.getBulletWorld().removeConstraint(m_aMotor);
                    m_aMotor.Dispose();
                }
                m_aMotor = null;
            }

            m_aMotor = new btGeneric6DofConstraint(Body, m_parent_scene.TerrainBody,
                                                                         m_parent_scene.TransZero,
                                                                         m_parent_scene.TransZero, false);
            m_aMotor.setAngularLowerLimit(m_parent_scene.VectorZero);
            m_aMotor.setAngularUpperLimit(m_parent_scene.VectorZero);
            
           
        }

 public btBoxShape(btVector3 boxHalfExtents)
     : base()
 {
     m_handle = BulletAPI_CreateBtBoxShape(boxHalfExtents.Handle);
 }

        public BulletDotNETPrim(String primName, BulletDotNETScene parent_scene, Vector3 pos, Vector3 size,
                       Quaternion rotation, IMesh mesh, PrimitiveBaseShape pbs, bool pisPhysical)
        {
            tempPosition1 = new btVector3(0, 0, 0);
            tempPosition2 = new btVector3(0, 0, 0);
            tempPosition3 = new btVector3(0, 0, 0);
            tempSize1 = new btVector3(0, 0, 0);
            tempSize2 = new btVector3(0, 0, 0);
            tempLinearVelocity1 = new btVector3(0, 0, 0);
            tempLinearVelocity2 = new btVector3(0, 0, 0);
            tempAngularVelocity1 = new btVector3(0, 0, 0);
            tempAngularVelocity2 = new btVector3(0, 0, 0);
            tempInertia1 = new btVector3(0, 0, 0);
            tempInertia2 = new btVector3(0, 0, 0);
            tempOrientation1 = new btQuaternion(0, 0, 0, 1);
            tempOrientation2 = new btQuaternion(0, 0, 0, 1);
            _parent_scene = parent_scene;
            tempTransform1 = new btTransform(_parent_scene.QuatIdentity, _parent_scene.VectorZero);
            tempTransform2 = new btTransform(_parent_scene.QuatIdentity, _parent_scene.VectorZero); ;
            tempTransform3 = new btTransform(_parent_scene.QuatIdentity, _parent_scene.VectorZero); ;
            tempTransform4 = new btTransform(_parent_scene.QuatIdentity, _parent_scene.VectorZero); ;

            tempMotionState1 = new btDefaultMotionState(_parent_scene.TransZero);
            tempMotionState2 = new btDefaultMotionState(_parent_scene.TransZero);
            tempMotionState3 = new btDefaultMotionState(_parent_scene.TransZero);


            AxisLockLinearLow = new btVector3(-1 * (int)Constants.RegionSize, -1 * (int)Constants.RegionSize, -1 * (int)Constants.RegionSize);
            int regionsize = (int)Constants.RegionSize;

            if (regionsize == 256)
                regionsize = 512;

            AxisLockLinearHigh = new btVector3((int)Constants.RegionSize, (int)Constants.RegionSize, (int)Constants.RegionSize);

            _target_velocity = Vector3.Zero;
            _velocity = Vector3.Zero;
            _position = pos;
            m_taintposition = pos;
            PID_D = parent_scene.bodyPIDD;
            PID_G = parent_scene.bodyPIDG;
            m_density = parent_scene.geomDefaultDensity;
            // m_tensor = parent_scene.bodyMotorJointMaxforceTensor;
            // body_autodisable_frames = parent_scene.bodyFramesAutoDisable;

            prim_geom = null;
            Body = null;

            if (size.X <= 0) size.X = 0.01f;
            if (size.Y <= 0) size.Y = 0.01f;
            if (size.Z <= 0) size.Z = 0.01f;

            _size = size;
            m_taintsize = _size;
            _acceleration = Vector3.Zero;
            m_rotationalVelocity = Vector3.Zero;
            _orientation = rotation;
            m_taintrot = _orientation;
            _mesh = mesh;
            _pbs = pbs;

            _parent_scene = parent_scene;

            if (pos.Z < 0)
                m_isphysical = false;
            else
            {
                m_isphysical = pisPhysical;
                // If we're physical, we need to be in the master space for now.
                // linksets *should* be in a space together..  but are not currently
            }
            m_primName = primName;
            m_taintadd = true;
            _parent_scene.AddPhysicsActorTaint(this);

        }

        internal void EnableAxisMotor(Vector3 axislock)
        {
            if (m_aMotor != null)
                DisableAxisMotor();

            if (Body == null)
                return;

            if (Body.Handle == IntPtr.Zero)
                return;

            if (AxisLockAngleHigh != null && AxisLockAngleHigh.Handle != IntPtr.Zero)
                AxisLockAngleHigh.Dispose();



            m_aMotor = new btGeneric6DofConstraint(Body, _parent_scene.TerrainBody, _parent_scene.TransZero,
                                                   _parent_scene.TransZero, false);

            float endNoLock = (360 * Utils.DEG_TO_RAD);
            AxisLockAngleHigh = new btVector3((axislock.X == 0) ? 0 : endNoLock, (axislock.Y == 0) ? 0 : endNoLock, (axislock.Z == 0) ? 0 : endNoLock);

            m_aMotor.setAngularLowerLimit(_parent_scene.VectorZero);
            m_aMotor.setAngularUpperLimit(AxisLockAngleHigh);
            m_aMotor.setLinearLowerLimit(AxisLockLinearLow);
            m_aMotor.setLinearUpperLimit(AxisLockLinearHigh);
            _parent_scene.getBulletWorld().addConstraint((btTypedConstraint)m_aMotor);
            //m_aMotor.


        }

//.........这里部分代码省略.........
                            }
                            else
                            {
                                m_targetHoverHeight = m_waterHeight + m_PIDHoverHeight;
                            }
                            break;
                        case PIDHoverType.Water:
                            m_waterHeight = _parent_scene.GetWaterLevel();
                            m_targetHoverHeight = m_waterHeight + m_PIDHoverHeight;
                            break;
                    }


                    _target_velocity =
                        new Vector3(0.0f, 0.0f,
                            (m_targetHoverHeight - pos.Z) * ((PID_G - m_PIDHoverTau) * timestep)
                            );

                    //  if velocity is zero, use position control; otherwise, velocity control

                    if (_target_velocity.ApproxEquals(Vector3.Zero, 0.1f))
                    {

                        /* TODO: Do Bullet Equiv
                        d.BodySetPosition(Body, pos.X, pos.Y, m_targetHoverHeight);
                        d.BodySetLinearVel(Body, vel.X, vel.Y, 0);
                        d.BodyAddForce(Body, 0, 0, fz);
                        */
                        if (Body != null && Body.Handle != IntPtr.Zero)
                        {
                            Body.setLinearVelocity(_parent_scene.VectorZero);
                            Body.clearForces();
                        }
                        return;
                    }
                    else
                    {
                        _zeroFlag = false;

                        // We're flying and colliding with something
                        fz = fz + ((_target_velocity.Z - vel.Z) * (PID_D) * m_mass);
                    }
                }

                fx *= m_mass;
                fy *= m_mass;
                //fz *= m_mass;

                fx += m_force.X;
                fy += m_force.Y;
                fz += m_force.Z;

                //m_log.Info("[OBJPID]: X:" + fx.ToString() + " Y:" + fy.ToString() + " Z:" + fz.ToString());
                if (fx != 0 || fy != 0 || fz != 0)
                {
                    /*
                     * TODO: Do Bullet Equiv
                    if (!d.BodyIsEnabled(Body))
                    {
                        d.BodySetLinearVel(Body, 0f, 0f, 0f);
                        d.BodySetForce(Body, 0, 0, 0);
                        enableBodySoft();
                    }
                    */
                    // 35x10 = 350n times the mass per second applied maximum.

                    float nmax = 35f * m_mass;
                    float nmin = -35f * m_mass;


                    if (fx > nmax)
                        fx = nmax;
                    if (fx < nmin)
                        fx = nmin;
                    if (fy > nmax)
                        fy = nmax;
                    if (fy < nmin)
                        fy = nmin;

                    // TODO: Do Bullet Equiv
                    // d.BodyAddForce(Body, fx, fy, fz);
                    if (Body != null && Body.Handle != IntPtr.Zero)
                    {
                        Body.activate(true);
                        if (tempAddForce != null && tempAddForce.Handle != IntPtr.Zero)
                            tempAddForce.Dispose();

                        tempAddForce = new btVector3(fx * 0.01f, fy * 0.01f, fz * 0.01f);
                        Body.applyCentralImpulse(tempAddForce);
                    }
                }
            }
            else
            {
                if (m_zeroPosition == null)
                    m_zeroPosition = Vector3.Zero;
                m_zeroPosition = _position;
                return;
            }
        }

        public BulletDotNETCharacter(string avName, BulletDotNETScene parent_scene, Vector3 pos, Vector3 size, float pid_d, float pid_p, float capsule_radius, float tensor, float density, float height_fudge_factor, float walk_divisor, float rundivisor)
        {
            m_position = pos;
            m_zeroPosition = pos;
            m_parent_scene = parent_scene;
            PID_D = pid_d;
            PID_P = pid_p;
            CAPSULE_RADIUS = capsule_radius;
            m_density = density;
            heightFudgeFactor = height_fudge_factor;
            walkDivisor = walk_divisor;
            runDivisor = rundivisor;
            
            for (int i = 0; i < 11; i++)
            {
                m_colliderarr[i] = false;
            }
            for (int i = 0; i < 11; i++)
            {
                m_colliderGroundarr[i] = false;
            }
            CAPSULE_LENGTH = (size.Z * 1.15f) - CAPSULE_RADIUS * 2.0f;
            m_tainted_CAPSULE_LENGTH = CAPSULE_LENGTH;
            m_isPhysical = false; // current status: no ODE information exists
            m_tainted_isPhysical = true; // new tainted status: need to create ODE information

            m_parent_scene.AddPhysicsActorTaint(this);
            
            // m_name = avName;
            tempVector1 = new btVector3(0, 0, 0);
            tempVector2 = new btVector3(0, 0, 0);
            tempVector3 = new btVector3(0, 0, 0);
            tempVector4 = new btVector3(0, 0, 0);

            tempVector5RayCast = new btVector3(0, 0, 0);
            tempVector6RayCast = new btVector3(0, 0, 0);
            tempVector7RayCast = new btVector3(0, 0, 0);

            tempQuat1 = new btQuaternion(0, 0, 0, 1);
            tempTrans1 = new btTransform(tempQuat1, tempVector1);
            // m_movementComparision = new PhysicsVector(0, 0, 0);
            m_CapsuleOrientationAxis = new btVector3(1, 0, 1);
        }

        public override void SetTerrain (ITerrainChannel channel, short[] shortheightMap)
        {
            if (m_terrainShape != null)
                DeleteTerrain();

            float hfmax = 256;
            float hfmin = 0;
            
            // store this for later reference.
            // Note, we're storing it  after we check it for anomolies above
            _origheightmap = shortheightMap;

            hfmin = 0;
            hfmax = 256;

            float[] heightmap = new float[m_region.RegionSizeX * m_region.RegionSizeX];
            for (int i = 0; i < shortheightMap.Length; i++)
            {
                heightmap[i] = shortheightMap[i] / Constants.TerrainCompression;
            }

            m_terrainShape = new btHeightfieldTerrainShape(m_region.RegionSizeX, m_region.RegionSizeY, heightmap,
                                                           1.0f, hfmin, hfmax, (int)btHeightfieldTerrainShape.UPAxis.Z,
                                                           (int)btHeightfieldTerrainShape.PHY_ScalarType.PHY_FLOAT, false);
            float AabbCenterX = m_region.RegionSizeX / 2f;
            float AabbCenterY = m_region.RegionSizeY / 2f;

            float AabbCenterZ = 0;
            float temphfmin, temphfmax;

            temphfmin = hfmin;
            temphfmax = hfmax;

            if (temphfmin < 0)
            {
                temphfmax = 0 - temphfmin;
                temphfmin = 0 - temphfmin;
            }
            else if (temphfmin > 0)
            {
                temphfmax = temphfmax + (0 - temphfmin);
                //temphfmin = temphfmin + (0 - temphfmin);
            }
            AabbCenterZ = temphfmax/2f;
            
            if (m_terrainPosition == null)
            {
                m_terrainPosition = new btVector3(AabbCenterX, AabbCenterY, AabbCenterZ);
            }
            else
            {
                try
                {
                    m_terrainPosition.setValue(AabbCenterX, AabbCenterY, AabbCenterZ);
                } 
                catch (ObjectDisposedException)
                {
                    m_terrainPosition = new btVector3(AabbCenterX, AabbCenterY, AabbCenterZ);
                }
            }
            if (m_terrainMotionState != null)
            {
                m_terrainMotionState.Dispose();
                m_terrainMotionState = null;
            }
            m_terrainTransform = new btTransform(QuatIdentity, m_terrainPosition);
            m_terrainMotionState = new btDefaultMotionState(m_terrainTransform);
            TerrainBody = new btRigidBody(0, m_terrainMotionState, m_terrainShape);
            TerrainBody.setUserPointer((IntPtr)0);
            m_world.addRigidBody(TerrainBody);
        }