/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSimulator Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
using System;
using System.ComponentModel;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Xml;
using System.Xml.Serialization;
using OpenMetaverse;
using OpenMetaverse.Packets;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Physics.Manager;
using OpenSim.Region.Framework.Scenes.Serialization;

namespace OpenSim.Region.Framework.Scenes
{
    
    [Flags]
    public enum scriptEvents
    {
        None = 0,
        attach = 1,
        collision = 16,
        collision_end = 32,
        collision_start = 64,
        control = 128,
        dataserver = 256,
        email = 512,
        http_response = 1024,
        land_collision = 2048,
        land_collision_end = 4096,
        land_collision_start = 8192,
        at_target = 16384,
        at_rot_target = 16777216,
        listen = 32768,
        money = 65536,
        moving_end = 131072,
        moving_start = 262144,
        not_at_rot_target = 524288,
        not_at_target = 1048576,
        remote_data = 8388608,
        run_time_permissions = 268435456,
        state_entry = 1073741824,
        state_exit = 2,
        timer = 4,
        touch = 8,
        touch_end = 536870912,
        touch_start = 2097152,
        object_rez = 4194304
    }

    struct scriptPosTarget
    {
        public Vector3 targetPos;
        public float tolerance;
        public uint handle;
    }

    struct scriptRotTarget
    {
        public Quaternion targetRot;
        public float tolerance;
        public uint handle;
    }

    public delegate void PrimCountTaintedDelegate();

    /// <summary>
    /// A scene object group is conceptually an object in the scene.  The object is constituted of SceneObjectParts
    /// (often known as prims), one of which is considered the root part.
    /// </summary>
    public partial class SceneObjectGroup : EntityBase, ISceneObject
    {
        // Axis selection bitmask used by SetAxisRotation()
        // Just happen to be the same bits used by llSetStatus() and defined in ScriptBaseClass.
        public enum axisSelect : int
        {
            STATUS_ROTATE_X = 0x002,
            STATUS_ROTATE_Y = 0x004,
            STATUS_ROTATE_Z = 0x008,
        }

        // private PrimCountTaintedDelegate handlerPrimCountTainted = null;

        /// <summary>
        /// Signal whether the non-inventory attributes of any prims in the group have changed
        /// since the group's last persistent backup
        /// </summary>
        private bool m_hasGroupChanged = false;
        private long timeFirstChanged = 0;
        private long timeLastChanged = 0;
        private long m_maxPersistTime = 0;
        private long m_minPersistTime = 0;
//        private Random m_rand;
        private List<ScenePresence> m_linkedAvatars = new List<ScenePresence>();

        /// <summary>
        /// This indicates whether the object has changed such that it needs to be repersisted to permenant storage
        /// (the database).
        /// </summary>
        /// <remarks>
        /// Ultimately, this should be managed such that region modules can change it at the end of a set of operations
        /// so that either all changes are preserved or none at all.  However, currently, a large amount of internal
        /// code will set this anyway when some object properties are changed.
        /// </remarks>
        public bool HasGroupChanged
        {
            set
            {
                if (value)
                {
                    
                    if (m_isBackedUp)
                    {
                        m_scene.SceneGraph.FireChangeBackup(this);
                    }
                    timeLastChanged = DateTime.Now.Ticks;
                    if (!m_hasGroupChanged)
                        timeFirstChanged = DateTime.Now.Ticks;
                    if (m_rootPart != null && m_rootPart.UUID != null && m_scene != null)
                    {
/*
                        if (m_rand == null)
                        {
                            byte[] val = new byte[16];
                            m_rootPart.UUID.ToBytes(val, 0);
                            m_rand = new Random(BitConverter.ToInt32(val, 0));
                        }
 */
                        if (m_scene.GetRootAgentCount() == 0)
                        {
                            //If the region is empty, this change has been made by an automated process
                            //and thus we delay the persist time by a random amount between 1.5 and 2.5.

//                            float factor = 1.5f + (float)(m_rand.NextDouble());
                            float factor = 2.0f;
                            m_maxPersistTime = (long)((float)m_scene.m_persistAfter * factor);
                            m_minPersistTime = (long)((float)m_scene.m_dontPersistBefore * factor);
                        }
                        else
                        {
                            //If the region is not empty, we want to obey the minimum and maximum persist times
                            //but add a random factor so we stagger the object persistance a little
//                            m_maxPersistTime = (long)((float)m_scene.m_persistAfter * (1.0d - (m_rand.NextDouble() / 5.0d))); //Multiply by 1.0-1.5
//                            m_minPersistTime = (long)((float)m_scene.m_dontPersistBefore * (1.0d + (m_rand.NextDouble() / 2.0d))); //Multiply by 0.8-1.0
                            m_maxPersistTime = m_scene.m_persistAfter;
                            m_minPersistTime = m_scene.m_dontPersistBefore;
                        }
                    }
                }
                m_hasGroupChanged = value;
                
//                m_log.DebugFormat(
//                    "[SCENE OBJECT GROUP]: HasGroupChanged set to {0} for {1} {2}", m_hasGroupChanged, Name, LocalId);
            }

            get { return m_hasGroupChanged; }
        }
        
        /// <summary>
        /// Has the group changed due to an unlink operation?  We record this in order to optimize deletion, since
        /// an unlinked group currently has to be persisted to the database before we can perform an unlink operation.
        /// </summary>
        public bool HasGroupChangedDueToDelink { get; set; }

        private bool isTimeToPersist()
        {
            if (IsSelected || IsDeleted || IsAttachment)
                return false;
            if (!m_hasGroupChanged)
                return false;
            if (m_scene.ShuttingDown)
                return true;

            if (m_minPersistTime == 0 || m_maxPersistTime == 0)
            {
                m_maxPersistTime = m_scene.m_persistAfter;
                m_minPersistTime = m_scene.m_dontPersistBefore;
            }
                
            long currentTime = DateTime.Now.Ticks;

            if (timeLastChanged == 0) timeLastChanged = currentTime;
            if (timeFirstChanged == 0) timeFirstChanged = currentTime;

            if (currentTime - timeLastChanged > m_minPersistTime || currentTime - timeFirstChanged > m_maxPersistTime)
                return true;
            return false;
        }

        /// <summary>
        /// Is this scene object acting as an attachment?
        /// </summary>
        public bool IsAttachment { get; set; }

        /// <summary>
        /// The avatar to which this scene object is attached.
        /// </summary>
        /// <remarks>
        /// If we're not attached to an avatar then this is UUID.Zero
        /// </remarks>
        public UUID AttachedAvatar { get; set; }

        /// <summary>
        /// Attachment point of this scene object to an avatar.
        /// </summary>
        /// <remarks>
        /// 0 if we're not attached to anything
        /// </remarks>
        public uint AttachmentPoint
        {
            get
            {
                return m_rootPart.Shape.State;
            }

            set
            {
                IsAttachment = value != 0;
                m_rootPart.Shape.State = (byte)value;
            }
        }

        /// <summary>
        /// If this scene object has an attachment point then indicate whether there is a point where
        /// attachments are perceivable by avatars other than the avatar to which this object is attached.
        /// </summary>
        /// <remarks>
        /// HUDs are not perceivable by other avatars.
        /// </remarks>
        public bool HasPrivateAttachmentPoint
        {
            get
            {
                return AttachmentPoint >= (uint)OpenMetaverse.AttachmentPoint.HUDCenter2
                    && AttachmentPoint <= (uint)OpenMetaverse.AttachmentPoint.HUDBottomRight;
            }
        }

        public void ClearPartAttachmentData()
        {
            AttachmentPoint = 0;

            // Even though we don't use child part state parameters for attachments any more, we still need to set
            // these to zero since having them non-zero in rezzed scene objects will crash some clients.  Even if
            // we store them correctly, scene objects that we receive from elsewhere might not.
            foreach (SceneObjectPart part in Parts)
                part.Shape.State = 0;
        }

        /// <summary>
        /// Is this scene object phantom?
        /// </summary>
        /// <remarks>
        /// Updating must currently take place through UpdatePrimFlags()
        /// </remarks>
        public bool IsPhantom
        {
            get { return (RootPart.Flags & PrimFlags.Phantom) != 0; }
        }

        /// <summary>
        /// Does this scene object use physics?
        /// </summary>
        /// <remarks>
        /// Updating must currently take place through UpdatePrimFlags()
        /// </remarks>
        public bool UsesPhysics
        {
            get { return (RootPart.Flags & PrimFlags.Physics) != 0; }
        }

        /// <summary>
        /// Is this scene object temporary?
        /// </summary>
        /// <remarks>
        /// Updating must currently take place through UpdatePrimFlags()
        /// </remarks>
        public bool IsTemporary
        {
            get { return (RootPart.Flags & PrimFlags.TemporaryOnRez) != 0; }
        }

        public bool IsVolumeDetect
        {
            get { return RootPart.VolumeDetectActive; }
        }

        private Vector3 lastPhysGroupPos;
        private Quaternion lastPhysGroupRot;

        private bool m_isBackedUp;

        public bool IsBackedUp
        {
            get { return m_isBackedUp; }
        }

        protected MapAndArray<UUID, SceneObjectPart> m_parts = new MapAndArray<UUID, SceneObjectPart>();

        protected ulong m_regionHandle;
        protected SceneObjectPart m_rootPart;
        // private Dictionary<UUID, scriptEvents> m_scriptEvents = new Dictionary<UUID, scriptEvents>();

        private Dictionary<uint, scriptPosTarget> m_targets = new Dictionary<uint, scriptPosTarget>();
        private Dictionary<uint, scriptRotTarget> m_rotTargets = new Dictionary<uint, scriptRotTarget>();

        private bool m_scriptListens_atTarget;
        private bool m_scriptListens_notAtTarget;
        private bool m_scriptListens_atRotTarget;
        private bool m_scriptListens_notAtRotTarget;

        public bool m_dupeInProgress = false;
        internal Dictionary<UUID, string> m_savedScriptState;

        #region Properties

        /// <summary>
        /// The name of an object grouping is always the same as its root part
        /// </summary>
        public override string Name
        {
            get { return RootPart.Name; }
            set { RootPart.Name = value; }
        }

        public string Description
        {
            get { return RootPart.Description; }
            set { RootPart.Description = value; }
        }

        /// <summary>
        /// Added because the Parcel code seems to use it
        /// but not sure a object should have this
        /// as what does it tell us? that some avatar has selected it (but not what Avatar/user)
        /// think really there should be a list (or whatever) in each scenepresence
        /// saying what prim(s) that user has selected.
        /// </summary>
        protected bool m_isSelected = false;

        /// <summary>
        /// Number of prims in this group
        /// </summary>
        public int PrimCount
        {
            get { return m_parts.Count; }
        }

//        protected Quaternion m_rotation = Quaternion.Identity;
//
//        public virtual Quaternion Rotation
//        {
//            get { return m_rotation; }
//            set {
//                m_rotation = value; 
//            }
//        }

        public Quaternion GroupRotation
        {
            get { return m_rootPart.RotationOffset; }
        }

        public Vector3 GroupScale
        {
            get
            {
                Vector3 minScale = new Vector3(Constants.RegionSize, Constants.RegionSize, Constants.RegionSize);
                Vector3 maxScale = Vector3.Zero;
                Vector3 finalScale = new Vector3(0.5f, 0.5f, 0.5f);
    
                SceneObjectPart[] parts = m_parts.GetArray();
                for (int i = 0; i < parts.Length; i++)
                {
                    SceneObjectPart part = parts[i];
                    Vector3 partscale = part.Scale;
                    Vector3 partoffset = part.OffsetPosition;
    
                    minScale.X = (partscale.X + partoffset.X < minScale.X) ? partscale.X + partoffset.X : minScale.X;
                    minScale.Y = (partscale.Y + partoffset.Y < minScale.Y) ? partscale.Y + partoffset.Y : minScale.Y;
                    minScale.Z = (partscale.Z + partoffset.Z < minScale.Z) ? partscale.Z + partoffset.Z : minScale.Z;
    
                    maxScale.X = (partscale.X + partoffset.X > maxScale.X) ? partscale.X + partoffset.X : maxScale.X;
                    maxScale.Y = (partscale.Y + partoffset.Y > maxScale.Y) ? partscale.Y + partoffset.Y : maxScale.Y;
                    maxScale.Z = (partscale.Z + partoffset.Z > maxScale.Z) ? partscale.Z + partoffset.Z : maxScale.Z;
                }
    
                finalScale.X = (minScale.X > maxScale.X) ? minScale.X : maxScale.X;
                finalScale.Y = (minScale.Y > maxScale.Y) ? minScale.Y : maxScale.Y;
                finalScale.Z = (minScale.Z > maxScale.Z) ? minScale.Z : maxScale.Z;
    
                return finalScale;
            }
        }

        public UUID GroupID
        {
            get { return m_rootPart.GroupID; }
            set { m_rootPart.GroupID = value; }
        }

        public SceneObjectPart[] Parts
        {
            get { return m_parts.GetArray(); }
        }

        public bool ContainsPart(UUID partID)
        {
            return m_parts.ContainsKey(partID);
        }

        /// <summary>
        /// Does this group contain the given part?
        /// should be able to remove these methods once we have a entity index in scene
        /// </summary>
        /// <param name="localID"></param>
        /// <returns></returns>
        public bool ContainsPart(uint localID)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                if (parts[i].LocalId == localID)
                    return true;
            }

            return false;
        }

        /// <value>
        /// The root part of this scene object
        /// </value>
        public SceneObjectPart RootPart
        {
            get { return m_rootPart; }
        }

        public ulong RegionHandle
        {
            get { return m_regionHandle; }
            set
            {
                m_regionHandle = value;
                SceneObjectPart[] parts = m_parts.GetArray();
                for (int i = 0; i < parts.Length; i++)
                    parts[i].RegionHandle = value;
            }
        }

        /// <summary>
        /// Check both the attachment property and the relevant properties of the underlying root part.
        /// </summary>
        /// <remarks>
        /// This is necessary in some cases, particularly when a scene object has just crossed into a region and doesn't
        /// have the IsAttachment property yet checked.
        /// 
        /// FIXME: However, this should be fixed so that this property
        /// propertly reflects the underlying status.
        /// </remarks>
        /// <returns></returns>
        public bool IsAttachmentCheckFull()
        {
            return (IsAttachment || (m_rootPart.Shape.PCode == 9 && m_rootPart.Shape.State != 0));
        }



        private struct avtocrossInfo
        {
            public ScenePresence av;
            public uint ParentID;
        }

        /// <summary>
        /// The absolute position of this scene object in the scene
        /// </summary>
        public override Vector3 AbsolutePosition
        {
            get { return m_rootPart.GroupPosition; }
            set
            {
                Vector3 val = value;

                if (Scene != null)
                {
                    if (
                        // (Scene.TestBorderCross(val - Vector3.UnitX, Cardinals.E)
                        //     || Scene.TestBorderCross(val + Vector3.UnitX, Cardinals.W)
                        //     || Scene.TestBorderCross(val - Vector3.UnitY, Cardinals.N)
                        //     || Scene.TestBorderCross(val + Vector3.UnitY, Cardinals.S))
                        // Experimental change for better border crossings.
                        //    The commented out original lines above would, it seems, trigger
                        //    a border crossing a little early or late depending on which
                        //    direction the object was moving.
                        (Scene.TestBorderCross(val, Cardinals.E)
                            || Scene.TestBorderCross(val, Cardinals.W)
                            || Scene.TestBorderCross(val, Cardinals.N)
                            || Scene.TestBorderCross(val, Cardinals.S))
                        && !IsAttachmentCheckFull() && (!Scene.LoadingPrims))
                    {
                        IEntityTransferModule entityTransfer = m_scene.RequestModuleInterface<IEntityTransferModule>();
                        uint x = 0;
                        uint y = 0;
                        string version = String.Empty;
                        Vector3 newpos = Vector3.Zero;
                        OpenSim.Services.Interfaces.GridRegion destination = null;

                        if (m_rootPart.KeyframeMotion != null)
                            m_rootPart.KeyframeMotion.StartCrossingCheck();

                        bool canCross = true;
                        foreach (ScenePresence av in m_linkedAvatars)
                        {
                            // We need to cross these agents. First, let's find
                            // out if any of them can't cross for some reason.
                            // We have to deny the crossing entirely if any
                            // of them are banned. Alternatively, we could
                            // unsit banned agents....


                            // We set the avatar position as being the object
                            // position to get the region to send to
                            if ((destination = entityTransfer.GetDestination(m_scene, av.UUID, val, out x, out y, out version, out newpos)) == null)
                            {
                                canCross = false;
                                break;
                            }

                            m_log.DebugFormat("[SCENE OBJECT]: Avatar {0} needs to be crossed to {1}", av.Name, destination.RegionName);
                        }

                        if (canCross)
                        {
                            // We unparent the SP quietly so that it won't
                            // be made to stand up

                            List<avtocrossInfo> avsToCross = new List<avtocrossInfo>();

                            foreach (ScenePresence av in m_linkedAvatars)
                            {
                                avtocrossInfo avinfo = new avtocrossInfo();
                                SceneObjectPart parentPart = m_scene.GetSceneObjectPart(av.ParentID);
                                if (parentPart != null)
                                    av.ParentUUID = parentPart.UUID;

                                avinfo.av = av;
                                avinfo.ParentID = av.ParentID;
                                avsToCross.Add(avinfo);

                                av.ParentID = 0;
                            }

                            //                            m_linkedAvatars.Clear();
                            m_scene.CrossPrimGroupIntoNewRegion(val, this, true);

                            // Normalize
                            if (val.X >= Constants.RegionSize)
                                val.X -= Constants.RegionSize;
                            if (val.Y >= Constants.RegionSize)
                                val.Y -= Constants.RegionSize;
                            if (val.X < 0)
                                val.X += Constants.RegionSize;
                            if (val.Y < 0)
                                val.Y += Constants.RegionSize;

                            // If it's deleted, crossing was successful
                            if (IsDeleted)
                            {
                                //                                foreach (ScenePresence av in m_linkedAvatars)
                                foreach (avtocrossInfo avinfo in avsToCross)
                                {
                                    ScenePresence av = avinfo.av;
                                    if (!av.IsInTransit) // just in case...
                                    {
                                        m_log.DebugFormat("[SCENE OBJECT]: Crossing avatar {0} to {1}", av.Name, val);

                                        av.IsInTransit = true;

                                        CrossAgentToNewRegionDelegate d = entityTransfer.CrossAgentToNewRegionAsync;
                                        d.BeginInvoke(av, val, destination, av.Flying, version, CrossAgentToNewRegionCompleted, d);
                                    }
                                    else
                                        m_log.DebugFormat("[SCENE OBJECT]: Crossing avatar alreasy in transit {0} to {1}", av.Name, val);
                                }
                                avsToCross.Clear();
                                return;
                            }
                            else // cross failed, put avas back ??
                            {
                                foreach (avtocrossInfo avinfo in avsToCross)
                                {
                                    ScenePresence av = avinfo.av;
                                    av.ParentUUID = UUID.Zero;
                                    av.ParentID = avinfo.ParentID;
//                                    m_linkedAvatars.Add(av);
                                }
                            }
                            avsToCross.Clear();

                        }
                        else
                        {
                            if (m_rootPart.KeyframeMotion != null)
                                m_rootPart.KeyframeMotion.CrossingFailure();

                            if (RootPart.PhysActor != null)
                            {
                                RootPart.PhysActor.CrossingFailure();
                            }
                        }
                        Vector3 oldp = AbsolutePosition;
                        val.X = Util.Clamp<float>(oldp.X, 0.5f, (float)Constants.RegionSize - 0.5f);
                        val.Y = Util.Clamp<float>(oldp.Y, 0.5f, (float)Constants.RegionSize - 0.5f);
                        val.Z = Util.Clamp<float>(oldp.Z, 0.5f, 4096.0f);
                    }
                }

/* don't see the need but worse don't see where is restored to false if things stay in
                foreach (SceneObjectPart part in m_parts.GetArray())
                {
                    part.IgnoreUndoUpdate = true;
                }
 */
                if (RootPart.GetStatusSandbox())
                {
                    if (Util.GetDistanceTo(RootPart.StatusSandboxPos, value) > 10)
                    {
                        RootPart.ScriptSetPhysicsStatus(false);
                        
                        if (Scene != null)
                            Scene.SimChat(Utils.StringToBytes("Hit Sandbox Limit"),
                                  ChatTypeEnum.DebugChannel, 0x7FFFFFFF, RootPart.AbsolutePosition, Name, UUID, false);
                        
                        return;
                    }
                }

                // Restuff the new GroupPosition into each SOP of the linkset.
                //    This has the affect of resetting and tainting the physics actors.
                SceneObjectPart[] parts = m_parts.GetArray();
                bool triggerScriptEvent = m_rootPart.GroupPosition != val;
                if (m_dupeInProgress)
                    triggerScriptEvent = false;
                foreach (SceneObjectPart part in parts)
                {
                    part.GroupPosition = val;
                    if (triggerScriptEvent)
                        part.TriggerScriptChangedEvent(Changed.POSITION);
                }

/*
    This seems not needed and should not be needed:
    sp absolute position depends on sit part absolute position fixed above.
    sp ParentPosition is not used anywhere.
    Since presence is sitting, viewer considers it 'linked' to root prim, so it will move/rotate it
    Sending a extra packet with avatar position is not only bandwidth waste, but may cause jitter in viewers due to UPD nature.
 
                if (!m_dupeInProgress)
                {
                    foreach (ScenePresence av in m_linkedAvatars)
                    {
                        SceneObjectPart p = m_scene.GetSceneObjectPart(av.ParentID);
                        if (p != null && m_parts.TryGetValue(p.UUID, out p))
                        {
                            Vector3 offset = p.GetWorldPosition() - av.ParentPosition;
                            av.AbsolutePosition += offset;
//                            av.ParentPosition = p.GetWorldPosition(); //ParentPosition gets cleared by AbsolutePosition
                            av.SendAvatarDataToAllAgents();
                        }
                    }
                }
*/
                //if (m_rootPart.PhysActor != null)
                //{
                //m_rootPart.PhysActor.Position =
                //new PhysicsVector(m_rootPart.GroupPosition.X, m_rootPart.GroupPosition.Y,
                //m_rootPart.GroupPosition.Z);
                //m_scene.PhysicsScene.AddPhysicsActorTaint(m_rootPart.PhysActor);
                //}
                
                if (Scene != null)
                    Scene.EventManager.TriggerParcelPrimCountTainted();
            }
        }

        public override Vector3 Velocity
        {
            get { return RootPart.Velocity; }
            set { RootPart.Velocity = value; }
        }

        private void CrossAgentToNewRegionCompleted(IAsyncResult iar)
        {
            CrossAgentToNewRegionDelegate icon = (CrossAgentToNewRegionDelegate)iar.AsyncState;
            ScenePresence agent = icon.EndInvoke(iar);

            //// If the cross was successful, this agent is a child agent
            if (agent.IsChildAgent)
            {
                if (agent.ParentUUID != UUID.Zero)
                {
                    agent.ParentPart = null;
//                    agent.ParentPosition = Vector3.Zero;
//                    agent.ParentUUID = UUID.Zero;
                }
            }

            agent.ParentUUID = UUID.Zero;

//                agent.Reset();
//            else // Not successful
//                agent.RestoreInCurrentScene();

            // In any case
            agent.IsInTransit = false;

            m_log.DebugFormat("[SCENE OBJECT]: Crossing agent {0} {1} completed.", agent.Firstname, agent.Lastname);
        }

        public override uint LocalId
        {
            get { return m_rootPart.LocalId; }
            set { m_rootPart.LocalId = value; }
        }

        public override UUID UUID
        {
            get { return m_rootPart.UUID; }
            set 
            {
                lock (m_parts.SyncRoot)
                {
                    m_parts.Remove(m_rootPart.UUID);
                    m_rootPart.UUID = value;
                    m_parts.Add(value, m_rootPart);
                }
            }
        }

        public UUID LastOwnerID
        {
            get { return m_rootPart.LastOwnerID; }
            set { m_rootPart.LastOwnerID = value; }
        }

        public UUID OwnerID
        {
            get { return m_rootPart.OwnerID; }
            set { m_rootPart.OwnerID = value; }
        }

        public float Damage
        {
            get { return m_rootPart.Damage; }
            set { m_rootPart.Damage = value; }
        }

        public Color Color
        {
            get { return m_rootPart.Color; }
            set { m_rootPart.Color = value; }
        }

        public string Text
        {
            get {
                string returnstr = m_rootPart.Text;
                if (returnstr.Length  > 255)
                {
                    returnstr = returnstr.Substring(0, 255);
                }
                return returnstr;
            }
            set { m_rootPart.Text = value; }
        }

        protected virtual bool InSceneBackup
        {
            get { return true; }
        }
        
        public bool IsSelected
        {
            get { return m_isSelected; }
            set
            {
                m_isSelected = value;
                // Tell physics engine that group is selected

                // this is not right
                // but ode engines should only really need to know about root part
                // so they can put entire object simulation on hold and not colliding
                // keep as was for now
                
                PhysicsActor pa = m_rootPart.PhysActor;
                if (pa != null)
                {
                    pa.Selected = value;

                    // Pass it on to the children.
                    SceneObjectPart[] parts = m_parts.GetArray();
                    for (int i = 0; i < parts.Length; i++)
                    {
                        SceneObjectPart child = parts[i];

                        PhysicsActor childPa = child.PhysActor;
                        if (childPa != null)
                            childPa.Selected = value;
                    }
                }
                if (RootPart.KeyframeMotion != null)
                    RootPart.KeyframeMotion.Selected = value;
            }
        }

        public void PartSelectChanged(bool partSelect)
        {
            // any part selected makes group selected
            if (m_isSelected == partSelect)
                return;

            if (partSelect)
            {
                IsSelected = partSelect;
//                if (!IsAttachment)
//                    ScheduleGroupForFullUpdate();
            }
            else
            {
                // bad bad bad 2 heavy for large linksets
                // since viewer does send lot of (un)selects
                // this needs to be replaced by a specific list or count ?
                // but that will require extra code in several places

                SceneObjectPart[] parts = m_parts.GetArray();
                for (int i = 0; i < parts.Length; i++)
                {
                    SceneObjectPart part = parts[i];
                    if (part.IsSelected)
                        return;
                }
                IsSelected = partSelect;
                if (!IsAttachment)
                {
                    ScheduleGroupForFullUpdate();
                }
            }
        }

        private SceneObjectPart m_PlaySoundMasterPrim = null;
        public SceneObjectPart PlaySoundMasterPrim
        {
            get { return m_PlaySoundMasterPrim; }
            set { m_PlaySoundMasterPrim = value; }
        }

        private List<SceneObjectPart> m_PlaySoundSlavePrims = new List<SceneObjectPart>();
        public List<SceneObjectPart> PlaySoundSlavePrims
        {
            get { return m_PlaySoundSlavePrims; }
            set { m_PlaySoundSlavePrims = value; }
        }

        private SceneObjectPart m_LoopSoundMasterPrim = null;
        public SceneObjectPart LoopSoundMasterPrim
        {
            get { return m_LoopSoundMasterPrim; }
            set { m_LoopSoundMasterPrim = value; }
        }

        private List<SceneObjectPart> m_LoopSoundSlavePrims = new List<SceneObjectPart>();
        public List<SceneObjectPart> LoopSoundSlavePrims
        {
            get { return m_LoopSoundSlavePrims; }
            set { m_LoopSoundSlavePrims = value; }
        }

        /// <summary>
        /// The UUID for the region this object is in.
        /// </summary>
        public UUID RegionUUID
        {
            get
            {
                if (m_scene != null)
                {
                    return m_scene.RegionInfo.RegionID;
                }
                return UUID.Zero;
            }
        }

        /// <summary>
        /// The item ID that this object was rezzed from, if applicable.
        /// </summary>
        /// <remarks>
        /// If not applicable will be UUID.Zero
        /// </remarks>
        public UUID FromItemID { get; set; }

        /// <summary>
        /// Refers to the SceneObjectPart.UUID property of the object that this object was rezzed from, if applicable.
        /// </summary>
        /// <remarks>
        /// If not applicable will be UUID.Zero
        /// </remarks>
        public UUID FromPartID { get; set; }

        /// <summary>
        /// The folder ID that this object was rezzed from, if applicable.
        /// </summary>
        /// <remarks>
        /// If not applicable will be UUID.Zero
        /// </remarks>
        public UUID FromFolderID { get; set; }

        /// <summary>
        /// IDs of all avatars sat on this scene object.
        /// </summary>
        /// <remarks>
        /// We need this so that we can maintain a linkset wide ordering of avatars sat on different parts.
        /// This must be locked before it is read or written.
        /// SceneObjectPart sitting avatar add/remove code also locks on this object to avoid race conditions.
        /// No avatar should appear more than once in this list.
        /// Do not manipulate this list directly - use the Add/Remove sitting avatar methods on SceneObjectPart.
        /// </remarks>
        protected internal List<UUID> m_sittingAvatars = new List<UUID>();

        #endregion

//        ~SceneObjectGroup()
//        {
//            //m_log.DebugFormat("[SCENE OBJECT GROUP]: Destructor called for {0}, local id {1}", Name, LocalId);
//            Console.WriteLine("Destructor called for {0}, local id {1}", Name, LocalId);
//        }

        #region Constructors

        /// <summary>
        /// Constructor
        /// </summary>
        public SceneObjectGroup()
        {
            
        }

        /// <summary>
        /// This constructor creates a SceneObjectGroup using a pre-existing SceneObjectPart.
        /// The original SceneObjectPart will be used rather than a copy, preserving
        /// its existing localID and UUID.
        /// </summary>
        /// <param name='part'>Root part for this scene object.</param>
        public SceneObjectGroup(SceneObjectPart part) : this()
        {
            SetRootPart(part);
        }

        /// <summary>
        /// Constructor.  This object is added to the scene later via AttachToScene()
        /// </summary>
        public SceneObjectGroup(UUID ownerID, Vector3 pos, Quaternion rot, PrimitiveBaseShape shape)
        {
            SetRootPart(new SceneObjectPart(ownerID, shape, pos, rot, Vector3.Zero));
        }

        /// <summary>
        /// Constructor.
        /// </summary>
        public SceneObjectGroup(UUID ownerID, Vector3 pos, PrimitiveBaseShape shape)
            : this(ownerID, pos, Quaternion.Identity, shape)
        {
        }

        public void LoadScriptState(XmlDocument doc)
        {
            XmlNodeList nodes = doc.GetElementsByTagName("SavedScriptState");
            if (nodes.Count > 0)
            {
                if (m_savedScriptState == null)
                    m_savedScriptState = new Dictionary<UUID, string>();
                foreach (XmlNode node in nodes)
                {
                    if (node.Attributes["UUID"] != null)
                    {
                        UUID itemid = new UUID(node.Attributes["UUID"].Value);
                        if (itemid != UUID.Zero)
                            m_savedScriptState[itemid] = node.InnerXml;
                    }
                } 
            }
        }

        /// <summary>
        /// Hooks this object up to the backup event so that it is persisted to the database when the update thread executes.
        /// </summary>
        public virtual void AttachToBackup()
        {
            if (IsAttachment) return;
            m_scene.SceneGraph.FireAttachToBackup(this);

            if (InSceneBackup)
            {
                //m_log.DebugFormat(
                //    "[SCENE OBJECT GROUP]: Attaching object {0} {1} to scene presistence sweep", Name, UUID);

                if (!m_isBackedUp)
                    m_scene.EventManager.OnBackup += ProcessBackup;
                
                m_isBackedUp = true;
            }
        }
        
        /// <summary>
        /// Attach this object to a scene.  It will also now appear to agents.
        /// </summary>
        /// <param name="scene"></param>
        public void AttachToScene(Scene scene)
        {
            m_scene = scene;
            RegionHandle = m_scene.RegionInfo.RegionHandle;

            if (m_rootPart.Shape.PCode != 9 || m_rootPart.Shape.State == 0)
                m_rootPart.ParentID = 0;
            if (m_rootPart.LocalId == 0)
                m_rootPart.LocalId = m_scene.AllocateLocalId();

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (Object.ReferenceEquals(part, m_rootPart))
                    continue;

                if (part.LocalId == 0)
                    part.LocalId = m_scene.AllocateLocalId();

                part.ParentID = m_rootPart.LocalId;
                //m_log.DebugFormat("[SCENE]: Given local id {0} to part {1}, linknum {2}, parent {3} {4}", part.LocalId, part.UUID, part.LinkNum, part.ParentID, part.ParentUUID);
            }

            ApplyPhysics();

            if (RootPart.PhysActor != null)
                RootPart.Force = RootPart.Force;
            if (RootPart.PhysActor != null)
                RootPart.Torque = RootPart.Torque;
            if (RootPart.PhysActor != null)
                RootPart.Buoyancy = RootPart.Buoyancy;

            // Don't trigger the update here - otherwise some client issues occur when multiple updates are scheduled
            // for the same object with very different properties.  The caller must schedule the update.
            //ScheduleGroupForFullUpdate();
        }

        public EntityIntersection TestIntersection(Ray hRay, bool frontFacesOnly, bool faceCenters)
        {
            // We got a request from the inner_scene to raytrace along the Ray hRay
            // We're going to check all of the prim in this group for intersection with the ray
            // If we get a result, we're going to find the closest result to the origin of the ray
            // and send back the intersection information back to the innerscene.

            EntityIntersection result = new EntityIntersection();

            SceneObjectPart[] parts = m_parts.GetArray();

            // Find closest hit here
            float idist = float.MaxValue;

            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];

                // Temporary commented to stop compiler warning
                //Vector3 partPosition =
                //    new Vector3(part.AbsolutePosition.X, part.AbsolutePosition.Y, part.AbsolutePosition.Z);
                Quaternion parentrotation = GroupRotation;

                // Telling the prim to raytrace.
                //EntityIntersection inter = part.TestIntersection(hRay, parentrotation);

                EntityIntersection inter = part.TestIntersectionOBB(hRay, parentrotation, frontFacesOnly, faceCenters);

                if (inter.HitTF)
                {
                    // We need to find the closest prim to return to the testcaller along the ray
                    if (inter.distance < idist)
                    {
                        result.HitTF = true;
                        result.ipoint = inter.ipoint;
                        result.obj = part;
                        result.normal = inter.normal;
                        result.distance = inter.distance;

                        idist = inter.distance;
                    }
                }
            }
            return result;
        }

        /// <summary>
        /// Gets a vector representing the size of the bounding box containing all the prims in the group
        /// Treats all prims as rectangular, so no shape (cut etc) is taken into account
        /// offsetHeight is the offset in the Z axis from the centre of the bounding box to the centre of the root prim
        /// </summary>
        /// <returns></returns>
        public void GetAxisAlignedBoundingBoxRaw(out float minX, out float maxX, out float minY, out float maxY, out float minZ, out float maxZ)
        {
            maxX = float.MinValue;
            maxY = float.MinValue;
            maxZ = float.MinValue;
            minX = float.MaxValue;
            minY = float.MaxValue;
            minZ = float.MaxValue;

            SceneObjectPart[] parts = m_parts.GetArray();
            foreach (SceneObjectPart part in parts)
            {
                Vector3 worldPos = part.GetWorldPosition();
                Vector3 offset = worldPos - AbsolutePosition;
                Quaternion worldRot;
                if (part.ParentID == 0)
                {
                    worldRot = part.RotationOffset;
                }
                else
                {
                    worldRot = part.GetWorldRotation();
                }

                Vector3 frontTopLeft;
                Vector3 frontTopRight;
                Vector3 frontBottomLeft;
                Vector3 frontBottomRight;

                Vector3 backTopLeft;
                Vector3 backTopRight;
                Vector3 backBottomLeft;
                Vector3 backBottomRight;

               // Vector3[] corners = new Vector3[8];

                Vector3 orig = Vector3.Zero;

                frontTopLeft.X = orig.X - (part.Scale.X / 2);
                frontTopLeft.Y = orig.Y - (part.Scale.Y / 2);
                frontTopLeft.Z = orig.Z + (part.Scale.Z / 2);

                frontTopRight.X = orig.X - (part.Scale.X / 2);
                frontTopRight.Y = orig.Y + (part.Scale.Y / 2);
                frontTopRight.Z = orig.Z + (part.Scale.Z / 2);

                frontBottomLeft.X = orig.X - (part.Scale.X / 2);
                frontBottomLeft.Y = orig.Y - (part.Scale.Y / 2);
                frontBottomLeft.Z = orig.Z - (part.Scale.Z / 2);

                frontBottomRight.X = orig.X - (part.Scale.X / 2);
                frontBottomRight.Y = orig.Y + (part.Scale.Y / 2);
                frontBottomRight.Z = orig.Z - (part.Scale.Z / 2);

                backTopLeft.X = orig.X + (part.Scale.X / 2);
                backTopLeft.Y = orig.Y - (part.Scale.Y / 2);
                backTopLeft.Z = orig.Z + (part.Scale.Z / 2);

                backTopRight.X = orig.X + (part.Scale.X / 2);
                backTopRight.Y = orig.Y + (part.Scale.Y / 2);
                backTopRight.Z = orig.Z + (part.Scale.Z / 2);

                backBottomLeft.X = orig.X + (part.Scale.X / 2);
                backBottomLeft.Y = orig.Y - (part.Scale.Y / 2);
                backBottomLeft.Z = orig.Z - (part.Scale.Z / 2);

                backBottomRight.X = orig.X + (part.Scale.X / 2);
                backBottomRight.Y = orig.Y + (part.Scale.Y / 2);
                backBottomRight.Z = orig.Z - (part.Scale.Z / 2);

                

                //m_log.InfoFormat("pre corner 1 is {0} {1} {2}", frontTopLeft.X, frontTopLeft.Y, frontTopLeft.Z);
                //m_log.InfoFormat("pre corner 2 is {0} {1} {2}", frontTopRight.X, frontTopRight.Y, frontTopRight.Z);
                //m_log.InfoFormat("pre corner 3 is {0} {1} {2}", frontBottomRight.X, frontBottomRight.Y, frontBottomRight.Z);
                //m_log.InfoFormat("pre corner 4 is {0} {1} {2}", frontBottomLeft.X, frontBottomLeft.Y, frontBottomLeft.Z);
                //m_log.InfoFormat("pre corner 5 is {0} {1} {2}", backTopLeft.X, backTopLeft.Y, backTopLeft.Z);
                //m_log.InfoFormat("pre corner 6 is {0} {1} {2}", backTopRight.X, backTopRight.Y, backTopRight.Z);
                //m_log.InfoFormat("pre corner 7 is {0} {1} {2}", backBottomRight.X, backBottomRight.Y, backBottomRight.Z);
                //m_log.InfoFormat("pre corner 8 is {0} {1} {2}", backBottomLeft.X, backBottomLeft.Y, backBottomLeft.Z);

                //for (int i = 0; i < 8; i++)
                //{
                //    corners[i] = corners[i] * worldRot;
                //    corners[i] += offset;

                //    if (corners[i].X > maxX)
                //        maxX = corners[i].X;
                //    if (corners[i].X < minX)
                //        minX = corners[i].X;

                //    if (corners[i].Y > maxY)
                //        maxY = corners[i].Y;
                //    if (corners[i].Y < minY)
                //        minY = corners[i].Y;

                //    if (corners[i].Z > maxZ)
                //        maxZ = corners[i].Y;
                //    if (corners[i].Z < minZ)
                //        minZ = corners[i].Z;
                //}

                frontTopLeft = frontTopLeft * worldRot;
                frontTopRight = frontTopRight * worldRot;
                frontBottomLeft = frontBottomLeft * worldRot;
                frontBottomRight = frontBottomRight * worldRot;

                backBottomLeft = backBottomLeft * worldRot;
                backBottomRight = backBottomRight * worldRot;
                backTopLeft = backTopLeft * worldRot;
                backTopRight = backTopRight * worldRot;


                frontTopLeft += offset;
                frontTopRight += offset;
                frontBottomLeft += offset;
                frontBottomRight += offset;

                backBottomLeft += offset;
                backBottomRight += offset;
                backTopLeft += offset;
                backTopRight += offset;

                //m_log.InfoFormat("corner 1 is {0} {1} {2}", frontTopLeft.X, frontTopLeft.Y, frontTopLeft.Z);
                //m_log.InfoFormat("corner 2 is {0} {1} {2}", frontTopRight.X, frontTopRight.Y, frontTopRight.Z);
                //m_log.InfoFormat("corner 3 is {0} {1} {2}", frontBottomRight.X, frontBottomRight.Y, frontBottomRight.Z);
                //m_log.InfoFormat("corner 4 is {0} {1} {2}", frontBottomLeft.X, frontBottomLeft.Y, frontBottomLeft.Z);
                //m_log.InfoFormat("corner 5 is {0} {1} {2}", backTopLeft.X, backTopLeft.Y, backTopLeft.Z);
                //m_log.InfoFormat("corner 6 is {0} {1} {2}", backTopRight.X, backTopRight.Y, backTopRight.Z);
                //m_log.InfoFormat("corner 7 is {0} {1} {2}", backBottomRight.X, backBottomRight.Y, backBottomRight.Z);
                //m_log.InfoFormat("corner 8 is {0} {1} {2}", backBottomLeft.X, backBottomLeft.Y, backBottomLeft.Z);

                if (frontTopRight.X > maxX)
                    maxX = frontTopRight.X;
                if (frontTopLeft.X > maxX)
                    maxX = frontTopLeft.X;
                if (frontBottomRight.X > maxX)
                    maxX = frontBottomRight.X;
                if (frontBottomLeft.X > maxX)
                    maxX = frontBottomLeft.X;

                if (backTopRight.X > maxX)
                    maxX = backTopRight.X;
                if (backTopLeft.X > maxX)
                    maxX = backTopLeft.X;
                if (backBottomRight.X > maxX)
                    maxX = backBottomRight.X;
                if (backBottomLeft.X > maxX)
                    maxX = backBottomLeft.X;

                if (frontTopRight.X < minX)
                    minX = frontTopRight.X;
                if (frontTopLeft.X < minX)
                    minX = frontTopLeft.X;
                if (frontBottomRight.X < minX)
                    minX = frontBottomRight.X;
                if (frontBottomLeft.X < minX)
                    minX = frontBottomLeft.X;

                if (backTopRight.X < minX)
                    minX = backTopRight.X;
                if (backTopLeft.X < minX)
                    minX = backTopLeft.X;
                if (backBottomRight.X < minX)
                    minX = backBottomRight.X;
                if (backBottomLeft.X < minX)
                    minX = backBottomLeft.X;

                //
                if (frontTopRight.Y > maxY)
                    maxY = frontTopRight.Y;
                if (frontTopLeft.Y > maxY)
                    maxY = frontTopLeft.Y;
                if (frontBottomRight.Y > maxY)
                    maxY = frontBottomRight.Y;
                if (frontBottomLeft.Y > maxY)
                    maxY = frontBottomLeft.Y;

                if (backTopRight.Y > maxY)
                    maxY = backTopRight.Y;
                if (backTopLeft.Y > maxY)
                    maxY = backTopLeft.Y;
                if (backBottomRight.Y > maxY)
                    maxY = backBottomRight.Y;
                if (backBottomLeft.Y > maxY)
                    maxY = backBottomLeft.Y;

                if (frontTopRight.Y < minY)
                    minY = frontTopRight.Y;
                if (frontTopLeft.Y < minY)
                    minY = frontTopLeft.Y;
                if (frontBottomRight.Y < minY)
                    minY = frontBottomRight.Y;
                if (frontBottomLeft.Y < minY)
                    minY = frontBottomLeft.Y;

                if (backTopRight.Y < minY)
                    minY = backTopRight.Y;
                if (backTopLeft.Y < minY)
                    minY = backTopLeft.Y;
                if (backBottomRight.Y < minY)
                    minY = backBottomRight.Y;
                if (backBottomLeft.Y < minY)
                    minY = backBottomLeft.Y;

                //
                if (frontTopRight.Z > maxZ)
                    maxZ = frontTopRight.Z;
                if (frontTopLeft.Z > maxZ)
                    maxZ = frontTopLeft.Z;
                if (frontBottomRight.Z > maxZ)
                    maxZ = frontBottomRight.Z;
                if (frontBottomLeft.Z > maxZ)
                    maxZ = frontBottomLeft.Z;

                if (backTopRight.Z > maxZ)
                    maxZ = backTopRight.Z;
                if (backTopLeft.Z > maxZ)
                    maxZ = backTopLeft.Z;
                if (backBottomRight.Z > maxZ)
                    maxZ = backBottomRight.Z;
                if (backBottomLeft.Z > maxZ)
                    maxZ = backBottomLeft.Z;

                if (frontTopRight.Z < minZ)
                    minZ = frontTopRight.Z;
                if (frontTopLeft.Z < minZ)
                    minZ = frontTopLeft.Z;
                if (frontBottomRight.Z < minZ)
                    minZ = frontBottomRight.Z;
                if (frontBottomLeft.Z < minZ)
                    minZ = frontBottomLeft.Z;

                if (backTopRight.Z < minZ)
                    minZ = backTopRight.Z;
                if (backTopLeft.Z < minZ)
                    minZ = backTopLeft.Z;
                if (backBottomRight.Z < minZ)
                    minZ = backBottomRight.Z;
                if (backBottomLeft.Z < minZ)
                    minZ = backBottomLeft.Z;
            }
        }

        public Vector3 GetAxisAlignedBoundingBox(out float offsetHeight)
        {
            float minX;
            float maxX;
            float minY;
            float maxY;
            float minZ;
            float maxZ;

            GetAxisAlignedBoundingBoxRaw(out minX, out maxX, out minY, out maxY, out minZ, out maxZ);
            Vector3 boundingBox = new Vector3(maxX - minX, maxY - minY, maxZ - minZ);

            offsetHeight = 0;
            float lower = (minZ * -1);
            if (lower > maxZ)
            {
                offsetHeight = lower - (boundingBox.Z / 2);

            }
            else if (maxZ > lower)
            {
                offsetHeight = maxZ - (boundingBox.Z / 2);
                offsetHeight *= -1;
            }

           // m_log.InfoFormat("BoundingBox is {0} , {1} , {2} ", boundingBox.X, boundingBox.Y, boundingBox.Z);
            return boundingBox;
        }

        #endregion

        public void GetResourcesCosts(SceneObjectPart apart,
            out float linksetResCost, out float linksetPhysCost, out float partCost, out float partPhysCost)
        {
            // this information may need to be cached

            float cost;
            float tmpcost;

            bool ComplexCost = false;

            SceneObjectPart p;
            SceneObjectPart[] parts;

            lock (m_parts)
            {
                parts = m_parts.GetArray();
            }

            int nparts = parts.Length;
          

            for (int i = 0; i < nparts; i++)
            {
                p = parts[i];

                if (p.UsesComplexCost)
                {
                    ComplexCost = true;
                    break;
                }
            }

            if (ComplexCost)
            {
                linksetResCost = 0;
                linksetPhysCost = 0;
                partCost = 0; 
                partPhysCost = 0;

                for (int i = 0; i < nparts; i++)
                {
                    p = parts[i];

                    cost = p.StreamingCost;
                    tmpcost = p.SimulationCost;
                    if (tmpcost > cost)
                        cost = tmpcost;
                    tmpcost = p.PhysicsCost;
                    if (tmpcost > cost)
                        cost = tmpcost;

                    linksetPhysCost += tmpcost;
                    linksetResCost += cost;

                    if (p == apart)
                    {
                        partCost = cost;
                        partPhysCost = tmpcost;
                    }
                }
            }
            else
            {
                partPhysCost = 1.0f;
                partCost = 1.0f;
                linksetResCost = (float)nparts;
                linksetPhysCost = linksetResCost;
            }
        }

        public void GetSelectedCosts(out float PhysCost, out float StreamCost, out float SimulCost)
        {
            SceneObjectPart p;
            SceneObjectPart[] parts;

            lock (m_parts)
            {
                parts = m_parts.GetArray();
            }

            int nparts = parts.Length;

            PhysCost = 0;
            StreamCost = 0;
            SimulCost = 0;

            for (int i = 0; i < nparts; i++)
            {
                p = parts[i];

                StreamCost += p.StreamingCost;
                SimulCost += p.SimulationCost;
                PhysCost += p.PhysicsCost;
            }
        }

        public void SaveScriptedState(XmlTextWriter writer)
        {
            SaveScriptedState(writer, false);
        }

        public void SaveScriptedState(XmlTextWriter writer, bool oldIDs)
        {
            XmlDocument doc = new XmlDocument();
            Dictionary<UUID,string> states = new Dictionary<UUID,string>();

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                Dictionary<UUID, string> pstates = parts[i].Inventory.GetScriptStates(oldIDs);
                foreach (KeyValuePair<UUID, string> kvp in pstates)
                    states[kvp.Key] = kvp.Value;
            }

            if (states.Count > 0)
            {
                // Now generate the necessary XML wrappings
                writer.WriteStartElement(String.Empty, "GroupScriptStates", String.Empty);
                foreach (UUID itemid in states.Keys)
                {
                    doc.LoadXml(states[itemid]);
                    writer.WriteStartElement(String.Empty, "SavedScriptState", String.Empty);
                    writer.WriteAttributeString(String.Empty, "UUID", String.Empty, itemid.ToString());
                    writer.WriteRaw(doc.DocumentElement.OuterXml); // Writes ScriptState element
                    writer.WriteEndElement(); // End of SavedScriptState
                }
                writer.WriteEndElement(); // End of GroupScriptStates
            }
        }

        /// <summary>
        /// Add the avatar to this linkset (avatar is sat).
        /// </summary>
        /// <param name="agentID"></param>
        public void AddAvatar(UUID agentID)
        {
            ScenePresence presence;
            if (m_scene.TryGetScenePresence(agentID, out presence))
            {
                if (!m_linkedAvatars.Contains(presence))
                {
                    m_linkedAvatars.Add(presence);
                }
            }
        }

        /// <summary>
        /// Delete the avatar from this linkset (avatar is unsat).
        /// </summary>
        /// <param name="agentID"></param>
        public void DeleteAvatar(UUID agentID)
        {
            ScenePresence presence;
            if (m_scene.TryGetScenePresence(agentID, out presence))
            {
                if (m_linkedAvatars.Contains(presence))
                {
                    m_linkedAvatars.Remove(presence);
                }
            }
        }

        /// <summary>
        /// Returns the list of linked presences (avatars sat on this group)
        /// </summary>
        /// <param name="agentID"></param>
        public List<ScenePresence> GetLinkedAvatars()
        {
            return m_linkedAvatars;
        }

        /// <summary>
        /// Attach this scene object to the given avatar.
        /// </summary>
        /// <param name="agentID"></param>
        /// <param name="attachmentpoint"></param>
        /// <param name="AttachOffset"></param>
        private void AttachToAgent(
            ScenePresence avatar, SceneObjectGroup so, uint attachmentpoint, Vector3 attachOffset, bool silent)
        {
            if (avatar != null)
            {
                // don't attach attachments to child agents
                if (avatar.IsChildAgent) return;

                // Remove from database and parcel prim count
                m_scene.DeleteFromStorage(so.UUID);
                m_scene.EventManager.TriggerParcelPrimCountTainted();

                so.AttachedAvatar = avatar.UUID;

                if (so.RootPart.PhysActor != null)
                {
                    m_scene.PhysicsScene.RemovePrim(so.RootPart.PhysActor);
                    so.RootPart.PhysActor = null;
                }

                so.AbsolutePosition = attachOffset;
                so.RootPart.AttachedPos = attachOffset;
                so.IsAttachment = true;
                so.RootPart.SetParentLocalId(avatar.LocalId);
                so.AttachmentPoint = attachmentpoint;

                avatar.AddAttachment(this);

                if (!silent)
                {
                    // Killing it here will cause the client to deselect it
                    // It then reappears on the avatar, deselected
                    // through the full update below
                    //
                    if (IsSelected)
                    {
                        m_scene.SendKillObject(new List<uint> { m_rootPart.LocalId });
                    }

                    IsSelected = false; // fudge....
                    ScheduleGroupForFullUpdate();
                }
            }
            else
            {
                m_log.WarnFormat(
                    "[SOG]: Tried to add attachment {0} to avatar with UUID {1} in region {2} but the avatar is not present", 
                    UUID, avatar.ControllingClient.AgentId, Scene.RegionInfo.RegionName);
            }
        }

        public byte GetAttachmentPoint()
        {
            return m_rootPart.Shape.State;
        }

        public void DetachToGround()
        {
            ScenePresence avatar = m_scene.GetScenePresence(AttachedAvatar);
            if (avatar == null)
                return;

            avatar.RemoveAttachment(this);

            Vector3 detachedpos = new Vector3(127f,127f,127f);
            if (avatar == null)
                return;

            detachedpos = avatar.AbsolutePosition;
            FromItemID = UUID.Zero;

            AbsolutePosition = detachedpos;
            AttachedAvatar = UUID.Zero;

            //SceneObjectPart[] parts = m_parts.GetArray();
            //for (int i = 0; i < parts.Length; i++)
            //    parts[i].AttachedAvatar = UUID.Zero;

            m_rootPart.SetParentLocalId(0);
            AttachmentPoint = (byte)0;
            // must check if buildind should be true or false here
            m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive,false);
            HasGroupChanged = true;
            RootPart.Rezzed = DateTime.Now;
            RootPart.RemFlag(PrimFlags.TemporaryOnRez);
            AttachToBackup();
            m_scene.EventManager.TriggerParcelPrimCountTainted();
            m_rootPart.ScheduleFullUpdate();
            m_rootPart.ClearUndoState();
        }

        public void DetachToInventoryPrep()
        {
            ScenePresence avatar = m_scene.GetScenePresence(AttachedAvatar);
            //Vector3 detachedpos = new Vector3(127f, 127f, 127f);
            if (avatar != null)
            {
                //detachedpos = avatar.AbsolutePosition;
                avatar.RemoveAttachment(this);
            }

            AttachedAvatar = UUID.Zero;

            /*SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                parts[i].AttachedAvatar = UUID.Zero;*/

            m_rootPart.SetParentLocalId(0);
            //m_rootPart.SetAttachmentPoint((byte)0);
            IsAttachment = false;
            AbsolutePosition = m_rootPart.AttachedPos;
            //m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_scene.m_physicalPrim);
            //AttachToBackup();
            //m_rootPart.ScheduleFullUpdate();
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="part"></param>
        private void SetPartAsNonRoot(SceneObjectPart part)
        {
            part.ParentID = m_rootPart.LocalId;
            part.ClearUndoState();
        }

        public ushort GetTimeDilation()
        {
            return Utils.FloatToUInt16(m_scene.TimeDilation, 0.0f, 1.0f);
        }
        
        /// <summary>
        /// Set a part to act as the root part for this scene object
        /// </summary>
        /// <param name="part"></param>
        public void SetRootPart(SceneObjectPart part)
        {
            if (part == null)
                throw new ArgumentNullException("Cannot give SceneObjectGroup a null root SceneObjectPart");

            part.SetParent(this);
            m_rootPart = part;
            if (!IsAttachment)
                part.ParentID = 0;
            part.LinkNum = 0;
            
            m_parts.Add(m_rootPart.UUID, m_rootPart);
        }

        /// <summary>
        /// Add a new part to this scene object.  The part must already be correctly configured.
        /// </summary>
        /// <param name="part"></param>
        public void AddPart(SceneObjectPart part)
        {
            part.SetParent(this);
            m_parts.Add(part.UUID, part);

            part.LinkNum = m_parts.Count;

            if (part.LinkNum == 2)
                RootPart.LinkNum = 1;
        }

        /// <summary>
        /// Make sure that every non root part has the proper parent root part local id
        /// </summary>
        private void UpdateParentIDs()
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (part.UUID != m_rootPart.UUID)
                    part.ParentID = m_rootPart.LocalId;
            }
        }

        public void RegenerateFullIDs()
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                parts[i].UUID = UUID.Random();
        }

        // helper provided for parts.
        public int GetSceneMaxUndo()
        {
            if (m_scene != null)
                return m_scene.MaxUndoCount;
            return 5;
        }

        // justincc: I don't believe this hack is needed any longer, especially since the physics
        // parts of set AbsolutePosition were already commented out.  By changing HasGroupChanged to false
        // this method was preventing proper reload of scene objects.
        
        // dahlia: I had to uncomment it, without it meshing was failing on some prims and objects
        // at region startup
        
        // teravus: After this was removed from the linking algorithm, Linked prims no longer collided 
        // properly when non-physical if they havn't been moved.   This breaks ALL builds.
        // see: http://opensimulator.org/mantis/view.php?id=3108
        
        // Here's the deal, this is ABSOLUTELY CRITICAL so the physics scene gets the update about the 
        // position of linkset prims.  IF YOU CHANGE THIS, YOU MUST TEST colliding with just linked and 
        // unmoved prims!  As soon as you move a Prim/group, it will collide properly because Absolute 
        // Position has been set!
        
        public void ResetChildPrimPhysicsPositions()
        {
            // Setting this SOG's absolute position also loops through and sets the positions
            //    of the SOP's in this SOG's linkset. This has the side affect of making sure
            //    the physics world matches the simulated world.
            AbsolutePosition = AbsolutePosition; // could someone in the know please explain how this works?

            // teravus: AbsolutePosition is NOT a normal property!
            // the code in the getter of AbsolutePosition is significantly different then the code in the setter!
            // jhurliman: Then why is it a property instead of two methods?
        }

        public UUID GetPartsFullID(uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                return part.UUID;
            }
            return UUID.Zero;
        }

        public void ObjectGrabHandler(uint localId, Vector3 offsetPos, IClientAPI remoteClient)
        {
            if (m_rootPart.LocalId == localId)
            {
                OnGrabGroup(offsetPos, remoteClient);
            }
            else
            {
                SceneObjectPart part = GetPart(localId);
                OnGrabPart(part, offsetPos, remoteClient);
            }
        }

        public virtual void OnGrabPart(SceneObjectPart part, Vector3 offsetPos, IClientAPI remoteClient)
        {
//            m_log.DebugFormat(
//                "[SCENE OBJECT GROUP]: Processing OnGrabPart for {0} on {1} {2}, offsetPos {3}",
//                remoteClient.Name, part.Name, part.LocalId, offsetPos);

//            part.StoreUndoState();
            part.OnGrab(offsetPos, remoteClient);
        }

        public virtual void OnGrabGroup(Vector3 offsetPos, IClientAPI remoteClient)
        {
            m_scene.EventManager.TriggerGroupGrab(UUID, offsetPos, remoteClient.AgentId);
        }

        /// <summary>
        /// Delete this group from its scene.
        /// </summary>
        /// 
        /// This only handles the in-world consequences of deletion (e.g. any avatars sitting on it are forcibly stood
        /// up and all avatars receive notification of its removal.  Removal of the scene object from database backup
        /// must be handled by the caller.
        /// 
        /// <param name="silent">If true then deletion is not broadcast to clients</param>
        public void DeleteGroupFromScene(bool silent)
        {
            // We need to keep track of this state in case this group is still queued for backup.
            IsDeleted = true;

            DetachFromBackup();

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];

                Scene.ForEachRootScenePresence(delegate(ScenePresence avatar)
                {
                    if (avatar.ParentID == LocalId)
                        avatar.StandUp();

                    if (!silent)
                    {
                        part.ClearUpdateSchedule();
                        if (part == m_rootPart)
                        {
                            if (!IsAttachment
                                || AttachedAvatar == avatar.ControllingClient.AgentId
                                || !HasPrivateAttachmentPoint)
                                avatar.ControllingClient.SendKillObject(m_regionHandle, new List<uint> { part.LocalId });
                        }
                    }
                });
            }

        }

        public void AddScriptLPS(int count)
        {
            m_scene.SceneGraph.AddToScriptLPS(count);
        }

        public void AddActiveScriptCount(int count)
        {
            SceneGraph d = m_scene.SceneGraph;
            d.AddActiveScripts(count);
        }

        public void aggregateScriptEvents()
        {
            PrimFlags objectflagupdate = (PrimFlags)RootPart.GetEffectiveObjectFlags();

            scriptEvents aggregateScriptEvents = 0;

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (part == null)
                    continue;
                if (part != RootPart)
                    part.Flags = objectflagupdate;
                aggregateScriptEvents |= part.AggregateScriptEvents;
            }

            m_scriptListens_atTarget = ((aggregateScriptEvents & scriptEvents.at_target) != 0);
            m_scriptListens_notAtTarget = ((aggregateScriptEvents & scriptEvents.not_at_target) != 0);

            if (!m_scriptListens_atTarget && !m_scriptListens_notAtTarget)
            {
                lock (m_targets)
                    m_targets.Clear();
                m_scene.RemoveGroupTarget(this);
            }
            m_scriptListens_atRotTarget = ((aggregateScriptEvents & scriptEvents.at_rot_target) != 0);
            m_scriptListens_notAtRotTarget = ((aggregateScriptEvents & scriptEvents.not_at_rot_target) != 0);

            if (!m_scriptListens_atRotTarget && !m_scriptListens_notAtRotTarget)
            {
                lock (m_rotTargets)
                    m_rotTargets.Clear();
                m_scene.RemoveGroupTarget(this);
            }

            ScheduleGroupForFullUpdate();
        }

        public void SetText(string text, Vector3 color, double alpha)
        {
            Color = Color.FromArgb(0xff - (int) (alpha * 0xff),
                                   (int) (color.X * 0xff),
                                   (int) (color.Y * 0xff),
                                   (int) (color.Z * 0xff));
            Text = text;

            HasGroupChanged = true;
            m_rootPart.ScheduleFullUpdate();
        }

        /// <summary>
        /// Apply physics to this group
        /// </summary>
        public void ApplyPhysics()
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            if (parts.Length > 1)
            {
                ResetChildPrimPhysicsPositions();

                // Apply physics to the root prim
                m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, true);


                for (int i = 0; i < parts.Length; i++)
                {
                    SceneObjectPart part = parts[i];
                    if (part.LocalId != m_rootPart.LocalId)
                        part.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), part.VolumeDetectActive, true);
                }
                // Hack to get the physics scene geometries in the right spot
//                ResetChildPrimPhysicsPositions();
                if (m_rootPart.PhysActor != null)
                {
                    m_rootPart.PhysActor.Building = false;
                }
			}
			else
			{
                // Apply physics to the root prim
                m_rootPart.ApplyPhysics(m_rootPart.GetEffectiveObjectFlags(), m_rootPart.VolumeDetectActive, false);
            }
        }

        public void SetOwnerId(UUID userId)
        {
                ForEachPart(delegate(SceneObjectPart part) 
                {
                    
                    part.OwnerID = userId;
                    
                });
        }

        public void ForEachPart(Action<SceneObjectPart> whatToDo)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                whatToDo(parts[i]);
        }

        #region Events

        /// <summary>
        /// Processes backup.
        /// </summary>
        /// <param name="datastore"></param>
        public virtual void ProcessBackup(ISimulationDataService datastore, bool forcedBackup)
        {
            if (!m_isBackedUp)
            {
//                m_log.DebugFormat(
//                    "[WATER WARS]: Ignoring backup of {0} {1} since object is not marked to be backed up", Name, UUID);
                return;
            }

            if (IsDeleted || UUID == UUID.Zero)
            {
//                m_log.DebugFormat(
//                    "[WATER WARS]: Ignoring backup of {0} {1} since object is marked as already deleted", Name, UUID);
                return;
            }

            if ((RootPart.Flags & PrimFlags.TemporaryOnRez) != 0)
                return;

            // Since this is the top of the section of call stack for backing up a particular scene object, don't let
            // any exception propogate upwards.
            try
            {
                if (!m_scene.ShuttingDown || // if shutting down then there will be nothing to handle the return so leave till next restart
                        !m_scene.LoginsEnabled || // We're starting up or doing maintenance, don't mess with things
                        m_scene.LoadingPrims) // Land may not be valid yet
                
                {
                    ILandObject parcel = m_scene.LandChannel.GetLandObject(
                            m_rootPart.GroupPosition.X, m_rootPart.GroupPosition.Y);

                    if (parcel != null && parcel.LandData != null &&
                            parcel.LandData.OtherCleanTime != 0)
                    {
                        if (parcel.LandData.OwnerID != OwnerID &&
                                (parcel.LandData.GroupID != GroupID ||
                                parcel.LandData.GroupID == UUID.Zero))
                        {
                            if ((DateTime.UtcNow - RootPart.Rezzed).TotalMinutes >
                                    parcel.LandData.OtherCleanTime)
                            {
                                DetachFromBackup();
                                m_log.DebugFormat(
                                    "[SCENE OBJECT GROUP]: Returning object {0} due to parcel autoreturn", 
                                     RootPart.UUID);
                                m_scene.AddReturn(OwnerID == GroupID ? LastOwnerID : OwnerID, Name, AbsolutePosition, "parcel autoreturn");
                                m_scene.DeRezObjects(null, new List<uint>() { RootPart.LocalId }, UUID.Zero,
                                        DeRezAction.Return, UUID.Zero);

                                return;
                            }
                        }
                    }

                }

                if (m_scene.UseBackup && HasGroupChanged)
                {
                    // don't backup while it's selected or you're asking for changes mid stream.
                    if (isTimeToPersist() || forcedBackup)
                    {
                        if (m_rootPart.PhysActor != null &&
                            (!m_rootPart.PhysActor.IsPhysical))
                        {
                            // Possible ghost prim
                            if (m_rootPart.PhysActor.Position != m_rootPart.GroupPosition)
                            {
                                foreach (SceneObjectPart part in m_parts.GetArray())
                                {
                                    // Re-set physics actor positions and
                                    // orientations
                                    part.GroupPosition = m_rootPart.GroupPosition;
                                }
                            }
                        }
//                        m_log.DebugFormat(
//                            "[SCENE]: Storing {0}, {1} in {2}",
//                            Name, UUID, m_scene.RegionInfo.RegionName);

                        if (RootPart.Shape.PCode == 9 && RootPart.Shape.State != 0)
                        {
                            RootPart.Shape.State = 0;
                            ScheduleGroupForFullUpdate();
                        }

                        SceneObjectGroup backup_group = Copy(false);
                        backup_group.RootPart.Velocity = RootPart.Velocity;
                        backup_group.RootPart.Acceleration = RootPart.Acceleration;
                        backup_group.RootPart.AngularVelocity = RootPart.AngularVelocity;
                        backup_group.RootPart.ParticleSystem = RootPart.ParticleSystem;
                        HasGroupChanged = false;
                        HasGroupChangedDueToDelink = false;

                        m_scene.EventManager.TriggerOnSceneObjectPreSave(backup_group, this);
/*
                        backup_group.ForEachPart(delegate(SceneObjectPart part) 
                        { 
                            if (part.KeyframeMotion != null)
                            {
                                part.KeyframeMotion = KeyframeMotion.FromData(backup_group, part.KeyframeMotion.Serialize());
//                                part.KeyframeMotion.UpdateSceneObject(this);
                            }
                        });
*/
                        datastore.StoreObject(backup_group, m_scene.RegionInfo.RegionID);

                        backup_group.ForEachPart(delegate(SceneObjectPart part) 
                        { 
                            part.Inventory.ProcessInventoryBackup(datastore); 
                        });

                        backup_group = null;
                    }
//                    else
//                    {
//                        m_log.DebugFormat(
//                            "[SCENE]: Did not update persistence of object {0} {1}, selected = {2}",
//                            Name, UUID, IsSelected);
//                    }
                }
            }
            catch (Exception e)
            {
                m_log.ErrorFormat(
                    "[SCENE]: Storing of {0}, {1} in {2} failed with exception {3}{4}", 
                    Name, UUID, m_scene.RegionInfo.RegionName, e.Message, e.StackTrace);
            }
        }

        #endregion

        /// <summary>
        /// Send the parts of this SOG to a single client
        /// </summary>
        /// <remarks>
        /// Used when the client initially connects and when client sends RequestPrim packet
        /// </remarks>
        /// <param name="remoteClient"></param>
        public void SendFullUpdateToClient(IClientAPI remoteClient)
        {
            RootPart.SendFullUpdate(remoteClient);

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (part != RootPart)
                    part.SendFullUpdate(remoteClient);
            }
        }

        #region Copying

        /// <summary>
        /// Duplicates this object, including operations such as physics set up and attaching to the backup event.
        /// </summary>
        /// <param name="userExposed">True if the duplicate will immediately be in the scene, false otherwise</param>
        /// <returns></returns>
        public SceneObjectGroup Copy(bool userExposed)
        {
            m_dupeInProgress = true;
            SceneObjectGroup dupe = (SceneObjectGroup)MemberwiseClone();
            dupe.m_isBackedUp = false;
            dupe.m_parts = new MapAndArray<OpenMetaverse.UUID, SceneObjectPart>();

            // new group as no sitting avatars            
            dupe.m_linkedAvatars = new List<ScenePresence>();

            // Warning, The following code related to previousAttachmentStatus is needed so that clones of 
            // attachments do not bordercross while they're being duplicated.  This is hacktastic!
            // Normally, setting AbsolutePosition will bordercross a prim if it's outside the region!
            // unless IsAttachment is true!, so to prevent border crossing, we save it's attachment state 
            // (which should be false anyway) set it as an Attachment and then set it's Absolute Position, 
            // then restore it's attachment state

            // This is only necessary when userExposed is false!

            bool previousAttachmentStatus = dupe.IsAttachment;

            if (!userExposed)
                dupe.IsAttachment = true;

            dupe.AbsolutePosition = new Vector3(AbsolutePosition.X, AbsolutePosition.Y, AbsolutePosition.Z);

            if (!userExposed)
            {
                dupe.IsAttachment = previousAttachmentStatus;
            }

            dupe.CopyRootPart(m_rootPart, OwnerID, GroupID, userExposed);
            dupe.m_rootPart.LinkNum = m_rootPart.LinkNum;
            

            if (userExposed)
                dupe.m_rootPart.TrimPermissions();

            List<SceneObjectPart> partList = new List<SceneObjectPart>(m_parts.GetArray());

            partList.Sort(delegate(SceneObjectPart p1, SceneObjectPart p2)
            {
                return p1.LinkNum.CompareTo(p2.LinkNum);
            }
            );

            foreach (SceneObjectPart part in partList)
            {
                SceneObjectPart newPart;
                if (part.UUID != m_rootPart.UUID)
                {
                    newPart = dupe.CopyPart(part, OwnerID, GroupID, userExposed);
                    newPart.LinkNum = part.LinkNum;
                    if (userExposed)
                        newPart.ParentID = dupe.m_rootPart.LocalId;
                 }
                else
                {
                    newPart = dupe.m_rootPart;
                }
/*
                bool isphys = ((newPart.Flags & PrimFlags.Physics) != 0);
                bool isphan = ((newPart.Flags & PrimFlags.Phantom) != 0);

                // Need to duplicate the physics actor as well
                if (userExposed && (isphys || !isphan || newPart.VolumeDetectActive))
                {
                    PrimitiveBaseShape pbs = newPart.Shape;
                    newPart.PhysActor
                        = m_scene.PhysicsScene.AddPrimShape(
                            string.Format("{0}/{1}", newPart.Name, newPart.UUID),
                            pbs,
                            newPart.AbsolutePosition,
                            newPart.Scale,
                            newPart.GetWorldRotation(),
                            isphys,
                            isphan,
                            newPart.LocalId);

                    newPart.DoPhysicsPropertyUpdate(isphys, true);
 */
                if (userExposed)
                    newPart.ApplyPhysics((uint)newPart.Flags,newPart.VolumeDetectActive,true);
//                }
                // copy keyframemotion
                if (part.KeyframeMotion != null)
                    newPart.KeyframeMotion = part.KeyframeMotion.Copy(dupe);
            }

            if (userExposed)
            {
// done above                dupe.UpdateParentIDs();

                if (dupe.m_rootPart.PhysActor != null)
                    dupe.m_rootPart.PhysActor.Building = false; // tell physics to finish building

                dupe.HasGroupChanged = true;
                dupe.AttachToBackup();

                ScheduleGroupForFullUpdate();
            }

            m_dupeInProgress = false;
            return dupe;
        }

        /// <summary>
        /// Copy the given part as the root part of this scene object.
        /// </summary>
        /// <param name="part"></param>
        /// <param name="cAgentID"></param>
        /// <param name="cGroupID"></param>
        public void CopyRootPart(SceneObjectPart part, UUID cAgentID, UUID cGroupID, bool userExposed)
        {
            //            SetRootPart(part.Copy(m_scene.AllocateLocalId(), OwnerID, GroupID, 0, userExposed));
            // give newpart a new local ID lettng old part keep same
            SceneObjectPart newpart = part.Copy(part.LocalId, OwnerID, GroupID, 0, userExposed);
            newpart.LocalId = m_scene.AllocateLocalId();

            SetRootPart(newpart);
            if (userExposed)
                RootPart.Velocity = Vector3.Zero; // In case source is moving
        }

        public void ScriptSetPhysicsStatus(bool usePhysics)
        {
            if (usePhysics)
            {
                if (RootPart.KeyframeMotion != null)
                    RootPart.KeyframeMotion.Stop();
                RootPart.KeyframeMotion = null;
            }
            UpdatePrimFlags(RootPart.LocalId, usePhysics, IsTemporary, IsPhantom, IsVolumeDetect);
        }

        public void ScriptSetTemporaryStatus(bool makeTemporary)
        {
            UpdatePrimFlags(RootPart.LocalId, UsesPhysics, makeTemporary, IsPhantom, IsVolumeDetect);
        }

        public void ScriptSetPhantomStatus(bool makePhantom)
        {
            UpdatePrimFlags(RootPart.LocalId, UsesPhysics, IsTemporary, makePhantom, IsVolumeDetect);
        }

        public void ScriptSetVolumeDetect(bool makeVolumeDetect)
        {
            UpdatePrimFlags(RootPart.LocalId, UsesPhysics, IsTemporary, IsPhantom, makeVolumeDetect);

            /*
            ScriptSetPhantomStatus(false);  // What ever it was before, now it's not phantom anymore

            if (PhysActor != null) // Should always be the case now
            {
                PhysActor.SetVolumeDetect(param);
            }
            if (param != 0)
                AddFlag(PrimFlags.Phantom);

            ScheduleFullUpdate();
            */
        }

        public void applyImpulse(Vector3 impulse)
        {
            if (IsAttachment)
            {
                ScenePresence avatar = m_scene.GetScenePresence(AttachedAvatar);
                if (avatar != null)
                {
                    avatar.PushForce(impulse);
                }
            }
            else
            {
                PhysicsActor pa = RootPart.PhysActor;

                if (pa != null)
                {
                    // false to be applied as a impulse 
                    pa.AddForce(impulse, false);
                    m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
                }
            }
        }

        public void ApplyAngularImpulse(Vector3 impulse)
        {
            PhysicsActor pa = RootPart.PhysActor;

            if (pa != null)
            {
                if (!IsAttachment)
                {
                    // false to be applied as a impulse
                    pa.AddAngularForce(impulse, false);
                    m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
                }
            }
        }

        public Vector3 GetTorque()
        {
            return RootPart.Torque;
        }

         // This is used by both Double-Click Auto-Pilot and llMoveToTarget() in an attached object
        public void moveToTarget(Vector3 target, float tau)
        {
            if (IsAttachment)
            {
                ScenePresence avatar = m_scene.GetScenePresence(AttachedAvatar);
                if (avatar != null)
                {
                    avatar.MoveToTarget(target, false, false);
                }
            }
            else
            {
                PhysicsActor pa = RootPart.PhysActor;

                if (pa != null)
                {
                    pa.PIDTarget = target;
                    pa.PIDTau = tau;
                    pa.PIDActive = true;
                }
            }
        }

        public void stopMoveToTarget()
        {
            PhysicsActor pa = RootPart.PhysActor;

            if (pa != null)
                pa.PIDActive = false;
        }
        
        public void rotLookAt(Quaternion target, float strength, float damping)
        {
            SceneObjectPart rootpart = m_rootPart;
            if (rootpart != null)
            {
                if (IsAttachment)
                {
                /*
                    ScenePresence avatar = m_scene.GetScenePresence(rootpart.AttachedAvatar);
                    if (avatar != null)
                    {
                    Rotate the Av?
                    } */
                }
                else
                {
                    if (rootpart.PhysActor != null)
                    {									// APID must be implemented in your physics system for this to function.
                        rootpart.PhysActor.APIDTarget = new Quaternion(target.X, target.Y, target.Z, target.W);
                        rootpart.PhysActor.APIDStrength = strength;
                        rootpart.PhysActor.APIDDamping = damping;
                        rootpart.PhysActor.APIDActive = true;
                    }
                }
            }
        }

        public void stopLookAt()
        {
            SceneObjectPart rootpart = m_rootPart;
            if (rootpart != null)
            {
                if (rootpart.PhysActor != null)
                {							// APID must be implemented in your physics system for this to function.
                    rootpart.PhysActor.APIDActive = false;
                }
            }
        
        }

        /// <summary>
        /// Uses a PID to attempt to clamp the object on the Z axis at the given height over tau seconds.
        /// </summary>
        /// <param name="height">Height to hover.  Height of zero disables hover.</param>
        /// <param name="hoverType">Determines what the height is relative to </param>
        /// <param name="tau">Number of seconds over which to reach target</param>
        public void SetHoverHeight(float height, PIDHoverType hoverType, float tau)
        {
            PhysicsActor pa = RootPart.PhysActor;

            if (pa != null)
            {
                if (height != 0f)
                {
                    pa.PIDHoverHeight = height;
                    pa.PIDHoverType = hoverType;
                    pa.PIDHoverTau = tau;
                    pa.PIDHoverActive = true;
                }
                else
                {
                    pa.PIDHoverActive = false;
                }
            }
        }

        /// <summary>
        /// Set the owner of the root part.
        /// </summary>
        /// <param name="part"></param>
        /// <param name="cAgentID"></param>
        /// <param name="cGroupID"></param>
        public void SetRootPartOwner(SceneObjectPart part, UUID cAgentID, UUID cGroupID)
        {
            part.LastOwnerID = part.OwnerID;
            part.OwnerID = cAgentID;
            part.GroupID = cGroupID;

            if (part.OwnerID != cAgentID)
            {
                // Apply Next Owner Permissions if we're not bypassing permissions
                if (!m_scene.Permissions.BypassPermissions())
                    ApplyNextOwnerPermissions();
            }

            part.ScheduleFullUpdate();
        }

        /// <summary>
        /// Make a copy of the given part.
        /// </summary>
        /// <param name="part"></param>
        /// <param name="cAgentID"></param>
        /// <param name="cGroupID"></param>
        public SceneObjectPart CopyPart(SceneObjectPart part, UUID cAgentID, UUID cGroupID, bool userExposed)
        {
            // give new ID to the new part, letting old keep original
            //            SceneObjectPart newPart = part.Copy(m_scene.AllocateLocalId(), OwnerID, GroupID, m_parts.Count, userExposed);
            SceneObjectPart newPart = part.Copy(part.LocalId, OwnerID, GroupID, m_parts.Count, userExposed);
            newPart.LocalId = m_scene.AllocateLocalId();
            newPart.SetParent(this);

            AddPart(newPart);

            SetPartAsNonRoot(newPart);
            return newPart;
        }

        /// <summary>
        /// Reset the UUIDs for all the prims that make up this group.
        /// </summary>
        /// <remarks>
        /// This is called by methods which want to add a new group to an existing scene, in order
        /// to ensure that there are no clashes with groups already present.
        /// </remarks>
        public void ResetIDs()
        {
            lock (m_parts.SyncRoot)
            {
                List<SceneObjectPart> partsList = new List<SceneObjectPart>(m_parts.GetArray());
                m_parts.Clear();
                foreach (SceneObjectPart part in partsList)
                {
                    part.ResetIDs(part.LinkNum); // Don't change link nums
                    m_parts.Add(part.UUID, part);
                }
            }
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="part"></param>
        public void ServiceObjectPropertiesFamilyRequest(IClientAPI remoteClient, UUID AgentID, uint RequestFlags)
        {
            remoteClient.SendObjectPropertiesFamilyData(RootPart, RequestFlags);
            
//             remoteClient.SendObjectPropertiesFamilyData(RequestFlags, RootPart.UUID, RootPart.OwnerID, RootPart.GroupID, RootPart.BaseMask,
//                                                         RootPart.OwnerMask, RootPart.GroupMask, RootPart.EveryoneMask, RootPart.NextOwnerMask,
//                                                         RootPart.OwnershipCost, RootPart.ObjectSaleType, RootPart.SalePrice, RootPart.Category,
//                                                         RootPart.CreatorID, RootPart.Name, RootPart.Description);
        }

        public void SetPartOwner(SceneObjectPart part, UUID cAgentID, UUID cGroupID)
        {
            part.OwnerID = cAgentID;
            part.GroupID = cGroupID;
        }

        #endregion

        public override void Update()
        {
            // Check that the group was not deleted before the scheduled update
            // FIXME: This is merely a temporary measure to reduce the incidence of failure when
            // an object has been deleted from a scene before update was processed.
            // A more fundamental overhaul of the update mechanism is required to eliminate all
            // the race conditions.
            if (IsDeleted)
                return;

            // Even temporary objects take part in physics (e.g. temp-on-rez bullets)
            //if ((RootPart.Flags & PrimFlags.TemporaryOnRez) != 0)
            //    return;

            // If we somehow got here to updating the SOG and its root part is not scheduled for update,
            // check to see if the physical position or rotation warrant an update. 
            if (m_rootPart.UpdateFlag == UpdateRequired.NONE)
            {
                bool UsePhysics = ((RootPart.Flags & PrimFlags.Physics) != 0);

                if (UsePhysics && !AbsolutePosition.ApproxEquals(lastPhysGroupPos, 0.02f))
                {
                    m_rootPart.UpdateFlag = UpdateRequired.TERSE;
                    lastPhysGroupPos = AbsolutePosition;
                }

                if (UsePhysics && !GroupRotation.ApproxEquals(lastPhysGroupRot, 0.1f))
                {
                    m_rootPart.UpdateFlag = UpdateRequired.TERSE;
                    lastPhysGroupRot = GroupRotation;
                }
            }

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (!IsSelected)
                    part.UpdateLookAt();
                part.SendScheduledUpdates();
            }
        }

        /// <summary>
        /// Schedule a full update for this scene object to all interested viewers.
        /// </summary>
        /// <remarks>
        /// Ultimately, this should be managed such that region modules can invoke it at the end of a set of operations
        /// so that either all changes are sent at once.  However, currently, a large amount of internal
        /// code will set this anyway when some object properties are changed.
        /// </remarks>
        public void ScheduleGroupForFullUpdate()
        {
//            if (IsAttachment)
//                m_log.DebugFormat("[SOG]: Scheduling full update for {0} {1}", Name, LocalId);
            
            checkAtTargets();
            RootPart.ScheduleFullUpdate();

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (part != RootPart)
                    part.ScheduleFullUpdate();
            }
        }

        /// <summary>
        /// Schedule a terse update for this scene object to all interested viewers.
        /// </summary>
        /// <remarks>
        /// Ultimately, this should be managed such that region modules can invoke it at the end of a set of operations
        /// so that either all changes are sent at once.  However, currently, a large amount of internal
        /// code will set this anyway when some object properties are changed.
        /// </remarks>
        public void ScheduleGroupForTerseUpdate()
        {
//            m_log.DebugFormat("[SOG]: Scheduling terse update for {0} {1}", Name, UUID);

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                parts[i].ScheduleTerseUpdate();
        }

        /// <summary>
        /// Immediately send a full update for this scene object.
        /// </summary>
        public void SendGroupFullUpdate()
        {                       
            if (IsDeleted)
                return;

//            m_log.DebugFormat("[SOG]: Sending immediate full group update for {0} {1}", Name, UUID);            
            
            RootPart.SendFullUpdateToAllClients();

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                if (part != RootPart)
                    part.SendFullUpdateToAllClients();
            }
        }

        /// <summary>
        /// Immediately send an update for this scene object's root prim only.
        /// This is for updates regarding the object as a whole, and none of its parts in particular.
        /// Note: this may not be used by opensim (it probably should) but it's used by
        /// external modules.
        /// </summary>
        public void SendGroupRootTerseUpdate()
        {
            if (IsDeleted)
                return;

            RootPart.SendTerseUpdateToAllClients();
        }

        public void QueueForUpdateCheck()
        {
            if (m_scene == null) // Need to check here as it's null during object creation
                return;
            
            m_scene.SceneGraph.AddToUpdateList(this);
        }

        /// <summary>
        /// Immediately send a terse update for this scene object.
        /// </summary>
        public void SendGroupTerseUpdate()
        {
            if (IsDeleted)
                return;

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                parts[i].SendTerseUpdateToAllClients();
        }

        /// <summary>
        /// Send metadata about the root prim (name, description, sale price, permissions, etc.) to a client.
        /// </summary>
        /// <param name="client"></param>
        public void SendPropertiesToClient(IClientAPI client)
        {
            m_rootPart.SendPropertiesToClient(client);
        }

        #region SceneGroupPart Methods

        /// <summary>
        /// Get the child part by LinkNum
        /// </summary>
        /// <param name="linknum"></param>
        /// <returns>null if no child part with that linknum or child part</returns>
        public SceneObjectPart GetLinkNumPart(int linknum)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                if (parts[i].LinkNum == linknum)
                    return parts[i];
            }

            return null;
        }

        /// <summary>
        /// Get a part with a given UUID
        /// </summary>
        /// <param name="primID"></param>
        /// <returns>null if a part with the primID was not found</returns>
        public SceneObjectPart GetPart(UUID primID)
        {
            SceneObjectPart childPart;
            m_parts.TryGetValue(primID, out childPart);
            return childPart;
        }

        /// <summary>
        /// Get a part with a given local ID
        /// </summary>
        /// <param name="localID"></param>
        /// <returns>null if a part with the local ID was not found</returns>
        public SceneObjectPart GetPart(uint localID)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                if (parts[i].LocalId == localID)
                    return parts[i];
            }

            return null;
        }

        #endregion

        #region Packet Handlers

        /// <summary>
        /// Link the prims in a given group to this group
        /// </summary>
        /// <remarks>
        /// Do not call this method directly - use Scene.LinkObjects() instead to avoid races between threads.
        /// FIXME: There are places where scripts call these methods directly without locking.  This is a potential race condition.
        /// </remarks>
        /// <param name="objectGroup">The group of prims which should be linked to this group</param>
        public void LinkToGroup(SceneObjectGroup objectGroup)
        {
            LinkToGroup(objectGroup, false);
        }

        // Link an existing group to this group.
        // The group being linked need not be a linkset -- it can have just one prim.
        public void LinkToGroup(SceneObjectGroup objectGroup, bool insert)
        {
//            m_log.DebugFormat(
//                "[SCENE OBJECT GROUP]: Linking group with root part {0}, {1} to group with root part {2}, {3}",
//                objectGroup.RootPart.Name, objectGroup.RootPart.UUID, RootPart.Name, RootPart.UUID);

            // Linking to ourselves is not a valid operation.
            if (objectGroup == this)
                return;

            // If the configured linkset capacity is greater than zero,
            // and the new linkset would have a prim count higher than this
            // value, do not link it.
            if (m_scene.m_linksetCapacity > 0 &&
                    (PrimCount + objectGroup.PrimCount) >
                    m_scene.m_linksetCapacity)
            {
                m_log.DebugFormat(
                    "[SCENE OBJECT GROUP]: Cannot link group with root" +
                    " part {0}, {1} ({2} prims) to group with root part" +
                    " {3}, {4} ({5} prims) because the new linkset" +
                    " would exceed the configured maximum of {6}",
                    objectGroup.RootPart.Name, objectGroup.RootPart.UUID,
                    objectGroup.PrimCount, RootPart.Name, RootPart.UUID,
                    PrimCount, m_scene.m_linksetCapacity);

                return;
            }

            // 'linkPart' == the root of the group being linked into this group
            SceneObjectPart linkPart = objectGroup.m_rootPart;

            if (m_rootPart.PhysActor != null)
                m_rootPart.PhysActor.Building = true;
            if (linkPart.PhysActor != null)
                linkPart.PhysActor.Building = true;

            // physics flags from group to be applied to linked parts
            bool grpusephys = UsesPhysics;
            bool grptemporary = IsTemporary;

            // Remember where the group being linked thought it was
            Vector3 oldGroupPosition = linkPart.GroupPosition;
            Quaternion oldRootRotation = linkPart.RotationOffset;

            // A linked SOP remembers its location and rotation relative to the root of a group. 
            // Convert the root of the group being linked to be relative to the
            //   root of the group being linked to.
            // Note: Some of the assignments have complex side effects.

            // First move the new group's root SOP's position to be relative to ours
            // (radams1: Not sure if the multiple setting of OffsetPosition is required. If not,
            //   this code can be reordered to have a more logical flow.)
            linkPart.OffsetPosition = linkPart.GroupPosition - AbsolutePosition;
            // Assign the new parent to the root of the old group
            linkPart.ParentID = m_rootPart.LocalId;
            // Now that it's a child, it's group position is our root position
            linkPart.GroupPosition = AbsolutePosition;

            Vector3 axPos = linkPart.OffsetPosition;
            // Rotate the linking root SOP's position to be relative to the new root prim
            Quaternion parentRot = m_rootPart.RotationOffset;
            axPos *= Quaternion.Conjugate(parentRot);
            linkPart.OffsetPosition = axPos;

            // Make the linking root SOP's rotation relative to the new root prim
            Quaternion oldRot = linkPart.RotationOffset;
            Quaternion newRot = Quaternion.Conjugate(parentRot) * oldRot;
            linkPart.RotationOffset = newRot;

            // If there is only one SOP in a SOG, the LinkNum is zero. I.e., not a linkset.
            // Now that we know this SOG has at least two SOPs in it, the new root
            //    SOP becomes the first in the linkset.
            if (m_rootPart.LinkNum == 0)
                m_rootPart.LinkNum = 1;

            lock (m_parts.SyncRoot)
            {
                // Calculate the new link number for the old root SOP
                int linkNum;
                if (insert)
                {
                    linkNum = 2;
                    foreach (SceneObjectPart part in Parts)
                    {
                        if (part.LinkNum > 1)
                            part.LinkNum++;
                    }
                }
                else
                {
                    linkNum = PrimCount + 1;
                }

                // Add the old root SOP as a part in our group's list
                m_parts.Add(linkPart.UUID, linkPart);

                linkPart.SetParent(this);
                linkPart.CreateSelected = true;

                // let physics know preserve part volume dtc messy since UpdatePrimFlags doesn't look to parent changes for now
                linkPart.UpdatePrimFlags(grpusephys, grptemporary, (IsPhantom || (linkPart.Flags & PrimFlags.Phantom) != 0), linkPart.VolumeDetectActive, true);

                // If the added SOP is physical, also tell the physics engine about the link relationship.
                if (linkPart.PhysActor != null && m_rootPart.PhysActor != null && m_rootPart.PhysActor.IsPhysical)
                {
                    linkPart.PhysActor.link(m_rootPart.PhysActor);
                    this.Scene.PhysicsScene.AddPhysicsActorTaint(linkPart.PhysActor);
                }

                linkPart.LinkNum = linkNum++;
                linkPart.UpdatePrimFlags(UsesPhysics, IsTemporary, IsPhantom, IsVolumeDetect, false);

                // Get a list of the SOP's in the old group in order of their linknum's.
                SceneObjectPart[] ogParts = objectGroup.Parts;
                Array.Sort(ogParts, delegate(SceneObjectPart a, SceneObjectPart b)
                        {
                            return a.LinkNum - b.LinkNum;
                        });

                // Add each of the SOP's from the old linkset to our linkset
                for (int i = 0; i < ogParts.Length; i++)
                {
                    SceneObjectPart part = ogParts[i];
                    if (part.UUID != objectGroup.m_rootPart.UUID)
                    {
                        LinkNonRootPart(part, oldGroupPosition, oldRootRotation, linkNum++);

                        // Update the physics flags for the newly added SOP
                        // (Is this necessary? LinkNonRootPart() has already called UpdatePrimFlags but with different flags!??)
                        part.UpdatePrimFlags(grpusephys, grptemporary, (IsPhantom || (part.Flags & PrimFlags.Phantom) != 0), part.VolumeDetectActive, true);

                        // If the added SOP is physical, also tell the physics engine about the link relationship.
                        if (part.PhysActor != null && m_rootPart.PhysActor != null && m_rootPart.PhysActor.IsPhysical)
                        {
                            part.PhysActor.link(m_rootPart.PhysActor);
                            this.Scene.PhysicsScene.AddPhysicsActorTaint(part.PhysActor);
                        }
                    }
                    part.ClearUndoState();
                }
            }

            // Now that we've aquired all of the old SOG's parts, remove the old SOG from the scene.
            m_scene.UnlinkSceneObject(objectGroup, true);
            objectGroup.IsDeleted = true;

            objectGroup.m_parts.Clear();
            
            // Can't do this yet since backup still makes use of the root part without any synchronization
//            objectGroup.m_rootPart = null;

            // If linking prims with different permissions, fix them
            AdjustChildPrimPermissions();

            AttachToBackup();

            // Here's the deal, this is ABSOLUTELY CRITICAL so the physics scene gets the update about the 
            // position of linkset prims.  IF YOU CHANGE THIS, YOU MUST TEST colliding with just linked and 
            // unmoved prims!
            ResetChildPrimPhysicsPositions();

            if (m_rootPart.PhysActor != null)
                m_rootPart.PhysActor.Building = false;

            //HasGroupChanged = true;
            //ScheduleGroupForFullUpdate();
        }

        /// <summary>
        /// Delink the given prim from this group.  The delinked prim is established as
        /// an independent SceneObjectGroup.
        /// </summary>
        /// <remarks>
        /// FIXME: This method should not be called directly since it bypasses update locking, allowing a potential race
        /// condition.  But currently there is no
        /// alternative method that does take a lonk to delink a single prim.
        /// </remarks>
        /// <param name="partID"></param>
        /// <returns>The object group of the newly delinked prim.  Null if part could not be found</returns>
        public SceneObjectGroup DelinkFromGroup(uint partID)
        {
            return DelinkFromGroup(partID, true);
        }

        /// <summary>
        /// Delink the given prim from this group.  The delinked prim is established as
        /// an independent SceneObjectGroup.
        /// </summary>
        /// <remarks>
        /// FIXME: This method should not be called directly since it bypasses update locking, allowing a potential race
        /// condition.  But currently there is no
        /// alternative method that does take a lonk to delink a single prim.
        /// </remarks>
        /// <param name="partID"></param>
        /// <param name="sendEvents"></param>
        /// <returns>The object group of the newly delinked prim.  Null if part could not be found</returns>
        public SceneObjectGroup DelinkFromGroup(uint partID, bool sendEvents)
        {
            SceneObjectPart linkPart = GetPart(partID);

            if (linkPart != null)
            {
                return DelinkFromGroup(linkPart, sendEvents);
            }
            else
            {
                m_log.WarnFormat("[SCENE OBJECT GROUP]: " +
                                 "DelinkFromGroup(): Child prim {0} not found in object {1}, {2}",
                                 partID, LocalId, UUID);

                return null;
            }
        }

        /// <summary>
        /// Delink the given prim from this group.  The delinked prim is established as
        /// an independent SceneObjectGroup.
        /// </summary>
        /// <remarks>
        /// FIXME: This method should not be called directly since it bypasses update locking, allowing a potential race
        /// condition.  But currently there is no
        /// alternative method that does take a lock to delink a single prim.
        /// </remarks>
        /// <param name="partID"></param>
        /// <param name="sendEvents"></param>
        /// <returns>The object group of the newly delinked prim.</returns>
        public SceneObjectGroup DelinkFromGroup(SceneObjectPart linkPart, bool sendEvents)
        {
//                m_log.DebugFormat(
//                    "[SCENE OBJECT GROUP]: Delinking part {0}, {1} from group with root part {2}, {3}",
//                    linkPart.Name, linkPart.UUID, RootPart.Name, RootPart.UUID);

            if (m_rootPart.PhysActor != null)
                m_rootPart.PhysActor.Building = true;

            linkPart.ClearUndoState();

            Vector3 worldPos = linkPart.GetWorldPosition();
            Quaternion worldRot = linkPart.GetWorldRotation();

            // Remove the part from this object
            lock (m_parts.SyncRoot)
            {
                m_parts.Remove(linkPart.UUID);

                SceneObjectPart[] parts = m_parts.GetArray();

                // Rejigger the linknum's of the remaining SOP's to fill any gap
                if (parts.Length == 1 && RootPart != null)
                {
                    // Single prim left
                    RootPart.LinkNum = 0;
                }
                else
                {
                    for (int i = 0; i < parts.Length; i++)
                    {
                        SceneObjectPart part = parts[i];
                        if (part.LinkNum > linkPart.LinkNum)
                            part.LinkNum--;
                    }
                }
            }

            linkPart.ParentID = 0;
            linkPart.LinkNum = 0;

            PhysicsActor linkPartPa = linkPart.PhysActor;

            // Remove the SOP from the physical scene.
            // If the new SOG is physical, it is re-created later.
            // (There is a problem here in that we have not yet told the physics
            //    engine about the delink. Someday, linksets should be made first
            //    class objects in the physics engine interface).
            if (linkPartPa != null)
                m_scene.PhysicsScene.RemovePrim(linkPartPa);

            // We need to reset the child part's position
            // ready for life as a separate object after being a part of another object

            /* This commented out code seems to recompute what GetWorldPosition already does.
             * Replace with a call to GetWorldPosition (before unlinking)
            Quaternion parentRot = m_rootPart.RotationOffset;
            Vector3 axPos = linkPart.OffsetPosition;
            axPos *= parentRot;
            linkPart.OffsetPosition = new Vector3(axPos.X, axPos.Y, axPos.Z);
            linkPart.GroupPosition = AbsolutePosition + linkPart.OffsetPosition;
            linkPart.OffsetPosition = new Vector3(0, 0, 0);
             */
            linkPart.GroupPosition = worldPos;
            linkPart.OffsetPosition = Vector3.Zero;
            linkPart.RotationOffset = worldRot;

            // Create a new SOG to go around this unlinked and unattached SOP
            SceneObjectGroup objectGroup = new SceneObjectGroup(linkPart);

            m_scene.AddNewSceneObject(objectGroup, true);

            if (sendEvents)
                linkPart.TriggerScriptChangedEvent(Changed.LINK);

            linkPart.Rezzed = RootPart.Rezzed;

            // When we delete a group, we currently have to force persist to the database if the object id has changed
            // (since delete works by deleting all rows which have a given object id)

            // this is as it seems to be in sl now
            if(linkPart.PhysicsShapeType == (byte)PhysShapeType.none)
                linkPart.PhysicsShapeType = linkPart.DefaultPhysicsShapeType(); // root prims can't have type none for now

            if (m_rootPart.PhysActor != null)
                m_rootPart.PhysActor.Building = false;

            objectGroup.HasGroupChangedDueToDelink = true;

            return objectGroup;
        }

        /// <summary>
        /// Stop this object from being persisted over server restarts.
        /// </summary>
        /// <param name="objectGroup"></param>
        public virtual void DetachFromBackup()
        {
            if (m_scene != null)
                m_scene.SceneGraph.FireDetachFromBackup(this);
            if (m_isBackedUp && Scene != null)
                m_scene.EventManager.OnBackup -= ProcessBackup;
            
            m_isBackedUp = false;
        }

        // This links an SOP from a previous linkset into my linkset.
        // The trick is that the SOP's position and rotation are relative to the old root SOP's
        //    so we are passed in the position and rotation of the old linkset so this can
        //    unjigger this SOP's position and rotation from the previous linkset and
        //    then make them relative to my linkset root.
        private void LinkNonRootPart(SceneObjectPart part, Vector3 oldGroupPosition, Quaternion oldGroupRotation, int linkNum)
        {
            Quaternion parentRot = oldGroupRotation;
            Quaternion oldRot = part.RotationOffset;

            // Move our position to not be relative to the old parent
            Vector3 axPos = part.OffsetPosition;
            axPos *= parentRot;
            part.OffsetPosition = axPos;
            Vector3 newPos = oldGroupPosition + part.OffsetPosition;
            part.GroupPosition = newPos;
            part.OffsetPosition = Vector3.Zero;

            // Compution our rotation to be not relative to the old parent
            Quaternion worldRot = parentRot * oldRot;
            part.RotationOffset = worldRot;

            // Add this SOP to our linkset
            part.SetParent(this);
            part.ParentID = m_rootPart.LocalId;
            m_parts.Add(part.UUID, part);

            part.LinkNum = linkNum;

            // Compute the new position of this SOP relative to the group position
            part.OffsetPosition = newPos - AbsolutePosition;

            // (radams1 20120711: I don't know why part.OffsetPosition is set multiple times.
            //   It would have the affect of setting the physics engine position multiple 
            //   times. In theory, that is not necessary but I don't have a good linkset
            //   test to know that cleaning up this code wouldn't break things.)

            // Rotate the relative position by the rotation of the group
            Quaternion rootRotation = m_rootPart.RotationOffset;
            Vector3 pos = part.OffsetPosition;
            pos *= Quaternion.Conjugate(rootRotation);
            part.OffsetPosition = pos;

            // Compute the SOP's rotation relative to the rotation of the group.
            parentRot = m_rootPart.RotationOffset;
            oldRot = part.RotationOffset;
            Quaternion newRot = Quaternion.Conjugate(parentRot) * worldRot;
            part.RotationOffset = newRot;

            // Since this SOP's state has changed, push those changes into the physics engine
            //    and the simulator.
            // done on caller
//            part.UpdatePrimFlags(UsesPhysics, IsTemporary, IsPhantom, IsVolumeDetect, false);
        }

        /// <summary>
        /// If object is physical, apply force to move it around
        /// If object is not physical, just put it at the resulting location
        /// </summary>
        /// <param name="offset">Always seems to be 0,0,0, so ignoring</param>
        /// <param name="pos">New position.  We do the math here to turn it into a force</param>
        /// <param name="remoteClient"></param>
        public void GrabMovement(Vector3 offset, Vector3 pos, IClientAPI remoteClient)
        {
            if (m_scene.EventManager.TriggerGroupMove(UUID, pos))
            {
                PhysicsActor pa = m_rootPart.PhysActor;

                if (pa != null)
                {
                    if (pa.IsPhysical)
                    {
                        if (!m_rootPart.BlockGrab)
                        {
/*                            Vector3 llmoveforce = pos - AbsolutePosition;
                            Vector3 grabforce = llmoveforce;
                            grabforce = (grabforce / 10) * pa.Mass;
 */
                            // empirically convert distance diference to a impulse
                            Vector3 grabforce = pos - AbsolutePosition;
                            grabforce = grabforce * (pa.Mass/ 10.0f);
                            pa.AddForce(grabforce, false);
                            m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
                        }
                    }
                    else
                    {
                        //NonPhysicalGrabMovement(pos);
                    }
                }
                else
                {
                    //NonPhysicalGrabMovement(pos);
                }
            }
        }

        public void NonPhysicalGrabMovement(Vector3 pos)
        {
            AbsolutePosition = pos;
            m_rootPart.SendTerseUpdateToAllClients();
        }

        /// <summary>
        /// If object is physical, prepare for spinning torques (set flag to save old orientation)
        /// </summary>
        /// <param name="rotation">Rotation.  We do the math here to turn it into a torque</param>
        /// <param name="remoteClient"></param>
        public void SpinStart(IClientAPI remoteClient)
        {
            if (m_scene.EventManager.TriggerGroupSpinStart(UUID))
            {
                PhysicsActor pa = m_rootPart.PhysActor;

                if (pa != null)
                {
                    if (pa.IsPhysical)
                    {
                        m_rootPart.IsWaitingForFirstSpinUpdatePacket = true;
                    }
                }
            }
        }

        /// <summary>
        /// If object is physical, apply torque to spin it around
        /// </summary>
        /// <param name="rotation">Rotation.  We do the math here to turn it into a torque</param>
        /// <param name="remoteClient"></param>
        public void SpinMovement(Quaternion newOrientation, IClientAPI remoteClient)
        {
            // The incoming newOrientation, sent by the client, "seems" to be the 
            // desired target orientation. This needs further verification; in particular, 
            // one would expect that the initial incoming newOrientation should be
            // fairly close to the original prim's physical orientation, 
            // m_rootPart.PhysActor.Orientation. This however does not seem to be the
            // case (might just be an issue with different quaternions representing the
            // same rotation, or it might be a coordinate system issue).
            //
            // Since it's not clear what the relationship is between the PhysActor.Orientation
            // and the incoming orientations sent by the client, we take an alternative approach
            // of calculating the delta rotation between the orientations being sent by the 
            // client. (Since a spin is invoked by ctrl+shift+drag in the client, we expect
            // a steady stream of several new orientations coming in from the client.)
            // This ensures that the delta rotations are being calculated from self-consistent
            // pairs of old/new rotations. Given the delta rotation, we apply a torque around
            // the delta rotation axis, scaled by the object mass times an arbitrary scaling
            // factor (to ensure the resulting torque is not "too strong" or "too weak").
            // 
            // Ideally we need to calculate (probably iteratively) the exact torque or series
            // of torques needed to arrive exactly at the destination orientation. However, since 
            // it is not yet clear how to map the destination orientation (provided by the viewer)
            // into PhysActor orientations (needed by the physics engine), we omit this step. 
            // This means that the resulting torque will at least be in the correct direction, 
            // but it will result in over-shoot or under-shoot of the target orientation.
            // For the end user, this means that ctrl+shift+drag can be used for relative,
            // but not absolute, adjustments of orientation for physical prims.
            if (m_scene.EventManager.TriggerGroupSpin(UUID, newOrientation))
            {
                PhysicsActor pa = m_rootPart.PhysActor;

                if (pa != null)
                {
                    if (pa.IsPhysical)
                    {
                        if (m_rootPart.IsWaitingForFirstSpinUpdatePacket)
                        {
                            // first time initialization of "old" orientation for calculation of delta rotations
                            m_rootPart.SpinOldOrientation = newOrientation;
                            m_rootPart.IsWaitingForFirstSpinUpdatePacket = false;
                        }
                        else
                        {
                          // save and update old orientation
                          Quaternion old = m_rootPart.SpinOldOrientation;
                          m_rootPart.SpinOldOrientation = newOrientation;
                          //m_log.Error("[SCENE OBJECT GROUP]: Old orientation is " + old);
                          //m_log.Error("[SCENE OBJECT GROUP]: Incoming new orientation is " + newOrientation);

                          // compute difference between previous old rotation and new incoming rotation
                          Quaternion minimalRotationFromQ1ToQ2 = Quaternion.Inverse(old) * newOrientation;

                          float rotationAngle;
                          Vector3 rotationAxis;
                          minimalRotationFromQ1ToQ2.GetAxisAngle(out rotationAxis, out rotationAngle);
                          rotationAxis.Normalize();

                          //m_log.Error("SCENE OBJECT GROUP]: rotation axis is " + rotationAxis);
                          Vector3 spinforce = new Vector3(rotationAxis.X, rotationAxis.Y, rotationAxis.Z);
                          spinforce = (spinforce/8) * pa.Mass; // 8 is an arbitrary torque scaling factor
                          pa.AddAngularForce(spinforce,true);
                          m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
                        }
                    }
                    else
                    {
                        //NonPhysicalSpinMovement(pos);
                    }
                }
                else
                {
                    //NonPhysicalSpinMovement(pos);
                }
            }
        }

        /// <summary>
        /// Set the name of a prim
        /// </summary>
        /// <param name="name"></param>
        /// <param name="localID"></param>
        public void SetPartName(string name, uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.Name = name;
            }
        }

        public void SetPartDescription(string des, uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.Description = des;
            }
        }

        public void SetPartText(string text, uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.SetText(text);
            }
        }

        public void SetPartText(string text, UUID partID)
        {
            SceneObjectPart part = GetPart(partID);
            if (part != null)
            {
                part.SetText(text);
            }
        }

        public string GetPartName(uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                return part.Name;
            }
            return String.Empty;
        }

        public string GetPartDescription(uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                return part.Description;
            }
            return String.Empty;
        }

        /// <summary>
        /// Update prim flags for this group.
        /// </summary>
        /// <param name="localID"></param>
        /// <param name="UsePhysics"></param>
        /// <param name="SetTemporary"></param>
        /// <param name="SetPhantom"></param>
        /// <param name="SetVolumeDetect"></param>
        public void UpdatePrimFlags(uint localID, bool UsePhysics, bool SetTemporary, bool SetPhantom, bool SetVolumeDetect)
        {
            HasGroupChanged = true;

            SceneObjectPart selectionPart = GetPart(localID);

            if (SetTemporary && Scene != null)
            {
                DetachFromBackup();
                // Remove from database and parcel prim count
                //
                m_scene.DeleteFromStorage(UUID);
                m_scene.EventManager.TriggerParcelPrimCountTainted();
            }

            if (selectionPart != null)
            {
                SceneObjectPart[] parts = m_parts.GetArray();
                
                if (Scene != null)
                {
                    for (int i = 0; i < parts.Length; i++)
                    {
                        SceneObjectPart part = parts[i];
                        if (part.Scale.X > m_scene.m_maxPhys ||
                            part.Scale.Y > m_scene.m_maxPhys ||
                            part.Scale.Z > m_scene.m_maxPhys )
                        {
                            UsePhysics = false; // Reset physics
                            break;
                        }
                    }
                }

                if (parts.Length > 1)
                {
                    m_rootPart.UpdatePrimFlags(UsePhysics, SetTemporary, SetPhantom, SetVolumeDetect, true);

                    for (int i = 0; i < parts.Length; i++)
                    {

                        if (parts[i].UUID != m_rootPart.UUID)
                            parts[i].UpdatePrimFlags(UsePhysics, SetTemporary, SetPhantom, SetVolumeDetect, true);
                    }

                    if (m_rootPart.PhysActor != null)
                        m_rootPart.PhysActor.Building = false;
                }
                else
                    m_rootPart.UpdatePrimFlags(UsePhysics, SetTemporary, SetPhantom, SetVolumeDetect, false);
            }
        }

        public void UpdateExtraParam(uint localID, ushort type, bool inUse, byte[] data)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.UpdateExtraParam(type, inUse, data);
            }
        }



        /// <summary>
        /// Gets the number of parts
        /// </summary>
        /// <returns></returns>
        public int GetPartCount()
        {
            return Parts.Count();
        }

        /// <summary>
        /// Update the texture entry for this part
        /// </summary>
        /// <param name="localID"></param>
        /// <param name="textureEntry"></param>
        public void UpdateTextureEntry(uint localID, byte[] textureEntry)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.UpdateTextureEntry(textureEntry);
            }
        }

        public void AdjustChildPrimPermissions()
        {
            uint newOwnerMask = (uint)PermissionMask.All & 0xfffffff8; // Mask folded bits
            uint foldedPerms = RootPart.OwnerMask & 3;

            ForEachPart(part =>
            {
                newOwnerMask &= part.BaseMask;
                if (part != RootPart)
                    part.ClonePermissions(RootPart);
            });

            uint lockMask = ~(uint)PermissionMask.Move;
            uint lockBit = RootPart.OwnerMask & (uint)PermissionMask.Move;
            RootPart.OwnerMask = (RootPart.OwnerMask & lockBit) | ((newOwnerMask | foldedPerms) & lockMask);
            RootPart.ScheduleFullUpdate();
        }

        public void UpdatePermissions(UUID AgentID, byte field, uint localID,
                uint mask, byte addRemTF)
        {
            RootPart.UpdatePermissions(AgentID, field, localID, mask, addRemTF);

            bool god = Scene.Permissions.IsGod(AgentID);

            if (field == 1 && god)
            {
                ForEachPart(part =>
                {
                    part.BaseMask = RootPart.BaseMask;
                });
            }

            AdjustChildPrimPermissions();

            if (field == 1 && god) // Base mask was set. Update all child part inventories
            {
                foreach (SceneObjectPart part in Parts)
                    part.Inventory.ApplyGodPermissions(RootPart.BaseMask);
            }

            HasGroupChanged = true;

            // Send the group's properties to all clients once all parts are updated
            IClientAPI client;
            if (Scene.TryGetClient(AgentID, out client))
                SendPropertiesToClient(client);
        }

        #endregion

        #region Shape

        /// <summary>
        ///
        /// </summary>
        /// <param name="shapeBlock"></param>
        public void UpdateShape(ObjectShapePacket.ObjectDataBlock shapeBlock, uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                part.UpdateShape(shapeBlock);

                PhysicsActor pa = m_rootPart.PhysActor;

                if (pa != null)
                    m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
            }
        }

        #endregion

        #region Resize

        /// <summary>
        /// Resize the entire group of prims.
        /// </summary>
        /// <param name="scale"></param>
        public void GroupResize(Vector3 scale)
        {
//            m_log.DebugFormat(
//                "[SCENE OBJECT GROUP]: Group resizing {0} {1} from {2} to {3}", Name, LocalId, RootPart.Scale, scale);

            PhysicsActor pa = m_rootPart.PhysActor;

            if (Scene != null)
            {
                scale.X = Math.Max(Scene.m_minNonphys, Math.Min(Scene.m_maxNonphys, scale.X));
                scale.Y = Math.Max(Scene.m_minNonphys, Math.Min(Scene.m_maxNonphys, scale.Y));
                scale.Z = Math.Max(Scene.m_minNonphys, Math.Min(Scene.m_maxNonphys, scale.Z));
    
                if (pa != null && pa.IsPhysical)
                {
                    scale.X = Math.Max(Scene.m_minPhys, Math.Min(Scene.m_maxPhys, scale.X));
                    scale.Y = Math.Max(Scene.m_minPhys, Math.Min(Scene.m_maxPhys, scale.Y));
                    scale.Z = Math.Max(Scene.m_minPhys, Math.Min(Scene.m_maxPhys, scale.Z));
                }
            }

            float x = (scale.X / RootPart.Scale.X);
            float y = (scale.Y / RootPart.Scale.Y);
            float z = (scale.Z / RootPart.Scale.Z);

            SceneObjectPart[] parts = m_parts.GetArray();

            if (Scene != null & (x > 1.0f || y > 1.0f || z > 1.0f))
            {
                for (int i = 0; i < parts.Length; i++)
                {
                    SceneObjectPart obPart = parts[i];
                    if (obPart.UUID != m_rootPart.UUID)
                    {
                        Vector3 oldSize = new Vector3(obPart.Scale);

                        float f = 1.0f;
                        float a = 1.0f;

                        if (pa != null && pa.IsPhysical)
                        {
                            if (oldSize.X * x > Scene.m_maxPhys)
                            {
                                f = m_scene.m_maxPhys / oldSize.X;
                                a = f / x;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.X * x < Scene.m_minPhys)
                            {
                                f = m_scene.m_minPhys / oldSize.X;
                                a = f / x;
                                x *= a;
                                y *= a;
                                z *= a;
                            }

                            if (oldSize.Y * y > Scene.m_maxPhys)
                            {
                                f = m_scene.m_maxPhys / oldSize.Y;
                                a = f / y;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.Y * y < Scene.m_minPhys)
                            {
                                f = m_scene.m_minPhys / oldSize.Y;
                                a = f / y;
                                x *= a;
                                y *= a;
                                z *= a;
                            }

                            if (oldSize.Z * z > Scene.m_maxPhys)
                            {
                                f = m_scene.m_maxPhys / oldSize.Z;
                                a = f / z;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.Z * z < Scene.m_minPhys)
                            {
                                f = m_scene.m_minPhys / oldSize.Z;
                                a = f / z;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                        }
                        else
                        {
                            if (oldSize.X * x > Scene.m_maxNonphys)
                            {
                                f = m_scene.m_maxNonphys / oldSize.X;
                                a = f / x;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.X * x < Scene.m_minNonphys)
                            {
                                f = m_scene.m_minNonphys / oldSize.X;
                                a = f / x;
                                x *= a;
                                y *= a;
                                z *= a;
                            }

                            if (oldSize.Y * y > Scene.m_maxNonphys)
                            {
                                f = m_scene.m_maxNonphys / oldSize.Y;
                                a = f / y;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.Y * y < Scene.m_minNonphys)
                            {
                                f = m_scene.m_minNonphys / oldSize.Y;
                                a = f / y;
                                x *= a;
                                y *= a;
                                z *= a;
                            }

                            if (oldSize.Z * z > Scene.m_maxNonphys)
                            {
                                f = m_scene.m_maxNonphys / oldSize.Z;
                                a = f / z;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                            else if (oldSize.Z * z < Scene.m_minNonphys)
                            {
                                f = m_scene.m_minNonphys / oldSize.Z;
                                a = f / z;
                                x *= a;
                                y *= a;
                                z *= a;
                            }
                        }
                    }
                }
            }

            Vector3 prevScale = RootPart.Scale;
            prevScale.X *= x;
            prevScale.Y *= y;
            prevScale.Z *= z;

            RootPart.Resize(prevScale);

            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart obPart = parts[i];

                if (obPart.UUID != m_rootPart.UUID)
                {
                    Vector3 currentpos = new Vector3(obPart.OffsetPosition);
                    currentpos.X *= x;
                    currentpos.Y *= y;
                    currentpos.Z *= z;

                    Vector3 newSize = new Vector3(obPart.Scale);
                    newSize.X *= x;
                    newSize.Y *= y;
                    newSize.Z *= z;

                    obPart.Resize(newSize);
                    obPart.UpdateOffSet(currentpos);
                }

                HasGroupChanged = true;
                m_rootPart.TriggerScriptChangedEvent(Changed.SCALE);
                ScheduleGroupForTerseUpdate();
            }
        }

        #endregion

        #region Position

        /// <summary>
        /// Move this scene object
        /// </summary>
        /// <param name="pos"></param>
        public void UpdateGroupPosition(Vector3 pos)
        {
            if (m_scene.EventManager.TriggerGroupMove(UUID, pos))
            {
                if (IsAttachment)
                {
                    m_rootPart.AttachedPos = pos;
                }

                if (RootPart.GetStatusSandbox())
                {
                    if (Util.GetDistanceTo(RootPart.StatusSandboxPos, pos) > 10)
                    {
                        RootPart.ScriptSetPhysicsStatus(false);
                        pos = AbsolutePosition;
                        Scene.SimChat(Utils.StringToBytes("Hit Sandbox Limit"),
                              ChatTypeEnum.DebugChannel, 0x7FFFFFFF, RootPart.AbsolutePosition, Name, UUID, false);
                    }
                }

                AbsolutePosition = pos;
                HasGroupChanged = true;
            }

            //we need to do a terse update even if the move wasn't allowed
            // so that the position is reset in the client (the object snaps back)
            RootPart.ScheduleTerseUpdate();
        }

        /// <summary>
        /// Update the position of a single part of this scene object
        /// </summary>
        /// <param name="pos"></param>
        /// <param name="localID"></param>
        /// 

        public void UpdateSinglePosition(Vector3 pos, uint localID)
        {
            SceneObjectPart part = GetPart(localID);

            if (part != null)
            {
// unlock parts position change
                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = true;

                if (part.UUID == m_rootPart.UUID)
                {
                    UpdateRootPosition(pos);
                }
                else
                {
                    part.UpdateOffSet(pos);
                }

                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = false;

                HasGroupChanged = true;
            }
        }

        /// <summary>
        /// Update just the root prim position in a linkset
        /// </summary>
        /// <param name="pos"></param>
        public void UpdateRootPosition(Vector3 pos)
        {
            // needs to be called with phys building true
            Vector3 newPos = new Vector3(pos.X, pos.Y, pos.Z);
            Vector3 oldPos =
                new Vector3(AbsolutePosition.X + m_rootPart.OffsetPosition.X,
                              AbsolutePosition.Y + m_rootPart.OffsetPosition.Y,
                              AbsolutePosition.Z + m_rootPart.OffsetPosition.Z);
            Vector3 diff = oldPos - newPos;
            Vector3 axDiff = new Vector3(diff.X, diff.Y, diff.Z);
            Quaternion partRotation = m_rootPart.RotationOffset;
            axDiff *= Quaternion.Inverse(partRotation);
            diff = axDiff;

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart obPart = parts[i];
                if (obPart.UUID != m_rootPart.UUID)
                    obPart.OffsetPosition = obPart.OffsetPosition + diff;
            }

            AbsolutePosition = newPos;

            HasGroupChanged = true;
            if (m_rootPart.Undoing)
            {
                ScheduleGroupForFullUpdate();
            }
            else
            {
                ScheduleGroupForTerseUpdate();
            }
        }

        #endregion

        #region Rotation

        /// <summary>
        /// Update the rotation of the group.
        /// </summary>
        /// <param name="rot"></param>
        public void UpdateGroupRotationR(Quaternion rot)
        {
            m_rootPart.UpdateRotation(rot);
        
/* this is done by rootpart RotationOffset set called by UpdateRotation
            PhysicsActor actor = m_rootPart.PhysActor;
            if (actor != null)
            {
                actor.Orientation = m_rootPart.RotationOffset;
                m_scene.PhysicsScene.AddPhysicsActorTaint(actor);
            }
*/
            HasGroupChanged = true;
            ScheduleGroupForTerseUpdate();
        }

        /// <summary>
        /// Update the position and rotation of a group simultaneously.
        /// </summary>
        /// <param name="pos"></param>
        /// <param name="rot"></param>
        public void UpdateGroupRotationPR(Vector3 pos, Quaternion rot)
        {
            m_rootPart.UpdateRotation(rot);

            PhysicsActor actor = m_rootPart.PhysActor;
            if (actor != null)
            {
                actor.Orientation = m_rootPart.RotationOffset;
                m_scene.PhysicsScene.AddPhysicsActorTaint(actor);
            }

            if (IsAttachment)
            {
                m_rootPart.AttachedPos = pos;
            }

            AbsolutePosition = pos;

            HasGroupChanged = true;
            ScheduleGroupForTerseUpdate();
        }

        /// <summary>
        /// Update the rotation of a single prim within the group.
        /// </summary>
        /// <param name="rot"></param>
        /// <param name="localID"></param>
        public void UpdateSingleRotation(Quaternion rot, uint localID)
        {
            SceneObjectPart part = GetPart(localID);

            SceneObjectPart[] parts = m_parts.GetArray();

            if (part != null)
            {
                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = true;

                if (part.UUID == m_rootPart.UUID)
                {
                    UpdateRootRotation(rot);
                }
                else
                {
                    part.UpdateRotation(rot);
                }

                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = false;
            }
        }

        /// <summary>
        /// Update the position and rotation simultaneously of a single prim within the group.
        /// </summary>
        /// <param name="rot"></param>
        /// <param name="localID"></param>
        public void UpdateSingleRotation(Quaternion rot, Vector3 pos, uint localID)
        {
            SceneObjectPart part = GetPart(localID);
            if (part != null)
            {
                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = true;

                if (part.UUID == m_rootPart.UUID)
                {
                    UpdateRootRotation(rot);
                    AbsolutePosition = pos;
                }
                else
                {
                    part.UpdateRotation(rot);
                    part.OffsetPosition = pos;
                }

                if (m_rootPart.PhysActor != null)
                    m_rootPart.PhysActor.Building = false;
            }
        }

        /// <summary>
        /// Update the rotation of just the root prim of a linkset.
        /// </summary>
        /// <param name="rot"></param>
        public void UpdateRootRotation(Quaternion rot)
        {
            // needs to be called with phys building true
            Quaternion axRot = rot;
            Quaternion oldParentRot = m_rootPart.RotationOffset;

            //Don't use UpdateRotation because it schedules an update prematurely
            m_rootPart.RotationOffset = rot;

            PhysicsActor pa = m_rootPart.PhysActor;

            if (pa != null)
            {
                pa.Orientation = m_rootPart.RotationOffset;
                m_scene.PhysicsScene.AddPhysicsActorTaint(pa);
            }

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart prim = parts[i];
                if (prim.UUID != m_rootPart.UUID)
                {
                    Quaternion NewRot = oldParentRot * prim.RotationOffset;
                    NewRot = Quaternion.Inverse(axRot) * NewRot;
                    prim.RotationOffset = NewRot;

                    Vector3 axPos = prim.OffsetPosition;

                    axPos *= oldParentRot;
                    axPos *= Quaternion.Inverse(axRot);
                    prim.OffsetPosition = axPos;
                }
            }

            HasGroupChanged = true;
            ScheduleGroupForFullUpdate();
        }

        private enum updatetype :int
        {
            none = 0,
            partterse = 1,
            partfull = 2,
            groupterse = 3,
            groupfull = 4
        }

        public void doChangeObject(SceneObjectPart part, ObjectChangeData data)
        {
            // TODO  this still as excessive *.Schedule*Update()s

            if (part != null && part.ParentGroup != null)
            {
                ObjectChangeType change = data.change;
                bool togroup = ((change & ObjectChangeType.Group) != 0);
                //                bool uniform = ((what & ObjectChangeType.UniformScale) != 0);  not in use

                SceneObjectGroup group = part.ParentGroup;
                PhysicsActor pha = group.RootPart.PhysActor;

                updatetype updateType = updatetype.none;

                if (togroup)
                {
                    // related to group
                    if ((change & (ObjectChangeType.Rotation | ObjectChangeType.Position)) != 0)
                    {
                        if ((change & ObjectChangeType.Rotation) != 0)
                        {
                            group.RootPart.UpdateRotation(data.rotation);
                            updateType = updatetype.none;
                        }
                        if ((change & ObjectChangeType.Position) != 0)
                        {
                            if (IsAttachment || m_scene.Permissions.CanObjectEntry(group.UUID, false, data.position))
                                UpdateGroupPosition(data.position);
                            updateType = updatetype.groupterse;
                        }
                        else
                        // ugly rotation update of all parts
                        {
                            group.ResetChildPrimPhysicsPositions();
                        }

                    }
                    if ((change & ObjectChangeType.Scale) != 0)
                    {
                        if (pha != null)
                            pha.Building = true;

                        group.GroupResize(data.scale);
                        updateType = updatetype.none;

                        if (pha != null)
                            pha.Building = false;
                    }
                }
                else
                {
                    // related to single prim in a link-set ( ie group)
                    if (pha != null)
                        pha.Building = true;

                    // root part is special
                    // parts offset positions or rotations need to change also

                    if (part == group.RootPart)
                    {
                        if ((change & ObjectChangeType.Rotation) != 0)
                            group.UpdateRootRotation(data.rotation);
                        if ((change & ObjectChangeType.Position) != 0)
                            group.UpdateRootPosition(data.position);
                        if ((change & ObjectChangeType.Scale) != 0)
                            part.Resize(data.scale);
                    }
                    else
                    {
                        if ((change & ObjectChangeType.Position) != 0)
                        {
                            part.OffsetPosition = data.position;
                            updateType = updatetype.partterse;
                        }
                        if ((change & ObjectChangeType.Rotation) != 0)
                        {
                            part.UpdateRotation(data.rotation);
                            updateType = updatetype.none;
                        }
                        if ((change & ObjectChangeType.Scale) != 0)
                        {
                            part.Resize(data.scale);
                            updateType = updatetype.none;
                        }
                    }

                    if (pha != null)
                        pha.Building = false;
                }

                if (updateType != updatetype.none)
                {
                    group.HasGroupChanged = true;

                    switch (updateType)
                    {
                        case updatetype.partterse:
                            part.ScheduleTerseUpdate();
                            break;
                        case updatetype.partfull:
                            part.ScheduleFullUpdate();
                            break;
                        case updatetype.groupterse:
                            group.ScheduleGroupForTerseUpdate();
                            break;
                        case updatetype.groupfull:
                            group.ScheduleGroupForFullUpdate();
                            break;
                        default:
                            break;
                    }
                }
            }
        }

        #endregion

        internal void SetAxisRotation(int axis, int rotate10)
        {
            bool setX = false;
            bool setY = false;
            bool setZ = false;

            int xaxis = 2;
            int yaxis = 4;
            int zaxis = 8;

            setX = ((axis & xaxis) != 0) ? true : false;
            setY = ((axis & yaxis) != 0) ? true : false;
            setZ = ((axis & zaxis) != 0) ? true : false;

            float setval = (rotate10 > 0) ? 1f : 0f;

            if (setX)
                RootPart.RotationAxis.X = setval;
            if (setY)
                RootPart.RotationAxis.Y = setval;
            if (setZ)
                RootPart.RotationAxis.Z = setval;

            if (setX || setY || setZ)
                RootPart.SetPhysicsAxisRotation();
        }

        public int registerRotTargetWaypoint(Quaternion target, float tolerance)
        {
            scriptRotTarget waypoint = new scriptRotTarget();
            waypoint.targetRot = target;
            waypoint.tolerance = tolerance;
            uint handle = m_scene.AllocateLocalId();
            waypoint.handle = handle;
            lock (m_rotTargets)
            {
                m_rotTargets.Add(handle, waypoint);
            }
            m_scene.AddGroupTarget(this);
            return (int)handle;
        }

        public void unregisterRotTargetWaypoint(int handle)
        {
            lock (m_targets)
            {
                m_rotTargets.Remove((uint)handle);
                if (m_targets.Count == 0)
                    m_scene.RemoveGroupTarget(this);
            }
        }

        public int registerTargetWaypoint(Vector3 target, float tolerance)
        {
            scriptPosTarget waypoint = new scriptPosTarget();
            waypoint.targetPos = target;
            waypoint.tolerance = tolerance;
            uint handle = m_scene.AllocateLocalId();
            waypoint.handle = handle;
            lock (m_targets)
            {
                m_targets.Add(handle, waypoint);
            }
            m_scene.AddGroupTarget(this);
            return (int)handle;
        }
        
        public void unregisterTargetWaypoint(int handle)
        {
            lock (m_targets)
            {
                m_targets.Remove((uint)handle);
                if (m_targets.Count == 0)
                    m_scene.RemoveGroupTarget(this);
            }
        }

        public void checkAtTargets()
        {
            if (m_scriptListens_atTarget || m_scriptListens_notAtTarget)
            {
                if (m_targets.Count > 0)
                {
                    bool at_target = false;
                    //Vector3 targetPos;
                    //uint targetHandle;
                    Dictionary<uint, scriptPosTarget> atTargets = new Dictionary<uint, scriptPosTarget>();
                    lock (m_targets)
                    {
                        foreach (uint idx in m_targets.Keys)
                        {
                            scriptPosTarget target = m_targets[idx];
                            if (Util.GetDistanceTo(target.targetPos, m_rootPart.GroupPosition) <= target.tolerance)
                            {
                                at_target = true;

                                // trigger at_target
                                if (m_scriptListens_atTarget)
                                {
                                    scriptPosTarget att = new scriptPosTarget();
                                    att.targetPos = target.targetPos;
                                    att.tolerance = target.tolerance;
                                    att.handle = target.handle;
                                    atTargets.Add(idx, att);
                                }
                            }
                        }
                    }
                    
                    if (atTargets.Count > 0)
                    {
                        SceneObjectPart[] parts = m_parts.GetArray();
                        uint[] localids = new uint[parts.Length];
                        for (int i = 0; i < parts.Length; i++)
                            localids[i] = parts[i].LocalId;
                        
                        for (int ctr = 0; ctr < localids.Length; ctr++)
                        {
                            foreach (uint target in atTargets.Keys)
                            {
                                scriptPosTarget att = atTargets[target];
                                m_scene.EventManager.TriggerAtTargetEvent(
                                    localids[ctr], att.handle, att.targetPos, m_rootPart.GroupPosition);
                            }
                        }
                        
                        return;
                    }
                    
                    if (m_scriptListens_notAtTarget && !at_target)
                    {
                        //trigger not_at_target
                        SceneObjectPart[] parts = m_parts.GetArray();
                        uint[] localids = new uint[parts.Length];
                        for (int i = 0; i < parts.Length; i++)
                            localids[i] = parts[i].LocalId;
                        
                        for (int ctr = 0; ctr < localids.Length; ctr++)
                        {
                            m_scene.EventManager.TriggerNotAtTargetEvent(localids[ctr]);
                        }
                    }
                }
            }
            if (m_scriptListens_atRotTarget || m_scriptListens_notAtRotTarget)
            {
                if (m_rotTargets.Count > 0)
                {
                    bool at_Rottarget = false;
                    Dictionary<uint, scriptRotTarget> atRotTargets = new Dictionary<uint, scriptRotTarget>();
                    lock (m_rotTargets)
                    {
                        foreach (uint idx in m_rotTargets.Keys)
                        {
                            scriptRotTarget target = m_rotTargets[idx];
                            double angle
                                = Math.Acos(
                                    target.targetRot.X * m_rootPart.RotationOffset.X
                                        + target.targetRot.Y * m_rootPart.RotationOffset.Y
                                        + target.targetRot.Z * m_rootPart.RotationOffset.Z
                                        + target.targetRot.W * m_rootPart.RotationOffset.W)
                                    * 2;
                            if (angle < 0) angle = -angle;
                            if (angle > Math.PI) angle = (Math.PI * 2 - angle);
                            if (angle <= target.tolerance)
                            {
                                // trigger at_rot_target
                                if (m_scriptListens_atRotTarget)
                                {
                                    at_Rottarget = true;
                                    scriptRotTarget att = new scriptRotTarget();
                                    att.targetRot = target.targetRot;
                                    att.tolerance = target.tolerance;
                                    att.handle = target.handle;
                                    atRotTargets.Add(idx, att);
                                }
                            }
                        }
                    }

                    if (atRotTargets.Count > 0)
                    {
                        SceneObjectPart[] parts = m_parts.GetArray();
                        uint[] localids = new uint[parts.Length];
                        for (int i = 0; i < parts.Length; i++)
                            localids[i] = parts[i].LocalId;

                        for (int ctr = 0; ctr < localids.Length; ctr++)
                        {
                            foreach (uint target in atRotTargets.Keys)
                            {
                                scriptRotTarget att = atRotTargets[target];
                                m_scene.EventManager.TriggerAtRotTargetEvent(
                                    localids[ctr], att.handle, att.targetRot, m_rootPart.RotationOffset);
                            }
                        }

                        return;
                    }

                    if (m_scriptListens_notAtRotTarget && !at_Rottarget)
                    {
                        //trigger not_at_target
                        SceneObjectPart[] parts = m_parts.GetArray();
                        uint[] localids = new uint[parts.Length];
                        for (int i = 0; i < parts.Length; i++)
                            localids[i] = parts[i].LocalId;

                        for (int ctr = 0; ctr < localids.Length; ctr++)
                        {
                            m_scene.EventManager.TriggerNotAtRotTargetEvent(localids[ctr]);
                        }
                    }
                }
            }
        }

        public Vector3 GetGeometricCenter()
        {
            // this is not real geometric center but a average of positions relative to root prim acording to
            // http://wiki.secondlife.com/wiki/llGetGeometricCenter
            // ignoring tortured prims details since sl also seems to ignore
            // so no real use in doing it on physics
            
            Vector3 gc = Vector3.Zero;

            int nparts = m_parts.Count;
            if (nparts <= 1)
                return gc;

            SceneObjectPart[] parts = m_parts.GetArray();
            nparts = parts.Length; // just in case it changed
            if (nparts <= 1)
                return gc;

            Quaternion parentRot = RootPart.RotationOffset;
            Vector3 pPos;

            // average all parts positions
            for (int i = 0; i < nparts; i++)
            {
                // do it directly
                //                gc += parts[i].GetWorldPosition();
                if (parts[i] != RootPart)
                {
                    pPos = parts[i].OffsetPosition;
                    gc += pPos;
                }

            }
            gc /= nparts;

            // relative to root:
//            gc -= AbsolutePosition;
            return gc;
        }

        public float GetMass()
        {
            float retmass = 0f;
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                retmass += parts[i].GetMass();

            return retmass;
        }

        // center of mass of full object
        public Vector3 GetCenterOfMass()
        {
            PhysicsActor pa = RootPart.PhysActor;

            if(((RootPart.Flags & PrimFlags.Physics) !=0) && pa !=null)
            {
                // physics knows better about center of mass of physical prims
                Vector3 tmp = pa.CenterOfMass;
                return tmp;
            }
            
            Vector3 Ptot = Vector3.Zero;
            float totmass = 0f;
            float m;

            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                m = parts[i].GetMass();
                Ptot += parts[i].GetPartCenterOfMass() * m;
                totmass += m;
            }

            if (totmass == 0)
                totmass = 0;
            else
                totmass = 1 / totmass;
            Ptot *= totmass;

            return Ptot;
        }

        /// <summary>
        /// If the object is a sculpt/mesh, retrieve the mesh data for each part and reinsert it into each shape so that
        /// the physics engine can use it.
        /// </summary>
        /// <remarks>
        /// When the physics engine has finished with it, the sculpt data is discarded to save memory.
        /// </remarks>
/*        
        public void CheckSculptAndLoad()
        {
            if (IsDeleted)
                return;

            if ((RootPart.GetEffectiveObjectFlags() & (uint)PrimFlags.Phantom) != 0)
                return;

//            m_log.Debug("Processing CheckSculptAndLoad for {0} {1}", Name, LocalId);

            SceneObjectPart[] parts = m_parts.GetArray();

            for (int i = 0; i < parts.Length; i++)
                parts[i].CheckSculptAndLoad();
        }
*/
        /// <summary>
        /// Set the user group to which this scene object belongs.
        /// </summary>
        /// <param name="GroupID"></param>
        /// <param name="client"></param>
        public void SetGroup(UUID GroupID, IClientAPI client)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];
                part.SetGroup(GroupID, client);
                part.Inventory.ChangeInventoryGroup(GroupID);
            }

            HasGroupChanged = true;
            
            // Don't trigger the update here - otherwise some client issues occur when multiple updates are scheduled
            // for the same object with very different properties.  The caller must schedule the update.
            //ScheduleGroupForFullUpdate();
        }

        public void TriggerScriptChangedEvent(Changed val)
        {
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                parts[i].TriggerScriptChangedEvent(val);
        }

        /// <summary>
        /// Returns a count of the number of scripts in this groups parts.
        /// </summary>
        public int ScriptCount()
        {
            int count = 0;
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                count += parts[i].Inventory.ScriptCount();

            return count;
        }

        /// <summary>
        /// A float the value is a representative execution time in milliseconds of all scripts in the link set.
        /// </summary>
        public float ScriptExecutionTime()
        {
            IScriptModule[] engines = Scene.RequestModuleInterfaces<IScriptModule>();

            if (engines.Length == 0) // No engine at all
                return 0.0f;

            float time = 0.0f;

            // get all the scripts in all parts
            SceneObjectPart[] parts = m_parts.GetArray();
            List<TaskInventoryItem> scripts = new List<TaskInventoryItem>();
            for (int i = 0; i < parts.Length; i++)
            {
                scripts.AddRange(parts[i].Inventory.GetInventoryItems(InventoryType.LSL));
            }
            // extract the UUIDs
            List<UUID> ids = new List<UUID>(scripts.Count);
            foreach (TaskInventoryItem script in scripts)
            {
                if (!ids.Contains(script.ItemID))
                {
                    ids.Add(script.ItemID);
                }
            }
            // Offer the list of script UUIDs to each engine found and accumulate the time
            foreach (IScriptModule e in engines)
            {
                if (e != null)
                {
                    time += e.GetScriptExecutionTime(ids);
                }
            }
            return time;
        }

        /// <summary>
        /// Returns a count of the number of running scripts in this groups parts.
        /// </summary>
        public int RunningScriptCount()
        {
            int count = 0;
            SceneObjectPart[] parts = m_parts.GetArray();
            for (int i = 0; i < parts.Length; i++)
                count += parts[i].Inventory.RunningScriptCount();

            return count;
        }

        /// <summary>
        /// Get a copy of the list of sitting avatars on all prims of this object.
        /// </summary>
        /// <remarks>
        /// This is sorted by the order in which avatars sat down.  If an avatar stands up then all avatars that sat
        /// down after it move one place down the list.
        /// </remarks>
        /// <returns>A list of the sitting avatars.  Returns an empty list if there are no sitting avatars.</returns>
        public List<UUID> GetSittingAvatars()
        {
            lock (m_sittingAvatars)
                return new List<UUID>(m_sittingAvatars);
        }

        /// <summary>
        /// Gets the number of sitting avatars.
        /// </summary>
        /// <remarks>This applies to all sitting avatars whether there is a sit target set or not.</remarks>
        /// <returns></returns>
        public int GetSittingAvatarsCount()
        {
            lock (m_sittingAvatars)
                return m_sittingAvatars.Count;
        }

        public override string ToString()
        {
            return String.Format("{0} {1} ({2})", Name, UUID, AbsolutePosition);
        }

        #region ISceneObject

        public virtual ISceneObject CloneForNewScene()
        {
            SceneObjectGroup sog = Copy(false);
            sog.IsDeleted = false;
            return sog;
        }

        public virtual string ToXml2()
        {
            return SceneObjectSerializer.ToXml2Format(this);
        }

        public virtual string ExtraToXmlString()
        {
            return "<ExtraFromItemID>" + FromItemID.ToString() + "</ExtraFromItemID>";
        }

        public virtual void ExtraFromXmlString(string xmlstr)
        {
            string id = xmlstr.Substring(xmlstr.IndexOf("<ExtraFromItemID>"));
            id = xmlstr.Replace("<ExtraFromItemID>", "");
            id = id.Replace("</ExtraFromItemID>", "");

            UUID uuid = UUID.Zero;
            UUID.TryParse(id, out uuid);

            FromItemID = uuid;
        }

        public void ResetOwnerChangeFlag()
        {
            ForEachPart(delegate(SceneObjectPart part)
            {
                part.ResetOwnerChangeFlag();
            });
        }

        #endregion
    }
}