/*
 * 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.
 */

//#define USE_DRAWSTUFF

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Threading;
using System.IO;
using System.Diagnostics;
using log4net;
using Nini.Config;
using Ode.NET;
#if USE_DRAWSTUFF
using Drawstuff.NET;
#endif 
using OpenSim.Framework;
using OpenSim.Region.Physics.Manager;
using OpenMetaverse;

//using OpenSim.Region.Physics.OdePlugin.Meshing;

namespace OpenSim.Region.Physics.OdePlugin
{
    /// <summary>
    /// ODE plugin
    /// </summary>
    public class OdePlugin : IPhysicsPlugin
    {
        //private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        private CollisionLocker ode;
        private OdeScene _mScene;

        public OdePlugin()
        {
            ode = new CollisionLocker();
        }

        public bool Init()
        {
            return true;
        }

        public PhysicsScene GetScene(String sceneIdentifier)
        {
            if (_mScene == null)
            {
                // Initializing ODE only when a scene is created allows alternative ODE plugins to co-habit (according to
                // http://opensimulator.org/mantis/view.php?id=2750).
                d.InitODE();
                
                _mScene = new OdeScene(ode, sceneIdentifier);
            }
            return (_mScene);
        }

        public string GetName()
        {
            return ("OpenDynamicsEngine");
        }

        public void Dispose()
        {
        }
    }

    public enum StatusIndicators : int
    {
        Generic = 0,
        Start = 1,
        End = 2
    }

    public struct sCollisionData
    {
        public uint ColliderLocalId;
        public uint CollidedWithLocalId;
        public int NumberOfCollisions;
        public int CollisionType;
        public int StatusIndicator;
        public int lastframe;
    }

    [Flags]
    public enum CollisionCategories : int
    {
        Disabled = 0,
        Geom = 0x00000001,
        Body = 0x00000002,
        Space = 0x00000004,
        Character = 0x00000008,
        Land = 0x00000010,
        Water = 0x00000020,
        Wind = 0x00000040,
        Sensor = 0x00000080,
        Selected = 0x00000100
    }

    public sealed class OdeScene : PhysicsScene
    {
        private readonly ILog m_log;
        // private Dictionary<string, sCollisionData> m_storedCollisions = new Dictionary<string, sCollisionData>();

        CollisionLocker ode;

        private Random fluidRandomizer = new Random(Environment.TickCount);

        private const uint m_regionWidth = Constants.RegionSize;
        private const uint m_regionHeight = Constants.RegionSize;

        private float ODE_STEPSIZE = 0.020f;
        private float metersInSpace = 29.9f;

        public float gravityx = 0f;
        public float gravityy = 0f;
        public float gravityz = -9.8f;

        private float contactsurfacelayer = 0.001f;

        private int worldHashspaceLow = -4;
        private int worldHashspaceHigh = 128;

        private int smallHashspaceLow = -4;
        private int smallHashspaceHigh = 66;

        private float waterlevel = 0f;
        private int framecount = 0;
        //private int m_returncollisions = 10;

        private readonly IntPtr contactgroup;
        private IntPtr LandGeom;

        private IntPtr WaterGeom;

        private float nmTerrainContactFriction = 255.0f;
        private float nmTerrainContactBounce = 0.1f;
        private float nmTerrainContactERP = 0.1025f;

        private float mTerrainContactFriction = 75f;
        private float mTerrainContactBounce = 0.1f;
        private float mTerrainContactERP = 0.05025f;

        private float nmAvatarObjectContactFriction = 250f;
        private float nmAvatarObjectContactBounce = 0.1f;

        private float mAvatarObjectContactFriction = 75f;
        private float mAvatarObjectContactBounce = 0.1f;

        private float avPIDD = 3200f;
        private float avPIDP = 1400f;
        private float avCapRadius = 0.37f;
        private float avStandupTensor = 2000000f;
        private float avDensity = 80f;
        private float avHeightFudgeFactor = 0.52f;
        private float avMovementDivisorWalk = 1.3f;
        private float avMovementDivisorRun = 0.8f;
        private float minimumGroundFlightOffset = 3f;

        public bool meshSculptedPrim = true;

        public float meshSculptLOD = 32;
        public float MeshSculptphysicalLOD = 16;

        public float geomDefaultDensity = 10.000006836f;

        public int geomContactPointsStartthrottle = 3;
        public int geomUpdatesPerThrottledUpdate = 15;

        public float bodyPIDD = 35f;
        public float bodyPIDG = 25;

        public int geomCrossingFailuresBeforeOutofbounds = 5;

        public float bodyMotorJointMaxforceTensor = 2;

        public int bodyFramesAutoDisable = 20;

        private float[] _heightmap;

        private float[] _watermap;
        private bool m_filterCollisions = true;

        private float[] _origheightmap;    // Used for Fly height. Kitto Flora

        private d.NearCallback nearCallback;
        public d.TriCallback triCallback;
        public d.TriArrayCallback triArrayCallback;
        private readonly List<OdeCharacter> _characters = new List<OdeCharacter>();
        private readonly List<OdePrim> _prims = new List<OdePrim>();
        private readonly List<OdePrim> _activeprims = new List<OdePrim>();
        private readonly List<OdePrim> _taintedPrim = new List<OdePrim>();
        private readonly List<OdeCharacter> _taintedActors = new List<OdeCharacter>();
        private readonly List<d.ContactGeom> _perloopContact = new List<d.ContactGeom>();
        private readonly List<PhysicsActor> _collisionEventPrim = new List<PhysicsActor>();
        public Dictionary<IntPtr, String> geom_name_map = new Dictionary<IntPtr, String>();
        public Dictionary<IntPtr, PhysicsActor> actor_name_map = new Dictionary<IntPtr, PhysicsActor>();
        private bool m_NINJA_physics_joints_enabled = false;
        //private Dictionary<String, IntPtr> jointpart_name_map = new Dictionary<String,IntPtr>();
        private readonly Dictionary<String, List<PhysicsJoint>> joints_connecting_actor = new Dictionary<String, List<PhysicsJoint>>();
        private d.ContactGeom[] contacts = new d.ContactGeom[80];
        private readonly List<PhysicsJoint> requestedJointsToBeCreated = new List<PhysicsJoint>(); // lock only briefly. accessed by external code (to request new joints) and by OdeScene.Simulate() to move those joints into pending/active
        private readonly List<PhysicsJoint> pendingJoints = new List<PhysicsJoint>(); // can lock for longer. accessed only by OdeScene.
        private readonly List<PhysicsJoint> activeJoints = new List<PhysicsJoint>(); // can lock for longer. accessed only by OdeScene.
        private readonly List<string> requestedJointsToBeDeleted = new List<string>(); // lock only briefly. accessed by external code (to request deletion of joints) and by OdeScene.Simulate() to move those joints out of pending/active
        private Object externalJointRequestsLock = new Object();
        private readonly Dictionary<String, PhysicsJoint> SOPName_to_activeJoint = new Dictionary<String, PhysicsJoint>();
        private readonly Dictionary<String, PhysicsJoint> SOPName_to_pendingJoint = new Dictionary<String, PhysicsJoint>();

        private d.Contact contact;
        private d.Contact TerrainContact;
        private d.Contact AvatarMovementprimContact;
        private d.Contact AvatarMovementTerrainContact;
        private d.Contact WaterContact;

//Ckrinke: Comment out until used. We declare it, initialize it, but do not use it
//Ckrinke        private int m_randomizeWater = 200;
        private int m_physicsiterations = 10;
        private const float m_SkipFramesAtms = 0.40f; // Drop frames gracefully at a 400 ms lag
        private readonly PhysicsActor PANull = new NullPhysicsActor();
        private float step_time = 0.0f;
//Ckrinke: Comment out until used. We declare it, initialize it, but do not use it
//Ckrinke        private int ms = 0;
        public IntPtr world;
        //private bool returncollisions = false;
        // private uint obj1LocalID = 0;
        private uint obj2LocalID = 0;
        //private int ctype = 0;
        private OdeCharacter cc1;
        private OdePrim cp1;
        private OdeCharacter cc2;
        private OdePrim cp2;
        //private int cStartStop = 0;
        //private string cDictKey = "";

        public IntPtr space;

        //private IntPtr tmpSpace;
        // split static geometry collision handling into spaces of 30 meters
        public IntPtr[,] staticPrimspace;

        public Object OdeLock;

        public IMesher mesher;

        private IConfigSource m_config;

        public bool physics_logging = false;
        public int physics_logging_interval = 0;
        public bool physics_logging_append_existing_logfile = false;

        public d.Vector3 xyz = new d.Vector3(128.1640f, 128.3079f, 25.7600f);
        public d.Vector3 hpr = new d.Vector3(125.5000f, -17.0000f, 0.0000f);

        private volatile int m_global_contactcount = 0;

        /// <summary>
        /// Initiailizes the scene
        /// Sets many properties that ODE requires to be stable
        /// These settings need to be tweaked 'exactly' right or weird stuff happens.
        /// </summary>
        public OdeScene(CollisionLocker dode, string sceneIdentifier)
        {
            m_log 
                = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType.ToString() + "." + sceneIdentifier);

            OdeLock = new Object();
            ode = dode;
            nearCallback = near;
            triCallback = TriCallback;
            triArrayCallback = TriArrayCallback;

            lock (OdeLock)
            {
                // Create the world and the first space
                world = d.WorldCreate();
                space = d.HashSpaceCreate(IntPtr.Zero);
                

                contactgroup = d.JointGroupCreate(0);
                //contactgroup

                d.WorldSetAutoDisableFlag(world, false);
                #if USE_DRAWSTUFF
                
                Thread viewthread = new Thread(new ParameterizedThreadStart(startvisualization));
                viewthread.Start();
                #endif
            }

            // zero out a heightmap array float array (single dimention [flattened]))
            _heightmap = new float[514*514];
            _watermap = new float[258 * 258];

            // Zero out the prim spaces array (we split our space into smaller spaces so
            // we can hit test less.
        }

#if USE_DRAWSTUFF
        public void startvisualization(object o)
        {
            ds.Functions fn;
            fn.version = ds.VERSION;
            fn.start = new ds.CallbackFunction(start);
            fn.step = new ds.CallbackFunction(step);
            fn.command = new ds.CallbackFunction(command);
            fn.stop = null;
            fn.path_to_textures = "./textures";
            string[] args = new string[0];
            ds.SimulationLoop(args.Length, args, 352, 288, ref fn);
        }
#endif

        // Initialize the mesh plugin
        public override void Initialise(IMesher meshmerizer, IConfigSource config)
        {
            mesher = meshmerizer;
            m_config = config;
            // Defaults

            if (Environment.OSVersion.Platform == PlatformID.Unix)
            {
                avPIDD = 3200.0f;
                avPIDP = 1400.0f;
                avStandupTensor = 2000000f;
            }
            else
            {
                avPIDD = 2200.0f;
                avPIDP = 900.0f;
                avStandupTensor = 550000f;
            }

            if (m_config != null)
            {
                IConfig physicsconfig = m_config.Configs["ODEPhysicsSettings"];
                if (physicsconfig != null)
                {
                    gravityx = physicsconfig.GetFloat("world_gravityx", 0f);
                    gravityy = physicsconfig.GetFloat("world_gravityy", 0f);
                    gravityz = physicsconfig.GetFloat("world_gravityz", -9.8f);

                    worldHashspaceLow = physicsconfig.GetInt("world_hashspace_low", -4);
                    worldHashspaceHigh = physicsconfig.GetInt("world_hashspace_high", 128);

                    metersInSpace = physicsconfig.GetFloat("meters_in_small_space", 29.9f);
                    smallHashspaceLow = physicsconfig.GetInt("small_hashspace_size_low", -4);
                    smallHashspaceHigh = physicsconfig.GetInt("small_hashspace_size_high", 66);

                    contactsurfacelayer = physicsconfig.GetFloat("world_contact_surface_layer", 0.001f);

                    nmTerrainContactFriction = physicsconfig.GetFloat("nm_terraincontact_friction", 255.0f);
                    nmTerrainContactBounce = physicsconfig.GetFloat("nm_terraincontact_bounce", 0.1f);
                    nmTerrainContactERP = physicsconfig.GetFloat("nm_terraincontact_erp", 0.1025f);

                    mTerrainContactFriction = physicsconfig.GetFloat("m_terraincontact_friction", 75f);
                    mTerrainContactBounce = physicsconfig.GetFloat("m_terraincontact_bounce", 0.1f);
                    mTerrainContactERP = physicsconfig.GetFloat("m_terraincontact_erp", 0.05025f);

                    nmAvatarObjectContactFriction = physicsconfig.GetFloat("objectcontact_friction", 250f);
                    nmAvatarObjectContactBounce = physicsconfig.GetFloat("objectcontact_bounce", 0.2f);

                    mAvatarObjectContactFriction = physicsconfig.GetFloat("m_avatarobjectcontact_friction", 75f);
                    mAvatarObjectContactBounce = physicsconfig.GetFloat("m_avatarobjectcontact_bounce", 0.1f);

                    ODE_STEPSIZE = physicsconfig.GetFloat("world_stepsize", 0.020f);
                    m_physicsiterations = physicsconfig.GetInt("world_internal_steps_without_collisions", 10);

                    avDensity = physicsconfig.GetFloat("av_density", 80f);
                    avHeightFudgeFactor = physicsconfig.GetFloat("av_height_fudge_factor", 0.52f);
                    avMovementDivisorWalk = physicsconfig.GetFloat("av_movement_divisor_walk", 1.3f);
                    avMovementDivisorRun = physicsconfig.GetFloat("av_movement_divisor_run", 0.8f);
                    avCapRadius = physicsconfig.GetFloat("av_capsule_radius", 0.37f);

                    geomContactPointsStartthrottle = physicsconfig.GetInt("geom_contactpoints_start_throttling", 3);
                    geomUpdatesPerThrottledUpdate = physicsconfig.GetInt("geom_updates_before_throttled_update", 15);
                    geomCrossingFailuresBeforeOutofbounds = physicsconfig.GetInt("geom_crossing_failures_before_outofbounds", 5);

                    geomDefaultDensity = physicsconfig.GetFloat("geometry_default_density", 10.000006836f);
                    bodyFramesAutoDisable = physicsconfig.GetInt("body_frames_auto_disable", 20);

                    bodyPIDD = physicsconfig.GetFloat("body_pid_derivative", 35f);
                    bodyPIDG = physicsconfig.GetFloat("body_pid_gain", 25f);

                    meshSculptedPrim = physicsconfig.GetBoolean("mesh_sculpted_prim", true);
                    meshSculptLOD = physicsconfig.GetFloat("mesh_lod", 32f);
                    MeshSculptphysicalLOD = physicsconfig.GetFloat("mesh_physical_lod", 16f);
                    m_filterCollisions = physicsconfig.GetBoolean("filter_collisions", true);

                    if (Environment.OSVersion.Platform == PlatformID.Unix)
                    {
                        avPIDD = physicsconfig.GetFloat("av_pid_derivative_linux", 2200.0f);
                        avPIDP = physicsconfig.GetFloat("av_pid_proportional_linux", 900.0f);
                        avStandupTensor = physicsconfig.GetFloat("av_capsule_standup_tensor_linux", 550000f);
                        bodyMotorJointMaxforceTensor = physicsconfig.GetFloat("body_motor_joint_maxforce_tensor_linux", 5f);
                    }
                    else
                    {
                        avPIDD = physicsconfig.GetFloat("av_pid_derivative_win", 2200.0f);
                        avPIDP = physicsconfig.GetFloat("av_pid_proportional_win", 900.0f);
                        avStandupTensor = physicsconfig.GetFloat("av_capsule_standup_tensor_win", 550000f);
                        bodyMotorJointMaxforceTensor = physicsconfig.GetFloat("body_motor_joint_maxforce_tensor_win", 5f);
                    }

                    physics_logging = physicsconfig.GetBoolean("physics_logging", false);
                    physics_logging_interval = physicsconfig.GetInt("physics_logging_interval", 0);
                    physics_logging_append_existing_logfile = physicsconfig.GetBoolean("physics_logging_append_existing_logfile", false);

                    m_NINJA_physics_joints_enabled = physicsconfig.GetBoolean("use_NINJA_physics_joints", false);
                    minimumGroundFlightOffset = physicsconfig.GetFloat("minimum_ground_flight_offset", 3f);

                }
            }

            staticPrimspace = new IntPtr[(int)(300 / metersInSpace), (int)(300 / metersInSpace)];

            // Centeral contact friction and bounce
            // ckrinke 11/10/08 Enabling soft_erp but not soft_cfm until I figure out why
            // an avatar falls through in Z but not in X or Y when walking on a prim.
            contact.surface.mode |= d.ContactFlags.SoftERP;
            contact.surface.mu = nmAvatarObjectContactFriction;
            contact.surface.bounce = nmAvatarObjectContactBounce;
            contact.surface.soft_cfm = 0.010f;
            contact.surface.soft_erp = 0.010f;

            // Terrain contact friction and Bounce
            // This is the *non* moving version.   Use this when an avatar
            // isn't moving to keep it in place better
            TerrainContact.surface.mode |= d.ContactFlags.SoftERP;
            TerrainContact.surface.mu = nmTerrainContactFriction;
            TerrainContact.surface.bounce = nmTerrainContactBounce;
            TerrainContact.surface.soft_erp = nmTerrainContactERP;

            WaterContact.surface.mode |= (d.ContactFlags.SoftERP | d.ContactFlags.SoftCFM);
            WaterContact.surface.mu = 0f; // No friction
            WaterContact.surface.bounce = 0.0f; // No bounce
            WaterContact.surface.soft_cfm = 0.010f;
            WaterContact.surface.soft_erp = 0.010f;

            // Prim contact friction and bounce
            // THis is the *non* moving version of friction and bounce
            // Use this when an avatar comes in contact with a prim
            // and is moving
            AvatarMovementprimContact.surface.mu = mAvatarObjectContactFriction;
            AvatarMovementprimContact.surface.bounce = mAvatarObjectContactBounce;

            // Terrain contact friction bounce and various error correcting calculations
            // Use this when an avatar is in contact with the terrain and moving.
            AvatarMovementTerrainContact.surface.mode |= d.ContactFlags.SoftERP;
            AvatarMovementTerrainContact.surface.mu = mTerrainContactFriction;
            AvatarMovementTerrainContact.surface.bounce = mTerrainContactBounce;
            AvatarMovementTerrainContact.surface.soft_erp = mTerrainContactERP;

            d.HashSpaceSetLevels(space, worldHashspaceLow, worldHashspaceHigh);

            // Set the gravity,, don't disable things automatically (we set it explicitly on some things)

            d.WorldSetGravity(world, gravityx, gravityy, gravityz);
            d.WorldSetContactSurfaceLayer(world, contactsurfacelayer);

            d.WorldSetLinearDamping(world, 256f);
            d.WorldSetAngularDamping(world, 256f);
            d.WorldSetAngularDampingThreshold(world, 256f);
            d.WorldSetLinearDampingThreshold(world, 256f);
            d.WorldSetMaxAngularSpeed(world, 256f);

            // Set how many steps we go without running collision testing
            // This is in addition to the step size.
            // Essentially Steps * m_physicsiterations
            d.WorldSetQuickStepNumIterations(world, m_physicsiterations);
            //d.WorldSetContactMaxCorrectingVel(world, 1000.0f);

            

            for (int i = 0; i < staticPrimspace.GetLength(0); i++)
            {
                for (int j = 0; j < staticPrimspace.GetLength(1); j++)
                {
                    staticPrimspace[i, j] = IntPtr.Zero;
                }
            }
        }

        internal void waitForSpaceUnlock(IntPtr space)
        {
            //if (space != IntPtr.Zero)
                //while (d.SpaceLockQuery(space)) { } // Wait and do nothing
        }

        /// <summary>
        /// Debug space message for printing the space that a prim/avatar is in.
        /// </summary>
        /// <param name="pos"></param>
        /// <returns>Returns which split up space the given position is in.</returns>
        public string whichspaceamIin(PhysicsVector pos)
        {
            return calculateSpaceForGeom(pos).ToString();
        }

        #region Collision Detection

        /// <summary>
        /// This is our near callback.  A geometry is near a body
        /// </summary>
        /// <param name="space">The space that contains the geoms.  Remember, spaces are also geoms</param>
        /// <param name="g1">a geometry or space</param>
        /// <param name="g2">another geometry or space</param>
        private void near(IntPtr space, IntPtr g1, IntPtr g2)
        {
            //  no lock here!  It's invoked from within Simulate(), which is thread-locked

            // Test if we're colliding a geom with a space.
            // If so we have to drill down into the space recursively

            if (d.GeomIsSpace(g1) || d.GeomIsSpace(g2))
            {
                if (g1 == IntPtr.Zero || g2 == IntPtr.Zero)
                    return;
                
                // Separating static prim geometry spaces.
                // We'll be calling near recursivly if one
                // of them is a space to find all of the
                // contact points in the space
                try
                {
                    d.SpaceCollide2(g1, g2, IntPtr.Zero, nearCallback);
                }
                catch (AccessViolationException)
                {
                    m_log.Warn("[PHYSICS]: Unable to collide test a space");
                    return;
                }
                //Colliding a space or a geom with a space or a geom. so drill down

                //Collide all geoms in each space..
                //if (d.GeomIsSpace(g1)) d.SpaceCollide(g1, IntPtr.Zero, nearCallback);
                //if (d.GeomIsSpace(g2)) d.SpaceCollide(g2, IntPtr.Zero, nearCallback);
                return;
            }

            if (g1 == IntPtr.Zero || g2 == IntPtr.Zero)
                return;

            IntPtr b1 = d.GeomGetBody(g1);
            IntPtr b2 = d.GeomGetBody(g2);

            // d.GeomClassID id = d.GeomGetClass(g1);

            String name1 = null;
            String name2 = null;

            if (!geom_name_map.TryGetValue(g1, out name1))
            {
                name1 = "null";
            }
            if (!geom_name_map.TryGetValue(g2, out name2))
            {
                name2 = "null";
            }

            //if (id == d.GeomClassId.TriMeshClass)
            //{
                //               m_log.InfoFormat("near: A collision was detected between {1} and {2}", 0, name1, name2);
                //m_log.Debug("near: A collision was detected between {1} and {2}", 0, name1, name2);
            //}

            // Figure out how many contact points we have
            int count = 0;
            try
            {
                // Colliding Geom To Geom
                // This portion of the function 'was' blatantly ripped off from BoxStack.cs

                if (g1 == g2)
                    return; // Can't collide with yourself

                if (b1 != IntPtr.Zero && b2 != IntPtr.Zero && d.AreConnectedExcluding(b1, b2, d.JointType.Contact))
                    return;

                lock (contacts)
                {
                    count = d.Collide(g1, g2, contacts.GetLength(0), contacts, d.ContactGeom.SizeOf);
                }
            }
            catch (SEHException)
            {
                m_log.Error("[PHYSICS]: The Operating system shut down ODE because of corrupt memory.  This could be a result of really irregular terrain.  If this repeats continuously, restart using Basic Physics and terrain fill your terrain.  Restarting the sim.");
                ode.drelease(world);
                base.TriggerPhysicsBasedRestart();
            }
            catch (AccessViolationException)
            {
                m_log.Warn("[PHYSICS]: Unable to collide test an object");
                return;
            }

            PhysicsActor p1;
            PhysicsActor p2;

            if (!actor_name_map.TryGetValue(g1, out p1))
            {
                p1 = PANull;
            }

            if (!actor_name_map.TryGetValue(g2, out p2))
            {
                p2 = PANull;
            }

            float max_collision_depth = 0f;
            if (p1.CollisionScore + count >= float.MaxValue)
                p1.CollisionScore = 0;
            p1.CollisionScore += count;

            if (p2.CollisionScore + count >= float.MaxValue)
                p2.CollisionScore = 0;
            p2.CollisionScore += count;

            for (int i = 0; i < count; i++)
            {


                max_collision_depth = (contacts[i].depth > max_collision_depth) ? contacts[i].depth : max_collision_depth;
                //m_log.Warn("[CCOUNT]: " + count);
                IntPtr joint;
                // If we're colliding with terrain, use 'TerrainContact' instead of contact.
                // allows us to have different settings
                
                // We only need to test p2 for 'jump crouch purposes'
                p2.IsColliding = true;
                
                //if ((framecount % m_returncollisions) == 0)

                switch (p1.PhysicsActorType)
                {
                    case (int)ActorTypes.Agent:
                        p2.CollidingObj = true;
                        break;
                    case (int)ActorTypes.Prim:
                        if (p2.Velocity.X > 0 || p2.Velocity.Y > 0 || p2.Velocity.Z > 0)
                            p2.CollidingObj = true;
                        break;
                    case (int)ActorTypes.Unknown:
                        p2.CollidingGround = true;
                        break;
                    default:
                        p2.CollidingGround = true;
                        break;
                }

                // we don't want prim or avatar to explode

                #region InterPenetration Handling - Unintended physics explosions

                if (contacts[i].depth >= 0.08f)
                {
                    //This is disabled at the moment only because it needs more tweaking
                    //It will eventually be uncommented

                    if (contacts[i].depth >= 1.00f)
                    {
                        //m_log.Debug("[PHYSICS]: " + contacts[i].depth.ToString());
                    }

                    //If you interpenetrate a prim with an agent
                    if ((p2.PhysicsActorType == (int) ActorTypes.Agent &&
                         p1.PhysicsActorType == (int) ActorTypes.Prim) ||
                        (p1.PhysicsActorType == (int) ActorTypes.Agent &&
                         p2.PhysicsActorType == (int) ActorTypes.Prim))
                    {
                        # region disabled code1
                        //contacts[i].depth = contacts[i].depth * 4.15f;
                        /*
                        if (p2.PhysicsActorType == (int) ActorTypes.Agent)
                        {
                            p2.CollidingObj = true;
                            contacts[i].depth = 0.003f;
                            p2.Velocity = p2.Velocity + new PhysicsVector(0, 0, 2.5f);
                            OdeCharacter character = (OdeCharacter) p2;
                            character.SetPidStatus(true);
                            contacts[i].pos = new d.Vector3(contacts[i].pos.X + (p1.Size.X / 2), contacts[i].pos.Y + (p1.Size.Y / 2), contacts[i].pos.Z + (p1.Size.Z / 2));

                        }
                        else
                        {

                            //contacts[i].depth = 0.0000000f;
                        }
                        if (p1.PhysicsActorType == (int) ActorTypes.Agent)
                        {

                            p1.CollidingObj = true;
                            contacts[i].depth = 0.003f;
                            p1.Velocity = p1.Velocity + new PhysicsVector(0, 0, 2.5f);
                            contacts[i].pos = new d.Vector3(contacts[i].pos.X + (p2.Size.X / 2), contacts[i].pos.Y + (p2.Size.Y / 2), contacts[i].pos.Z + (p2.Size.Z / 2));
                            OdeCharacter character = (OdeCharacter)p1;
                            character.SetPidStatus(true);
                        }
                        else
                        {

                            //contacts[i].depth = 0.0000000f;
                        }
                          */
                        #endregion
                    }

                    // If you interpenetrate a prim with another prim
                    if (p1.PhysicsActorType == (int) ActorTypes.Prim && p2.PhysicsActorType == (int) ActorTypes.Prim)
                    {
                        #region disabledcode2
                        //OdePrim op1 = (OdePrim)p1;
                        //OdePrim op2 = (OdePrim)p2;
                        //op1.m_collisionscore++;
                        //op2.m_collisionscore++;

                        //if (op1.m_collisionscore > 8000 || op2.m_collisionscore > 8000)
                        //{
                            //op1.m_taintdisable = true;
                            //AddPhysicsActorTaint(p1);
                            //op2.m_taintdisable = true;
                            //AddPhysicsActorTaint(p2);
                        //}

                        //if (contacts[i].depth >= 0.25f)
                        //{
                            // Don't collide, one or both prim will expld.

                            //op1.m_interpenetrationcount++;
                            //op2.m_interpenetrationcount++;
                            //interpenetrations_before_disable = 200;
                            //if (op1.m_interpenetrationcount >= interpenetrations_before_disable)
                            //{
                                //op1.m_taintdisable = true;
                                //AddPhysicsActorTaint(p1);
                            //}
                            //if (op2.m_interpenetrationcount >= interpenetrations_before_disable)
                            //{
                               // op2.m_taintdisable = true;
                                //AddPhysicsActorTaint(p2);
                            //}

                            //contacts[i].depth = contacts[i].depth / 8f;
                            //contacts[i].normal = new d.Vector3(0, 0, 1);
                        //}
                        //if (op1.m_disabled || op2.m_disabled)
                        //{
                            //Manually disabled objects stay disabled
                            //contacts[i].depth = 0f;
                        //}
                        #endregion
                    }

                    if (contacts[i].depth >= 1.00f)
                    {
                        //m_log.Info("[P]: " + contacts[i].depth.ToString());
                        if ((p2.PhysicsActorType == (int) ActorTypes.Agent &&
                             p1.PhysicsActorType == (int) ActorTypes.Unknown) ||
                            (p1.PhysicsActorType == (int) ActorTypes.Agent &&
                             p2.PhysicsActorType == (int) ActorTypes.Unknown))
                        {
                            if (p2.PhysicsActorType == (int) ActorTypes.Agent)
                            {
                                OdeCharacter character = (OdeCharacter) p2;

                                //p2.CollidingObj = true;
                                contacts[i].depth = 0.00000003f;
                                p2.Velocity = p2.Velocity + new PhysicsVector(0, 0, 0.5f);
                                contacts[i].pos =
                                    new d.Vector3(contacts[i].pos.X + (p1.Size.X/2),
                                                  contacts[i].pos.Y + (p1.Size.Y/2),
                                                  contacts[i].pos.Z + (p1.Size.Z/2));
                                character.SetPidStatus(true);
                            }
                            else
                            {
                            }

                            if (p1.PhysicsActorType == (int) ActorTypes.Agent)
                            {
                                OdeCharacter character = (OdeCharacter)p1;

                                //p2.CollidingObj = true;
                                contacts[i].depth = 0.00000003f;
                                p1.Velocity = p1.Velocity + new PhysicsVector(0, 0, 0.5f);
                                contacts[i].pos =
                                    new d.Vector3(contacts[i].pos.X + (p1.Size.X/2),
                                                  contacts[i].pos.Y + (p1.Size.Y/2),
                                                  contacts[i].pos.Z + (p1.Size.Z/2));
                                character.SetPidStatus(true);
                            }
                            else
                            {
                                //contacts[i].depth = 0.0000000f;
                            }
                        }
                    }
                }

                #endregion

                // Logic for collision handling
                // Note, that if *all* contacts are skipped (VolumeDetect)
                // The prim still detects (and forwards) collision events but 
                // appears to be phantom for the world
                Boolean skipThisContact = false;

                if ((p1 is OdePrim) && (((OdePrim)p1).m_isVolumeDetect))
                    skipThisContact = true;   // No collision on volume detect prims

                if (!skipThisContact && (p2 is OdePrim) && (((OdePrim)p2).m_isVolumeDetect))
                    skipThisContact = true;   // No collision on volume detect prims

                if (!skipThisContact && contacts[i].depth < 0f)
                    skipThisContact = true;

                if (!skipThisContact && checkDupe(contacts[i], p2.PhysicsActorType))
                    skipThisContact = true;

                int maxContactsbeforedeath = 4000;
                joint = IntPtr.Zero;


                if (!skipThisContact)
                {
                    // If we're colliding against terrain
                    if (name1 == "Terrain" || name2 == "Terrain")
                    {
                        // If we're moving
                        if ((p2.PhysicsActorType == (int) ActorTypes.Agent) &&
                            (Math.Abs(p2.Velocity.X) > 0.01f || Math.Abs(p2.Velocity.Y) > 0.01f))
                        {
                            // Use the movement terrain contact
                            AvatarMovementTerrainContact.geom = contacts[i];
                            _perloopContact.Add(contacts[i]);
                            if (m_global_contactcount < maxContactsbeforedeath)
                            {
                                joint = d.JointCreateContact(world, contactgroup, ref AvatarMovementTerrainContact);
                                m_global_contactcount++;
                            }
                        }
                        else
                        {
                            // Use the non moving terrain contact
                            TerrainContact.geom = contacts[i];
                            _perloopContact.Add(contacts[i]);
                            if (m_global_contactcount < maxContactsbeforedeath)
                            {
                                joint = d.JointCreateContact(world, contactgroup, ref TerrainContact);
                                m_global_contactcount++;
                            }
                        }
                        //if (p2.PhysicsActorType == (int)ActorTypes.Prim)
                        //{
                        //m_log.Debug("[PHYSICS]: prim contacting with ground");
                        //}
                    }
                    else if (name1 == "Water" || name2 == "Water")
                    {
                        if ((p2.PhysicsActorType == (int) ActorTypes.Prim))
                        {
                        }
                        else
                        {
                        }

                        //WaterContact.surface.soft_cfm = 0.0000f;
                        //WaterContact.surface.soft_erp = 0.00000f;
                        if (contacts[i].depth > 0.1f)
                        {
                            contacts[i].depth *= 52;
                            //contacts[i].normal = new d.Vector3(0, 0, 1);
                            //contacts[i].pos = new d.Vector3(0, 0, contacts[i].pos.Z - 5f);
                        }
                        WaterContact.geom = contacts[i];
                        _perloopContact.Add(contacts[i]);
                        if (m_global_contactcount < maxContactsbeforedeath)
                        {
                            joint = d.JointCreateContact(world, contactgroup, ref WaterContact);
                            m_global_contactcount++;
                        }
                        //m_log.Info("[PHYSICS]: Prim Water Contact" + contacts[i].depth);
                    }
                    else
                    {
                        // we're colliding with prim or avatar
                        // check if we're moving
                        if ((p2.PhysicsActorType == (int) ActorTypes.Agent) &&
                            (Math.Abs(p2.Velocity.X) > 0.01f || Math.Abs(p2.Velocity.Y) > 0.01f))
                        {
                            // Use the Movement prim contact
                            AvatarMovementprimContact.geom = contacts[i];
                            _perloopContact.Add(contacts[i]);
                            if (m_global_contactcount < maxContactsbeforedeath)
                            {
                                joint = d.JointCreateContact(world, contactgroup, ref AvatarMovementprimContact);
                                m_global_contactcount++;
                            }
                        }
                        else
                        {
                            // Use the non movement contact
                            contact.geom = contacts[i];
                            _perloopContact.Add(contacts[i]);

                            if (m_global_contactcount < maxContactsbeforedeath)
                            {
                                joint = d.JointCreateContact(world, contactgroup, ref contact);
                                m_global_contactcount++;
                            }
                        }
                    }

                    if (m_global_contactcount < maxContactsbeforedeath && joint != IntPtr.Zero) // stack collide!
                    {
                        d.JointAttach(joint, b1, b2);
                        m_global_contactcount++;
                    }

                }
                collision_accounting_events(p1, p2, max_collision_depth);
                if (count > geomContactPointsStartthrottle)
                {
                    // If there are more then 3 contact points, it's likely
                    // that we've got a pile of objects, so ...
                    // We don't want to send out hundreds of terse updates over and over again
                    // so lets throttle them and send them again after it's somewhat sorted out.
                    p2.ThrottleUpdates = true;
                }
                //m_log.Debug(count.ToString());
                //m_log.Debug("near: A collision was detected between {1} and {2}", 0, name1, name2);
            }
        }

        private bool checkDupe(d.ContactGeom contactGeom, int atype)
        {
            bool result = false;
            //return result;
            if (!m_filterCollisions)
                return false;

            ActorTypes at = (ActorTypes)atype;
            lock (_perloopContact)
            {
                foreach (d.ContactGeom contact in _perloopContact)
                {
                    //if ((contact.g1 == contactGeom.g1 && contact.g2 == contactGeom.g2))
                    //{
                        // || (contact.g2 == contactGeom.g1 && contact.g1 == contactGeom.g2)
                    if (at == ActorTypes.Agent)
                    {
                            if (((Math.Abs(contactGeom.normal.X - contact.normal.X) < 1.026f) && (Math.Abs(contactGeom.normal.Y - contact.normal.Y) < 0.303f) && (Math.Abs(contactGeom.normal.Z - contact.normal.Z) < 0.065f)) && contactGeom.g1 != LandGeom && contactGeom.g2 != LandGeom)
                            {
                                
                                if (Math.Abs(contact.depth - contactGeom.depth) < 0.052f)
                                {
                                    //contactGeom.depth *= .00005f;
                                   //m_log.DebugFormat("[Collsion]: Depth {0}", Math.Abs(contact.depth - contactGeom.depth));
                                    // m_log.DebugFormat("[Collision]: <{0},{1},{2}>", Math.Abs(contactGeom.normal.X - contact.normal.X), Math.Abs(contactGeom.normal.Y - contact.normal.Y), Math.Abs(contactGeom.normal.Z - contact.normal.Z));
                                    result = true;
                                    break;
                                }
                                else
                                {
                                    //m_log.DebugFormat("[Collsion]: Depth {0}", Math.Abs(contact.depth - contactGeom.depth));
                                }
                            }
                            else
                            {
                                //m_log.DebugFormat("[Collision]: <{0},{1},{2}>", Math.Abs(contactGeom.normal.X - contact.normal.X), Math.Abs(contactGeom.normal.Y - contact.normal.Y), Math.Abs(contactGeom.normal.Z - contact.normal.Z));
                                //int i = 0;
                            }
                    } 
                    else if (at == ActorTypes.Prim)
                    {
                            //d.AABB aabb1 = new d.AABB();
                            //d.AABB aabb2 = new d.AABB();

                            //d.GeomGetAABB(contactGeom.g2, out aabb2);
                            //d.GeomGetAABB(contactGeom.g1, out aabb1);
                            //aabb1.
                            if (((Math.Abs(contactGeom.normal.X - contact.normal.X) < 1.026f) && (Math.Abs(contactGeom.normal.Y - contact.normal.Y) < 0.303f) && (Math.Abs(contactGeom.normal.Z - contact.normal.Z) < 0.065f)) && contactGeom.g1 != LandGeom && contactGeom.g2 != LandGeom)
                            {
                                if (contactGeom.normal.X == contact.normal.X && contactGeom.normal.Y == contact.normal.Y && contactGeom.normal.Z == contact.normal.Z)
                                {
                                    if (Math.Abs(contact.depth - contactGeom.depth) < 0.272f)
                                    {
                                        result = true;
                                        break;
                                    }
                                }
                                //m_log.DebugFormat("[Collsion]: Depth {0}", Math.Abs(contact.depth - contactGeom.depth));
                                //m_log.DebugFormat("[Collision]: <{0},{1},{2}>", Math.Abs(contactGeom.normal.X - contact.normal.X), Math.Abs(contactGeom.normal.Y - contact.normal.Y), Math.Abs(contactGeom.normal.Z - contact.normal.Z));
                            }
                            
                    }
                    
                    //}

                }
            }
            return result;
        }

        private void collision_accounting_events(PhysicsActor p1, PhysicsActor p2, float collisiondepth)
        {
            // obj1LocalID = 0;
            //returncollisions = false;
            obj2LocalID = 0;
            //ctype = 0;
            //cStartStop = 0;
            if (!p2.SubscribedEvents() && !p1.SubscribedEvents())
                return;

            switch ((ActorTypes)p2.PhysicsActorType)
            {
                case ActorTypes.Agent:
                    cc2 = (OdeCharacter)p2;

                    // obj1LocalID = cc2.m_localID;
                    switch ((ActorTypes)p1.PhysicsActorType)
                    {
                        case ActorTypes.Agent:
                            cc1 = (OdeCharacter)p1;
                            obj2LocalID = cc1.m_localID;
                            cc1.AddCollisionEvent(cc2.m_localID, collisiondepth);
                            //ctype = (int)CollisionCategories.Character;

                            //if (cc1.CollidingObj)
                            //cStartStop = (int)StatusIndicators.Generic;
                            //else
                            //cStartStop = (int)StatusIndicators.Start;

                            //returncollisions = true;
                            break;
                        case ActorTypes.Prim:
                            cp1 = (OdePrim)p1;
                            obj2LocalID = cp1.m_localID;
                            cp1.AddCollisionEvent(cc2.m_localID, collisiondepth);
                            //ctype = (int)CollisionCategories.Geom;

                            //if (cp1.CollidingObj)
                            //cStartStop = (int)StatusIndicators.Generic;
                            //else
                            //cStartStop = (int)StatusIndicators.Start;

                            //returncollisions = true;
                            break;

                        case ActorTypes.Ground:
                        case ActorTypes.Unknown:
                            obj2LocalID = 0;
                            //ctype = (int)CollisionCategories.Land;
                            //returncollisions = true;
                            break;
                    }

                    cc2.AddCollisionEvent(obj2LocalID, collisiondepth);
                    break;
                case ActorTypes.Prim:
                    cp2 = (OdePrim)p2;

                    // obj1LocalID = cp2.m_localID;
                    switch ((ActorTypes)p1.PhysicsActorType)
                    {
                        case ActorTypes.Agent:
                            cc1 = (OdeCharacter)p1;
                            obj2LocalID = cc1.m_localID;
                            cc1.AddCollisionEvent(cp2.m_localID, collisiondepth);
                            //ctype = (int)CollisionCategories.Character;

                            //if (cc1.CollidingObj)
                                //cStartStop = (int)StatusIndicators.Generic;
                            //else
                                //cStartStop = (int)StatusIndicators.Start;
                            //returncollisions = true;

                            break;
                        case ActorTypes.Prim:
                            cp1 = (OdePrim)p1;
                            obj2LocalID = cp1.m_localID;
                            cp1.AddCollisionEvent(cp2.m_localID, collisiondepth);
                            //ctype = (int)CollisionCategories.Geom;

                            //if (cp1.CollidingObj)
                                //cStartStop = (int)StatusIndicators.Generic;
                            //else
                                //cStartStop = (int)StatusIndicators.Start;

                            //returncollisions = true;
                            break;

                        case ActorTypes.Ground:
                        case ActorTypes.Unknown:
                            obj2LocalID = 0;
                            //ctype = (int)CollisionCategories.Land;

                            //returncollisions = true;
                            break;
                    }

                    cp2.AddCollisionEvent(obj2LocalID, collisiondepth);
                    break;
            }
            //if (returncollisions)
            //{

                //lock (m_storedCollisions)
                //{
                    //cDictKey = obj1LocalID.ToString() + obj2LocalID.ToString() + cStartStop.ToString() + ctype.ToString();
                    //if (m_storedCollisions.ContainsKey(cDictKey))
                    //{
                        //sCollisionData objd = m_storedCollisions[cDictKey];
                        //objd.NumberOfCollisions += 1;
                        //objd.lastframe = framecount;
                        //m_storedCollisions[cDictKey] = objd;
                    //}
                    //else
                    //{
                        //sCollisionData objd = new sCollisionData();
                        //objd.ColliderLocalId = obj1LocalID;
                        //objd.CollidedWithLocalId = obj2LocalID;
                        //objd.CollisionType = ctype;
                        //objd.NumberOfCollisions = 1;
                        //objd.lastframe = framecount;
                        //objd.StatusIndicator = cStartStop;
                        //m_storedCollisions.Add(cDictKey, objd);
                    //}
                //}
           // }
        }

        public int TriArrayCallback(IntPtr trimesh, IntPtr refObject, int[] triangleIndex, int triCount)
        {
            /*            String name1 = null;
                        String name2 = null;

                        if (!geom_name_map.TryGetValue(trimesh, out name1))
                        {
                            name1 = "null";
                        }
                        if (!geom_name_map.TryGetValue(refObject, out name2))
                        {
                            name2 = "null";
                        }

                        m_log.InfoFormat("TriArrayCallback: A collision was detected between {1} and {2}", 0, name1, name2);
            */
            return 1;
        }

        public int TriCallback(IntPtr trimesh, IntPtr refObject, int triangleIndex)
        {
            String name1 = null;
            String name2 = null;

            if (!geom_name_map.TryGetValue(trimesh, out name1))
            {
                name1 = "null";
            }

            if (!geom_name_map.TryGetValue(refObject, out name2))
            {
                name2 = "null";
            }

            //            m_log.InfoFormat("TriCallback: A collision was detected between {1} and {2}. Index was {3}", 0, name1, name2, triangleIndex);

            d.Vector3 v0 = new d.Vector3();
            d.Vector3 v1 = new d.Vector3();
            d.Vector3 v2 = new d.Vector3();

            d.GeomTriMeshGetTriangle(trimesh, 0, ref v0, ref v1, ref v2);
            //            m_log.DebugFormat("Triangle {0} is <{1},{2},{3}>, <{4},{5},{6}>, <{7},{8},{9}>", triangleIndex, v0.X, v0.Y, v0.Z, v1.X, v1.Y, v1.Z, v2.X, v2.Y, v2.Z);

            return 1;
        }

        /// <summary>
        /// This is our collision testing routine in ODE
        /// </summary>
        /// <param name="timeStep"></param>
        private void collision_optimized(float timeStep)
        {
            _perloopContact.Clear();

            foreach (OdeCharacter chr in _characters)
            {
                // Reset the collision values to false
                // since we don't know if we're colliding yet

                // For some reason this can happen. Don't ask...
                //
                if (chr == null)
                    continue;

                if (chr.Shell == IntPtr.Zero || chr.Body == IntPtr.Zero)
                    continue;

                chr.IsColliding = false;
                chr.CollidingGround = false;
                chr.CollidingObj = false;

                // test the avatar's geometry for collision with the space
                // This will return near and the space that they are the closest to
                // And we'll run this again against the avatar and the space segment
                // This will return with a bunch of possible objects in the space segment
                // and we'll run it again on all of them.
                try
                {
                    d.SpaceCollide2(space, chr.Shell, IntPtr.Zero, nearCallback);
                }
                catch (AccessViolationException)
                {
                    m_log.Warn("[PHYSICS]: Unable to space collide");
                }
                //float terrainheight = GetTerrainHeightAtXY(chr.Position.X, chr.Position.Y);
                //if (chr.Position.Z + (chr.Velocity.Z * timeStep) < terrainheight + 10)
                //{
                    //chr.Position.Z = terrainheight + 10.0f;
                    //forcedZ = true;
                //}
            }

            lock (_activeprims)
            {
                List<OdePrim> removeprims = null;
                foreach (OdePrim chr in _activeprims)
                {
                    if (chr.Body != IntPtr.Zero && d.BodyIsEnabled(chr.Body) && (!chr.m_disabled))
                    {
                        try
                        {
                            lock (chr)
                            {
                                if (space != IntPtr.Zero && chr.prim_geom != IntPtr.Zero && chr.m_taintremove == false)
                                {
                                    d.SpaceCollide2(space, chr.prim_geom, IntPtr.Zero, nearCallback);
                                }
                                else
                                {
                                    if (removeprims == null)
                                    {
                                        removeprims = new List<OdePrim>();
                                    }
                                    removeprims.Add(chr);
                                    m_log.Debug("[PHYSICS]: unable to collide test active prim against space.  The space was zero, the geom was zero or it was in the process of being removed.  Removed it from the active prim list.  This needs to be fixed!");
                                }
                            }
                        }
                        catch (AccessViolationException)
                        {
                            m_log.Warn("[PHYSICS]: Unable to space collide");
                        }
                    }
                }
                if (removeprims != null)
                {
                    foreach (OdePrim chr in removeprims)
                    {
                        _activeprims.Remove(chr);
                    }
                }
            }

            _perloopContact.Clear();
        }

        #endregion
       
// Recovered for use by fly height. Kitto Flora
        public float GetTerrainHeightAtXY(float x, float y)
        {
            // Teravus: Kitto, this code causes recurring errors that stall physics permenantly unless 
            // the values are checked, so checking below.
            // Is there any reason that we don't do this in ScenePresence?   
            // The only physics engine that benefits from it in the physics plugin is this one

            if ((int)x > Constants.RegionSize || (int)y > Constants.RegionSize || 
                (int)x < 0.001f || (int)y < 0.001f)
                return 0;

            return (float)_origheightmap[(int)y * Constants.RegionSize + (int)x];
        }
// End recovered. Kitto Flora

        public void addCollisionEventReporting(PhysicsActor obj)
        {
            lock (_collisionEventPrim)
            {
                if (!_collisionEventPrim.Contains(obj))
                    _collisionEventPrim.Add(obj);
            }
        }

        public void remCollisionEventReporting(PhysicsActor obj)
        {
            lock (_collisionEventPrim)
            {
                if (!_collisionEventPrim.Contains(obj))
                    _collisionEventPrim.Remove(obj);
            }
        }

        #region Add/Remove Entities

        public override PhysicsActor AddAvatar(string avName, PhysicsVector position, PhysicsVector size, bool isFlying)
        {
            PhysicsVector pos = new PhysicsVector();
            pos.X = position.X;
            pos.Y = position.Y;
            pos.Z = position.Z;
            OdeCharacter newAv = new OdeCharacter(avName, this, pos, ode, size, avPIDD, avPIDP, avCapRadius, avStandupTensor, avDensity, avHeightFudgeFactor, avMovementDivisorWalk, avMovementDivisorRun);
            newAv.Flying = isFlying;
            newAv.MinimumGroundFlightOffset = minimumGroundFlightOffset;
            _characters.Add(newAv);
            return newAv;
        }

        public override void RemoveAvatar(PhysicsActor actor)
        {
            lock (OdeLock)
            {
                //m_log.Debug("[PHYSICS]:ODELOCK");
                ((OdeCharacter) actor).Destroy();
                _characters.Remove((OdeCharacter) actor);
            }
        }

        private PhysicsActor AddPrim(String name, PhysicsVector position, PhysicsVector size, Quaternion rotation,
                                     IMesh mesh, PrimitiveBaseShape pbs, bool isphysical)
        {
            PhysicsVector pos = new PhysicsVector(position.X, position.Y, position.Z);
            //pos.X = position.X;
            //pos.Y = position.Y;
            //pos.Z = position.Z;
            PhysicsVector siz = new PhysicsVector();
            siz.X = size.X;
            siz.Y = size.Y;
            siz.Z = size.Z;
            Quaternion rot = rotation;

            OdePrim newPrim;
            lock (OdeLock)
            {
                newPrim = new OdePrim(name, this, pos, siz, rot, mesh, pbs, isphysical, ode);

                lock (_prims)
                    _prims.Add(newPrim);
            }

            return newPrim;
        }

        public void addActivePrim(OdePrim activatePrim)
        {
            // adds active prim..   (ones that should be iterated over in collisions_optimized
            lock (_activeprims)
            {
                if (!_activeprims.Contains(activatePrim))
                    _activeprims.Add(activatePrim);
                //else
                  //  m_log.Warn("[PHYSICS]: Double Entry in _activeprims detected, potential crash immenent");
            }
        }

        public override PhysicsActor AddPrimShape(string primName, PrimitiveBaseShape pbs, PhysicsVector position,
                                                  PhysicsVector size, Quaternion rotation) //To be removed
        {
            return AddPrimShape(primName, pbs, position, size, rotation, false);
        }

        public override PhysicsActor AddPrimShape(string primName, PrimitiveBaseShape pbs, PhysicsVector position,
                                                  PhysicsVector size, Quaternion rotation, bool isPhysical)
        {
            PhysicsActor result;
            IMesh mesh = null;

            //switch (pbs.ProfileShape)
            //{
            //    case ProfileShape.Square:
            //         //support simple box & hollow box now; later, more shapes
            //        if (needsMeshing(pbs))
            //        {
            //            mesh = mesher.CreateMesh(primName, pbs, size, 32f, isPhysical);
            //        }

            //        break;
            //}

            if (needsMeshing(pbs))
                mesh = mesher.CreateMesh(primName, pbs, size, 32f, isPhysical);

            result = AddPrim(primName, position, size, rotation, mesh, pbs, isPhysical);

            return result;
        }

        public override bool SupportsNINJAJoints
        {
            get { return m_NINJA_physics_joints_enabled; }
        }

        // internal utility function: must be called within a lock (OdeLock)
        private void InternalAddActiveJoint(PhysicsJoint joint)
        {
            activeJoints.Add(joint);
            SOPName_to_activeJoint.Add(joint.ObjectNameInScene, joint);
        }

        // internal utility function: must be called within a lock (OdeLock)
        private void InternalAddPendingJoint(OdePhysicsJoint joint)
        {
            pendingJoints.Add(joint);
            SOPName_to_pendingJoint.Add(joint.ObjectNameInScene, joint);
        }

        // internal utility function: must be called within a lock (OdeLock)
        private void InternalRemovePendingJoint(PhysicsJoint joint)
        {
            pendingJoints.Remove(joint);
            SOPName_to_pendingJoint.Remove(joint.ObjectNameInScene);
        }

        // internal utility function: must be called within a lock (OdeLock)
        private void InternalRemoveActiveJoint(PhysicsJoint joint)
        {
            activeJoints.Remove(joint);
            SOPName_to_activeJoint.Remove(joint.ObjectNameInScene);
        }

        public override void DumpJointInfo()
        {
            string hdr = "[NINJA] JOINTINFO: ";
            foreach (PhysicsJoint j in pendingJoints)
            {
                m_log.Debug(hdr + " pending joint, Name: " + j.ObjectNameInScene + " raw parms:" + j.RawParams);
            }
            m_log.Debug(hdr + pendingJoints.Count + " total pending joints");
            foreach (string jointName in SOPName_to_pendingJoint.Keys)
            {
                m_log.Debug(hdr + " pending joints dict contains Name: " + jointName);
            }
            m_log.Debug(hdr + SOPName_to_pendingJoint.Keys.Count + " total pending joints dict entries");
            foreach (PhysicsJoint j in activeJoints)
            {
                m_log.Debug(hdr + " active joint, Name: " + j.ObjectNameInScene + " raw parms:" + j.RawParams);
            }
            m_log.Debug(hdr + activeJoints.Count + " total active joints");
            foreach (string jointName in SOPName_to_activeJoint.Keys)
            {
                m_log.Debug(hdr + " active joints dict contains Name: " + jointName);
            }
            m_log.Debug(hdr + SOPName_to_activeJoint.Keys.Count + " total active joints dict entries");

            m_log.Debug(hdr + " Per-body joint connectivity information follows.");
            m_log.Debug(hdr + joints_connecting_actor.Keys.Count + " bodies are connected by joints.");
            foreach (string actorName in joints_connecting_actor.Keys)
            {
                m_log.Debug(hdr + " Actor " + actorName + " has the following joints connecting it");
                foreach (PhysicsJoint j in joints_connecting_actor[actorName])
                {
                    m_log.Debug(hdr + " * joint Name: " + j.ObjectNameInScene + " raw parms:" + j.RawParams);
                }
                m_log.Debug(hdr + joints_connecting_actor[actorName].Count + " connecting joints total for this actor");
            }
        }

        public override void RequestJointDeletion(string ObjectNameInScene)
        {
            lock (externalJointRequestsLock)
            {
                if (!requestedJointsToBeDeleted.Contains(ObjectNameInScene)) // forbid same deletion request from entering twice to prevent spurious deletions processed asynchronously
                {
                    requestedJointsToBeDeleted.Add(ObjectNameInScene);
                }
            }
        }

        private void DeleteRequestedJoints()
        {
            List<string> myRequestedJointsToBeDeleted;
            lock (externalJointRequestsLock)
            {
                // make a local copy of the shared list for processing (threading issues)
                myRequestedJointsToBeDeleted = new List<string>(requestedJointsToBeDeleted);
            }

            foreach (string jointName in myRequestedJointsToBeDeleted)
            {
                lock (OdeLock)
                {
                    //m_log.Debug("[NINJA] trying to deleting requested joint " + jointName);
                    if (SOPName_to_activeJoint.ContainsKey(jointName) || SOPName_to_pendingJoint.ContainsKey(jointName))
                    {
                        OdePhysicsJoint joint = null;
                        if (SOPName_to_activeJoint.ContainsKey(jointName))
                        {
                            joint = SOPName_to_activeJoint[jointName] as OdePhysicsJoint;
                            InternalRemoveActiveJoint(joint);
                        }
                        else if (SOPName_to_pendingJoint.ContainsKey(jointName))
                        {
                            joint = SOPName_to_pendingJoint[jointName] as OdePhysicsJoint;
                            InternalRemovePendingJoint(joint);
                        }

                        if (joint != null)
                        {
                            //m_log.Debug("joint.BodyNames.Count is " + joint.BodyNames.Count + " and contents " + joint.BodyNames);
                            for (int iBodyName = 0; iBodyName < 2; iBodyName++)
                            {
                                string bodyName = joint.BodyNames[iBodyName];
                                if (bodyName != "NULL")
                                {
                                    joints_connecting_actor[bodyName].Remove(joint);
                                    if (joints_connecting_actor[bodyName].Count == 0)
                                    {
                                        joints_connecting_actor.Remove(bodyName);
                                    }
                                }
                            }

                            DoJointDeactivated(joint);
                            if (joint.jointID != IntPtr.Zero)
                            {
                                d.JointDestroy(joint.jointID);
                                joint.jointID = IntPtr.Zero;
                                //DoJointErrorMessage(joint, "successfully destroyed joint " + jointName);
                            }
                            else
                            {
                                //m_log.Warn("[NINJA] Ignoring re-request to destroy joint " + jointName);
                            }
                        }
                        else
                        {
                            // DoJointErrorMessage(joint, "coult not find joint to destroy based on name " + jointName);
                        }
                    }
                    else
                    {
                        // DoJointErrorMessage(joint, "WARNING - joint removal failed, joint " + jointName);
                    }
                }
            }

            // remove processed joints from the shared list
            lock (externalJointRequestsLock)
            {
                foreach (string jointName in myRequestedJointsToBeDeleted)
                {
                    requestedJointsToBeDeleted.Remove(jointName);
                }
            }
        }

        // for pending joints we don't know if their associated bodies exist yet or not.
        // the joint is actually created during processing of the taints
        private void CreateRequestedJoints()
        {
            List<PhysicsJoint> myRequestedJointsToBeCreated;
            lock (externalJointRequestsLock)
            {
                // make a local copy of the shared list for processing (threading issues)
                myRequestedJointsToBeCreated = new List<PhysicsJoint>(requestedJointsToBeCreated);
            }

            foreach (PhysicsJoint joint in myRequestedJointsToBeCreated)
            {
                lock (OdeLock)
                {
                    if (SOPName_to_pendingJoint.ContainsKey(joint.ObjectNameInScene) && SOPName_to_pendingJoint[joint.ObjectNameInScene] != null)
                    {
                        DoJointErrorMessage(joint, "WARNING: ignoring request to re-add already pending joint Name:" + joint.ObjectNameInScene + " type:" + joint.Type + " parms: " + joint.RawParams + " pos: " + joint.Position + " rot:" + joint.Rotation);
                        continue;
                    }
                    if (SOPName_to_activeJoint.ContainsKey(joint.ObjectNameInScene) && SOPName_to_activeJoint[joint.ObjectNameInScene] != null)
                    {
                        DoJointErrorMessage(joint, "WARNING: ignoring request to re-add already active joint Name:" + joint.ObjectNameInScene + " type:" + joint.Type + " parms: " + joint.RawParams + " pos: " + joint.Position + " rot:" + joint.Rotation);
                        continue;
                    }

                    InternalAddPendingJoint(joint as OdePhysicsJoint);

                    if (joint.BodyNames.Count >= 2)
                    {
                        for (int iBodyName = 0; iBodyName < 2; iBodyName++)
                        {
                            string bodyName = joint.BodyNames[iBodyName];
                            if (bodyName != "NULL")
                            {
                                if (!joints_connecting_actor.ContainsKey(bodyName))
                                {
                                    joints_connecting_actor.Add(bodyName, new List<PhysicsJoint>());
                                }
                                joints_connecting_actor[bodyName].Add(joint);
                            }
                        }
                    }
                }
            }

            // remove processed joints from shared list
            lock (externalJointRequestsLock)
            {
                foreach (PhysicsJoint joint in myRequestedJointsToBeCreated)
                {
                    requestedJointsToBeCreated.Remove(joint);
                }
            }

        }

        // public function to add an request for joint creation
        // this joint will just be added to a waiting list that is NOT processed during the main
        // Simulate() loop (to avoid deadlocks). After Simulate() is finished, we handle unprocessed joint requests.

        public override PhysicsJoint RequestJointCreation(string objectNameInScene, PhysicsJointType jointType, PhysicsVector position,
                                            Quaternion rotation, string parms, List<string> bodyNames, string trackedBodyName, Quaternion localRotation)

        {

            OdePhysicsJoint joint = new OdePhysicsJoint();
            joint.ObjectNameInScene = objectNameInScene;
            joint.Type = jointType;
            joint.Position = new PhysicsVector(position.X, position.Y, position.Z);
            joint.Rotation = rotation;
            joint.RawParams = parms;
            joint.BodyNames = new List<string>(bodyNames);
            joint.TrackedBodyName = trackedBodyName; 
            joint.LocalRotation = localRotation;
            joint.jointID = IntPtr.Zero;
            joint.ErrorMessageCount = 0;

            lock (externalJointRequestsLock)
            {
                if (!requestedJointsToBeCreated.Contains(joint)) // forbid same creation request from entering twice 
                {
                    requestedJointsToBeCreated.Add(joint);
                }
            }
            return joint;
        }

        private void RemoveAllJointsConnectedToActor(PhysicsActor actor)
        {
            //m_log.Debug("RemoveAllJointsConnectedToActor: start");
            if (actor.SOPName != null && joints_connecting_actor.ContainsKey(actor.SOPName) && joints_connecting_actor[actor.SOPName] != null)
            {

                List<PhysicsJoint> jointsToRemove = new List<PhysicsJoint>();
                //TODO: merge these 2 loops (originally it was needed to avoid altering a list being iterated over, but it is no longer needed due to the joint request queue mechanism)
                foreach (PhysicsJoint j in joints_connecting_actor[actor.SOPName])
                {
                    jointsToRemove.Add(j);
                }
                foreach (PhysicsJoint j in jointsToRemove)
                {
                    //m_log.Debug("RemoveAllJointsConnectedToActor: about to request deletion of " + j.ObjectNameInScene);
                    RequestJointDeletion(j.ObjectNameInScene);
                    //m_log.Debug("RemoveAllJointsConnectedToActor: done request deletion of " + j.ObjectNameInScene);
                    j.TrackedBodyName = null; // *IMMEDIATELY* prevent any further movement of this joint (else a deleted actor might cause spurious tracking motion of the joint for a few frames, leading to the joint proxy object disappearing)
                }
            }
        }

        public override void RemoveAllJointsConnectedToActorThreadLocked(PhysicsActor actor)
        {
            //m_log.Debug("RemoveAllJointsConnectedToActorThreadLocked: start");
            lock (OdeLock)
            {
                //m_log.Debug("RemoveAllJointsConnectedToActorThreadLocked: got lock");
                RemoveAllJointsConnectedToActor(actor);
            }
        }

        // normally called from within OnJointMoved, which is called from within a lock (OdeLock)
        public override PhysicsVector GetJointAnchor(PhysicsJoint joint)
        {
            Debug.Assert(joint.IsInPhysicsEngine);
            d.Vector3 pos = new d.Vector3();

            if (!(joint is OdePhysicsJoint))
            {
                DoJointErrorMessage(joint, "warning: non-ODE joint requesting anchor: " + joint.ObjectNameInScene);
            }
            else
            {
                OdePhysicsJoint odeJoint = (OdePhysicsJoint)joint;
                switch (odeJoint.Type)
                {
                    case PhysicsJointType.Ball:
                        d.JointGetBallAnchor(odeJoint.jointID, out pos);
                        break;
                    case PhysicsJointType.Hinge:
                        d.JointGetHingeAnchor(odeJoint.jointID, out pos);
                        break;
                }
            }
            return new PhysicsVector(pos.X, pos.Y, pos.Z);
        }

        // normally called from within OnJointMoved, which is called from within a lock (OdeLock)
        // WARNING: ODE sometimes returns <0,0,0> as the joint axis! Therefore this function
        // appears to be unreliable. Fortunately we can compute the joint axis ourselves by
        // keeping track of the joint's original orientation relative to one of the involved bodies.
        public override PhysicsVector GetJointAxis(PhysicsJoint joint)
        {
            Debug.Assert(joint.IsInPhysicsEngine);
            d.Vector3 axis = new d.Vector3();

            if (!(joint is OdePhysicsJoint))
            {
                DoJointErrorMessage(joint, "warning: non-ODE joint requesting anchor: " + joint.ObjectNameInScene);
            }
            else
            {
                OdePhysicsJoint odeJoint = (OdePhysicsJoint)joint;
                switch (odeJoint.Type)
                {
                    case PhysicsJointType.Ball:
                        DoJointErrorMessage(joint, "warning - axis requested for ball joint: " + joint.ObjectNameInScene);
                        break;
                    case PhysicsJointType.Hinge:
                        d.JointGetHingeAxis(odeJoint.jointID, out axis);
                        break;
                }
            }
            return new PhysicsVector(axis.X, axis.Y, axis.Z);
        }


        public void remActivePrim(OdePrim deactivatePrim)
        {
            lock (_activeprims)
            {
                _activeprims.Remove(deactivatePrim);
            }
        }

        public override void RemovePrim(PhysicsActor prim)
        {
            if (prim is OdePrim)
            {
                lock (OdeLock)
                {
                    OdePrim p = (OdePrim) prim;

                    p.setPrimForRemoval();
                    AddPhysicsActorTaint(prim);
                    //RemovePrimThreadLocked(p);
                }
            }
        }

        /// <summary>
        /// This is called from within simulate but outside the locked portion
        /// We need to do our own locking here
        /// Essentially, we need to remove the prim from our space segment, whatever segment it's in.
        ///
        /// If there are no more prim in the segment, we need to empty (spacedestroy)the segment and reclaim memory
        /// that the space was using.
        /// </summary>
        /// <param name="prim"></param>
        public void RemovePrimThreadLocked(OdePrim prim)
        {
            lock (prim)
            {
                remCollisionEventReporting(prim);
                lock (ode)
                {
                    if (prim.prim_geom != IntPtr.Zero)
                    {
                        prim.ResetTaints();

                        if (prim.IsPhysical)
                        {
                            prim.disableBody();
                            if (prim.childPrim)
                            {
                                prim.childPrim = false;
                                prim.Body = IntPtr.Zero;
                                prim.m_disabled = true;
                                prim.IsPhysical = false;
                            }


                        }
                        // we don't want to remove the main space

                        // If the geometry is in the targetspace, remove it from the target space
                        //m_log.Warn(prim.m_targetSpace);

                        //if (prim.m_targetSpace != IntPtr.Zero)
                        //{
                        //if (d.SpaceQuery(prim.m_targetSpace, prim.prim_geom))
                        //{

                        //if (d.GeomIsSpace(prim.m_targetSpace))
                        //{
                        //waitForSpaceUnlock(prim.m_targetSpace);
                        //d.SpaceRemove(prim.m_targetSpace, prim.prim_geom);
                        prim.m_targetSpace = IntPtr.Zero;
                        //}
                        //else
                        //{
                        // m_log.Info("[Physics]: Invalid Scene passed to 'removeprim from scene':" +
                        //((OdePrim)prim).m_targetSpace.ToString());
                        //}

                        //}
                        //}
                        //m_log.Warn(prim.prim_geom);
                        try
                        {
                            if (prim.prim_geom != IntPtr.Zero)
                            {
                                d.GeomDestroy(prim.prim_geom);
                                prim.prim_geom = IntPtr.Zero;
                            }
                            else
                            {
                                m_log.Warn("[PHYSICS]: Unable to remove prim from physics scene");
                            }
                        }
                        catch (AccessViolationException)
                        {
                            m_log.Info("[PHYSICS]: Couldn't remove prim from physics scene, it was already be removed.");
                        }
                        lock (_prims)
                        _prims.Remove(prim);

                        //If there are no more geometries in the sub-space, we don't need it in the main space anymore
                        //if (d.SpaceGetNumGeoms(prim.m_targetSpace) == 0)
                        //{
                        //if (prim.m_targetSpace != null)
                        //{
                        //if (d.GeomIsSpace(prim.m_targetSpace))
                        //{
                        //waitForSpaceUnlock(prim.m_targetSpace);
                        //d.SpaceRemove(space, prim.m_targetSpace);
                        // free up memory used by the space.
                        //d.SpaceDestroy(prim.m_targetSpace);
                        //int[] xyspace = calculateSpaceArrayItemFromPos(prim.Position);
                        //resetSpaceArrayItemToZero(xyspace[0], xyspace[1]);
                        //}
                        //else
                        //{
                        //m_log.Info("[Physics]: Invalid Scene passed to 'removeprim from scene':" +
                        //((OdePrim) prim).m_targetSpace.ToString());
                        //}
                        //}
                        //}

                        if (SupportsNINJAJoints)
                        {
                            RemoveAllJointsConnectedToActorThreadLocked(prim);
                        }
                    }
                }
            }
        }

        #endregion

        #region Space Separation Calculation

        /// <summary>
        /// Takes a space pointer and zeros out the array we're using to hold the spaces
        /// </summary>
        /// <param name="pSpace"></param>
        public void resetSpaceArrayItemToZero(IntPtr pSpace)
        {
            for (int x = 0; x < staticPrimspace.GetLength(0); x++)
            {
                for (int y = 0; y < staticPrimspace.GetLength(1); y++)
                {
                    if (staticPrimspace[x, y] == pSpace)
                        staticPrimspace[x, y] = IntPtr.Zero;
                }
            }
        }

        public void resetSpaceArrayItemToZero(int arrayitemX, int arrayitemY)
        {
            staticPrimspace[arrayitemX, arrayitemY] = IntPtr.Zero;
        }

        /// <summary>
        /// Called when a static prim moves.  Allocates a space for the prim based on it's position
        /// </summary>
        /// <param name="geom">the pointer to the geom that moved</param>
        /// <param name="pos">the position that the geom moved to</param>
        /// <param name="currentspace">a pointer to the space it was in before it was moved.</param>
        /// <returns>a pointer to the new space it's in</returns>
        public IntPtr recalculateSpaceForGeom(IntPtr geom, PhysicsVector pos, IntPtr currentspace)
        {
            // Called from setting the Position and Size of an ODEPrim so
            // it's already in locked space.

            // we don't want to remove the main space
            // we don't need to test physical here because this function should
            // never be called if the prim is physical(active)

            // All physical prim end up in the root space
            //Thread.Sleep(20);
            if (currentspace != space)
            {
                //m_log.Info("[SPACE]: C:" + currentspace.ToString() + " g:" + geom.ToString());
                //if (currentspace == IntPtr.Zero)
               //{
                    //int adfadf = 0;
                //}
                if (d.SpaceQuery(currentspace, geom) && currentspace != IntPtr.Zero)
                {
                    if (d.GeomIsSpace(currentspace))
                    {
                        waitForSpaceUnlock(currentspace);
                        d.SpaceRemove(currentspace, geom);
                    }
                    else
                    {
                        m_log.Info("[Physics]: Invalid Scene passed to 'recalculatespace':" + currentspace +
                                   " Geom:" + geom);
                    }
                }
                else
                {
                    IntPtr sGeomIsIn = d.GeomGetSpace(geom);
                    if (sGeomIsIn != IntPtr.Zero)
                    {
                        if (d.GeomIsSpace(currentspace))
                        {
                            waitForSpaceUnlock(sGeomIsIn);
                            d.SpaceRemove(sGeomIsIn, geom);
                        }
                        else
                        {
                            m_log.Info("[Physics]: Invalid Scene passed to 'recalculatespace':" +
                                       sGeomIsIn + " Geom:" + geom);
                        }
                    }
                }

                //If there are no more geometries in the sub-space, we don't need it in the main space anymore
                if (d.SpaceGetNumGeoms(currentspace) == 0)
                {
                    if (currentspace != IntPtr.Zero)
                    {
                        if (d.GeomIsSpace(currentspace))
                        {
                            waitForSpaceUnlock(currentspace);
                            waitForSpaceUnlock(space);
                            d.SpaceRemove(space, currentspace);
                            // free up memory used by the space.

                            //d.SpaceDestroy(currentspace);
                            resetSpaceArrayItemToZero(currentspace);
                        }
                        else
                        {
                            m_log.Info("[Physics]: Invalid Scene passed to 'recalculatespace':" +
                                       currentspace + " Geom:" + geom);
                        }
                    }
                }
            }
            else
            {
                // this is a physical object that got disabled. ;.;
                if (currentspace != IntPtr.Zero && geom != IntPtr.Zero)
                {
                    if (d.SpaceQuery(currentspace, geom))
                    {
                        if (d.GeomIsSpace(currentspace))
                        {
                            waitForSpaceUnlock(currentspace);
                            d.SpaceRemove(currentspace, geom);
                        }
                        else
                        {
                            m_log.Info("[Physics]: Invalid Scene passed to 'recalculatespace':" +
                                       currentspace + " Geom:" + geom);
                        }
                    }
                    else
                    {
                        IntPtr sGeomIsIn = d.GeomGetSpace(geom);
                        if (sGeomIsIn != IntPtr.Zero)
                        {
                            if (d.GeomIsSpace(sGeomIsIn))
                            {
                                waitForSpaceUnlock(sGeomIsIn);
                                d.SpaceRemove(sGeomIsIn, geom);
                            }
                            else
                            {
                                m_log.Info("[Physics]: Invalid Scene passed to 'recalculatespace':" +
                                           sGeomIsIn + " Geom:" + geom);
                            }
                        }
                    }
                }
            }

            // The routines in the Position and Size sections do the 'inserting' into the space,
            // so all we have to do is make sure that the space that we're putting the prim into
            // is in the 'main' space.
            int[] iprimspaceArrItem = calculateSpaceArrayItemFromPos(pos);
            IntPtr newspace = calculateSpaceForGeom(pos);

            if (newspace == IntPtr.Zero)
            {
                newspace = createprimspace(iprimspaceArrItem[0], iprimspaceArrItem[1]);
                d.HashSpaceSetLevels(newspace, smallHashspaceLow, smallHashspaceHigh);
            }

            return newspace;
        }

        /// <summary>
        /// Creates a new space at X Y
        /// </summary>
        /// <param name="iprimspaceArrItemX"></param>
        /// <param name="iprimspaceArrItemY"></param>
        /// <returns>A pointer to the created space</returns>
        public IntPtr createprimspace(int iprimspaceArrItemX, int iprimspaceArrItemY)
        {
            // creating a new space for prim and inserting it into main space.
            staticPrimspace[iprimspaceArrItemX, iprimspaceArrItemY] = d.HashSpaceCreate(IntPtr.Zero);
            d.GeomSetCategoryBits(staticPrimspace[iprimspaceArrItemX, iprimspaceArrItemY], (int)CollisionCategories.Space);
            waitForSpaceUnlock(space);
            d.SpaceSetSublevel(space, 1);
            d.SpaceAdd(space, staticPrimspace[iprimspaceArrItemX, iprimspaceArrItemY]);
            return staticPrimspace[iprimspaceArrItemX, iprimspaceArrItemY];
        }

        /// <summary>
        /// Calculates the space the prim should be in by its position
        /// </summary>
        /// <param name="pos"></param>
        /// <returns>a pointer to the space. This could be a new space or reused space.</returns>
        public IntPtr calculateSpaceForGeom(PhysicsVector pos)
        {
            int[] xyspace = calculateSpaceArrayItemFromPos(pos);
            //m_log.Info("[Physics]: Attempting to use arrayItem: " + xyspace[0].ToString() + "," + xyspace[1].ToString());
            return staticPrimspace[xyspace[0], xyspace[1]];
        }

        /// <summary>
        /// Holds the space allocation logic
        /// </summary>
        /// <param name="pos"></param>
        /// <returns>an array item based on the position</returns>
        public int[] calculateSpaceArrayItemFromPos(PhysicsVector pos)
        {
            int[] returnint = new int[2];

            returnint[0] = (int) (pos.X/metersInSpace);

            if (returnint[0] > ((int) (259f/metersInSpace)))
                returnint[0] = ((int) (259f/metersInSpace));
            if (returnint[0] < 0)
                returnint[0] = 0;

            returnint[1] = (int) (pos.Y/metersInSpace);
            if (returnint[1] > ((int) (259f/metersInSpace)))
                returnint[1] = ((int) (259f/metersInSpace));
            if (returnint[1] < 0)
                returnint[1] = 0;

            return returnint;
        }

        #endregion

        /// <summary>
        /// Routine to figure out if we need to mesh this prim with our mesher
        /// </summary>
        /// <param name="pbs"></param>
        /// <returns></returns>
        public bool needsMeshing(PrimitiveBaseShape pbs)
        {
            // most of this is redundant now as the mesher will return null if it cant mesh a prim
            // but we still need to check for sculptie meshing being enabled so this is the most
            // convenient place to do it for now...

        //    //if (pbs.PathCurve == (byte)Primitive.PathCurve.Circle && pbs.ProfileCurve == (byte)Primitive.ProfileCurve.Circle && pbs.PathScaleY <= 0.75f)
        //    //m_log.Debug("needsMeshing: " + " pathCurve: " + pbs.PathCurve.ToString() + " profileCurve: " + pbs.ProfileCurve.ToString() + " pathScaleY: " + Primitive.UnpackPathScale(pbs.PathScaleY).ToString());
            int iPropertiesNotSupportedDefault = 0;

            if (pbs.SculptEntry && !meshSculptedPrim)
            {
#if SPAM
                m_log.Warn("NonMesh");
#endif
                return false;
            }

            // if it's a standard box or sphere with no cuts, hollows, twist or top shear, return false since ODE can use an internal representation for the prim
            if ((pbs.ProfileShape == ProfileShape.Square && pbs.PathCurve == (byte)Extrusion.Straight)
                || (pbs.ProfileShape == ProfileShape.HalfCircle && pbs.PathCurve == (byte)Extrusion.Curve1
                && pbs.Scale.X == pbs.Scale.Y && pbs.Scale.Y == pbs.Scale.Z))
            {

                if (pbs.ProfileBegin == 0 && pbs.ProfileEnd == 0
                    && pbs.ProfileHollow == 0
                    && pbs.PathTwist == 0 && pbs.PathTwistBegin == 0
                    && pbs.PathBegin == 0 && pbs.PathEnd == 0
                    && pbs.PathTaperX == 0 && pbs.PathTaperY == 0
                    && pbs.PathScaleX == 100 && pbs.PathScaleY == 100
                    && pbs.PathShearX == 0 && pbs.PathShearY == 0)
                {
#if SPAM
                    m_log.Warn("NonMesh");
#endif
                    return false;
                }
            }

            if (pbs.ProfileHollow != 0)
                iPropertiesNotSupportedDefault++;

            if ((pbs.PathTwistBegin != 0) || (pbs.PathTwist != 0))
                iPropertiesNotSupportedDefault++; 

            if ((pbs.ProfileBegin != 0) || pbs.ProfileEnd != 0)
                iPropertiesNotSupportedDefault++;

            if ((pbs.PathScaleX != 100) || (pbs.PathScaleY != 100))
                iPropertiesNotSupportedDefault++;

            if ((pbs.PathShearX != 0) || (pbs.PathShearY != 0))
                iPropertiesNotSupportedDefault++;

            if (pbs.ProfileShape == ProfileShape.Circle && pbs.PathCurve == (byte)Extrusion.Straight)
                iPropertiesNotSupportedDefault++;

            if (pbs.ProfileShape == ProfileShape.HalfCircle && pbs.PathCurve == (byte)Extrusion.Curve1 && (pbs.Scale.X != pbs.Scale.Y || pbs.Scale.Y != pbs.Scale.Z || pbs.Scale.Z != pbs.Scale.X))
                iPropertiesNotSupportedDefault++;

            if (pbs.ProfileShape == ProfileShape.HalfCircle && pbs.PathCurve == (byte) Extrusion.Curve1)
                iPropertiesNotSupportedDefault++;

            // test for torus
            if ((pbs.ProfileCurve & 0x07) == (byte)ProfileShape.Square)
            {
                if (pbs.PathCurve == (byte)Extrusion.Curve1)
                {
                    iPropertiesNotSupportedDefault++;
                }
            }
            else if ((pbs.ProfileCurve & 0x07) == (byte)ProfileShape.Circle)
            {
                if (pbs.PathCurve == (byte)Extrusion.Straight)
                {
                    iPropertiesNotSupportedDefault++;
                }

                // ProfileCurve seems to combine hole shape and profile curve so we need to only compare against the lower 3 bits
                else if (pbs.PathCurve == (byte)Extrusion.Curve1)
                {
                    iPropertiesNotSupportedDefault++;
                }
            }
            else if ((pbs.ProfileCurve & 0x07) == (byte)ProfileShape.HalfCircle)
            {
                if (pbs.PathCurve == (byte)Extrusion.Curve1 || pbs.PathCurve == (byte)Extrusion.Curve2)
                {
                    iPropertiesNotSupportedDefault++;
                }
            }
            else if ((pbs.ProfileCurve & 0x07) == (byte)ProfileShape.EquilateralTriangle)
            {
                if (pbs.PathCurve == (byte)Extrusion.Straight)
                {
                    iPropertiesNotSupportedDefault++;
                }
                else if (pbs.PathCurve == (byte)Extrusion.Curve1)
                {
                    iPropertiesNotSupportedDefault++;
                }
            }


            if (iPropertiesNotSupportedDefault == 0)
            {
#if SPAM              
                m_log.Warn("NonMesh");
#endif
                return false;
            }
#if SPAM
            m_log.Debug("Mesh");
#endif
            return true; 
        }

        /// <summary>
        /// Called after our prim properties are set Scale, position etc.
        /// We use this event queue like method to keep changes to the physical scene occuring in the threadlocked mutex
        /// This assures us that we have no race conditions
        /// </summary>
        /// <param name="prim"></param>
        public override void AddPhysicsActorTaint(PhysicsActor prim)
        {
            
            if (prim is OdePrim)
            {
                OdePrim taintedprim = ((OdePrim) prim);
                lock (_taintedPrim)
                {
                    if (!(_taintedPrim.Contains(taintedprim)))
                        _taintedPrim.Add(taintedprim);
                }
                return;
            }
            else if (prim is OdeCharacter)
            {
                OdeCharacter taintedchar = ((OdeCharacter)prim);
                lock (_taintedActors)
                {
                    if (!(_taintedActors.Contains(taintedchar)))
                        _taintedActors.Add(taintedchar);
                }
            }
        }

        /// <summary>
        /// This is our main simulate loop
        /// It's thread locked by a Mutex in the scene.
        /// It holds Collisions, it instructs ODE to step through the physical reactions
        /// It moves the objects around in memory
        /// It calls the methods that report back to the object owners.. (scenepresence, SceneObjectGroup)
        /// </summary>
        /// <param name="timeStep"></param>
        /// <returns></returns>
        public override float Simulate(float timeStep)
        {
            if (framecount >= int.MaxValue)
                framecount = 0;

            framecount++;

            float fps = 0;
            //m_log.Info(timeStep.ToString());
            step_time += timeStep;

            // If We're loaded down by something else,
            // or debugging with the Visual Studio project on pause
            // skip a few frames to catch up gracefully.
            // without shooting the physicsactors all over the place

            if (step_time >= m_SkipFramesAtms)
            {
                // Instead of trying to catch up, it'll do 5 physics frames only
                step_time = ODE_STEPSIZE;
                m_physicsiterations = 5;
            }
            else
            {
                m_physicsiterations = 10;
            }

            if (SupportsNINJAJoints)
            {
                DeleteRequestedJoints(); // this must be outside of the lock (OdeLock) to avoid deadlocks
                CreateRequestedJoints(); // this must be outside of the lock (OdeLock) to avoid deadlocks
            }

            lock (OdeLock)
            {
                // Process 10 frames if the sim is running normal..
                // process 5 frames if the sim is running slow
                //try
                //{
                    //d.WorldSetQuickStepNumIterations(world, m_physicsiterations);
                //}
                //catch (StackOverflowException)
                //{
                   // m_log.Error("[PHYSICS]: The operating system wasn't able to allocate enough memory for the simulation.  Restarting the sim.");
                   // ode.drelease(world);
                    //base.TriggerPhysicsBasedRestart();
                //}

                int i = 0;

                // Figure out the Frames Per Second we're going at.
                //(step_time == 0.004f, there's 250 of those per second.   Times the step time/step size
                
                fps = (step_time/ODE_STEPSIZE) * 1000;

                step_time = 0.09375f;

                while (step_time > 0.0f)
                {
                    //lock (ode)
                    //{
                        //if (!ode.lockquery())
                        //{
                           // ode.dlock(world);
                            try
                            { 
                                // Insert, remove Characters
                                bool processedtaints = false;

                                lock (_taintedActors)
                                {
                                    if (_taintedActors.Count > 0)
                                    {
                                        foreach (OdeCharacter character in _taintedActors)
                                        {

                                            character.ProcessTaints(timeStep);

                                            processedtaints = true;
                                            //character.m_collisionscore = 0;
                                        }

                                        if (processedtaints)
                                            _taintedActors.Clear();
                                    }
                                }

                                // Modify other objects in the scene.
                                processedtaints = false;

                                lock (_taintedPrim)
                                {
                                    foreach (OdePrim prim in _taintedPrim)
                                    {
                                        if (prim.m_taintremove)
                                        {
                                            RemovePrimThreadLocked(prim);
                                        }
                                        else
                                        {
                                            prim.ProcessTaints(timeStep);
                                        }
                                        processedtaints = true;
                                        prim.m_collisionscore = 0;
                                    }

                                    if (SupportsNINJAJoints)
                                    {
                                        // Create pending joints, if possible

                                        // joints can only be processed after ALL bodies are processed (and exist in ODE), since creating
                                        // a joint requires specifying the body id of both involved bodies
                                        if (pendingJoints.Count > 0)
                                        {
                                            List<PhysicsJoint> successfullyProcessedPendingJoints = new List<PhysicsJoint>();
                                            //DoJointErrorMessage(joints_connecting_actor, "taint: " + pendingJoints.Count + " pending joints");
                                            foreach (PhysicsJoint joint in pendingJoints)
                                            {
                                                //DoJointErrorMessage(joint, "taint: time to create joint with parms: " + joint.RawParams);
                                                string[] jointParams = joint.RawParams.Split(" ".ToCharArray(), System.StringSplitOptions.RemoveEmptyEntries);
                                                List<IntPtr> jointBodies = new List<IntPtr>();
                                                bool allJointBodiesAreReady = true;
                                                foreach (string jointParam in jointParams)
                                                {
                                                    if (jointParam == "NULL")
                                                    {
                                                        //DoJointErrorMessage(joint, "attaching NULL joint to world");
                                                        jointBodies.Add(IntPtr.Zero);
                                                    }
                                                    else
                                                    {
                                                        //DoJointErrorMessage(joint, "looking for prim name: " + jointParam);
                                                        bool foundPrim = false;
                                                        lock (_prims)
                                                        {
                                                            foreach (OdePrim prim in _prims) // FIXME: inefficient
                                                            {
                                                                if (prim.SOPName == jointParam)
                                                                {
                                                                    //DoJointErrorMessage(joint, "found for prim name: " + jointParam);
                                                                    if (prim.IsPhysical && prim.Body != IntPtr.Zero)
                                                                    {
                                                                        jointBodies.Add(prim.Body);
                                                                        foundPrim = true;
                                                                        break;
                                                                    }
                                                                    else
                                                                    {
                                                                        DoJointErrorMessage(joint, "prim name " + jointParam +
                                                                            " exists but is not (yet) physical; deferring joint creation. " +
                                                                            "IsPhysical property is " + prim.IsPhysical +
                                                                            " and body is " + prim.Body);
                                                                        foundPrim = false;
                                                                        break;
                                                                    }
                                                                }
                                                            }
                                                        }
                                                        if (foundPrim)
                                                        {
                                                            // all is fine
                                                        }
                                                        else
                                                        {
                                                            allJointBodiesAreReady = false;
                                                            break;
                                                        }
                                                    }
                                                }
                                                if (allJointBodiesAreReady)
                                                {
                                                    //DoJointErrorMessage(joint, "allJointBodiesAreReady for " + joint.ObjectNameInScene + " with parms " + joint.RawParams);
                                                    if (jointBodies[0] == jointBodies[1])
                                                    {
                                                        DoJointErrorMessage(joint, "ERROR: joint cannot be created; the joint bodies are the same, body1==body2. Raw body is " + jointBodies[0] + ". raw parms: " + joint.RawParams);
                                                    }
                                                    else
                                                    {
                                                        switch (joint.Type)
                                                        {
                                                            case PhysicsJointType.Ball:
                                                                {
                                                                    IntPtr odeJoint;
                                                                    //DoJointErrorMessage(joint, "ODE creating ball joint ");
                                                                    odeJoint = d.JointCreateBall(world, IntPtr.Zero);
                                                                    //DoJointErrorMessage(joint, "ODE attaching ball joint: " + odeJoint + " with b1:" + jointBodies[0] + " b2:" + jointBodies[1]);
                                                                    d.JointAttach(odeJoint, jointBodies[0], jointBodies[1]);
                                                                    //DoJointErrorMessage(joint, "ODE setting ball anchor: " + odeJoint + " to vec:" + joint.Position);
                                                                    d.JointSetBallAnchor(odeJoint,
                                                                                        joint.Position.X,
                                                                                        joint.Position.Y,
                                                                                        joint.Position.Z);
                                                                    //DoJointErrorMessage(joint, "ODE joint setting OK");
                                                                    //DoJointErrorMessage(joint, "The ball joint's bodies are here: b0: ");
                                                                    //DoJointErrorMessage(joint, "" + (jointBodies[0] != IntPtr.Zero ? "" + d.BodyGetPosition(jointBodies[0]) : "fixed environment"));
                                                                    //DoJointErrorMessage(joint, "The ball joint's bodies are here: b1: ");
                                                                    //DoJointErrorMessage(joint, "" + (jointBodies[1] != IntPtr.Zero ? "" + d.BodyGetPosition(jointBodies[1]) : "fixed environment"));

                                                                    if (joint is OdePhysicsJoint)
                                                                    {
                                                                        ((OdePhysicsJoint)joint).jointID = odeJoint;
                                                                    }
                                                                    else
                                                                    {
                                                                        DoJointErrorMessage(joint, "WARNING: non-ode joint in ODE!");
                                                                    }
                                                                }
                                                                break;
                                                            case PhysicsJointType.Hinge:
                                                                {
                                                                    IntPtr odeJoint;
                                                                    //DoJointErrorMessage(joint, "ODE creating hinge joint ");
                                                                    odeJoint = d.JointCreateHinge(world, IntPtr.Zero);
                                                                    //DoJointErrorMessage(joint, "ODE attaching hinge joint: " + odeJoint + " with b1:" + jointBodies[0] + " b2:" + jointBodies[1]);
                                                                    d.JointAttach(odeJoint, jointBodies[0], jointBodies[1]);
                                                                    //DoJointErrorMessage(joint, "ODE setting hinge anchor: " + odeJoint + " to vec:" + joint.Position);
                                                                    d.JointSetHingeAnchor(odeJoint,
                                                                                          joint.Position.X,
                                                                                          joint.Position.Y,
                                                                                          joint.Position.Z);
                                                                    // We use the orientation of the x-axis of the joint's coordinate frame
                                                                    // as the axis for the hinge. 

                                                                    // Therefore, we must get the joint's coordinate frame based on the
                                                                    // joint.Rotation field, which originates from the orientation of the 
                                                                    // joint's proxy object in the scene.

                                                                    // The joint's coordinate frame is defined as the transformation matrix
                                                                    // that converts a vector from joint-local coordinates into world coordinates.
                                                                    // World coordinates are defined as the XYZ coordinate system of the sim,
                                                                    // as shown in the top status-bar of the viewer.

                                                                    // Once we have the joint's coordinate frame, we extract its X axis (AtAxis)
                                                                    // and use that as the hinge axis.

                                                                    //joint.Rotation.Normalize();
                                                                    Matrix4 proxyFrame = Matrix4.CreateFromQuaternion(joint.Rotation);

                                                                    // Now extract the X axis of the joint's coordinate frame.

                                                                    // Do not try to use proxyFrame.AtAxis or you will become mired in the
                                                                    // tar pit of transposed, inverted, and generally messed-up orientations.
                                                                    // (In other words, Matrix4.AtAxis() is borked.)
                                                                    // Vector3 jointAxis = proxyFrame.AtAxis; <--- this path leadeth to madness

                                                                    // Instead, compute the X axis of the coordinate frame by transforming
                                                                    // the (1,0,0) vector. At least that works.

                                                                    //m_log.Debug("PHY: making axis: complete matrix is " + proxyFrame);
                                                                    Vector3 jointAxis = Vector3.Transform(Vector3.UnitX, proxyFrame);
                                                                    //m_log.Debug("PHY: making axis: hinge joint axis is " + jointAxis); 
                                                                    //DoJointErrorMessage(joint, "ODE setting hinge axis: " + odeJoint + " to vec:" + jointAxis);
                                                                    d.JointSetHingeAxis(odeJoint,
                                                                                        jointAxis.X,
                                                                                        jointAxis.Y,
                                                                                        jointAxis.Z);
                                                                    //d.JointSetHingeParam(odeJoint, (int)dParam.CFM, 0.1f);
                                                                    if (joint is OdePhysicsJoint)
                                                                    {
                                                                        ((OdePhysicsJoint)joint).jointID = odeJoint;
                                                                    }
                                                                    else
                                                                    {
                                                                        DoJointErrorMessage(joint, "WARNING: non-ode joint in ODE!");
                                                                    }
                                                                }
                                                                break;
                                                        }
                                                        successfullyProcessedPendingJoints.Add(joint);
                                                    }
                                                }
                                                else
                                                {
                                                    DoJointErrorMessage(joint, "joint could not yet be created; still pending");
                                                }
                                            }
                                            foreach (PhysicsJoint successfullyProcessedJoint in successfullyProcessedPendingJoints)
                                            {
                                                //DoJointErrorMessage(successfullyProcessedJoint, "finalizing succesfully procsssed joint " + successfullyProcessedJoint.ObjectNameInScene + " parms " + successfullyProcessedJoint.RawParams);
                                                //DoJointErrorMessage(successfullyProcessedJoint, "removing from pending");
                                                InternalRemovePendingJoint(successfullyProcessedJoint);
                                                //DoJointErrorMessage(successfullyProcessedJoint, "adding to active");
                                                InternalAddActiveJoint(successfullyProcessedJoint);
                                                //DoJointErrorMessage(successfullyProcessedJoint, "done");
                                            }
                                        }
                                    }

                                    if (processedtaints)
                                        _taintedPrim.Clear();
                                }

                                // Move characters
                                lock (_characters)
                                {
                                    foreach (OdeCharacter actor in _characters)
                                    {
                                        if (actor != null)
                                            actor.Move(timeStep);
                                    }
                                }

                                // Move other active objects
                                lock (_activeprims)
                                {
                                    foreach (OdePrim prim in _activeprims)
                                    {
                                        prim.m_collisionscore = 0;
                                        prim.Move(timeStep);
                                    }
                                }

                                //if ((framecount % m_randomizeWater) == 0)
                                   // randomizeWater(waterlevel);

                                collision_optimized(timeStep);

                                lock (_collisionEventPrim)
                                {
                                    foreach (PhysicsActor obj in _collisionEventPrim)
                                    {
                                        if (obj == null)
                                            continue;

                                        switch ((ActorTypes)obj.PhysicsActorType)
                                        {
                                            case ActorTypes.Agent:
                                                OdeCharacter cobj = (OdeCharacter)obj;
                                                cobj.SendCollisions();
                                                break;
                                            case ActorTypes.Prim:
                                                OdePrim pobj = (OdePrim)obj;
                                                pobj.SendCollisions();
                                                break;
                                        }
                                    }
                                }

                                //if (m_global_contactcount > 5)
                                //{
                                //    m_log.DebugFormat("[PHYSICS]: Contacts:{0}", m_global_contactcount);
                                //}

                                m_global_contactcount = 0;
                                
                                d.WorldQuickStep(world, ODE_STEPSIZE);
                                d.JointGroupEmpty(contactgroup);
                                //ode.dunlock(world);
                            }
                            catch (Exception e)
                            {
                                m_log.ErrorFormat("[PHYSICS]: {0}, {1}, {2}", e.Message, e.TargetSite, e);
                                ode.dunlock(world);
                            }

                            step_time -= ODE_STEPSIZE;
                            i++;
                        //}
                        //else
                        //{
                            //fps = 0;
                        //}
                    //}
                }

                lock (_characters)
                {
                    foreach (OdeCharacter actor in _characters)
                    {
                        if (actor != null)
                            actor.UpdatePositionAndVelocity();
                    }
                }

                lock (_activeprims)
                {
                    //if (timeStep < 0.2f)
                    {
                        foreach (OdePrim actor in _activeprims)
                        {
                            if (actor.IsPhysical && (d.BodyIsEnabled(actor.Body) || !actor._zeroFlag))
                            {
                                actor.UpdatePositionAndVelocity();

                                if (SupportsNINJAJoints)
                                {
                                    // If an actor moved, move its joint proxy objects as well.
                                    // There seems to be an event PhysicsActor.OnPositionUpdate that could be used
                                    // for this purpose but it is never called! So we just do the joint
                                    // movement code here.

                                    if (actor.SOPName != null &&
                                        joints_connecting_actor.ContainsKey(actor.SOPName) &&
                                        joints_connecting_actor[actor.SOPName] != null &&
                                        joints_connecting_actor[actor.SOPName].Count > 0)
                                    {
                                        foreach (PhysicsJoint affectedJoint in joints_connecting_actor[actor.SOPName])
                                        {
                                            if (affectedJoint.IsInPhysicsEngine)
                                            {
                                                DoJointMoved(affectedJoint);
                                            }
                                            else
                                            {
                                                DoJointErrorMessage(affectedJoint, "a body connected to a joint was moved, but the joint doesn't exist yet! this will lead to joint error. joint was: " + affectedJoint.ObjectNameInScene + " parms:" + affectedJoint.RawParams);
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }

                //DumpJointInfo();

                // Finished with all sim stepping. If requested, dump world state to file for debugging.
                // TODO: This call to the export function is already inside lock (OdeLock) - but is an extra lock needed?
                // TODO: This overwrites all dump files in-place. Should this be a growing logfile, or separate snapshots?
                if (physics_logging && (physics_logging_interval>0) && (framecount % physics_logging_interval == 0))
                {
                    string fname = "state-" + world.ToString() + ".DIF"; // give each physics world a separate filename
                    string prefix = "world" + world.ToString(); // prefix for variable names in exported .DIF file

                    if (physics_logging_append_existing_logfile)
                    {
                        string header = "-------------- START OF PHYSICS FRAME " + framecount.ToString() + " --------------";
                        TextWriter fwriter = File.AppendText(fname);
                        fwriter.WriteLine(header);
                        fwriter.Close();
                    }
                    d.WorldExportDIF(world, fname, physics_logging_append_existing_logfile, prefix);
                }
            }

            return fps;
        }

        public override void GetResults()
        {
        }

        public override bool IsThreaded
        {
            // for now we won't be multithreaded
            get { return (false); }
        }

        #region ODE Specific Terrain Fixes
        public float[] ResizeTerrain512NearestNeighbour(float[] heightMap)
        {
            float[] returnarr = new float[262144];
            float[,] resultarr = new float[m_regionWidth, m_regionHeight];

            // Filling out the array into it's multi-dimentional components
            for (int y = 0; y < m_regionHeight; y++)
            {
                for (int x = 0; x < m_regionWidth; x++)
                {
                    resultarr[y, x] = heightMap[y * m_regionWidth + x];
                }
            }

            // Resize using Nearest Neighbour

            // This particular way is quick but it only works on a multiple of the original

            // The idea behind this method can be described with the following diagrams
            // second pass and third pass happen in the same loop really..  just separated
            // them to show what this does.

            // First Pass
            // ResultArr:
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1

            // Second Pass
            // ResultArr2:
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,

            // Third pass fills in the blanks
            // ResultArr2:
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1

            // X,Y = .
            // X+1,y = ^
            // X,Y+1 = *
            // X+1,Y+1 = #

            // Filling in like this;
            // .*
            // ^#
            // 1st .
            // 2nd *
            // 3rd ^
            // 4th #
            // on single loop.

            float[,] resultarr2 = new float[512, 512];
            for (int y = 0; y < m_regionHeight; y++)
            {
                for (int x = 0; x < m_regionWidth; x++)
                {
                    resultarr2[y * 2, x * 2] = resultarr[y, x];

                    if (y < m_regionHeight)
                    {
                        resultarr2[(y * 2) + 1, x * 2] = resultarr[y, x];
                    }
                    if (x < m_regionWidth)
                    {
                        resultarr2[y * 2, (x * 2) + 1] = resultarr[y, x];
                    }
                    if (x < m_regionWidth && y < m_regionHeight)
                    {
                        resultarr2[(y * 2) + 1, (x * 2) + 1] = resultarr[y, x];
                    }
                }
            }

            //Flatten out the array
            int i = 0;
            for (int y = 0; y < 512; y++)
            {
                for (int x = 0; x < 512; x++)
                {
                    if (resultarr2[y, x] <= 0)
                        returnarr[i] = 0.0000001f;
                    else
                        returnarr[i] = resultarr2[y, x];

                    i++;
                }
            }

            return returnarr;
        }

        public float[] ResizeTerrain512Interpolation(float[] heightMap)
        {
            float[] returnarr = new float[262144];
            float[,] resultarr = new float[m_regionWidth,m_regionHeight];

            // Filling out the array into it's multi-dimentional components
            for (int y = 0; y < m_regionHeight; y++)
            {
                for (int x = 0; x < m_regionWidth; x++)
                {
                    resultarr[y, x] = heightMap[y*m_regionWidth + x];
                }
            }

            // Resize using interpolation

            // This particular way is quick but it only works on a multiple of the original

            // The idea behind this method can be described with the following diagrams
            // second pass and third pass happen in the same loop really..  just separated
            // them to show what this does.

            // First Pass
            // ResultArr:
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1
            // 1,1,1,1,1,1

            // Second Pass
            // ResultArr2:
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,
            // ,,,,,,,,,,
            // 1,,1,,1,,1,,1,,1,

            // Third pass fills in the blanks
            // ResultArr2:
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1
            // 1,1,1,1,1,1,1,1,1,1,1,1

            // X,Y = .
            // X+1,y = ^
            // X,Y+1 = *
            // X+1,Y+1 = #

            // Filling in like this;
            // .*
            // ^#
            // 1st .
            // 2nd *
            // 3rd ^
            // 4th #
            // on single loop.

            float[,] resultarr2 = new float[512,512];
            for (int y = 0; y < m_regionHeight; y++)
            {
                for (int x = 0; x < m_regionWidth; x++)
                {
                    resultarr2[y*2, x*2] = resultarr[y, x];

                    if (y < m_regionHeight)
                    {
                        if (y + 1 < m_regionHeight)
                        {
                            if (x + 1 < m_regionWidth)
                            {
                                resultarr2[(y*2) + 1, x*2] = ((resultarr[y, x] + resultarr[y + 1, x] +
                                                               resultarr[y, x + 1] + resultarr[y + 1, x + 1])/4);
                            }
                            else
                            {
                                resultarr2[(y*2) + 1, x*2] = ((resultarr[y, x] + resultarr[y + 1, x])/2);
                            }
                        }
                        else
                        {
                            resultarr2[(y*2) + 1, x*2] = resultarr[y, x];
                        }
                    }
                    if (x < m_regionWidth)
                    {
                        if (x + 1 < m_regionWidth)
                        {
                            if (y + 1 < m_regionHeight)
                            {
                                resultarr2[y*2, (x*2) + 1] = ((resultarr[y, x] + resultarr[y + 1, x] +
                                                               resultarr[y, x + 1] + resultarr[y + 1, x + 1])/4);
                            }
                            else
                            {
                                resultarr2[y*2, (x*2) + 1] = ((resultarr[y, x] + resultarr[y, x + 1])/2);
                            }
                        }
                        else
                        {
                            resultarr2[y*2, (x*2) + 1] = resultarr[y, x];
                        }
                    }
                    if (x < m_regionWidth && y < m_regionHeight)
                    {
                        if ((x + 1 < m_regionWidth) && (y + 1 < m_regionHeight))
                        {
                            resultarr2[(y*2) + 1, (x*2) + 1] = ((resultarr[y, x] + resultarr[y + 1, x] +
                                                                 resultarr[y, x + 1] + resultarr[y + 1, x + 1])/4);
                        }
                        else
                        {
                            resultarr2[(y*2) + 1, (x*2) + 1] = resultarr[y, x];
                        }
                    }
                }
            }
            //Flatten out the array
            int i = 0;
            for (int y = 0; y < 512; y++)
            {
                for (int x = 0; x < 512; x++)
                {
                    if (Single.IsNaN(resultarr2[y, x]) || Single.IsInfinity(resultarr2[y, x]))
                    {
                        m_log.Warn("[PHYSICS]: Non finite heightfield element detected.  Setting it to 0");
                        resultarr2[y, x] = 0;
                    }
                    returnarr[i] = resultarr2[y, x];
                    i++;
                }
            }

            return returnarr;
        }

        #endregion

        public override void SetTerrain(float[] heightMap)
        {
            // this._heightmap[i] = (double)heightMap[i];
            // dbm (danx0r) -- creating a buffer zone of one extra sample all around
            _origheightmap = heightMap;    // Used for Fly height. Kitto Flora
            const uint heightmapWidth = m_regionWidth + 2;
            const uint heightmapHeight = m_regionHeight + 2;
            const uint heightmapWidthSamples = 2*m_regionWidth + 2;
            const uint heightmapHeightSamples = 2*m_regionHeight + 2;
            const float scale = 1.0f;
            const float offset = 0.0f;
            const float thickness = 0.2f;
            const int wrap = 0;

            //Double resolution
            heightMap = ResizeTerrain512Interpolation(heightMap);
            float hfmin = 2000;
            float hfmax = -2000;
            for (int x = 0; x < heightmapWidthSamples; x++)
            {
                for (int y = 0; y < heightmapHeightSamples; y++)
                {
                    int xx = Util.Clip(x - 1, 0, 511);
                    int yy = Util.Clip(y - 1, 0, 511);

                    float val = heightMap[yy*512 + xx];
                    _heightmap[x*heightmapHeightSamples + y] = val;
                    hfmin = (val < hfmin) ? val : hfmin;
                    hfmax = (val > hfmax) ? val : hfmax;
                }
            }

            lock (OdeLock)
            {
                if (LandGeom != IntPtr.Zero)
                {
                    d.SpaceRemove(space, LandGeom);
                }
                IntPtr HeightmapData = d.GeomHeightfieldDataCreate();
                d.GeomHeightfieldDataBuildSingle(HeightmapData, _heightmap, 0, heightmapWidth, heightmapHeight,
                                                 (int) heightmapWidthSamples, (int) heightmapHeightSamples, scale,
                                                 offset, thickness, wrap);
                d.GeomHeightfieldDataSetBounds(HeightmapData, hfmin - 1 , hfmax + 1 );
                LandGeom = d.CreateHeightfield(space, HeightmapData, 1);
                if (LandGeom != IntPtr.Zero)
                {
                    d.GeomSetCategoryBits(LandGeom, (int)(CollisionCategories.Land));
                    d.GeomSetCollideBits(LandGeom, (int)(CollisionCategories.Space));

                }
                geom_name_map[LandGeom] = "Terrain";

                d.Matrix3 R = new d.Matrix3();

                Quaternion q1 = Quaternion.CreateFromAxisAngle(new Vector3(1, 0, 0), 1.5707f);
                Quaternion q2 = Quaternion.CreateFromAxisAngle(new Vector3(0, 1, 0), 1.5707f);
                //Axiom.Math.Quaternion q3 = Axiom.Math.Quaternion.FromAngleAxis(3.14f, new Axiom.Math.Vector3(0, 0, 1));

                q1 = q1*q2;
                //q1 = q1 * q3;
                Vector3 v3;
                float angle;
                q1.GetAxisAngle(out v3, out angle);

                d.RFromAxisAndAngle(out R, v3.X, v3.Y, v3.Z, angle);
                d.GeomSetRotation(LandGeom, ref R);
                d.GeomSetPosition(LandGeom, 128, 128, 0);
            }
        }

        public override void DeleteTerrain()
        {
        }

        public float GetWaterLevel()
        {
            return waterlevel;
        }

        public override void SetWaterLevel(float baseheight)
        {
            waterlevel = baseheight;
            randomizeWater(waterlevel);
        }

        public void randomizeWater(float baseheight)
        {
            const uint heightmapWidth = m_regionWidth + 2;
            const uint heightmapHeight = m_regionHeight + 2;
            const uint heightmapWidthSamples = m_regionWidth + 2;
            const uint heightmapHeightSamples = m_regionHeight + 2;
            const float scale = 1.0f;
            const float offset = 0.0f;
            const float thickness = 2.9f;
            const int wrap = 0;

            for (int i = 0; i < (258 * 258); i++)
            {
                _watermap[i] = (baseheight-0.1f) + ((float)fluidRandomizer.Next(1,9) / 10f);
               // m_log.Info((baseheight - 0.1f) + ((float)fluidRandomizer.Next(1, 9) / 10f));
            }

            lock (OdeLock)
            {
                if (WaterGeom != IntPtr.Zero)
                {
                    d.SpaceRemove(space, WaterGeom);
                }
                IntPtr HeightmapData = d.GeomHeightfieldDataCreate();
                d.GeomHeightfieldDataBuildSingle(HeightmapData, _watermap, 0, heightmapWidth, heightmapHeight,
                                                 (int)heightmapWidthSamples, (int)heightmapHeightSamples, scale,
                                                 offset, thickness, wrap);
                d.GeomHeightfieldDataSetBounds(HeightmapData, m_regionWidth, m_regionHeight);
                WaterGeom = d.CreateHeightfield(space, HeightmapData, 1);
                if (WaterGeom != IntPtr.Zero)
                {
                    d.GeomSetCategoryBits(WaterGeom, (int)(CollisionCategories.Water));
                    d.GeomSetCollideBits(WaterGeom, (int)(CollisionCategories.Space));

                }
                geom_name_map[WaterGeom] = "Water";

                d.Matrix3 R = new d.Matrix3();

                Quaternion q1 = Quaternion.CreateFromAxisAngle(new Vector3(1, 0, 0), 1.5707f);
                Quaternion q2 = Quaternion.CreateFromAxisAngle(new Vector3(0, 1, 0), 1.5707f);
                //Axiom.Math.Quaternion q3 = Axiom.Math.Quaternion.FromAngleAxis(3.14f, new Axiom.Math.Vector3(0, 0, 1));

                q1 = q1 * q2;
                //q1 = q1 * q3;
                Vector3 v3;
                float angle;
                q1.GetAxisAngle(out v3, out angle);

                d.RFromAxisAndAngle(out R, v3.X, v3.Y, v3.Z, angle);
                d.GeomSetRotation(WaterGeom, ref R);
                d.GeomSetPosition(WaterGeom, 128, 128, 0);
                
            }

        }

        public override void Dispose()
        {
            lock (OdeLock)
            {
                lock (_prims)
                {
                    foreach (OdePrim prm in _prims)
                    {
                        RemovePrim(prm);
                    }
                }

                //foreach (OdeCharacter act in _characters)
                //{
                    //RemoveAvatar(act);
                //}
                d.WorldDestroy(world);
                //d.CloseODE();
            }
        }
        public override Dictionary<uint, float> GetTopColliders()
        {
            Dictionary<uint, float> returncolliders = new Dictionary<uint, float>();
            int cnt = 0;
            lock (_prims)
            {
                foreach (OdePrim prm in _prims)
                {
                    if (prm.CollisionScore > 0)
                    {
                        returncolliders.Add(prm.m_localID, prm.CollisionScore);
                        cnt++;
                        prm.CollisionScore = 0f;
                        if (cnt > 25)
                        {
                            break;
                        }
                    }
                }
            }
            return returncolliders;
        }
#if USE_DRAWSTUFF
        // Keyboard callback
        public void command(int cmd)
        {
            IntPtr geom;
            d.Mass mass;
            d.Vector3 sides = new d.Vector3(d.RandReal() * 0.5f + 0.1f, d.RandReal() * 0.5f + 0.1f, d.RandReal() * 0.5f + 0.1f);

            

            Char ch = Char.ToLower((Char)cmd);
            switch ((Char)ch)
            {
                case 'w':
                    try
                    {
                        Vector3 rotate = (new Vector3(1, 0, 0) * Quaternion.CreateFromEulers(hpr.Z * Utils.DEG_TO_RAD, hpr.Y * Utils.DEG_TO_RAD, hpr.X * Utils.DEG_TO_RAD));

                        xyz.X += rotate.X; xyz.Y += rotate.Y; xyz.Z += rotate.Z;
                        ds.SetViewpoint(ref xyz, ref hpr);
                    }
                    catch (ArgumentException)
                    { hpr.X = 0; }
                    break;

                case 'a':
                    hpr.X++;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;

                case 's':
                    try
                    {
                        Vector3 rotate2 = (new Vector3(-1, 0, 0) * Quaternion.CreateFromEulers(hpr.Z * Utils.DEG_TO_RAD, hpr.Y * Utils.DEG_TO_RAD, hpr.X * Utils.DEG_TO_RAD));

                        xyz.X += rotate2.X; xyz.Y += rotate2.Y; xyz.Z += rotate2.Z;
                        ds.SetViewpoint(ref xyz, ref hpr);
                    }
                    catch (ArgumentException)
                    { hpr.X = 0; }
                    break;
                case 'd':
                    hpr.X--;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;
                case 'r':
                    xyz.Z++;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;
                case 'f':
                    xyz.Z--;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;
                case 'e':
                    xyz.Y++;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;
                case 'q':
                    xyz.Y--;
                    ds.SetViewpoint(ref xyz, ref hpr);
                    break;
            }
        }

        public void step(int pause)
        {
            
            ds.SetColor(1.0f, 1.0f, 0.0f);
            ds.SetTexture(ds.Texture.Wood);
            lock (_prims)
            {
                foreach (OdePrim prm in _prims)
                {
                    //IntPtr body = d.GeomGetBody(prm.prim_geom);
                    if (prm.prim_geom != IntPtr.Zero)
                    {
                        d.Vector3 pos;
                        d.GeomCopyPosition(prm.prim_geom, out pos);
                        //d.BodyCopyPosition(body, out pos);

                        d.Matrix3 R;
                        d.GeomCopyRotation(prm.prim_geom, out R);
                        //d.BodyCopyRotation(body, out R);


                        d.Vector3 sides = new d.Vector3();
                        sides.X = prm.Size.X;
                        sides.Y = prm.Size.Y;
                        sides.Z = prm.Size.Z;

                        ds.DrawBox(ref pos, ref R, ref sides);
                    }
                }
            }
            ds.SetColor(1.0f, 0.0f, 0.0f);
            lock (_characters)
            {
                foreach (OdeCharacter chr in _characters)
                {
                    if (chr.Shell != IntPtr.Zero)
                    {
                        IntPtr body = d.GeomGetBody(chr.Shell);

                        d.Vector3 pos;
                        d.GeomCopyPosition(chr.Shell, out pos);
                        //d.BodyCopyPosition(body, out pos);

                        d.Matrix3 R;
                        d.GeomCopyRotation(chr.Shell, out R);
                        //d.BodyCopyRotation(body, out R);

                        ds.DrawCapsule(ref pos, ref R, chr.Size.Z, 0.35f);
                        d.Vector3 sides = new d.Vector3();
                        sides.X = 0.5f;
                        sides.Y = 0.5f;
                        sides.Z = 0.5f;

                        ds.DrawBox(ref pos, ref R, ref sides);


                    }
                }
            }
        }

        public void start(int unused)
        {
            
            ds.SetViewpoint(ref xyz, ref hpr);
        }
#endif
    }
}