Merge branch 'master' into careminster

1 files changed, 954 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSNPlugin/BSScene.cs b/OpenSim/Region/Physics/BulletSNPlugin/BSScene.cs
new file mode 100644
index 0000000..6bcea3f
--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSNPlugin/BSScene.cs
@@ -0,0 +1,954 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyrightD
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading;
+using OpenSim.Framework;
+using OpenSim.Region.Framework;
+using OpenSim.Region.CoreModules;
+using Logging = OpenSim.Region.CoreModules.Framework.Statistics.Logging;
+using OpenSim.Region.Physics.Manager;
+using Nini.Config;
+using log4net;
+using OpenMetaverse;
+
+// TODOs for BulletSim (for BSScene, BSPrim, BSCharacter and BulletSim)
+// Based on material, set density and friction
+// More efficient memory usage when passing hull information from BSPrim to BulletSim
+// Do attachments need to be handled separately? Need collision events. Do not collide with VolumeDetect
+// Implement LockAngularMotion
+// Add PID movement operations. What does ScenePresence.MoveToTarget do?
+// Check terrain size. 128 or 127?
+// Raycast
+//
+namespace OpenSim.Region.Physics.BulletSNPlugin
+{
+public sealed class BSScene : PhysicsScene, IPhysicsParameters
+{
+    private static readonly ILog m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
+    private static readonly string LogHeader = "[BULLETS SCENE]";
+
+    // The name of the region we're working for.
+    public string RegionName { get; private set; }
+
+    public string BulletSimVersion = "?";
+
+    public Dictionary<uint, BSPhysObject> PhysObjects;
+    public BSShapeCollection Shapes;
+
+    // Keeping track of the objects with collisions so we can report begin and end of a collision
+    public HashSet<BSPhysObject> ObjectsWithCollisions = new HashSet<BSPhysObject>();
+    public HashSet<BSPhysObject> ObjectsWithNoMoreCollisions = new HashSet<BSPhysObject>();
+    // Keep track of all the avatars so we can send them a collision event
+    //    every tick so OpenSim will update its animation.
+    private HashSet<BSPhysObject> m_avatars = new HashSet<BSPhysObject>();
+
+    // let my minuions use my logger
+    public ILog Logger { get { return m_log; } }
+
+    public IMesher mesher;
+    public uint WorldID { get; private set; }
+    public BulletSim World { get; private set; }
+
+    // All the constraints that have been allocated in this instance.
+    public BSConstraintCollection Constraints { get; private set; }
+
+    // Simulation parameters
+    internal int m_maxSubSteps;
+    internal float m_fixedTimeStep;
+    internal long m_simulationStep = 0;
+    public long SimulationStep { get { return m_simulationStep; } }
+    internal int m_taintsToProcessPerStep;
+    internal float LastTimeStep { get; private set; }
+
+    // Physical objects can register for prestep or poststep events
+    public delegate void PreStepAction(float timeStep);
+    public delegate void PostStepAction(float timeStep);
+    public event PreStepAction BeforeStep;
+    public event PreStepAction AfterStep;
+
+    // A value of the time now so all the collision and update routines do not have to get their own
+    // Set to 'now' just before all the prims and actors are called for collisions and updates
+    public int SimulationNowTime { get; private set; }
+
+    // True if initialized and ready to do simulation steps
+    private bool m_initialized = false;
+
+    // Flag which is true when processing taints.
+    // Not guaranteed to be correct all the time (don't depend on this) but good for debugging.
+    public bool InTaintTime { get; private set; }
+
+    // Pinned memory used to pass step information between managed and unmanaged
+    internal int m_maxCollisionsPerFrame;
+    private List<BulletXNA.CollisionDesc> m_collisionArray;
+    //private GCHandle m_collisionArrayPinnedHandle;
+
+    internal int m_maxUpdatesPerFrame;
+    private List<BulletXNA.EntityProperties> m_updateArray;
+    //private GCHandle m_updateArrayPinnedHandle;
+
+
+    public const uint TERRAIN_ID = 0;       // OpenSim senses terrain with a localID of zero
+    public const uint GROUNDPLANE_ID = 1;
+    public const uint CHILDTERRAIN_ID = 2;  // Terrain allocated based on our mega-prim childre start here
+
+    public float SimpleWaterLevel { get; set; }
+    public BSTerrainManager TerrainManager { get; private set; }
+
+    public ConfigurationParameters Params
+    {
+        get { return UnmanagedParams[0]; }
+    }
+    public Vector3 DefaultGravity
+    {
+        get { return new Vector3(0f, 0f, Params.gravity); }
+    }
+    // Just the Z value of the gravity
+    public float DefaultGravityZ
+    {
+        get { return Params.gravity; }
+    }
+
+    // When functions in the unmanaged code must be called, it is only
+    //   done at a known time just before the simulation step. The taint
+    //   system saves all these function calls and executes them in
+    //   order before the simulation.
+    public delegate void TaintCallback();
+    private struct TaintCallbackEntry
+    {
+        public String ident;
+        public TaintCallback callback;
+        public TaintCallbackEntry(string i, TaintCallback c)
+        {
+            ident = i;
+            callback = c;
+        }
+    }
+    private Object _taintLock = new Object();   // lock for using the next object
+    private List<TaintCallbackEntry> _taintOperations;
+    private Dictionary<string, TaintCallbackEntry> _postTaintOperations;
+    private List<TaintCallbackEntry> _postStepOperations;
+
+    // A pointer to an instance if this structure is passed to the C++ code
+    // Used to pass basic configuration values to the unmanaged code.
+    internal ConfigurationParameters[] UnmanagedParams;
+    //GCHandle m_paramsHandle;
+
+    // Handle to the callback used by the unmanaged code to call into the managed code.
+    // Used for debug logging.
+    // Need to store the handle in a persistant variable so it won't be freed.
+    private BulletSimAPI.DebugLogCallback m_DebugLogCallbackHandle;
+
+    // Sometimes you just have to log everything.
+    public Logging.LogWriter PhysicsLogging;
+    private bool m_physicsLoggingEnabled;
+    private string m_physicsLoggingDir;
+    private string m_physicsLoggingPrefix;
+    private int m_physicsLoggingFileMinutes;
+    private bool m_physicsLoggingDoFlush;
+    // 'true' of the vehicle code is to log lots of details
+    public bool VehicleLoggingEnabled { get; private set; }
+    public bool VehiclePhysicalLoggingEnabled { get; private set; }
+
+    #region Construction and Initialization
+    public BSScene(string identifier)
+    {
+        m_initialized = false;
+        // we are passed the name of the region we're working for.
+        RegionName = identifier;
+    }
+
+    public override void Initialise(IMesher meshmerizer, IConfigSource config)
+    {
+        mesher = meshmerizer;
+        _taintOperations = new List<TaintCallbackEntry>();
+        _postTaintOperations = new Dictionary<string, TaintCallbackEntry>();
+        _postStepOperations = new List<TaintCallbackEntry>();
+        PhysObjects = new Dictionary<uint, BSPhysObject>();
+        Shapes = new BSShapeCollection(this);
+
+        // Allocate pinned memory to pass parameters.
+        UnmanagedParams = new ConfigurationParameters[1];
+        //m_paramsHandle = GCHandle.Alloc(UnmanagedParams, GCHandleType.Pinned);
+
+        // Set default values for physics parameters plus any overrides from the ini file
+        GetInitialParameterValues(config);
+
+        // allocate more pinned memory close to the above in an attempt to get the memory all together
+        m_collisionArray = new List<BulletXNA.CollisionDesc>();
+        //m_collisionArrayPinnedHandle = GCHandle.Alloc(m_collisionArray, GCHandleType.Pinned);
+        m_updateArray = new List<BulletXNA.EntityProperties>();
+        //m_updateArrayPinnedHandle = GCHandle.Alloc(m_updateArray, GCHandleType.Pinned);
+
+        // Enable very detailed logging.
+        // By creating an empty logger when not logging, the log message invocation code
+        //     can be left in and every call doesn't have to check for null.
+        if (m_physicsLoggingEnabled)
+        {
+            PhysicsLogging = new Logging.LogWriter(m_physicsLoggingDir, m_physicsLoggingPrefix, m_physicsLoggingFileMinutes);
+            PhysicsLogging.ErrorLogger = m_log; // for DEBUG. Let's the logger output error messages.
+        }
+        else
+        {
+            PhysicsLogging = new Logging.LogWriter();
+        }
+
+        // If Debug logging level, enable logging from the unmanaged code
+        m_DebugLogCallbackHandle = null;
+        if (m_log.IsDebugEnabled || PhysicsLogging.Enabled)
+        {
+            m_log.DebugFormat("{0}: Initialize: Setting debug callback for unmanaged code", LogHeader);
+            if (PhysicsLogging.Enabled)
+                // The handle is saved in a variable to make sure it doesn't get freed after this call
+                m_DebugLogCallbackHandle = new BulletSimAPI.DebugLogCallback(BulletLoggerPhysLog);
+            else
+                m_DebugLogCallbackHandle = new BulletSimAPI.DebugLogCallback(BulletLogger);
+        }
+
+        // Get the version of the DLL
+        // TODO: this doesn't work yet. Something wrong with marshaling the returned string.
+        // BulletSimVersion = BulletSimAPI.GetVersion();
+        // m_log.WarnFormat("{0}: BulletSim.dll version='{1}'", LogHeader, BulletSimVersion);
+
+        // The bounding box for the simulated world. The origin is 0,0,0 unless we're
+        //    a child in a mega-region.
+        // Bullet actually doesn't care about the extents of the simulated
+        //    area. It tracks active objects no matter where they are.
+        Vector3 worldExtent = new Vector3(Constants.RegionSize, Constants.RegionSize, Constants.RegionHeight);
+
+        // m_log.DebugFormat("{0}: Initialize: Calling BulletSimAPI.Initialize.", LogHeader);
+
+        World = new BulletSim(0, this, BulletSimAPI.Initialize2(worldExtent, UnmanagedParams,
+                                        m_maxCollisionsPerFrame, ref m_collisionArray,
+                                        m_maxUpdatesPerFrame,ref m_updateArray,
+                                        m_DebugLogCallbackHandle));
+
+        Constraints = new BSConstraintCollection(World);
+
+        TerrainManager = new BSTerrainManager(this);
+        TerrainManager.CreateInitialGroundPlaneAndTerrain();
+
+        m_log.WarnFormat("{0} Linksets implemented with {1}", LogHeader, (BSLinkset.LinksetImplementation)BSParam.LinksetImplementation);
+
+        InTaintTime = false;
+        m_initialized = true;
+    }
+
+    // All default parameter values are set here. There should be no values set in the
+    // variable definitions.
+    private void GetInitialParameterValues(IConfigSource config)
+    {
+        ConfigurationParameters parms = new ConfigurationParameters();
+        UnmanagedParams[0] = parms;
+
+        BSParam.SetParameterDefaultValues(this);
+
+        if (config != null)
+        {
+            // If there are specifications in the ini file, use those values
+            IConfig pConfig = config.Configs["BulletSim"];
+            if (pConfig != null)
+            {
+                BSParam.SetParameterConfigurationValues(this, pConfig);
+
+                // Very detailed logging for physics debugging
+                m_physicsLoggingEnabled = pConfig.GetBoolean("PhysicsLoggingEnabled", false);
+                m_physicsLoggingDir = pConfig.GetString("PhysicsLoggingDir", ".");
+                m_physicsLoggingPrefix = pConfig.GetString("PhysicsLoggingPrefix", "physics-%REGIONNAME%-");
+                m_physicsLoggingFileMinutes = pConfig.GetInt("PhysicsLoggingFileMinutes", 5);
+                m_physicsLoggingDoFlush = pConfig.GetBoolean("PhysicsLoggingDoFlush", false);
+                // Very detailed logging for vehicle debugging
+                VehicleLoggingEnabled = pConfig.GetBoolean("VehicleLoggingEnabled", false);
+                VehiclePhysicalLoggingEnabled = pConfig.GetBoolean("VehiclePhysicalLoggingEnabled", false);
+
+                // Do any replacements in the parameters
+                m_physicsLoggingPrefix = m_physicsLoggingPrefix.Replace("%REGIONNAME%", RegionName);
+            }
+
+            // The material characteristics.
+            BSMaterials.InitializeFromDefaults(Params);
+            if (pConfig != null)
+            {
+                // Let the user add new and interesting material property values.
+                BSMaterials.InitializefromParameters(pConfig);
+            }
+        }
+    }
+
+    // A helper function that handles a true/false parameter and returns the proper float number encoding
+    float ParamBoolean(IConfig config, string parmName, float deflt)
+    {
+        float ret = deflt;
+        if (config.Contains(parmName))
+        {
+            ret = ConfigurationParameters.numericFalse;
+            if (config.GetBoolean(parmName, false))
+            {
+                ret = ConfigurationParameters.numericTrue;
+            }
+        }
+        return ret;
+    }
+
+    // Called directly from unmanaged code so don't do much
+    private void BulletLogger(string msg)
+    {
+        m_log.Debug("[BULLETS UNMANAGED]:" + msg);
+    }
+
+    // Called directly from unmanaged code so don't do much
+    private void BulletLoggerPhysLog(string msg)
+    {
+        DetailLog("[BULLETS UNMANAGED]:" + msg);
+    }
+
+    public override void Dispose()
+    {
+        // m_log.DebugFormat("{0}: Dispose()", LogHeader);
+
+        // make sure no stepping happens while we're deleting stuff
+        m_initialized = false;
+
+        foreach (KeyValuePair<uint, BSPhysObject> kvp in PhysObjects)
+        {
+            kvp.Value.Destroy();
+        }
+        PhysObjects.Clear();
+
+        // Now that the prims are all cleaned up, there should be no constraints left
+        if (Constraints != null)
+        {
+            Constraints.Dispose();
+            Constraints = null;
+        }
+
+        if (Shapes != null)
+        {
+            Shapes.Dispose();
+            Shapes = null;
+        }
+
+        if (TerrainManager != null)
+        {
+            TerrainManager.ReleaseGroundPlaneAndTerrain();
+            TerrainManager.Dispose();
+            TerrainManager = null;
+        }
+
+        // Anything left in the unmanaged code should be cleaned out
+        BulletSimAPI.Shutdown2(World.ptr);
+
+        // Not logging any more
+        PhysicsLogging.Close();
+    }
+    #endregion // Construction and Initialization
+
+    #region Prim and Avatar addition and removal
+
+    public override PhysicsActor AddAvatar(string avName, Vector3 position, Vector3 size, bool isFlying)
+    {
+        m_log.ErrorFormat("{0}: CALL TO AddAvatar in BSScene. NOT IMPLEMENTED", LogHeader);
+        return null;
+    }
+
+    public override PhysicsActor AddAvatar(uint localID, string avName, Vector3 position, Vector3 size, bool isFlying)
+    {
+        // m_log.DebugFormat("{0}: AddAvatar: {1}", LogHeader, avName);
+
+        if (!m_initialized) return null;
+
+        BSCharacter actor = new BSCharacter(localID, avName, this, position, size, isFlying);
+        lock (PhysObjects) PhysObjects.Add(localID, actor);
+
+        // TODO: Remove kludge someday.
+        // We must generate a collision for avatars whether they collide or not.
+        // This is required by OpenSim to update avatar animations, etc.
+        lock (m_avatars) m_avatars.Add(actor);
+
+        return actor;
+    }
+
+    public override void RemoveAvatar(PhysicsActor actor)
+    {
+        // m_log.DebugFormat("{0}: RemoveAvatar", LogHeader);
+
+        if (!m_initialized) return;
+
+        BSCharacter bsactor = actor as BSCharacter;
+        if (bsactor != null)
+        {
+            try
+            {
+                lock (PhysObjects) PhysObjects.Remove(actor.LocalID);
+                // Remove kludge someday
+                lock (m_avatars) m_avatars.Remove(bsactor);
+            }
+            catch (Exception e)
+            {
+                m_log.WarnFormat("{0}: Attempt to remove avatar that is not in physics scene: {1}", LogHeader, e);
+            }
+            bsactor.Destroy();
+            // bsactor.dispose();
+        }
+    }
+
+    public override void RemovePrim(PhysicsActor prim)
+    {
+        if (!m_initialized) return;
+
+        BSPrim bsprim = prim as BSPrim;
+        if (bsprim != null)
+        {
+            DetailLog("{0},RemovePrim,call", bsprim.LocalID);
+            // m_log.DebugFormat("{0}: RemovePrim. id={1}/{2}", LogHeader, bsprim.Name, bsprim.LocalID);
+            try
+            {
+                lock (PhysObjects) PhysObjects.Remove(bsprim.LocalID);
+            }
+            catch (Exception e)
+            {
+                m_log.ErrorFormat("{0}: Attempt to remove prim that is not in physics scene: {1}", LogHeader, e);
+            }
+            bsprim.Destroy();
+            // bsprim.dispose();
+        }
+        else
+        {
+            m_log.ErrorFormat("{0}: Attempt to remove prim that is not a BSPrim type.", LogHeader);
+        }
+    }
+
+    public override PhysicsActor AddPrimShape(string primName, PrimitiveBaseShape pbs, Vector3 position,
+                                              Vector3 size, Quaternion rotation, bool isPhysical, uint localID)
+    {
+        // m_log.DebugFormat("{0}: AddPrimShape2: {1}", LogHeader, primName);
+
+        if (!m_initialized) return null;
+
+        DetailLog("{0},AddPrimShape,call", localID);
+
+        BSPrim prim = new BSPrim(localID, primName, this, position, size, rotation, pbs, isPhysical);
+        lock (PhysObjects) PhysObjects.Add(localID, prim);
+        return prim;
+    }
+
+    // This is a call from the simulator saying that some physical property has been updated.
+    // The BulletSim driver senses the changing of relevant properties so this taint
+    // information call is not needed.
+    public override void AddPhysicsActorTaint(PhysicsActor prim) { }
+
+    #endregion // Prim and Avatar addition and removal
+
+    #region Simulation
+    // Simulate one timestep
+    public override float Simulate(float timeStep)
+    {
+        // prevent simulation until we've been initialized
+        if (!m_initialized) return 5.0f;
+
+        LastTimeStep = timeStep;
+
+        int updatedEntityCount = 0;
+        //Object updatedEntitiesPtr;
+        int collidersCount = 0;
+        //Object collidersPtr;
+
+        int beforeTime = 0;
+        int simTime = 0;
+
+        // update the prim states while we know the physics engine is not busy
+        int numTaints = _taintOperations.Count;
+
+        InTaintTime = true; // Only used for debugging so locking is not necessary.
+
+        ProcessTaints();
+
+        // Some of the physical objects requre individual, pre-step calls
+        TriggerPreStepEvent(timeStep);
+
+        // the prestep actions might have added taints
+        ProcessTaints();
+
+        InTaintTime = false; // Only used for debugging so locking is not necessary.
+
+        // step the physical world one interval
+        m_simulationStep++;
+        int numSubSteps = 0;
+
+        try
+        {
+            //if (VehicleLoggingEnabled) DumpVehicles();  // DEBUG
+            if (PhysicsLogging.Enabled) beforeTime = Util.EnvironmentTickCount();
+
+            numSubSteps = BulletSimAPI.PhysicsStep2(World.ptr, timeStep, m_maxSubSteps, m_fixedTimeStep,
+                        out updatedEntityCount, out m_updateArray, out collidersCount, out m_collisionArray);
+
+            if (PhysicsLogging.Enabled) simTime = Util.EnvironmentTickCountSubtract(beforeTime);
+            DetailLog("{0},Simulate,call, frame={1}, nTaints={2}, simTime={3}, substeps={4}, updates={5}, colliders={6}, objWColl={7}",
+                                    DetailLogZero, m_simulationStep, numTaints, simTime, numSubSteps, 
+                                    updatedEntityCount, collidersCount, ObjectsWithCollisions.Count);
+        }
+        catch (Exception e)
+        {
+            m_log.WarnFormat("{0},PhysicsStep Exception: nTaints={1}, substeps={2}, updates={3}, colliders={4}, e={5}",
+                        LogHeader, numTaints, numSubSteps, updatedEntityCount, collidersCount, e);
+            DetailLog("{0},PhysicsStepException,call, nTaints={1}, substeps={2}, updates={3}, colliders={4}",
+                        DetailLogZero, numTaints, numSubSteps, updatedEntityCount, collidersCount);
+            updatedEntityCount = 0;
+            collidersCount = 0;
+        }
+
+        // Don't have to use the pointers passed back since we know it is the same pinned memory we passed in.
+
+        // Get a value for 'now' so all the collision and update routines don't have to get their own.
+        SimulationNowTime = Util.EnvironmentTickCount();
+
+        // If there were collisions, process them by sending the event to the prim.
+        // Collisions must be processed before updates.
+        if (collidersCount > 0)
+        {
+            for (int ii = 0; ii < collidersCount; ii++)
+            {
+                uint cA = m_collisionArray[ii].aID;
+                uint cB = m_collisionArray[ii].bID;
+                Vector3 point = new Vector3(m_collisionArray[ii].point.X, m_collisionArray[ii].point.Y,
+                                            m_collisionArray[ii].point.Z);
+                Vector3 normal = new Vector3(m_collisionArray[ii].normal.X, m_collisionArray[ii].normal.Y,
+                                            m_collisionArray[ii].normal.Z); 
+                SendCollision(cA, cB, point, normal, 0.01f);
+                SendCollision(cB, cA, point, -normal, 0.01f);
+            }
+        }
+
+        // The above SendCollision's batch up the collisions on the objects.
+        //      Now push the collisions into the simulator.
+        if (ObjectsWithCollisions.Count > 0)
+        {
+            foreach (BSPhysObject bsp in ObjectsWithCollisions)
+                if (!bsp.SendCollisions())
+                {
+                    // If the object is done colliding, see that it's removed from the colliding list
+                    ObjectsWithNoMoreCollisions.Add(bsp);
+                }
+        }
+
+        // This is a kludge to get avatar movement updates.
+        // The simulator expects collisions for avatars even if there are have been no collisions.
+        //    The event updates avatar animations and stuff.
+        // If you fix avatar animation updates, remove this overhead and let normal collision processing happen.
+        foreach (BSPhysObject bsp in m_avatars)
+            if (!ObjectsWithCollisions.Contains(bsp))   // don't call avatars twice
+                bsp.SendCollisions();
+
+        // Objects that are done colliding are removed from the ObjectsWithCollisions list.
+        // Not done above because it is inside an iteration of ObjectWithCollisions.
+        // This complex collision processing is required to create an empty collision
+        //     event call after all collisions have happened on an object. This enables
+        //     the simulator to generate the 'collision end' event.
+        if (ObjectsWithNoMoreCollisions.Count > 0)
+        {
+            foreach (BSPhysObject po in ObjectsWithNoMoreCollisions)
+                ObjectsWithCollisions.Remove(po);
+            ObjectsWithNoMoreCollisions.Clear();
+        }
+        // Done with collisions.
+
+        // If any of the objects had updated properties, tell the object it has been changed by the physics engine
+        if (updatedEntityCount > 0)
+        {
+            for (int ii = 0; ii < updatedEntityCount; ii++)
+            {
+
+                BulletXNA.EntityProperties entprop = m_updateArray[ii];
+                BSPhysObject pobj;
+                if (PhysObjects.TryGetValue(entprop.ID, out pobj))
+                {
+                    EntityProperties prop = new EntityProperties()
+                                                {
+                                                    Acceleration = new Vector3(entprop.Acceleration.X, entprop.Acceleration.Y, entprop.Acceleration.Z),
+                                                    ID = entprop.ID,
+                                                    Position = new Vector3(entprop.Position.X,entprop.Position.Y,entprop.Position.Z),
+                                                    Rotation = new Quaternion(entprop.Rotation.X,entprop.Rotation.Y,entprop.Rotation.Z,entprop.Rotation.W),
+                                                    RotationalVelocity = new Vector3(entprop.AngularVelocity.X,entprop.AngularVelocity.Y,entprop.AngularVelocity.Z),
+                                                    Velocity = new Vector3(entprop.Velocity.X,entprop.Velocity.Y,entprop.Velocity.Z)
+                                                };
+                    //m_log.Debug(pobj.Name + ":" + prop.ToString() + "\n");
+                    pobj.UpdateProperties(prop);
+                }
+            }
+        }
+
+        TriggerPostStepEvent(timeStep);
+
+        // The following causes the unmanaged code to output ALL the values found in ALL the objects in the world.
+        // Only enable this in a limited test world with few objects.
+        // BulletSimAPI.DumpAllInfo2(World.ptr);    // DEBUG DEBUG DEBUG
+
+        // The physics engine returns the number of milliseconds it simulated this call.
+        // These are summed and normalized to one second and divided by 1000 to give the reported physics FPS.
+        // Multiply by 55 to give a nominal frame rate of 55.
+        return (float)numSubSteps * m_fixedTimeStep * 1000f * 55f;
+    }
+
+    // Something has collided
+    private void SendCollision(uint localID, uint collidingWith, Vector3 collidePoint, Vector3 collideNormal, float penetration)
+    {
+        if (localID <= TerrainManager.HighestTerrainID)
+        {
+            return;         // don't send collisions to the terrain
+        }
+
+        BSPhysObject collider;
+        if (!PhysObjects.TryGetValue(localID, out collider))
+        {
+            // If the object that is colliding cannot be found, just ignore the collision.
+            DetailLog("{0},BSScene.SendCollision,colliderNotInObjectList,id={1},with={2}", DetailLogZero, localID, collidingWith);
+            return;
+        }
+
+        // The terrain is not in the physical object list so 'collidee' can be null when Collide() is called.
+        BSPhysObject collidee = null;
+        PhysObjects.TryGetValue(collidingWith, out collidee);
+
+        // DetailLog("{0},BSScene.SendCollision,collide,id={1},with={2}", DetailLogZero, localID, collidingWith);
+
+        if (collider.Collide(collidingWith, collidee, collidePoint, collideNormal, penetration))
+        {
+            // If a collision was posted, remember to send it to the simulator
+            ObjectsWithCollisions.Add(collider);
+        }
+
+        return;
+    }
+
+    #endregion // Simulation
+
+    public override void GetResults() { }
+
+    #region Terrain
+
+    public override void SetTerrain(float[] heightMap) {
+        TerrainManager.SetTerrain(heightMap);
+    }
+
+    public override void SetWaterLevel(float baseheight)
+    {
+        SimpleWaterLevel = baseheight;
+    }
+
+    public override void DeleteTerrain()
+    {
+        // m_log.DebugFormat("{0}: DeleteTerrain()", LogHeader);
+    }
+
+    // Although no one seems to check this, I do support combining.
+    public override bool SupportsCombining()
+    {
+        return TerrainManager.SupportsCombining();
+    }
+    // This call says I am a child to region zero in a mega-region. 'pScene' is that
+    //    of region zero, 'offset' is my offset from regions zero's origin, and
+    //    'extents' is the largest XY that is handled in my region.
+    public override void Combine(PhysicsScene pScene, Vector3 offset, Vector3 extents)
+    {
+        TerrainManager.Combine(pScene, offset, extents);
+    }
+
+    // Unhook all the combining that I know about.
+    public override void UnCombine(PhysicsScene pScene)
+    {
+        TerrainManager.UnCombine(pScene);
+    }
+
+    #endregion // Terrain
+
+    public override Dictionary<uint, float> GetTopColliders()
+    {
+        return new Dictionary<uint, float>();
+    }
+
+    public override bool IsThreaded { get { return false;  } }
+
+    #region Taints
+    // The simulation execution order is:
+    // Simulate()
+    //    DoOneTimeTaints
+    //    TriggerPreStepEvent
+    //    DoOneTimeTaints
+    //    Step()
+    //       ProcessAndForwardCollisions
+    //       ProcessAndForwardPropertyUpdates
+    //    TriggerPostStepEvent
+
+    // Calls to the PhysicsActors can't directly call into the physics engine
+    //       because it might be busy. We delay changes to a known time.
+    // We rely on C#'s closure to save and restore the context for the delegate.
+    public void TaintedObject(String ident, TaintCallback callback)
+    {
+        if (!m_initialized) return;
+
+        lock (_taintLock)
+        {
+            _taintOperations.Add(new TaintCallbackEntry(ident, callback));
+        }
+
+        return;
+    }
+
+    // Sometimes a potentially tainted operation can be used in and out of taint time.
+    // This routine executes the command immediately if in taint-time otherwise it is queued.
+    public void TaintedObject(bool inTaintTime, string ident, TaintCallback callback)
+    {
+        if (inTaintTime)
+            callback();
+        else
+            TaintedObject(ident, callback);
+    }
+
+    private void TriggerPreStepEvent(float timeStep)
+    {
+        PreStepAction actions = BeforeStep;
+        if (actions != null)
+            actions(timeStep);
+
+    }
+
+    private void TriggerPostStepEvent(float timeStep)
+    {
+        PreStepAction actions = AfterStep;
+        if (actions != null)
+            actions(timeStep);
+
+    }
+
+    // When someone tries to change a property on a BSPrim or BSCharacter, the object queues
+    // a callback into itself to do the actual property change. That callback is called
+    // here just before the physics engine is called to step the simulation.
+    public void ProcessTaints()
+    {
+        ProcessRegularTaints();
+        ProcessPostTaintTaints();
+    }
+
+    private void ProcessRegularTaints()
+    {
+        if (_taintOperations.Count > 0)  // save allocating new list if there is nothing to process
+        {
+            // swizzle a new list into the list location so we can process what's there
+            List<TaintCallbackEntry> oldList;
+            lock (_taintLock)
+            {
+                oldList = _taintOperations;
+                _taintOperations = new List<TaintCallbackEntry>();
+            }
+
+            foreach (TaintCallbackEntry tcbe in oldList)
+            {
+                try
+                {
+                    DetailLog("{0},BSScene.ProcessTaints,doTaint,id={1}", DetailLogZero, tcbe.ident); // DEBUG DEBUG DEBUG
+                    tcbe.callback();
+                }
+                catch (Exception e)
+                {
+                    m_log.ErrorFormat("{0}: ProcessTaints: {1}: Exception: {2}", LogHeader, tcbe.ident, e);
+                }
+            }
+            oldList.Clear();
+        }
+    }
+
+    // Schedule an update to happen after all the regular taints are processed.
+    // Note that new requests for the same operation ("ident") for the same object ("ID")
+    //     will replace any previous operation by the same object.
+    public void PostTaintObject(String ident, uint ID, TaintCallback callback)
+    {
+        string uniqueIdent = ident + "-" + ID.ToString();
+        lock (_taintLock)
+        {
+            _postTaintOperations[uniqueIdent] = new TaintCallbackEntry(uniqueIdent, callback);
+        }
+
+        return;
+    }
+
+    // Taints that happen after the normal taint processing but before the simulation step.
+    private void ProcessPostTaintTaints()
+    {
+        if (_postTaintOperations.Count > 0)
+        {
+            Dictionary<string, TaintCallbackEntry> oldList;
+            lock (_taintLock)
+            {
+                oldList = _postTaintOperations;
+                _postTaintOperations = new Dictionary<string, TaintCallbackEntry>();
+            }
+
+            foreach (KeyValuePair<string,TaintCallbackEntry> kvp in oldList)
+            {
+                try
+                {
+                    DetailLog("{0},BSScene.ProcessPostTaintTaints,doTaint,id={1}", DetailLogZero, kvp.Key); // DEBUG DEBUG DEBUG
+                    kvp.Value.callback();
+                }
+                catch (Exception e)
+                {
+                    m_log.ErrorFormat("{0}: ProcessPostTaintTaints: {1}: Exception: {2}", LogHeader, kvp.Key, e);
+                }
+            }
+            oldList.Clear();
+        }
+    }
+
+    // Only used for debugging. Does not change state of anything so locking is not necessary.
+    public bool AssertInTaintTime(string whereFrom)
+    {
+        if (!InTaintTime)
+        {
+            DetailLog("{0},BSScene.AssertInTaintTime,NOT IN TAINT TIME,Region={1},Where={2}", DetailLogZero, RegionName, whereFrom);
+            m_log.ErrorFormat("{0} NOT IN TAINT TIME!! Region={1}, Where={2}", LogHeader, RegionName, whereFrom);
+            Util.PrintCallStack();  // Prints the stack into the DEBUG log file.
+        }
+        return InTaintTime;
+    }
+
+    #endregion // Taints
+
+    #region INI and command line parameter processing
+
+    #region IPhysicsParameters
+    // Get the list of parameters this physics engine supports
+    public PhysParameterEntry[] GetParameterList()
+    {
+        BSParam.BuildParameterTable();
+        return BSParam.SettableParameters;
+    }
+
+    // Set parameter on a specific or all instances.
+    // Return 'false' if not able to set the parameter.
+    // Setting the value in the m_params block will change the value the physics engine
+    //   will use the next time since it's pinned and shared memory.
+    // Some of the values require calling into the physics engine to get the new
+    //   value activated ('terrainFriction' for instance).
+    public bool SetPhysicsParameter(string parm, float val, uint localID)
+    {
+        bool ret = false;
+        BSParam.ParameterDefn theParam;
+        if (BSParam.TryGetParameter(parm, out theParam))
+        {
+            theParam.setter(this, parm, localID, val);
+            ret = true;
+        }
+        return ret;
+    }
+
+    // update all the localIDs specified
+    // If the local ID is APPLY_TO_NONE, just change the default value
+    // If the localID is APPLY_TO_ALL change the default value and apply the new value to all the lIDs
+    // If the localID is a specific object, apply the parameter change to only that object
+    internal delegate void AssignVal(float x);
+    internal void UpdateParameterObject(AssignVal setDefault, string parm, uint localID, float val)
+    {
+        List<uint> objectIDs = new List<uint>();
+        switch (localID)
+        {
+            case PhysParameterEntry.APPLY_TO_NONE:
+                setDefault(val);            // setting only the default value
+                // This will cause a call into the physical world if some operation is specified (SetOnObject).
+                objectIDs.Add(TERRAIN_ID);
+                TaintedUpdateParameter(parm, objectIDs, val);
+                break;
+            case PhysParameterEntry.APPLY_TO_ALL:
+                setDefault(val);  // setting ALL also sets the default value
+                lock (PhysObjects) objectIDs = new List<uint>(PhysObjects.Keys);
+                TaintedUpdateParameter(parm, objectIDs, val);
+                break;
+            default:
+                // setting only one localID
+                objectIDs.Add(localID);
+                TaintedUpdateParameter(parm, objectIDs, val);
+                break;
+        }
+    }
+
+    // schedule the actual updating of the paramter to when the phys engine is not busy
+    private void TaintedUpdateParameter(string parm, List<uint> lIDs, float val)
+    {
+        float xval = val;
+        List<uint> xlIDs = lIDs;
+        string xparm = parm;
+        TaintedObject("BSScene.UpdateParameterSet", delegate() {
+            BSParam.ParameterDefn thisParam;
+            if (BSParam.TryGetParameter(xparm, out thisParam))
+            {
+                if (thisParam.onObject != null)
+                {
+                    foreach (uint lID in xlIDs)
+                    {
+                        BSPhysObject theObject = null;
+                        PhysObjects.TryGetValue(lID, out theObject);
+                        thisParam.onObject(this, theObject, xval);
+                    }
+                }
+            }
+        });
+    }
+
+    // Get parameter.
+    // Return 'false' if not able to get the parameter.
+    public bool GetPhysicsParameter(string parm, out float value)
+    {
+        float val = 0f;
+        bool ret = false;
+        BSParam.ParameterDefn theParam;
+        if (BSParam.TryGetParameter(parm, out theParam))
+        {
+            val = theParam.getter(this);
+            ret = true;
+        }
+        value = val;
+        return ret;
+    }
+
+    #endregion IPhysicsParameters
+
+    #endregion Runtime settable parameters
+
+    // Invoke the detailed logger and output something if it's enabled.
+    public void DetailLog(string msg, params Object[] args)
+    {
+        PhysicsLogging.Write(msg, args);
+        // Add the Flush() if debugging crashes. Gets all the messages written out.
+        if (m_physicsLoggingDoFlush) PhysicsLogging.Flush();
+    }
+    // Used to fill in the LocalID when there isn't one. It's the correct number of characters.
+    public const string DetailLogZero = "0000000000";
+
+}
+}