Universe.Physics.OpenDynamicsEngine.ODEPhysicsScene.Collision_optimized C# (CSharp) Method

        void Collision_optimized(float timeStep)
        {
            lock(_contactcountLock)
                m_global_contactcount = 0;
            //Clear out all the colliding attributes before we begin to collide anyone
            foreach (ODECharacter chr in _characters)
            {
                chr.IsColliding = false;
                chr.IsTruelyColliding = false;
            }
            List<IntPtr> shells = _characters.Where(chr => chr != null && chr.Shell != IntPtr.Zero && chr.Body != IntPtr.Zero).Select<ODECharacter, IntPtr>(chr => chr.Shell).ToList();
                
            lock (_activeprimsLock)
            {
                List<ODEPrim> removeprims = null;
                foreach (ODEPrim chr in _activeprims)
                {
                    //Fix colliding atributes!
                    chr.IsColliding = false;
                    chr.LinkSetIsColliding = false;
                }
                if (space != IntPtr.Zero)
                {
                    List<ODEPrim> primsToCollide = new List<ODEPrim>(_activeprims.Where(
                        prm => prm != null && prm.Body != IntPtr.Zero && d.BodyIsEnabled(prm.Body) && 
                            !prm.m_disabled && !prm.m_frozen && prm.prim_geom != IntPtr.Zero));
                    shells.AddRange(primsToCollide.ConvertAll<IntPtr>(prm => prm.prim_geom));
                    
                    
                    foreach (IntPtr shell in shells)
                    {
                        try
                        {
                            if (ContinueCollisionProcessing)
                                d.SpaceCollide2(space, shell, IntPtr.Zero, nearCallback);
                            else
                            {
                                //Do a step so that we can do the rest of the contacts, since
                                //  otherwise, we get prim explosions inworld
                                lock(_contactcountLock)
                                    m_global_contactcount = 0;
                                d.WorldQuickStep(world, ODE_STEPSIZE);
                                d.JointGroupEmpty(contactgroup);

                                d.SpaceCollide2(space, shell, IntPtr.Zero, nearCallback);
                            }
                        }
                        catch (AccessViolationException)
                        {
                            MainConsole.Instance.Warn("[ODE Physics]: Unable to space collide");
                        }
                    }

                    /*if (shells.Count > 0)
                    {
                        List<UnmanagedODE.ContactGeom> contacts = UnmanagedODE.UnmanagedODEPhysics.CollisionLoop(space, shells);
                    }*/

                    foreach (ODEPrim prm in
                        _activeprims.Where(prm => prm != null && (prm.m_frozen || prm.prim_geom == IntPtr.Zero)))
                    {
                        if (removeprims == null)
                            removeprims = new List<ODEPrim>();
                        removeprims.Add(prm);
                        if (prm.prim_geom == IntPtr.Zero)
                            MainConsole.Instance.Debug("[ODE 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!");
                    }
                    if (removeprims != null)
                    {
                        foreach (ODEPrim chr in removeprims)
                            _activeprims.Remove(chr);
                    }
                }
            }

            if (m_filterCollisions)
                _perloopContact.Clear();
        }