fCraft.Player.UpdateVisibleEntities C# (CSharp) Method

        private void UpdateVisibleEntities()
        {
            if ( World == null )
                PlayerOpException.ThrowNoWorld( this );
            if ( possessionPlayer != null ) {
                if ( !possessionPlayer.IsOnline || possessionPlayer.IsSpectating ) {
                    Message( "You have been released from possession" );
                    possessionPlayer = null;
                } else {
                    Position sendTo = possessionPlayer.Position;
                    World possessedWorld = possessionPlayer.World;
                    if ( possessedWorld == null ) {
                        throw new InvalidOperationException( "Possess: Something weird just happened (error 404)." );
                    }
                    if ( possessedWorld != World ) {
                        if ( CanJoin( possessedWorld ) ) {
                            postJoinPosition = sendTo;
                            Message( "Joined {0}&S (possessed)",
                                     possessedWorld.ClassyName );
                            JoinWorldNow( possessedWorld, false, WorldChangeReason.SpectateTargetJoined );
                        } else {
                            possessionPlayer.Message( "Stopped possessing {0}&S (they cannot join {1}&S)",
                                      ClassyName,
                                      possessedWorld.ClassyName );
                            possessionPlayer = null;
                        }
                    } else if ( sendTo != Position ) {
                        SendNow( PacketWriter.MakeSelfTeleport( sendTo ) );
                    }
                }
            }
            if ( spectatedPlayer != null ) {
                if ( !spectatedPlayer.IsOnline || !CanSee( spectatedPlayer ) ) {
                    Message( "Stopped spectating {0}&S (disconnected)", spectatedPlayer.ClassyName );
                    spectatedPlayer = null;
                } else {
                    Position spectatePos = spectatedPlayer.Position;
                    World spectateWorld = spectatedPlayer.World;
                    if ( spectateWorld == null ) {
                        throw new InvalidOperationException( "Trying to spectate player without a world." );
                    }
                    if ( spectateWorld != World ) {
                        if ( CanJoin( spectateWorld ) ) {
                            postJoinPosition = spectatePos;
                            Message( "Joined {0}&S to continue spectating {1}",
                                     spectateWorld.ClassyName,
                                     spectatedPlayer.ClassyName );
                            JoinWorldNow( spectateWorld, false, WorldChangeReason.SpectateTargetJoined );
                        } else {
                            Message( "Stopped spectating {0}&S (cannot join {1}&S)",
                                     spectatedPlayer.ClassyName,
                                     spectateWorld.ClassyName );
                            spectatedPlayer = null;
                        }
                    } else if ( spectatePos != Position ) {
                        SendNow( PacketWriter.MakeSelfTeleport( spectatePos ) );
                    }
                }
            }

            Player[] worldPlayerList = World.Players;
            Position pos = Position;

            for ( int i = 0; i < worldPlayerList.Length; i++ ) {
                Player otherPlayer = worldPlayerList[i];
                if ( otherPlayer == this ||
                    !CanSeeMoving( otherPlayer ) ||
                    spectatedPlayer == otherPlayer || possessionPlayer != null )
                    continue;

                Position otherPos = otherPlayer.Position;
                int distance = pos.DistanceSquaredTo( otherPos );

                VisibleEntity entity;
                // if Player has a corresponding VisibleEntity
                if ( entities.TryGetValue( otherPlayer, out entity ) ) {
                    entity.MarkedForRetention = true;

                    if ( entity.LastKnownRank != otherPlayer.Info.Rank ) {
                        ReAddEntity( entity, otherPlayer, otherPos );
                        entity.LastKnownRank = otherPlayer.Info.Rank;
                    }
                    if ( otherPlayer.entityChanged ) {
                        ReAddEntity( entity, otherPlayer, otherPos );
                        otherPlayer.entityChanged = false;
                    } else if ( entity.Hidden ) {
                        if ( distance < entityShowingThreshold ) {
                            ShowEntity( entity, otherPos );
                        }
                    } else {
                        if ( distance > entityHidingThreshold ) {
                            HideEntity( entity );
                        } else if ( entity.LastKnownPosition != otherPos ) {
                            MoveEntity( entity, otherPos );
                        }
                    }
                } else {
                    AddEntity( otherPlayer, otherPos );
                }
            }

            // Find entities to remove (not marked for retention).
            foreach ( var pair in entities ) {
                if ( pair.Value.MarkedForRetention ) {
                    pair.Value.MarkedForRetention = false;
                } else {
                    playersToRemove.Push( pair.Key );
                }
            }

            // Remove non-retained entities
            while ( playersToRemove.Count > 0 ) {
                RemoveEntity( playersToRemove.Pop() );
            }

            fullUpdateCounter++;
            if ( fullUpdateCounter >= FullPositionUpdateInterval ) {
                fullUpdateCounter = 0;
            }
        }