nServerLag Class Reference

lag tracker on server More...

List of all members.

Public Member Functions
	nServerLag ()
REAL	Ping ()
REAL	Credit ()
void	Reset ()
void	SetClient (int client)
void	Report (REAL lag)
REAL	CreditLeft ()
REAL	TakeCredit (REAL lag)
Static Public Member Functions
static void	Balance ()
Private Attributes
REAL	creditUsed_
	the used lag credit
double	lastTime_
	the last time lag credit was calculated
double	lastLag_
	the last time lag was reported to the client
int	client_
	the client this object is responsible for

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Detailed Description

lag tracker on server

Definition at line 155 of file eLagCompensation.cpp.

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Constructor & Destructor Documentation

nServerLag::nServerLag

(

)

[inline]

Definition at line 158 of file eLagCompensation.cpp.

References Reset().

    {
        Reset();
    }

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Member Function Documentation

REAL nServerLag::Ping

(

)

[inline]

Definition at line 163 of file eLagCompensation.cpp.

References client_, nPingAverager::GetPing(), nConnectionInfo::ping, and sn_Connections.

Referenced by Report().

    {
        return sn_Connections[client_].ping.GetPing();
    }

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REAL nServerLag::Credit

(

)

[inline]

Definition at line 168 of file eLagCompensation.cpp.

References se_lagCredit.

Referenced by CreditLeft(), Report(), Reset(), and TakeCredit().

    {
        return se_lagCredit;
    }

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void nServerLag::Reset

(

)

[inline]

Definition at line 173 of file eLagCompensation.cpp.

References client_, Credit(), creditUsed_, lastLag_, lastTime_, se_lagCreditSweetSpot, and tSysTimeFloat().

Referenced by login_callback(), and nServerLag().

    {
        creditUsed_ = se_lagCreditSweetSpot * Credit();
        lastTime_ = lastLag_ = tSysTimeFloat();
        client_ = 0;
    }

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void nServerLag::SetClient

(

int

client

)

[inline]

Definition at line 180 of file eLagCompensation.cpp.

References client_, MAXCLIENTS, and tASSERT.

Referenced by login_callback().

    {
        tASSERT( 1 <= client && client <= MAXCLIENTS );

        client_ = client;
    }

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void nServerLag::Report

(

REAL

lag

)

[inline]

Definition at line 187 of file eLagCompensation.cpp.

References client_, Credit(), creditUsed_, EPS, lastLag_, Ping(), REAL, se_clientLagCompensation, se_lagCreditSingle, se_lagCreditSweetSpot, se_receiveLagMessageDescriptor, nMessage::Send(), nVersionFeature::Supported(), tNEW, tSysTimeFloat(), and weight.

Referenced by eLag::Report().

    {
        // see if it is useful to report
        if ( ! se_clientLagCompensation.Supported( client_ ) )
            return;

        // clamp
        lag = lag > se_lagCreditSingle ? se_lagCreditSingle : lag;

        // get info
        REAL credit = Credit();
        if ( credit < EPS )
            credit = EPS;
        REAL ping = Ping();

        // don't report too often
        double time = tSysTimeFloat();
        if ( time - lastLag_ < 4 * ping )
            return;
        lastLag_ = time;

        // send a simple message to the client
        nMessage * mess = tNEW( nMessage )( se_receiveLagMessageDescriptor );
        *mess << lag;

        // propose a weight to the client, it will determine how much impact the lag report has
        REAL weight = 1;
        if ( se_lagCreditSweetSpot > 0 )
        {
            weight = ( (creditUsed_+2*lag)/credit )/se_lagCreditSweetSpot;
        }
        *mess << weight;

        mess->Send( client_ );
    }

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REAL nServerLag::CreditLeft

(

)

[inline]

Definition at line 223 of file eLagCompensation.cpp.

References Credit(), and creditUsed_.

Referenced by eLag::Credit().

    {
        return Credit() - creditUsed_;
    }

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REAL nServerLag::TakeCredit

(

REAL

lag

)

[inline]

Definition at line 228 of file eLagCompensation.cpp.

References Balance(), con, Credit(), creditUsed_, dt, EPS, lastTime_, REAL, se_lagCreditSingle, se_lagCreditTime, se_lagThreshold, and tSysTimeFloat().

Referenced by eLag::TakeCredit().

    {
        lag -= se_lagThreshold;
        if ( lag > 0 )
        {
#ifdef DEBUG_LAG
            REAL lagBefore = lag;
#endif

            // if everyone is lagging, delete the used credit
            Balance();

            // clamp
            lag = lag > se_lagCreditSingle ? se_lagCreditSingle : lag;

            // get values
            REAL credit = Credit();

            // sanity check
            if ( se_lagCreditTime < EPS )
                se_lagCreditTime = EPS;

            // timestep credit
            double time = tSysTimeFloat();
            REAL dt = time - lastTime_;
            lastTime_ = time;
            creditUsed_ -= dt * credit/se_lagCreditTime;
            if ( creditUsed_ < 0 )
                creditUsed_ = 0;

            // see how much credit is left to be used
            REAL creditLeft = credit - creditUsed_;
            if ( lag > creditLeft )
                lag = creditLeft;
            if ( lag < 0 )
                lag = 0;

            // use it and return it
            creditUsed_ += lag;

#ifdef DEBUG_LAG
            {
                if ( lag > lagBefore )
                    con << "Requesting " << lagBefore << " seconds of lag credit, granting " << lag << ".\n";
                else
                    con << "Granting " << lag << " seconds of lag credit.\n";
            }
#endif

            lag += se_lagThreshold;

        }

        return lag;
    }

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void nServerLag::Balance

(

)

[static]

Definition at line 295 of file eLagCompensation.cpp.

References creditUsed_, MAXCLIENTS, REAL, se_lagCredit, se_lagCreditSweetSpot, sn_Connections, and sn_NumUsers().

Referenced by TakeCredit().

{
    int i;

    // only if many users are online
    if ( sn_NumUsers() <= 1 )
        return;

    // find the minimum used credit
    REAL minCredit = se_lagCredit;
    for ( i = MAXCLIENTS; i>0; --i )
    {
        if ( sn_Connections[i].socket )
        {
            REAL credit = se_serverLag[i].creditUsed_;
            if ( credit < minCredit )
                minCredit = credit;
        }
    }

    // find out how much you can take away
    REAL amnesty = minCredit - se_lagCredit * se_lagCreditSweetSpot;

    // and take it away from everyone
    if ( amnesty > 0 )
        for ( i = MAXCLIENTS; i>0; --i )
            se_serverLag[i].creditUsed_ -= amnesty;
}

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Member Data Documentation

REAL nServerLag::creditUsed_ [private]

the used lag credit

Definition at line 286 of file eLagCompensation.cpp.

Referenced by Balance(), CreditLeft(), Report(), Reset(), and TakeCredit().

double nServerLag::lastTime_ [private]

the last time lag credit was calculated

Definition at line 287 of file eLagCompensation.cpp.

Referenced by Reset(), and TakeCredit().

double nServerLag::lastLag_ [private]

the last time lag was reported to the client

Definition at line 288 of file eLagCompensation.cpp.

Referenced by Report(), and Reset().

int nServerLag::client_ [private]

the client this object is responsible for

Definition at line 289 of file eLagCompensation.cpp.

Referenced by Ping(), Report(), Reset(), and SetClient().

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The documentation for this class was generated from the following file:

• src/engine/eLagCompensation.cpp

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