source-engine/engine/clockdriftmgr.h

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2020-04-22 16:56:21 +00:00
//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=============================================================================//
#ifndef CLOCKDRIFTMGR_H
#define CLOCKDRIFTMGR_H
#ifdef _WIN32
#pragma once
#endif
class CClockDriftMgr
{
friend class CBaseClientState;
public:
CClockDriftMgr();
// Is clock correction even enabled right now?
static bool IsClockCorrectionEnabled();
// Clear our state.
void Clear();
// This is called each time a server packet comes in. It is used to correlate
// where the server is in time compared to us.
void SetServerTick( int iServerTick );
// Pass in the frametime you would use, and it will drift it towards the server clock.
float AdjustFrameTime( float inputFrameTime );
// Returns how many ticks ahead of the server the client is.
float GetCurrentClockDifference() const;
private:
void ShowDebugInfo( float flAdjustment );
// This scales the offsets so the average produced is equal to the
// current average + flAmount. This way, as we add corrections,
// we lower the average accordingly so we don't keep responding
// as much as we need to after we'd adjusted it a couple times.
void AdjustAverageDifferenceBy( float flAmountInSeconds );
private:
enum
{
// This controls how much it smoothes out the samples from the server.
NUM_CLOCKDRIFT_SAMPLES=16
};
// This holds how many ticks the client is ahead each time we get a server tick.
// We average these together to get our estimate of how far ahead we are.
float m_ClockOffsets[NUM_CLOCKDRIFT_SAMPLES];
int m_iCurClockOffset;
int m_nServerTick; // Last-received tick from the server.
int m_nClientTick; // The client's own tick counter (specifically, for interpolation during rendering).
// The server may be on a slightly different tick and the client will drift towards it.
};
#endif // CLOCKDRIFTMGR_H