1 files changed, 68 insertions, 0 deletions
diff --git a/engine/clockdriftmgr.h b/engine/clockdriftmgr.h
new file mode 100644
index 0000000..e445596
--- /dev/null
+++ b/engine/clockdriftmgr.h
@@ -0,0 +1,68 @@
+//========= 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