//========= Copyright © 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=============================================================================//
#include "cbase.h"
#include "predicted_viewmodel.h"

// memdbgon must be the last include file in a .cpp file!!!
#include "tier0/memdbgon.h"

LINK_ENTITY_TO_CLASS( predicted_viewmodel, CPredictedViewModel );

IMPLEMENT_NETWORKCLASS_ALIASED( PredictedViewModel, DT_PredictedViewModel )

BEGIN_NETWORK_TABLE( CPredictedViewModel, DT_PredictedViewModel )
END_NETWORK_TABLE()

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
CPredictedViewModel::CPredictedViewModel()
{
#ifdef CLIENT_DLL
	m_vLagAngles.Init();
	m_LagAnglesHistory.Setup( &m_vLagAngles, 0 );
#endif
}

//-----------------------------------------------------------------------------
// Purpose: 
//-----------------------------------------------------------------------------
CPredictedViewModel::~CPredictedViewModel()
{
}

#ifdef CLIENT_DLL
ConVar cl_wpn_sway_interp( "cl_wpn_sway_interp", "0.1", FCVAR_CLIENTDLL );
ConVar cl_wpn_sway_scale( "cl_wpn_sway_scale", "1.0", FCVAR_CLIENTDLL );
#endif

void CPredictedViewModel::CalcViewModelLag( Vector& origin, QAngle& angles, QAngle& original_angles )
{
	#ifdef CLIENT_DLL
		// Calculate our drift
		Vector	forward, right, up;
		AngleVectors( angles, &forward, &right, &up );
		
		// Add an entry to the history.
		m_vLagAngles = angles;
		m_LagAnglesHistory.NoteChanged( gpGlobals->curtime, cl_wpn_sway_interp.GetFloat() );
		
		// Interpolate back 100ms.
		m_LagAnglesHistory.Interpolate( gpGlobals->curtime, cl_wpn_sway_interp.GetFloat() );
		
		// Now take the 100ms angle difference and figure out how far the forward vector moved in local space.
		Vector vLaggedForward;
		QAngle angleDiff = m_vLagAngles - angles;
		AngleVectors( -angleDiff, &vLaggedForward, 0, 0 );
		Vector vForwardDiff = Vector(1,0,0) - vLaggedForward;

		// Now offset the origin using that.
		vForwardDiff *= cl_wpn_sway_scale.GetFloat();
		origin += forward*vForwardDiff.x + right*-vForwardDiff.y + up*vForwardDiff.z;
	#endif
}