/*****************************************************************************
*                                                                            *
*  OpenNI 1.0 Alpha                                                          *
*  Copyright (C) 2010 PrimeSense Ltd.                                        *
*                                                                            *
*  This file is part of OpenNI.                                              *
*                                                                            *
*  OpenNI is free software: you can redistribute it and/or modify            *
*  it under the terms of the GNU Lesser General Public License as published  *
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*  (at your option) any later version.                                       *
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*  OpenNI is distributed in the hope that it will be useful,                 *
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*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
*  GNU Lesser General Public License for more details.                       *
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*  You should have received a copy of the GNU Lesser General Public License  *
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*                                                                            *
*****************************************************************************/




#ifndef __XN_FPS_CALCULATOR_H__
#define __XN_FPS_CALCULATOR_H__

//---------------------------------------------------------------------------
// Includes
//---------------------------------------------------------------------------
#include <XnPlatform.h>
#include <XnStatus.h>

//---------------------------------------------------------------------------
// Types
//---------------------------------------------------------------------------
struct XnFPSDataImpl;
typedef struct XnFPSDataImpl* XnFPSData; 

//---------------------------------------------------------------------------
// Exported Functions
//---------------------------------------------------------------------------
/**
* This function initializes the FPS calculator.
* 
* @param	pFPS			[in]	A pointer to an XnFPSData struct.
* @param	nSamplesCount	[in]	The number of last frames to be kept.
*/
XN_C_API XnStatus xnFPSInit(XnFPSData* pFPS, XnUInt32 nSamplesCount);

/**
* This function marks that another frame was processed.
* 
* @param	pFPS	[in]	A pointer to an XnFPSData struct.
* @param	nNow	[in]	Optional. Current time. When not provided, function will take it itself.
*/
XN_C_API XnStatus xnFPSMarkFrame(XnFPSData* pFPS, XnUInt64 nNow = 0);
	
/**
* This function calculates the average FPS over the last frames.
* 
* @param	pFPS			[in]	A pointer to an XnFPSData struct.
* @param	nAverageOver	[in]	The number of milliseconds to average over.
* @param	nNow			[in]	Optional. Current time. When not provided, function will take it itself.
*/
XN_C_API XnDouble xnFPSCalc(XnFPSData* pFPS, XnUInt32 nAverageOver = 3000, XnUInt64 nNow = 0);

/**
* This function frees the FPS calculator.
* 
* @param	pFPS	[in]	A pointer to an XnFPSData struct.
*/
XN_C_API XnStatus xnFPSFree(XnFPSData* pFPS);

#endif //__XN_FPS_CALCULATOR_H__
