FilterGenerator.h

/*
 * ----------------------------------------------------------------
 *
 *		ITA geometrical acoustics
 *		(c) Copyright Institute of Technical Acoustics (ITA)
 *		RWTH Aachen University, Germany, 2015-2018
 *
 * ----------------------------------------------------------------
 *				    ____  __________  _______
 *				   //  / //__   ___/ //  _   |
 *				  //  /    //  /    //  /_|  |
 *				 //  /    //  /    //  ___   |
 *				//__/    //__/    //__/   |__|
 *
 * ----------------------------------------------------------------
 *
 */

#ifndef INCLUDE_WATCHER_ITA_PROPAGATION_MODELS_FILTER_GENERATOR
#define INCLUDE_WATCHER_ITA_PROPAGATION_MODELS_FILTER_GENERATOR

#include "Base.h"
#include "Definitions.h"
#include "DiffractionFilter.h"

// ITA includes
#include <ITAGeo/Base.h>
#include <ITAHDFTSpectra.h>
#include <ITAHDFTSpectrum.h>

// STL includes
#include <vector>

namespace ITAPropagationModels
{
	//! Transfer function filter generator for propagation paths
	/**
	  * Generates transfer functions in the frequency-domain that
	  * can be used as filters, e.g. for auralization.
	  */
	class ITA_PROPAGATION_MODELS_API CTFGenerator
	{
	public:

		//! Construct a generator with predetermined output channels, e.g. for binaural or SH filters
		/**
		  * @param[in] iNumOutputChannels Number of output channels
		  * @param[in] iDFTSize Length of the DFT used to construct and combine filter components
		  * @param[in] fSamplingRate Filer sampling rate
		  */
		CTFGenerator( const int iNumOutputChannels, const int iDFTSize = 128, const float fSamplingRate = 44100.0f );

		//! Cunstruct a generator with matching properties of a target spectrum
		inline CTFGenerator( const ITABase::CHDFTSpectrum& pTransferFunction )
			: CTFGenerator( 1, pTransferFunction.GetDFTSize(), pTransferFunction.GetSampleRate() )
		{
		};

		//! Cunstruct a generator with matching properties of multi-channel target spectra
		CTFGenerator( const ITABase::CHDFTSpectra& pTransferFunctions )
			: CTFGenerator( pTransferFunctions.GetNumChannels(), pTransferFunctions.GetDFTSize(), pTransferFunctions.GetSampleRate() )
		{
		};

		//! Generate a single-channel transfer function
		inline void GenerateTF( ITABase::CHDFTSpectrum& pTransferFunction )
		{
			const std::vector< ITABase::CHDFTSpectrum* > vpSpectra = { &( pTransferFunction ) };
			ITABase::CHDFTSpectra oTF( vpSpectra );
			GenerateTF( oTF );
		};

		//! Generate a multi-channel transfer function
		inline void GenerateTF( ITABase::CHDFTSpectra& pTransferFunctions );

	private:
	};
}

#endif // INCLUDE_WATCHER_ITA_PROPAGATION_MODELS_FILTER_GENERATOR