FastFFT Class Reference

The FastFFT provides a simple wrapper for the FFTW FFT operation - it is ultra-thin and simple to use. More...

#include <fxobjects.h>

Public Member Functions
void	initialize (unsigned int _frameLength, windowType _window)
	initialize the Fast FFT object for operation
void	destroyFFTW ()
	destroys the FFTW arrays and plans.
fftw_complex *	doFFT (double *inputReal, double *inputImag=nullptr)
	perform the FFT operation
fftw_complex *	doInverseFFT (double *inputReal, double *inputImag)
	perform the IFFT operation
unsigned int	getFrameLength ()

Protected Attributes
fftw_complex *	fft_input = nullptr
	array for FFT input
fftw_complex *	fft_result = nullptr
	array for FFT output
fftw_complex *	ifft_input = nullptr
	array for IFFT input
fftw_complex *	ifft_result = nullptr
	array for IFFT output
fftw_plan	plan_forward = nullptr
	FFTW plan for FFT.
fftw_plan	plan_backward = nullptr
	FFTW plan for IFFT.
double *	windowBuffer = nullptr
	buffer for window (naked)
double	windowGainCorrection = 1.0
	window gain correction
windowType	window = windowType::kHannWindow
	window type
unsigned int	frameLength = 0
	current FFT length

Detailed Description

The FastFFT provides a simple wrapper for the FFTW FFT operation - it is ultra-thin and simple to use.

Audio I/O:

• processes mono inputs into FFT outputs.

Control I/F:

• none.

Author

Will Pirkle http://www.willpirkle.com

Remarks

This object is included in Designing Audio Effects Plugins in C++ 2nd Ed. by Will Pirkle

Version

Revision : 1.0

Date

Date : 2018 / 09 / 7

Member Function Documentation

destroyFFTW()

void FastFFT::destroyFFTW

(

)

destroys the FFTW arrays and plans.

destroy FFTW objects and plans

doFFT()

fftw_complex * FastFFT::doFFT	(	double *	inputReal,
		double *	inputImag = nullptr
	)

perform the FFT operation

do the FFT and return real and imaginary arrays

• NOTES:
  

Parameters

inputReal	an array of real valued points
inputImag	an array of imaginary valued points (will be 0 for audio which is real-valued)

Returns

a pointer to a fftw_complex array: a 2D array of real (column 0) and imaginary (column 1) parts

doInverseFFT()

fftw_complex * FastFFT::doInverseFFT	(	double *	inputReal,
		double *	inputImag
	)

perform the IFFT operation

do the IFFT and return real and imaginary arrays

• NOTES:
  

Parameters

inputReal	an array of real valued points
inputImag	an array of imaginary valued points (will be 0 for audio which is real-valued)

Returns

a pointer to a fftw_complex array: a 2D array of real (column 0) and imaginary (column 1) parts

getFrameLength()

unsigned int FastFFT::getFrameLength ( )

inline

get the current FFT length

initialize()

void FastFFT::initialize	(	unsigned int	_frameLength,
		windowType	_window
	)

initialize the Fast FFT object for operation

setup the FFT for a given framelength and window type

• NOTES:
  See notes on symmetrical window arrays in comments.
  

Parameters

_frameLength	the FFT length - MUST be a power of 2
_window	the window type (note: may be set to windowType::kNone)

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The documentation for this class was generated from the following files:

• C:/RackAFX_v7/ASPIK_Doxygen/PluginObjects/fxobjects.h
• C:/RackAFX_v7/ASPIK_Doxygen/PluginObjects/fxobjects.cpp