paex_pink.c File Reference

Generate Pink Noise using Gardner method. More...

#include <stdio.h>
#include <math.h>
#include "portaudio.h"

Data Structures
struct	PinkNoise
struct	paTestData

Macros
#define	PINK_MAX_RANDOM_ROWS   (30)
#define	PINK_RANDOM_BITS   (24)
#define	PINK_RANDOM_SHIFT   ((sizeof(long)*8)-PINK_RANDOM_BITS)
#define	PINK_MEASURE
#define	PINK_TEST

Functions
void	InitializePinkNoise (PinkNoise *pink, int numRows)
float	GeneratePinkNoise (PinkNoise *pink)
int	main (void)

Variables
float	pinkMax = -999.0
float	pinkMin = 999.0

Detailed Description

Generate Pink Noise using Gardner method.

Optimization suggested by James McCartney uses a tree to select which random value to replace.

    x x x x x x x x x x x x x x x x
    x   x   x   x   x   x   x   x
    x       x       x       x
     x               x
       x

Tree is generated by counting trailing zeros in an increasing index. When the index is zero, no random number is selected.

Author

Phil Burk http://www.softsynth.com

Macro Definition Documentation

PINK_MAX_RANDOM_ROWS

#define PINK_MAX_RANDOM_ROWS   (30)

PINK_MEASURE

#define PINK_MEASURE

PINK_RANDOM_BITS

#define PINK_RANDOM_BITS   (24)

Referenced by InitializePinkNoise().

PINK_RANDOM_SHIFT

#define PINK_RANDOM_SHIFT   ((sizeof(long)*8)-PINK_RANDOM_BITS)

Referenced by GeneratePinkNoise().

PINK_TEST

#define PINK_TEST

Function Documentation

GeneratePinkNoise()

float GeneratePinkNoise

(

PinkNoise *

pink

)

References PinkNoise::pink_Index, PinkNoise::pink_IndexMask, PINK_RANDOM_SHIFT, PinkNoise::pink_Rows, PinkNoise::pink_RunningSum, PinkNoise::pink_Scalar, pinkMax, and pinkMin.

Referenced by main().

InitializePinkNoise()

void InitializePinkNoise	(	PinkNoise *	pink,
		int	numRows )

References PinkNoise::pink_Index, PinkNoise::pink_IndexMask, PINK_RANDOM_BITS, PinkNoise::pink_Rows, PinkNoise::pink_RunningSum, and PinkNoise::pink_Scalar.

Referenced by main().

main()

int main

(

void

)

References PaStreamParameters::channelCount, PaDeviceInfo::defaultLowOutputLatency, PaStreamParameters::device, GeneratePinkNoise(), PaStreamParameters::hostApiSpecificStreamInfo, InitializePinkNoise(), paTestData::leftPink, Pa_CloseStream(), Pa_GetDefaultOutputDevice(), Pa_GetDeviceInfo(), Pa_GetErrorText(), Pa_Initialize(), Pa_IsStreamActive(), Pa_OpenStream(), Pa_Sleep(), Pa_StartStream(), Pa_Terminate(), paClipOff, paFloat32, paNoDevice, paNoError, pinkMax, pinkMin, paTestData::rightPink, PaStreamParameters::sampleFormat, paTestData::sampsToGo, and PaStreamParameters::suggestedLatency.

Variable Documentation

pinkMax

float pinkMax = -999.0

Referenced by GeneratePinkNoise(), and main().

pinkMin

float pinkMin = 999.0

Referenced by GeneratePinkNoise(), and main().