paex_ocean_shore.c File Reference

Generate Pink Noise using Gardner method, and make "waves". Provides an example of how to post stuff to/from the audio callback using lock-free FIFOs implemented by the PA ringbuffer. More...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include "portaudio.h"
#include "pa_ringbuffer.h"
#include "pa_util.h"

Data Structures
struct	PinkNoise
struct	BiQuad
struct	OceanWave
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	NEW_ROW_SIZE   (12 + (8*rand())/RAND_MAX)

Enumerations
enum	EnvState { State_kAttack , State_kPreDecay , State_kDecay , State_kCnt }

Functions
void	InitializePinkNoise (PinkNoise *pink, int numRows)
float	GeneratePinkNoise (PinkNoise *pink)
unsigned	GenerateWave (OceanWave *wave, float *output, unsigned noOfFrames)
float	ProcessBiquad (const BiQuad *coeffs, float *memory, float input)
OceanWave *	InitializeWave (double SR, float attackInSeconds, float maxLevel, float positionLeftRight)
int	main (void)

Detailed Description

Generate Pink Noise using Gardner method, and make "waves". Provides an example of how to post stuff to/from the audio callback using lock-free FIFOs implemented by the PA ringbuffer.

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 Robert Bielik

Macro Definition Documentation

NEW_ROW_SIZE

#define NEW_ROW_SIZE   (12 + (8*rand())/RAND_MAX)

Referenced by InitializeWave().

PINK_MAX_RANDOM_ROWS

#define PINK_MAX_RANDOM_ROWS   (30)

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().

Enumeration Type Documentation

EnvState

enum EnvState

Enumerator
State_kAttack
State_kPreDecay
State_kDecay
State_kCnt

Function Documentation

GeneratePinkNoise()

float GeneratePinkNoise

(

PinkNoise *

pink

)

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

Referenced by GenerateWave().

GenerateWave()

unsigned GenerateWave	(	OceanWave *	wave,
		float *	output,
		unsigned	noOfFrames )

References BiQuad::bq_a1, BiQuad::bq_a2, BiQuad::bq_b0, BiQuad::bq_b1, BiQuad::bq_b2, GeneratePinkNoise(), ProcessBiquad(), State_kAttack, State_kDecay, State_kPreDecay, OceanWave::wave_attack_incr, OceanWave::wave_bq_coeffs, OceanWave::wave_bq_left, OceanWave::wave_bq_right, OceanWave::wave_decay_incr, OceanWave::wave_envelope_level, OceanWave::wave_envelope_max_level, OceanWave::wave_envelope_state, OceanWave::wave_left, OceanWave::wave_pan_left, OceanWave::wave_pan_right, and OceanWave::wave_right.

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 InitializeWave().

InitializeWave()

OceanWave * InitializeWave	(	double	SR,
		float	attackInSeconds,
		float	maxLevel,
		float	positionLeftRight )

References InitializePinkNoise(), NEW_ROW_SIZE, PaUtil_AllocateZeroInitializedMemory(), State_kAttack, OceanWave::wave_attack_incr, OceanWave::wave_decay_incr, OceanWave::wave_envelope_level, OceanWave::wave_envelope_max_level, OceanWave::wave_envelope_state, OceanWave::wave_left, OceanWave::wave_pan_left, OceanWave::wave_pan_right, and OceanWave::wave_right.

Referenced by main().

main()

int main

(

void

)

References PaStreamParameters::channelCount, PaDeviceInfo::defaultLowOutputLatency, PaStreamParameters::device, PaStreamParameters::hostApiSpecificStreamInfo, InitializeWave(), paTestData::noOfActiveWaves, Pa_CloseStream(), Pa_GetDefaultOutputDevice(), Pa_GetDeviceInfo(), Pa_GetErrorText(), Pa_Initialize(), Pa_IsStreamActive(), Pa_OpenStream(), Pa_Sleep(), Pa_StartStream(), Pa_Terminate(), paDitherOff, paFloat32, paNoDevice, paNoError, PaUtil_AllocateZeroInitializedMemory(), PaUtil_FreeMemory(), PaUtil_GetRingBufferReadAvailable(), PaUtil_GetTime(), PaUtil_InitializeRingBuffer(), PaUtil_ReadRingBuffer(), PaUtil_WriteRingBuffer(), paTestData::rBufFromRT, paTestData::rBufFromRTData, paTestData::rBufToRT, paTestData::rBufToRTData, PaStreamParameters::sampleFormat, and PaStreamParameters::suggestedLatency.

ProcessBiquad()

float ProcessBiquad	(	const BiQuad *	coeffs,
		float *	memory,
		float	input )

References BiQuad::bq_a1, BiQuad::bq_a2, BiQuad::bq_b0, BiQuad::bq_b1, and BiQuad::bq_b2.

Referenced by GenerateWave().