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Diffstat (limited to '3rdparty/portaudio/examples/paex_pink.c')
| -rw-r--r-- | 3rdparty/portaudio/examples/paex_pink.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/3rdparty/portaudio/examples/paex_pink.c b/3rdparty/portaudio/examples/paex_pink.c new file mode 100644 index 0000000..519f979 --- /dev/null +++ b/3rdparty/portaudio/examples/paex_pink.c @@ -0,0 +1,280 @@ +/** @file paex_pink.c + @ingroup examples_src + @brief Generate Pink Noise using Gardner method. + + Optimization suggested by James McCartney uses a tree + to select which random value to replace. +<pre> + 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 +</pre> + 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 +*/ +/* + * $Id$ + * + * This program uses the PortAudio Portable Audio Library. + * For more information see: http://www.portaudio.com + * Copyright (c) 1999-2000 Ross Bencina and Phil Burk + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files + * (the "Software"), to deal in the Software without restriction, + * including without limitation the rights to use, copy, modify, merge, + * publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, + * subject to the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +/* + * The text above constitutes the entire PortAudio license; however, + * the PortAudio community also makes the following non-binding requests: + * + * Any person wishing to distribute modifications to the Software is + * requested to send the modifications to the original developer so that + * they can be incorporated into the canonical version. It is also + * requested that these non-binding requests be included along with the + * license above. + */ + +#include <stdio.h> +#include <math.h> +#include "portaudio.h" + +#define PINK_MAX_RANDOM_ROWS (30) +#define PINK_RANDOM_BITS (24) +#define PINK_RANDOM_SHIFT ((sizeof(long)*8)-PINK_RANDOM_BITS) + +typedef struct +{ + long pink_Rows[PINK_MAX_RANDOM_ROWS]; + long pink_RunningSum; /* Used to optimize summing of generators. */ + int pink_Index; /* Incremented each sample. */ + int pink_IndexMask; /* Index wrapped by ANDing with this mask. */ + float pink_Scalar; /* Used to scale within range of -1.0 to +1.0 */ +} +PinkNoise; + +/* Prototypes */ +static unsigned long GenerateRandomNumber( void ); +void InitializePinkNoise( PinkNoise *pink, int numRows ); +float GeneratePinkNoise( PinkNoise *pink ); + +/************************************************************/ +/* Calculate pseudo-random 32 bit number based on linear congruential method. */ +static unsigned long GenerateRandomNumber( void ) +{ + /* Change this seed for different random sequences. */ + static unsigned long randSeed = 22222; + randSeed = (randSeed * 196314165) + 907633515; + return randSeed; +} + +/************************************************************/ +/* Setup PinkNoise structure for N rows of generators. */ +void InitializePinkNoise( PinkNoise *pink, int numRows ) +{ + int i; + long pmax; + pink->pink_Index = 0; + pink->pink_IndexMask = (1<<numRows) - 1; + /* Calculate maximum possible signed random value. Extra 1 for white noise always added. */ + pmax = (numRows + 1) * (1<<(PINK_RANDOM_BITS-1)); + pink->pink_Scalar = 1.0f / pmax; + /* Initialize rows. */ + for( i=0; i<numRows; i++ ) pink->pink_Rows[i] = 0; + pink->pink_RunningSum = 0; +} + +#define PINK_MEASURE +#ifdef PINK_MEASURE +float pinkMax = -999.0; +float pinkMin = 999.0; +#endif + +/* Generate Pink noise values between -1.0 and +1.0 */ +float GeneratePinkNoise( PinkNoise *pink ) +{ + long newRandom; + long sum; + float output; + /* Increment and mask index. */ + pink->pink_Index = (pink->pink_Index + 1) & pink->pink_IndexMask; + /* If index is zero, don't update any random values. */ + if( pink->pink_Index != 0 ) + { + /* Determine how many trailing zeros in PinkIndex. */ + /* This algorithm will hang if n==0 so test first. */ + int numZeros = 0; + int n = pink->pink_Index; + while( (n & 1) == 0 ) + { + n = n >> 1; + numZeros++; + } + /* Replace the indexed ROWS random value. + * Subtract and add back to RunningSum instead of adding all the random + * values together. Only one changes each time. + */ + pink->pink_RunningSum -= pink->pink_Rows[numZeros]; + newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT; + pink->pink_RunningSum += newRandom; + pink->pink_Rows[numZeros] = newRandom; + } + + /* Add extra white noise value. */ + newRandom = ((long)GenerateRandomNumber()) >> PINK_RANDOM_SHIFT; + sum = pink->pink_RunningSum + newRandom; + /* Scale to range of -1.0 to 0.9999. */ + output = pink->pink_Scalar * sum; +#ifdef PINK_MEASURE + /* Check Min/Max */ + if( output > pinkMax ) pinkMax = output; + else if( output < pinkMin ) pinkMin = output; +#endif + return output; +} + +/*******************************************************************/ +#define PINK_TEST +#ifdef PINK_TEST + +/* Context for callback routine. */ +typedef struct +{ + PinkNoise leftPink; + PinkNoise rightPink; + unsigned int sampsToGo; +} +paTestData; + +/* This routine will be called by the PortAudio engine when audio is needed. +** It may called at interrupt level on some machines so don't do anything +** that could mess up the system like calling malloc() or free(). +*/ +static int patestCallback(const void* inputBuffer, + void* outputBuffer, + unsigned long framesPerBuffer, + const PaStreamCallbackTimeInfo* timeInfo, + PaStreamCallbackFlags statusFlags, + void* userData) +{ + int finished; + int i; + int numFrames; + paTestData *data = (paTestData*)userData; + float *out = (float*)outputBuffer; + (void) inputBuffer; /* Prevent "unused variable" warnings. */ + + /* Are we almost at end. */ + if( data->sampsToGo < framesPerBuffer ) + { + numFrames = data->sampsToGo; + finished = 1; + } + else + { + numFrames = framesPerBuffer; + finished = 0; + } + for( i=0; i<numFrames; i++ ) + { + *out++ = GeneratePinkNoise( &data->leftPink ); + *out++ = GeneratePinkNoise( &data->rightPink ); + } + data->sampsToGo -= numFrames; + return finished; +} + +/*******************************************************************/ +int main(void); +int main(void) +{ + PaStream* stream; + PaError err; + paTestData data; + PaStreamParameters outputParameters; + int totalSamps; + static const double SR = 44100.0; + static const int FPB = 2048; /* Frames per buffer: 46 ms buffers. */ + + /* Initialize two pink noise signals with different numbers of rows. */ + InitializePinkNoise( &data.leftPink, 12 ); + InitializePinkNoise( &data.rightPink, 16 ); + + /* Look at a few values. */ + { + int i; + float pink; + for( i=0; i<20; i++ ) + { + pink = GeneratePinkNoise( &data.leftPink ); + printf("Pink = %f\n", pink ); + } + } + + data.sampsToGo = totalSamps = (int)(60.0 * SR); /* Play a whole minute. */ + err = Pa_Initialize(); + if( err != paNoError ) goto error; + + /* Open a stereo PortAudio stream so we can hear the result. */ + outputParameters.device = Pa_GetDefaultOutputDevice(); /* Take the default output device. */ + if (outputParameters.device == paNoDevice) { + fprintf(stderr,"Error: No default output device.\n"); + goto error; + } + outputParameters.channelCount = 2; /* Stereo output, most likely supported. */ + outputParameters.hostApiSpecificStreamInfo = NULL; + outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output. */ + outputParameters.suggestedLatency = + Pa_GetDeviceInfo(outputParameters.device)->defaultLowOutputLatency; + err = Pa_OpenStream(&stream, + NULL, /* No input. */ + &outputParameters, + SR, /* Sample rate. */ + FPB, /* Frames per buffer. */ + paClipOff, /* we won't output out of range samples so don't bother clipping them */ + patestCallback, + &data); + if( err != paNoError ) goto error; + + err = Pa_StartStream( stream ); + if( err != paNoError ) goto error; + + printf("Stereo pink noise for one minute...\n"); + + while( ( err = Pa_IsStreamActive( stream ) ) == 1 ) Pa_Sleep(100); + if( err < 0 ) goto error; + + err = Pa_CloseStream( stream ); + if( err != paNoError ) goto error; +#ifdef PINK_MEASURE + printf("Pink min = %f, max = %f\n", pinkMin, pinkMax ); +#endif + Pa_Terminate(); + return 0; +error: + Pa_Terminate(); + fprintf( stderr, "An error occurred while using the portaudio stream\n" ); + fprintf( stderr, "Error number: %d\n", err ); + fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) ); + return 0; +} +#endif /* PINK_TEST */ |