111 lines
3 KiB
C
111 lines
3 KiB
C
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#include <portaudio.h>
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#include <math.h>
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#include <stdio.h>
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#define SAMPLE_RATE 44100
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static int patestCallback(const void *inputBuffer, void *outputBuffer,
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unsigned long framesPerBuffer,
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const PaStreamCallbackTimeInfo* timeInfo,
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PaStreamCallbackFlags statusFlags,
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void *userData);
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static PaStream *sin_stream;
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PaError play_sin(void)
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{
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PaError err;
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// PaDeviceInfo *info;
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// int numDevices;
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// printf("Found Devices:\n");
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// numDevices = Pa_GetDeviceCount();
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// for(i = 0; i < numDevices; ++i)
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// {
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// info = Pa_GetDeviceInfo(i);
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// printf("%s\n", info->name);
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// }
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err = Pa_OpenDefaultStream(&sin_stream,
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0, /* no input channels */
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2, /* stereo output */
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paFloat32, /* 32 bit floating point output */
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SAMPLE_RATE,
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1024, /* frames per buffer, i.e. the number of sample frames
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that PortAudio will request from the callback. Many
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apps may want to use paFramesPerBufferUnspecified,
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which tells PortAudio to pick the best, possibly
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changing, buffer size.*/
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patestCallback, /* this is your callback function */
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NULL); /*This is a pointer that will be passed to your callback*/
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if(err != paNoError)
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{
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return err;
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}
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err = Pa_StartStream(sin_stream);
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if(err != paNoError)
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{
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return err;
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}
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return paNoError;
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}
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PaError stop_sin(void)
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{
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PaError err;
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err = Pa_StopStream(sin_stream);
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if(err != paNoError)
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{
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return err;
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}
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err = Pa_CloseStream(sin_stream);
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if( err != paNoError )
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{
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return err;
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}
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return paNoError;
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}
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/*
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* This routine will be called by the PortAudio engine when audio is needed.
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* It may called at interrupt level on some machines so don't do anything that
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* could mess up the system like calling malloc() or free().
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*/
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static int patestCallback(const void *inputBuffer, void *outputBuffer,
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unsigned long framesPerBuffer,
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const PaStreamCallbackTimeInfo* timeInfo,
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PaStreamCallbackFlags statusFlags,
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void *userData)
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{
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float freq_l = 100;
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float freq_r = 150;
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static float phase_l = 0;
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static float phase_r = 0;
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float *out = (float*)outputBuffer;
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unsigned int i;
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for(i=0; i<framesPerBuffer; i++)
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{
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/* should modulo by 2PI */
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phase_l += (2 * M_PI * freq_l / SAMPLE_RATE);
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if(phase_l > 2 * M_PI)
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{
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phase_l -= 2 * M_PI;
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}
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phase_r += (2 * M_PI * freq_r / SAMPLE_RATE);
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if(phase_r > 2 * M_PI)
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{
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phase_r -= 2 * M_PI;
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}
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out[2*i] = sin(phase_l);
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out[2*i + 1] = sin(phase_r);
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}
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return 0;
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}
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