00001 00006 /* 00007 * $Id: paex_saw.c 1752 2011-09-08 03:21:55Z philburk $ 00008 * 00009 * This program uses the PortAudio Portable Audio Library. 00010 * For more information see: http://www.portaudio.com 00011 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk 00012 * 00013 * Permission is hereby granted, free of charge, to any person obtaining 00014 * a copy of this software and associated documentation files 00015 * (the "Software"), to deal in the Software without restriction, 00016 * including without limitation the rights to use, copy, modify, merge, 00017 * publish, distribute, sublicense, and/or sell copies of the Software, 00018 * and to permit persons to whom the Software is furnished to do so, 00019 * subject to the following conditions: 00020 * 00021 * The above copyright notice and this permission notice shall be 00022 * included in all copies or substantial portions of the Software. 00023 * 00024 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 00025 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 00026 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 00027 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR 00028 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 00029 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 00030 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 00031 */ 00032 00033 /* 00034 * The text above constitutes the entire PortAudio license; however, 00035 * the PortAudio community also makes the following non-binding requests: 00036 * 00037 * Any person wishing to distribute modifications to the Software is 00038 * requested to send the modifications to the original developer so that 00039 * they can be incorporated into the canonical version. It is also 00040 * requested that these non-binding requests be included along with the 00041 * license above. 00042 */ 00043 00044 #include <stdio.h> 00045 #include <math.h> 00046 #include "portaudio.h" 00047 #define NUM_SECONDS (4) 00048 #define SAMPLE_RATE (44100) 00049 00050 typedef struct 00051 { 00052 float left_phase; 00053 float right_phase; 00054 } 00055 paTestData; 00056 00057 /* This routine will be called by the PortAudio engine when audio is needed. 00058 ** It may called at interrupt level on some machines so don't do anything 00059 ** that could mess up the system like calling malloc() or free(). 00060 */ 00061 static int patestCallback( const void *inputBuffer, void *outputBuffer, 00062 unsigned long framesPerBuffer, 00063 const PaStreamCallbackTimeInfo* timeInfo, 00064 PaStreamCallbackFlags statusFlags, 00065 void *userData ) 00066 { 00067 /* Cast data passed through stream to our structure. */ 00068 paTestData *data = (paTestData*)userData; 00069 float *out = (float*)outputBuffer; 00070 unsigned int i; 00071 (void) inputBuffer; /* Prevent unused variable warning. */ 00072 00073 for( i=0; i<framesPerBuffer; i++ ) 00074 { 00075 *out++ = data->left_phase; /* left */ 00076 *out++ = data->right_phase; /* right */ 00077 /* Generate simple sawtooth phaser that ranges between -1.0 and 1.0. */ 00078 data->left_phase += 0.01f; 00079 /* When signal reaches top, drop back down. */ 00080 if( data->left_phase >= 1.0f ) data->left_phase -= 2.0f; 00081 /* higher pitch so we can distinguish left and right. */ 00082 data->right_phase += 0.03f; 00083 if( data->right_phase >= 1.0f ) data->right_phase -= 2.0f; 00084 } 00085 return 0; 00086 } 00087 00088 /*******************************************************************/ 00089 static paTestData data; 00090 int main(void); 00091 int main(void) 00092 { 00093 PaStream *stream; 00094 PaError err; 00095 00096 printf("PortAudio Test: output sawtooth wave.\n"); 00097 /* Initialize our data for use by callback. */ 00098 data.left_phase = data.right_phase = 0.0; 00099 /* Initialize library before making any other calls. */ 00100 err = Pa_Initialize(); 00101 if( err != paNoError ) goto error; 00102 00103 /* Open an audio I/O stream. */ 00104 err = Pa_OpenDefaultStream( &stream, 00105 0, /* no input channels */ 00106 2, /* stereo output */ 00107 paFloat32, /* 32 bit floating point output */ 00108 SAMPLE_RATE, 00109 256, /* frames per buffer */ 00110 patestCallback, 00111 &data ); 00112 if( err != paNoError ) goto error; 00113 00114 err = Pa_StartStream( stream ); 00115 if( err != paNoError ) goto error; 00116 00117 /* Sleep for several seconds. */ 00118 Pa_Sleep(NUM_SECONDS*1000); 00119 00120 err = Pa_StopStream( stream ); 00121 if( err != paNoError ) goto error; 00122 err = Pa_CloseStream( stream ); 00123 if( err != paNoError ) goto error; 00124 Pa_Terminate(); 00125 printf("Test finished.\n"); 00126 return err; 00127 error: 00128 Pa_Terminate(); 00129 fprintf( stderr, "An error occured while using the portaudio stream\n" ); 00130 fprintf( stderr, "Error number: %d\n", err ); 00131 fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) ); 00132 return err; 00133 }