| 1 | #include <stdio.h> |
| 2 | #include <stdlib.h> |
| 3 | #include <unistd.h> |
| 4 | #include <math.h> |
| 5 | #include "SDL.h" |
| 6 | #include "SDL_mixer.h" |
| 7 | |
| 8 | #define PI 3.1415 |
| 9 | #define deg2rad(a) (((a)/180)*PI) |
| 10 | |
| 11 | |
| 12 | SDL_AudioSpec *desired, *obtained; |
| 13 | SDL_AudioSpec *hardware_spec; |
| 14 | |
| 15 | |
| 16 | void my_audio_callback(void *userdata, Uint8 *stream, int len) { |
| 17 | int sampl_freq = desired->freq; |
| 18 | sampl_freq = 44100; |
| 19 | |
| 20 | double sine_freq = 50; |
| 21 | static double i,j; // = 0; |
| 22 | |
| 23 | short int *u; u = (short int *)stream; |
| 24 | //for(;len>0;len--) *(u++) = random(); |
| 25 | while( (void *)u<(void *)(stream+len) ) { |
| 26 | // *(u++) = 0; |
| 27 | *(u++) = sin( |
| 28 | i += (2*PI*sine_freq)/sampl_freq |
| 29 | )*128000; |
| 30 | // *(u++) = sin(deg2rad(j+=8))*1280000; |
| 31 | // *(u++) = 0; |
| 32 | *(u++) = *(u-1); |
| 33 | } |
| 34 | //if(i>=2*PI) i=0; |
| 35 | //if(j>=2*PI) j=0; |
| 36 | } |
| 37 | |
| 38 | |
| 39 | int main(int argc, char *argv[]) { |
| 40 | |
| 41 | /* Allocate a desired SDL_AudioSpec */ |
| 42 | desired=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); |
| 43 | |
| 44 | /* Allocate space for the obtained SDL_AudioSpec */ |
| 45 | obtained=(SDL_AudioSpec *)malloc(sizeof(SDL_AudioSpec)); |
| 46 | |
| 47 | /* 22050Hz - FM Radio quality */ |
| 48 | desired->freq=22050; |
| 49 | desired->freq=44100; |
| 50 | |
| 51 | /* 16-bit signed audio */ |
| 52 | desired->format=AUDIO_S16LSB; |
| 53 | //desired->format=AUDIO_S8; |
| 54 | |
| 55 | desired->channels=2; //0,1,2 = autodetect,mono,stereo |
| 56 | |
| 57 | /* Large audio buffer reduces risk of dropouts but increases response time */ |
| 58 | desired->samples=65530; |
| 59 | |
| 60 | /* Our callback function */ |
| 61 | desired->callback=my_audio_callback; |
| 62 | |
| 63 | desired->userdata=NULL; |
| 64 | desired->userdata=&desired->freq; |
| 65 | |
| 66 | /* Open the audio device */ |
| 67 | if ( SDL_OpenAudio(desired, obtained) < 0 ){ |
| 68 | fprintf(stderr, "Couldn't open audio: %s", SDL_GetError()); |
| 69 | exit(-1); |
| 70 | } |
| 71 | /* desired spec is no longer needed */ |
| 72 | free(desired); |
| 73 | hardware_spec=obtained; |
| 74 | |
| 75 | /* Prepare callback for playing */ |
| 76 | |
| 77 | /* Start playing */ |
| 78 | SDL_PauseAudio(0); |
| 79 | sleep(100); |
| 80 | } |