128 lines
3.7 KiB
C
128 lines
3.7 KiB
C
#include <audio.h>
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#include <math.h>
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#include <portaudio.h>
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#define SAMPLE_RATE 44100
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#define FRAMES_PER_BUFFER 64
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#define TABLE_SIZE 44100
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#define M_PI 3.14159265
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static float sine[TABLE_SIZE];
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static unsigned long ind = 0;
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static unsigned long ind2 = 0;
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static int sq1_on_time;
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static int sq1_off_time;
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static float sq1 = 1;
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static int sq1_timer = 0;
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static int sq2_on_time;
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static int sq2_off_time;
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static float sq2 = 1;
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static int sq2_timer = 0;
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static audio_context ctx;
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static int audio_callback(const void* input_uffer, void *output_buffer,
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unsigned long framesPerBuffer,
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const PaStreamCallbackTimeInfo *time_info,
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PaStreamCallbackFlags status_flags,
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void *userData ) {
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//printf("Audio Callback!\n");
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audio_context *ctx = (audio_context *) userData;
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float *out = (float *)output_buffer;
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PaTime time = time_info->currentTime;
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sq1_on_time = 1/(ctx->sq1_freq/(float)SAMPLE_RATE) * ctx->sq1_duty;
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sq1_off_time = 1/(ctx->sq1_freq/(float)SAMPLE_RATE) * (1 - ctx->sq1_duty);
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sq2_on_time = 1/(ctx->sq2_freq/(float)SAMPLE_RATE) * ctx->sq2_duty;
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sq2_off_time = 1/(ctx->sq2_freq/(float)SAMPLE_RATE) * (1 - ctx->sq2_duty);
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for(int i = 0; i < framesPerBuffer; i++) {
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float val = 0;
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//handle audio channels
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//val += 0.2 * sine[ind];
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//ind += 500;
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if((sq1_timer >= sq1_on_time && sq1 == 1)) {
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sq1 = 0;
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sq1_timer = 0;
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} else if((sq1_timer >= sq1_off_time && sq1 == 0)){
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sq1 = 1;
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sq1_timer = 0;
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}
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sq1_timer++;
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val += ctx->sq1_amp * sq1;
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if((sq2_timer >= sq2_on_time && sq2 == 1)) {
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sq2 = 0;
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sq2_timer = 0;
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} else if((sq2_timer >= sq2_off_time && sq2 == 0)){
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sq2 = 1;
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sq2_timer = 0;
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}
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sq2_timer++;
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val += ctx->sq2_amp * sq2;
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//val += 0.2 * sine[ind2];
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//ind2 += 200;
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if(ind >= TABLE_SIZE) ind -= TABLE_SIZE;
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if(ind2 >= TABLE_SIZE) ind2 -= TABLE_SIZE;
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*out++ = val;
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}
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return paContinue;
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}
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void audio_init(){
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PaStreamParameters output_parameters;
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PaStream *stream;
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PaError err;
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ctx.sq1_amp = 0.2;
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ctx.sq1_duty = 0.5;
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ctx.sq1_freq = 200;
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ctx.sq2_amp = 0;
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ctx.sq2_duty = 0.5;
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ctx.sq2_freq = 400;
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for(int i = 0; i < TABLE_SIZE; i++) {
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sine[i] = (float) sin(((double)i/(double)TABLE_SIZE) * M_PI * 2.);
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}
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err = Pa_Initialize();
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if (err != paNoError) goto error;
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output_parameters.device = Pa_GetDefaultOutputDevice();
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if(output_parameters.device == paNoDevice) {
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fprintf(stderr, "No default audio device!\n");
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goto error;
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}
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output_parameters.channelCount = 1;
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output_parameters.sampleFormat = paFloat32;
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output_parameters.suggestedLatency = Pa_GetDeviceInfo(output_parameters.device)->defaultLowOutputLatency;
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output_parameters.hostApiSpecificStreamInfo = NULL;
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err = Pa_OpenStream(&stream,
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NULL,
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&output_parameters,
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SAMPLE_RATE,
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FRAMES_PER_BUFFER,
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NULL,
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audio_callback,
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&ctx);
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if(err != paNoError) goto error;
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err = Pa_StartStream(stream);
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if(err != paNoError) goto error;
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return;
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error:
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Pa_Terminate();
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fprintf(stderr, "portaudio stream error\n\tError Number: %d\n\tError Message: %s\n", err, Pa_GetErrorText(err));
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}
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static int change = 1;
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void audio_tick(){
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ctx.sq1_freq += change;
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if(ctx.sq1_freq >= 600 || ctx.sq1_freq <= 200) {
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change = -change;
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}
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} |