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#include <stdio.h>
#include <stdlib.h>
#include <float.h>
#include <time.h>
#include <limits.h>
#include <string.h>
#include <math.h>
#include "guttersynth.h"
int samples_per_second = 44100;
int bits_per_sample = 16;
char* output_name = "guttersynth-example1.wav";
int written_samples = 0;
struct wavfile_header {
char riff_tag[4];
int riff_length;
char wave_tag[4];
char fmt_tag[4];
int fmt_length;
short audio_format;
short num_channels;
int sample_rate;
int byte_rate;
short block_align;
short bits_per_sample;
char data_tag[4];
int data_length;
};
FILE* target;
/*
* open wavfile and set the riff header
*/
FILE* wavfile_open()
{
// populate the header
struct wavfile_header header;
strncpy(header.riff_tag, "RIFF",4);
strncpy(header.wave_tag, "WAVE",4);
strncpy(header.fmt_tag, "fmt ",4);
strncpy(header.data_tag, "data",4);
header.riff_length = 0;
header.fmt_length = 16;
header.audio_format = 1;
header.num_channels = 1;
header.sample_rate = samples_per_second;
header.byte_rate = samples_per_second * (bits_per_sample / 8);
header.block_align = bits_per_sample / 8;
header.bits_per_sample = bits_per_sample;
header.data_length = 0;
FILE *file = fopen(output_name, "w+");
if(!file) return 0;
fwrite(&header, sizeof(header), 1, file);
fflush(file);
return file;
}
/*
* write to wavfile
*/
void wavfile_write(double* data, int length)
{
short* shortdata = (short*) malloc(sizeof(short) * length);
int i;
double sample;
for (i = 0; i < length; i++) {
sample = data[i] * 0.5; /// (DBL_MAX*0.01);
shortdata[i] = (short) (sample * SHRT_MAX * 0.5);
}
fwrite(shortdata, sizeof(short), length, target);
fflush(target);
written_samples += length;
free(shortdata);
}
/*
* close the open wavfile
*/
void wavfile_close()
{
int file_length = ftell(target);
int data_length = file_length - sizeof(struct wavfile_header);
fseek(target, sizeof(struct wavfile_header) - sizeof(int), SEEK_SET);
fwrite(&data_length, sizeof(data_length), 1, target);
int riff_length = file_length - 8;
fseek(target, 4, SEEK_SET);
fwrite(&riff_length, sizeof(riff_length), 1, target);
fclose(target);
}
/*
* Returns a random float within a range
*
* min: bottom end of range
* max: top end of range
*
* returns: random float
*/
double rangerandom(double min, double max)
{
double random = ((double) rand()) / (double) RAND_MAX;
double diff = max - min;
double r = random * diff;
return min + r;
}
int boolrandom()
{
return (rand() > (RAND_MAX / 2));
}
double interpolate(double items[], int points, int point)
{
return (((items[1] - items[0]) / points) * point) + items[0];
}
void create()
{
target = wavfile_open();
int seconds = 20;
int total_samples = samples_per_second * seconds;
int sample = 0;
int buffer_pos = 0;
int buffer_size = 4410;
double *buffer = (double*) malloc(sizeof(double) * buffer_size);
gutter_state *gs = gutter_init(4, 24, samples_per_second);
//gutter_randomisefilters(gs);
double* filterAutomation = malloc(sizeof(double) * gs->bankCount * gs->filterCount * 3 * 2);
int b, f, i, ai;
double val;
for (b = 0, ai=0; b < gs->bankCount; b++) {
for (f = 0; f < gs->filterCount; f++) {
i = b * gs->bankCount + f;
val = rangerandom(100, 2000);
filterAutomation[ai++] = val;
filterAutomation[ai++] = (boolrandom()) ? val : rangerandom(100, 2000);
val = rangerandom(0.3, 1);
filterAutomation[ai++] = val;
filterAutomation[ai++] = (boolrandom()) ? val : rangerandom(0.3, 1);
val = rangerandom(20, 200);
filterAutomation[ai++] = val;
filterAutomation[ai++] = (boolrandom()) ? val : rangerandom(20, 200);
}
}
double gamma[2] = { rangerandom(2, 10), rangerandom(2, 10) };
double omega[2] = { rangerandom(0.2, 1), rangerandom(0.2, 1) };
double c[2] = { rangerandom(0.2, 2), rangerandom(0.2, 2) };
double dt[2] = { rangerandom(100, 10000), rangerandom(100, 10000) };
double singleGain[2] = { rangerandom(0.2, 0.7), rangerandom(0.2, 0.7) };
gs->filtersOn = 1;
gs->smoothing = 1;
gs->distortionMethod = 2;
gs->omega = rangerandom(0.3, 0.9);
gs->c = rangerandom(0.5, 0.9);
gs->dt = rangerandom(100, 500);
gutter_randomisefilters(gs);
for (sample = 0; sample <= total_samples; sample ++) {
gs->gamma = interpolate(gamma, total_samples, sample);
//gs->omega = 0.8; //interpolate(omega, total_samples, sample);
//gs->c = 0.8; //interpolate(c, total_samples, sample);
//gs->dt = 300; //interpolate(dt, total_samples, sample);
gs->singleGain = 0.8; //interpolate(singleGain, total_samples, sample);
for (b = 0, ai = 0; b < gs->bankCount; b++) {
for (f = 0; f < gs->filterCount; f++, ai=ai+6) {
i = b * gs->bankCount + f;
gs->filterFreqs[i] = interpolate(filterAutomation + ai, total_samples, sample);
gs->gains[i] = interpolate(filterAutomation + ai + 2, total_samples, sample);
gs->Q[i] = interpolate(filterAutomation + ai + 4, total_samples, sample);
}
}
gutter_calccoeffs(gs);
buffer[buffer_pos] = gutter_process(gs);
if (buffer_pos == buffer_size - 1) {
buffer_pos = 0;
wavfile_write(buffer, buffer_size);
} else {
buffer_pos ++;
}
// randomise filters every second
if (sample % samples_per_second == 0) {
//gutter_randomisefilters(gs);
}
}
free(buffer);
free(filterAutomation);
gutter_cleanup(gs);
wavfile_close();
}
int main()
{
// random seed from time
srand((unsigned int) time(NULL));
// generate the file
create();
return 0;
}
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