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Diffstat (limited to 'examples/example1.c')
| -rw-r--r-- | examples/example1.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/examples/example1.c b/examples/example1.c new file mode 100644 index 0000000..f827ca7 --- /dev/null +++ b/examples/example1.c @@ -0,0 +1,226 @@ +#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; +} |