chorus.c

Ugrás a fájl dokumentációjához.

 
#include <stdio.h>
#include <math.h>
#include "binary_streams.h"
 
typedef float sample_t;
 
enum
{
    SAMPLE_RATE = 44100,    
    N = SAMPLE_RATE / 10    
};
 
int main(void)
{
    double const f_vib = 2.0;   
    int const depth = 60;       
    long long int cnt = 0;
    int write = 0, read = N / 2;
 
    // reopen streams as binary
    binary_streams();
 
    sample_t circ_buffer[N][2] = {0};
 
    // read samples while possible
    while (fread(circ_buffer[write], sizeof(sample_t), 2, stdin) == 2)
    {
        // update read index with harmonically varying offset
        int r = read + sin(2.0 * M_PI * f_vib / SAMPLE_RATE * cnt++) * depth;
        if (r < 0)
            r += N;
 
        // read FIFO content and add to dry signal
        sample_t output[2];
        for (int c = 0; c < 2; ++c)
            output[c] = circ_buffer[r % N][c] + circ_buffer[read][c];
 
        // write to output
        fwrite(output, sizeof(sample_t), 2, stdout);
 
        // cyclic indexing
        write = (write + 1) % N;
        read = (read + 1) % N;
    }
 
    return 0;
}