Generate sine wave

generate-sine.c

#include <stdio.h>
#include <math.h>

#define NUMBER_OF_SAMPLES 4410      // for 44100 Hz sample rate and 10Hz min f.
#define MAX_VALUE         0xFFFFFF  // 24-bit samples
#define MID_VALUE         (MAX_VALUE/2)
#define DC_OFFSET         (MID_VALUE) // set to 0 for no offset

// Generates a wavetable (a single wavecycle) of a sine wave.
// compile: gcc -o generate-sine generate-sine.c
// usage: ./generate-sine | gnuplot > sine.png

int main(int argc, char *argv[])
{
  unsigned int i;
  float pi=3.141592;
  float phase=0.0;
  long int y;
  float w;
  long int sample;

  // gnuplot header
  printf("set terminal png size 4096, 2160\n");
  printf("plot '-'\n");

  w=2*pi;
  w/=NUMBER_OF_SAMPLES;

  for (i=0; i<NUMBER_OF_SAMPLES; i++) {
    y=MID_VALUE*sin(phase);
    phase+=w;

    sample=y+DC_OFFSET;
    printf("%ld\n", sample);
  }

  // gnuplot end
  printf("e\n");

  return 0;
}