Tutorial: Play Sine Wave (OCaml)

Playing a Sine Wave in OCaml

The main explanation is on the C++ page playing a sine wave.
Here we only provide the equivalent code for the OCaml programming language:

module BA = Bigarray
module BA1 = Bigarray.Array1

let () =
  let samples = 44100 in
  let sample_rate = 44100 in
  let amplitude = 30000. in
  
  let raw = BA1.create BA.int16_signed BA.c_layout samples in

  let two_pi = 6.28318 in
  let increment = 440.0 /. 44100.0 in
  let x = ref 0.0 in

  for i = 0 to samples - 1 do
    raw.{i} <- truncate (amplitude *. sin (!x *. two_pi));
    x := !x +. increment;
  done;
  
  let buffer = SFSoundBuffer.loadFromSamples raw 1 sample_rate in

  let snd = SFSound.create () in
  SFSound.setBuffer snd buffer;
  SFSound.setLoop snd true;
  SFSound.play snd;
  while true do
    SFTime.sleep (SFTime.of_milliseconds 100_l);
  done

To run it in script mode you can add this at the beginning of the file:

#directory "+sfml"
#load "bigarray.cma"
#load "sfml_system.cma"
#load "sfml_audio.cma"

To compile to native code:

ocamlopt -I +sfml bigarray.cmxa sfml_system.cmxa sfml_audio.cmxa sin.ml -o sin.exe