scsynth-metro.js

"use strict";

// $ scsynth -u 57110

const dgram = require("dgram");
const OSC = require("osc-msg");
const colors = require("colors");
const SynthDefEncoder = require("synthdef-json-encoder");

const SC_PORT = 57110;
const socket = dgram.createSocket("udp4");

socket.on("message", (buffer) => {
  const msg = OSC.decode(buffer);
  global.console.log(colors.yellow(`<< ${ JSON.stringify(msg) }`));
});

/**
 * JS時間をOSC-timetagに変換する
 * @param {number} time
 * @return {number[]}
 */
function fromTime(time) {
  time = time + 2208988800;

  var hi = time >>> 0;
  var lo = ((time - hi) * 4294967296) >>> 0;

  return [ hi, lo ];
}

/**
 * scsynthにOSCメッセージを送信する
 * @param {object} msg
 */
function send(msg) {
  const buffer = OSC.encode(msg);
  socket.send(buffer, SC_PORT, "127.0.0.1", () => {
    global.console.log(colors.cyan(`>> ${ JSON.stringify(msg) }`));
  });
}

/**
 * scsynthにOSCメッセージをタイムタグ付きで送信する
 * @param {number} time
 * @param {object} msg
 */
function sendAt(time, msg) {
  const timetag = fromTime(time);
  const buffer = OSC.encode({ timetag, elements: [ msg ] });
  socket.send(buffer, SC_PORT, "127.0.0.1", () => {
    global.console.log(colors.cyan(`>> ${ JSON.stringify(msg) }`));
  });
}

////////////////////////////////////////////////////////////////////////////////
// scsynth向けOSCメッセージ

function dumpOSC(code) {
  return {
    address: "/dumpOSC",
    args: [ { type: "integer", value: code|0 } ]
  };
}

function notify(code) {
  return {
    address: "/notify",
    args: [ { type: "integer", value: code|0 } ]
  };
}

function clearSched() {
  return {
    address: "/clearSched"
  };
}

function g_freeAll(nodeid) {
  return {
    address: "/g_freeAll",
    args: [ { type: "integer", value: nodeid|0 } ]
  };
}

function g_new(nodeid, action = 0, target = 0) {
  return {
    address: "/g_new",
    args: [
      { type: "integer", value: nodeid|0 },
      { type: "integer", value: action|0 },
      { type: "integer", value: target|0 },
    ]
  };
}

function d_recv(sdef) {
  return {
    address: "/d_recv",
    args: [ { type: "blob", value: sdef } ],
  };
}

function s_new(sdefname, nodeid, action = 0, target = 0, params=[]) {
  return {
    address: "/s_new",
    args: [
      { type: "string", value: sdefname },
      { type: "integer", value: nodeid|0 },
      { type: "integer", value: action|0 },
      { type: "integer", value: target|0 },
    ].concat(params.map((value, index) => {
      return { type: [ "integer", "float" ][index % 2], value };
    }))
  };
}

////////////////////////////////////////////////////////////////////////////////
// SynthDefの定義
// SynthDef(\beep, {|freq = 440, amp = 0.25|
//   var beep = SinOsc.ar(freq) * Line.kr(amp, 0, 0.25, doneAction: 2);
//   Out.ar(0, beep ! 2);
// });

const beep = SynthDefEncoder.encode({
  version: 1,
  name: "beep",
  paramValues: [ 440, 0.25 ],
  paramIndices: [
    { name: "freq", index: 0, length: 1 },
    { name: "amp" , index: 1, length: 1 },
  ],
  consts: [ 0, 0.25, 2 ],
  units: [
    [ "Control"     , 1, 0, [                                            ], [ 1, 1 ] ],
    [ "SinOsc"      , 2, 0, [ [  0, 0 ], [ -1, 0 ]                       ], [ 2    ] ],
    [ "Line"        , 1, 0, [ [  0, 1 ], [ -1, 0 ], [ -1, 1 ] ,[ -1, 2 ] ], [ 1    ] ],
    [ "BinaryOpUGen", 2, 2, [ [  1, 0 ], [  2, 0 ]                       ], [ 2    ] ],
    [ "Out"         , 2, 0, [ [ -1, 0 ], [  3, 0 ], [  3, 0 ]            ], [      ] ],
  ]
});

////////////////////////////////////////////////////////////////////////////////
// overtoneっぽいAPI

function metronome(bpm) {
  const metroStart = Date.now() / 1000;
  const beatTicks = 60 / bpm;

  return beat => metroStart + beat * beatTicks;
}

function at(time, func, args = []) {
  const timeDelta = time - (Date.now() / 1000);
  const timerFunc = timeDelta <= 0.1 ? setImmediate : setTimeout;

  timerFunc(() => func(...args), timeDelta * 1000);
}

////////////////////////////////////////////////////////////////////////////////
// メイン

function main() {
  let synthId = 16777216;

  const metro = metronome(120 / 4);

  function player(beat = 0) {
    const t0 = metro(beat + 0.00);
    const t1 = metro(beat + 0.25);
    const t2 = metro(beat + 0.50);
    const t3 = metro(beat + 0.75);
    const t4 = metro(beat + 1.00);

    at(t0, () => sendAt(t0, s_new("beep", synthId++, 0, 1, [ 0, 1760, 1, 0.50 ])));
    at(t1, () => sendAt(t1, s_new("beep", synthId++, 0, 1, [ 0,  440, 1, 0.25 ])));
    at(t2, () => sendAt(t2, s_new("beep", synthId++, 0, 1, [ 0,  440, 1, 0.25 ])));
    at(t3, () => sendAt(t3, s_new("beep", synthId++, 0, 1, [ 0,  440, 1, 0.25 ])));
    at(t4, player, [ beat + 1 ]);
  }

  // scsynthの初期化
  send(dumpOSC(1));
  send(notify(1));
  send(g_freeAll(0));
  send(clearSched());
  send(g_new(1));

  // SynthDef[beep]を送信
  send(d_recv(beep));

  player();
}

main();