initial commit

Author: Jason Belcher

.gitignore

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+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+node_modules

drum-machine.js

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+let player = require("play-sound")();
+
+// For each tick in a sequence this object will be checked
+// to determine what instruments need
+// to be triggered for the current tick.
+
+function DrumMachineState(id) {
+  this.id = id;
+  this.kick = {
+    on: false,
+    name: "kick",
+    location: "./samples/Deep House Drum Samples/bd_kick/bd_deephouser.wav"
+  };
+  this.clap = {
+    on: false,
+    name: "clap",
+    location: "./samples/Deep House Drum Samples/clap/clp_analogue.wav"
+  };
+  this.hat = {
+    on: false,
+    name: "hat",
+    location: "./samples/Deep House Drum Samples/hats/hat_analog.wav"
+  };
+  this.shaker = {
+    on: false,
+    name: "shaker",
+    location:
+      "./samples/Deep House Drum Samples/shaker_tambourine/shaker_bot.wav"
+  };
+  this.perc = {
+    on: false,
+    name: "perc",
+    location: "./samples/Deep House Drum Samples/percussion/prc_bongodrm.wav"
+  };
+  this.perc2 = {
+    on: false,
+    name: "perc2",
+    location: "./samples/Deep House Drum Samples/percussion/prc_congaz.wav"
+  };
+}
+
+DrumMachineState.prototype.getState = function(name) {
+  return this[name];
+};
+DrumMachineState.prototype.setState = function(name, on, volume) {
+  this[name].on = on;
+  this[name].volume = volume || 1;
+  this[name].name = name;
+};
+
+// dependency inject the drum machine state into sequencer
+function Sequencer(drumMachineState, length) {
+  this.drumMachineState = drumMachineState;
+  this.length = length;
+  this.sequence = [];
+}
+
+Sequencer.prototype.initSeq = function() {
+  for (let i = 0; i < this.length; i += 1) {
+    this.sequence.push(new this.drumMachineState(i + 1));
+  }
+
+  return this.sequence;
+};
+
+// drum machine player
+const dm = {
+  playingSeq: null,
+  playHead: 0,
+  tempo: 800,
+  setTempo: function(tempo, ticksPerBeat = 1) {
+    let ms;
+    switch (ticksPerBeat) {
+      case 1:
+        ms = 60000 / tempo;
+        break;
+      case 2:
+        ms = 30000 / tempo;
+        break;
+      case 4:
+        ms = 15000 / tempo;
+      default:
+        ms = 15000 / tempo;
+    }
+    this.tempo = ms;
+  },
+  start: function start(initializedSequence) {
+    this.playingSeq = setInterval(() => {
+      this.triggerSounds(initializedSequence[this.playHead]);
+      this.playHead++;
+      if (this.playHead === initializedSequence.length) {
+        this.playHead = 0;
+      }
+    }, this.tempo);
+  },
+  stop: function stop(m) {
+    if (m === undefined) {
+      clearInterval(this.playingSeq);
+    }
+    setTimeout(() => {
+      clearInterval(this.playingSeq);
+    }, m);
+  },
+  triggerSounds: function triggerSounds(dmState) {
+    for (let instrument in dmState) {
+      if (dmState.hasOwnProperty(instrument)) {
+        if (dmState[instrument].on) {
+          console.log(dmState.getState(instrument).location);
+          player.play(dmState.getState(instrument).location, {
+            afplay: ["-v", dmState.getState(instrument).volume]
+          });
+        }
+      }
+    }
+  }
+};
+
+const sequencer = new Sequencer(DrumMachineState, 8);
+const seq = sequencer.initSeq();
+
+seq[0].setState("kick", true, 1);
+seq[4].setState("kick", true, 0.8);
+seq[4].setState("clap", true);
+seq[2].setState("hat", true, 0.2);
+seq[6].setState("hat", true, 0.24);
+seq[0].setState("shaker", true, 0.2);
+seq[1].setState("shaker", true, 0.1);
+seq[2].setState("shaker", true, 0.2);
+seq[3].setState("shaker", true, 0.1);
+seq[4].setState("shaker", true, 0.2);
+seq[5].setState("shaker", true, 0.1);
+seq[6].setState("shaker", true, 0.2);
+seq[7].setState("shaker", true, 0.1);
+seq[1].setState("perc", true, 0.3);
+seq[4].setState("perc", true, 0.4);
+seq[5].setState("perc", true, 0.3);
+seq[2].setState("perc2", true, 0.3);
+seq[3].setState("perc2", true, 0.5);
+seq[7].setState("perc2", true, 0.25);
+
+dm.setTempo(127, 4);
+dm.start(seq);

package-lock.json

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+{
+  "name": "drum-machine-v0.1",
+  "version": "1.0.0",
+  "description": "",
+  "main": "drum-machine.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "play-sound": "^1.1.3"
+  }
+}