Griffin PowerMater as FX knob - Mixxx HID controller mappings

griffin-powermate-fx-knob.hid.js

const GPM = { friction: 10, deck: 0 };

GPM.init = function (id) {
  GPM.controller = new HIDController();
  GPM.id = id;
  GPM.controller.activeDeck = 1;
  GPM.registerInputPackets();
  GPM.registerOutputPackets();
  GPM.registerCallbacks();
};

GPM.shutdown = function () {
  GPM.controller.close();
};

GPM.registerOutputPackets = function () {
  const packet = new HIDPacket("out");

  packet.addControl("hid", "led", 0, "B");

  GPM.controller.registerOutputPacket(packet);
};

GPM.registerInputPackets = function () {
  const packet = new HIDPacket("control");

  packet.addControl("hid", "button", 0, "B", 0x01);
  packet.addControl("hid", "wheel", 1, "b");
  packet.setMinDelta("hid", "wheel", undefined);

  this.controller.registerInputPacket(packet);
};

GPM.incomingData = function (data, length) {
  GPM.controller.parsePacket(data, length);
};

GPM.registerCallbacks = function (id) {
  const controller = GPM.controller;

  controller.setCallback("control", "hid", "button", GPM.button);
  controller.setCallback("control", "hid", "wheel", GPM.wheel);
};

GPM.toggleLED = function (on) {
  const packet = GPM.controller.getOutputPacket("out");
  const field = packet.getField("hid", "led");

  field.value = on ? 255 : 0;

  packet.send();
};

GPM.updateLED = function () {
  GPM.toggleLED(GPM.deck === 0);
};

GPM.changeDeck = function () {
  GPM.deck = GPM.deck === 1 ? 0 : 1;
  GPM.updateLED();
};

GPM.button = function (field) {
  field.value === 1 && GPM.changeDeck();
};

GPM.getActiveFxID = function () {
  const index = GPM.deck + 1;

  return "[EffectRack1_EffectUnit" + index + "]";
};

GPM.wheel = function (field) {
  const fxID = GPM.getActiveFxID();
  const current = engine.getValue(fxID, "mix");
  const shift = field.value / GPM.friction;

  engine.setValue(fxID, "mix", current + shift);
  field.value = 0;
};

griffin-powermate-fx-knob.hid.xml

<?xml version='1.0' encoding='utf-8'?>
<MixxxControllerPreset schemaVersion="1" mixxxVersion="1.11+">
    <info>
        <name>Griffin Powermate - FX knob</name>
        <author>Tancredi Trugenberger</author>
        <description>Griffin Powermate HID mapping to control the effects main knobs across 2 decks (press to change active deck)</description>
    </info>
    <controller id="Griffin">
        <scriptfiles>
            <file filename="common-hid-packet-parser.js" functionprefix=""/>
            <file filename="griffin-powermate-fx-knob.hid.js" functionprefix="GPM"/>
        </scriptfiles>
    </controller>
</MixxxControllerPreset>