71 lines
1.9 KiB
JavaScript
71 lines
1.9 KiB
JavaScript
var midiLoaded = false;
|
|
function loadMIDI() {
|
|
MIDI.loadPlugin({
|
|
soundfontUrl: "/assets/trading-in-the-rain/soundfont/",
|
|
instrument: "acoustic_grand_piano",
|
|
onprogress: (state, progress) => {
|
|
console.log("MIDI loading...", progress*100, "%");
|
|
},
|
|
onsuccess: () => {
|
|
console.log("MIDI is ready to be used");
|
|
MIDI.setVolume(0, 127);
|
|
midiLoaded = true;
|
|
},
|
|
});
|
|
}
|
|
|
|
function MusicBox(priceDist, volumeDist) {
|
|
this.priceDist = priceDist;
|
|
this.volumeDist = volumeDist;
|
|
|
|
// clamp the keyboard so we're not using the very low notes, they don't sound
|
|
// good.
|
|
const noteRange = {
|
|
//low: 21,
|
|
//low: 36, // C2
|
|
low: 60, // C4, middle C
|
|
high: 108
|
|
};
|
|
|
|
|
|
function makeScale(tpl) {
|
|
tplObj = {};
|
|
for (i in tpl) {
|
|
tplObj[tpl[i]] = true;
|
|
}
|
|
|
|
let scale = [];
|
|
for (let note=noteRange.low; note<=noteRange.high; note++) {
|
|
let key = MIDI.noteToKey[note].replace(/\d+$/, "");
|
|
if (tplObj[key]) {
|
|
scale.push(note);
|
|
}
|
|
}
|
|
return scale;
|
|
}
|
|
|
|
//this.scale = makeScale(["C", "D", "E", "F", "G", "A", "B"]); // cMajor
|
|
//this.scale = makeScale(["D", "E", "Gb", "G", "A", "Db"]); //dMajor
|
|
//this.scale = makeScale(["C", "D", "E", "G", "A"]); // cMajor pentatonic
|
|
this.scale = makeScale(["F", "G", "A", "C", "D"]); // fMajor pentatonic
|
|
|
|
this.playNote = (note, holdFor) => {
|
|
if (!midiLoaded) return;
|
|
let velocity = 127;
|
|
MIDI.noteOn(0, note, velocity, 0);
|
|
MIDI.noteOff(0, note, holdFor);
|
|
};
|
|
|
|
this.playTrades = (trades) => {
|
|
if (this.priceDist.length == 0) return;
|
|
for (let i in trades) {
|
|
let noteIdx = this.priceDist.distribute(trades[i].price, 0, this.scale.length-1);
|
|
noteIdx = Math.round(noteIdx);
|
|
|
|
let holdFor = 0.25 + this.volumeDist.distribute(trades[i].volume, 0, 1.75);
|
|
let note = this.scale[noteIdx];
|
|
this.playNote(note, holdFor);
|
|
}
|
|
};
|
|
}
|