// drums ---------------------
sampler.get("hihat").start();
if([0,1,4,8,12].indexOf(idx) >= 0)
sampler.get("kick").start();
if([2,6,10,14].indexOf(idx) >= 0)
sampler.get("snare").start();
// synth -----------------------
// E♭, F, G, A♭, B♭, C, D
const chords = [
['Eb2','Gb3','Bb3','D4'], //I
['C2','Eb3','G3','Bb4'], //VI
['F2','Ab3','C3','Eb4'], //II
['Bb2','D3','F3','Ab4'] // V
];
let chordIndex = -1;
if(idx === 0) chordIndex = 0;
if(idx === 4) chordIndex = 1;
if(idx === 8) chordIndex = 2;
if(idx === 12) chordIndex = 3;
if(chordIndex >= 0)
{
polySynth.triggerAttackRelease(chords[chordIndex][0],'8n');
polySynth.triggerAttackRelease(chords[chordIndex][1],'16n', '+16n');
polySynth.triggerAttackRelease(chords[chordIndex][2],'16n', '+8n');
polySynth.triggerAttackRelease(chords[chordIndex][3],'16n', '+4n');
}