let audio = document.getElementById('audio');
let file_path = audio.src;

var sound;
var fft;

function preload() {
    sound = loadSound(audio.src);    
}

function setup() {
    createCanvas(500, 500);
    colorMode(HSB);
    angleMode(DEGREES);
    sound.play();
    fft = new p5.FFT(0.9, 128);
}

function draw() {
    background(0);
    var spectrum = fft.analyze();
    noStroke();
    translate(width / 2, height / 2);

    for (var i = 0; i < spectrum.length; i++) {
        var angle = map(i, 0, spectrum.length, 0, 360);
        var amp = spectrum[i];
        var r = map(amp, 0, 256, 20, 100);
        var x = r * cos(angle);
        var y = r * sin(angle);
        stroke(i, 255, 255);
        line(0, 0, x, y);
    }
}