64 lines
1.7 KiB
JavaScript
64 lines
1.7 KiB
JavaScript
/**
|
|
* Credits to:
|
|
* https://codepen.io/jakealbaugh/pen/jvQweW
|
|
*/
|
|
|
|
// UPDATE: there is a problem in chrome with starting audio context
|
|
// before a user gesture. This fixes it.
|
|
var started = false;
|
|
var spectro_button = document.getElementById('spectro-button');
|
|
spectro_button.addEventListener('click', () => {
|
|
if (started) return;
|
|
started = true;
|
|
console.log("starting spectro");
|
|
initialize();
|
|
})
|
|
|
|
function initialize() {
|
|
const CVS = document.getElementById('spectro-canvas');
|
|
const CTX = CVS.getContext('2d');
|
|
const W = CVS.width = window.innerWidth;
|
|
const H = CVS.height = window.innerHeight;
|
|
|
|
const ACTX = new AudioContext();
|
|
const ANALYSER = ACTX.createAnalyser();
|
|
|
|
ANALYSER.fftSize = 4096;
|
|
|
|
navigator.mediaDevices
|
|
.getUserMedia({ audio: true })
|
|
.then(process);
|
|
|
|
function process(stream) {
|
|
const SOURCE = ACTX.createMediaStreamSource(stream);
|
|
SOURCE.connect(ANALYSER);
|
|
const DATA = new Uint8Array(ANALYSER.frequencyBinCount);
|
|
const LEN = DATA.length;
|
|
const h = H / LEN;
|
|
const x = W - 1;
|
|
CTX.fillStyle = 'hsl(280, 100%, 10%)';
|
|
CTX.fillRect(0, 0, W, H);
|
|
|
|
loop();
|
|
|
|
function loop() {
|
|
window.requestAnimationFrame(loop);
|
|
let imgData = CTX.getImageData(1, 0, W - 1, H);
|
|
CTX.fillRect(0, 0, W, H);
|
|
CTX.putImageData(imgData, 0, 0);
|
|
ANALYSER.getByteFrequencyData(DATA);
|
|
for (let i = 0; i < LEN; i++) {
|
|
let rat = DATA[i] / 255;
|
|
let hue = Math.round((rat * 120) + 280 % 360);
|
|
let sat = '100%';
|
|
let lit = 10 + (70 * rat) + '%';
|
|
CTX.beginPath();
|
|
CTX.strokeStyle = `hsl(${hue}, ${sat}, ${lit})`;
|
|
CTX.moveTo(x, H - (i * h));
|
|
CTX.lineTo(x, H - (i * h + h));
|
|
CTX.stroke();
|
|
}
|
|
}
|
|
}
|
|
}
|