visualizer.js

#!/usr/bin/env node

var convert = require('color-convert');
var OPC = new require('../fadecandy/examples/node/opc')
var client = new OPC('localhost', 7890);

// This is set in the CAVA config file
const bars = 100;

const frame = [];

const visualizers = [
    [0, 250]
];

let hue = 0;

function draw([start, end, rangeStart = 0, rangeEnd = 100]) {
    const barPixelRatio = (rangeEnd - rangeStart) / (end - start);

    for (var pixel = 0; pixel < end - start; pixel++) {
        const frameIndex = Math.floor(pixel * barPixelRatio + rangeStart);
        const saturation = 100;
        const lightness = frame[0][frameIndex] * (100 / 255);
        client.setPixel(pixel + start, ...convert.hsl.rgb(hue, saturation, lightness));
    }
    client.writePixels();
}

setInterval(() => {
    hue += 1;
    if (hue > 360) {
        hue = 0;
    }
}, 1000)

process.stdin.setEncoding('utf8');

let str = '';
process.stdin.on('readable', () => {
    let chunk;

    // Use a loop to make sure we read all available data.
    while ((chunk = process.stdin.read()) !== null) {
        str += chunk;

        const frameEnd = str.indexOf('@');

        if (frameEnd > 0) {
            displayFrame(str.substring(0, frameEnd));
            str = str.substring(frameEnd + 1);
        }
    }
});

function displayFrame(f) {
    frame.pop();
    frame.push(f.split(';'));
    visualizers.forEach(draw);
}

process.stdin.on('end', () => {
    console.log('end');
});