rpi-ws281x-native

rpi-ws281x-native.js

const NUM_LEDS = 64;
if (!context.ws281x) {
    context.ws281x = require('rpi-ws281x-native');
    
    context.finalArray = new Uint32Array(NUM_LEDS);
    
    context.ws281x.init(NUM_LEDS, {dmaNum: 10});
}

if (context.ws281x) {
    bufferToArray(msg.payload, NUM_LEDS);
    context.ws281x.render(context.finalArray);
}

function bufferToArray(buffer, numLeds){
    if (msg.source == 'canvas') {
        const rowLength = 8;
        for (let p = 0; p < numLeds; p++) {
            let rowNum = Math.floor(p/rowLength);
            // Si impair
            if (rowNum % 2 == 1) {
                context.finalArray[(2 * rowNum * rowLength) - p + rowLength - 1] = buffer.readUInt32LE(p*4);
            } else {
                context.finalArray[p] = buffer.readUInt32LE(p*4);
            }
        }
        return;
    }
    // For each LED
    for (var p = 0; p < numLeds; p++) {
        var pixel = Buffer.alloc(4);
        buffer.copy(pixel, 1, p*3, (p*3)+3);
        context.finalArray[p] = pixel.readUInt32BE(0);
    }
}