leds/lights.js

import ws281x from 'rpi-ws281x'
import * as fs from 'fs'

const cfg = JSON.parse(fs.readFileSync('./config.json'));

const fade_ticks = cfg.fade_ticks || 20;
var pixels = new Uint32Array(cfg.leds);
var pixel_cache = new Uint32Array(cfg.leds);
var next_pattern = new Uint32Array(cfg.leds);
var pattern = {}

function rgb_to_int(r, g, b) {
  let rgb = r;
  rgb = (rgb << 8) + g;
  rgb = (rgb << 8) + b;
  return rgb;
}
function int_to_rgb(int) {
  var r = (int >> 16) & 0xFF;
  var g = (int >> 8) & 0xFF;
  var b = (int) & 0xFF;
  return { r: r, g: g, b: b };
}

ws281x.configure({
  leds: cfg.leds || 300,
  brightness: cfg.brightness || 200,
  gpio: cfg.gpio || 18,
  stripType: cfg.type || 'grb'
});

export function set_pattern(pat) {
  pattern = pat
}

function tick_pattern() {
  // do the parsing stuff here
  console.log("TICKING PATTERN")

  for (let i = 0; i < cfg.leds; i++) {
    var r = Math.floor(Math.random() * 256)
    var g = Math.floor(Math.random() * 256);
    var b = Math.floor(Math.random() * 256);
    next_pattern[i] = rgb_to_int(r, g, b);
  }
}

export function tick() {
  var changed = false;
  for (let i = 0; i < cfg.leds; i++) {
    if (next_pattern[i] != pixels[i]) {
      if (next_pattern[i] == pixel_cache[i]) {
        console.log("INCONGRUENCE WITH " + i);
        pixels[i] = next_pattern[i];
      }
      else {
        changed = true;
        fade(i);
      }
    }
    else if (pixel_cache[i] != pixels[i]) {
      console.log("PATTERN NOT STORED " + i);
      pixel_cache[i] = pixels[i];
    }
  }
  if (!changed) {
    tick_pattern();
  }
  else {
    ws281x.render(pixels);
  }
  ws281x.sleep(cfg.sleep_time || 500);
}

function fade(index) {
  var original = int_to_rgb(pixel_cache[index]);
  var current = int_to_rgb(pixels[index]);
  var final = int_to_rgb(next_pattern[index]);
  var diff_r = final.r - original.r;
  var diff_cr = current.r - original.r;
  var diff_g = final.g - original.g;
  var diff_cg = current.g - original.g;
  var diff_b = final.b - original.b;
  var diff_cb = current.b - original.b;
  var sign_r = diff_r === Math.abs(diff_r) ? 1 : -1;
  var sign_g = diff_g === Math.abs(diff_g) ? 1 : -1;
  var sign_b = diff_b === Math.abs(diff_b) ? 1 : -1;
  console.log(`${diff_r} ${sign_r} ${diff_g} ${sign_g} ${diff_b} ${sign_b}`);
  var interval_r = sign_r * Math.ceil(Math.abs(diff_r) / fade_ticks);
  var interval_g = sign_g * Math.ceil(Math.abs(diff_g) / fade_ticks);
  var interval_b = sign_b * Math.ceil(Math.abs(diff_b) / fade_ticks);
  console.log(`t ${Math.abs(diff_r) / fade_ticks} ${Math.ceil(Math.abs(diff_r) / fade_ticks)}` +
    `${Math.abs(diff_g) / fade_ticks} ${Math.ceil(Math.abs(diff_g) / fade_ticks)}` +
    `${Math.abs(diff_b) / fade_ticks} ${Math.ceil(Math.abs(diff_b) / fade_ticks)}`);

  var current_tick_r = Math.floor(Math.abs(diff_cr / diff_r) * fade_ticks);
  var current_tick_g = Math.floor(Math.abs(diff_cg / diff_g) * fade_ticks);
  var current_tick_b = Math.floor(Math.abs(diff_cb / diff_b) * fade_ticks);
  if (diff_r == 0 ||
    current.r + interval_r >= final.r ||
    current_tick_r + 1 >= fade_ticks) {
    current.r = final.r;
    interval_r = 0;
    current_tick_r = fade_ticks;
  }
  if (diff_g == 0 ||
    current.g + interval_g >= final.g ||
    current_tick_g + 1 >= fade_ticks) {
    current.g = final.g;
    interval_g = 0;
    current_tick_g = fade_ticks;
  }
  if (diff_b == 0 ||
    current.b + interval_b >= final.b ||
    current_tick_b + 1 >= fade_ticks) {
    current.b = final.b;
    interval_b = 0;
    current_tick_b = fade_ticks;
  }

  if (current_tick_r + 1 >= fade_ticks &&
    current_tick_g + 1 >= fade_ticks &&
    current_tick_b + 1 >= fade_ticks) {
    console.log("FINISHED");
    pixel_cache[index] = next_pattern[index];
  }
  else {
    pixels[index] = rgb_to_int(current.r + interval_r,
      current.g + interval_g,
      current.b + interval_b);
    let prev = int_to_rgb(pixel_cache[index]);
    console.log(`${current_tick_r} ${current_tick_g} ${current_tick_b}: `
      + `CURRENT COLOR: ${current.r} ${current.g} ${current.b} NEW COLOR: ${current.r + interval_r} ${current.g + interval_g} ${current.b + interval_b} ` +
      `FINAL: ${final.r} ${final.g} ${final.b} ` +
      `\nINTERVAL: ${interval_r} ${interval_g} ${interval_b} ` +
      `PREVIOUS: ${prev.r} ${prev.g} ${prev.b}`);
  }
}