Generate the rick roll animation for the Factorio screen!

factorioRickRoll.js

const Blueprint = require('factorio-blueprint');
const PNG = require('png-js');

const inputs = Object.keys(Blueprint.getEntityData()).filter(key => !Blueprint.getEntityData()[key].combinator).slice(0, 60);
const bp = new Blueprint();

const FRAMES = 4230; // Number of images I had
const COL = 30; // Max height = COL * 4 or something
const LEFT = true; // Change so you can get the left and the right side

let prevPole = null;
for (let y = 0; y < COL/2; y++) {
  for (let x = 0; x < FRAMES/COL/4; x++) {
    const X = (y % 2 == 1 ? Math.ceil(FRAMES/COL/4) - x - 1 : x)*8 + 3;
    const Y = y*7 + 3;

    const pole = bp.createEntity('medium_electric_pole', { x: X, y: Y });
    if (prevPole) {
      pole.connect(prevPole);
      pole.connect(prevPole, null, null, 'green');
    }
    prevPole = pole;
  }
}

for (let i = 0; i < FRAMES; i++) {
  ((index) => {
    PNG.decode('./img/'+(index+1)+'.png', pixels => {
      frame(index, pixels);
    });
  })(i);
}

const THRESHHOLD = 256*3/2;

function parsePixels(pixels, left) {
  const ret = {};
  for (let y = 0; y < 60; y++) {
    const item = inputs[y];
    ret[item] = 0;
    for (let x = (left ? 0 : 30); x < (left ? 30 : 60); x++) {
      const index = y*240+x*4;
      const total = pixels[index]+pixels[index+1]+pixels[index+2];
      if (total > THRESHHOLD) ret[item] += Math.abs(1 << (left ? 29 - x : x - 30));
    }
  }
  return ret;
}

function frame(id, pixels) {
  const data = parsePixels(pixels, LEFT);
  const keys = Object.keys(data);
  let prev = null;

  const mainX = Math.floor(id/COL);
  const mainY = id % COL;

  const X = mainX*2;
  const Y = mainY*4 - Math.floor(mainY/2);

  const poleX = Math.floor(mainX/4)*8 + 3;
  const poleY = Math.floor(mainY/2)*7 + 3;

  for (let i = 0; i < 4; i++) {
    const myX = X + (i % 2 == 0 ? 0 : 1);
    const myY = Y + (i < 2 ? 1 : 2);
    const ent = bp.createEntity('constant_combinator', { x: myX, y: myY });
    for (let j = 0; j < 15; j++) {
      ent.setFilter(j+1, keys[i*15 + j], data[keys[i*15 + j]]);
    }
    if (prev) ent.connect(prev);
    prev = ent;
  }

  bp.createEntity('decider_combinator', { x: X, y: Y, direction: 2 })
    .connect(prev, 'in', null)
    .connect(bp.findEntity({ x: poleX, y: poleY }), 'out', null, 'red')
    .connect(bp.findEntity({ x: poleX, y: poleY }), 'in', null, 'green')
    .setCondition({
      left: 'signal_0',
      operator: '=',
      right: id+1,
      out: 'signal_everything'
    });

  done();
}

var framesDone = 0;
function done() {
  framesDone++;
  if (framesDone == FRAMES) {
    bp.center();
    console.log(bp.encode());
  }
}