nes-ai/server/game.js

const SCREEN_WIDTH = 256;
const SCREEN_HEIGHT = 240;
const SAMPLE_REDUCTION = 4;

const EventEmitter = require('events')
const fs = require('fs')
const jsnes = require('jsnes')
const move = require('move-terminal-cursor')

const chunk = (a, l) => Array(Math.ceil(a.length / l)).fill().map((_, i) => (a.slice ? a.slice(i * l, i * l + l) : a.substr(i * l, i * l + 1)))
const sample = (a, n) => Array(Math.floor(a.length / n)).fill().map((_, i) => a[i * n])

class Game extends EventEmitter {
  constructor() {
    super()
    const rom = fs.readFileSync('./Super Mario Bros. (World).nes', 'binary')
    this.nes = new jsnes.NES({
      onFrame: this.onFrame.bind(this)
    })
    this.nes.loadROM(rom)
    this.frameCount = 0
    this.packetBuffer = new ArrayBuffer(256 * 4 + SCREEN_WIDTH * SCREEN_HEIGHT)
    this.paletteBuffer = new Uint32Array(this.packetBuffer)
    this.pixelBuffer = new Uint8ClampedArray(this.packetBuffer, 256 * 4)
    this.frameBuffer = new ArrayBuffer(SCREEN_WIDTH * SCREEN_HEIGHT * 4)
    this.screen32 = new Uint32Array(this.frameBuffer)
    this.nes.ppu.buffer = this.screen32
    this.frameBytes = new Uint8ClampedArray(this.frameBuffer)
  }

  onFrame(frameBuffer) {
//    if (this.frameCount++ % SAMPLE_REDUCTION) {
      const colorMap = new Map()
      for (let i = 0; i < 256; i++) {
        this.paletteBuffer[i] = this.nes.ppu.palTable.curTable[i]
        colorMap.set(this.nes.ppu.palTable.curTable[i], i)
      }
      for (let i = 0; i < this.screen32.length; i++) {
        this.pixelBuffer[i] = colorMap.get(this.screen32[i])
      }
      this.emit('frame', this.packetBuffer)
//    }
    

    // if (true) {//(frameCount++ % 32 === 0) {
    //   //move('toPos', {row: 1, col: 1})
    //   const lines = sample(chunk(frameBuffer, SCREEN_WIDTH), SAMPLE_REDUCTION)
    //   .map(line => sample(line, SAMPLE_REDUCTION))
    //   //console.log(lines.map(l => Buffer.from(l).toString('hex')).join('\n'))

    //   // console.log('\n\n\n' + chunk(Buffer.from(frameBuffer).toString('hex'), SCREEN_WIDTH * 2).join('\n'))
    // }
  }

  start() {
    if (!this.timer) this.timer = setInterval(() => this.nes.frame(), 1000 / 60)
  }

  stop() {
    if (this.timer) {
      clearInterval(this.timer)
      this.timer = null
    }
  }
}

module.exports = Game