rng class..

common/GameCommon.js

@@ -7,9 +7,10 @@ function exists(gameId) {
   return (!!GAMES[gameId]) || false
 }
 
-function createGame(id, puzzle, players, sockets, evtInfos) {
+function createGame(id, rng, puzzle, players, sockets, evtInfos) {
   return {
     id: id,
+    rng: rng,
     puzzle: puzzle,
     players: players,
     sockets: sockets,
@@ -31,8 +32,8 @@ function createPlayer(id, ts) {
   }
 }
 
-function newGame({id, puzzle, players, sockets, evtInfos}) {
+function newGame({id, rng, puzzle, players, sockets, evtInfos}) {
-  const game = createGame(id, puzzle, players, sockets, evtInfos)
+  const game = createGame(id, rng, puzzle, players, sockets, evtInfos)
   setGame(id, game)
   return game
 }

common/Rng.js

@@ -0,0 +1,27 @@
+export class Rng {
+  constructor(seed) {
+    this.rand_high = seed || 0xDEADC0DE
+    this.rand_low = seed ^ 0x49616E42
+  }
+
+  random (min, max) {
+    this.rand_high = ((this.rand_high << 16) + (this.rand_high >> 16) + this.rand_low) & 0xffffffff;
+    this.rand_low = (this.rand_low + this.rand_high) & 0xffffffff;
+    var n = (this.rand_high >>> 0) / 0xffffffff;
+    return (min + n * (max-min+1))|0;
+  }
+
+  static serialize (rng) {
+    return {
+      rand_high: rng.rand_high,
+      rand_low: rng.rand_low
+    }
+  }
+
+  static unserialize (rngSerialized) {
+    const rng = new Rng(0)
+    rng.rand_high = rngSerialized.rand_high
+    rng.rand_low = rngSerialized.rand_low
+    return rng
+  }
+}

common/Util.js

@@ -1,11 +1,20 @@
+import { Rng } from './Rng.js'
+
 // get a unique id
 export const uniqId = () => Date.now().toString(36) + Math.random().toString(36).substring(2)
 
 // get a random int between min and max (inclusive)
-export const randomInt = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min
+export const randomInt = (
+  /** @type Rng */ rng,
+  min,
+  max
+) => rng.random(min, max)
 
 // get one random item from the given array
-export const choice = (array) => array[randomInt(0, array.length - 1)]
+export const choice = (
+  /** @type Rng */ rng,
+  array
+) => array[randomInt(rng, 0, array.length - 1)]
 
 export const throttle = (fn, delay) => {
   let canCall = true
@@ -21,11 +30,14 @@ export const throttle = (fn, delay) => {
 }
 
 // return a shuffled (shallow) copy of the given array
-export const shuffle = (array) => {
+export const shuffle = (
+  /** @type Rng */ rng,
+  array
+) => {
   let arr = array.slice()
   for (let i = 0; i <= arr.length - 2; i++)
   {
-    const j = randomInt(i, arr.length -1);
+    const j = randomInt(rng, i, arr.length -1);
     const tmp = arr[i];
     arr[i] = arr[j];
     arr[j] = tmp;

game/Fireworks.js

@@ -1,4 +1,5 @@
-import Util from './../common/Util.js'
+import { Rng } from '../common/Rng.js'
+import Util from '../common/Util.js'
 
 let minVx = -10
 let deltaVx = 20
@@ -17,22 +18,22 @@ const explosionDividerFactor = 10
 const nBombs = 1
 const percentChanceNewBomb = 5
 
-function color() {
+function color(/** @type Rng */ rng) {
-  const r = Util.randomInt(0, 255)
+  const r = Util.randomInt(rng, 0, 255)
-  const g = Util.randomInt(0, 255)
+  const g = Util.randomInt(rng, 0, 255)
-  const b = Util.randomInt(0, 255)
+  const b = Util.randomInt(rng, 0, 255)
   return 'rgba(' + r + ',' + g + ',' + b + ', 0.8)'
 }
 
 // A Bomb. Or firework.
 class Bomb {
-  constructor() {
+  constructor(/** @type Rng */ rng) {
     this.radius = bombRadius
     this.previousRadius = bombRadius
     this.explodingDuration = explodingDuration
     this.hasExploded = false
     this.alive = true
-    this.color = color()
+    this.color = color(rng)
 
     this.px = (window.innerWidth / 4) + (Math.random() * window.innerWidth / 2)
     this.py = window.innerHeight
@@ -124,8 +125,9 @@ class Particle {
 }
 
 class Controller {
-  constructor(canvas) {
+  constructor(canvas, /** @type Rng */ rng) {
     this.canvas = canvas
+    this.rng = rng
     this.ctx = this.canvas.getContext('2d')
     this.resize()
 
@@ -161,13 +163,13 @@ class Controller {
     this.particles = []
 
     for (let i = 0; i < nBombs; i++) {
-      this.readyBombs.push(new Bomb())
+      this.readyBombs.push(new Bomb(this.rng))
     }
   }
 
   update() {
     if (Math.random() * 100 < percentChanceNewBomb) {
-      this.readyBombs.push(new Bomb())
+      this.readyBombs.push(new Bomb(this.rng))
     }
 
     const aliveBombs = []

game/game.js

@@ -8,6 +8,7 @@ import Util from './../common/Util.js'
 import PuzzleGraphics from './PuzzleGraphics.js'
 import Game from './Game.js'
 import fireworksController from './Fireworks.js'
+import { Rng } from '../common/Rng.js'
 
 if (typeof GAME_ID === 'undefined') throw '[ GAME_ID not set ]'
 if (typeof WS_ADDRESS === 'undefined') throw '[ WS_ADDRESS not set ]'
@@ -324,6 +325,7 @@ async function main() {
   }
 
   const game = await Communication.connect(gameId, CLIENT_ID)
+  game.rng.obj = Rng.unserialize(game.rng.obj)
   Game.newGame(game)
 
   const bitmaps = await PuzzleGraphics.loadPuzzleBitmaps(game.puzzle)
@@ -338,7 +340,7 @@ async function main() {
   let finished = longFinished ? true : false
   const justFinished = () => !!(finished && !longFinished)
 
-  const fireworks = new fireworksController(canvas)
+  const fireworks = new fireworksController(canvas, game.rng.obj)
   fireworks.init(canvas)
 
   const ctx = canvas.getContext('2d')

package.json

@@ -8,5 +8,8 @@
     "multer": "^1.4.2",
     "twing": "^5.0.2",
     "ws": "^7.3.1"
+  },
+  "devDependencies": {
+    "jest": "^26.6.3"
   }
 }

scripts/tests

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+node --experimental-vm-modules node_modules/.bin/jest

server/Game.js

@@ -2,6 +2,7 @@ import fs from 'fs'
 import { createPuzzle } from './Puzzle.js'
 import GameCommon from './../common/GameCommon.js'
 import Util from './../common/Util.js'
+import { Rng } from '../common/Rng.js'
 
 const DATA_DIR = './../data'
 
@@ -28,6 +29,10 @@ function loadAllGames() {
     }
     GameCommon.newGame({
       id: game.id,
+      rng: {
+        type: game.rng ? game.rng.type : '_fake_',
+        obj: game.rng ? Rng.unserialize(game.rng.obj) : new Rng(),
+      },
       puzzle: game.puzzle,
       players: game.players,
       sockets: [],
@@ -38,9 +43,14 @@ function loadAllGames() {
 
 const changedGames = {}
 async function createGame(gameId, targetTiles, image) {
+  const rng = new Rng(gameId);
   GameCommon.newGame({
     id: gameId,
-    puzzle: await createPuzzle(targetTiles, image),
+    rng: {
+      type: 'Rng',
+      obj: rng,
+    },
+    puzzle: await createPuzzle(rng, targetTiles, image),
     players: {},
     sockets: [],
     evtInfos: {},
@@ -70,6 +80,10 @@ function persistChangedGames() {
       delete changedGames[game.id]
       fs.writeFileSync(`${DATA_DIR}/${game.id}.json`, JSON.stringify({
         id: game.id,
+        rng: {
+          type: game.rng.type,
+          obj: Rng.serialize(game.rng.obj),
+        },
         puzzle: game.puzzle,
         players: game.players,
       }))

server/Puzzle.js

@@ -1,6 +1,7 @@
 import sizeOf from 'image-size'
 import Util from './../common/Util.js'
 import exif from 'exif'
+import { Rng } from '../common/Rng.js'
 
 // cut size of each puzzle tile in the
 // final resized version of the puzzle image
@@ -34,7 +35,11 @@ async function getExifOrientation(imagePath) {
   })
 }
 
-async function createPuzzle(targetTiles, image) {
+async function createPuzzle(
+  /** @type Rng */ rng,
+  targetTiles,
+  image
+) {
   const imagePath = image.file
   const imageUrl = image.url
 
@@ -48,7 +53,7 @@ async function createPuzzle(targetTiles, image) {
   for (let i = 0; i < tiles.length; i++) {
     tiles[i] = { idx: i }
   }
-  const shapes = determinePuzzleTileShapes(info)
+  const shapes = determinePuzzleTileShapes(rng, info)
 
   let positions = new Array(info.tiles)
   for (let tile of tiles) {
@@ -100,7 +105,7 @@ async function createPuzzle(targetTiles, image) {
   }
 
   // then shuffle the positions
-  positions = Util.shuffle(positions)
+  positions = Util.shuffle(rng, positions)
 
   tiles = tiles.map(tile => {
     return Util.encodeTile({
@@ -167,7 +172,10 @@ async function createPuzzle(targetTiles, image) {
   }
 }
 
-function determinePuzzleTileShapes(info) {
+function determinePuzzleTileShapes(
+  /** @type Rng */ rng,
+  info
+) {
   const tabs = [-1, 1]
 
   const shapes = new Array(info.tiles)
@@ -175,9 +183,9 @@ function determinePuzzleTileShapes(info) {
     let coord = Util.coordByTileIdx(info, i)
     shapes[i] = {
       top: coord.y === 0 ? 0 : shapes[i - info.tilesX].bottom * -1,
-      right: coord.x === info.tilesX - 1 ? 0 : Util.choice(tabs),
+      right: coord.x === info.tilesX - 1 ? 0 : Util.choice(rng, tabs),
       left: coord.x === 0 ? 0 : shapes[i - 1].right * -1,
-      bottom: coord.y === info.tilesY - 1 ? 0 : Util.choice(tabs),
+      bottom: coord.y === info.tilesY - 1 ? 0 : Util.choice(rng, tabs),
     }
   }
   return shapes.map(Util.encodeShape)

server/index.js

@@ -10,6 +10,7 @@ import Game from './Game.js'
 import twing from 'twing'
 import bodyParser from 'body-parser'
 import v8 from 'v8'
+import { Rng } from '../common/Rng.js'
 
 const allImages = () => [
   ...fs.readdirSync('./../data/uploads/').map(f => ({
@@ -130,9 +131,14 @@ wss.on('message', async ({socket, data}) => {
         Game.addPlayer(gameId, clientId)
         Game.addSocket(gameId, socket)
         const game = Game.get(gameId)
+        console.log(gameId, game)
         notify(
           [Protocol.EV_SERVER_INIT, {
             id: game.id,
+            rng: {
+              type: game.rng.type,
+              obj: Rng.serialize(game.rng.obj),
+            },
             puzzle: game.puzzle,
             players: game.players,
             sockets: [],

tests/Rng.test.js

@@ -0,0 +1,23 @@
+import { Rng } from '../common/Rng'
+
+test('random should give same results', () => {
+  const rng = new Rng(1337)
+  const rng2 = new Rng(1337)
+  for (let i = 0; i < 100; i++) {
+    expect(rng.random()).toBe(rng2.random())
+  }
+})
+
+test('should be serializable/deserializable', () => {
+  const rng = new Rng(1337)
+  // do some randoms, so that it doesnt start at 'after init'
+  for (let i = 0; i < 100; i++) {
+    rng.random()
+  }
+
+  const rng2 = Rng.unserialize(Rng.serialize(rng))
+
+  for (let i = 0; i < 100; i++) {
+    expect(rng.random()).toBe(rng2.random())
+  }
+})