Merge branch 'master' into production

app/lib/world/rand.coffee

@@ -32,4 +32,8 @@ class Rand
   rand2: (min, max) =>
     min + @rand max - min
 
+  # return an array of numbers from 0 to n-1, shuffled
+  randArray: (n) =>
+    _.shuffle [0...n]
+
 module.exports = Rand

app/lib/world/thang.coffee

@@ -1,23 +1,42 @@
 ThangState = require './thang_state'
 {thangNames} = require './names'
 {ArgumentError} = require './errors'
+Rand = require './rand'
 
 module.exports = class Thang
   @className: "Thang"
+  @random = new Rand
+
+  # Random ordering for each sprite name
+  @ordering: (spriteName) ->
+    Thang.orders ?= {}
+    names = thangNames[spriteName]
+    if names
+      len = names.length
+      array = Thang.orders[spriteName]
+      unless array?
+        array = @random.randArray len
+        Thang.orders[spriteName] = array
+    else
+      array = []
+    array
+
   @nextID: (spriteName) ->
     Thang.lastIDNums ?= {}
     names = thangNames[spriteName]
+    order = @ordering spriteName
     if names
       lastIDNum = Thang.lastIDNums[spriteName]
       idNum = (if lastIDNum? then lastIDNum + 1 else 0)
       Thang.lastIDNums[spriteName] = idNum
-      id = names[idNum % names.length]
+      id = names[order[idNum % names.length]]
       if idNum >= names.length
         id += Math.floor(idNum / names.length) + 1
     else
       Thang.lastIDNums[spriteName] = if Thang.lastIDNums[spriteName]? then Thang.lastIDNums[spriteName] + 1 else 0
       id = spriteName + (Thang.lastIDNums[spriteName] or '')
     id
+    
   @resetThangIDs: -> Thang.lastIDNums = {}
 
   constructor: (@world, @spriteName, @id) ->
@@ -137,4 +156,4 @@ module.exports = class Thang
     for prop, val of o.finalState
       # TODO: take some (but not all) of deserialize logic from ThangState to handle other types
       t[prop] = val
-    t
+    t

app/lib/world/world.coffee

@@ -245,11 +245,17 @@ module.exports = class World
   addScripts: (scripts...) ->
     @scripts = (@scripts ? []).concat scripts
 
+  addTrackedProperties: (props...) ->
+    @trackedProperties = (@trackedProperties ? []).concat props
+
   serialize: ->
     # Code hotspot; optimize it
     if @frames.length < @totalFrames then worldShouldBeOverBeforeSerialization
     [transferableObjects, nontransferableObjects] = [0, 0]
-    o = {name: @name, totalFrames: @totalFrames, maxTotalFrames: @maxTotalFrames, frameRate: @frameRate, dt: @dt, victory: @victory, userCodeMap: {}, showCoordinates: @showCoordinates, showGrid: @showGrid, showPaths: @showPaths, indieSprites: @indieSprites}
+    o = {name: @name, totalFrames: @totalFrames, maxTotalFrames: @maxTotalFrames, frameRate: @frameRate, dt: @dt, victory: @victory, userCodeMap: {}}
+
+    o[prop] = @[prop] for prop in @trackedProperties or []
+    
     for thangID, methods of @userCodeMap
       serializedMethods = o.userCodeMap[thangID] = {}
       for methodName, method of methods