Fixed a ton of memory leaks, but not all of them.

app/application.coffee

@@ -20,7 +20,7 @@ elementAcceptsKeystrokes = (el) ->
   # not radio, checkbox, range, or color
   return (tag is 'textarea' or (tag is 'input' and type in textInputTypes) or el.contentEditable in ["", "true"]) and not (el.readOnly or el.disabled)
 
-COMMON_FILES = ['/images/modal_background.png', '/images/level/code_palette_background.png']
+COMMON_FILES = ['/images/pages/base/modal_background.png', '/images/level/code_palette_background.png']
 preload = (arrayOfImages) ->
   $(arrayOfImages).each ->
     $('<img/>')[0].src = @

app/lib/God.coffee

@@ -3,7 +3,7 @@
 ## Uncomment to imitate IE9 (and in world_utils.coffee)
 #window.Worker = null
 #window.Float32Array = null
-# (except that we won't have included vendor_with_box2d.js, so Collision won't run, things won't move, etc.)
+# Also uncomment vendor_with_box2d.js in index.html if you want Collision to run and things to move.
 
 module.exports = class God
   @ids: ['Athena', 'Baldr', 'Crom', 'Dagr', 'Eris', 'Freyja', 'Great Gish', 'Hades', 'Ishtar', 'Janus', 'Khronos', 'Loki', 'Marduk', 'Negafook', 'Odin', 'Poseidon', 'Quetzalcoatl', 'Ra', 'Shiva', 'Thor', 'Umvelinqangi', 'Týr', 'Vishnu', 'Wepwawet', 'Xipe Totec', 'Yahweh', 'Zeus', '上帝', 'Tiamat', '盘古', 'Phoebe', 'Artemis', 'Osiris', "嫦娥", 'Anhur', 'Teshub', 'Enlil', 'Perkele', 'Aether', 'Chaos', 'Hera', 'Iris', 'Theia', 'Uranus', 'Stribog', 'Sabazios', 'Izanagi', 'Ao', 'Tāwhirimātea', 'Tengri', 'Inmar', 'Torngarsuk', 'Centzonhuitznahua', 'Hunab Ku', 'Apollo', 'Helios', 'Thoth', 'Hyperion', 'Alectrona', 'Eos', 'Mitra', 'Saranyu', 'Freyr', 'Koyash', 'Atropos', 'Clotho', 'Lachesis', 'Tyche', 'Skuld', 'Urðr', 'Verðandi', 'Camaxtli', 'Huhetotl', 'Set', 'Anu', 'Allah', 'Anshar', 'Hermes', 'Lugh', 'Brigit', 'Manannan Mac Lir', 'Persephone', 'Mercury', 'Venus', 'Mars', 'Azrael', 'He-Man', 'Anansi', 'Issek', 'Mog', 'Kos', 'Amaterasu Omikami', 'Raijin', 'Susanowo', 'Blind Io', 'The Lady', 'Offler', 'Ptah', 'Anubis', 'Ereshkigal', 'Nergal', 'Thanatos', 'Macaria', 'Angelos', 'Erebus', 'Hecate', 'Hel', 'Orcus', 'Ishtar-Deela Nakh', 'Prometheus', 'Hephaestos', 'Sekhmet', 'Ares', 'Enyo', 'Otrera', 'Pele', 'Hadúr', 'Hachiman', 'Dayisun Tngri', 'Ullr', 'Lua', 'Minerva']
@@ -25,17 +25,22 @@ module.exports = class God
     @createWorld()
 
   getAngel: ->
+    freeAngel = null
     for angel in @angels
-      return angel.enslave() unless angel.busy
+      if angel.busy
+        angel.abort()
+      else
+        freeAngel ?= angel
+    return freeAngel.enslave() if freeAngel
     maxedOut = @angels.length is @maxAngels
     if not maxedOut
       angel = new Angel @
       @angels.push angel
       return angel.enslave()
-    oldestAngel = {started: new Date(2099, 1, 1)}
-    for angel in @angels
-      oldestAngel = angel if angel.started < oldestAngel.started
-    oldestAngel.abort()
+    #oldestAngel = {started: new Date(2099, 1, 1)}
+    #for angel in @angels
+    #  oldestAngel = angel if angel.started < oldestAngel.started
+    #oldestAngel.abort()
     null
 
   angelInfinitelyLooped: (angel) ->
@@ -65,6 +70,13 @@ module.exports = class God
     else
       @worldWaiting = true
       return
+    console.log "about to post message", @getUserCodeMap(), @level, @firstWorld, @goalManager?.getGoals(), JSON.stringify({
+      worldName: @world.name
+      userCodeMap: @getUserCodeMap()
+      level: @level
+      firstWorld: @firstWorld
+      goals: @goalManager?.getGoals()
+    }).length
     angel.worker.postMessage {func: 'runWorld', args: {
       worldName: @world.name
       userCodeMap: @getUserCodeMap()
@@ -91,8 +103,11 @@ module.exports = class God
     Backbone.Mediator.publish('god:new-world-created', world: @world, firstWorld: @firstWorld, errorCount: errorCount, goalStates: @latestGoalStates)
     for scriptNote in @world.scriptNotes
       Backbone.Mediator.publish scriptNote.channel, scriptNote.event
+    @goalManager?.world = newWorld
     @firstWorld = false
     @testWorld = null
+    unless _.find @angels, 'busy'
+      @spells = null  # Don't hold onto old spells; memory leaks
 
   getUserCodeMap: ->
     userCodeMap = {}
@@ -171,6 +186,7 @@ class Angel
     @busy = true
     @started = new Date()
     @purgatoryTimer = setInterval @testWorker, @infiniteLoopIntervalDuration
+    @spawnWorker() unless @worker
     @
 
   free: ->
@@ -178,6 +194,8 @@ class Angel
     @started = null
     clearInterval @purgatoryTimer
     @purgatoryTimer = null
+    @worker.terminate()
+    @worker = null
     @
 
   abort: ->
@@ -186,8 +204,8 @@ class Angel
 
   terminate: =>
     @worker.terminate()
+    @worker = null
     return if @dead
-    @spawnWorker()
     @free()
     @god.angelAborted @
 
@@ -219,7 +237,9 @@ class Angel
           clearTimeout @abortTimeout
           @free()
           @god.angelAborted @
-          @worker.terminate() if @god.dead
+          if @god.dead
+            @worker.terminate()
+            @worker = null
         when 'reportIn'
           clearTimeout @condemnTimeout
         else

app/lib/LevelLoader.coffee

@@ -116,7 +116,8 @@ module.exports = class LevelLoader extends CocoClass
   # World init
 
   initWorld: ->
-    return if @world
+    return if @initialized
+    @initialized = true
     @world = new World @level.get('name')
     serializedLevel = @level.serialize(@supermodel)
     @world.loadFromLevel serializedLevel, false
@@ -203,9 +204,9 @@ module.exports = class LevelLoader extends CocoClass
   notifyProgress: ->
     Backbone.Mediator.publish 'level-loader:progress-changed', progress: @progress()
     @initWorld() if @allDone()
-#    @trigger 'ready-to-init-world' if @allDone()
     @trigger 'loaded-all' if @progress() is 1
 
   destroy: ->
+    @world = null  # don't hold onto garbage
     @supermodel.off 'loaded-one', @onSupermodelLoadedOne
     super()

app/lib/surface/SpriteBoss.coffee

@@ -19,6 +19,7 @@ module.exports = class SpriteBoss extends CocoClass
     'level-suppress-selection-sounds': 'onSuppressSelectionSounds'
     'level-lock-select': 'onSetLockSelect'
     'level:restarted': 'onLevelRestarted'
+    'god:new-world-created': 'onNewWorld'
 
   constructor: (@options) ->
     super()
@@ -87,7 +88,7 @@ module.exports = class SpriteBoss extends CocoClass
     @selectionMark = new Mark name: 'selection', camera: @camera, layer: @spriteLayers["Ground"], thangType: @thangTypeFor("Selection")
 
   createSpriteOptions: (options) ->
-    _.extend options, camera: @camera, resolutionFactor: 4, groundLayer: @spriteLayers["Ground"], textLayer: @surfaceTextLayer, floatingLayer: @spriteLayers["Floating"], markThangTypes: @markThangTypes(), spriteSheetCache: @spriteSheetCache, showInvisible: @options.showInvisible, world: @world
+    _.extend options, camera: @camera, resolutionFactor: 4, groundLayer: @spriteLayers["Ground"], textLayer: @surfaceTextLayer, floatingLayer: @spriteLayers["Floating"], markThangTypes: @markThangTypes(), spriteSheetCache: @spriteSheetCache, showInvisible: @options.showInvisible
 
   createIndieSprites: (indieSprites, withWizards) ->
     unless @indieSprites
@@ -195,6 +196,9 @@ module.exports = class SpriteBoss extends CocoClass
 
   spriteFor: (thangID) -> @sprites[thangID]
 
+  onNewWorld: (e) ->
+    @world = @options.world = e.world
+
   # Selection
 
   onSuppressSelectionSounds: (e) -> @suppressSelectionSounds = e.suppress

app/lib/world/GoalManager.coffee

@@ -90,6 +90,7 @@ module.exports = class GoalManager extends CocoClass
   # passes the word along
   onNewWorldCreated: (e) =>
     @updateGoalStates(e.goalStates) if e.goalStates?
+    @world = e.world
 
   updateGoalStates: (newGoalStates) ->
     for goalID, goalState of newGoalStates

app/lib/world/world.coffee

@@ -78,7 +78,7 @@ module.exports = class World
     (@runtimeErrors ?= []).push error
     (@unhandledRuntimeErrors ?= []).push error
 
-  loadFrames: (loadedCallback, errorCallback, loadProgressCallback) =>
+  loadFrames: (loadedCallback, errorCallback, loadProgressCallback) ->
     return if @aborted
     unless @thangs.length
       console.log "Warning: loadFrames called on empty World (no thangs)."

app/views/play/level/tome/spell.coffee

@@ -28,7 +28,10 @@ module.exports = class Spell
     @tabView.render()
 
   addThang: (thang) ->
-    @thangs[thang.id] ?= {thang: thang, aether: @createAether(thang), castAether: null}
+    if @thangs[thang.id]
+      @thangs[thang.id].thang = thang
+    else
+      @thangs[thang.id] = {thang: thang, aether: @createAether(thang), castAether: null}
 
   removeThangID: (thangID) ->
     delete @thangs[thangID]

app/views/play/level/tome/thang_list_entry_view.coffee

@@ -134,3 +134,7 @@ module.exports = class ThangListEntryView extends View
     return unless currentThang = e.world.thangMap[@thang.id]
     @$el.toggle Boolean(currentThang.exists)
     @$el.toggleClass 'dead', currentThang.health <= 0 if currentThang.exists
+
+  destroy: ->
+    super()
+    @avatar.destroy()

app/views/play/level/tome/tome_view.coffee

@@ -65,6 +65,7 @@ module.exports = class TomeView extends View
     else
       @cast()
       console.warn "Warning: There are no Programmable Thangs in this level, which makes it unplayable."
+    delete @options.thangs
 
   onNewWorld: (e) ->
     thangs = _.filter e.world.thangs, 'isSelectable'
@@ -95,7 +96,7 @@ module.exports = class TomeView extends View
         @spells[spellKey].addThang thang for spellKey in spellKeys
       else
         delete @thangSpells[thangID]
-        @spells[spellKey].removeThangID thangID for spellKey in spellKeys
+        spell.removeThangID thangID for spell in @spells
     null
 
   onSpellLoaded: (e) ->

app/views/play/level_view.coffee

@@ -50,6 +50,7 @@ module.exports = class PlayLevelView extends View
     'level-focus-dom': 'onFocusDom'
     'level-disable-controls': 'onDisableControls'
     'level-enable-controls': 'onEnableControls'
+    'god:new-world-created': 'onNewWorld'
     'god:infinite-loop': 'onInfiniteLoop'
     'bus:connected': 'onBusConnected'
     'level-reload-from-data': 'onLevelReloadFromData'
@@ -102,7 +103,6 @@ module.exports = class PlayLevelView extends View
 
   load: ->
     @levelLoader = new LevelLoader(@levelID, @supermodel, @sessionID)
-    @levelLoader.once 'ready-to-init-world', @onReadyToInitWorld
     @levelLoader.once 'loaded-all', @onLevelLoaderLoaded
 
   getRenderData: ->
@@ -120,6 +120,8 @@ module.exports = class PlayLevelView extends View
     @session = @levelLoader.session
     @level = @levelLoader.level
     @world = @levelLoader.world
+    @levelLoader.destroy()
+    @levelLoader = null
     @loadingScreen.destroy()
     @setTeam @world.teamForPlayer 1  # We don't know which player we are; this will go away--temp TODO
     @initSurface()
@@ -206,6 +208,9 @@ module.exports = class PlayLevelView extends View
     $('#level-done-button', @$el).hide()
     window.tracker?.trackEvent 'Confirmed Restart', level: @world.name, label: @world.name
 
+  onNewWorld: (e) ->
+    @world = e.world
+
   onInfiniteLoop: (e) ->
     return unless e.firstWorld
     @openModalView new InfiniteLoopModal()
@@ -378,7 +383,7 @@ module.exports = class PlayLevelView extends View
 
   destroy: ->
     super()
-    @levelLoader.destroy()
+    @levelLoader?.destroy()
     @surface?.destroy()
     @god?.destroy()
     @goalManager?.destroy()