chore(users): grfn -> aspen r/7511

Change-Id: I6c6847fac56f0a9a1a2209792e00a3aec5e672b9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10809
Autosubmit: aspen <root@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: lukegb <lukegb@tvl.fyi>

5 files changed, 846 insertions, 0 deletions

diff --git a/users/aspen/xanthous/src/Xanthous/Generators/Level/CaveAutomata.hs b/users/aspen/xanthous/src/Xanthous/Generators/Level/CaveAutomata.hs
new file mode 100644
index 000000000000..03d534ca39b3
--- /dev/null
+++ b/users/aspen/xanthous/src/Xanthous/Generators/Level/CaveAutomata.hs
@@ -0,0 +1,112 @@
+{-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Level.CaveAutomata
+  ( Params(..)
+  , defaultParams
+  , parseParams
+  , generate
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude
+import           Control.Monad.Random (RandomGen, runRandT)
+import           Data.Array.ST
+import           Data.Array.Unboxed
+import qualified Options.Applicative as Opt
+--------------------------------------------------------------------------------
+import           Xanthous.Util (between)
+import           Xanthous.Util.Optparse
+import           Xanthous.Data (Dimensions, width, height)
+import           Xanthous.Generators.Level.Util
+import           Linear.V2
+--------------------------------------------------------------------------------
+
+data Params = Params
+  { _aliveStartChance :: Double
+  , _birthLimit :: Word
+  , _deathLimit :: Word
+  , _steps :: Word
+  }
+  deriving stock (Show, Eq, Generic)
+makeLenses ''Params
+
+defaultParams :: Params
+defaultParams = Params
+  { _aliveStartChance = 0.6
+  , _birthLimit = 3
+  , _deathLimit = 4
+  , _steps = 4
+  }
+
+parseParams :: Opt.Parser Params
+parseParams = Params
+  <$> Opt.option parseChance
+      ( Opt.long "alive-start-chance"
+      <> Opt.value (defaultParams ^. aliveStartChance)
+      <> Opt.showDefault
+      <> Opt.help ( "Chance for each cell to start alive at the beginning of "
+                 <> "the cellular automata"
+                 )
+      <> Opt.metavar "CHANCE"
+      )
+  <*> Opt.option parseNeighbors
+      ( Opt.long "birth-limit"
+      <> Opt.value (defaultParams ^. birthLimit)
+      <> Opt.showDefault
+      <> Opt.help "Minimum neighbor count required for birth of a cell"
+      <> Opt.metavar "NEIGHBORS"
+      )
+  <*> Opt.option parseNeighbors
+      ( Opt.long "death-limit"
+      <> Opt.value (defaultParams ^. deathLimit)
+      <> Opt.showDefault
+      <> Opt.help "Maximum neighbor count required for death of a cell"
+      <> Opt.metavar "NEIGHBORS"
+      )
+  <*> Opt.option Opt.auto
+      ( Opt.long "steps"
+      <> Opt.value (defaultParams ^. steps)
+      <> Opt.showDefault
+      <> Opt.help "Number of generations to run the automata for"
+      <> Opt.metavar "STEPS"
+      )
+  <**> Opt.helper
+  where
+    parseChance = readWithGuard
+      (between 0 1)
+      $ \res -> "Chance must be in the range [0,1], got: " <> show res
+
+    parseNeighbors = readWithGuard
+      (between 0 8)
+      $ \res -> "Neighbors must be in the range [0,8], got: " <> show res
+
+generate :: RandomGen g => Params -> Dimensions -> g -> Cells
+generate params dims gen
+  = runSTUArray
+  $ fmap fst
+  $ flip runRandT gen
+  $ generate' params dims
+
+generate' :: RandomGen g => Params -> Dimensions -> CellM g s (MCells s)
+generate' params dims = do
+  cells <- randInitialize dims $ params ^. aliveStartChance
+  let steps' = params ^. steps
+  when (steps' > 0)
+   $ for_ [0 .. pred steps'] . const $ stepAutomata cells dims params
+  -- Remove all but the largest contiguous region of unfilled space
+  (_: smallerRegions) <- lift $ regions @UArray . amap not <$> freeze cells
+  lift $ fillAllM (fold smallerRegions) cells
+  lift $ fillOuterEdgesM cells
+  pure cells
+
+stepAutomata :: forall s g. MCells s -> Dimensions -> Params -> CellM g s ()
+stepAutomata cells dims params = do
+  origCells <- lift $ cloneMArray @_ @(STUArray s) cells
+  for_ (range (0, V2 (dims ^. width) (dims ^. height))) $ \pos -> do
+    neighs <- lift $ numAliveNeighborsM origCells pos
+    origValue <- lift $ readArray origCells pos
+    lift . writeArray cells pos
+      $ if origValue
+        then neighs >= params ^. deathLimit
+        else neighs > params ^. birthLimit
diff --git a/users/aspen/xanthous/src/Xanthous/Generators/Level/Dungeon.hs b/users/aspen/xanthous/src/Xanthous/Generators/Level/Dungeon.hs
new file mode 100644
index 000000000000..0be7c0435c5a
--- /dev/null
+++ b/users/aspen/xanthous/src/Xanthous/Generators/Level/Dungeon.hs
@@ -0,0 +1,190 @@
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Level.Dungeon
+  ( Params(..)
+  , defaultParams
+  , parseParams
+  , generate
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding ((:>))
+--------------------------------------------------------------------------------
+import           Control.Monad.Random
+import           Data.Array.ST
+import           Data.Array.IArray (amap)
+import           Data.Stream.Infinite (Stream(..))
+import qualified Data.Stream.Infinite as Stream
+import qualified Data.Graph.Inductive.Graph as Graph
+import           Data.Graph.Inductive.PatriciaTree
+import qualified Data.List.NonEmpty as NE
+import           Data.Maybe (fromJust)
+import           Linear.V2
+import           Linear.Metric
+import qualified Options.Applicative as Opt
+--------------------------------------------------------------------------------
+import           Xanthous.Random
+import           Xanthous.Data hiding (x, y, _x, _y, edges, distance)
+import           Xanthous.Generators.Level.Util
+import           Xanthous.Util.Graphics (delaunay, straightLine)
+import           Xanthous.Util.Graph (mstSubGraph)
+--------------------------------------------------------------------------------
+
+data Params = Params
+  { _numRoomsRange :: (Word, Word)
+  , _roomDimensionRange :: (Word, Word)
+  , _connectednessRatioRange :: (Double, Double)
+  }
+  deriving stock (Show, Eq, Ord, Generic)
+makeLenses ''Params
+
+defaultParams :: Params
+defaultParams = Params
+  { _numRoomsRange = (6, 8)
+  , _roomDimensionRange = (3, 12)
+  , _connectednessRatioRange = (0.1, 0.15)
+  }
+
+parseParams :: Opt.Parser Params
+parseParams = Params
+  <$> parseRange
+        "num-rooms"
+        "number of rooms to generate in the dungeon"
+        "ROOMS"
+        (defaultParams ^. numRoomsRange)
+  <*> parseRange
+        "room-size"
+        "size in tiles of one of the sides of a room"
+        "TILES"
+        (defaultParams ^. roomDimensionRange)
+  <*> parseRange
+        "connectedness-ratio"
+        ( "ratio of edges from the delaunay triangulation to re-add to the "
+        <> "minimum-spanning-tree")
+        "RATIO"
+        (defaultParams ^. connectednessRatioRange)
+  <**> Opt.helper
+  where
+    parseRange name desc metavar (defMin, defMax) =
+      (,)
+      <$> Opt.option Opt.auto
+          ( Opt.long ("min-" <> name)
+          <> Opt.value defMin
+          <> Opt.showDefault
+          <> Opt.help ("Minimum " <> desc)
+          <> Opt.metavar metavar
+          )
+      <*> Opt.option Opt.auto
+          ( Opt.long ("max-" <> name)
+          <> Opt.value defMax
+          <> Opt.showDefault
+          <> Opt.help ("Maximum " <> desc)
+          <> Opt.metavar metavar
+          )
+
+generate :: RandomGen g => Params -> Dimensions -> g -> Cells
+generate params dims gen
+  = amap not
+  $ runSTUArray
+  $ fmap fst
+  $ flip runRandT gen
+  $ generate' params dims
+
+--------------------------------------------------------------------------------
+
+generate' :: RandomGen g => Params -> Dimensions -> CellM g s (MCells s)
+generate' params dims = do
+  cells <- initializeEmpty dims
+  rooms <- genRooms params dims
+  for_ rooms $ fillRoom cells
+
+  let fullRoomGraph = delaunayRoomGraph rooms
+      mst = mstSubGraph fullRoomGraph
+      mstEdges = Graph.edges mst
+      nonMSTEdges = filter (\(n₁, n₂, _) -> (n₁, n₂) `notElem` mstEdges)
+                    $ Graph.labEdges fullRoomGraph
+
+  reintroEdgeCount <- floor . (* fromIntegral (length nonMSTEdges))
+                     <$> getRandomR (params ^. connectednessRatioRange)
+  let reintroEdges = take reintroEdgeCount nonMSTEdges
+      corridorGraph = Graph.insEdges reintroEdges mst
+
+  corridors <- traverse
+              ( uncurry corridorBetween
+              . over both (fromJust . Graph.lab corridorGraph)
+              ) $ Graph.edges corridorGraph
+
+  for_ (join corridors) $ \pt -> lift $ writeArray cells pt True
+
+  pure cells
+
+type Room = Box Word
+
+genRooms :: MonadRandom m => Params -> Dimensions -> m [Room]
+genRooms params dims = do
+  numRooms <- fromIntegral <$> getRandomR (params ^. numRoomsRange)
+  subRand . fmap (Stream.take numRooms . removeIntersecting []) . infinitely $ do
+    roomWidth <- getRandomR $ params ^. roomDimensionRange
+    roomHeight <- getRandomR $ params ^. roomDimensionRange
+    xPos <- getRandomR (0, dims ^. width - roomWidth)
+    yPos <- getRandomR (0, dims ^. height - roomHeight)
+    pure Box
+      { _topLeftCorner = V2 xPos yPos
+      , _dimensions = V2 roomWidth roomHeight
+      }
+  where
+    removeIntersecting seen (room :> rooms)
+      | any (boxIntersects room) seen
+      = removeIntersecting seen rooms
+      | otherwise
+      = room :> removeIntersecting (room : seen) rooms
+    streamRepeat x = x :> streamRepeat x
+    infinitely = sequence . streamRepeat
+
+delaunayRoomGraph :: [Room] -> Gr Room Double
+delaunayRoomGraph rooms =
+  Graph.insEdges edges . Graph.insNodes nodes $ Graph.empty
+  where
+    edges = map (\((n₁, room₁), (n₂, room₂)) -> (n₁, n₂, roomDist room₁ room₂))
+          . over (mapped . both) snd
+          . delaunay @Double
+          . NE.fromList
+          . map (\p@(_, room) -> (boxCenter $ fromIntegral <$> room, p))
+          $ nodes
+    nodes = zip [0..] rooms
+    roomDist = distance `on` (boxCenter . fmap fromIntegral)
+
+fillRoom :: MCells s -> Room -> CellM g s ()
+fillRoom cells room =
+  let V2 posx posy = room ^. topLeftCorner
+      V2 dimx dimy = room ^. dimensions
+  in for_ [posx .. posx + dimx] $ \x ->
+       for_ [posy .. posy + dimy] $ \y ->
+         lift $ writeArray cells (V2 x y) True
+
+corridorBetween :: MonadRandom m => Room -> Room -> m [V2 Word]
+corridorBetween originRoom destinationRoom
+  = straightLine <$> origin <*> destination
+  where
+    origin = choose . NE.fromList =<< originEdge
+    destination = choose . NE.fromList =<< destinationEdge
+    originEdge = pickEdge originRoom originCorner
+    destinationEdge = pickEdge destinationRoom destinationCorner
+    pickEdge room corner = choose . over both (boxEdge room) $ cornerEdges corner
+    originCorner =
+      case ( compare (originRoom ^. topLeftCorner . _x)
+                     (destinationRoom ^. topLeftCorner . _x)
+           , compare (originRoom ^. topLeftCorner . _y)
+                     (destinationRoom ^. topLeftCorner . _y)
+           ) of
+        (LT, LT) -> BottomRight
+        (LT, GT) -> TopRight
+        (GT, LT) -> BottomLeft
+        (GT, GT) -> TopLeft
+
+        (EQ, LT) -> BottomLeft
+        (EQ, GT) -> TopRight
+        (GT, EQ) -> TopLeft
+        (LT, EQ) -> BottomRight
+        (EQ, EQ) -> TopLeft -- should never happen
+
+    destinationCorner = opposite originCorner
diff --git a/users/aspen/xanthous/src/Xanthous/Generators/Level/LevelContents.hs b/users/aspen/xanthous/src/Xanthous/Generators/Level/LevelContents.hs
new file mode 100644
index 000000000000..4f8a2f42ee16
--- /dev/null
+++ b/users/aspen/xanthous/src/Xanthous/Generators/Level/LevelContents.hs
@@ -0,0 +1,182 @@
+{-# LANGUAGE RecordWildCards #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Level.LevelContents
+  ( chooseCharacterPosition
+  , randomItems
+  , randomCreatures
+  , randomDoors
+  , placeDownStaircase
+  , tutorialMessage
+  , entityFromRaw
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding (any, toList)
+--------------------------------------------------------------------------------
+import           Control.Monad.Random
+import           Data.Array.IArray (amap, bounds, rangeSize, (!))
+import qualified Data.Array.IArray as Arr
+import           Data.Foldable (any, toList)
+import           Linear.V2
+--------------------------------------------------------------------------------
+import           Xanthous.Generators.Level.Util
+import           Xanthous.Random hiding (chance)
+import qualified Xanthous.Random as Random
+import           Xanthous.Data
+                 ( positionFromV2,  Position, _Position
+                 , rotations, arrayNeighbors, Neighbors(..)
+                 , neighborPositions
+                 )
+import           Xanthous.Data.EntityMap (EntityMap, _EntityMap)
+import           Xanthous.Entities.Raws (rawsWithType, RawType, raw)
+import qualified Xanthous.Entities.Item as Item
+import           Xanthous.Entities.Item (Item)
+import qualified Xanthous.Entities.Creature as Creature
+import           Xanthous.Entities.Creature (Creature)
+import           Xanthous.Entities.Environment
+                 (GroundMessage(..), Door(..), unlockedDoor, Staircase(..))
+import           Xanthous.Messages (message_)
+import           Xanthous.Util.Graphics (circle)
+import           Xanthous.Entities.RawTypes
+import           Xanthous.Entities.Creature.Hippocampus (initialHippocampus)
+import           Xanthous.Entities.Common (inRightHand, asWieldedItem, wielded)
+import           Xanthous.Game.State (SomeEntity(SomeEntity))
+--------------------------------------------------------------------------------
+
+chooseCharacterPosition :: MonadRandom m => Cells -> m Position
+chooseCharacterPosition = randomPosition
+
+randomItems :: MonadRandom m => Cells -> m (EntityMap Item)
+randomItems = randomEntities (fmap Identity . Item.newWithType) (0.0004, 0.001)
+
+placeDownStaircase :: MonadRandom m => Cells -> m (EntityMap Staircase)
+placeDownStaircase cells = do
+  pos <- randomPosition cells
+  pure $ _EntityMap # [(pos, DownStaircase)]
+
+randomDoors :: MonadRandom m => Cells -> m (EntityMap Door)
+randomDoors cells = do
+  doorRatio <- getRandomR subsetRange
+  let numDoors = floor $ doorRatio * fromIntegral (length candidateCells)
+      doorPositions =
+        removeAdjacent . fmap positionFromV2 . take numDoors $ candidateCells
+      doors = zip doorPositions $ repeat unlockedDoor
+  pure $ _EntityMap # doors
+  where
+    removeAdjacent =
+      foldr (\pos acc ->
+               if pos `elem` (acc >>= toList . neighborPositions)
+               then acc
+               else pos : acc
+            ) []
+    candidateCells = filter doorable $ Arr.indices cells
+    subsetRange = (0.8 :: Double, 1.0)
+    doorable pos =
+      not (fromMaybe True $ cells ^? ix pos)
+      && any (teeish . fmap (fromMaybe True))
+        (rotations $ arrayNeighbors cells pos)
+    -- only generate doors at the *ends* of hallways, eg (where O is walkable,
+    -- X is a wall, and D is a door):
+    --
+    -- O O O
+    -- X D X
+    --   O
+    teeish (fmap not -> (Neighbors tl t tr l r _ b _ )) =
+      and [tl, t, tr, b] && (and . fmap not) [l, r]
+
+randomCreatures
+  :: MonadRandom m
+  => Word -- ^ Level number, starting at 0
+  -> Cells
+  -> m (EntityMap Creature)
+randomCreatures levelNumber
+  = randomEntities maybeNewCreature (0.0007, 0.002)
+  where
+    maybeNewCreature cType
+      | maybe True (canGenerate levelNumber) $ cType ^. generateParams
+      = Just <$> newCreatureWithType cType
+      | otherwise
+      = pure Nothing
+
+newCreatureWithType :: MonadRandom m => CreatureType -> m Creature
+newCreatureWithType _creatureType = do
+  let _hitpoints = _creatureType ^. maxHitpoints
+      _hippocampus = initialHippocampus
+
+  equipped <- fmap join
+            . traverse genEquipped
+            $ _creatureType
+            ^.. generateParams . _Just . equippedItem . _Just
+  let _inventory = maybe id (\ei -> wielded .~ inRightHand ei) (headMay equipped) mempty
+  pure Creature.Creature {..}
+  where
+    genEquipped cei = do
+      doGen <- Random.chance $ cei ^. chance
+      let entName = cei ^. entityName
+          itemType =
+            fromMaybe (error $ "raw \"" <> unpack entName <> "\" not of type Item")
+            . preview _Item
+            . fromMaybe (error $ "Could not find raw: " <> unpack entName)
+            $ raw entName
+      item <- Item.newWithType itemType
+      if doGen
+        then pure [fromMaybe (error $ "raw \"" <> unpack entName <> "\" not wieldable")
+                  $ preview asWieldedItem item]
+        else pure []
+
+
+tutorialMessage :: MonadRandom m
+  => Cells
+  -> Position -- ^ CharacterPosition
+  -> m (EntityMap GroundMessage)
+tutorialMessage cells characterPosition = do
+  let distance = 2
+  pos <- fmap (fromMaybe (error "No valid positions for tutorial message?"))
+        . choose . ChooseElement
+        $ accessiblePositionsWithin distance cells characterPosition
+  msg <- message_ ["tutorial", "message1"]
+  pure $ _EntityMap # [(pos, GroundMessage msg)]
+  where
+    accessiblePositionsWithin :: Int -> Cells -> Position -> [Position]
+    accessiblePositionsWithin dist valid pos =
+      review _Position
+      <$> filter
+            (\pt -> not $ valid ! (fromIntegral <$> pt))
+            (circle (pos ^. _Position) dist)
+
+randomEntities
+  :: forall entity raw m t. (MonadRandom m, RawType raw, Functor t, Foldable t)
+  => (raw -> m (t entity))
+  -> (Float, Float)
+  -> Cells
+  -> m (EntityMap entity)
+randomEntities newWithType sizeRange cells =
+  case fromNullable $ rawsWithType @raw of
+    Nothing -> pure mempty
+    Just raws -> do
+      let len = rangeSize $ bounds cells
+      (numEntities :: Int) <-
+        floor . (* fromIntegral len) <$> getRandomR sizeRange
+      entities <- for [0..numEntities] $ const $ do
+        pos <- randomPosition cells
+        r <- choose raws
+        entities <- newWithType r
+        pure $ (pos, ) <$> entities
+      pure $ _EntityMap # (entities >>= toList)
+
+randomPosition :: MonadRandom m => Cells -> m Position
+randomPosition = fmap positionFromV2 . choose . impureNonNull . cellCandidates
+
+-- cellCandidates :: Cells -> Cells
+cellCandidates :: Cells -> Set (V2 Word)
+cellCandidates
+  -- find the largest contiguous region of cells in the cave.
+  = maximumBy (compare `on` length)
+  . fromMaybe (error "No regions generated! this should never happen.")
+  . fromNullable
+  . regions
+  -- cells ends up with true = wall, we want true = can put an item here
+  . amap not
+
+entityFromRaw :: MonadRandom m => EntityRaw -> m SomeEntity
+entityFromRaw (Creature ct) = SomeEntity <$> newCreatureWithType ct
+entityFromRaw (Item it) = SomeEntity <$> Item.newWithType it
diff --git a/users/aspen/xanthous/src/Xanthous/Generators/Level/Util.hs b/users/aspen/xanthous/src/Xanthous/Generators/Level/Util.hs
new file mode 100644
index 000000000000..0008eb965c42
--- /dev/null
+++ b/users/aspen/xanthous/src/Xanthous/Generators/Level/Util.hs
@@ -0,0 +1,236 @@
+{-# LANGUAGE QuantifiedConstraints #-}
+{-# LANGUAGE AllowAmbiguousTypes #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Level.Util
+  ( MCells
+  , Cells
+  , CellM
+  , randInitialize
+  , initializeEmpty
+  , numAliveNeighborsM
+  , numAliveNeighbors
+  , fillOuterEdgesM
+  , cloneMArray
+  , floodFill
+  , regions
+  , fillAll
+  , fillAllM
+  , fromPoints
+  , fromPointsM
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding (Foldable, toList, for_)
+--------------------------------------------------------------------------------
+import           Data.Array.ST
+import           Data.Array.Unboxed
+import           Control.Monad.ST
+import           Control.Monad.Random
+import           Data.Monoid
+import           Data.Foldable (Foldable, toList, for_)
+import qualified Data.Set as Set
+import           Data.Semigroup.Foldable
+import           Linear.V2
+--------------------------------------------------------------------------------
+import           Xanthous.Util (foldlMapM', maximum1, minimum1)
+import           Xanthous.Data (Dimensions, width, height)
+--------------------------------------------------------------------------------
+
+type MCells s = STUArray s (V2 Word) Bool
+type Cells = UArray (V2 Word) Bool
+type CellM g s a = RandT g (ST s) a
+
+randInitialize :: RandomGen g => Dimensions -> Double -> CellM g s (MCells s)
+randInitialize dims aliveChance = do
+  res <- initializeEmpty dims
+  for_ [0..dims ^. width] $ \i ->
+    for_ [0..dims ^. height] $ \j -> do
+      val <- (>= aliveChance) <$> getRandomR (0, 1)
+      lift $ writeArray res (V2 i j) val
+  pure res
+
+initializeEmpty :: RandomGen g => Dimensions -> CellM g s (MCells s)
+initializeEmpty dims =
+  lift $ newArray (0, V2 (dims ^. width) (dims ^. height)) False
+
+-- | Returns the number of neighbors of the given point in the given array that
+-- are True.
+--
+-- Behavior if point is out-of-bounds for the array is undefined, but will not
+-- error
+numAliveNeighborsM
+  :: forall a i m
+  . (MArray a Bool m, Ix i, Integral i)
+  => a (V2 i) Bool
+  -> V2 i
+  -> m Word
+numAliveNeighborsM cells pt@(V2 x y) = do
+  cellBounds <- getBounds cells
+  getSum <$> foldlMapM'
+    (fmap (Sum . fromIntegral . fromEnum) . boundedGet cellBounds)
+    neighborPositions
+
+  where
+    boundedGet :: (V2 i, V2 i) -> (Int, Int) -> m Bool
+    boundedGet bnds _
+      | not (inRange bnds pt)
+      = pure True
+    boundedGet (V2 minX minY, V2 maxX maxY) (i, j)
+      | (x <= minX && i < 0)
+      || (y <= minY && j < 0)
+      || (x >= maxX && i > 0)
+      || (y >= maxY && j > 0)
+      = pure True
+      | otherwise =
+        let nx = fromIntegral $ fromIntegral x + i
+            ny = fromIntegral $ fromIntegral y + j
+        in readArray cells $ V2 nx ny
+
+-- | Returns the number of neighbors of the given point in the given array that
+-- are True.
+--
+-- Behavior if point is out-of-bounds for the array is undefined, but will not
+-- error
+numAliveNeighbors
+  :: forall a i
+  . (IArray a Bool, Ix i, Integral i)
+  => a (V2 i) Bool
+  -> V2 i
+  -> Word
+numAliveNeighbors cells pt@(V2 x y) =
+  let cellBounds = bounds cells
+  in getSum $ foldMap
+      (Sum . fromIntegral . fromEnum . boundedGet cellBounds)
+      neighborPositions
+
+  where
+    boundedGet :: (V2 i, V2 i) -> (Int, Int) -> Bool
+    boundedGet bnds _
+      | not (inRange bnds pt)
+      = True
+    boundedGet (V2 minX minY, V2 maxX maxY) (i, j)
+      | (x <= minX && i < 0)
+      || (y <= minY && j < 0)
+      || (x >= maxX && i > 0)
+      || (y >= maxY && j > 0)
+      = True
+      | otherwise =
+        let nx = fromIntegral $ fromIntegral x + i
+            ny = fromIntegral $ fromIntegral y + j
+        in cells ! V2 nx ny
+
+neighborPositions :: [(Int, Int)]
+neighborPositions = [(i, j) | i <- [-1..1], j <- [-1..1], (i, j) /= (0, 0)]
+
+fillOuterEdgesM :: (MArray a Bool m, Ix i) => a (V2 i) Bool -> m ()
+fillOuterEdgesM arr = do
+  (V2 minX minY, V2 maxX maxY) <- getBounds arr
+  for_ (range (minX, maxX)) $ \x -> do
+    writeArray arr (V2 x minY) True
+    writeArray arr (V2 x maxY) True
+  for_ (range (minY, maxY)) $ \y -> do
+    writeArray arr (V2 minX y) True
+    writeArray arr (V2 maxX y) True
+
+cloneMArray
+  :: forall a a' i e m.
+  ( Ix i
+  , MArray a e m
+  , MArray a' e m
+  , IArray UArray e
+  )
+  => a i e
+  -> m (a' i e)
+cloneMArray = thaw @_ @UArray <=< freeze
+
+--------------------------------------------------------------------------------
+
+-- | Flood fill a cell array starting at a point, returning a list of all the
+-- (true) cell locations reachable from that point
+floodFill :: forall a i.
+            ( IArray a Bool
+            , Ix i
+            , Enum i
+            , Bounded i
+            , Eq i
+            )
+          => a (V2 i) Bool -- ^ array
+          -> (V2 i)        -- ^ position
+          -> Set (V2 i)
+floodFill = go mempty
+  where
+    go :: Set (V2 i) -> a (V2 i) Bool -> (V2 i) -> Set (V2 i)
+    go res arr@(bounds -> arrBounds) idx@(V2 x y)
+      | not (inRange arrBounds idx) =  res
+      | not (arr ! idx) =  res
+      | otherwise =
+        let neighbors
+              = filter (inRange arrBounds)
+              . filter (/= idx)
+              . filter (`notMember` res)
+              $ V2
+              <$> [(if x == minBound then x else pred x)
+                   ..
+                   (if x == maxBound then x else succ x)]
+              <*> [(if y == minBound then y else pred y)
+                   ..
+                   (if y == maxBound then y else succ y)]
+        in foldl' (\r idx' ->
+                     if arr ! idx'
+                     then r <> (let r' = r & contains idx' .~ True
+                               in r' `seq` go r' arr idx')
+                     else r)
+           (res & contains idx .~ True) neighbors
+{-# SPECIALIZE floodFill :: UArray (V2 Word) Bool -> (V2 Word) -> Set (V2 Word) #-}
+
+-- | Gives a list of all the disconnected regions in a cell array, represented
+-- each as lists of points
+regions :: forall a i.
+          ( IArray a Bool
+          , Ix i
+          , Enum i
+          , Bounded i
+          , Eq i
+          )
+        => a (V2 i) Bool
+        -> [Set (V2 i)]
+regions arr
+  | Just firstPoint <- findFirstPoint arr =
+      let region = floodFill arr firstPoint
+          arr' = fillAll region arr
+      in region : regions arr'
+  | otherwise = []
+  where
+    findFirstPoint :: a (V2 i) Bool -> Maybe (V2 i)
+    findFirstPoint = fmap fst . headMay . filter snd . assocs
+{-# SPECIALIZE regions :: UArray (V2 Word) Bool -> [Set (V2 Word)] #-}
+
+fillAll :: (IArray a Bool, Ix i, Foldable f) => f i -> a i Bool -> a i Bool
+fillAll ixes a = accum (const fst) a $ (, (False, ())) <$> toList ixes
+
+fillAllM :: (MArray a Bool m, Ix i, Foldable f) => f i -> a i Bool -> m ()
+fillAllM ixes a = for_ ixes $ \i -> writeArray a i False
+
+fromPoints
+  :: forall a f i.
+    ( IArray a Bool
+    , Ix i
+    , Functor f
+    , Foldable1 f
+    )
+  => f (i, i)
+  -> a (i, i) Bool
+fromPoints points =
+  let pts = Set.fromList $ toList points
+      dims = ( (minimum1 $ fst <$> points, minimum1 $ snd <$> points)
+             , (maximum1 $ fst <$> points, maximum1 $ snd <$> points)
+             )
+  in array dims $ range dims <&> \i -> (i, i `member` pts)
+
+fromPointsM
+  :: (MArray a Bool m, Ix i, Element f ~ i, MonoFoldable f)
+  => NonNull f
+  -> m (a i Bool)
+fromPointsM points = do
+  arr <- newArray (minimum points, maximum points) False
+  fillAllM (otoList points) arr
+  pure arr
diff --git a/users/aspen/xanthous/src/Xanthous/Generators/Level/Village.hs b/users/aspen/xanthous/src/Xanthous/Generators/Level/Village.hs
new file mode 100644
index 000000000000..ab7de95e6806
--- /dev/null
+++ b/users/aspen/xanthous/src/Xanthous/Generators/Level/Village.hs
@@ -0,0 +1,126 @@
+--------------------------------------------------------------------------------
+module Xanthous.Generators.Level.Village
+  ( fromCave
+  ) where
+--------------------------------------------------------------------------------
+import           Xanthous.Prelude hiding (any, failing, toList)
+--------------------------------------------------------------------------------
+import           Control.Monad.Random (MonadRandom)
+import           Control.Monad.State (execStateT, MonadState, modify)
+import           Control.Monad.Trans.Maybe
+import           Control.Parallel.Strategies
+import           Data.Array.IArray
+import           Data.Foldable (any, toList)
+--------------------------------------------------------------------------------
+import           Xanthous.Data
+import           Xanthous.Data.EntityMap (EntityMap)
+import qualified Xanthous.Data.EntityMap as EntityMap
+import           Xanthous.Entities.Environment
+import           Xanthous.Generators.Level.Util
+import           Xanthous.Game.State (SomeEntity(..))
+import           Xanthous.Random
+--------------------------------------------------------------------------------
+
+fromCave :: MonadRandom m
+         => Cells -- ^ The positions of all the walls
+         -> m (EntityMap SomeEntity)
+fromCave wallPositions = execStateT (fromCave' wallPositions) mempty
+
+fromCave' :: forall m. (MonadRandom m, MonadState (EntityMap SomeEntity) m)
+          => Cells
+          -> m ()
+fromCave' wallPositions = failing (pure ()) $ do
+  Just villageRegion <-
+    choose
+    . (`using` parTraversable rdeepseq)
+    . weightedBy (\reg -> let circSize = length $ circumference reg
+                         in if circSize == 50
+                            then (1.0 :: Double)
+                            else 1.0 / (fromIntegral . abs $ circSize - 50))
+    $ regions closedHallways
+
+  let circ = setFromList . circumference $ villageRegion
+
+  centerPoints <- chooseSubset (0.1 :: Double) $ toList circ
+
+  roomTiles <- foldM
+              (flip $ const $ stepOut circ)
+              (map pure centerPoints)
+              [0 :: Int ..2]
+
+  let roomWalls = circumference . setFromList @(Set _) <$> roomTiles
+      allWalls = join roomWalls
+
+  doorPositions <- fmap join . for roomWalls $ \room ->
+    let candidates = filter (`notMember` circ) room
+    in fmap toList . choose $ ChooseElement candidates
+
+  let entryways =
+        filter (\pt ->
+                  let ncs = neighborCells pt
+                  in any ((&&) <$> (not . (wallPositions !))
+                              <*> (`notMember` villageRegion)) ncs
+                   && any ((&&) <$> (`member` villageRegion)
+                              <*> (`notElem` allWalls)) ncs)
+                  $ toList villageRegion
+
+  Just entryway <- choose $ ChooseElement entryways
+
+  for_ (filter ((&&) <$> (`notElem` doorPositions) <*> (/= entryway)) allWalls)
+    $ insertEntity Wall
+  for_ (filter (/= entryway) doorPositions) $ insertEntity unlockedDoor
+  insertEntity unlockedDoor entryway
+
+
+  where
+    insertEntity e pt = modify $ EntityMap.insertAt (ptToPos pt) $ SomeEntity e
+    ptToPos pt = _Position # (fromIntegral <$> pt)
+
+    stepOut :: Set (V2 Word) -> [[V2 Word]] -> MaybeT m [[V2 Word]]
+    stepOut circ rooms = for rooms $ \room ->
+      let nextLevels = hashNub $ toList . neighborCells =<< room
+      in pure
+         . (<> room)
+         $ filter ((&&) <$> (`notMember` circ) <*> (`notElem` join rooms))
+         nextLevels
+
+    circumference pts =
+      filter (any (`notMember` pts) . neighborCells) $ toList pts
+    closedHallways = closeHallways livePositions
+    livePositions = amap not wallPositions
+
+--------------------------------------------------------------------------------
+
+closeHallways :: Cells -> Cells
+closeHallways livePositions =
+  livePositions // mapMaybe closeHallway (assocs livePositions)
+  where
+    closeHallway (_, False) = Nothing
+    closeHallway (pos, _)
+      | isHallway pos = Just (pos, False)
+      | otherwise     = Nothing
+    isHallway pos = any ((&&) <$> not . view left <*> not . view right)
+      . rotations
+      . fmap (fromMaybe False)
+      $ arrayNeighbors livePositions pos
+
+failing :: Monad m => m a -> MaybeT m a -> m a
+failing result = (maybe result pure =<<) . runMaybeT
+
+{-
+
+import Xanthous.Generators.Village
+import Xanthous.Generators
+import Xanthous.Data
+import System.Random
+import qualified Data.Text
+import qualified Xanthous.Generators.CaveAutomata as CA
+let gi = GeneratorInput SCaveAutomata CA.defaultParams
+wallPositions <- generateFromInput gi (Dimensions 80 50) <$> getStdGen
+putStrLn . Data.Text.unpack $ showCells wallPositions
+
+import Data.Array.IArray
+let closedHallways = closeHallways . amap not $ wallPositions
+putStrLn . Data.Text.unpack . showCells $ amap not closedHallways
+
+-}