refactor(users/glittershark): Rename to grfn r/2485

Rename my //users directory and all places that refer to glittershark to
grfn, including nix references and documentation.

This may require some extra attention inside of gerrit's database after
it lands to allow me to actually push things.

Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>

1 files changed, 112 insertions, 0 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/Generators/CaveAutomata.hs b/users/grfn/xanthous/src/Xanthous/Generators/CaveAutomata.hs
new file mode 100644
index 000000000000..be904662f3f7
--- /dev/null
+++ b/users/grfn/xanthous/src/Xanthous/Generators/CaveAutomata.hs
@@ -0,0 +1,112 @@
+{-# LANGUAGE MultiWayIf #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TemplateHaskell #-}
+--------------------------------------------------------------------------------
+module Xanthous.Generators.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.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