Refactor cloud zoning

src/Dodge/Zoning/Base.hs

@@ -3,6 +3,7 @@ import Geometry
 import Geometry.Zone
 import qualified IntMapHelp as IM
 
+import qualified Data.IntSet as IS
 import Control.Lens
 import Data.Maybe
 
@@ -60,3 +61,10 @@ zoneMonoid :: Semigroup m => Int2 -> m -> IM.IntMap (IM.IntMap m) -> IM.IntMap (
 zoneMonoid (V2 x y) a = IM.insertWith f x $ IM.singleton y a
   where
     f _ = IM.insertWith (<>) y a
+
+deZoneIX :: Int -> IM.IntMap (IM.IntMap IS.IntSet) -> Int2 ->  IM.IntMap (IM.IntMap IS.IntSet)
+deZoneIX i im (V2 x y) = im & ix x . ix y %~ IS.delete i
+
+zoneOfPoint'' :: Float -> Point2 -> V2 Int
+{-# INLINE zoneOfPoint'' #-}
+zoneOfPoint'' s = fmap (divTo s)