Cleanup, redo damage direction

src/Dodge/Zoning/Base.hs

@@ -11,6 +11,7 @@ module Dodge.Zoning.Base
     , zonesAroundPoint
     , xIntercepts
     , yIntercepts'
+    , updateInt2Map
     ) where
 
 import Control.Lens
@@ -78,6 +79,7 @@ yIntercepts' s sp ep = map f $ xIntercepts s (f sp) (f ep)
   where
     f (V2 x y) = V2 y x
 
+-- consider using: at x . non mempty . at y . non mempty <>~ a
 zoneMonoid :: Semigroup m => Int2 -> m -> IM.IntMap (IM.IntMap m) -> IM.IntMap (IM.IntMap m)
 {-# INLINE zoneMonoid #-}
 zoneMonoid (V2 !x !y) a = IM.insertWith f x $! IM.singleton y a
@@ -87,6 +89,10 @@ zoneMonoid (V2 !x !y) a = IM.insertWith f x $! IM.singleton 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
 
+updateInt2Map :: (Eq a,Monoid a) => 
+    (a -> a) -> Int2 -> IM.IntMap (IM.IntMap a) -> IM.IntMap (IM.IntMap a)
+updateInt2Map f (V2 x y) = at x . non mempty . at y . non mempty %~ f
+
 zonesAroundPoint :: Float -> Point2 -> [Int2]
 zonesAroundPoint s p = [V2 a b | a <- [x -1 .. x + 1], b <- [y -1 .. y + 1]]
   where