Start simplifying/removing Wall records

src/Dodge/WorldEvent/ThingsHit.hs

@@ -14,8 +14,11 @@ module Dodge.WorldEvent.ThingsHit (
     crHit,
     crWlPbHit,
     wlsHitUnsorted,
+    isWalkable,
 ) where
 
+import Data.Monoid
+import qualified Data.Set as S
 import Linear
 import Dodge.Data.Object
 import Dodge.Creature.Radius
@@ -155,3 +158,16 @@ crsHitRadial p r = mapMaybe f . crsNearCirc p r
         let cp = cr ^. crPos . _xy
         guard $ dist p cp < r + crRad (_crType cr)
         return (cp + (1 + crRad (_crType cr)) *.* (cp - p), cr)
+
+isFlyable :: Point2 -> Point2 -> World -> Bool
+{-# INLINE isFlyable #-}
+isFlyable p1 p2 =
+    not . (WallNotAutoOpen `S.member`) 
+        . foldMap (^. _2 . wlPathFlag)
+        . wlsHitUnsorted p1 p2
+
+isWalkable :: Point2 -> Point2 -> World -> Bool
+{-# INLINE isWalkable #-}
+isWalkable p1 p2 w = isFlyable p1 p2 w && not (getAny $ foldMap f (w ^. cWorld . chasms))
+  where
+    f = foldMap (Any . isJust . uncurry (intersectSegSeg p1 p2)) . loopPairs