Fix aiming with no weapon crash

src/Dodge/WorldEvent/ThingsHit.hs

@@ -4,6 +4,7 @@ Find which objects lie upon a line.
  -}
 module Dodge.WorldEvent.ThingsHit
     ( thingsHit
+    , wallsHit
     , thingHit
     , thingsHitLongLine
     , thingsHitExceptCr
@@ -59,6 +60,26 @@ thingsHitExceptCr (Just cid) sp ep = filter crNotCid . thingsHit sp ep
     crNotCid (_,Left cr) = _crID cr /= cid
     crNotCid _ = True
 
+wallsHit
+    :: Point2    -- ^ Line start point
+    -> Point2    -- ^ Line end point
+    -> World 
+    -> [(Point2, Wall)]
+wallsHit sp ep w 
+    | sp == ep  = []
+    | otherwise = sortOn (dist sp . fst) wls
+  where 
+    hitWls   = wallsOnLine sp ep 
+        $ IM.unions [f b $ f a $ _znObjects $ _wallsZone w 
+            | a<-[x-1,x,x+1] , b<-[y-1,y,y+1]]
+       -- $ _walls w
+    (x,y) = zoneOfPoint (0.5 *.* (sp +.+ ep))
+    f i m = case IM.lookup i m of 
+        Just val -> val
+        _        -> IM.empty
+    wls = zip (map (fromJust . hitPoint) hitWls) hitWls
+    hitPoint w' = uncurry (intersectSegSeg sp ep) (_wlLine w')
+
 thingsHitExceptCrLongLine 
     :: Maybe Int 
     -> Point2