Control wall damage effects using the wall

src/Dodge/Update.hs

@@ -89,11 +89,10 @@ splinterBlock bl w = foldr unshadowBlock w (_blShadows bl) -- foldr shiftTowardC
     & blocks . ix (_blID bl) . blHPs %~ tail
     & theSoundEffect cen
   where
-    wls = map (_walls w IM.!) (IS.toList $ _blWallIDs bl)
-    ps = map (fst . _wlLine) wls
-    cen = centroid ps
+    wls = IM.restrictKeys (_walls w) (_blWallIDs bl)
+    cen = centroid $ fmap (fst . _wlLine) wls
     theSoundEffect 
-        | _wlOpacity (head wls) == SeeThrough = mkSoundSplinterGlass
+        | _wlOpacity (snd $ IM.findMin wls) == SeeThrough = mkSoundSplinterGlass
         | otherwise                           = mkSoundSplinterBlock
 
 unshadowBlock :: Int -> World -> World
@@ -121,7 +120,6 @@ destroyBlock bl w = w
   where
     wlids = _blWallIDs bl
     pos = fst . _wlLine $ _walls w IM.! IS.findMin wlids
-
 -- | Note the explict use of record syntax. Using lens created a space leak.
 resetWorldEvents :: World -> World
 resetWorldEvents w = w {_worldEvents = id}