Creature springs checks for heights

src/Dodge/Update.hs

@@ -975,16 +975,23 @@ canSpring cr =
     cr ^. crPos . _z >= 0 && case cr ^. crHP of
         HP{} -> True
         CrIsCorpse{} -> True
-        CrIsGibs -> False
-        CrIsPitted -> False
+        CrDestroyed{} -> False
 
+-- should possibly limit how big this can get
 crCrSpring :: Creature -> Creature -> World -> World
 crCrSpring c1 c2
     | id1 == id2 = id
     | vec == V2 0 0 = id
     | diff >= comRad = id
+    | diffheight = id
     | otherwise = cWorld . lWorld . creatures %~ ( olap c1 c2 . olap' c2 c1)
   where
+    z c = c ^. crPos . _z
+    h c = fmap (+ z c) (crHeight c)
+    diffheight = fromMaybe True $ do
+        h1 <- h c1
+        h2 <- h c2
+        return $ (z c1 > h2 || z c2 > h1)
     olap a b = ix (a ^. crID) . crPos . _xy +~ overlap b
     olap' a b = ix (a ^. crID) . crPos . _xy -~ overlap b
     id1 = _crID c1