Allow more general detection of item use focus

src/Dodge/Creature/Impulse/UseItem.hs

@@ -24,7 +24,7 @@ useSelectedItem crid w = (worldEventFlags . at InventoryChange ?~ ()) . fromMayb
     invid <- cr ^? crManipulation . manObject . imSelectedItem
     itmtree <- invRootTrees (_crInv cr) ^? ix itRef
     itmloc <- allInvLocs (_crInv cr) ^? ix invid . _2
-    let usedloc = case itmloc ^. locLDT . ldtValue . _1 . itUseFocus of
+    let usedloc = case useLocation itmloc of
             UseFromLocation -> itmloc ^. locLDT
             UseFromRoot -> locToTop itmloc ^. locLDT
     let itm = usedloc ^. ldtValue . _1
@@ -46,6 +46,13 @@ useSelectedItem crid w = (worldEventFlags . at InventoryChange ?~ ()) . fromMayb
   where
     fst3 (x,_,_) = x
 
+useLocation :: LocationLDT ItemLink ComposedItem -> UseFocus
+useLocation loc 
+    | isJust $ loc ^? locLDT . ldtValue . _1 . itUse . uequipEffect = UseFromLocation
+    | isJust $ loc ^? locLDT . ldtValue . _1 . itUse . uaParams . apLinkedProjectile
+        = UseFromLocation
+    | otherwise = UseFromRoot
+
 toggleEquipmentAt :: Int -> Creature -> World -> World
 toggleEquipmentAt invid cr w = case getEquipmentAllocation w of
     DoNotMoveEquipment -> w