Simplify room out/in placements

src/Dodge/Room/Door.hs

@@ -9,6 +9,7 @@ import Dodge.Default.Room
 import Dodge.Placement.Instance
 import Dodge.RoomLink
 import Geometry
+import Control.Lens
 
 door :: Room
 door =
@@ -28,17 +29,19 @@ door =
         ]
 
 triggerDoorRoom :: Int -> Room
-triggerDoorRoom inplid =
+triggerDoorRoom i =
     defaultRoom
         { _rmPolys = [rectNSWE 40 0 0 40]
         , _rmLinks = [uncurry outLink (V2 20 35, 0), uncurry inLink (V2 20 5, pi)]
         , _rmPath = doublePairSet (V2 20 35, V2 20 5)
-        , _rmInPmnt = [InPlacement f inplid]
+        , _rmInPmnt = [f]
         , _rmName = "triggerDoorRoom"
         -- door extends into side walls (for shadows as rendered 12/03/21)
         -- note no bounds
         }
   where
-    f _ (pmnt : _) = putDoubleDoor DoorObstacle (switchWallCol red) (cond pmnt) (V2 0 20) (V2 40 20) 2
-    f _ _ = error "tried to put a door using an empty placement list"
+    f gw = fromMaybe (error "tried to put a door using an empty placement list") $ do
+        pmnt <- gw ^? genPmnt . ix i . _head
+        return $ putDoubleDoor 
+            DoorObstacle (switchWallCol red) (cond pmnt) (V2 0 20) (V2 40 20) 2
     cond pmnt = WdTrig $ fromJust (_plMID pmnt)