Factor out wls/crsHit

src/Dodge/WorldEvent/ThingsHit.hs

@@ -25,22 +25,22 @@ thingsHit
     -> Point2    -- ^ Line end point
     -> World 
     -> Stream (Of (Point2, Either Creature Wall)) Identity ()
-thingsHit sp ep w 
+thingsHit sp ep w = void $ S.mergeOn (dist sp . fst)  
-    | sp == ep  = S.each []
+    (S.map (second Left)  (crsHit sp ep w))
-    | otherwise = void $ S.mergeOn (dist sp . fst) crs wls
+    (S.map (second Right) (wlsHit sp ep w))
-  where 
+
-    crs :: Stream (Of (Point2, Either Creature Wall)) Identity ()
+crsHit :: Point2 -> Point2 -> World -> Stream (Of (Point2, Creature)) Identity ()
-    crs = sortStreamOn (dist sp . fst)
+crsHit sp ep
+    | sp == ep  = const mempty
+    | otherwise = sortStreamOn (dist sp . fst)
         . S.mapMaybe 
-            (\cr -> (,Left cr) <$> listToMaybe (intersectCircSeg (_crPos cr) (_crRad cr) sp ep))
+            (\cr -> (, cr) <$> listToMaybe (intersectCircSeg (_crPos cr) (_crRad cr) sp ep))
         . S.each 
-        $ _creatures w
+        . _creatures
-    wls :: Stream (Of (Point2, Either Creature Wall)) Identity ()
+
-    wls = S.map (second Right) 
-        . sortStreamOn (dist sp . fst)
-        . overlapSegWalls sp ep $ wallsAlongLine sp ep w
 thingHit :: Point2 -> Point2 -> World -> Maybe (Point2, Either Creature Wall)
 thingHit sp ep = runIdentity . S.head_ . thingsHit sp ep
+
 {- List objects that appear on a line.
 Can filter out a creature.  -}
 thingsHitExceptCr 
@@ -55,12 +55,9 @@ thingsHitExceptCr (Just cid) sp ep = S.filter crNotCid . thingsHit sp ep
     crNotCid (_,Left cr) = _crID cr /= cid
     crNotCid _ = True
 
-wallsHit
+wlsHit :: Point2 -> Point2 -> World -> Stream (Of (Point2, Wall)) Identity ()
-    :: Point2    -- ^ Line start point
+wlsHit sp ep
-    -> Point2    -- ^ Line end point
+    | sp == ep  = const mempty
-    -> World 
-    -> Stream (Of (Point2, Wall)) Identity ()
-wallsHit sp ep w 
-    | sp == ep  = S.each []
     | otherwise = sortStreamOn (dist sp . fst)
-        . overlapSegWalls sp ep $ wallsAlongLine sp ep w
+        . overlapSegWalls sp ep
+        . wallsAlongLine sp ep