Small optimisations

src/Dodge/Base.hs

@@ -18,6 +18,7 @@ import Geometry
 --import Picture
 import qualified IntMapHelp as IM
 
+import Data.Foldable
 import Control.Lens
 --import Control.Monad.State
 --import Data.List
@@ -88,7 +89,19 @@ wallsOnCirc p r = IM.filter f
     f wl = uncurry circOnSeg (_wlLine wl) p r
 
 wallsOnScreen :: World -> IM.IntMap Wall
-wallsOnScreen w = wallsNearZones (zoneOfScreen w) w
+wallsOnScreen w -- = wallsNearZones (zoneOfScreen w) w
+    = foldl' (flip $ IM.union . \i -> innerFold (f i (_wallsZone w))) IM.empty xs
+  where 
+    innerFold m = foldl' (flip $ IM.union . \ j -> f j m) IM.empty ys
+
+    f i m = case IM.lookup i m of 
+        Just val -> val
+        _        -> IM.empty
+    (x,y) = zoneOfPoint $ _cameraCenter w
+    n = ceiling (wh / (_cameraZoom w * zoneSize))
+    wh = max (getWindowX w) (getWindowY w)
+    xs = [x - n .. x + n]
+    ys = [y - n .. y + n]
 
 allWalls :: World -> IM.IntMap Wall
 allWalls w = IM.unions $ concatMap IM.elems $ IM.elems $ _wallsZone w