Initial pass at shadows from level geometry

src/Dodge/Data.hs

@@ -30,6 +30,7 @@ import Dodge.World.Trigger.Data
 import Data.Preload
 import Picture.Data
 import Geometry.Data
+import Polyhedra.Data
 import Sound.Data
 import qualified DoubleStack as DS
 
@@ -74,7 +75,7 @@ data World = World
     , _soundQueue           :: [(Int,Int16)]
     , _sounds               :: M.Map SoundOrigin Sound
     , _decorations          :: IM.IntMap Picture
-    , _foregroundDecorations :: [Picture]
+    , _foregroundDecorations :: [Polyhedra]
     , _corpses              :: IM.IntMap (IM.IntMap [Corpse])
     , _clickMousePos        :: (Float,Float)
     , _pathGraph            :: ~(Gr Point2 Float)