Refactor bullet particles

src/Dodge/Particle/Bullet/Update.hs

@@ -0,0 +1,34 @@
+{-
+Bullet update.
+ -}
+module Dodge.Particle.Bullet.Update
+    where
+import Dodge.Data
+--import Dodge.Base
+import Dodge.WorldEvent.ThingsHit
+--import Picture
+import Geometry
+
+import Control.Lens
+--import Data.Maybe
+--import Data.List
+--import Data.Bifunctor
+--import qualified Data.IntMap.Strict as IM
+
+{-
+Update for a generic bullet.
+-}
+mvGenBullet' :: World -> Particle -> (World, Maybe Particle)
+mvGenBullet' w bt 
+    | t <= 0 = (w, Nothing)
+    | t < 4  = (w, Just $ set btPassThrough' Nothing
+                        $ set btTrail' (p:p:ps)
+                        $ set btTimer' (t-1) bt                      
+               )
+    | otherwise = hiteff bt (thingsHitExceptCr mcr p (p +.+ vel) w) w
+  where 
+    mcr     = _btPassThrough' bt
+    (p:ps)  = _btTrail' bt
+    vel     = _btVel' bt
+    hiteff  = _btHitEffect' bt
+    t       = _btTimer' bt