Move bullets into own data type

src/Dodge/Particle/Bullet/Update.hs

@@ -2,6 +2,7 @@
 {- Bullet update.  -}
 module Dodge.Particle.Bullet.Update
     ( mvBullet
+    , mvSpark
     ) where
 import Dodge.Data
 --import Dodge.Base
@@ -12,15 +13,29 @@ import LensHelp
 
 import Data.Bifunctor
 {- Update for a generic bullet.  -}
-mvBullet :: World -> Particle -> (World, Maybe Particle)
+mvBullet :: World -> Bullet -> (World, Maybe Bullet)
 mvBullet w bt' 
-    | t <= 0 || magV (_ptVel bt) < 1 = (w,Nothing)
+    | t <= 0 || magV (_buVel bt) < 1 = (w,Nothing)
     | otherwise = second (fmap dodrag) $ 
         hiteff bt (thingsHit p (p +.+ vel) w) w
   where
     bt = foldr (\mg b -> _mgField mg mg b) bt' $ _magnets w
+    dodrag = buVel .*.*~ drag
+    drag = _buDrag bt
+    (p:_)   = _buTrail bt
+    vel     = _buVel bt
+    hiteff  = _buHitEff bt
+    t       = _buTimer bt
+
+mvSpark :: World -> Particle -> (World, Maybe Particle)
+mvSpark w bt' 
+    | t <= 0 || magV (_ptVel bt) < 1 = (w,Nothing)
+    | otherwise = second (fmap dodrag) $ 
+        hiteff bt (thingsHit p (p +.+ vel) w) w
+  where
+    bt = bt'
     dodrag = ptVel .*.*~ drag
-    drag = _btDrag bt
+    drag = _ptDrag bt
     (p:_)   = _ptTrail bt
     vel     = _ptVel bt
     hiteff  = _ptHitEff bt