Add intersecting beams

src/Dodge/Particle/Damage.hs

@@ -1,10 +1,12 @@
 module Dodge.Particle.Damage where
 import Dodge.Data
 import Geometry
+import LensHelp
 
 import System.Random
 import Control.Monad.State
 
+-- TODO unify particle position in a sensible manner
 spawnAtBulDams :: (Point2 -> State StdGen Particle)
     -> Particle -> Point2 -> [Damage]
 spawnAtBulDams thespawn bt p =
@@ -21,7 +23,9 @@ simpleDam dt amount bt p =
     [ Damage dt amount sp p ep NoDamageEffect
     ]
   where
-    sp = head $ _ptTrail bt
+    sp = case bt ^? ptTrail of
+        Nothing -> _ptPos bt
+        Just xs -> head xs
     bulVel = _ptVel bt
     ep = sp +.+ bulVel