Replace buggy circle seg intersection with a simpler test

src/Dodge/Projectile/Update.hs

@@ -3,7 +3,7 @@ module Dodge.Projectile.Update (
     updateProjectile,
 ) where
 
-import Control.Lens
+import LensHelp
 import Control.Monad
 import Data.Foldable
 import Data.Maybe
@@ -42,18 +42,44 @@ upProjectile pu pj = case pu of
     -- the following requires that this is at the top of the update list, which is
     -- not ideal
     DestroyPU _ _ -> cWorld . lWorld . projectiles . ix (_prjID pj) . prjUpdates . ix 0 . pjuTimer -~ 1
+    ApplyGravityPU -> applyGravityPU pj
   where
     time = _prjTimer pj
     act st et = time <= st && time >= et
 
+applyGravityPU :: Projectile -> World -> World
+applyGravityPU pj w
+    | newz <= 0 && abs (pj ^. prjZVel) < 1 = w
+        & topj . prjVel %~ decvel
+        & topj . prjSpin %~ decspin
+    | newz < 0 = w & topj . prjZ .~ 0
+        & topj . prjZVel %~ bouncez
+        & topj . prjVel %~ decvel
+        & topj . prjSpin %~ decspin
+        & soundStart (ShellSound (pj ^. prjID)) (pj ^. prjPos) click1S Nothing
+    | otherwise = w & topj . prjZ .~ newz
+        & topj . prjZVel -~ 0.5
+  where
+    topj = cWorld . lWorld . projectiles . ix (pj ^. prjID)
+    bouncez z | z < -1 = -0.5 * z
+        | otherwise = 0
+    decvel v 
+        | magV v > 1 = rotateV (5 * pj ^. prjSpin) $ 0.8 * v
+        | otherwise = 0
+    decspin x
+        | abs x < 0.01 = 0
+        | otherwise = x * 0.9
+    newz = pj ^. prjZ + pj ^. prjZVel
+
 --shellCollisionCheck :: (Projectile -> World -> World) -> Projectile -> World -> World
 shellCollisionCheck :: Maybe (NewInt ItmInt) 
     -> Maybe (NewInt ItmInt) 
     -> Maybe (NewInt ItmInt) 
     -> Projectile -> World -> World
 shellCollisionCheck controlid detid screenid pj w
-    | time > 330 && circOnSomeWall oldPos 4 w = g
-    | time <= 330 && anythingHitCirc 2 oldPos newPos w = g
+--    | time > 330 && circOnSomeWall oldPos 4 w = g
+--    | time <= 330 && anythingHitCirc 2 oldPos newPos w = g
+    | anythingHitCirc 2 oldPos newPos w = g
     | time <= 0 = g
     | otherwise = w
   where