Replace buggy circle seg intersection with a simpler test

src/Dodge/Projectile/Create.hs

@@ -1,5 +1,6 @@
 module Dodge.Projectile.Create (
     createShell,
+    createGShell,
 ) where
 
 import NewInt
@@ -30,7 +31,7 @@ createShell homing mdetonator mscreen payload muz cr w = w
         ?~ Shell
             { _prjPos = pos
             , _prjZ = 20
-            , _prjStartPos = pos
+            , _prjZVel = 0
             , _prjVel = rotateV dir (V2 1 0) + cr ^. crPos - cr ^. crOldPos
             , _prjDraw = homingDrawType homing
             , _prjID = i
@@ -65,3 +66,51 @@ createShell homing mdetonator mscreen payload muz cr w = w
     i = IM.newKey $ w ^. cWorld . lWorld . projectiles
     dir = _crDir cr + _mzRot muz
     pos = _crPos cr +.+ rotateV dir (_mzPos muz)
+
+-- assumes the mscreen is in your inventory
+createGShell :: ProjectileHoming 
+    -> Maybe (NewInt ItmInt) 
+    -> Maybe (NewInt ItmInt) 
+    -> Payload -> Muzzle -> Creature -> World -> World
+createGShell homing mdetonator mscreen payload muz cr w = w
+    & updatescreen
+    & updatedetonator
+    & cWorld . lWorld . projectiles . at i
+        ?~ Shell
+            { _prjPos = pos
+            , _prjZ = 20
+            , _prjZVel = 5
+            , _prjVel = rotateV dir (V2 4 0) + cr ^. crPos - cr ^. crOldPos
+            , _prjDraw = homingDrawType homing
+            , _prjID = i
+            , _prjAcc = rotateV dir (V2 3 0)
+            , _prjDir = dir
+            , _prjSpin = 0
+            , _prjPayload = payload
+            , _prjTimer = 350
+            , _prjUpdates =
+                [ CollisionEffectPU (homing ^? phRemoteID) mdetonator mscreen
+                , TimePU
+                , StartSpinPU 335 (_crID cr) spinamount
+                , RemoteDirectionPU (350 - thrustdelay) 0 homing
+                , ReduceSpinPU (1 - spindrag * 2 / 200)
+                , ApplyGravityPU
+                ]
+            }
+  where
+    spindrag = 1
+    spinamount = 2
+    thrustdelay = 20
+    updatedetonator = fromMaybe id $ do
+        screenid <- mdetonator
+        return $ pointerToItemID screenid . itUse . uaParams
+                . apLinkedProjectile
+                ?~ i
+    updatescreen = fromMaybe id $ do
+        screenid <- homing ^? phRemoteID
+        return $ pointerToItemID screenid . itUse . uaParams
+                . apLinkedProjectile
+                ?~ i
+    i = IM.newKey $ w ^. cWorld . lWorld . projectiles
+    dir = _crDir cr + _mzRot muz
+    pos = _crPos cr +.+ rotateV dir (_mzPos muz)