Add check to cylinder segment collision, break rocket projectiles

src/Geometry/Intersect.hs

@@ -360,24 +360,21 @@ intersectCircLine c r x y =
     f :: Float -> Point2
     f a = x + (a *.* (y - x))
 
-intersectCylSeg ::
-    Point3 ->
-    Float ->
-    Float ->
-    Point3 ->
-    Point3 ->
+intersectCylSeg :: Point3 -> Float -> Float -> Point3 -> Point3 ->
     (Maybe (Point3, Point3), Maybe (Point3, Point3))
 intersectCylSeg p r h s e = fromMaybe (Nothing, Nothing) $ do
     (a, b) <- intersectCircLineAlong (p ^. _xy) r (s ^. _xy) (e ^. _xy)
     return (f min a, f max b)
   where
-    mtopx = intersectLinePlaneAlong s e (V3 0 0 h) (V3 0 0 1)
-    mbotx = intersectLinePlaneAlong s e (V3 0 0 0) (V3 0 0 1)
+    mtopx = intersectLinePlaneAlong s e (V3 0 0 (h + p ^. _z)) (V3 0 0 1)
+    mbotx = intersectLinePlaneAlong s e (V3 0 0 (p^._z)) (V3 0 0 1)
     v = e - s
     f mm a = do
         let x = s + a *.*.* v
         if x ^. _z < (h + p ^. _z) && x ^. _z > (p ^. _z)
-            then return (x, v & _xy %~ reflectInNormal (x ^. _xy - p ^. _xy))
+            then do
+                guard $ a >= 0 && a < 1
+                return (x, v & _xy %~ reflectInNormal (x ^. _xy - p ^. _xy))
             else do
                 topx <- mtopx
                 botx <- mbotx