Commit before attempting to allow for non-convex chasm shapes

src/Geometry/Polygon.hs

@@ -80,11 +80,24 @@ pointInOrOnPolygon _ _ = undefined
 
 {- | Test whether a point is strictly inside a polygon.
  Supposes the points in the polygon are listed in anticlockwise order.
+Requires that the polygon is convex.
 -}
 pointInPoly :: Point2 -> [Point2] -> Bool
 pointInPoly !p (x : xs) = all (\l -> uncurry isLHS l p) $ zip (x : xs) (xs ++ [x])
 pointInPoly _ [] = False
 
+inSimplePoly :: Point2 -> [Point2] -> Bool
+inSimplePoly p (x:xs) = foldl' (flip f) True $ zip (x:xs) (xs ++ [x])
+  where
+    f (a,b) = case intersectSegRay a b p (p + V2 1 0) of
+        Nothing -> id
+        Just {} -> not
+inSimplePoly _ [] = False
+
+---- implement Dan Sunday point in polygon algorithm?
+--wnPointPoly :: Point2 -> Point2 -> Point2 -> Int
+--wnPointPoly p x y = 0
+
 circInPolygon :: Point2 -> Float -> [Point2] -> Bool
 circInPolygon !p !r (x : xs) = all f $ zip (x : xs) (xs ++ [x])
   where