Refactor shader loading

src/Geometry.hs

@@ -25,6 +25,7 @@ import Geometry.Vector
 import Geometry.LHS
 --import Geometry.Zone
 
+import Data.Maybe
 import Data.List
 -- | Return a point a distance away from a first point towards a second point.
 -- Does not go past the second point.
@@ -64,6 +65,13 @@ rectNSWE !n !s !w !e = [V2 w n, V2 w s, V2 e s, V2 e n]
 -- | Draw a rectangle around the origin with given height and width
 rectWdthHght :: Float -> Float -> [Point2]
 rectWdthHght w h = rectNSWE h (-h) (-w) w
+
+mirrorXAxis :: [Point2] -> [Point2]
+mirrorXAxis ps = orderPolygon $ ps ++ mapMaybe f ps
+  where
+    f (V2 _ 0) = Nothing
+    f (V2 x y) = Just $ V2 x (-y)
+
 -- | Test whether a point is in a polygon or on the polygon border.
 -- Supposes the points in the
 -- polygon are listed in anticlockwise order.