Minor cleanups

src/Shape.hs

@@ -55,16 +55,12 @@ upperPrismPoly
     -> [Point2] 
     -> Shape
 {-# INLINE upperPrismPoly #-}
-upperPrismPoly h ps = [ShapeObj (TopPrism n) (f upps downps)]
+upperPrismPoly h ps = [ShapeObj (TopPrism n) (f ps)]
   where
     n = length ps
-    upps = map f' ps
-    downps = map f'' ps
-    f (a:as) (b:bs) = a:b:f as bs
-    f [] _ = []
-    f _ [] = []
-    f' (V2 x y) = pairToSV (V3 x y h, black)
-    f'' (V2 x y) = pairToSV (V3 x y 0, black)
+    g h' (V2 x y) = pairToSV (V3 x y h', black)
+    f (x:xs) = g h x : g 0 x : f xs
+    f _ = []
 
 upperPrismPolyHalf
     :: Float    -- ^ height, expected to be strictly positive
@@ -77,8 +73,7 @@ upperPrismPolyHalf h ps = [ShapeObj (TopPrism n) (f upps downps)]
     upps = map f' ps
     downps = map f'' ps
     f (a:as) (b:bs) = a:b:f as bs
-    f [] _ = []
-    f _ [] = []
+    f _ _ = []
     f' (V2 x y) = pairToSV (V3 (0.5 * x) (0.5 * y) h, black)
     f'' (V2 x y) = pairToSV (V3 x y 0, black)