Revert "Turn Shape into a stream"

This reverts commit c7e720248d.

src/Shape.hs

@@ -25,7 +25,7 @@ import qualified Data.Vector.Fusion.Stream.Monadic as VS
 
 emptySH :: Shape
 {-# INLINE emptySH #-}
-emptySH = VS.empty
+emptySH = mempty
 
 -- - approximate a circle by a polygon with n*2 points of radius x
 polyCirc :: Int -> Float -> [Point2]
@@ -45,7 +45,7 @@ prismPoly
     -> [Point3] 
     -> Shape
 {-# INLINE prismPoly #-}
-prismPoly upps downps = VS.singleton $ ShapeObj (TopPrism n) (VS.fromList $ f upps downps)
+prismPoly upps downps = [ShapeObj (TopPrism n) (VS.fromList $ f upps downps)]
   where
     n = length upps
     f (a:as) (b:bs) = g a:g b:f as bs
@@ -58,7 +58,7 @@ upperPrismPoly
     -> [Point2] 
     -> Shape
 {-# INLINE upperPrismPoly #-}
-upperPrismPoly h ps = VS.singleton $ ShapeObj (TopPrism n) (VS.fromList $ f ps)
+upperPrismPoly h ps = [ShapeObj (TopPrism n) (VS.fromList $ f ps)]
   where
     n = length ps
     g h' (V2 x y) = pairToSV (V3 x y h', black)
@@ -70,7 +70,7 @@ upperPrismPolyHalf
     -> [Point2] 
     -> Shape
 {-# INLINE upperPrismPolyHalf #-}
-upperPrismPolyHalf h ps = VS.singleton $ ShapeObj (TopPrism n) (VS.fromList $ f upps downps)
+upperPrismPolyHalf h ps = [ShapeObj (TopPrism n) (VS.fromList $ f upps downps)]
   where
     n = length ps
     upps = map f' ps
@@ -94,7 +94,7 @@ overColSH = fmap . overColObj
 
 overPosSHI :: (Point3 -> Point3) -> Shape -> Shape
 {-# INLINE overPosSHI #-}
-overPosSHI = VS.map . overPosObj
+overPosSHI = fmap . overPosObj
 
 translateSH :: Point3 -> Shape -> Shape
 {-# INLINE translateSH #-}