Draw shape shadows using index buffer

src/Shape.hs

@@ -40,7 +40,7 @@ upperPrismPoly
     -> Shape
 {-# INLINE upperPrismPoly #-}
 upperPrismPoly h ps =
-    ( topFace <> sideFaces
+    ( [ShapeObj ListV (topFace <> sideFaces)]
     , topEdges <> bottomEdges <> sideEdges
     )
   where
@@ -64,7 +64,7 @@ prismPoly
     -> Shape
 {-# INLINE prismPoly #-}
 prismPoly h ps =
-    ( topFace <> bottomFace <> sideFaces
+    ( [ShapeObj ListV (topFace <> bottomFace <> sideFaces)]
     , topEdges <> bottomEdges <> sideEdges
     )
   where
@@ -86,7 +86,7 @@ prismPoly h ps =
 
 flatPoly :: [Point2] -> Shape
 flatPoly ps =
-    ( shVfromList $ polyToTris $ map f ps
+    ( [ShapeObj ListV $ shVfromList $ polyToTris $ map f ps]
     , shEfromList $ concat $ zipWith g ps (tail ps ++ [head ps])
     )
   where
@@ -106,11 +106,11 @@ colorSH col = overCol $ const col
 
 overCol :: (Point4 -> Point4) -> Shape -> Shape
 {-# INLINE overCol #-}
-overCol f = first (fmap $ overColVertex f)
+overCol f = first (fmap $ overColObj f)
 
 overPos :: (Point3 -> Point3) -> Shape -> Shape
 {-# INLINE overPos #-}
-overPos f = bimap (fmap $ overPosVertex f) (fmap f)
+overPos f = bimap (fmap $ overPosObj f) (fmap f)
 
 translateSH :: Point3 -> Shape -> Shape
 {-# INLINE translateSH #-}
@@ -132,10 +132,18 @@ scaleSH :: Point3 -> Shape -> Shape
 {-# INLINE scaleSH #-}
 scaleSH !(V3 a b c) = overPos (\(V3 x y z) -> V3 (x*a) (y*b) (z*c))
 
+overColObj :: (Point4 -> Point4) -> ShapeObj -> ShapeObj
+{-# INLINE overColObj #-}
+overColObj f (ShapeObj st vs) = ShapeObj st (map (overColVertex f) vs)
+
 overColVertex :: (Point4 -> Point4) -> ShapeV -> ShapeV
 {-# INLINE overColVertex #-}
 overColVertex f (ShapeV a b) = ShapeV a (f b)
 
+overPosObj :: (Point3 -> Point3) -> ShapeObj -> ShapeObj
+{-# INLINE overPosObj #-}
+overPosObj f (ShapeObj st vs) = ShapeObj st $ map (overPosVertex f) vs
+
 overPosVertex :: (Point3 -> Point3) -> ShapeV -> ShapeV
 {-# INLINE overPosVertex #-}
 overPosVertex f (ShapeV a b) = ShapeV (f a) b