Add explicit layer datatype

src/Picture.hs

@@ -57,19 +57,19 @@ polygon :: [Point2] -> Picture
 {-# INLINE polygon #-}
 polygon = map f . polyToTris
   where
-    f (V2 x y) = Verx (V3 x y 0) black [] (LayNum 0) polyNum
+    f (V2 x y) = Verx (V3 x y 0) black [] BottomLayer polyNum
 
 polygonZ :: [Point2] -> Float -> Picture
 {-# INLINE polygonZ #-}
 polygonZ ps z = map (f . zeroZ) $ polyToTris ps
   where
-    f pos = Verx pos black [z] (LayNum 0) polyzNum
+    f pos = Verx pos black [z] BottomLayer polyzNum
 
 polygonCol :: [(Point2,RGBA)] -> Picture
 {-# INLINE polygonCol #-}
 polygonCol = polyToTris . map f
   where
-    f (V2 x y,col) = Verx (V3 x y 0) col [] (LayNum 0) polyNum
+    f (V2 x y,col) = Verx (V3 x y 0) col [] BottomLayer polyNum
 
 poly3 :: [Point3] -> Picture
 {-# INLINE poly3 #-}
@@ -79,7 +79,7 @@ poly3Col :: [(Point3,RGBA)] -> Picture
 {-# INLINE poly3Col #-}
 poly3Col = map f . polyToTris
   where
-    f (pos,col) = Verx pos col [] (LayNum 0) polyNum
+    f (pos,col) = Verx pos col [] BottomLayer polyNum
 
 -- note that much of work computing the width of the bezier curve is done here
 bezierQuad :: Color -> Color -> Float -> Float -> Point2 -> Point2 -> Point2 -> Picture
@@ -118,7 +118,7 @@ bezierQuad cola colc ra rc a b c
 bzhelp :: [(Point2, Point4, Point2, Point2)] -> Picture
 bzhelp = map f
   where
-    f (V2 x y,col,V2 a b,V2 c d) = Verx (V3 x y 0) col [a,b,c,d] (LayNum 0) bezNum
+    f (V2 x y,col,V2 a b,V2 c d) = Verx (V3 x y 0) col [a,b,c,d] BottomLayer bezNum
 
 -- given a one and two zeros of a linear function over x and y,
 -- determine the function
@@ -166,11 +166,11 @@ addDepth :: Float -> Picture -> Picture
 addDepth d = map $ overPos (\(V3 x y z) -> V3 x y (z+d))
 
 -- TODO change the Int here to a dedicated type
-setLayer :: Int -> Picture -> Picture
+setLayer :: Layer -> Picture -> Picture
 {-# INLINE setLayer #-}
 setLayer i = map f
   where
-    f v = v {_vxLayer = LayNum i}
+    f v = v {_vxLayer = i}
 
 scale3 :: Float -> Float -> Point3 -> Point3
 {-# INLINE scale3 #-}
@@ -215,7 +215,7 @@ circleSolidCol colC colE r = map f
     ,(V3   r  (-r) 0, black)
     ]
   where
-    f (pos,col) = Verx pos col [] (LayNum 0) ellNum
+    f (pos,col) = Verx pos col [] BottomLayer ellNum
 
 circle :: Float -> Picture
 {-# INLINE circle #-}
@@ -233,7 +233,7 @@ text :: String -> Picture
 {-# INLINE text #-}
 text = map f . stringToList
   where
-    f (pos,col,V2 a b) = Verx pos col [a,b] (LayNum 0) textNum
+    f (pos,col,V2 a b) = Verx pos col [a,b] BottomLayer textNum
 
 line :: [Point2] -> Picture
 {-# INLINE line #-}
@@ -326,7 +326,7 @@ thickArcHelp startA endA rad wdth = map f
     (V2 xb yb) = rotateV (0.5 * (startA + endA)) (V2 (rad * sqrt 2) 0)
     --(V2 xb yb) = rotateV (0.5 * (startA + endA)) (V2 (rad * 2) 0)
     (V2 xc yc) = rotateV endA (V2 rad 0)
-    f (pos,col,V3 a b c) = Verx pos col [a,b,c] (LayNum 0) arcNum
+    f (pos,col,V3 a b c) = Verx pos col [a,b,c] BottomLayer arcNum
 
 
 -- Currently the lens version is much slower