1 files changed, 28 insertions, 10 deletions
diff --git a/src/Vivant/Terrain.hs b/src/Vivant/Terrain.hs
index 3099177..befee88 100644
--- a/src/Vivant/Terrain.hs
+++ b/src/Vivant/Terrain.hs
@@ -8,7 +8,7 @@ import qualified Graphics.Rendering.OpenGL as GL
 import SDL (($=))
 import Foreign.Marshal.Alloc (free, malloc)
 import Foreign.Ptr
-import Vivant.Common (vectorSize)
+import Vivant.Common (vectorSize, uncurry3)
 import Foreign.Storable (poke)
 import Linear
 
@@ -16,27 +16,42 @@ data Terrain = Terrain
   {
     terrainWidth :: Int,
     terrainHeight :: Int,
-    terrainGeometry :: [[Int]],
+    terrainGeometry :: [[Float]],
     terrainRenderer :: Renderer
   } deriving (Show)
 
+normal :: Num c => (c, c, c) -> (c, c, c) -> (c, c, c) -> (c, c, c)
+normal a b c =
+  transform $ cross (uncurry3 V3 b ^-^ uncurry3 V3 a) (uncurry3 V3 c ^-^ uncurry3 V3 a)
+  where
+    transform (V3 a b c) = (a, b, c)
+
 partition
-  :: (V.Storable a1, Integral a2, Num a1) => [[a2]] -> V.Vector a1
+  :: (V.Storable a1, Enum a1, Num a1) => [[a1]] -> V.Vector a1
 partition r =
-  V.fromList . fmap fromIntegral . concat . concat .
+  V.fromList . concat . concat .
   fmap (\(e, y) -> fmap (generateP y) $ zip (zip (uncurry zip e) $ tail (uncurry zip e)) [0..])
   $ zip (zip r $ tail r) [0..]
   where
     generateP y (((z1, z2), (z3, z4)), x) =
+      let (n1x, n1y, n1z) = normal (x, y, z1) (x, y+1, z2) (x+1, y, z3)
+          (n2x, n2y, n2z) = normal (x+1, y+1, z4) (x, y+1, z2) (x+1, y, z3)
+      in
       [ x,   y,   z1
+      , -n1x, -n1y, -n1z
       , x,   y+1, z2
+      , -n1x, -n1y, -n1z
       , x+1, y,   z3
+      , -n1x, -n1y, -n1z
       , x,   y+1, z2
+      , n2x, n2y, n2z
       , x+1, y,   z3
+      , n2x, n2y, n2z
       , x+1, y+1, z4
+      , n2x, n2y, n2z
       ]
 
-initTerrain :: [[Int]] -> GL.Program -> IO Terrain
+initTerrain :: [[Float]] -> GL.Program -> IO Terrain
 initTerrain g p = do
   vao <- GL.genObjectName
   GL.bindVertexArrayObject $= Just vao
@@ -48,17 +63,20 @@ initTerrain g p = do
   V.unsafeWith g' $ \ptr ->
     GL.bufferData GL.ArrayBuffer $= (vectorSize g', castPtr ptr, GL.StaticDraw)
 
-  setVertexAttribute p "position" 3 0 0
+  setVertexAttribute p "position" 3 6 0
+  setVertexAttribute p "normal" 3 6 3
 
   GL.bindVertexArrayObject $= Nothing
 
+  let h = length g
+      w = length (head g)
+      modelMatrix = mkTransformation (axisAngle (V3 0 0 0) 0)
+        (V3 (- fromIntegral w / 2) (- fromIntegral h / 2) 0)
+
   modelP <- malloc
-  let modelMatrix = mkTransformation (axisAngle (V3 0 0 0) 0) (V3 (-2.5) (-2.5) 0)
   poke modelP modelMatrix
 
-  let h = length g
-      w = length (head g)
-  return $ Terrain w h g (Renderer (Just p) (Just vao) modelP 72)
+  return $ Terrain w h g (Renderer (Just p) (Just vao) modelP ((w + 2) * (h + 2) * 8))
 
 destroyTerrain :: Terrain -> IO ()
 destroyTerrain t =