Implement texture atlas, details on why it works unclear

src/Shader/AuxAddition.hs

@@ -1,9 +1,11 @@
 module Shader.AuxAddition
     ( addTexture
+    , addTextureArray
     , addUniforms
     ) where
 import Shader.Data
 
+import Data.List.Extra
 import Foreign
 import Codec.Picture
 import qualified Data.Vector.Storable as V
@@ -29,6 +31,31 @@ addTexture texturePath shad = do
     textureFilter Texture2D $= ((Linear',Just Linear') , Nearest)
     return $ shad & shaderTexture ?~ ShaderTexture {_textureObject = textureOb}
 
+addTextureArray :: String -> FullShader -> IO (FullShader)
+addTextureArray texturePath shad = do
+    Right cmap <- readImage texturePath
+    let tex = convertRGBA8 cmap
+    textureOb <- genObjectName
+    textureBinding Texture2DArray $= Just textureOb
+    let texData = tilesToLine 128 32 8 . 
+            V.toList $ imageData tex
+        --wtex = fromIntegral $ imageWidth  tex
+        --htex = fromIntegral $ imageHeight tex
+    withArray texData $ \ptr -> do
+        texImage3D Texture2DArray NoProxy 0 RGBA8 (TextureSize3D 32 32 64) 0 
+                        (PixelData RGBA UnsignedByte ptr)
+    textureFilter Texture2DArray $= ((Linear',Just Linear') , Linear')
+    generateMipmap' Texture2DArray
+    return $ shad & shaderTexture ?~ ShaderTexture {_textureObject = textureOb}
+
+-- I am completely unclear on why this works with its current parameters
+tilesToLine 
+    :: Int -- ^ Tile width
+    -> Int -- ^ Tile height
+    -> Int -- ^ Number of tiles per line
+    -> [a]
+    -> [a]
+tilesToLine w h n = concat . concat . transpose . chunksOf n . chunksOf w
 
 addUniforms :: [String] -> FullShader -> IO (FullShader)
 addUniforms uniStrings shad = do