Improve texture loading performance

src/Preload/Render.hs

@@ -90,7 +90,8 @@ preloadRender = do
                 >>= addTexture "data/texture/grayscaleDirt.png"
 ---- texture array shader
     textArrayShad <- makeShader "texture/array" [vert,frag] [3,3] ETriangles
-        >>= addTextureArray "data/texture/ayene_wooden_floor.png"
+        >>= addTextureArray "data/texture/ayene_wooden_floor_transformed.png"
+      --  >>= addTextureArray "data/texture/ayene_wooden_floor.png"
     -- bind fixed vertex data
     bindShaderBuffers [fsShad,fullscreenAlphaHalveShad] [4,4]
     framebuf2 <- setupTextureFramebuffer 800 600

src/Shader/AuxAddition.hs

@@ -4,11 +4,12 @@ module Shader.AuxAddition
     , vaddTextureNoFilter
     , addTextureArray
     , addUniforms
+    , tilesToLine -- ^ kept in case it is needed in the future
     ) where
 import Shader.Data
 
 import Data.List.Extra
-import Foreign
+--import Foreign
 import Codec.Picture
 import qualified Data.Vector.Storable as V
 import Control.Lens
@@ -41,8 +42,7 @@ vaddTextureNoFilter texturePath shad = do
     textureOb <- genObjectName
     textureBinding Texture2D $= Just textureOb
     textureFilter Texture2D $= ((Nearest,Nothing) , Nearest)
-    let texData = V.toList $ imageData tex
-        wtex = fromIntegral $ imageWidth  tex
+    let wtex = fromIntegral $ imageWidth  tex
         htex = fromIntegral $ imageHeight tex
     glTexStorage2D GL_TEXTURE_2D 1 GL_RGBA8 wtex htex
     --withArray texData $ \ptr -> do
@@ -57,25 +57,29 @@ addTextureNoFilter texturePath shad = do
     textureOb <- genObjectName
     textureBinding Texture2D $= Just textureOb
     textureFilter Texture2D $= ((Nearest,Nothing) , Nearest)
-    let texData = V.toList $ imageData tex
-        wtex = fromIntegral $ imageWidth  tex
+    let wtex = fromIntegral $ imageWidth  tex
         htex = fromIntegral $ imageHeight tex
     glTexStorage2D GL_TEXTURE_2D 1 GL_RGBA8 wtex htex
-    --withArray texData $ \ptr -> do
     V.unsafeWith (imageData tex) $ \ptr -> do
         glTexSubImage2D GL_TEXTURE_2D 0 0 0 wtex htex GL_RGBA GL_UNSIGNED_BYTE ptr
     return $ shad & shaderTexture ?~ ShaderTexture {_textureObject = textureOb}
 
+-- | for transforming a 256x256 image containing 64 tiles of 16x16 pixels into
+-- an image that was directly readable by glTexSubImage3D, used the
+-- transformation tilesToLine 8 128 on the underlying pixels.
 addTextureArray :: String -> FullShader -> IO FullShader
 addTextureArray texturePath shad = do
     textureOb <- genObjectName
     textureBinding Texture2DArray $= Just textureOb
     Right cmap <- readImage texturePath
     let tex = convertRGBA8 cmap
-    let texData = tilesToLine 128 8 . 
-            V.toList $ imageData tex
+    --let texData = tilesToLine 8 128 . 
+    --let texData = tilesToLine 8 128 . 
+    --        V.toList $ imageData tex
     glTexStorage3D GL_TEXTURE_2D_ARRAY 3 GL_RGBA8 32 32 64
-    withArray texData $ \ptr -> do
+    --writePng "atest.png" ((Image 256 256 (V.fromList texData)) :: Image PixelRGBA8)
+    --withArray texData $ \ptr -> do
+    V.unsafeWith (imageData tex) $ \ptr -> do
         --glTexSubImage3D GL_TEXTURE_2D_ARRAY 0 0 0 0 32 32 64 GL_RGBA GL_UNSIGNED_BYTE ptr
         glTexSubImage3D GL_TEXTURE_2D_ARRAY 0 0 0 0 32 32 64 GL_RGBA GL_UNSIGNED_BYTE ptr
     textureFilter Texture2DArray $= ((Linear',Just Linear') , Linear')
@@ -88,14 +92,7 @@ tilesToLine
     -> Int -- ^ Parameter b
     -> [a]
     -> [a]
-tilesToLine w n = concat . concat . transpose . chunksOf n . chunksOf w
-tilesToLineV
-    :: Int -- ^ Parameter a
-    -> Int -- ^ Parameter b
-    -> V.Vector a
-    -> V.Vector a
-tilesToLineV w n = undefined
-
+tilesToLine n w = concat . concat . transpose . chunksOf n . chunksOf w
 
 addUniforms :: [String] -> FullShader -> IO FullShader
 addUniforms uniStrings shad = do