pituicat/src/Texture.hs
2020-10-12 06:08:33 +02:00

71 lines
1.7 KiB
Haskell

module Texture where
import Data.Vector.Storable as VS
import qualified Graphics.Rendering.OpenGL as GL
import SDL (($=), get)
import Codec.Picture
import Codec.Picture.Extra
import Linear
import Foreign
import Foreign.Ptr
-- internal imports
import Classes.Bindable
import Types.Texture
newTexture :: FilePath -> GL.GLuint -> IO Texture
newTexture fp slot = do
-- read in image from filesystem
img <- flipVertically <$> convertRGBA8 <$>
either (error $ "reading image file " <> fp <> " failed!") id <$>
readImage fp
-- extract the raw pointer from vector
unsafeWith (imageData img) $ \ptr -> do
-- create texture object
tex <- Texture
<$> GL.genObjectName
<*> (pure $ GL.TextureUnit slot)
-- <*> (pure fp)
let dimensions = fromIntegral <$> V2 (imageWidth img) (imageHeight img)
-- <*> (pure $ componentCount (VS.head $ imageData img))
data_ = castPtr ptr
-- bind texture
bind tex
-- set texture parameters
GL.textureFilter GL.Texture2D $= ((GL.Linear', Nothing), GL.Linear')
GL.textureWrapMode GL.Texture2D GL.S $= (GL.Repeated, GL.Clamp)
GL.textureWrapMode GL.Texture2D GL.T $= (GL.Repeated, GL.Clamp)
-- put data into GPU memory
loadTexture tex dimensions data_
-- unbind texture
unbind tex
-- -- throw away the data on the CPU side
-- free (texData tex)
-- pass texture object out
return tex
loadTexture :: Texture -> V2 GL.GLsizei -> Ptr () -> IO ()
loadTexture tex dimensions data_ =
let (V2 w h) = dimensions
in GL.texImage2D
GL.Texture2D
GL.NoProxy
0
GL.RGBA'
(GL.TextureSize2D w h)
0
(GL.PixelData GL.RGBA GL.UnsignedByte data_)