pituicat/src/Types/Texture.hs

86 lines
2 KiB
Haskell

module Types.Texture where
import SDL (($=), get)
import qualified Graphics.Rendering.OpenGL as GL
import SDL (($=), get)
import Codec.Picture
import Codec.Picture.Extra
import Data.Vector.Storable (unsafeWith)
import Linear
import Foreign
import Foreign.Ptr
-- internal imports
import Classes.Graphics.Bindable
data Texture = Texture
{ textureId :: GL.TextureObject
, textureSlot :: GL.TextureUnit
}
deriving (Eq, Show)
instance Bindable Texture where
bind t = do
GL.activeTexture $= textureSlot t
GL.textureBinding GL.Texture2D $= Just (textureId t)
unbind t = GL.textureBinding GL.Texture2D $= Nothing
newTexture :: FilePath -> GL.GLuint -> IO (V2 Word, Texture)
newTexture fp slot = do
-- read in image from filesystem
img <- flipVertically <$> convertRGBA8 <$>
either
(\err -> error $ "reading image file " <> fp <> " failed: " <> err)
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.Repeat)
GL.textureWrapMode GL.Texture2D GL.T $= (GL.Repeated, GL.Repeat)
-- put data into GPU memory
loadTexture tex dimensions data_
-- unbind texture
unbind tex
-- pass texture object out
return (fmap fromIntegral dimensions, 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_)