126 lines
3.2 KiB
Haskell
126 lines
3.2 KiB
Haskell
{-# LANGUAGE TypeFamilies #-}
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module Types.Graphics.IndexBuffer where
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import qualified Graphics.Rendering.OpenGL as GL
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import SDL (($=), get)
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import qualified Data.Vector.Storable as VS
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import Control.Monad.Loops (whileM_)
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import Control.Concurent.STM
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import Foreign
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-- internal imports
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import Classes.Graphics.Bindable
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import Classes.Graphics.Buffer
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-- layout of the IndexBuffer data object
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data IndexBuffer = IndexBuffer
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{ iBufId :: TVar GL.BufferObject -- buffer id
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, iBufSize :: TVar GL.GLsizeiptr -- size of data
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-- , iBufData :: Ptr a -- pointer to data
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-- , iBufCount :: GL.GLint -- number of data elements
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}
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-- instanciate typeclass from Buffer and fill in missing implementations
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instance Buffer IndexBuffer where
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type StoreType IndexBuffer = GL.GLuint
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type StoreContainer IndexBuffer = VS.Vector
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target _ = GL.ElementArrayBuffer
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glId = readTVarIO . iBufId
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initialize buf = do
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-- bind the buffer using the default iplementation of the typeclass
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bind buf
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-- fill in the data
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GL.bufferData (target buf) $=
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( iBufSize buf
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, nullPtr
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, GL.DynamicDraw
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)
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-- release the buffer using the default implementation of the typeclass
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unbind buf
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write buf offset dat = do
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currentBufSize <- readTVarIO (iBufSize buf)
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whileM_
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(pure $ offset + VS.length dat * sizeOf (undefined :: StoreType IndexBuffer)
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> currentBufSize) $ do
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allocaArray
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(currentBufSize `div` sizeOf (undefined :: StoreType IndexBuffer))
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$ \ ptr -> do
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GL.bufferSubData
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(target buf)
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GL.ReadFromBuffer
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0
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currentBufSize
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ptr
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expand buf
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bind buf
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GL.bufferSubData
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(target buf)
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GL.WriteToBuffer
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0
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currentBufSize
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ptr
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-- bind buffer, just to be safe
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bind buf
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VS unsafeWith dat $ \ ptr ->
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GL.bufferSubData
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(target buf)
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GL.WriteToBuffer
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(CPtrdiff $ fromIntegral offset)
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(CPtrdiff $ fromIntegral $
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VS.length dat * sizeOf (undefined ::StoreType IndexBuffer))
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ptr
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expand buf = do
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unbind buf
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delete buf
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newId <- GL.genObjectName
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newSize <- (2 *) <$> readTVarIO (iBufSize buf)
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atomically $ do
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writeTvar (iBufId buf) newId
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writeTvar (iBUfSize buf) newSize
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initialize buf
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delete buf = do
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unbind buf
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GL.deleteObjectname ==< (readTVarIO $ vBufId buf)
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instance Bindable (IndexBuffer a) where
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-- bind the buffer
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bind buf = GL.bindBuffer (target buf) $= Just (glId buf)
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-- unbind the buffer
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unbind buf = GL.bindBuffer (target buf) $= Nothing
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newIndexBuffer
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:: Word
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-> IO IndexBuffer -- newly built IndexBuffer data object
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newIndexBuffer initLength = do
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-- create the buffer object in applicative style
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buf <- IndexBuffer
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-- generate the ID
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<$> GL.genObjectName
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-- compute buffer size
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<*> pure (fromIntegral initLength)
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-- -- make pointer out of list
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-- <*> newArray list
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-- -- get count
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-- <*> pure (fromIntegral $ length list)
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-- fill the data in to the buffer
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initialize buf
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-- return the data object
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return buf
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