module Shader.Bind
    ( bindShaderLayers
    , bindShaderBuffers
    , bindShaderBuffers'
    , bindShader
    ) where
import Shader.Data
import Shader.Parameters

import Graphics.Rendering.OpenGL hiding (Line,translate,scale,imageHeight,Polygon,Color,T)
import Foreign hiding (rotate)
import qualified Data.Vector.Unboxed.Mutable as UMV
import qualified Data.Vector.Mutable as MV
import qualified Data.Vector.Fusion.Stream.Monadic as VFSM
import Control.Monad.Primitive
import Control.Monad
import Graphics.GL.Core45

bindArrayBuffers :: Int -> VBO -> IO ()
{-# INLINABLE bindArrayBuffers #-}
bindArrayBuffers numVs theVBO = do
    glBindBuffer GL_ARRAY_BUFFER (_vboName theVBO)
    bufferSubData 
        ArrayBuffer 
        WriteToBuffer 
        0 
        (fromIntegral $ floatSize * numVs * sum (_vboAttribSizes theVBO)) 
        (_vboPtr theVBO)

bindShaderLayers :: MV.MVector (PrimState IO) FullShader' -> UMV.MVector (PrimState IO) Int -> IO ()
bindShaderLayers shads counts = MV.imapM_ f shads
  where
    f i shad = do
        let theVBO = _vaoVBO $ _shadVAO' shad
            stride = sum $ _vboAttribSizes theVBO
        glBindBuffer GL_ARRAY_BUFFER (_vboName $ theVBO)
        VFSM.mapM_ (g stride theVBO) $ VFSM.enumFromStepN 0 1 6 -- [0..5]
        --S.mapM_ (g stride theVBO) $ S.each [0..5]
        
      where
        g stride theVBO lay = do
            numVs <- UMV.unsafeRead counts $ lay * 6 + i
            bufferSubData
                ArrayBuffer 
                WriteToBuffer 
                (fromIntegral $ floatSize * stride * numSubElements * lay)
                (fromIntegral $ floatSize * numVs * stride)
                (_vboPtr theVBO `plusPtr` (floatSize * stride * numSubElements * lay))

bindShader :: MV.MVector (PrimState IO) FullShader' -> UMV.MVector (PrimState IO) Int -> IO ()
bindShader shads counts = MV.imapM_ f shads
  where
    f i shad = UMV.read counts i >>= flip bindArrayBuffers (_vaoVBO . _shadVAO' $ shad)

bindShaderBuffers :: [FullShader'] -> [Int] -> IO ()
bindShaderBuffers = zipWithM_ f
  where 
    f fs i = bindArrayBuffers i $ _vaoVBO $ _shadVAO' fs

bindShaderBuffers' :: [FullShader'] -> [Int] -> IO ()
bindShaderBuffers' = zipWithM_ f
  where 
    f fs i = bindArrayBuffers i $ _vaoVBO $ _shadVAO' fs