module Shader.Bind (
    bufferShaderLayers,
    bufferPokedVBO,
    bufferEBO,
) where

import Control.Lens
import Control.Monad.Primitive
import qualified Data.Vector.Fusion.Stream.Monadic as VFSM
import qualified Data.Vector.Mutable as MV
import qualified Data.Vector.Unboxed.Mutable as UMV
import Foreign hiding (rotate)
--import Control.Monad
import Graphics.GL.Core45
import Shader.Data
import Shader.Parameters

bufferPokedVBO :: VBO -> Int -> IO ()
{-# INLINEABLE bufferPokedVBO #-}
bufferPokedVBO theVBO numVs =
    glNamedBufferSubData
        (_vboName theVBO)
        0
        (fromIntegral $ numVs * _vboVertexBytes theVBO)
        (_vboPtr theVBO)

bufferEBO :: EBO -> Int -> IO ()
bufferEBO ebo numis =
    glNamedBufferSubData
        (ebo ^. eboName)
        0
        (fromIntegral $ glushortSize * numis)
        (ebo ^. eboPtr)

bufferShaderLayers :: MV.MVector (PrimState IO) (Shader, VBO) -> UMV.MVector (PrimState IO) Int -> IO ()
bufferShaderLayers shads counts = MV.imapM_ f shads
  where
    f i shad = do
        let theVBO = snd shad
            stride = _vboVertexBytes theVBO `div` floatSize
        VFSM.mapM_ (g stride theVBO) $ VFSM.enumFromStepN 0 1 6 -- [0..5]
      where
        g stride theVBO lay = do
            numVs <- UMV.unsafeRead counts $ lay * 6 + i
            glNamedBufferSubDataH
                (_vboName theVBO)
                (fromIntegral $ floatSize * stride * numSubElements * lay)
                (fromIntegral $ floatSize * numVs * stride)
                (_vboPtr theVBO `plusPtr` (floatSize * stride * numSubElements * lay))

glNamedBufferSubDataH :: GLuint -> GLintptr -> GLsizeiptr -> Ptr a -> IO ()
glNamedBufferSubDataH = glNamedBufferSubData