module Shader
    ( freeShaderPointers
    , drawShaderLay
    , shadVBOptr
    , drawShader
    , pokeBindFoldable
    , pokeBindFoldableLayer
    ) where
import Shader.Data
import Shader.Parameters
import Shader.ExtraPrimitive
import Shader.Poke
import Shader.Bind
import Picture.Data

import qualified Data.Vector.Unboxed.Mutable as UMV
import qualified Data.Vector.Mutable as MV
import Control.Monad.Primitive
import Foreign
import Graphics.Rendering.OpenGL hiding (Point,translate,scale,imageHeight)
import Graphics.GL.Core43

drawShaderLay :: Int -> UMV.MVector (PrimState IO) Int -> Int -> FullShader -> IO ()
{-# INLINE drawShaderLay #-}
drawShaderLay l countsVector shadIn fs = do 
    i <- UMV.read countsVector shadIn
    currentProgram $= Just (_shaderProgram fs)
    bindVertexArrayObject $= Just (_vao $ _shaderVAO fs)
    case _shaderTexture fs of 
        Just ShaderTexture{_textureObject = txo}
            -> textureBinding Texture2D $= Just txo
        _   -> return ()
    glDrawArrays (marshalEPrimitiveMode $ _shaderDrawPrimitive fs) (fromIntegral $ l*numSubElements) (fromIntegral i)

drawShader :: FullShader -> Int -> IO ()
{-# INLINE drawShader #-}
drawShader fs i = do 
    currentProgram $= Just (_shaderProgram fs)
    bindVertexArrayObject $= Just (_vao $ _shaderVAO fs)
    case _shaderTexture fs of 
        Just ShaderTexture{_textureObject = txo}
            -> textureBinding Texture2D $= Just txo
        _   -> return ()
    glDrawArrays (marshalEPrimitiveMode $ _shaderDrawPrimitive fs) 0 (fromIntegral i)

freeShaderPointers :: FullShader -> IO ()
freeShaderPointers fs = free $ _vboPtr $ _vaoVBO $ _shaderVAO fs

pokeBindFoldable
    :: MV.MVector (PrimState IO) FullShader
    -> UMV.MVector (PrimState IO) Int
    -> Picture
    -> IO ()
pokeBindFoldable shadV counts m = do
    pokeVerxs shadV counts m
    bindShader shadV counts

pokeBindFoldableLayer
    :: MV.MVector (PrimState IO) FullShader
    -> UMV.MVector (PrimState IO) Int
    -> Picture
    -> IO ()
pokeBindFoldableLayer shadV counts m = do
    pokeLayVerxs shadV counts m
    bindShaderLayers shadV counts

shadVBOptr :: FullShader -> Ptr Float
{-# INLINE shadVBOptr #-}
shadVBOptr = _vboPtr . _vaoVBO . _shaderVAO