module Shader (
    freeShaderPointers',
    drawShaderLay,
    shadVBOptr,
    drawShader,
) where

import Control.Lens
import Control.Monad
import Control.Monad.Primitive
import qualified Data.Vector.Unboxed.Mutable as UMV
import Foreign
import Graphics.GL.Core45
import Shader.Data
import Shader.Parameters

drawShaderLay :: Int -> UMV.MVector (PrimState IO) Int -> Int -> (Shader, VBO) -> IO ()
{-# INLINE drawShaderLay #-}
drawShaderLay l countsVector shadIn fs = do
    i <- UMV.read countsVector shadIn
    glUseProgram (_shaderUINT $ fst fs)
    glBindVertexArray $ fs ^. _1 . shaderVAO . vaoName
    zipWithM_ (\ti -> glBindTextureUnit ti . _unTO) [0 ..] (fs ^. _1 . shaderTextures)
    glDrawArrays
        (_unPrimitiveMode $ _shaderPrimitive $ fst fs)
        (fromIntegral $ l * numSubElements)
        (fromIntegral i)

drawShader :: Shader -> Int -> IO ()
{-# INLINE drawShader #-}
drawShader fs i = do
    glUseProgram (_shaderUINT fs)
    glBindVertexArray $ fs ^. shaderVAO . vaoName
    zipWithM_ (\ti -> glBindTextureUnit ti . _unTO) [0..] (fs ^. shaderTextures)
    glDrawArrays
        (_unPrimitiveMode $ _shaderPrimitive fs)
        0
        (fromIntegral i)

freeShaderPointers' :: (Shader, VBO) -> IO ()
freeShaderPointers' = free . _vboPtr . snd

shadVBOptr :: (Shader, VBO) -> Ptr Float
{-# INLINE shadVBOptr #-}
shadVBOptr = _vboPtr . snd