{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE ViewPatterns        #-}

module Main where

import Common.Type
import Config
import Ray.Trace
import Scene.Light
import Scene.Object
import Scene.World

import Data.Array.Accelerate as A
import Data.Array.Accelerate.Data.Colour.Names
import Data.Array.Accelerate.Data.Colour.RGB
import Data.Array.Accelerate.Data.Functor as F
import Data.Array.Accelerate.IO.Codec.BMP
import Data.Array.Accelerate.Linear.V3
import Data.Array.Accelerate.Linear.Vector
--import Data.Array.Accelerate.LLVM.Native as CPU
import Data.Array.Accelerate.LLVM.PTX as PTX
import Data.Array.Accelerate.System.Random.MWC

import Control.Lens
import System.Console.ParseArgs

import qualified Prelude as P


gamma :: Exp Colour -> Exp Colour
gamma (unlift -> (RGB (r :: Exp Float) (g :: Exp Float) (b :: Exp Float))) = lift $ RGB (f r) (f g) (f b)
  where
    reinhard :: Exp Float -> Exp Float
    reinhard x = x/(x + constant 2)

    gamma :: Exp Float -> Exp Float
    gamma = P.flip (A.**) (1 / 2.2)

    f = gamma . reinhard

--  (conf, opts, rest) <- parseArgsIO options defaults header footer
main :: P.IO ()
main = do
  let width = view configWidth defaults
      height = view configHeight defaults

  noise :: Array DIM2 Float <- randomArray (uniformR (0, 1)) (Z :. height :. width)

  let fov = pi / 4
      estimator =
        rotate
--          (union (sphere 1) (cube (1 / P.sqrt 2)))
          (torus 1 0.5)
          (eulerRotation (pi / 3) (pi / 3) (pi / 3))
      eye = constant (V3 0 0 (-5))
      lights =
        A.use $ fromList (Z :. 2)
          [ Light (V3 10 10 (-10)) mistyRose
          , Light (V3 (-10) (-10) (-10)) mintCream
--        , Light (V3 0 0 (-2)) white
          ]

      scene = Scene estimator eye lights (constant white) 1000 0.00001
      eyeDir = castViewRays width height fov
      img =
        map packRGB . map gamma $
        A.zipWith (simpleShading scene) eyeDir (A.use noise)

  writeImageToBMP "render.bmp" (run img)