gistfile1.hs

renderPixel :: Int -> Int -> Int -> RayMaker -> World -> Colour Int
--
parMap  rdeepseq
        (\(i,j) -> renderPixel depth i j raymaker world)
        [(i,j) | i <- [0..h-1], j <- [0..w-1]]
--
$> +RTS -N2 -s -RTS ... => 100% cpu usage;

----

map (\(i,j) -> renderPixel depth i j raymaker world)
    [(i,j) | i <- [0..h-1], j <- [0..w-1]]
    `using` parListChunk (w*h `div` 2) rdeepseq
--
$> +RTS -N2 -s -RTS ... => 100-150% cpu usage but slower.

----
data Colour a = Colour !(a, a, a) deriving (Eq, Ord, Show)
type Colours a = [Colour a]

instance NFData (Colour a) where
  rnf (Colour (x,y,z)) = x `seq` y `seq` z `seq` ()