module Camera (Camera (..), makeCamera) where

import Linear.V3
import Linear.Vector

data Camera = Camera {origin :: V3 Double, lowerLeft :: V3 Double, horizontal :: V3 Double, vertical :: V3 Double}

makeCamera :: V3 Double -> Double -> Double -> Double -> Camera
makeCamera o viewWidth viewHeight focalLength = do
  let horizontal = V3 viewWidth 0.0 0.0
  let vertical = V3 0.0 viewHeight 0.0
  let focalVec = V3 0.0 0.0 focalLength
  let lowerLeft = o ^-^ (horizontal ^/ 2) ^-^ (vertical ^/ 2) ^-^ focalVec
  Camera o lowerLeft horizontal vertical