Converted from roc to curvature

lib/Petzval/Optics.hs

@@ -16,6 +16,7 @@ module Petzval.Optics
   , outsideRadius
   , material
   , roc
+  , curvature
   , liftFp
   , specialize, bake
   ) where
@@ -59,7 +60,7 @@ data Element mat fp =
   -- | Refractive surface
   Surface { _thickness :: fp
           , _outsideRadius :: fp
-          , _roc :: fp
+          , _curvature :: fp
           , _material :: mat
           }
   -- | Aperture stop
@@ -67,9 +68,14 @@ data Element mat fp =
       _thickness :: fp
       , _outsideRadius :: fp
       }
+  -- | Imaging plane. This is a hack to make sure that rays go all the way to the target plane
+  | ImagingPlane { _thickness :: fp }
                     deriving (Show)
 makeLenses ''Element
 
+roc :: Fractional fp => Traversal' (Element mat fp) fp
+roc = curvature . iso (1/) (1/)
+
 -- | Determine if an element is a stop
 isStop :: Element mat a -> Bool
 isStop Stop{} = True
@@ -82,7 +88,7 @@ isSurface _ = False
 -- | Translate a lens element from one FP type to another. E.g., can be used to convert from scalars to the types in an automatic differentiation tool.
 liftFp :: (Applicative f) => (fp -> f fp') -> Element m fp -> f (Element m fp')
 liftFp inj (s@Stop{_thickness, _outsideRadius}) = Stop <$> inj _thickness <*> inj _outsideRadius
-liftFp inj (s@Surface{_thickness, _outsideRadius, _roc, _material}) = Surface <$> inj _thickness <*> inj _outsideRadius <*> inj _roc <*> pure _material
+liftFp inj (s@Surface{_thickness, _outsideRadius, _curvature, _material}) = Surface <$> inj _thickness <*> inj _outsideRadius <*> inj _curvature <*> pure _material
 {-# INLINE liftFp #-}
 
 -- | Specialize a system for a specific wavelength