Hittables.carp

(deftype (Hittables h) [elts (Array h)])

(defmodule Hittables
  (deftype (CurrentHit f) [hr (Maybe (Hit f))  dist f])

  (defn closest-hit [hs ray t-min t-max]
    (let [closest (fn [cur h]
                    (match (hit h ray t-min @(CurrentHit.dist &cur))
                           (Maybe.Just hr) (let [rt @(Hit.t &hr)]
                                             (CurrentHit.init (Maybe.Just hr) rt))
                           (Maybe.Nothing) cur))
          ]
      @(CurrentHit.hr
        &(Array.reduce
          &closest
          (CurrentHit.init (Maybe.Nothing) t-max)
          (Hittables.elts hs)))))
  )