(defn update-spectrum [mesh]
  (s/>->> [:p] [:spectrum-data]
       #(if (and (:updated %2) (minim/playing? %1))
          (let
            [data (:data %2)
             l-data (:left data)
             r-data (:right data)
             vertices (persistent! (reduce (fn [c d] (conj! c (spec-x d (nth l-data d)) (spec-y d (nth r-data d)) 0)) (transient []) (range 360)))
             ]
          (update-vertex-buffer! mesh vb-type-position vertices)
            (s/ag!! :spectrum-data (fn [_] {:updated false}))
            (start-spectrum-data-gatherer %1)))))


(defn update-vertex-buffer! [mesh|geom vb-type lazy-data]
  (let [data (apply concat lazy-data)
        ;_ (println "data =" lazy-data)
        vb (vertex-buffer?? mesh|geom vb-type)
        nio-buffer (.getData vb)]
    (if (> (count data) (.capacity nio-buffer))
      ; if the existing buffer length is shorter than data length, re-create the buffer
      (let
        [mesh (resolve-mesh mesh|geom)
         new-buffer (create-float-buffer data)]
        (vertex-buffer! mesh vb-type 3 new-buffer))
      ; if the existing buffer length is enough for data, re-use the buffer
      (do
        (.rewind nio-buffer)
        (.updateData vb (create-float-buffer data)))))