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Faux rotating torus testing alpha channels with HSV->RGB color conversion in https://github.com/rm-hull/inkspot. Click the canvas area to toggle between solid color and wireframe. Inspiration: Jerome Herr's http://openprocessing.org/sketch/160303
(ns enchilada.color-vortex
(:require
[jayq.core :refer [show css]]
[enchilada :refer [ctx canvas canvas-size]]
[inkspot.color :refer [coerce red green blue]]
[inkspot.converter :refer [hsv->rgb]]
[big-bang.core :refer [big-bang]]
[big-bang.events.browser :refer [offset-coords]]
[monet.canvas :refer [stroke-style stroke fill-style fill fill-rect
ellipse save restore translate]]))
(def screen-area
(let [[w h] (canvas-size)]
{:x 0 :y 0 :w w :h h}))
(def steps 150)
(def angle (/ (* 2 Math/PI) steps))
(def initial-state { :theta 0 :style :solid })
(defn toggle-style [event world-state]
(assoc world-state
:style (if (= (:style world-state) :wireframe) :solid :wireframe)))
(defn update-state [event world-state]
(update-in world-state [:theta] (partial + (/ 0.0523 3))))
(defn remap [value mina maxa minb maxb]
(+ minb (* (- maxb minb) (/ (- value mina) (- maxa mina)))))
(def color-cache
(mapv #(hsv->rgb [% 0.9 1.0 0.25]) (range 360)))
(def draw-func {
:solid (fn [ctx i shape]
(let [hue (int (remap i 0 steps 0 360))
rgba (color-cache hue)]
(-> ctx (fill-style rgba) (ellipse shape) fill)))
:wireframe (fn [ctx i shape]
(-> ctx (stroke-style "rgba(255,255,255,0.4)") (ellipse shape) stroke)) })
(defn render [{:keys [theta style] :as world-state}]
(->
ctx
(fill-style :black)
(fill-rect screen-area)
(save)
(translate 400 300))
(dotimes [i steps]
(let [offset (* i angle)
x (* 240 (Math/sin (+ theta offset)))
y (* 240 (Math/sin (- theta offset)))
sz (remap (Math/sin (+ theta (* offset 2))) -1 1 30 75)]
((draw-func style) ctx i {:x x :y y :rw (* sz 1.5) :rh sz})))
(restore ctx))
(-> canvas (css :cursor "pointer") (show))
(big-bang
:tick-rate 50
:event-target canvas
:initial-state initial-state
:on-tick update-state
:on-mousedown toggle-style
:to-draw render)
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