clock2.clj

(ns example.wiki.clock2
  (:use [penumbra.opengl])
  (:require [penumbra.app :as app]))

(defn draw-clock [hour minute second]
  (push-matrix
   (scale 0.5 0.5 1)
   (rotate 180 0 0 1)
   (push-matrix
    (rotate (* -30 (rem hour 24)) 0 0 1)
    (color 1 1 1)
    (line-width 5)
    (draw-lines (vertex 0 0) (vertex 0 -0.5)))
   (push-matrix
    (rotate (* -6 (rem minute 60)) 0 0 1)
    (color 1 1 1)
    (line-width 2)
    (draw-lines (vertex 0 0) (vertex 0 -1)))
   (push-matrix
    (rotate (* -6 (rem second 60)) 0 0 1)
    (color 1 0 0)
    (line-width 1)
    (draw-lines (vertex 0 0) (vertex 0 -1)))))

(defn init [state]
  (app/vsync! true)
  state)

(defn reshape [[x y w h] state]
  (let [aspect (/ (float w) h)
        height (if (> 1 aspect) (/ 1.0 aspect) 1)
        aspect (max 1 aspect)]
    (ortho-view (- aspect) aspect (- height) height -1 1)
    state))

(defn update [[delta time] state]
  (assoc state
    :hour (+ (:hour state) (/ delta 3600))
    :minute (+ (:minute state) (/ delta 60))
    :second (+ (:second state) delta)))

(defn display [[delta time] state]
  (draw-clock (:hour state) (:minute state) (:second state))
  (app/repaint!))

(app/start
  {:display display, :reshape reshape, :update update, :init init}
  {:hour 0 :minute 0 :second 0})