gistfile1.clj

; Daniel Shiffman's initial example in his PVector + Processing Tutorial
; re-written in clojure

(ns example1
  (:use [rosado.processing]
        [rosado.processing.applet]))

(set! *warn-on-reflection* true)

(def x (atom 100))
(def y (atom 100))
(def xspeed (atom 1))
(def yspeed (atom 3.3))


(defn draw-background
  []
  (no-stroke)
  (fill 255 10)
  (rect 0 0 (width) (height)))

(defn draw-ball
  []
  (stroke 0)
  (fill 175)
  (ellipse @x @y 16 16))

(defn bounced?
  "Checks to see if the ball has crossed any of our bounds"
  [location, bound, current-speed]
  (or (and (> location bound) (> current-speed 0))
      (and (< location 0) (< current-speed 0))))

(defn increment-position-and-speed
  []
  (swap! x + @xspeed)
  (swap! y + @yspeed)
  (if (bounced? @x (width) @xspeed)
    (swap! xspeed * -1))
  (if (bounced? @y (height) @yspeed)
    (swap! yspeed * -1)))


(defn bounce-ball
  "The meat. Draws a ball, increments it's position and speed"
  []
  (draw-background)
  (draw-ball)
  (increment-position-and-speed))


(defn setup
  "The setup. Gets run once."
  []
  (smooth)
  (background 255))

(defn draw
  "Draw loop. Gets called for every frame."
  []
  (bounce-ball))

;; Now we just need to define an applet:
(defapplet example1 :title "An example."
  :setup setup :draw draw :size [200 200])

(run example1)

;; (stop example1)