Kind of boids... but not really

lwjgl-not-boids-core.clj

(ns boids-gl.core
  (:import (org.lwjgl LWJGLException )
           (org.lwjgl.opengl Display DisplayMode GL11))
  (:gen-class))


(defn start []
  (let [ display (DisplayMode. 800 600) ]
    (try 
      (do
        (Display/setDisplayMode display)
        (Display/create))
      (catch  LWJGLException e  
        (do (str "caught exception: " (.getMessage e)))
        (System/exit 1)))))

(defn setupOpenGL []
  (GL11/glMatrixMode GL11/GL_PROJECTION)
  (GL11/glLoadIdentity)
  (GL11/glOrtho 0 800 0 600 1 -1)
  (GL11/glMatrixMode GL11/GL_MODELVIEW)
 )



(defn magnitute 
  [x y]
  (Math/sqrt (+ (* x x) (* y y))))



(defrecord Boid [ x y dx dy ])

(defn update-position
  [b]
  (let [ newx (+ (:x b) (:dx b))
         newy (+ (:y b) (:dy b))
         delta-x (if (or (> newx 800) (< newx 0) )  (* -1 (:dx b))  (:dx b) )
         delta-y (if (or (> newy 400) (< newy 0) )  (* -1 (:dy b))  (:dy b) )  ]
        (Boid. newx newy delta-x delta-y)))


(defn draw-boid
  [ a-boid ]
    (GL11/glColor3f 0.5 0.5 1.0)
    (let [ x (:x a-boid) 
           y (:y a-boid)
           
           unitize (fn [ xx yy ] 
                     (let [m (magnitute xx yy) 
                           nx  (if (< 0 xx) (* xx (/ 1 m)) 0)
                           ny  (if (< 0 yy) (* yy (/ 1 m)) 1) ]
                       [ nx  ny ]))

          perpindicular (fn [ x y ]
                          [(* y -1) x ])

          [ dx dy  ] (unitize (:dx a-boid) (:dy a-boid))

          [ px py  ] (perpindicular  dx dy ) ]
          
    (GL11/glBegin GL11/GL_TRIANGLES)
       (GL11/glVertex2f (+ x (* dx 10)) (+ y (* dy 10)))
       (GL11/glVertex2f (+ x (* px 5)) (+ y (* py 5)))
       (GL11/glVertex2f (- x (* px 5)) (- y (* py 5)))
    (GL11/glEnd)
    ))


(defn draw-boids [boid-agents]
  (doseq [boid boid-agents]
    (draw-boid @boid)))


(defn mainloop [ some-boids ]
  (when-not (Display/isCloseRequested)
    (GL11/glClear (bit-or GL11/GL_COLOR_BUFFER_BIT GL11/GL_DEPTH_BUFFER_BIT))
    
    (draw-boids some-boids)
    (doseq [ agent-boid some-boids]
      (send-off agent-boid update-position ))
    (Display/update)
    (recur some-boids)))


(defn -main
  [& args]

  (println "Test" )
  (start)
  (setupOpenGL)
  (let [  the-boids (take 50
                        (repeatedly 
                         (fn[] (agent (Boid. (rand-int 800) (rand-int 600) 1 1 )))))]

    (mainloop the-boids))
  (Display/destroy)
  )

project.clj

(defproject boids-gl "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.6.0"]
                 [org.lwjgl.lwjgl/lwjgl "2.9.1"]
                 [org.lwjgl.lwjgl/lwjgl-platform "2.9.1"
                  :classifier "natives-osx"
                  ;; LWJGL stores natives in the root of the jar; this
                  ;; :native-prefix will extract them.
                  :native-prefix ""]] 

  :main ^:skip-aot boids-gl.core
  :target-path "target/%s"
  :profiles {:uberjar {:aot :all}})