The libgdx Simple Game Demo in Clojure

Hello world! As a first post, I'd like to share my Clojure implementation of the simple game demo found here:
https://github.com/libgdx/libgdx/wiki/A-simple-game

I'm using Nightcode as my editor (https://github.com/oakes/Nightcode) and it gave me a nice template where to start. I'm not going through all the set up and directory structures of the program here, using nightcode makes it all very easy. The only thing I changed for the launcher code (desktop_launcher.clj) was the resolution of the program.

So without any further blaa blaa, here's the main code (for now, I'll paste it without fancy formatting. Have to check what SyntaxHighlighter has to offer later). I left out the sounds though, because I didn't feel like registering to the page from where I would have had to download them...

(ns com.demo-game.core
  (:import [com.badlogic.gdx Game Gdx Graphics Screen Input$Keys]
           [com.badlogic.gdx.graphics GL10 Color Texture OrthographicCamera]
           [com.badlogic.gdx.graphics.g2d BitmapFont SpriteBatch]
           [com.badlogic.gdx.math Rectangle Vector3 MathUtils]
           [com.badlogic.gdx.scenes.scene2d Stage]
           [com.badlogic.gdx.scenes.scene2d.ui Label Label$LabelStyle]
           [com.badlogic.gdx.utils Array TimeUtils]))

(declare ^Stage stage)

(def asset_path "../android/assets/")

(def droplet-img nil)
(def bucket-img nil)
(def ortocamera nil)
(def batch nil)
(def bucket nil)
(def droplet nil)
(def raindrops (Array.))
(def last-drop nil)

(defn spawn-raindrop []
  (let [raindrop (Rectangle.)]
    (set! (. raindrop x) (.nextInt MathUtils/random (- 800 64)))
    (set! (. raindrop y) 480)
    (set! (. raindrop width) 64)
    (set! (. raindrop height) 64)
    (.add raindrops raindrop)
    (def last-drop (TimeUtils/nanoTime))))

(def main-screen
  (proxy [Screen] []
    (show [] )
    (render [delta]
      (.glClearColor (Gdx/gl) 0 0 0.2 1)
      (.glClear (Gdx/gl) GL10/GL_COLOR_BUFFER_BIT)
      
      (if (> (- (TimeUtils/nanoTime) last-drop) 1000000000)
        (spawn-raindrop))
      
      (if (.isKeyPressed Gdx/input Input$Keys/LEFT)
        (set! (. bucket x)
              (- (. bucket x)(* 200 (.getDeltaTime Gdx/graphics)))))
      (if (.isKeyPressed Gdx/input Input$Keys/RIGHT)
        (set! (. bucket x)
              (+ (. bucket x) (* 200 (.getDeltaTime Gdx/graphics)))))  
      
      (if (.isTouched Gdx/input)
        (let [touch-pos (Vector3.)]
          ; convert the touch coordinates (from input) into the
          ; coordinate system of the camera
          (.set touch-pos (.getX Gdx/input) (.getY Gdx/input) 0)
          (.unproject ortocamera touch-pos)
          (set! (. bucket x) (- (. touch-pos x) (/ 64 2)))))
      
      (let [iter (.iterator raindrops)]
        (while (.hasNext iter)
          (let [rdrop (.next iter)]
            (set! (. rdrop y)
                  (- (. rdrop y) (* 200 (.getDeltaTime Gdx/graphics))))
            (if (< (+ (. rdrop y) 64) 0)
              (.remove iter))
            (if (.overlaps rdrop bucket)
              (.remove iter)))))
      
      (if (< (. bucket x) 0)
        (set! (. bucket x) 0))
      (if (> (. bucket x) (- 800 64))
        (set! (. bucket x) (- 800 64)))
      
      (.update ortocamera)
      (.setProjectionMatrix batch (. ortocamera combined))
      (.begin batch)
      (.draw batch bucket-img (. bucket x) (. bucket y))
      
      (doseq [rdrop (seq raindrops)]
        (.draw batch droplet-img (. rdrop x) (. rdrop y)))
      (.end batch))
    
    (dispose[]
      (.dispose droplet-img)
      (.dispose bucket-img)
      (.dispose batch))
    (hide [])
    (pause [])
    (resize [w h])
    (resume [])))


(gen-class
  :name com.demo-game.core.Game
  :extends com.badlogic.gdx.Game)

(defn -resize [this w h]
  (println "resized to" w "x" h))

(defn -create [this]
  (.setScreen this main-screen)
  (def droplet-img
    (Texture. (.internal (Gdx/files) (str asset_path "droplet.png"))))
  (def bucket-img
    (Texture. (.internal (Gdx/files) (str asset_path "bucket.png"))))
  (def ortocamera (OrthographicCamera.))
  (.setToOrtho ortocamera false 800 480)
  (def batch (SpriteBatch.))
  (def bucket (Rectangle.))
  (set! (. bucket x) (- (/ 800 2) (/ 64 2)))
  (set! (. bucket y) 20)
  (set! (. bucket width) 64)
  (set! (. bucket height) 64)
  (spawn-raindrop))