jMonkeyEngine3 from Clojure

Written by:

Robert McIntyre

[TABLE-OF-CONTENTS]

Here are the jMonkeyEngine "Hello" programs translated to clojure.

1 Hello Simple App

Here is the hello world example for jme3 in clojure. It's a more or less direct translation from the java source here.

Of note is the fact that since we don't have access to the AssetManager via extending SimpleApplication, we have to build one ourselves.

(ns hello.hello-simple-app
  (:use cortex.world)
  (:import com.jme3.math.Vector3f)
  (:import com.jme3.material.Material)
  (:import com.jme3.scene.Geometry)
  (:import com.jme3.math.ColorRGBA)
  (:import com.jme3.app.SimpleApplication)
  (:import com.jme3.scene.shape.Box))

(def cube (Box. Vector3f/ZERO 1 1 1))

(def geom (Geometry. "Box" cube))

(def mat (Material. (asset-manager) "Common/MatDefs/Misc/Unshaded.j3md"))

(.setColor mat "Color" ColorRGBA/Blue)

(.setMaterial geom mat)

(defn simple-app []
  (doto
      (proxy [SimpleApplication] []
        (simpleInitApp
         []
         ;; Don't take control of the mouse
         (org.lwjgl.input.Mouse/setGrabbed false)
         (.attachChild (.getRootNode this) geom)))
    ;; don't show a menu to change options.
    (.setShowSettings false)
    (.setPauseOnLostFocus false)
    (.setSettings *app-settings*)))

Running this program will begin a new jMonkeyEngine game which displays a single blue cube.

(.start (hello.hello-simple-app/simple-app))

Figure 1: the simplest JME game.

2 Simpler HelloSimpleApp

(ns hello.hello-simpler-app
  (:use cortex.world)
  (:use cortex.util)
  (:import com.jme3.math.ColorRGBA)
  (:import com.jme3.scene.Node))

(defn simpler-world
  "The jMonkeyEngine3 Hello World program.  Displays a blue 3D cube in
   a basic 3D world."
  []
  (world (doto (Node.)
           (.attachChild
            (box 1 1 1
                 :color ColorRGBA/Blue :physical? false)))
         {} no-op no-op))

More information about the jMonkeyEngine3 hello world program can be found here.

3 Hello Loop

(ns hello.loop
  (:use cortex.world)
  (:use cortex.util)
  (:import com.jme3.math.ColorRGBA)
  (:import com.jme3.scene.Node))
  
(defn blue-cube []
  (box 1 1 1
       :color ColorRGBA/Blue
       :texture false
       :material "Common/MatDefs/Misc/Unshaded.j3md"
       :name "blue-cube"
       :physical? false))

(defn blue-cube-game []
  (let [cube (blue-cube)
        root (doto (Node.) (.attachChild cube))]
  (world root
         {}
         no-op
         (fn [game tpf]
           (.rotate cube 0.0 (* 2 tpf) 0.0)))))

jMonkeyEngine3 from Clojure

aurellem ☉

1 Hello Simple App

2 Simpler HelloSimpleApp

3 Hello Loop