clojure jogl glDrawElements

(ns glfoo.core
  (:import (javax.swing JFrame)
           (javax.media.opengl.awt GLCanvas)
           (javax.media.opengl GLEventListener GL2 GLAutoDrawable)
           (java.nio ByteBuffer IntBuffer FloatBuffer)))

(defn make-direct-float-buffer
  "Return a direct java.nio.FloatBuffer
elements -- sequence of numbers"
  [elements]
  (let [bytebuf (ByteBuffer/allocateDirect (* (count elements) 4))
        floatbuf (.asFloatBuffer bytebuf)]
    (.put floatbuf (float-array elements))
    (.rewind floatbuf)))

(defn go []
  (let [frame (JFrame. "OpenGL")
        canvas (GLCanvas.)
        verts [-1 1 0 0 -1 0 1 1 0]
        vert-buf (make-direct-float-buffer verts)
        indices (IntBuffer/wrap (int-array [0 1 2]))]
    (.addGLEventListener
     canvas
     (proxy [GLEventListener] []
       (display [#^GLAutoDrawable drawable]
         (doto (.getGL drawable)
           (.glClear (bit-or GL2/GL_COLOR_BUFFER_BIT
                             GL2/GL_DEPTH_BUFFER_BIT))

           ;; (.glBegin GL2/GL_TRIANGLES)
           ;; (.glVertex3fv (float-array (subvec verts 0 3)) 0)
           ;; (.glVertex3fv (float-array (subvec verts 3 6)) 0)
           ;; (.glVertex3fv (float-array (subvec verts 6 9)) 0)
           ;; (.glEnd)

           ;; The previous commented triangle code renders fine,
           ;; but the following renders nothing.
           (.glEnableClientState GL2/GL_VERTEX_ARRAY)
           (.glVertexPointer 3 GL2/GL_FLOAT 0 vert-buf)
           (.glDrawElements GL2/GL_TRIANGLES 3 GL2/GL_UNSIGNED_INT indices)
           (.glDisableClientState GL2/GL_VERTEX_ARRAY)
           ))
       (reshape [#^GLAutoDrawable drawable x y w h]
         (doto (.getGL drawable)
               (.glViewport 0 0 w h)
               (.glMatrixMode GL2/GL_PROJECTION)
               (.glLoadIdentity)
               (.glOrtho -1.5 1.5 -1.5 1.5 -1.5 1.5)
               (.glMatrixMode GL2/GL_MODELVIEW)))))
    (doto frame
      (.add canvas)
      (.setSize 500 500)
      (.setVisible true))))

(comment project.clj contents
  (defproject glfoo "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 "1.5.1"]
                   [org.clojars.toxi/jogl "2.0.0-rc11"]]))