matterjs.cljs

(defn sketch
  []
  (let [engine' (.-Engine js/Matter)
        render' (.-Render js/Matter)
        world (.-World js/Matter)
        bodies (.-Bodies js/Matter)
        body (.-Body js/Matter)

        engine (.create engine') 
        add (fn []
              (let [box (.rectangle bodies 140, 0, (+ 10 (rand-int 80)), (+ 10 (rand-int 80)))]
                (.add world (.-world engine) #js[box])
                )
              )
        add-b (fn []
              (let [box (.circle bodies 140, 0, (+ 10 (rand-int 40)), (+ 10 (rand-int 40)))]
                (.add world (.-world engine) #js[box])
                )
              )
        ]
    (r/create-class
      {:component-did-mount
                       (fn [this]
                         (let [render (.create render'
                                               #js{
                                                   :element (r/dom-node this)
                                                   :engine  engine,
                                                   :options #js{
                                                                :width      800,
                                                                :height     400,
                                                                :wireframes false
                                                                }
                                                   })
                               box-a (.rectangle bodies 140, 0, 8, 80)
                               circles (keep-indexed
                                         (fn [idx i] (.circle bodies 130, 0, (* idx 2), 1))
                                         (take 3 (range)))
                               ground (.rectangle bodies 400, 380, 810, 60 #js{:isStatic true})
                               ramp (.rectangle bodies 140, 180, 210, 10 #js{:isStatic true})
                               ]
                           (.rotate body ramp (/ (.-PI js/Math)  ))

                           (.add world (.-world engine) (clj->js
                                                          (concat [box-a
                                                                   ground
                                                                   ramp] circles)))
                           (.run engine' engine)
                           (.run render' render)
                           )
                         )
       :reagent-render (fn []
                         [:div

                          [:div
                           [ant/button {:on-click add} "sq"]
                           [ant/button {:on-click add-b} "ball"]]])})))


[:div
 [:h1 "Simple Matter-js example"]
 [h/js-loader
  {:scripts {#(exists? js/Matter) "https://cdnjs.cloudflare.com/ajax/libs/matter-js/0.14.2/matter.min.js"}
   :loading [:div "loading"]
   :loaded  [:div [sketch]]}]

 ]  

here