Add timer

src/play_clj/core.clj

@@ -24,11 +24,13 @@
            [com.badlogic.gdx.physics.box2d ContactListener Joint World]
            [com.badlogic.gdx.scenes.scene2d Actor Stage]
            [com.badlogic.gdx.scenes.scene2d.utils ActorGestureListener Align
-            ChangeListener ClickListener DragListener FocusListener]))
+            ChangeListener ClickListener DragListener FocusListener]
+           [com.badlogic.gdx.utils Timer$Task]))
 
 (load "core_global")
 (load "core_graphics")
 (load "core_listeners")
+(load "core_utils")
 
 (defn ^:private reset-changed!
   "Internal use only"
@@ -38,7 +40,7 @@
 
 (defn defscreen*
   "Internal use only"
-  [{:keys [on-show on-render on-hide on-pause on-resize on-resume]
+  [{:keys [on-show on-render on-hide on-pause on-resize on-resume on-timer]
     :as options}]
   (let [screen (atom {})
         entities (atom [])
@@ -63,6 +65,8 @@
              (swap! screen assoc
                     :total-time 0
                     :update-fn! #(apply swap! screen %1 %2)
+                    :execute-fn! execute-fn!
+                    :on-timer on-timer
                     :ui-listeners (ui-listeners options execute-fn!)
                     :g2dp-listener (contact-listener options execute-fn!))
              (execute-fn! on-show))

src/play_clj/core_utils.clj

@@ -0,0 +1,65 @@
+(in-ns 'play-clj.core)
+
+(defmacro scaling
+  "Returns a static field from [Scaling](http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Scaling.html)
+
+    (scaling :fill)
+    (scaling :fill-x)
+    (scaling :fill-y)
+    (scaling :fit)
+    (scaling :none)
+    (scaling :stretch)
+    (scaling :stretch-x)
+    (scaling :stretch-y)"
+  [k]
+  `~(u/gdx-field :utils :Scaling k))
+
+(defn ^:private task*
+  "Internal use only."
+  [{:keys [execute-fn! on-timer]} id]
+  (proxy [Timer$Task] []
+    (run []
+      (execute-fn! on-timer :id id))))
+
+(defn ^:private timer*
+  "Internal use only."
+  []
+  (some-> (Class/forName "com.badlogic.gdx.utils.Timer")
+          (try (catch Exception _))
+          .newInstance))
+
+(defn ^:private create-and-add-timer!
+  "Internal use only."
+  [{:keys [update-fn!] :as screen} id]
+  (when-let [timer (timer*)]
+    (update-fn! assoc-in [[:timers id] timer])
+    timer))
+
+(defn add-timer!
+  "Returns a [Timer](http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Timer.html)
+that runs the :on-timer function according to the given arguments
+
+    ; wait 2 seconds and run once
+    (add-timer! screen :spawn-enemy 2)
+    ; wait 2 seconds and run forever at 10 second intervals
+    (add-timer! screen :spawn-enemy 2 10)
+    ; wait 2 seconds, run once, and then run 3 more times at 10 second intervals
+    (add-timer! screen :spawn-enemy 2 10 3)"
+  ([screen id delay]
+    (doto (create-and-add-timer! screen id)
+      (.scheduleTask (task* screen id) delay)))
+  ([screen id delay interval]
+    (doto (create-and-add-timer! screen id)
+      (.scheduleTask (task* screen id) delay interval)))
+  ([screen id delay interval repeat]
+    (doto (create-and-add-timer! screen id)
+      (.scheduleTask (task* screen id) delay interval repeat))))
+
+(defn remove-timer!
+  "Stops and removes the timer associated with `id`, returning it or nil if not
+found"
+  [{:keys [update-fn!] :as screen} id]
+  (when-let [timer (get-in screen [:timers id])]
+    (.stop timer)
+    (update-fn! update-in [[:timers] dissoc id])
+    timer))

src/play_clj/utils.clj

@@ -86,20 +86,6 @@
   [& args]
   (apply gdx (add-divider args "$")))
 
-(defmacro scaling
-  "Returns a static field from [Scaling](http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/utils/Scaling.html)
-
-    (scaling :fill)
-    (scaling :fill-x)
-    (scaling :fill-y)
-    (scaling :fit)
-    (scaling :none)
-    (scaling :stretch)
-    (scaling :stretch-x)
-    (scaling :stretch-y)"
-  [k]
-  `~(gdx-field :utils :Scaling k))
-
 ; java interop
 
 (defmacro call!