Unsubscribe index of ID, not ID itself

Author: JeffreyATW

src/utils/game-loop.js

@@ -22,6 +22,6 @@ export default class GameLoop {
     return this.subscribers.push(callback);
   }
   unsubscribe(id) {
-    this.subscribers.splice((id - 1), 1);
+    this.subscribers.splice(this.subscribers.indexOf(id), 1);
   }
 }