Limit scene broadcast publications when paused

include/ignition/gazebo/gui/GuiRunner.hh

@@ -74,6 +74,10 @@ class IGNITION_GAZEBO_VISIBLE GuiRunner : public QObject
 
   /// \brief Latest update info
   private: UpdateInfo updateInfo;
+
+  /// \brief Update the plugins.
+  /// \todo(anyone) Move to a private data class.
+  private: void UpdatePlugins();
 };
 }
 }

src/gui/GuiRunner.cc

@@ -30,6 +30,15 @@
 using namespace ignition;
 using namespace gazebo;
 
+/// \brief Flag used to end the gUpdateThread.
+static bool gRunning = false;
+
+/// \brief Mutex to protect the plugin update.
+static std::mutex gUpdateMutex;
+
+/// \brief The plugin update thread..
+static std::thread gUpdateThread;
+
 /////////////////////////////////////////////////
 GuiRunner::GuiRunner(const std::string &_worldName)
 {
@@ -51,10 +60,32 @@ GuiRunner::GuiRunner(const std::string &_worldName)
          << std::endl;
 
   this->RequestState();
+
+  // Periodically update the plugins
+  // \todo(anyone) Pimplize GuiRunner and move these global variables to the
+  // private class.
+  gRunning = true;
+  gUpdateThread = std::thread([&]()
+  {
+    while (gRunning)
+    {
+      {
+        std::lock_guard<std::mutex> lock(gUpdateMutex);
+        this->UpdatePlugins();
+      }
+      // This is roughly a 30Hz update rate.
+      std::this_thread::sleep_for(std::chrono::milliseconds(33));
+    }
+  });
 }
 
 /////////////////////////////////////////////////
-GuiRunner::~GuiRunner() = default;
+GuiRunner::~GuiRunner()
+{
+  gRunning = false;
+  if (gUpdateThread.joinable())
+    gUpdateThread.join();
+}
 
 /////////////////////////////////////////////////
 void GuiRunner::RequestState()
@@ -108,16 +139,22 @@ void GuiRunner::OnState(const msgs::SerializedStepMap &_msg)
   IGN_PROFILE_THREAD_NAME("GuiRunner::OnState");
   IGN_PROFILE("GuiRunner::Update");
 
+  std::lock_guard<std::mutex> lock(gUpdateMutex);
   this->ecm.SetState(_msg.state());
 
   // Update all plugins
   this->updateInfo = convert<UpdateInfo>(_msg.stats());
+  this->UpdatePlugins();
+  this->ecm.ClearNewlyCreatedEntities();
+  this->ecm.ProcessRemoveEntityRequests();
+}
+
+/////////////////////////////////////////////////
+void GuiRunner::UpdatePlugins()
+{
   auto plugins = gui::App()->findChildren<GuiSystem *>();
   for (auto plugin : plugins)
   {
     plugin->Update(this->updateInfo, this->ecm);
   }
-  this->ecm.ClearNewlyCreatedEntities();
-  this->ecm.ProcessRemoveEntityRequests();
 }
-

src/systems/scene_broadcaster/SceneBroadcaster.cc

@@ -198,6 +198,9 @@ class ignition::gazebo::systems::SceneBroadcasterPrivate
 
   /// \brief A list of async state requests
   public: std::unordered_set<std::string> stateRequests;
+
+  /// \brief Stores change event information during PreUpdate.
+  public: bool changeEvent{false};
 };
 
 //////////////////////////////////////////////////
@@ -239,6 +242,16 @@ void SceneBroadcaster::Configure(
   }
 }
 
+//////////////////////////////////////////////////
+void SceneBroadcaster::PreUpdate(const UpdateInfo &_info,
+    EntityComponentManager &_ecm)
+{
+  bool jumpBackInTime = _info.dt < std::chrono::steady_clock::duration::zero();
+  this->dataPtr->changeEvent =  _ecm.HasEntitiesMarkedForRemoval() ||
+        _ecm.HasNewEntities() || _ecm.HasOneTimeComponentChanges() ||
+        jumpBackInTime;
+}
+
 //////////////////////////////////////////////////
 void SceneBroadcaster::PostUpdate(const UpdateInfo &_info,
     const EntityComponentManager &_manager)
@@ -272,14 +285,15 @@ void SceneBroadcaster::PostUpdate(const UpdateInfo &_info,
   // Throttle here instead of using transport::AdvertiseMessageOptions so that
   // we can skip the ECM serialization
   bool jumpBackInTime = _info.dt < std::chrono::steady_clock::duration::zero();
+  this->dataPtr->changeEvent =  this->dataPtr->changeEvent ||
+    _manager.HasEntitiesMarkedForRemoval() ||
+    _manager.HasNewEntities() || _manager.HasOneTimeComponentChanges() ||
+    jumpBackInTime;
   auto now = std::chrono::system_clock::now();
-  bool changeEvent = _manager.HasEntitiesMarkedForRemoval() ||
-        _manager.HasNewEntities() || _manager.HasOneTimeComponentChanges() ||
-        jumpBackInTime;
-  bool itsPubTime = now - this->dataPtr->lastStatePubTime >
-       this->dataPtr->statePublishPeriod;
+  bool itsPubTime = !_info.paused && (now - this->dataPtr->lastStatePubTime >
+       this->dataPtr->statePublishPeriod);
   auto shouldPublish = this->dataPtr->statePub.HasConnections() &&
-       (changeEvent || itsPubTime);
+       (this->dataPtr->changeEvent || itsPubTime);
 
   if (this->dataPtr->stateServiceRequest || shouldPublish)
   {
@@ -289,7 +303,7 @@ void SceneBroadcaster::PostUpdate(const UpdateInfo &_info,
     set(this->dataPtr->stepMsg.mutable_stats(), _info);
 
     // Publish full state if there are change events
-    if (changeEvent || this->dataPtr->stateServiceRequest)
+    if (this->dataPtr->changeEvent || this->dataPtr->stateServiceRequest)
     {
       _manager.State(*this->dataPtr->stepMsg.mutable_state(), {}, {}, true);
     }
@@ -917,6 +931,7 @@ void SceneBroadcasterPrivate::RemoveFromGraph(const Entity _entity,
 IGNITION_ADD_PLUGIN(SceneBroadcaster,
                     ignition::gazebo::System,
                     SceneBroadcaster::ISystemConfigure,
+                    SceneBroadcaster::ISystemPreUpdate,
                     SceneBroadcaster::ISystemPostUpdate)
 
 // Add plugin alias so that we can refer to the plugin without the version

src/systems/scene_broadcaster/SceneBroadcaster.hh

@@ -41,6 +41,7 @@ namespace systems
   class IGNITION_GAZEBO_VISIBLE SceneBroadcaster:
     public System,
     public ISystemConfigure,
+    public ISystemPreUpdate,
     public ISystemPostUpdate
   {
     /// \brief Constructor
@@ -55,6 +56,12 @@ namespace systems
                            EntityComponentManager &_ecm,
                            EventManager &_eventMgr) final;
 
+    // Documentation inherited
+    public: void PreUpdate(
+                const ignition::gazebo::UpdateInfo &_info,
+                ignition::gazebo::EntityComponentManager &_ecm) override;
+
+    // Documentation inherited
     public: void PostUpdate(const UpdateInfo &_info,
                 const EntityComponentManager &_ecm) final;