configurable hold-last-look

example/sACN Explorer/multiverseview.ui

@@ -70,6 +70,7 @@
      <string>sACN</string>
     </property>
     <addaction name="actionDiscovery"/>
+    <addaction name="actionHold_Last_Look"/>
    </widget>
    <addaction name="menuNetwork"/>
    <addaction name="menuEPI_19"/>
@@ -226,6 +227,23 @@
     <string>Ctrl+D</string>
    </property>
   </action>
+  <action name="actionHold_Last_Look">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="checked">
+    <bool>true</bool>
+   </property>
+   <property name="enabled">
+    <bool>false</bool>
+   </property>
+   <property name="text">
+    <string>Hold Last Look</string>
+   </property>
+   <property name="toolTip">
+    <string>Retain at least 1 inacitve source.</string>
+   </property>
+  </action>
  </widget>
  <resources/>
  <connections/>

protocol/sacn/arbitratinguniverse.cpp

@@ -32,6 +32,7 @@ namespace sACN {
 ArbitratingUniverse::ArbitratingUniverse()
       : sACN::Universe()
       , expectedUniverse(0)
+      , HoldLastLook(true)
 {
 }
 
@@ -44,6 +45,26 @@ ArbitratingUniverse::~ArbitratingUniverse()
 }
 
 
+/**
+ * @brief ArbitratingUniverse::setHoldLastLook
+ * @param state
+ */
+void ArbitratingUniverse::setHoldLastLook(const bool state)
+{
+  HoldLastLook = state;
+}
+
+
+/**
+ * @brief ArbitratingUniverse::getHoldLastLook
+ * @return
+ */
+bool ArbitratingUniverse::getHoldLastLook() const
+{
+  return HoldLastLook;
+}
+
+
 const std::vector<DATA::data_header> ArbitratingUniverse::sources() const
 {
   std::vector<DATA::data_header> keys;
@@ -246,8 +267,8 @@ std::shared_ptr<Universe> ArbitratingUniverse::dominant_()
     {
       auto universe = it->second;
 
-      if (!ret)
+      if (!ret && HoldLastLook)
-        { // anything is better than nothing!
+        { // anything is better than nothing
           ++it;
           ret = universe;
           continue;

protocol/sacn/arbitratinguniverse.h

@@ -61,6 +61,9 @@ public:
 
     uint16_t expectedUniverse; ///< Expected universe number
 
+    void setHoldLastLook(const bool);
+    bool getHoldLastLook() const;
+
     // Source universes:
     void deleteSourceUniverse(const DATA::data_header&);
     void dataChangedNotifier(DMX::Universe* universe);
@@ -91,6 +94,7 @@ public:
 private:
     std::unordered_map<DATA::data_header, std::shared_ptr<Universe>> sources_;
     std::vector<std::function<void()>> cb_sourceListChange;  //!< list of calback functions
+    bool HoldLastLook;
 
     std::shared_ptr<Universe> dominant_();
     bool hasSourceUniverse(const DATA::data_header&) const;

protocol/sacn/receiver.cpp

@@ -36,6 +36,7 @@ namespace sACN {
  */
 Receiver::Receiver(UUID::uuid cid)
   : Component(cid)
+  , HoldLastLook(true)
 {
   fctn_ = "OpenLCP sACN Receiver";
 
@@ -56,6 +57,18 @@ Receiver::~Receiver()
 }
 
 
+/**
+ * @brief Receiver::setHoldLastLook
+ * @param state
+ */
+void Receiver::setHoldLastLook(const bool state)
+{
+  HoldLastLook = state;
+  for (const auto & [_, universe] : universes_)
+    universe->setHoldLastLook(state);
+}
+
+
 /**
  * @brief Receiver::subscribe
  * @param num
@@ -66,6 +79,7 @@ void Receiver::subscribe(const uint16_t num)
     return;
   universes_.emplace(num, std::make_shared<ArbitratingUniverse>());
   universes_.at(num)->expectedUniverse = num;
+  universes_.at(num)->setHoldLastLook(HoldLastLook);
 }
 
 
@@ -222,7 +236,11 @@ void Receiver::dataFrameHandler(ACN::PDU::Message<DATA::Pdu> frame) {
   /// > Any property values in an E1.31 Data Packet containing this bit
   /// > shall be ignored.
   if (source->options.stream_terminated)
-    return universes_[source->universe]->deleteSourceUniverse(*source);
+    {
+      auto universe = universes_.at(source->universe);
+      if (universe->sources().size() > 1 || !HoldLastLook)
+        return universes_[source->universe]->deleteSourceUniverse(*source);
+    }
 
   /// > \cite sACN 6.2.4.1 Synchronization Address Usage in an E1.31 Data Packet
   /// >

protocol/sacn/receiver.h

@@ -69,6 +69,8 @@ public:
   Receiver(UUID::uuid = UUID::uuid());
   ~Receiver();
 
+  void setHoldLastLook(const bool);
+
   virtual void subscribe(const uint16_t);
   virtual void unsubscribe(const uint16_t);
   std::shared_ptr<Universe> universe(const uint16_t);
@@ -98,6 +100,7 @@ protected:
 private:
   std::unordered_map<uint16_t, std::shared_ptr<ArbitratingUniverse>> universes_;
   std::vector<std::function<void()>> discoveryCallbacks_;
+  bool HoldLastLook;
 };
 
 };