Stop TTS from playing over itself.

Simple blocking of the SGSubsystem until the current
TTS sample has finished playing, allowing a 0.5s
gap between transmissions.  Good radio comms!

src/Sound/flitevoice.cxx

@@ -33,7 +33,7 @@ using std::string;
 #include "VoiceSynthesizer.hxx"
 
 FGFLITEVoice::FGFLITEVoice(FGVoiceMgr * mgr, const SGPropertyNode_ptr node, const char * sampleGroupRefName)
-    : FGVoice(mgr), _synthesizer( NULL)
+    : FGVoice(mgr), _synthesizer( NULL), _seconds_to_run(0.0)
 {
 
   _sampleName = node->getStringValue("desc", node->getPath().c_str());
@@ -68,14 +68,21 @@ void FGFLITEVoice::speak(const string & msg)
   }
 }
 
-void FGFLITEVoice::update()
+void FGFLITEVoice::update(double dt)
 {
+  _seconds_to_run -= dt;
+
+  if (_seconds_to_run < 0.0) {
     SGSharedPtr<SGSoundSample> sample = _sampleQueue.pop();
     if (sample.valid()) {
       _sgr->remove(_sampleName);
       _sgr->add(sample, _sampleName);
       _sgr->resume();
       _sgr->play(_sampleName, false);
-  }
-}
 
+      // Don't play any further TTS until we've finished playing this sample,
+      // allowing 500ms for a gap between transmissions.  Good radio comms!
+      _seconds_to_run = 0.5 +  ((float) sample->get_no_samples()) / ((float) sample->get_frequency());
+  }
+  }
+}

src/Sound/flitevoice.hxx

@@ -35,7 +35,7 @@ public:
   FGFLITEVoice(FGVoiceMgr *, const SGPropertyNode_ptr, const char * sampleGroupRefName = "flite-voice");
   virtual ~FGFLITEVoice();
   virtual void speak(const std::string & msg);
-  virtual void update();
+  virtual void update(double dt);
 
 private:
   FGFLITEVoice(const FGFLITEVoice & other);
@@ -45,6 +45,7 @@ private:
   VoiceSynthesizer * _synthesizer;
   SGLockedQueue<SGSharedPtr<SGSoundSample> > _sampleQueue;
   std::string _sampleName;
+  double _seconds_to_run;
 };
 
 #endif // _FLITEVOICE_HXX

src/Sound/voice.cxx

@@ -43,7 +43,7 @@ public:
   FGFestivalVoice(FGVoiceMgr *, const SGPropertyNode_ptr);
   virtual ~FGFestivalVoice();
   virtual void speak( const string & msg );
-  virtual void update();
+  virtual void update(double);
   void setVolume(double);
   void setPitch(double);
   void setSpeed(double);
@@ -129,14 +129,14 @@ void FGVoiceMgr::shutdown()
 }
 
 
-void FGVoiceMgr::update(double)
+void FGVoiceMgr::update(double dt)
 {
 	if (!_enabled)
 		return;
 
 	_paused = !_pausedNode->getBoolValue();
 	for (unsigned int i = 0; i < _voices.size(); i++) {
-		_voices[i]->update();
+		_voices[i]->update(dt);
 #if !defined(ENABLE_THREADS)
 		_voices[i]->speak();
 #endif
@@ -235,7 +235,7 @@ void FGFestivalVoice::speak( const string & msg )
 }
 
 
-void FGFestivalVoice::update(void)
+void FGFestivalVoice::update(double dt)
 {
 		double d;
 		d = _volumeNode->getDoubleValue();
@@ -333,5 +333,3 @@ void FGVoiceMgr::FGVoice::valueChanged(SGPropertyNode *node)
 
 	pushMessage(m);
 }
-
-

src/Sound/voice.hxx

@@ -99,7 +99,7 @@ public:
   FGVoice(FGVoiceMgr * mgr ) : _mgr(mgr) {}
   virtual ~FGVoice() {}
   virtual void speak( const std::string & msg ) = 0;
-  virtual void update() = 0;
+  virtual void update(double dt) = 0;
   void pushMessage( const std::string & m);
   bool speak();