Improved handling of resetting of the EventQueue::startTick().

include/osgGA/EventQueue

@@ -196,11 +196,13 @@ class OSGGA_EXPORT EventQueue : public osg::Referenced
         void frame(double time);
         
 
-        void setStartTick(osg::Timer_t tick) { _startTick = tick; }
+        void setStartTick(osg::Timer_t tick) { _startTick = tick; clear(); }
         osg::Timer_t getStartTick() const { return _startTick; }
 
         double getTime() const { return osg::Timer::instance()->delta_s(_startTick, osg::Timer::instance()->tick()); }
 
+        /** clear all events from queue. */
+        void clear();
 
         /** convenience method for create an event ready to fill in.  Clones the getCurrentEventState() to produce a up to date event state. */
         GUIEventAdapter* createEvent();

src/osgGA/EventQueue.cpp

@@ -30,6 +30,13 @@ EventQueue::~EventQueue()
 {
 }
 
+void EventQueue::clear()
+{
+    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_eventQueueMutex);
+    _eventQueue.clear();
+}
+
+
 void EventQueue::setEvents(Events& events)
 {
     OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_eventQueueMutex);
@@ -67,22 +74,41 @@ bool EventQueue::takeEvents(Events& events, double cutOffTime)
     OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_eventQueueMutex);
     if (!_eventQueue.empty())
     {
-        bool eventsTaken = false;
-        Events::iterator itr = _eventQueue.begin();
-        for(;
-            itr != _eventQueue.end() && ((*itr)->getTime() <= cutOffTime);
+        // find last event if queue that came in before the cuttof.
+        Events::reverse_iterator ritr = _eventQueue.rbegin();
+        for(; ritr != _eventQueue.rend() && ((*ritr)->getTime() > cutOffTime); ++ritr) {}
+
+        if (ritr==_eventQueue.rend()) return false;
+        
+        for(Events::iterator itr = _eventQueue.begin();
+            itr != ritr.base();
             ++itr)
         {
             events.push_back(*itr);
-            eventsTaken = true;
         }
 
-        if (eventsTaken)
+        // make sure that the events are in ascending time order, and any out of out events
+        // have their time reset to the next valid time after them in the events list.
+        double previousTime = cutOffTime;
+        for(Events::reverse_iterator itr = events.rbegin();
+            itr != events.rend();
+            ++itr)
         {
-            _eventQueue.erase(_eventQueue.begin(), itr);
+            if ((*itr)->getTime() > previousTime)
+            {
+                OSG_NOTICE<<"Reset event time from "<<(*itr)->getTime()<<" to "<<previousTime<<std::endl;
+                (*itr)->setTime(previousTime);
+            }
+            else
+            {
+                previousTime = (*itr)->getTime();
+            }
         }
 
-        return eventsTaken;
+        // remove the events we are taking from the original event queue.
+        _eventQueue.erase(_eventQueue.begin(), ritr.base());
+
+        return true;
     }
     else
     {