Added first step to adding pruning of expired image requests.

include/osgDB/ImagePager

@@ -21,6 +21,7 @@
 #include <osg/FrameStamp>
 
 #include <OpenThreads/Mutex>
+#include <OpenThreads/Atomic>
 
 #include <osgDB/ReaderWriter>
 #include <osgDB/Options>
@@ -87,6 +88,14 @@ class OSGDB_EXPORT ImagePager : public osg::NodeVisitor::ImageRequestHandler
         /** Merge the changes to the scene graph. */
         virtual void updateSceneGraph(const osg::FrameStamp &frameStamp);
 
+        /** Signal the image thread that the update, cull and draw has begun for a new frame.
+          * Note, this is called by the application so that the image pager can go to sleep while the CPU is busy on the main rendering threads. */
+        virtual void signalBeginFrame(const osg::FrameStamp* framestamp);
+
+        /** Signal the image thread that the update, cull and draw dispatch has completed.
+          * Note, this is called by the application so that the image pager can go to wake back up now the main rendering threads are iddle waiting for the next frame.*/
+        virtual void signalEndFrame();
+
         int cancel();
 
     protected:
@@ -105,6 +114,7 @@ class OSGDB_EXPORT ImagePager : public osg::NodeVisitor::ImageRequestHandler
                 _timeToMergeBy(0.0),
                 _attachmentIndex(-1) {}
 
+            unsigned int                        _frameNumber;
             double                              _timeToMergeBy;
             std::string                         _fileName;
             osg::ref_ptr<Options> _loadOptions;
@@ -160,6 +170,9 @@ class OSGDB_EXPORT ImagePager : public osg::NodeVisitor::ImageRequestHandler
         bool                        _done;
         bool                        _databasePagerThreadPaused;
 
+        OpenThreads::Atomic         _frameNumber;
+
+        OpenThreads::Mutex          _ir_mutex;
         osg::ref_ptr<ReadQueue>     _readQueue;
 
         typedef std::vector< osg::ref_ptr<ImageThread> > ImageThreads;

src/osgDB/ImagePager.cpp

@@ -78,19 +78,14 @@ void ImagePager::ReadQueue::clear()
     updateBlock();
 }
 
-void ImagePager::ReadQueue::add(ImagePager::ImageRequest* databaseRequest)
+void ImagePager::ReadQueue::add(ImagePager::ImageRequest* imageRequest)
 {
-    // tempo hack to avoid the ImagePager accumulating requests when it can keep up,
-    // note this will mean that only one ImageSequence can be properly managed at one time,
-    // this hack will be removed once a better system for managing expiry of requests is introduced.
-    // clear();
-
     OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_requestMutex);
     
-    _requestList.push_back(databaseRequest);
+    _requestList.push_back(imageRequest);
-    databaseRequest->_requestQueue = this;
+    imageRequest->_requestQueue = this;
 
-    OSG_INFO<<"ImagePager::ReadQueue::add("<<databaseRequest->_fileName<<"), size()="<<_requestList.size()<<std::endl;
+    OSG_INFO<<"ImagePager::ReadQueue::add("<<imageRequest->_fileName<<"), size()="<<_requestList.size()<<std::endl;
 
     updateBlock();
 }
@@ -177,6 +172,21 @@ int ImagePager::ImageThread::cancel()
     return result;
 }
 
+void ImagePager::signalBeginFrame(const osg::FrameStamp* framestamp)
+{
+    if (framestamp)
+    {
+        //OSG_INFO << "signalBeginFrame "<<framestamp->getFrameNumber()<<">>>>>>>>>>>>>>>>"<<std::endl;
+        _frameNumber.exchange(framestamp->getFrameNumber());
+
+    } //else OSG_INFO << "signalBeginFrame >>>>>>>>>>>>>>>>"<<std::endl;
+}
+
+void ImagePager::signalEndFrame()
+{
+}
+
+
 void ImagePager::ImageThread::run()
 {
     OSG_INFO<<"ImagePager::ImageThread::run() "<<this<<std::endl;
@@ -269,9 +279,9 @@ ImagePager::ImagePager():
     _readQueue = new ReadQueue(this,"Image Queue");
     _completedQueue = new RequestQueue;
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 1"));
-#if 1
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 2"));
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 3"));
+#if 0
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 4"));
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 5"));
     _imageThreads.push_back(new ImageThread(this, ImageThread::HANDLE_ALL_REQUESTS, "Image Thread 6"));

src/osgViewer/ViewerBase.cpp

@@ -759,10 +759,10 @@ void ViewerBase::renderingTraversals()
     {
         Scene* scene = *sitr;
         osgDB::DatabasePager* dp = scene ? scene->getDatabasePager() : 0;
-        if (dp)
+        if (dp) dp->signalBeginFrame(frameStamp);
-        {
+
-            dp->signalBeginFrame(frameStamp);
+        osgDB::ImagePager* ip = scene ? scene->getImagePager() : 0;
-        }
+        if (ip) ip->signalBeginFrame(frameStamp);
 
         if (scene->getSceneData())
         {
@@ -841,10 +841,10 @@ void ViewerBase::renderingTraversals()
     {
         Scene* scene = *sitr;
         osgDB::DatabasePager* dp = scene ? scene->getDatabasePager() : 0;
-        if (dp)
+        if (dp) dp->signalEndFrame();
-        {
+
-            dp->signalEndFrame();
+        osgDB::ImagePager* ip = scene ? scene->getImagePager() : 0;
-        }
+        if (ip) ip->signalEndFrame();
     }
 
     // wait till the dynamic draw is complete.