From 282fa847895f15296005eee6b8b34260eb4e86a9 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 4 Jun 2008 16:46:14 +0000
Subject: [PATCH] Added support for optionally calling releaseContext at the
 end of each renderinTraversals() to help with cases where uses are driving
 multiple contexts from mulitple viewers in a single threaded frame loop.

---
 include/osgViewer/ViewerBase      | 15 ++++++++++++++-
 src/osgViewer/CompositeViewer.cpp |  2 ++
 src/osgViewer/Viewer.cpp          |  2 ++
 src/osgViewer/ViewerBase.cpp      | 10 ++++++++--
 4 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/include/osgViewer/ViewerBase b/include/osgViewer/ViewerBase
index d9cace115..e042de489 100644
--- a/include/osgViewer/ViewerBase
+++ b/include/osgViewer/ViewerBase
@@ -140,6 +140,18 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
         bool getQuitEventSetsDone() const { return _quitEventSetsDone; }
 
 
+        /** Hint to tell the renderingTraversals() method whether to call relaseContext() on the last
+          * context that was made current by the thread calling renderingTraverals().  Note, when 
+          * running multi-threaded viewer no threads will be made current or release current.
+          * Setting this hint to false can enable the frame loop to be lazy about calling makeCurrent
+          * and releaseContext on each new frame, helping performance.  However, if you frame loop
+          * is managing multiple graphics context all from the main frame thread then this hint must
+          * be left on, otherwise the wrong context could be left active, introducing errors in rendering.*/
+        void setReleaseContextAtEndOfFrameHint(bool hint) { _releaseContextAtEndOfFrameHint = hint; }
+        
+        /** Hint to tell the renderingTraversals() method whether to call relaseContext().*/
+        bool getReleaseContextAtEndOfFrameHint() const { return _releaseContextAtEndOfFrameHint; }
+
 
         /** Set the UpdateVisitor. */
         void setUpdateVisitor(osgUtil::UpdateVisitor* updateVisitor) { _updateVisitor = updateVisitor; }
@@ -225,7 +237,7 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
 
         /** Get the keyboard and mouse usage of this viewer.*/
         virtual void getUsage(osg::ApplicationUsage& usage) const = 0;
-
+        
     protected:
     
         inline void makeCurrent(osg::GraphicsContext* gc)
@@ -255,6 +267,7 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
         bool                                        _done;
         int                                         _keyEventSetsDone;
         bool                                        _quitEventSetsDone;
+        bool                                        _releaseContextAtEndOfFrameHint;
         
         ThreadingModel                              _threadingModel;
         bool                                        _threadsRunning;
diff --git a/src/osgViewer/CompositeViewer.cpp b/src/osgViewer/CompositeViewer.cpp
index c4fd6ee82..a3e3e099f 100644
--- a/src/osgViewer/CompositeViewer.cpp
+++ b/src/osgViewer/CompositeViewer.cpp
@@ -184,6 +184,8 @@ int CompositeViewer::run()
         }
     }
         
+    setReleaseContextAtEndOfFrameHint(false);
+
     return ViewerBase::run();
 }
 
diff --git a/src/osgViewer/Viewer.cpp b/src/osgViewer/Viewer.cpp
index a5dda88bc..6872f43bd 100644
--- a/src/osgViewer/Viewer.cpp
+++ b/src/osgViewer/Viewer.cpp
@@ -316,6 +316,8 @@ int Viewer::run()
     {
         setCameraManipulator(new osgGA::TrackballManipulator());
     }
+    
+    setReleaseContextAtEndOfFrameHint(false);
             
     return ViewerBase::run();
 }
diff --git a/src/osgViewer/ViewerBase.cpp b/src/osgViewer/ViewerBase.cpp
index dfee2dc8d..8a8e98676 100644
--- a/src/osgViewer/ViewerBase.cpp
+++ b/src/osgViewer/ViewerBase.cpp
@@ -43,6 +43,7 @@ ViewerBase::ViewerBase():
     _done = false;
     _keyEventSetsDone = osgGA::GUIEventAdapter::KEY_Escape;
     _quitEventSetsDone = true;
+    _releaseContextAtEndOfFrameHint = true;
     _threadingModel = AutomaticSelection;
     _threadsRunning = false;
     _endBarrierPosition = AfterSwapBuffers;
@@ -55,6 +56,7 @@ ViewerBase::ViewerBase(const ViewerBase& base):
     _done = false;
     _keyEventSetsDone = osgGA::GUIEventAdapter::KEY_Escape;
     _quitEventSetsDone = true;
+    _releaseContextAtEndOfFrameHint = true;
     _threadingModel = AutomaticSelection;
     _threadsRunning = false;
     _endBarrierPosition = AfterSwapBuffers;
@@ -721,8 +723,12 @@ void ViewerBase::renderingTraversals()
         _endDynamicDrawBlock->block();
         // osg::notify(osg::NOTICE)<<"Time waiting "<<osg::Timer::instance()->delta_m(startTick, osg::Timer::instance()->tick())<<std::endl;;
     }
-
-
+    
+    if (_releaseContextAtEndOfFrameHint)
+    {
+        osg::notify(osg::NOTICE)<<"Doing release context"<<std::endl;
+        releaseContext();
+    }
 
     if (getStats() && getStats()->collectStats("update"))
     {