From b0b98d49b82419732dfe7fcfb79031eb30868f19 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Tue, 24 Jan 2012 17:21:14 +0000
Subject: [PATCH] From Paul Martz, Added
 ViewerBase::s/getEndBarrierOperation(..) method to allow user control of how
 viewers are sync'd.

---
 include/osgViewer/ViewerBase | 10 ++++++++++
 src/osgViewer/ViewerBase.cpp |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/osgViewer/ViewerBase b/include/osgViewer/ViewerBase
index 488c64bf5..ac7ab2a75 100644
--- a/include/osgViewer/ViewerBase
+++ b/include/osgViewer/ViewerBase
@@ -106,6 +106,15 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
 
         /** Get the end barrier position.*/
         BarrierPosition getEndBarrierPosition() const { return _endBarrierPosition; }
+        
+        /** Set the end barrier operation. \c op may be one of GL_FLUSH, GL_FINISH,
+         * or NO_OPERATION. NO_OPERATION is the default. Per BarrierOperation::operator()(),
+         * a glFlush() command, glFinish() command, or no additional OpenGL command will be
+         * issued before entering the end barrier. */
+        void setEndBarrierOperation(const osg::BarrierOperation::PreBlockOp& op) { _endBarrierOperation = op; }
+        
+        /** Get the end barrier operation. */
+        osg::BarrierOperation::PreBlockOp getEndBarrierOperation() const { return _endBarrierOperation; }
 
 
 
@@ -309,6 +318,7 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
 
 
         BarrierPosition                                     _endBarrierPosition;
+        osg::BarrierOperation::PreBlockOp                   _endBarrierOperation;
 
         osg::ref_ptr<osg::BarrierOperation>                 _startRenderingBarrier;
         osg::ref_ptr<osg::BarrierOperation>                 _endRenderingDispatchBarrier;
diff --git a/src/osgViewer/ViewerBase.cpp b/src/osgViewer/ViewerBase.cpp
index 3874b0b7d..1a96ebfab 100644
--- a/src/osgViewer/ViewerBase.cpp
+++ b/src/osgViewer/ViewerBase.cpp
@@ -60,6 +60,7 @@ void ViewerBase::viewerBaseInit()
     _threadingModel = AutomaticSelection;
     _threadsRunning = false;
     _endBarrierPosition = AfterSwapBuffers;
+    _endBarrierOperation = osg::BarrierOperation::NO_OPERATION;
     _requestRedraw = true;
     _requestContinousUpdate = false;
 
@@ -355,7 +356,7 @@ void ViewerBase::startThreading()
 
     if (numThreadsOnEndBarrier>1)
     {
-        _endRenderingDispatchBarrier = new osg::BarrierOperation(numThreadsOnEndBarrier, osg::BarrierOperation::NO_OPERATION);
+        _endRenderingDispatchBarrier = new osg::BarrierOperation(numThreadsOnEndBarrier, _endBarrierOperation);
     }