From f767ab0cc967395aa4fe9573f2fbad4a9b762bae Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 7 Feb 2018 17:23:14 +0000
Subject: [PATCH] Refactored the event handler so that it contains a helper
 NodeVistor class rather than inherits from inappropriately using multiple
 inheritance.

---
 examples/osgsidebyside/osgsidebyside.cpp | 100 +++++++++++++----------
 1 file changed, 55 insertions(+), 45 deletions(-)

diff --git a/examples/osgsidebyside/osgsidebyside.cpp b/examples/osgsidebyside/osgsidebyside.cpp
index c4acad979..3117f6471 100644
--- a/examples/osgsidebyside/osgsidebyside.cpp
+++ b/examples/osgsidebyside/osgsidebyside.cpp
@@ -41,48 +41,15 @@ using namespace osg;
 using namespace osgGA;
 
 
-class SwitchDOFVisitor : public osg::NodeVisitor, public osgGA::GUIEventHandler
+class SwitchDOFHandler : public osgGA::GUIEventHandler
 {
 public:
-    SwitchDOFVisitor():
-      osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN)
+
+
+    SwitchDOFHandler()
     {
     }
 
-    SwitchDOFVisitor(const SwitchDOFVisitor& sdfv, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
-        osg::Object(sdfv, copyop),
-        osg::Callback(sdfv, copyop),
-        osg::NodeVisitor(sdfv, copyop),
-        osgGA::GUIEventHandler(sdfv, copyop)
-        {}
-
-    META_Object(osg, SwitchDOFVisitor)
-
-    virtual void apply(Group& node)
-    {
-        osgSim::MultiSwitch* pMSwitch = dynamic_cast<osgSim::MultiSwitch*>(&node);
-
-        if (pMSwitch)
-        {
-            mSwitches.push_back(pMSwitch);
-        }
-
-        osg::NodeVisitor::apply(node);
-    }
-
-    virtual void apply(Transform& node)
-    {
-        osgSim::DOFTransform* pDof = dynamic_cast<osgSim::DOFTransform*>(&node);
-
-        if (pDof)
-        {
-            mDofs.push_back(pDof);
-            pDof->setAnimationOn(true);
-        }
-
-        osg::NodeVisitor::apply(node);
-    }
-
     void nextSwitch()
     {
         for (size_t i=0; i < mSwitches.size(); i++)
@@ -156,9 +123,53 @@ public:
         return false;
     }
 
+    void collectNodesOfInterest(osg::Node* node)
+    {
+        CollectNodes cn(this);
+        node->accept(cn);
+    }
+
 private:
-    std::vector<osgSim::MultiSwitch*> mSwitches;
-    std::vector<osgSim::DOFTransform*> mDofs;
+
+    friend class CollectNodes;
+
+    class CollectNodes : public osg::NodeVisitor
+    {
+    public:
+        SwitchDOFHandler* _parent;
+
+        CollectNodes(SwitchDOFHandler* parent):
+            osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
+            _parent(parent)
+        {
+        }
+
+        virtual void apply(Group& node)
+        {
+            osgSim::MultiSwitch* pMSwitch = dynamic_cast<osgSim::MultiSwitch*>(&node);
+            if (pMSwitch)
+            {
+                _parent->mSwitches.push_back(pMSwitch);
+            }
+
+            traverse(node);
+        }
+
+        virtual void apply(Transform& node)
+        {
+            osgSim::DOFTransform* pDof = dynamic_cast<osgSim::DOFTransform*>(&node);
+            if (pDof)
+            {
+                _parent->mDofs.push_back(pDof);
+                pDof->setAnimationOn(true);
+            }
+
+            traverse(node);
+        }
+    };
+
+    std::vector< osg::ref_ptr<osgSim::MultiSwitch> > mSwitches;
+    std::vector< osg::ref_ptr<osgSim::DOFTransform> > mDofs;
 };
 
 void singleWindowSideBySideCameras(osgViewer::Viewer& viewer)
@@ -267,8 +278,8 @@ int main( int argc, char **argv )
     viewer.addEventHandler(new osgViewer::LODScaleHandler());
     viewer.addEventHandler(new osgGA::StateSetManipulator());
 
-    SwitchDOFVisitor* visit = new SwitchDOFVisitor;
-    viewer.addEventHandler(visit);
+    SwitchDOFHandler* switchOFHandler = new SwitchDOFHandler;
+    viewer.addEventHandler(switchOFHandler);
 
     // load the scene.
     osg::ref_ptr<osg::Node> loadedModel = osgDB::readRefNodeFiles(arguments);
@@ -294,13 +305,12 @@ int main( int argc, char **argv )
     group2->addChild(convertedModel.get());
     group2->setNodeMask(2);
 
-    // Activate DOF animations and collect switches
-    loadedModel->accept(*visit);
-    convertedModel->accept(*visit);
-
     group->addChild(group1);
     group->addChild(group2);
 
+    // Activate DOF animations and collect switches
+    switchOFHandler->collectNodesOfInterest(group);
+
     viewer.setSceneData(group);
 
     viewer.setThreadingModel(osgViewer::Viewer::DrawThreadPerContext);