From 20fd80de3a16f8c35f601eb778b8940637af1273 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 21 May 2014 09:45:11 +0000
Subject: [PATCH] Improved handling of callback object to open the door to use
 of general osg::CallbackObject as mechnisms for something simialr to Qt's
 signal/slot mechanism.

---
 include/osgUI/Widget | 12 ++++++-
 src/osgUI/Widget.cpp | 79 +++++++++-----------------------------------
 2 files changed, 27 insertions(+), 64 deletions(-)

diff --git a/include/osgUI/Widget b/include/osgUI/Widget
index 365366fa5..ca2235d8f 100644
--- a/include/osgUI/Widget
+++ b/include/osgUI/Widget
@@ -16,6 +16,7 @@
 
 #include <osg/Group>
 #include <osg/BoundingBox>
+#include <osg/ScriptEngine>
 #include <osgGA/Event>
 #include <osgGA/EventVisitor>
 
@@ -44,6 +45,7 @@ public:
     virtual void createGraphics();
     virtual void createGraphicsImplementation();
 
+
     virtual void setExtents(const osg::BoundingBoxf& bb);
     const osg::BoundingBoxf& getExtents() const { return _extents; }
 
@@ -83,6 +85,15 @@ public:
     /** get whether the widget has focus or not.*/
     virtual bool getHasEventFocus() const;
 
+
+    /** invoke all callbacks with specified names providing input and output parameters.*/
+    bool runCallbacks(const std::string& name, osg::Parameters& inputParameters, osg::Parameters& outputParameters) { return osg::runNamedCallbackObjects(this, name, inputParameters, outputParameters); }
+
+    /** invoke all callbacks with specified names without any specified input or output parameters.*/
+    bool runCallbacks(const std::string& name) { osg::Parameters inputParameters, outputParameters; return osg::runNamedCallbackObjects(this, name, inputParameters, outputParameters); }
+
+
+    /** Compute the bounding sphere of the widget.*/
     virtual osg::BoundingSphere computeBound() const;
 
     /** update any focus related graphics+state to the focused state.*/
@@ -108,7 +119,6 @@ protected:
     osg::ref_ptr<AlignmentSettings> _alignmentSettings;
     osg::ref_ptr<FrameSettings> _frameSettings;
     osg::ref_ptr<TextSettings> _textSettings;
-
 };
 
 }
diff --git a/src/osgUI/Widget.cpp b/src/osgUI/Widget.cpp
index 293a7bff2..090e0311e 100644
--- a/src/osgUI/Widget.cpp
+++ b/src/osgUI/Widget.cpp
@@ -156,15 +156,7 @@ bool Widget::getHasEventFocus() const
 
 void Widget::enter()
 {
-    osg::CallbackObject* co = osg::getCallbackObject(this, "enter");
-    if (co)
-    {
-        co->run(this);
-    }
-    else
-    {
-        enterImplementation();
-    }
+    if (!runCallbacks("enter")) enterImplementation();
 }
 
 void Widget::enterImplementation()
@@ -174,15 +166,7 @@ void Widget::enterImplementation()
 
 void Widget::leave()
 {
-    osg::CallbackObject* co = osg::getCallbackObject(this, "leave");
-    if (co)
-    {
-        co->run(this);
-    }
-    else
-    {
-        leaveImplementation();
-    }
+    if (!runCallbacks("leave")) leaveImplementation();
 }
 
 void Widget::leaveImplementation()
@@ -192,25 +176,16 @@ void Widget::leaveImplementation()
 
 void Widget::traverse(osg::NodeVisitor& nv)
 {
-    osg::CallbackObject* co = osg::getCallbackObject(this, "traverse");
-    if (co)
+    if (nv.referenceCount()!=0)
     {
-        // currently lua scripting takes a ref count so messes up handling of NodeVisitor's created on stack,
-        // so don't attempt to call the sctipt.
-        if (nv.referenceCount()==0)
-        {
-            traverseImplementation(nv);
-            return;
-        }
-
         osg::Parameters inputParameters, outputParameters;
         inputParameters.push_back(&nv);
-        co->run(this, inputParameters, outputParameters);
-    }
-    else
-    {
-        traverseImplementation(nv);
+        runCallbacks("traverse",inputParameters, outputParameters);
+        return;
     }
+
+    traverseImplementation(nv);
+
 }
 
 void Widget::traverseImplementation(osg::NodeVisitor& nv)
@@ -250,37 +225,24 @@ void Widget::traverseImplementation(osg::NodeVisitor& nv)
 
 bool Widget::handle(osgGA::EventVisitor* ev, osgGA::Event* event)
 {
-    osg::CallbackObject* co = osg::getCallbackObject(this, "handle");
-    if (co)
+    // currently lua scripting takes a ref count so messes up handling of NodeVisitor's created on stack,
+    // so don't attempt to call the sctipt.
+    if (ev->referenceCount()!=0)
     {
-        // currently lua scripting takes a ref count so messes up handling of NodeVisitor's created on stack,
-        // so don't attempt to call the sctipt.
-        if (ev->referenceCount()==0)
-        {
-            return handleImplementation(ev, event);
-        }
-
         osg::Parameters inputParameters, outputParameters;
         inputParameters.push_back(ev);
         inputParameters.push_back(event);
-        if (co->run(this, inputParameters, outputParameters))
+        if (runCallbacks("handle",inputParameters, outputParameters))
         {
             if (outputParameters.size()>=1)
             {
                 osg::BoolValueObject* bvo = dynamic_cast<osg::BoolValueObject*>(outputParameters[0].get());
-                if (bvo)
-                {
-                    return bvo->getValue();
-                }
-                return false;
+                return bvo ? bvo->getValue() : false;
             }
         }
-        return false;
-    }
-    else
-    {
-        return handleImplementation(ev, event);
     }
+
+    return handleImplementation(ev, event);
 }
 
 bool Widget::handleImplementation(osgGA::EventVisitor* ev, osgGA::Event* event)
@@ -311,16 +273,7 @@ void Widget::dirty()
 
 void Widget::createGraphics()
 {
-    osg::CallbackObject* co = osg::getCallbackObject(this, "createGraphics");
-    if (co)
-    {
-        co->run(this);
-    }
-    else
-    {
-        createGraphicsImplementation();
-    }
-
+    if (!runCallbacks("createGraphics")) createGraphicsImplementation();
 }
 
 void Widget::createGraphicsImplementation()