From 5633fa12478ae557b442219f3e4da73429d4cf1e Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Mon, 1 Sep 2014 19:13:35 +0000
Subject: [PATCH] Added DragCallback class to help dialog dragging support.
 Introduced a new Widget::computeExtentsPositionInLocalCoordinates() method
 that intersects with a ray through mouse pointer and the extents of the
 widget.

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14429 16af8721-9629-0410-8352-f15c8da7e697
---
 include/osgUI/Callbacks  |  65 +++++++++++++++++++
 include/osgUI/Widget     |  31 +++++----
 src/osgUI/CMakeLists.txt |   3 +
 src/osgUI/Callbacks.cpp  | 132 +++++++++++++++++++++++++++++++++++++++
 src/osgUI/Dialog.cpp     |  28 +++++++--
 src/osgUI/LineEdit.cpp   |   2 +-
 src/osgUI/Widget.cpp     | 111 +++++++++++++++++++++++++-------
 7 files changed, 331 insertions(+), 41 deletions(-)
 create mode 100644 include/osgUI/Callbacks
 create mode 100644 src/osgUI/Callbacks.cpp

diff --git a/include/osgUI/Callbacks b/include/osgUI/Callbacks
new file mode 100644
index 000000000..c1c3ffbc7
--- /dev/null
+++ b/include/osgUI/Callbacks
@@ -0,0 +1,65 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGUI_CALLBACKS
+#define OSGUI_CALLBACKS
+
+#include <osg/Callback>
+#include <osgGA/EventVisitor>
+
+#include <osgUI/Export>
+
+namespace osgUI
+{
+
+class OSGUI_EXPORT HandleCallback : public osg::CallbackObject
+{
+public:
+    HandleCallback();
+    HandleCallback(const HandleCallback& hc, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+    META_Object(osgUI, HandleCallback);
+
+    virtual bool run(osg::Object* object, osg::Parameters& inputParameters, osg::Parameters& outputParameters) const;
+    virtual bool handle(osgGA::EventVisitor* ev, osgGA::Event* event) const;
+
+protected:
+    virtual ~HandleCallback() {}
+};
+
+
+class OSGUI_EXPORT DragCallback : public HandleCallback
+{
+public:
+    DragCallback();
+    DragCallback(const DragCallback& dc, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+    META_Object(osgUI, DragCallback);
+
+    void setDragging(bool v) { _dragging = v; }
+    bool getDragging() const { return _dragging; }
+
+    void setPreviousPosition(const osg::Vec3d& position) { _previousPosition = position; }
+    const osg::Vec3d& getPreviousPosition() const { return _previousPosition; }
+
+    virtual bool handle(osgGA::EventVisitor* ev, osgGA::Event* event) const;
+
+protected:
+    virtual ~DragCallback() {}
+
+    bool        _dragging;
+    osg::Vec3d  _previousPosition;
+
+};
+
+}
+
+#endif
diff --git a/include/osgUI/Widget b/include/osgUI/Widget
index 1e0e04e56..dc285a993 100644
--- a/include/osgUI/Widget
+++ b/include/osgUI/Widget
@@ -40,7 +40,8 @@ public:
 
     typedef std::vector<osgUtil::LineSegmentIntersector::Intersection> Intersections;
     virtual bool computeIntersections(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, Intersections& intersections, osg::Node::NodeMask traversalMask = 0xffffffff) const;
-    virtual bool computePositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3& localPosition) const;
+    virtual bool computePositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3d& localPosition) const;
+    virtual bool computeExtentsPositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3d& localPosition, bool withinExtents=true) const;
 
     virtual void dirty();
 
@@ -85,6 +86,11 @@ public:
     TextSettings* getTextSettings() { return _textSettings.get(); }
     const TextSettings* getTextSettings() const { return _textSettings.get(); }
 
+    /** set whether the widget should fill the extents of its background.*/
+    virtual void setAutoFillBackground(bool enabled) { _autoFillBackground = enabled; }
+    /** get whether the widget should fill the extents of its background.*/
+    virtual bool getAutoFillBackground() const { return _autoFillBackground; }
+
     /** set the visibility of the widget.*/
     virtual void setVisible(bool visible) { _visible = visible; }
     /** get the visibility of the widget.*/
@@ -141,22 +147,23 @@ public:
 protected:
     virtual ~Widget() {}
 
-    FocusBehaviour      _focusBehaviour;
-    bool                _hasEventFocus;
-    bool                _graphicsInitialized;
+    FocusBehaviour                      _focusBehaviour;
+    bool                                _hasEventFocus;
+    bool                                _graphicsInitialized;
 
-    GraphicsSubgraphMap _graphicsSubgraphMap;
+    GraphicsSubgraphMap                 _graphicsSubgraphMap;
 
-    osg::BoundingBoxf   _extents;
+    osg::BoundingBoxf                   _extents;
 
-    osg::ref_ptr<Style> _style;
+    osg::ref_ptr<Style>                 _style;
 
-    osg::ref_ptr<AlignmentSettings> _alignmentSettings;
-    osg::ref_ptr<FrameSettings> _frameSettings;
-    osg::ref_ptr<TextSettings> _textSettings;
+    osg::ref_ptr<AlignmentSettings>     _alignmentSettings;
+    osg::ref_ptr<FrameSettings>         _frameSettings;
+    osg::ref_ptr<TextSettings>          _textSettings;
+    bool                                _autoFillBackground;
 
-    bool                _visible;
-    bool                _enabled;
+    bool                                _visible;
+    bool                                _enabled;
 };
 
 }
diff --git a/src/osgUI/CMakeLists.txt b/src/osgUI/CMakeLists.txt
index 06b7313ea..fea8864d5 100644
--- a/src/osgUI/CMakeLists.txt
+++ b/src/osgUI/CMakeLists.txt
@@ -17,6 +17,7 @@ SET(TARGET_H
     ${HEADER_PATH}/Popup
     ${HEADER_PATH}/PushButton
     ${HEADER_PATH}/ComboBox
+    ${HEADER_PATH}/Callbacks
     ${HEADER_PATH}/Style
     ${HEADER_PATH}/AlignmentSettings
     ${HEADER_PATH}/FrameSettings
@@ -33,6 +34,7 @@ SET(TARGET_SRC
     Popup.cpp
     PushButton.cpp
     ComboBox.cpp
+    Callbacks.cpp
     Style.cpp
     AlignmentSettings.cpp
     FrameSettings.cpp
@@ -46,6 +48,7 @@ SET(TARGET_LIBRARIES
     osgGA
     osgUtil
     osgText
+    osgViewer
     osg
     OpenThreads
 )
diff --git a/src/osgUI/Callbacks.cpp b/src/osgUI/Callbacks.cpp
new file mode 100644
index 000000000..834178d8d
--- /dev/null
+++ b/src/osgUI/Callbacks.cpp
@@ -0,0 +1,132 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osgUI/Callbacks>
+#include <osgUI/Widget>
+#include <osg/ValueObject>
+#include <osg/MatrixTransform>
+#include <osg/io_utils>
+
+using namespace osgUI;
+
+HandleCallback::HandleCallback()
+{
+    setName("handle");
+}
+
+HandleCallback::HandleCallback(const HandleCallback& hc, const osg::CopyOp& copyop):
+    osg::CallbackObject(hc, copyop)
+{
+}
+
+bool HandleCallback::run(osg::Object* object, osg::Parameters& inputParameters, osg::Parameters& outputParameters) const
+{
+    if (inputParameters.size()>=2)
+    {
+        osgGA::EventVisitor* ev = dynamic_cast<osgGA::EventVisitor*>(inputParameters[0].get());
+        osgGA::Event* event = dynamic_cast<osgGA::Event*>(inputParameters[1].get());
+        if (ev && event)
+        {
+            outputParameters.push_back(new osg::BoolValueObject("return",handle(ev,event)));
+            return true;
+        }
+    }
+    return false;
+}
+
+bool HandleCallback::handle(osgGA::EventVisitor* ev, osgGA::Event* event) const
+{
+    return false;
+}
+
+
+DragCallback::DragCallback():
+    _dragging(false)
+{
+}
+
+DragCallback::DragCallback(const DragCallback& hc, const osg::CopyOp& copyop):
+    HandleCallback(hc, copyop)
+{
+}
+
+bool DragCallback::handle(osgGA::EventVisitor* ev, osgGA::Event* event) const
+{
+    osgGA::GUIEventAdapter* ea = event ? event->asGUIEventAdapter() : 0;
+    if (!ev || !ea) return false;
+
+    osgUI::Widget* widget = dynamic_cast<osgUI::Widget*>(ev->getNodePath().empty() ? 0 : ev->getNodePath().back());
+    if (widget && widget->getHasEventFocus())
+    {
+        DragCallback* dc = const_cast<DragCallback*>(this);
+        switch(ea->getEventType())
+        {
+            case(osgGA::GUIEventAdapter::PUSH):
+            {
+                dc->_dragging = (ea->getButtonMask()==osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON);
+                if (dc->_dragging)
+                {
+                    osg::Vec3d localPosition;
+#if 0
+                    if (widget->computePositionInLocalCoordinates(ev, ea, localPosition))
+#else
+                    if (widget->computeExtentsPositionInLocalCoordinates(ev, ea, localPosition))
+#endif
+                    {
+                        dc->_previousPosition = localPosition;
+                        OSG_NOTICE<<"* Move to local"<<_previousPosition<<std::endl;
+                    }
+                }
+                break;
+            }
+            case(osgGA::GUIEventAdapter::DRAG):
+            {
+                if (dc->_dragging)
+                {
+                    osg::Transform* transform = 0;
+                    for(osg::NodePath::reverse_iterator itr = ev->getNodePath().rbegin();
+                        itr != ev->getNodePath().rend();
+                        ++itr)
+                    {
+                        if ((*itr)->asTransform())
+                        {
+                            transform = (*itr)->asTransform();
+                            break;
+                        }
+                    }
+                    if (transform)
+                    {
+                        osg::Vec3d position;
+                        if (widget->computeExtentsPositionInLocalCoordinates(ev, ea, position, false))
+                        {
+                            osg::Vec3d delta = position-_previousPosition;
+                            osg::MatrixTransform* mt = transform->asMatrixTransform();
+                            mt->setMatrix(osg::Matrixd::translate(delta)*mt->getMatrix());
+                            // OSG_NOTICE<<"Move to local "<<position<<", "<<position-_previousPosition<<std::endl;
+                        }
+                    }
+                    else
+                    {
+                        OSG_NOTICE<<"Failed to drag, No Transform to move"<<std::endl;
+                    }
+                }
+                break;
+            }
+            case(osgGA::GUIEventAdapter::RELEASE):
+                dc->_dragging = false;
+            default:
+                break;
+        }
+    }
+    return false;
+}
diff --git a/src/osgUI/Dialog.cpp b/src/osgUI/Dialog.cpp
index 890bea42f..cd0378970 100644
--- a/src/osgUI/Dialog.cpp
+++ b/src/osgUI/Dialog.cpp
@@ -13,6 +13,10 @@
 
 
 #include <osgUI/Dialog>
+#include <osgUI/PushButton>
+#include <osgUI/Label>
+#include <osgUI/Callbacks>
+
 #include <osgText/String>
 #include <osgText/Font>
 #include <osgText/Text>
@@ -62,29 +66,41 @@ void Dialog::createGraphicsImplementation()
     osg::Vec4 dialogTitleBackgroundColor(0.5,0.5,1.0,1.0);
 
     _group->addChild( style->createPanel(_extents, dialogBackgroundColor) );
+
     _group->addChild( style->createPanel(titleBarExents, dialogTitleBackgroundColor) );
 
-    osg::BoundingBox dialogWithTileExtents(_extents);
-    dialogWithTileExtents.expandBy(titleBarExents);
+    osg::BoundingBox dialogWithTitleExtents(_extents);
+    dialogWithTitleExtents.expandBy(titleBarExents);
 
     bool requiresFrame = (getFrameSettings() && getFrameSettings()->getShape()!=osgUI::FrameSettings::NO_FRAME);
-    if (requiresFrame) { _group->addChild(style->createFrame(dialogWithTileExtents, getFrameSettings(), dialogBackgroundColor)); }
+    if (requiresFrame) { _group->addChild(style->createFrame(dialogWithTitleExtents, getFrameSettings(), dialogBackgroundColor)); }
 
     OSG_NOTICE<<"Dialog::_extents ("<<_extents.xMin()<<", "<<_extents.yMin()<<", "<<_extents.zMin()<<"), ("<<_extents.xMax()<<", "<<_extents.yMax()<<", "<<_extents.zMax()<<")"<<std::endl;
     OSG_NOTICE<<"Dialog::titleBarExents ("<<titleBarExents.xMin()<<", "<<titleBarExents.yMin()<<", "<<titleBarExents.zMin()<<"), ("<<titleBarExents.xMax()<<", "<<titleBarExents.yMax()<<", "<<titleBarExents.zMax()<<")"<<std::endl;
-    OSG_NOTICE<<"Dialog::dialogWithTileExtents ("<<dialogWithTileExtents.xMin()<<", "<<dialogWithTileExtents.yMin()<<", "<<dialogWithTileExtents.zMin()<<"), ("<<dialogWithTileExtents.xMax()<<", "<<dialogWithTileExtents.yMax()<<", "<<dialogWithTileExtents.zMax()<<")"<<std::endl;
+    OSG_NOTICE<<"Dialog::dialogWithTitleExtents ("<<dialogWithTitleExtents.xMin()<<", "<<dialogWithTitleExtents.yMin()<<", "<<dialogWithTitleExtents.zMin()<<"), ("<<dialogWithTitleExtents.xMax()<<", "<<dialogWithTitleExtents.yMax()<<", "<<dialogWithTitleExtents.zMax()<<")"<<std::endl;
 
+#if 0
     osg::ref_ptr<Node> node = style->createText(titleBarExents, getAlignmentSettings(), getTextSettings(), _title);
     _titleDrawable = dynamic_cast<osgText::Text*>(node.get());
     _titleDrawable->setDataVariance(osg::Object::DYNAMIC);
     _group->addChild(_titleDrawable.get());
+#endif
+
+    osg::ref_ptr<Label> titleLabel = new osgUI::Label;
+    titleLabel->setExtents(titleBarExents);
+    titleLabel->setText(_title);
+    titleLabel->setAlignmentSettings(getAlignmentSettings());
+    titleLabel->setTextSettings(getTextSettings());
+    titleLabel->setFrameSettings(getFrameSettings());
+    titleLabel->getOrCreateUserDataContainer()->addUserObject(new osgUI::DragCallback);
+    addChild(titleLabel.get());
 
     style->setupDialogStateSet(getOrCreateStateSet(), 5);
-    style->setupClipStateSet(dialogWithTileExtents, getOrCreateStateSet());
+    style->setupClipStateSet(dialogWithTitleExtents, getOrCreateStateSet());
 
     // render before the subgraph
     setGraphicsSubgraph(-1, _group.get());
 
     // render after the subgraph
-    setGraphicsSubgraph(1, style->createDepthSetPanel(dialogWithTileExtents));
+    setGraphicsSubgraph(1, style->createDepthSetPanel(dialogWithTitleExtents));
 }
diff --git a/src/osgUI/LineEdit.cpp b/src/osgUI/LineEdit.cpp
index e2f824f02..d10f63512 100644
--- a/src/osgUI/LineEdit.cpp
+++ b/src/osgUI/LineEdit.cpp
@@ -166,7 +166,7 @@ void LineEdit::createGraphicsImplementation()
     // clear background of edit region
     _backgroundSwitch = new osg::Switch;
     _backgroundSwitch->addChild(style->createPanel(extents, osg::Vec4(unFocused, unFocused,unFocused, 1.0)));
-    _backgroundSwitch->addChild(style->createPanel(extents, osg::Vec4(withFocus,withFocus,withFocus,1.0)));
+    _backgroundSwitch->addChild(style->createPanel(extents, osg::Vec4(withFocus, withFocus, withFocus,1.0)));
     _backgroundSwitch->setSingleChildOn(0);
     group->addChild(_backgroundSwitch.get());
 
diff --git a/src/osgUI/Widget.cpp b/src/osgUI/Widget.cpp
index ff3d7d724..ae57e38e2 100644
--- a/src/osgUI/Widget.cpp
+++ b/src/osgUI/Widget.cpp
@@ -22,6 +22,7 @@
 #include <osgUI/Widget>
 #include <osgGA/EventVisitor>
 #include <osgGA/GUIActionAdapter>
+#include <osgViewer/View>
 
 #include <algorithm>
 
@@ -31,6 +32,7 @@ Widget::Widget():
     _focusBehaviour(FOCUS_FOLLOWS_POINTER),
     _hasEventFocus(false),
     _graphicsInitialized(false),
+    _autoFillBackground(false),
     _visible(true),
     _enabled(true)
 {
@@ -45,6 +47,7 @@ Widget::Widget(const Widget& widget, const osg::CopyOp& copyop):
     _alignmentSettings(osg::clone(widget._alignmentSettings.get(), copyop)),
     _frameSettings(osg::clone(widget._frameSettings.get(), copyop)),
     _textSettings(osg::clone(widget._textSettings.get(), copyop)),
+    _autoFillBackground(widget._autoFillBackground),
     _visible(widget._visible),
     _enabled(widget._enabled)
 {
@@ -72,20 +75,24 @@ void Widget::updateFocus(osg::NodeVisitor& nv)
             osgGA::GUIEventAdapter* ea = (*itr)->asGUIEventAdapter();
             if (ea)
             {
+                int numButtonsPressed = 0;
+                if (ea->getEventType()==osgGA::GUIEventAdapter::PUSH)
+                {
+                    if (ea->getButtonMask()&osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON) ++numButtonsPressed;
+                    if (ea->getButtonMask()&osgGA::GUIEventAdapter::MIDDLE_MOUSE_BUTTON) ++numButtonsPressed;
+                    if (ea->getButtonMask()&osgGA::GUIEventAdapter::RIGHT_MOUSE_BUTTON) ++numButtonsPressed;
+                }
+
                 bool previousFocus = _hasEventFocus;
                 if (_focusBehaviour==CLICK_TO_FOCUS)
                 {
                     if (ea->getEventType()==osgGA::GUIEventAdapter::PUSH)
                     {
-                        int numButtonsPressed = 0;
-                        if (ea->getButtonMask()&osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON) ++numButtonsPressed;
-                        if (ea->getButtonMask()&osgGA::GUIEventAdapter::MIDDLE_MOUSE_BUTTON) ++numButtonsPressed;
-                        if (ea->getButtonMask()&osgGA::GUIEventAdapter::RIGHT_MOUSE_BUTTON) ++numButtonsPressed;
-
                         if (numButtonsPressed==1)
                         {
-                            osgUtil::LineSegmentIntersector::Intersections intersections;
-                            bool withinWidget = aa->computeIntersections(*ea, nv.getNodePath(), intersections);
+                            osg::Vec3d intersection;
+                            bool withinWidget = computeExtentsPositionInLocalCoordinates(ev, ea, intersection);
+
                             if (withinWidget) _hasEventFocus = true;
                             else _hasEventFocus = false;
                         }
@@ -114,30 +121,30 @@ void Widget::updateFocus(osg::NodeVisitor& nv)
 
                     if (checkWithinWidget)
                     {
-#if 0
-                        osgUtil::LineSegmentIntersector::Intersections intersections;
-                        bool withinWidget = aa->computeIntersections(*ea, nv.getNodePath(), intersections);
-#else
-                        Intersections intersections;
-                        bool withinWidget = computeIntersections( ev, ea, intersections);
-#endif
+                        osg::Vec3d intersection;
+                        bool withinWidget = computeExtentsPositionInLocalCoordinates(ev, ea, intersection);
 
                         _hasEventFocus = withinWidget;
                     }
                 }
 
+                if (numButtonsPressed!=0)
+                {
+                    osgViewer::View* view = dynamic_cast<osgViewer::View*>(aa);
+                    if (view && view->getCameraManipulator())
+                    {
+                        view->getCameraManipulator()->finishAnimation();
+                        view->requestContinuousUpdate( false );
+                    }
+                }
+
+
                 if (previousFocus != _hasEventFocus)
                 {
                     if (_hasEventFocus)
                     {
                         enter();
-#if 0
-                        if (view->getCameraManipulator())
-                        {
-                            view->getCameraManipulator()->finishAnimation();
-                            view->requestContinuousUpdate( false );
-                        }
-#endif
+
                     }
                     else
                     {
@@ -328,7 +335,7 @@ void Widget::releaseGLObjects(osg::State* state) const
 
 }
 
-bool Widget::computePositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3& localPosition) const
+bool Widget::computePositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3d& localPosition) const
 {
     osgGA::GUIActionAdapter* aa = ev ? ev->getActionAdapter() : 0;
     osgUtil::LineSegmentIntersector::Intersections intersections;
@@ -440,3 +447,63 @@ bool Widget::computeIntersections(osgGA::EventVisitor* ev, osgGA::GUIEventAdapte
     }
     return false;
 }
+
+
+bool Widget::computeExtentsPositionInLocalCoordinates(osgGA::EventVisitor* ev, osgGA::GUIEventAdapter* event, osg::Vec3d& localPosition, bool withinExtents) const
+{
+    //OSG_NOTICE<<"Widget::computeExtentsPositionInLocalCoordinates(()"<<std::endl;
+    const osg::Camera* camera = 0;
+    double x=0.0, y=0.0;
+    if (event->getNumPointerData()>=1)
+    {
+        const osgGA::PointerData* pd = event->getPointerData(event->getNumPointerData()-1);
+        camera = dynamic_cast<const osg::Camera*>(pd->object.get());
+        if (camera)
+        {
+            x = pd->getXnormalized();
+            y = pd->getYnormalized();
+        }
+    }
+    //OSG_NOTICE<<"   camera = "<<camera<<", x = "<<x<<", y="<<y<<std::endl;
+    if (!camera) return false;
+
+    const osg::NodePath& nodePath = ev->getNodePath();
+
+    osg::Matrixd matrix;
+    if (nodePath.size()>1)
+    {
+        osg::NodePath prunedNodePath(nodePath.begin(),nodePath.end()-1);
+        matrix = osg::computeLocalToWorld(prunedNodePath);
+    }
+
+    matrix.postMult(camera->getViewMatrix());
+    matrix.postMult(camera->getProjectionMatrix());
+
+    double zNear = -1.0;
+    double zFar = 1.0;
+
+    osg::Matrixd inverse;
+    inverse.invert(matrix);
+
+    osg::Vec3d startVertex = osg::Vec3d(x,y,zNear) * inverse;
+    osg::Vec3d endVertex = osg::Vec3d(x,y,zFar) * inverse;
+
+    //OSG_NOTICE<<"   startVertex("<<startVertex<<"(, endVertex("<<endVertex<<")"<<std::endl;
+
+
+    osg::Plane plane(0.0, 0.0, 1.0, _extents.zMax());
+
+    //OSG_NOTICE<<"   plane("<<plane<<")"<<std::endl;
+    double ds = plane.distance(startVertex);
+    double de = plane.distance(endVertex);
+    if (ds*de>0.0) return false;
+
+    double r = ds/(ds-de);
+    //OSG_NOTICE<<"   r = "<<r<<std::endl;
+
+    osg::Vec3d intersection = startVertex + (endVertex-startVertex)*r;
+    //OSG_NOTICE<<"    intersection = "<<intersection<<std::endl;
+    localPosition = intersection;
+
+    return withinExtents ? _extents.contains(localPosition, 1e-6) : true;
+}