Added OveralyNode into VS project file, and fleshed out more code in the OveralyNode implementation.

src/osgSim/OverlayNode.cpp

@@ -11,26 +11,113 @@
  * OpenSceneGraph Public License for more details.
 */
 
+#include <osg/Texture2D>
+#include <osgUtil/CullVisitor>
 #include <osgSim/OverlayNode>
 
 using namespace osgSim;
 
-OverlayNode::OverlayNode()
+// use this cull callback to allow the camera to traverse the OverlaySubgraph's children without
+// actuall having them assigned as children to the camea itself.  This make the camera a
+// decorator without ever directly being assigned to it. 
+class OverlayTraverseNodeCallback : public osg::NodeCallback
 {
+public:
+
+    OverlayTraverseNodeCallback(osg::Node* node):_node(node) {}                                                       
+
+    virtual void operator()(osg::Node*, osg::NodeVisitor* nv)
+    {
+        _node->accept(*nv);
+    }
+    
+    osg::Node* _node;
+};
+
+OverlayNode::OverlayNode():
+    _textureUnit(0)
+{
+    init();
 }
 
-OverlayNode::OverlayNode(const OverlayNode& es, const osg::CopyOp& copyop)
+OverlayNode::OverlayNode(const OverlayNode& copy, const osg::CopyOp& copyop):
+    Group(copy,copyop),
+    _overlaySubgraph(copy._overlaySubgraph),
+    _textureUnit(copy._textureUnit)
 {
+    init();
 }
 
+void OverlayNode::init()
+{
+    _camera = new osg::CameraNode;
+
+    _texgenNode = new osg::TexGenNode;
+    _texgenNode->setTextureUnit(_textureUnit);
+
+    _texture = new osg::Texture2D;
+
+    _mainSubgraphStateSet = new osg::StateSet;
+    _mainSubgraphStateSet->setTextureAttributeAndModes(_textureUnit, _texture.get(), osg::StateAttribute::ON);
+}
+
+
 void OverlayNode::traverse(osg::NodeVisitor& nv)
 {
+    if (nv.getVisitorType() != osg::NodeVisitor::CULL_VISITOR)
+    {
+        Group::traverse(nv);
+        return;
+    }
+
+    osgUtil::CullVisitor* cv = dynamic_cast<osgUtil::CullVisitor*>(&nv);
+    if (!cv)
+    {
+        Group::traverse(nv);
+        return;
+    }
+    
+    unsigned int contextID = cv->getState()!=0 ? cv->getState()->getContextID() : 0;
+
+    // if we need to redraw then do cull traversal on camera.
+    if (!_textureObjectValidList[contextID])
+    {
+        _camera->accept(*cv);
+        
+        _textureObjectValidList[contextID] = 1;
+    }
+    
+    
+    // now set up the drawing of the main scene.
+    {
+        _texgenNode->accept(*cv);
+    
+        // push the stateset.
+        cv->pushStateSet(_mainSubgraphStateSet.get());
+
+        Group::traverse(nv);
+
+        cv->popStateSet();
+    }
 }
 
 void OverlayNode::setOverlaySubgraph(osg::Node* node)
 {
+    _overlaySubgraph = node;
+    dirtyOverlayTexture();
 }
 
 void OverlayNode::dirtyOverlayTexture()
 {
+    _textureObjectValidList.setAllElementsTo(0);
+}
+
+void OverlayNode::setOverlayTextureUnit(unsigned int unit)
+{
+    if (_textureUnit==unit) return;
+    
+    _texgenNode->setTextureUnit(unit);
+    
+    _mainSubgraphStateSet->clear();
+    _mainSubgraphStateSet->setTextureAttributeAndModes(_textureUnit, _texture.get(), osg::StateAttribute::ON);
 }