Added s/getContinousUpdate(bool) method to OverlayNode.

examples/osgsimulation/osgsimulation.cpp

@@ -309,7 +309,10 @@ int main(int argc, char **argv)
         osg::ref_ptr<osgSim::OverlayNode> overlayNode;
         if (insertOverlayNode)
         {
+        
             overlayNode = new osgSim::OverlayNode;
+            
+            // insert the OverlayNode between the coordinate system node and its children.
             for(unsigned int i=0; i<csn->getNumChildren(); ++i)
             {
                 overlayNode->addChild( csn->getChild(i) );
@@ -317,6 +320,10 @@ int main(int argc, char **argv)
 
             csn->removeChild(0, csn->getNumChildren());
             csn->addChild(overlayNode.get());
+            
+            // tell the overlay node to continously update its overlay texture
+            // as we know we'll be tracking a moving target.
+            overlayNode->setContinousUpdate(true);
         }
         
         

include/osgSim/OverlayNode

@@ -44,9 +44,15 @@ class OSGSIM_EXPORT OverlayNode : public osg::Group
         /** Get the const overlay subgraph which will be render to texture.*/
         const osg::Node* getOverlaySubgraph() const { return _overlaySubgraph.get(); }
         
-        /** Inform the OveralNode that the overlay texture needs to be updated.*/
+        /** Inform the OverlayNode that the overlay texture needs to be updated.*/
         void dirtyOverlayTexture();
         
+        /** Set whether the OverlayNode should update the overlay texture on every frame.*/
+        void setContinousUpdate(bool update) { _continousUpdate = update; }
+
+        /** Get whether the OverlayNode should update the overlay texture on every frame.*/
+        bool getContinousUpdate() const { return _continousUpdate; }
+
         /** Set the texture unit that the texture should be assigned to.*/
         void setOverlayTextureUnit(unsigned int unit);
 
@@ -85,6 +91,8 @@ class OSGSIM_EXPORT OverlayNode : public osg::Group
         unsigned int                    _textureSizeHint;
         osg::ref_ptr<osg::Texture2D>    _texture;
 
+        bool                            _continousUpdate;
+        osg::BoundingSphere             _overlaySubgraphBound;
 };
 
 }

src/osgSim/OverlayNode.cpp

@@ -21,7 +21,8 @@ using namespace osgSim;
 
 OverlayNode::OverlayNode():
     _textureUnit(1),
-    _textureSizeHint(1024)
+    _textureSizeHint(1024),
+    _continousUpdate(false)
 {
     init();
 }
@@ -30,7 +31,8 @@ OverlayNode::OverlayNode(const OverlayNode& copy, const osg::CopyOp& copyop):
     Group(copy,copyop),
     _overlaySubgraph(copy._overlaySubgraph),
     _textureUnit(copy._textureUnit),
-    _textureSizeHint(copy._textureSizeHint)
+    _textureSizeHint(copy._textureSizeHint),
+    _continousUpdate(copy._continousUpdate)
 {
     init();
 }
@@ -102,7 +104,7 @@ void OverlayNode::traverse(osg::NodeVisitor& nv)
     unsigned int contextID = cv->getState()!=0 ? cv->getState()->getContextID() : 0;
 
     // if we need to redraw then do cull traversal on camera.
-    if (!_textureObjectValidList[contextID])
+    if (!_textureObjectValidList[contextID] || _continousUpdate)
     {
     
         // now compute the camera's view and projection matrix to point at the shadower (the camera's children)
@@ -112,12 +114,11 @@ void OverlayNode::traverse(osg::NodeVisitor& nv)
             bs.expandBy(_camera->getChild(i)->getBound());
         }
 
-        if (!bs.valid())
+        if (bs.valid())
         {
-            osg::notify(osg::WARN) << "OverlayNode::traverse() - bb invalid"<<_camera.get()<<std::endl;
+            // update the bounding volume for later testing
-            return;
+            // whether the overlay can be seen or not.
-        }
+            _overlaySubgraphBound = bs;
-
 
             // see if we are within a coordinate system node.
             osg::CoordinateSystemNode* csn = 0;
@@ -183,9 +184,23 @@ void OverlayNode::traverse(osg::NodeVisitor& nv)
 
             _textureObjectValidList[contextID] = 1;
         }
+    }
     
     
     // now set up the drawing of the main scene.
+#if 0 
+    // Disable for time being as _overlaySubgraphBound isn't accurate for
+    // detecting whether the overaly texture will sit over affect the rendering
+    // of the children of the OverlayNode.  Frustrum intersection may prove more
+    // fruitful.
+
+    // note needs to use bound when captured not current bound.
+    if (!_overlaySubgraphBound.valid() || cv->isCulled(_overlaySubgraphBound))
+    {
+        Group::traverse(nv);
+    }
+    else
+#endif
     {
         _texgenNode->accept(*cv);