Add asOccluderNode method to avoid dynamic casts in group child handling

include/osg/Node

@@ -42,6 +42,7 @@ class Node;
 class Switch;
 class Geode;
 class Camera;
+class OccluderNode;
 
 /** A vector of Nodes pointers which is used to describe the path from a root node to a descendant.*/
 typedef std::vector< Node* > NodePath;
@@ -132,6 +133,12 @@ class OSG_EXPORT Node : public Object
           * Equivalent to dynamic_cast<const Transform*>(this).*/
         virtual const Transform* asTransform() const { return 0; }
 
+        /** Convert 'this' into an OccluderNode pointer if Node is an OccluderNode, otherwise return 0.
+          * Equivalent to dynamic_cast<OccluderNode*>(this).*/
+        virtual OccluderNode* asOccluderNode() { return 0; }
+        /** Convert 'const this' into a const OccluderNode pointer if Node is an OccluderNode, otherwise return 0.
+          * Equivalent to dynamic_cast<const OccluderNode*>(this).*/
+        virtual const OccluderNode* asOccluderNode() const { return 0; }
 
 
         /** Convert 'this' into a Switch pointer if Node is a Switch, otherwise return 0.

include/osg/OccluderNode

@@ -34,6 +34,12 @@ class OSG_EXPORT OccluderNode : public Group
 
         META_Node(osg, OccluderNode);
 
+        /** Convert 'this' into an OccluderNode pointer if Node is an OccluderNode, otherwise return 0.
+          * Equivalent to dynamic_cast<OccluderNode*>(this).*/
+        virtual OccluderNode* asOccluderNode() { return this; }
+        /** Convert 'const this' into a const OccluderNode pointer if Node is an OccluderNode, otherwise return 0.
+          * Equivalent to dynamic_cast<const OccluderNode*>(this).*/
+        virtual const OccluderNode* asOccluderNode() const { return this; }
 
         /** Attach a ConvexPlanarOccluder to an OccluderNode.*/
         void setOccluder(ConvexPlanarOccluder* occluder) { _occluder = occluder; }

src/osg/Group.cpp

@@ -137,7 +137,7 @@ bool Group::insertChild( unsigned int index, Node *child )
     }
 
     if (child->getNumChildrenWithOccluderNodes()>0 ||
-        dynamic_cast<osg::OccluderNode*>(child))
+        child->asOccluderNode())
     {
         setNumChildrenWithOccluderNodes(
             getNumChildrenWithOccluderNodes()+1
@@ -190,7 +190,7 @@ bool Group::removeChildren(unsigned int pos,unsigned int numChildrenToRemove)
 
             if (child->getNumChildrenWithCullingDisabled()>0 || !child->getCullingActive()) ++numChildrenWithCullingDisabledRemoved;
 
-            if (child->getNumChildrenWithOccluderNodes()>0 || dynamic_cast<osg::OccluderNode*>(child)) ++numChildrenWithOccludersRemoved;
+            if (child->getNumChildrenWithOccluderNodes()>0 || child->asOccluderNode()) ++numChildrenWithOccludersRemoved;
 
         }
 
@@ -326,12 +326,12 @@ bool Group::setChild( unsigned  int i, Node* newNode )
         // so need to check and update if required.
         int delta_numChildrenWithOccluderNodes = 0;
         if (origNode->getNumChildrenWithOccluderNodes()>0 ||
-            dynamic_cast<osg::OccluderNode*>(origNode.get()))
+            origNode.get()->asOccluderNode())
         {
             --delta_numChildrenWithOccluderNodes;
         }
         if (newNode->getNumChildrenWithOccluderNodes()>0 ||
-            dynamic_cast<osg::OccluderNode*>(newNode))
+            newNode->asOccluderNode())
         {
             ++delta_numChildrenWithOccluderNodes;
         }