DYT/Tool/OpenSceneGraph-3.6.5/include/osgEarth/MapNodeObserver
2024-12-25 07:49:36 +08:00

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/* -*-c++-*- */
/* osgEarth - Geospatial SDK for OpenSceneGraph
* Copyright 2020 Pelican Mapping
* http://osgearth.org
*
* osgEarth is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
*/
#ifndef OSGEARTH_MAP_NODE_OBSERVER_H
#define OSGEARTH_MAP_NODE_OBSERVER_H 1
#include <osgEarth/Common>
#include <osgEarth/MapNode>
namespace osgEarth
{
/**
* This is a marker class for objects (and nodes) that reference a MapNode.
*
* The usage pattern for this class is to include it as a superclass using
* multiple inheritance (if necessary) and to implement the set/get MapNode
* methods. If you store a local reference to the MapNode, you should use
* an osg::observer_ptr<> to do so!
*
* You can update as scene graph containing MapNodeObservers by using the
* MapNodeObserverSetter visitor.
*/
class /*header-only*/ MapNodeObserver
{
public:
/**
* Sets the map node's observer reference
*/
virtual void setMapNode( MapNode* mapNode ) =0;
/**
* Gets the map node from its observer reference
*/
virtual MapNode* getMapNode() =0;
/**
* dtor
*/
virtual ~MapNodeObserver() { }
};
/**
* Base class for a visitor that operates on MapNodeObserver instances
* found in a scene graph.
*/
class /*header-only*/ MapNodeObserverVisitor : public osg::NodeVisitor
{
public:
MapNodeObserverVisitor(osg::NodeVisitor::TraversalMode mode =osg::NodeVisitor::TRAVERSE_ALL_CHILDREN)
: osg::NodeVisitor( mode ) { }
virtual void apply( MapNodeObserver* m ) = 0;
void tryApply( MapNodeObserver* m )
{
if ( m ) apply( m );
}
void apply( osg::Node& node )
{
tryApply( dynamic_cast<MapNodeObserver*>(&node) );
tryApply( dynamic_cast<MapNodeObserver*>(node.getEventCallback()) );
tryApply( dynamic_cast<MapNodeObserver*>(node.getUpdateCallback()) );
tryApply( dynamic_cast<MapNodeObserver*>(node.getCullCallback()) );
traverse( node );
}
};
/**
* Visitor that traverses a graph and calls setMapNode() on each
* MapNodeObserver found.
*/
class /*header-only*/ MapNodeReplacer : public MapNodeObserverVisitor
{
public:
MapNodeReplacer( MapNode* mapNode ) : _mapNode(mapNode) { }
void apply( MapNodeObserver* m )
{
m->setMapNode( _mapNode.get() );
}
private:
osg::observer_ptr<MapNode> _mapNode;
};
} // namespace osgEarth
#endif // OSGEARTH_MAP_NODE_OBSERVER_H