//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGGA_CAMERAMANIPULATOR
#define OSGGA_CAMERAMANIPULATOR 1

#include <osg/Camera>
#include <osg/Node>

#include <osgGA/Export>
#include <osgGA/GUIEventHandler>
#include <osgGA/GUIEventAdapter>
#include <osgGA/GUIActionAdapter>

namespace osgGA{

/**

CameraManipulator is an abstract base class defining the interface, and a certain
amount of default functionality, for classes which wish to control OSG cameras
in response to GUI events.

*/
class OSGGA_EXPORT CameraManipulator : public GUIEventHandler
{
public:

        /** Attach a camera to the manipulator to be used for specifying view.*/
        virtual void setCamera(osg::Camera*);

        /** Get the attached camera.*/
        virtual const osg::Camera * getCamera() const;

        /** Get the attached camera.*/
        virtual osg::Camera * getCamera();

        /**
        Attach a node to the manipulator, automatically detaching any previously attached node.
        setNode(NULL) detaches previous nodes.
        May be ignored by manipulators which do not require a reference model.
        */
        virtual void setNode(osg::Node*) {}

        /** Return const node if attached.*/
        virtual const osg::Node* getNode() const { return NULL; }

        /** Return node if attached.*/
        virtual osg::Node* getNode() { return NULL; }

        /**
        Move the camera to the default position. 
        May be ignored by manipulators if home functionality is not appropriate.
        */
        virtual void home(const GUIEventAdapter& ,GUIActionAdapter&) {}

        /**
        Start/restart the manipulator.
        FIXME: what does this actually mean? Provide examples.
        */
        virtual void init(const GUIEventAdapter& ,GUIActionAdapter&) {}

        /** Handle events, return true if handled, false otherwise. */
        virtual bool handle(const GUIEventAdapter& ea,GUIActionAdapter& us);

        /** Handle visitations */
        virtual void accept(GUIEventHandlerVisitor& v)    { v.visit(*this); }

protected:

        CameraManipulator();
        virtual ~CameraManipulator();

        // Reference pointer to a camera
        osg::ref_ptr<osg::Camera>        _camera;

};

}

#endif