/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library 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 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSGVIEWER_RENDERER
#define OSGVIEWER_RENDERER 1

#include <OpenThreads/Condition>
#include <osg/Timer>
#include <osgDB/DatabasePager>
#include <osgUtil/SceneView>
#include <osgViewer/Export>

namespace osgViewer {

class OSGVIEWER_EXPORT OpenGLQuerySupport : public osg::Referenced
{
    public:
        OpenGLQuerySupport();

        virtual void checkQuery(osg::Stats* stats, osg::State* state,
                                osg::Timer_t startTick) = 0;
        
        virtual void beginQuery(unsigned int frameNumber, osg::State* state) = 0;
        virtual void endQuery(osg::State* state) = 0;
        virtual void initialize(osg::State* state, osg::Timer_t startTick);
    protected:

        const osg::Drawable::Extensions*            _extensions;
};

class OSGVIEWER_EXPORT Renderer : public osg::GraphicsOperation
{
    public:

        Renderer(osg::Camera* camera);

        osgUtil::SceneView* getSceneView(unsigned int i) { return _sceneView[i].get(); }
        const osgUtil::SceneView* getSceneView(unsigned int i) const { return _sceneView[i].get(); }

        void setDone(bool done) { _done = done; }
        bool getDone() { return _done; }

        void setGraphicsThreadDoesCull(bool flag);
        bool getGraphicsThreadDoesCull() const { return _graphicsThreadDoesCull; }


        virtual void cull();
        virtual void draw();
        virtual void cull_draw();

        virtual void compile();
        
        void setCompileOnNextDraw(bool flag) { _compileOnNextDraw = flag; }
        bool getCompileOnNextDraw() const { return _compileOnNextDraw; }

        virtual void operator () (osg::Object* object);
        
        virtual void operator () (osg::GraphicsContext* context);

        virtual void release();
        
        /** Force update of state associated with cameras. */
        void setCameraRequiresSetUp(bool flag);
        bool getCameraRequiresSetUp() const;

    protected:
        void initialize(osg::State* state);
        virtual ~Renderer();

        virtual void updateSceneView(osgUtil::SceneView* sceneView);        

        osg::observer_ptr<osg::Camera>                      _camera;
        
        bool                                                _done;
        bool                                                _graphicsThreadDoesCull;
        bool                                                _compileOnNextDraw;
        
        osg::ref_ptr<osgUtil::SceneView>                    _sceneView[2];

        struct OSGVIEWER_EXPORT ThreadSafeQueue
        {
            OpenThreads::Mutex _mutex;
            OpenThreads::Condition _cond;
            typedef std::list<osgUtil::SceneView*> SceneViewList;
            SceneViewList _queue;
            bool _isReleased;
            
            ThreadSafeQueue();
            ~ThreadSafeQueue();

            /** Release any thread waiting on the queue, even if the queue is empty. */
            void release();

            /** Take a SceneView from the queue. Can return 0 if release() is called when the queue is empty. */
            osgUtil::SceneView* takeFront();

            /**  Add a SceneView object to the back of the queue. */
            void add(osgUtil::SceneView* sv);
        };


        ThreadSafeQueue _availableQueue;
        ThreadSafeQueue _drawQueue;

        bool _initialized;
        osg::ref_ptr<OpenGLQuerySupport> _querySupport;
        osg::Timer_t _startTick;
};

}

#endif