/* -*-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 OSG_GLOBJECTS
#define OSG_GLOBJECTS 1

#include <osg/Referenced>
#include <osg/GL>
#include <list>
#include <string>

namespace osg {

// forward declare
class FrameStamp;

/** Flush all deleted OpenGL objects within the specified availableTime.
  * Note, must be called from a thread which has current the graphics context associated with contextID. */
extern OSG_EXPORT void flushDeletedGLObjects(unsigned int contextID, double currentTime, double& availableTime);

/** Flush all deleted OpenGL objects.
  * Note, must be called from a thread which has current the graphics context associated with contextID. */
extern OSG_EXPORT void flushAllDeletedGLObjects(unsigned int contextID);

/** Do a GL delete all OpenGL objects.
  * Note, must be called from a thread which has current the graphics context associated with contextID. */
extern OSG_EXPORT void deleteAllGLObjects(unsigned int contextID);

/** Discard all OpenGL objects.
  * Note, unlike deleteAllGLjects discard does not
  * do any OpenGL calls so can be called from any thread, but as a consequence it
  * also doesn't remove the associated OpenGL resource so discard should only be
  * called when the associated graphics context is being/has been closed. */
extern OSG_EXPORT void discardAllGLObjects(unsigned int contextID);

class OSG_EXPORT GraphicsObject : public osg::Referenced
{
    public:
        GraphicsObject();

    protected:
        virtual ~GraphicsObject();
};


class OSG_EXPORT GraphicsObjectManager : public osg::Referenced
{
    public:
        GraphicsObjectManager(const std::string& name, unsigned int contextID);

        unsigned int getContextID() const { return _contextID; }

        /** Signal that a new frame has started.*/
        virtual void newFrame(osg::FrameStamp* fs) {}

        virtual void resetStats() {}
        virtual void reportStats(std::ostream& out)  {}
        virtual void recomputeStats(std::ostream& out) const  {}


        /** Flush all deleted OpenGL objects within the specified availableTime.
        * Note, must be called from a thread which has current the graphics context associated with contextID. */
        virtual void flushDeletedGLObjects(double currentTime, double& availableTime) = 0;

        /** Flush all deleted OpenGL objects.
        * Note, must be called from a thread which has current the graphics context associated with contextID. */
        virtual void flushAllDeletedGLObjects() = 0;

        /** Do a GL delete all OpenGL objects.
        * Note, must be called from a thread which has current the graphics context associated with contextID. */
        virtual void deleteAllGLObjects() = 0;

        /** Discard all OpenGL objects.
        * Note, unlike deleteAllGLjects discard does not
        * do any OpenGL calls so can be called from any thread, but as a consequence it
        * also doesn't remove the associated OpenGL resource so discard should only be
        * called when the associated graphics context is being/has been closed. */
        virtual void discardAllGLObjects() = 0;

    protected:
        virtual ~GraphicsObjectManager();

        std::string     _name;
        unsigned int    _contextID;

};

class OSG_EXPORT GLObjectManager : public GraphicsObjectManager
{
public:
    GLObjectManager(const std::string& name, unsigned int contextID);

    virtual void flushDeletedGLObjects(double currentTime, double& availableTime);

    virtual void flushAllDeletedGLObjects();

    virtual void deleteAllGLObjects();

    virtual void discardAllGLObjects();

    /** schedule a GL object for deletion by the graphics thread.*/
    virtual void scheduleGLObjectForDeletion(GLuint globj);

    /** implementation of the actual creation of an GL object - subclasses from GLObjectManager must implement the appropriate GL calls.*/
    virtual GLuint createGLObject();

    /** implementation of the actual deletion of an GL object - subclasses from GLObjectManager must implement the appropriate GL calls.*/
    virtual void deleteGLObject(GLuint globj) = 0;

protected:
    virtual ~GLObjectManager();

    typedef std::list<GLuint> GLObjectHandleList;
    OpenThreads::Mutex  _mutex;
    GLObjectHandleList _deleteGLObjectHandles;

};


}

#endif