/* -*-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_GRAPHICSTHREAD
#define OSG_GRAPHICSTHREAD 1

#include <osg/OperationThread>
#include <osg/State>

namespace osg {

class GraphicsContext;

/** GraphicsThread is a helper class for running OpenGL GraphicsOperation within a single thread assigned to a specific GraphicsContext.*/
class OSG_EXPORT GraphicsThread : public osg::OperationThread
{
    public:

        GraphicsThread();

        /** Run does the graphics thread run loop.*/
        virtual void run();
};

struct OSG_EXPORT GraphicsOperation : public Operation
{
    GraphicsOperation(const std::string& name, bool keep):
        Operation(name,keep) {}

    /** Override the standard Operation operator and dynamic cast object to a GraphicsContext,
      * on success call operation()(GraphicsContext*).*/
    virtual void operator () (Object* object);

    virtual void operator () (GraphicsContext* context) = 0;

    /** Resize any per context GLObject buffers to specified size. */
    virtual void resizeGLObjectBuffers(unsigned int /*maxSize*/) {}

    /** If State is non-zero, this function releases any associated OpenGL objects for
        * the specified graphics context. Otherwise, releases OpenGL objects
        * for all graphics contexts. */
    virtual void releaseGLObjects(osg::State* = 0) const {}
};


/** SwapBufferOperation calls swap buffers on the GraphicsContext.*/
struct OSG_EXPORT SwapBuffersOperation : public GraphicsOperation
{
    SwapBuffersOperation():
        osg::Referenced(true),
        GraphicsOperation("SwapBuffers",true) {}

    virtual void operator () (GraphicsContext* context);
};

/** BarrierOperation allows one to synchronize multiple GraphicsThreads with each other.*/
struct OSG_EXPORT BarrierOperation : public Operation, public OpenThreads::Barrier
{
    enum PreBlockOp
    {
        NO_OPERATION,
        GL_FLUSH,
        GL_FINISH
    };

    BarrierOperation(int numThreads, PreBlockOp op=NO_OPERATION, bool keep=true):
        osg::Referenced(true),
        Operation("Barrier", keep),
        OpenThreads::Barrier(numThreads),
        _preBlockOp(op) {}

    virtual void release();

    virtual void operator () (Object* object);

    PreBlockOp _preBlockOp;
};

/** ReleaseContext_Block_MakeCurrentOperation releases the context for another thread to acquire,
  * then blocks waiting for context to be released, once the block is release the context is re-acquired.*/
struct OSG_EXPORT ReleaseContext_Block_MakeCurrentOperation : public GraphicsOperation, public RefBlock
{
    ReleaseContext_Block_MakeCurrentOperation():
        osg::Referenced(true),
        GraphicsOperation("ReleaseContext_Block_MakeCurrent", false) {}

    virtual void release();

    virtual void operator () (GraphicsContext* context);
};

struct OSG_EXPORT BlockAndFlushOperation : public GraphicsOperation, public OpenThreads::Block
{
    BlockAndFlushOperation();

    virtual void release();

    virtual void operator () (GraphicsContext*);
};


struct OSG_EXPORT FlushDeletedGLObjectsOperation : public GraphicsOperation
{
    FlushDeletedGLObjectsOperation(double availableTime, bool keep=false);

    virtual void operator () (GraphicsContext*);

    double _availableTime;
};

class OSG_EXPORT RunOperations : public osg::GraphicsOperation
{
public:

    RunOperations():
        osg::GraphicsOperation("RunOperation",true) {}

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

};

class OSG_EXPORT EndOfDynamicDrawBlock : public OpenThreads::BlockCount, public osg::State::DynamicObjectRenderingCompletedCallback
{
    public:

        EndOfDynamicDrawBlock(unsigned int);

        void completed(osg::State* state);

    protected:

        ~EndOfDynamicDrawBlock() {}
};

}

#endif
