/* -*-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_ArrayDispatchers
#define OSG_ArrayDispatchers 1

#include <osg/ref_ptr>
#include <osg/Array>
#include <osg/Matrixd>
#include <osg/GLBeginEndAdapter>

namespace osg {

// forward declare
class State;
class AttributeDispatchMap;

struct AttributeDispatch : public osg::Referenced
{
    virtual void assign(const GLvoid*, const IndexArray*) {}
    virtual void operator() (unsigned int) {};
};

/** Helper class for managing the dispatch to OpenGL of various attribute arrays such as stored in osg::Geometry.*/
class OSG_EXPORT ArrayDispatchers : public osg::Referenced
{
    public:

        ArrayDispatchers();
        ~ArrayDispatchers();

        void setState(osg::State* state);

        AttributeDispatch* vertexDispatcher(Array* array, IndexArray* indices);
        AttributeDispatch* normalDispatcher(Array* array, IndexArray* indices);
        AttributeDispatch* colorDispatcher(Array* array, IndexArray* indices);
        AttributeDispatch* secondaryColorDispatcher(Array* array, IndexArray* indices);
        AttributeDispatch* fogCoordDispatcher(Array* array, IndexArray* indices);
        AttributeDispatch* texCoordDispatcher(unsigned int unit, Array* array, IndexArray* indices);
        AttributeDispatch* vertexAttribDispatcher(unsigned int unit, Array* array, IndexArray* indices);

        void reset();

        void setUseGLBeginEndAdapter(bool flag) { _useGLBeginEndAdapter = flag; }
        bool getUseGLBeginEndAdapter() const { return _useGLBeginEndAdapter; }

        void setUseVertexAttribAlias(bool flag) { _useVertexAttribAlias = flag; }
        bool getUseVertexAttribAlias() const { return _useVertexAttribAlias; }

        void activate(unsigned int binding, AttributeDispatch* at)
        {
            if (at) _activeDispatchList[binding].push_back(at);
        }

        void activateVertexArray(unsigned int binding, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, vertexDispatcher(array, indices)); }
        void activateColorArray(unsigned int binding, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, colorDispatcher(array, indices)); }
        void activateNormalArray(unsigned int binding, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, normalDispatcher(array, indices)); }
        void activateSecondaryColorArray(unsigned int binding, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, secondaryColorDispatcher(array, indices)); }
        void activateFogCoordArray(unsigned int binding, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, fogCoordDispatcher(array, indices)); }
        void activateTexCoordArray(unsigned int binding, unsigned int unit, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, texCoordDispatcher(unit, array, indices)); }
        void activateVertexAttribArray(unsigned int binding, unsigned int unit, osg::Array* array, osg::IndexArray* indices) { if (binding && array) activate(binding, vertexAttribDispatcher(unit, array, indices)); }

        void dispatch(unsigned int binding, unsigned int index)
        {
            AttributeDispatchList& ad = _activeDispatchList[binding];
            for(AttributeDispatchList::iterator itr = ad.begin();
                itr != ad.end();
                ++itr)
            {
                (*(*itr))(index);
            }
        }

        bool active(unsigned int binding) const { return !_activeDispatchList[binding].empty(); }

        void Begin(GLenum mode)
        {
#ifdef OSG_GL1_AVAILABLE
            if (_useGLBeginEndAdapter) _glBeginEndAdapter->Begin(mode);
            else ::glBegin(mode);
#else
            _glBeginEndAdapter->Begin(mode);
#endif
        }

        void End()
        {
#ifdef OSG_GL1_AVAILABLE
            if (_useGLBeginEndAdapter) _glBeginEndAdapter->End();
            else ::glEnd();
#else
            _glBeginEndAdapter->End();
#endif
        }

    protected:

        void init();

        void assignTexCoordDispatchers(unsigned int unit);
        void assignVertexAttribDispatchers(unsigned int unit);

        bool                  _initialized;
        State*                _state;
        GLBeginEndAdapter*    _glBeginEndAdapter;

        AttributeDispatchMap* _vertexDispatchers;
        AttributeDispatchMap* _normalDispatchers;
        AttributeDispatchMap* _colorDispatchers;
        AttributeDispatchMap* _secondaryColorDispatchers;
        AttributeDispatchMap* _fogCoordDispatchers;

        typedef std::vector<AttributeDispatchMap*> AttributeDispatchMapList;
        AttributeDispatchMapList _texCoordDispatchers;
        AttributeDispatchMapList _vertexAttribDispatchers;

        typedef std::vector<AttributeDispatch*> AttributeDispatchList;

        typedef std::vector<AttributeDispatchList> ActiveDispatchList;
        ActiveDispatchList    _activeDispatchList;

        bool                    _useVertexAttribAlias;
        bool                    _useGLBeginEndAdapter;
};

}

#endif