/* -*-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>

namespace osg {

// forward declare
class State;
class AttributeDispatchMap;

struct AttributeDispatch : public osg::Referenced
{
    virtual void assign(const GLvoid*) {}
    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);

        void reset();

        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(osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), vertexDispatcher(array)); }
        void activateColorArray(osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), colorDispatcher(array)); }
        void activateNormalArray(osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), normalDispatcher(array)); }
        void activateSecondaryColorArray(osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), secondaryColorDispatcher(array)); }
        void activateFogCoordArray(osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), fogCoordDispatcher(array)); }
        void activateTexCoordArray(unsigned int unit, osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), texCoordDispatcher(unit, array)); }
        void activateVertexAttribArray(unsigned int unit, osg::Array* array) { if (array && array->getBinding()>osg::Array::BIND_OFF) activate(array->getBinding(), vertexAttribDispatcher(unit, array)); }

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

        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(); }

    protected:

        void init();

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

        bool                  _initialized;
        State*                _state;

        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;
};

}

#endif