/* -*-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_ATTRIBUTEDISPATCHERS
#define OSG_ATTRIBUTEDISPATCHERS 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 AttributeDispatchers : public osg::Referenced
{
    public:

        AttributeDispatchers();
        ~AttributeDispatchers();

        void setState(osg::State* state);

        void reset();

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


        #define DISPATCH_OR_ACTIVATE(array, dispatcher) \
            if (array) { \
                unsigned int binding = array->getBinding(); \
                if (binding==osg::Array::BIND_OVERALL) \
                { \
                    AttributeDispatch* at = dispatcher; \
                    if (at) (*at)(0); \
                } \
                else if (binding==osg::Array::  BIND_PER_PRIMITIVE_SET) \
                { \
                    AttributeDispatch* at = dispatcher; \
                    if (at) _activeDispatchList.push_back(at); \
                } \
            }


        void activateColorArray(osg::Array* array) { DISPATCH_OR_ACTIVATE(array, colorDispatcher(array)); }
        void activateNormalArray(osg::Array* array) { DISPATCH_OR_ACTIVATE(array, normalDispatcher(array)); }
        void activateSecondaryColorArray(osg::Array* array) { DISPATCH_OR_ACTIVATE(array, secondaryColorDispatcher(array)); }
        void activateFogCoordArray(osg::Array* array) { DISPATCH_OR_ACTIVATE(array, fogCoordDispatcher(array)); }
        void activateVertexAttribArray(unsigned int unit, osg::Array* array) { DISPATCH_OR_ACTIVATE(array, vertexAttribDispatcher(unit , array)); }

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

        void dispatch(unsigned int index)
        {
            for(AttributeDispatchList::iterator itr = _activeDispatchList.begin();
                itr != _activeDispatchList.end();
                ++itr)
            {
                (*(*itr))(index);
            }
        }

        bool active() const { return !_activeDispatchList.empty(); }

    protected:

        void init();

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

        bool                  _initialized;
        State*                _state;

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

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

        typedef std::vector<AttributeDispatch*> AttributeDispatchList;

        AttributeDispatchList   _activeDispatchList;

        bool                    _useVertexAttribAlias;
};

}

#endif