/* -*-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_VertexArrayState
#define OSG_VertexArrayState 1

#include <osg/Referenced>
#include <osg/GLExtensions>
#include <osg/Array>
#include <osg/AttributeDispatchers>

namespace osg {

class OSG_EXPORT VertexArrayState : public osg::Referenced
{
public:

        VertexArrayState(osg::State* state);

        struct ArrayDispatch : public osg::Referenced
        {
            ArrayDispatch():
                array(0),
                modifiedCount(0xffffffff),
                active(false) {}

            virtual void enable_and_dispatch(osg::State& /*state*/, const osg::Array* /*new_array*/) {} // = 0;

            virtual void enable_and_dispatch(osg::State& /*state*/, const osg::Array* /*new_array*/, const osg::GLBufferObject* /*vbo*/) {} // = 0;

            virtual void enable_and_dispatch(osg::State& /*state*/, GLint /*size*/, GLenum /*type*/, GLsizei /*stride*/, const GLvoid * /*ptr*/, GLboolean /*normalized*/) {} // = 0;

            virtual void dispatch(osg::State& /*state*/, const osg::Array* /*new_array*/) {} // = 0;

            virtual void dispatch(osg::State& /*state*/, const osg::Array* /*new_array*/, const osg::GLBufferObject* /*vbo*/) {} // = 0;

            virtual void dispatch(osg::State& /*state*/, GLint /*size*/, GLenum /*type*/, GLsizei /*stride*/, const GLvoid * /*ptr*/, GLboolean /*normalized*/) {} // = 0;

            virtual void disable(osg::State& /*state*/) {} // = 0;

            const osg::Array*   array;
            unsigned int        modifiedCount;
            bool                active;
        };

        typedef std::vector< ref_ptr<ArrayDispatch> >       ArrayDispatchList;

        void setCurrentVertexBufferObject(osg::GLBufferObject* vbo) { _currentVBO = vbo; }
        GLBufferObject* getCurrentVertexBufferObject() { return _currentVBO; }

        inline void bindVertexBufferObject(osg::GLBufferObject* vbo)
        {
            if (vbo->isDirty())
            {
                vbo->compileBuffer();
                _currentVBO = vbo;
            }
            else if (vbo != _currentVBO)
            {
                vbo->bindBuffer();
                _currentVBO = vbo;
            }
        }

        inline void unbindVertexBufferObject()
        {
            if (!_currentVBO) return;
            _ext->glBindBuffer(GL_ARRAY_BUFFER_ARB,0);
            _currentVBO = 0;
        }


        void setCurrentElementBufferObject(osg::GLBufferObject* ebo) { _currentEBO = ebo; }
        GLBufferObject* getCurrentElementBufferObject() { return _currentEBO; }

        inline void bindElementBufferObject(osg::GLBufferObject* ebo)
        {
            if (ebo->isDirty())
            {
                ebo->compileBuffer();
                _currentEBO = ebo;
            }
            else if (ebo != _currentEBO)
            {
                ebo->bindBuffer();
                _currentEBO = ebo;
            }
        }

        inline void unbindElementBufferObject()
        {
            if (!_currentEBO) return;
            _ext->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER_ARB,0);
            _currentEBO = 0;
        }

        void resetBufferObjectPointers() { _currentVBO = 0; _currentEBO = 0; }

        void assignAllDispatchers();

        void assignVertexArrayDispatcher();
        void assignNormalArrayDispatcher();
        void assignColorArrayDispatcher();
        void assignSecondaryColorArrayDispatcher();
        void assignFogCoordArrayDispatcher();
        void assignTexCoordArrayDispatcher(unsigned int numUnits);
        void assignVertexAttribArrayDispatcher(unsigned int numUnits);

        inline void setVertexBufferObjectSupported(bool flag) { _isVertexBufferObjectSupported = flag; }
        inline bool isVertexBufferObjectSupported() const { return _isVertexBufferObjectSupported; }

        void setArray(ArrayDispatch* vad, osg::State& state, const osg::Array* new_array);
        void setArray(ArrayDispatch* vad, osg::State& state, GLint size, GLenum type, GLsizei stride, const GLvoid *ptr, GLboolean normalized);

        inline void disable(ArrayDispatch* vad, osg::State& state) { vad->disable(state); vad->array=0; vad->modifiedCount=0xffffffff; vad->active=false; }

        void setInterleavedArrays( osg::State& state, GLenum format, GLsizei stride, const GLvoid* pointer);

        inline void setVertexArray(osg::State& state, const osg::Array* array) { setArray(_vertexArray.get(), state, array); }
        inline void setVertexArray(osg::State& state, GLint size, GLenum type, GLsizei stride, const GLvoid *ptr, GLboolean normalized=GL_FALSE) { setArray(_vertexArray.get(), state, size, type, stride, ptr, normalized); }
        inline void disableVertexArray(osg::State& state) { disable(_vertexArray.get(), state); }

        inline void setNormalArray(osg::State& state, const osg::Array* array) { setArray(_normalArray.get(), state, array); }
        inline void setNormalArray(osg::State& state, GLenum type, GLsizei stride, const GLvoid *ptr, GLboolean normalized=GL_FALSE ) { setArray(_normalArray.get(), state, 3, type, stride, ptr, normalized); }
        inline void disableNormalArray(osg::State& state) { disable(_normalArray.get(), state); }

        inline void setColorArray(osg::State& state, const osg::Array* array) { setArray(_colorArray.get(), state, array); }
        inline void setColorArray(osg::State& state, GLint size, GLenum type, GLsizei stride, const GLvoid *ptr, GLboolean normalized=GL_TRUE ) { setArray(_colorArray.get(), state, size, type, stride, ptr, normalized); }
        inline void disableColorArray(osg::State& state) { disable(_colorArray.get(), state); }

        inline void setSecondaryColorArray(osg::State& state, const osg::Array* array) { setArray(_secondaryColorArray.get(), state, array); }
        inline void disableSecondaryColorArray(osg::State& state) { disable(_secondaryColorArray.get(), state); }

        inline void setFogCoordArray(osg::State& state, const osg::Array* array) { setArray(_fogCoordArray.get(), state, array); }
        inline void disableFogCoordArray(osg::State& state) { disable(_fogCoordArray.get(), state); }

        inline void setTexCoordArray(osg::State& state, unsigned int unit, const osg::Array* array) { setArray(_texCoordArrays[unit].get(), state, array); }
        inline void setTexCoordArray(osg::State& state, unsigned int unit, GLint size, GLenum type, GLsizei stride, const GLvoid *ptr, GLboolean normalized=GL_FALSE ) { setArray(_texCoordArrays[unit].get(), state, size, type, stride, ptr, normalized); }
        inline void disableTexCoordArray(osg::State& state, unsigned int unit) { disable(_texCoordArrays[unit].get(),state); }
        inline void disableTexCoordArrayAboveAndIncluding(osg::State& state, unsigned int index);

        inline void setVertexAttribArray(osg::State& state, unsigned int unit, const osg::Array* array) { setArray(_vertexAttribArrays[unit].get(), state, array); }
        inline void disableVertexAttribArray(osg::State& state, unsigned int unit) { disable(_vertexAttribArrays[unit].get(), state); }
        inline void disableVertexAttribArrayAboveAndIncluding(osg::State& state, unsigned int index);

        /** Mark all the vertex attributes as being disabled but leave the disabling till a later call to applyDisablingOfVertexAttributes.*/
        inline void lazyDisablingOfVertexAttributes();

        /** Disable all the vertex attributes that have been marked as to be disabled.*/
        inline void applyDisablingOfVertexAttributes(osg::State& state);

        // Verex Array Object methods.
        void generateVertexArrayObject();

        void deleteVertexArrayObject();

        inline void bindVertexArrayObject() const { _ext->glBindVertexArray (_vertexArrayObject); }

        inline void unbindVertexArrayObject() const { _ext->glBindVertexArray (0); }

        GLuint getVertexArrayObject() const { return _vertexArrayObject; }


        void setRequiresSetArrays(bool flag) { _requiresSetArrays = flag; }
        bool getRequiresSetArrays() const { return _requiresSetArrays; }

        void dirty();

        void release();

public:


        // osg::GLBufferObject* getGLBufferObject(osg::Array* array);

        osg::State*                     _state;
        osg::ref_ptr<osg::GLExtensions> _ext;

        bool                            _isVertexBufferObjectSupported;

        GLuint                          _vertexArrayObject;


        osg::ref_ptr<ArrayDispatch>     _vertexArray;
        osg::ref_ptr<ArrayDispatch>     _normalArray;
        osg::ref_ptr<ArrayDispatch>     _colorArray;
        osg::ref_ptr<ArrayDispatch>     _secondaryColorArray;
        osg::ref_ptr<ArrayDispatch>     _fogCoordArray;
        ArrayDispatchList               _texCoordArrays;
        ArrayDispatchList               _vertexAttribArrays;

        typedef std::vector<ArrayDispatch*> ActiveDispatchers;
        ActiveDispatchers               _activeDispatchers;
        ActiveDispatchers               _previous_activeDispatchers;

        GLBufferObject*                 _currentVBO;
        GLBufferObject*                 _currentEBO;

        bool                            _requiresSetArrays;
};


inline void VertexArrayState::lazyDisablingOfVertexAttributes()
{
    _activeDispatchers.swap(_previous_activeDispatchers);
    _activeDispatchers.clear();

    for(ActiveDispatchers::iterator itr = _previous_activeDispatchers.begin();
        itr != _previous_activeDispatchers.end();
        ++itr)
    {
        ArrayDispatch* ad = (*itr);
        // ad->array = 0;
        ad->active = false;
    }
}

inline void VertexArrayState::applyDisablingOfVertexAttributes(osg::State& state)
{
    for(ActiveDispatchers::iterator itr = _previous_activeDispatchers.begin();
        itr != _previous_activeDispatchers.end();
        ++itr)
    {
        ArrayDispatch* ad = (*itr);
        if (!ad->active)
        {
            ad->disable(state);
            ad->array = 0;
            ad->modifiedCount = 0xffffffff;
        }
    }
    _previous_activeDispatchers.clear();
}

inline void VertexArrayState::disableTexCoordArrayAboveAndIncluding(osg::State& state, unsigned int index)
{
    for(unsigned int i=index; i<_texCoordArrays.size(); ++i)
    {
        disable(_texCoordArrays[i].get(), state);
    }
}

inline void VertexArrayState::disableVertexAttribArrayAboveAndIncluding(osg::State& state, unsigned int index)
{
    for(unsigned int i=index; i<_vertexAttribArrays.size(); ++i)
    {
        disable(_vertexAttribArrays[i].get(), state);
    }
}



}

#endif