/* -*-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_VERTEXATTRIBDIVISOR
#define OSG_VERTEXATTRIBDIVISOR 1

#include <osg/StateAttribute>
#include <osg/Vec3>
#include <osg/Vec4>

namespace osg {

/** VertexAttribDivisor state class which encapsulates OpenGL glVertexAttribDivisor() functionality. */
class OSG_EXPORT VertexAttribDivisor : public StateAttribute
{
    public :

        VertexAttribDivisor();

        VertexAttribDivisor(unsigned int index, unsigned int divisor);

        /** Copy constructor using CopyOp to manage deep vs shallow copy. */
        VertexAttribDivisor(const VertexAttribDivisor& vad,const CopyOp& copyop=CopyOp::SHALLOW_COPY):
            StateAttribute(vad,copyop),
            _index(vad._index),
            _divisor(vad._divisor) {}

        virtual osg::Object* cloneType() const { return new VertexAttribDivisor(_index, 0); }
        virtual osg::Object* clone(const osg::CopyOp& copyop) const { return new VertexAttribDivisor(*this,copyop); }
        virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const VertexAttribDivisor *>(obj)!=NULL; }
        virtual const char* libraryName() const { return "osg"; }
        virtual const char* className() const { return "VertexAttribDivisor"; }
        virtual Type getType() const { return VERTEX_ATTRIB_DIVISOR; }

        /** Return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs. */
        virtual int compare(const StateAttribute& sa) const
        {
            // check the types are equal and then create the rhs variable
            // used by the COMPARE_StateAttribute_Parameter macros below.
            COMPARE_StateAttribute_Types(VertexAttribDivisor,sa)

            // compare each parameter in turn against the rhs.
            COMPARE_StateAttribute_Parameter(_index)
            COMPARE_StateAttribute_Parameter(_divisor)

            return 0; // passed all the above comparison macros, must be equal.
        }

        virtual unsigned int getMember() const { return _index; }


        /** Set the vertex attrib index - the vertex attribute slot that the divisor should apply to. */
        inline void setIndex( unsigned int index )                       { _index = index; }

        /** Get the vertex attrib index. */
        inline unsigned int getIndex() const                               { return _index; }

        /** Set the vertex attrib divisor. */
        inline void setDivisor( unsigned int divisor )                       { _divisor = divisor; }

        /** Get the vertex attrib divisor. */
        inline unsigned int getDivisor() const                               { return _divisor; }

        /** Apply to the OpenGL state machine. */
        virtual void apply(State& state) const;

    protected :

        virtual ~VertexAttribDivisor();

        unsigned int _index;
        unsigned int _divisor;
};

}

#endif
