/****************************************************************************
* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
*                                                                _   O  _   *
* Copyright(C) 2004-2016                                           \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
*                                                                    \      *
* All rights reserved.                                                      *
*                                                                           *
* This program is free software; you can redistribute it and/or modify      *
* it under the terms of the GNU General Public License as published by      *
* the Free Software Foundation; either version 2 of the License, or         *
* (at your option) any later version.                                       *
*                                                                           *
* This program 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             *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
* for more details.                                                         *
*                                                                           *
****************************************************************************/
/*! \file refine_loop.h
 *
 * \brief This file contain code for Loop's subdivision scheme for triangular
 * mesh and some similar method.
 *
 */

#ifndef __VCGLIB_REFINE_LOOP
#define __VCGLIB_REFINE_LOOP

#include <cmath>
#include <vcg/space/point3.h>
#include <vcg/complex/complex.h>
#include <vcg/complex/algorithms/refine.h>
#include <vcg/complex/algorithms/update/color.h>


namespace vcg{
namespace tri{

/*
Metodo di Loop dalla documentazione "Siggraph 2000 course on subdivision"

        d4------d3							d4------d3
     /	\		 / 	\						 /	\		 / 	\							u
    /		 \  /  	 \					/		e4--e3 	 \					 / \
 /	   	\/	 		\				 /	 / 	\/	\		\					/		\
d5------d1------d2	->	d5--e5--d1--e2--d2			 l--M--r
 \	   	/\	 		/				 \	 \ 	/\	/		/				  \	  /
    \		 /  \ 	 /					\		e6--e7	 /					 \ /
     \	/		 \ 	/						 \	/		 \ 	/							d
        d6------d7							d6------d7

*******************************************************

*/

/*!
 * \brief Weight class for classical Loop's scheme.
 *
 * See Zorin, D. & Schröeder, P.: Subdivision for modeling and animation. Proc. ACM SIGGRAPH [Courses], 2000
 */
template<class SCALAR_TYPE>
struct LoopWeight {
    inline SCALAR_TYPE beta(int k) {
        return (k>3)?(5.0/8.0 - std::pow((3.0/8.0 + std::cos(2.0*M_PI/SCALAR_TYPE(k))/4.0),2))/SCALAR_TYPE(k):3.0/16.0;
    }

    inline SCALAR_TYPE incidentRegular(int) {
        return 3.0/8.0;
    }
    inline SCALAR_TYPE incidentIrregular(int) {
        return 3.0/8.0;
    }
    inline SCALAR_TYPE opposite(int) {
        return 1.0/8.0;
    }
};

/*!
 * \brief Modified Loop's weight to optimise continuity.
 *
 * See Barthe, L. & Kobbelt, L.: Subdivision scheme tuning around extraordinary vertices. Computer Aided Geometric Design, 2004, 21, 561-583
 */
template<class SCALAR_TYPE>
struct RegularLoopWeight {
    inline SCALAR_TYPE beta(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .32517,
                .49954,
                .59549,
                .625,
                .63873,
                .64643,
                .65127,
                .67358,
                .68678,
                .69908
        };

        return (k<=12)?(1.0-bkPolar[k-3])/k:LoopWeight<SCALAR_TYPE>().beta(k);
    }

    inline SCALAR_TYPE incidentRegular(int k) {
        return 1.0 - incidentIrregular(k) - opposite(k)*2;
    }
    inline SCALAR_TYPE incidentIrregular(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .15658,
                .25029,
                .34547,
                .375,
                .38877,
                .39644,
                .40132,
                .42198,
                .43423,
                .44579
        };

        return (k<=12)?bkPolar[k-3]:LoopWeight<SCALAR_TYPE>().incidentIrregular(k);
    }
    inline SCALAR_TYPE opposite(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .14427,
                .12524,
                .11182,
                .125,
                .14771,
                .1768,
                .21092,
                .20354,
                .20505,
                .19828
        };

        return (k<=12)?bkPolar[k-3]:LoopWeight<SCALAR_TYPE>().opposite(k);
    }
};

template<class SCALAR_TYPE>
struct ContinuityLoopWeight {
    inline SCALAR_TYPE beta(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .32517,
                .50033,
                .59464,
                .625,
                .63903,
                .67821,
                .6866,
                .69248,
                .69678,
                .70014
        };

        return (k<=12)?(1.0-bkPolar[k-3])/k:LoopWeight<SCALAR_TYPE>().beta(k);
    }

    inline SCALAR_TYPE incidentRegular(int k) {
        return 1.0 - incidentIrregular(k) - opposite(k)*2;
    }
    inline SCALAR_TYPE incidentIrregular(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .15658,
                .26721,
                .33539,
                .375,
                .36909,
                .25579,
                .2521,
                .24926,
                .24706,
                .2452
        };

        return (k<=12)?bkPolar[k-3]:LoopWeight<SCALAR_TYPE>().incidentIrregular(k);
    }
    inline SCALAR_TYPE opposite(int k) {
        static SCALAR_TYPE bkPolar[] = {
                .14427,
                .12495,
                .11252,
                .125,
                .14673,
                .16074,
                .18939,
                .2222,
                .25894,
                .29934
        };

        return (k<=12)?bkPolar[k-3]:LoopWeight<SCALAR_TYPE>().opposite(k);
    }
};

// Centroid and LS3Projection classes may be pettre placed in an other file. (which one ?)

/*!
 * \brief Allow to compute classical Loop subdivision surface with the same code than LS3.
 */
template<class MESH_TYPE, class LSCALAR_TYPE = typename MESH_TYPE::ScalarType>
struct Centroid {
    typedef typename MESH_TYPE::ScalarType Scalar;
    typedef typename MESH_TYPE::CoordType CoordType;
    typedef LSCALAR_TYPE LScalar;
    typedef vcg::Point3<LScalar> LVector;

    LVector sumP;
    LScalar sumW;

    Centroid() { reset(); }
    inline void reset() {
        sumP.SetZero();
        sumW = 0.;
    }
    inline void addVertex(const typename MESH_TYPE::VertexType &v, LScalar w) {
        LVector p(v.cP().X(), v.cP().Y(), v.cP().Z());
        sumP += p * w;
        sumW += w;
    }
    inline void project(std::pair<CoordType,CoordType> &nv) const {
        LVector position = sumP / sumW;
        nv.first = CoordType(position.X(), position.Y(), position.Z());
    }
};

/*! Implementation of the APSS projection for the LS3 scheme.
 *
 * See Gael Guennebaud and Marcel Germann and Markus Gross
 * 		Dynamic sampling and rendering of algebraic point set surfaces.
 * 		Computer Graphics Forum (Proceedings of Eurographics 2008), 2008, 27, 653-662
 * and Simon Boye and Gael Guennebaud and Christophe Schlick
 * 		Least squares subdivision surfaces
 * 		Computer Graphics Forum, 2010
 */
template<class MESH_TYPE, class LSCALAR_TYPE = typename MESH_TYPE::ScalarType>
struct LS3Projection {
    typedef typename MESH_TYPE::ScalarType Scalar;
    typedef typename MESH_TYPE::CoordType CoordType;
    typedef LSCALAR_TYPE LScalar;
    typedef vcg::Point3<LScalar> LVector;

    Scalar beta;

    LVector sumP;
    LVector sumN;
    LScalar sumDotPN;
    LScalar sumDotPP;
    LScalar sumW;

    inline LS3Projection(Scalar beta = 1.0) : beta(beta) { reset(); }
    inline void reset() {
        sumP.SetZero();
        sumN.SetZero();
        sumDotPN = 0.;
        sumDotPP = 0.;
        sumW = 0.;
    }
    inline void addVertex(const typename MESH_TYPE::VertexType &v, LScalar w) {
        LVector p(v.cP().X(), v.cP().Y(), v.cP().Z());
        LVector n(v.cN().X(), v.cN().Y(), v.cN().Z());

        sumP += p * w;
        sumN += n * w;
        sumDotPN += w * n.dot(p);
        sumDotPP += w * vcg::SquaredNorm(p);
        sumW += w;
    }
    void project(std::pair<CoordType,CoordType>  &nv) const {
        LScalar invSumW = Scalar(1)/sumW;
        LScalar aux4 = beta * LScalar(0.5) *
                                    (sumDotPN - invSumW*sumP.dot(sumN))
                                    /(sumDotPP - invSumW*vcg::SquaredNorm(sumP));
        LVector uLinear = (sumN-sumP*(Scalar(2)*aux4))*invSumW;
        LScalar uConstant = -invSumW*(uLinear.dot(sumP) + sumDotPP*aux4);
        LScalar uQuad = aux4;
        LVector orig = sumP*invSumW;

        // finalize
        LVector position;
        LVector normal;
        if (fabs(uQuad)>1e-7)
        {
            LScalar b = 1./uQuad;
            LVector center = uLinear*(-0.5*b);
            LScalar radius = sqrt( vcg::SquaredNorm(center) - b*uConstant );

            normal = orig - center;
            normal.Normalize();
            position = center + normal * radius;

            normal = uLinear + position * (LScalar(2) * uQuad);
            normal.Normalize();
        }
        else if (uQuad==0.)
        {
            LScalar s = LScalar(1)/vcg::Norm(uLinear);
            assert(!vcg::math::IsNAN(s) && "normal should not have zero len!");
            uLinear *= s;
            uConstant *= s;

            normal = uLinear;
            position = orig - uLinear * (orig.dot(uLinear) + uConstant);
        }
        else
        {
            // normalize the gradient
            LScalar f = 1./sqrt(vcg::SquaredNorm(uLinear) - Scalar(4)*uConstant*uQuad);
            uConstant *= f;
            uLinear *= f;
            uQuad *= f;

            // Newton iterations
            LVector grad;
            LVector dir = uLinear+orig*(2.*uQuad);
            LScalar ilg = 1./vcg::Norm(dir);
            dir *= ilg;
            LScalar ad = uConstant + uLinear.dot(orig) + uQuad * vcg::SquaredNorm(orig);
            LScalar delta = -ad*std::min<Scalar>(ilg,1.);
            LVector p = orig + dir*delta;
            for (int i=0 ; i<2 ; ++i)
            {
                grad = uLinear+p*(2.*uQuad);
                ilg = 1./vcg::Norm(grad);
                delta = -(uConstant + uLinear.dot(p) + uQuad * vcg::SquaredNorm(p))*std::min<Scalar>(ilg,1.);
                p += dir*delta;
            }
            position = p;

            normal = uLinear + position * (Scalar(2) * uQuad);
            normal.Normalize();
        }

        nv.first = CoordType(position.X(), position.Y(), position.Z());
        nv.second = CoordType(normal.X(), normal.Y(), normal.Z());
    }
};

template<class MESH_TYPE, class METHOD_TYPE=Centroid<MESH_TYPE>, class WEIGHT_TYPE=LoopWeight<typename MESH_TYPE::ScalarType> >
struct OddPointLoopGeneric : public std::unary_function<face::Pos<typename MESH_TYPE::FaceType> , typename MESH_TYPE::VertexType>
{
  typedef METHOD_TYPE Projection;
  typedef WEIGHT_TYPE Weight;
  typedef typename MESH_TYPE::template PerVertexAttributeHandle<int> ValenceAttr;
  typedef typename MESH_TYPE::CoordType CoordType;

    MESH_TYPE &m;
    Projection proj;
    Weight weight;
    ValenceAttr *valence;

    inline OddPointLoopGeneric(MESH_TYPE &_m, Projection proj = Projection(), Weight weight = Weight()) :
        m(_m), proj(proj), weight(weight), valence(0) {}

    void operator()(typename MESH_TYPE::VertexType &nv, face::Pos<typename MESH_TYPE::FaceType>  ep)	{
        proj.reset();

        face::Pos<typename MESH_TYPE::FaceType> he(ep.f,ep.z,ep.f->V(ep.z));
        typename MESH_TYPE::VertexType *l,*r,*u,*d;
        l = he.v;
        he.FlipV();
        r = he.v;

        if( tri::HasPerVertexColor(m))
            nv.C().lerp(ep.f->V(ep.z)->C(),ep.f->V1(ep.z)->C(),.5f);

        if (he.IsBorder()) {
            proj.addVertex(*l, 0.5);
            proj.addVertex(*r, 0.5);
            std::pair<CoordType,CoordType>pp;
            proj.project(pp);
            nv.P()=pp.first;
            nv.N()=pp.second;
        }
        else {
            he.FlipE();	he.FlipV();
            u = he.v;
            he.FlipV();	he.FlipE();
            assert(he.v == r); // back to r
            he.FlipF();	he.FlipE();	he.FlipV();
            d = he.v;

            if(valence && ((*valence)[l]==6 || (*valence)[r]==6)) {
                int extra = ((*valence)[l]==6)?(*valence)[r]:(*valence)[l];
                proj.addVertex(*l, ((*valence)[l]==6)?weight.incidentRegular(extra):weight.incidentIrregular(extra));
                proj.addVertex(*r, ((*valence)[r]==6)?weight.incidentRegular(extra):weight.incidentIrregular(extra));
                proj.addVertex(*u, weight.opposite(extra));
                proj.addVertex(*d, weight.opposite(extra));
            }
            // unhandled case that append only at first subdivision step: use Loop's weights
            else {
                proj.addVertex(*l, 3.0/8.0);
                proj.addVertex(*r, 3.0/8.0);
                proj.addVertex(*u, 1.0/8.0);
                proj.addVertex(*d, 1.0/8.0);
            }
            std::pair<CoordType,CoordType>pp;
            proj.project(pp);
            nv.P()=pp.first;
            nv.N()=pp.second;
//			proj.project(nv);
        }

    }

    Color4<typename MESH_TYPE::ScalarType> WedgeInterp(Color4<typename MESH_TYPE::ScalarType> &c0, Color4<typename MESH_TYPE::ScalarType> &c1)
    {
        Color4<typename MESH_TYPE::ScalarType> cc;
        return cc.lerp(c0,c1,0.5f);
    }

    template<class FL_TYPE>
    TexCoord2<FL_TYPE,1> WedgeInterp(TexCoord2<FL_TYPE,1> &t0, TexCoord2<FL_TYPE,1> &t1)
    {
        TexCoord2<FL_TYPE,1> tmp;
        tmp.n()=t0.n();
        tmp.t()=(t0.t()+t1.t())/2.0;
        return tmp;
    }

    inline void setValenceAttr(ValenceAttr *valence) {
        this->valence = valence;
    }
};

template<class MESH_TYPE, class METHOD_TYPE=Centroid<MESH_TYPE>, class WEIGHT_TYPE=LoopWeight<typename MESH_TYPE::ScalarType> >
struct EvenPointLoopGeneric : public std::unary_function<face::Pos<typename MESH_TYPE::FaceType> , typename MESH_TYPE::VertexType>
{
    typedef METHOD_TYPE Projection;
    typedef WEIGHT_TYPE Weight;
    typedef typename MESH_TYPE::template PerVertexAttributeHandle<int> ValenceAttr;
  typedef typename MESH_TYPE::CoordType CoordType;

    Projection proj;
    Weight weight;
    ValenceAttr *valence;

    inline EvenPointLoopGeneric(Projection proj = Projection(), Weight weight = Weight()) :
        proj(proj), weight(weight), valence(0) {}

    void operator()(std::pair<CoordType,CoordType> &nv, face::Pos<typename MESH_TYPE::FaceType>  ep)	{
        proj.reset();

        face::Pos<typename MESH_TYPE::FaceType> he(ep.f,ep.z,ep.f->V(ep.z));
        typename MESH_TYPE::VertexType *r, *l,  *curr;
        curr = he.v;
        face::Pos<typename MESH_TYPE::FaceType> heStart = he;

        // compute valence of this vertex or find a border
        int k = 0;
        do {
            he.NextE();
            k++;
        }	while(!he.IsBorder() && he != heStart);

        if (he.IsBorder()) {	//	Border rule
            // consider valence of borders as if they are half+1 of an inner vertex. not perfect, but better than nothing.
            if(valence) {
                k = 0;
                do {
                    he.NextE();
                    k++;
                }	while(!he.IsBorder());
                (*valence)[he.V()] = std::max(2*(k-1), 3);
//				(*valence)[he.V()] = 6;
            }

            he.FlipV();
            r = he.v;
            he.FlipV();
            he.NextB();
            l = he.v;

            proj.addVertex(*curr, 3.0/4.0);
            proj.addVertex(*l, 1.0/8.0);
            proj.addVertex(*r, 1.0/8.0);
//			std::pair<Point3f,Point3f>pp;
            proj.project(nv);
//			nv.P()=pp.first;
//			nv.N()=pp.second;
//			proj.project(nv);
        }
        else {	//	Inner rule
//			assert(!he.v->IsB()); border flag no longer updated (useless)
            if(valence)
                (*valence)[he.V()] = k;

            typename MESH_TYPE::ScalarType beta = weight.beta(k);

            proj.addVertex(*curr, 1.0 - (typename MESH_TYPE::ScalarType)(k) * beta);
            do {
                proj.addVertex(*he.VFlip(), beta);
                he.NextE();
            }	while(he != heStart);

            proj.project(nv);
        }
    } // end of operator()

    Color4<typename MESH_TYPE::ScalarType> WedgeInterp(Color4<typename MESH_TYPE::ScalarType> &c0, Color4<typename MESH_TYPE::ScalarType> &c1)
    {
        Color4<typename MESH_TYPE::ScalarType> cc;
        return cc.lerp(c0,c1,0.5f);
    }
    Color4b WedgeInterp(Color4b &c0, Color4b &c1)
    {
        Color4b cc;
        cc.lerp(c0,c1,0.5f);
        return cc;
    }

    template<class FL_TYPE>
    TexCoord2<FL_TYPE,1> WedgeInterp(TexCoord2<FL_TYPE,1> &t0, TexCoord2<FL_TYPE,1> &t1)
    {
        TexCoord2<FL_TYPE,1> tmp;
        // assert(t0.n()== t1.n());
        tmp.n()=t0.n();
        tmp.t()=(t0.t()+t1.t())/2.0;
        return tmp;
    }

    inline void setValenceAttr(ValenceAttr *valence) {
        this->valence = valence;
    }
};

template<class MESH_TYPE>
struct OddPointLoop : OddPointLoopGeneric<MESH_TYPE, Centroid<MESH_TYPE> >
{
  OddPointLoop(MESH_TYPE &_m):OddPointLoopGeneric<MESH_TYPE, Centroid<MESH_TYPE> >(_m){}
};

template<class MESH_TYPE>
struct EvenPointLoop : EvenPointLoopGeneric<MESH_TYPE, Centroid<MESH_TYPE> >
{
};

template<class MESH_TYPE,class ODD_VERT, class EVEN_VERT>
bool RefineOddEven(MESH_TYPE &m, ODD_VERT odd, EVEN_VERT even,float length,
                    bool RefineSelected=false, CallBackPos *cbOdd = 0, CallBackPos *cbEven = 0)
{
  EdgeLen <MESH_TYPE, typename MESH_TYPE::ScalarType> ep(length);
  return RefineOddEvenE(m, odd, even, ep, RefineSelected, cbOdd, cbEven);
}

/*!
 * \brief Perform diadic subdivision using given rules for odd and even vertices.
 */
template<class MESH_TYPE, class ODD_VERT, class EVEN_VERT, class PREDICATE>
bool RefineOddEvenE(MESH_TYPE &m, ODD_VERT odd, EVEN_VERT even, PREDICATE edgePred,
                                        bool RefineSelected=false, CallBackPos *cbOdd = 0, CallBackPos *cbEven = 0)
{
    typedef typename MESH_TYPE::template PerVertexAttributeHandle<int> ValenceAttr;

    // momentaneamente le callback sono identiche, almeno cbOdd deve essere passata
    cbEven = cbOdd;

    // to mark visited vertices
    int evenFlag = MESH_TYPE::VertexType::NewBitFlag();
    for (int i = 0; i < m.vn ; i++ ) {
        m.vert[i].ClearUserBit(evenFlag);
    }

    int j = 0;
    // di texture per wedge (uno per ogni edge)

  ValenceAttr valence = vcg::tri::Allocator<MESH_TYPE>:: template AddPerVertexAttribute<int>(m);
    odd.setValenceAttr(&valence);
    even.setValenceAttr(&valence);

    // store updated vertices
    std::vector<bool> updatedList(m.vn, false);
    //std::vector<typename MESH_TYPE::VertexType> newEven(m.vn);
    std::vector<std::pair<typename MESH_TYPE::CoordType, typename MESH_TYPE::CoordType> > newEven(m.vn);

    typename MESH_TYPE::VertexIterator vi;
    typename MESH_TYPE::FaceIterator fi;
    for (fi = m.face.begin(); fi != m.face.end(); fi++) if(!(*fi).IsD() && (!RefineSelected || (*fi).IsS())){ //itero facce
        for (int i = 0; i < 3; i++) { //itero vert
            if ( !(*fi).V(i)->IsUserBit(evenFlag) && ! (*fi).V(i)->IsD() ) {
                (*fi).V(i)->SetUserBit(evenFlag);
                //	use face selection, not vertex selection, to be coherent with RefineE
                //if (RefineSelected && !(*fi).V(i)->IsS() )
                //	break;
                face::Pos<typename MESH_TYPE::FaceType>aux (&(*fi),i);
                if( tri::HasPerVertexColor(m) ) {
                    (*fi).V(i)->C().lerp((*fi).V0(i)->C() , (*fi).V1(i)->C(),0.5f);
                }

                if (cbEven) {
                    (*cbEven)(int(100.0f * (float)j / (float)m.fn),"Refining");
                    j++;
                }
                int index = tri::Index(m, (*fi).V(i));
                updatedList[index] = true;
                even(newEven[index], aux);
            }
        }
    }

    MESH_TYPE::VertexType::DeleteBitFlag(evenFlag);

    // Now apply the stored normal and position to the initial vertex set (note that newEven is << m.vert)
    RefineE< MESH_TYPE, ODD_VERT > (m, odd, edgePred, RefineSelected, cbOdd);
    for(size_t i=0;i<newEven.size();++i) {
            if(updatedList[i]) {
              m.vert[i].P()=newEven[i].first;
              m.vert[i].N()=newEven[i].second;
        }
    }

    odd.setValenceAttr(0);
    even.setValenceAttr(0);

  vcg::tri::Allocator<MESH_TYPE>::DeletePerVertexAttribute(m, valence);

    return true;
}

} // namespace tri
} // namespace vcg




#endif