color.h

/****************************************************************************
* 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.                                                         *
*                                                                           *
****************************************************************************/
 
#ifndef __VCG_TRI_UPDATE_COLOR
#define __VCG_TRI_UPDATE_COLOR
 
#include <math.h>
#include <time.h>
#include <vcg/space/color4.h>
#include <vcg/space/colormap.h>
#include <vcg/math/histogram.h>
#include <vcg/math/perlin_noise.h>
#include <vcg/math/random_generator.h>
#include <vcg/complex/algorithms/clean.h>
#include <vcg/complex/algorithms/stat.h>
 
namespace vcg {
namespace tri {
 
template <class MeshType>
class UpdateColor
{
public:
    typedef typename MeshType::VertexType     VertexType;
    typedef typename MeshType::VertexPointer  VertexPointer;
    typedef typename MeshType::VertexIterator VertexIterator;
    typedef typename MeshType::FaceType       FaceType;
    typedef typename MeshType::FacePointer    FacePointer;
    typedef typename MeshType::FaceIterator   FaceIterator;
    typedef typename MeshType::EdgeIterator   EdgeIterator;
    typedef typename MeshType::TetraType      TetraType;
    typedef typename MeshType::TetraPointer   TetraPointer;
    typedef typename MeshType::TetraIterator  TetraIterator;
 
 
    typedef typename MeshType::ScalarType     ScalarType;
    typedef typename MeshType::CoordType      CoordType;
 
    class ColorAvgInfo
    {
    public:
        unsigned int r = 0;
        unsigned int g = 0;
        unsigned int b = 0;
        unsigned int a = 0;
        int cnt = 0;
    };
 
    static int PerVertexConstant(MeshType &m, Color4b vs=Color4b::White,bool selected=false)
    {
        RequirePerVertexColor(m);
 
        int cnt=0;
        for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
            if(!(*vi).IsD()){
                if(!selected || (*vi).IsS())
                {
                    (*vi).C() = vs;
                    ++cnt;
                }
            }
        return cnt;
    }
 
    static int PerFaceConstant(MeshType &m, Color4b vs=Color4b::White,bool selected=false)
    {
        RequirePerFaceColor(m);
        int cnt=0;
        for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
            if(!(*fi).IsD()){
                if(!selected || (*fi).IsS())
                {
                    (*fi).C() = vs;
                    ++cnt;
                }
            }
        return cnt;
    }
 
    static int PerTetraConstant(MeshType & m, Color4b vs = Color4b::White, bool selected = false)
    {
        RequirePerTetraColor(m);
        int cnt = 0;
        ForEachTetra(m, [&] (TetraType & t) {
            if (!selected || t.IsS())
            {
                t.C() = vs;
                ++cnt;
            }
        });
        return cnt;
    }
 
    static void PerVertexFromTetra(MeshType & m)
    {
        RequirePerTetraColor(m);
        RequirePerVertexColor(m);
 
        ColorAvgInfo csi;
        SimpleTempData<typename MeshType::VertContainer, ColorAvgInfo> TD(m.vert, csi);
 
        ForEachTetra(m, [&] (TetraType & t) {
            for (int i = 0; i < 4; ++i)
            {
                TD[t.V(i)].r += t.C()[0];
                TD[t.V(i)].g += t.C()[1];
                TD[t.V(i)].b += t.C()[2];
                TD[t.V(i)].a += t.C()[3];
                TD[t.V(i)].cnt += 1;
            }
        });
 
        ForEachVertex(m, [&] (VertexType & v) {
            v.C()[0] = TD[v].r / TD[v].cnt;
            v.C()[1] = TD[v].g / TD[v].cnt;
            v.C()[2] = TD[v].b / TD[v].cnt;
            v.C()[3] = TD[v].a / TD[v].cnt;
        });
    }
 
    static void PerVertexFromFace( MeshType &m)
    {
        RequirePerFaceColor(m);
        RequirePerVertexColor(m);
 
        ColorAvgInfo csi;
        SimpleTempData<typename MeshType::VertContainer, ColorAvgInfo> TD(m.vert,csi);
 
        FaceIterator fi;
        for(fi=m.face.begin();fi!=m.face.end();++fi)
            if(!(*fi).IsD())
                for(int j=0;j<3;++j)
                {
                    TD[(*fi).V(j)].r+=(*fi).C()[0];
                    TD[(*fi).V(j)].g+=(*fi).C()[1];
                    TD[(*fi).V(j)].b+=(*fi).C()[2];
                    TD[(*fi).V(j)].a+=(*fi).C()[3];
                    ++TD[(*fi).V(j)].cnt;
                }
 
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi)
            if(!(*vi).IsD() && TD[*vi].cnt>0 )
            {
                (*vi).C()[0] = TD[*vi].r / TD[*vi].cnt;
                (*vi).C()[1] = TD[*vi].g / TD[*vi].cnt;
                (*vi).C()[2] = TD[*vi].b / TD[*vi].cnt;
                (*vi).C()[3] = TD[*vi].a / TD[*vi].cnt;
            }
    }
 
    static void PerFaceFromVertex( MeshType &m)
    {
        RequirePerFaceColor(m);
        RequirePerVertexColor(m);
 
        FaceIterator fi;
        for(fi=m.face.begin();fi!=m.face.end();++fi) if(!(*fi).IsD())
        {
            Color4f avg = (Color4f::Construct((*fi).V(0)->C()) +
                           Color4f::Construct((*fi).V(1)->C()) +
                           Color4f::Construct((*fi).V(2)->C()) )/ 3.0;
            (*fi).C().Import(avg);
        }
    }
 
    static void PerVertexQualityRamp(MeshType &m, ScalarType minq = 0., ScalarType maxq = 0., vcg::ColorMap cmap = vcg::ColorMap::RGB)
    {
        RequirePerVertexQuality(m);
        RequirePerVertexColor(m);
 
        if(minq == maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerVertexQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
            if(!(*vi).IsD()) {
                (*vi).C() = vcg::GetColorMapping((*vi).Q(), minq, maxq, cmap);
            }
    }
 
 
    static void PerVertexQualityRampParula(MeshType &m, ScalarType minq = 0., ScalarType maxq = 0.)
    {
        RequirePerVertexQuality(m);
        RequirePerVertexColor(m);
 
        if(minq == maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerVertexQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(VertexIterator vi = m.vert.begin(); vi != m.vert.end(); ++vi)
            if(!(*vi).IsD())
                (*vi).C().SetColorRampParula(minq, maxq, (*vi).Q());
    }
 
    static void PerTetraQualityRamp(MeshType &m, ScalarType minq = 0., ScalarType maxq = 0., bool selected = false, vcg::ColorMap cmap = vcg::ColorMap::RGB)
    {
        RequirePerTetraColor(m);
        RequirePerTetraQuality(m);
 
        if(minq == maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerTetraQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
 
        ForEachTetra(m, [&] (TetraType & t){
            if (!selected || t.IsS())
                t.C() = vcg::GetColorMapping(t.Q(), minq, maxq, cmap);
        });
    }
    static void PerFaceQualityRamp(MeshType &m, ScalarType minq = 0, ScalarType maxq = 0, bool selected = false, vcg::ColorMap cmap = vcg::ColorMap::RGB)
    {
        RequirePerFaceColor(m);
        RequirePerFaceQuality(m);
 
        if(minq == maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerFaceQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(FaceIterator fi = m.face.begin();fi != m.face.end(); ++fi)
            if(!(*fi).IsD())
                if(!selected || (*fi).IsS())
                    (*fi).C() = vcg::GetColorMapping((*fi).Q(), minq, maxq, cmap);
    }
 
    static void PerEdgeQualityRamp(MeshType &m, ScalarType minq = 0, ScalarType maxq = 0, bool selected = false, vcg::ColorMap cmap = vcg::ColorMap::RGB)
    {
        RequirePerEdgeColor(m);
        RequirePerEdgeQuality(m);
 
        if(minq == maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerEdgeQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(EdgeIterator ei=m.edge.begin();ei!=m.edge.end();++ei) if(!(*ei).IsD())
            if(!selected || (*ei).IsS())
                (*ei).C() = vcg::GetColorMapping((*ei).Q(), minq, maxq, cmap);
    }
 
    static void PerVertexQualityGray(MeshType &m,  ScalarType minq = 0, ScalarType maxq = 0)
    {
        RequirePerVertexColor(m);
        RequirePerVertexQuality(m);
        if(minq==maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerVertexQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
            if(!(*vi).IsD())
                (*vi).C().SetGrayShade( ((*vi).Q()-minq)/(maxq-minq));
    }
 
    static void PerFaceQualityGray(MeshType &m, ScalarType minq = 0, ScalarType maxq = 0)
    {
        RequirePerFaceColor(m);
        RequirePerFaceQuality(m);
 
        if(minq==maxq)
        {
            std::pair<ScalarType, ScalarType> minmax = Stat<MeshType>::ComputePerFaceQualityMinMax(m);
            minq=minmax.first;
            maxq=minmax.second;
        }
        for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi) if(!(*fi).IsD())
            (*fi).C().SetGrayShade( ((*fi).Q()-minq)/(maxq-minq));
    }
 
    static void PerVertexBorderFlag( MeshType &m, Color4b BorderColor=Color4b::Blue, Color4b InternalColor=Color4b::White, Color4b MixColor=Color4b::Cyan)
    {
        RequirePerVertexColor(m);
 
        Color4b BaseColor = Color4b::Green;
 
        PerVertexConstant(m,BaseColor);
        for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi) if(!(*fi).IsD())
            for(int j=0;j<3;++j)
            {
                if((*fi).IsB(j)){
                    if( (*fi).V(j)->C() == BaseColor)     (*fi).V(j)->C() = BorderColor;
                    if( (*fi).V(j)->C() == InternalColor) (*fi).V(j)->C() = MixColor;
                    if( (*fi).V1(j)->C() == BaseColor)     (*fi).V1(j)->C() = BorderColor;
                    if( (*fi).V1(j)->C() == InternalColor) (*fi).V1(j)->C() = MixColor;
                } else
                {
                    if( (*fi).V(j)->C() == BaseColor)     (*fi).V(j)->C() = InternalColor;
                    if( (*fi).V(j)->C() == BorderColor) (*fi).V(j)->C() = MixColor;
                    if( (*fi).V1(j)->C() == BaseColor)     (*fi).V1(j)->C() = InternalColor;
                    if( (*fi).V1(j)->C() == BorderColor) (*fi).V1(j)->C() = MixColor;
                }
            }
 
    }
 
    static void PerFaceRandomConnectedComponent( MeshType &m)
    {
        RequirePerFaceColor(m);
        RequireFFAdjacency(m);
 
        std::vector< std::pair<int, typename MeshType::FacePointer> > CCV;
        int ScatterSize= std::min (100,tri::Clean<MeshType>::ConnectedComponents(m, CCV)); // number of random color to be used. Never use too many.
 
        ConnectedComponentIterator<MeshType> ci;
        for(unsigned int i=0;i<CCV.size();++i)
        {
            Color4b BaseColor = Color4b::Scatter(ScatterSize, i%ScatterSize,.4f,.7f);
            std::vector<typename MeshType::FacePointer> FPV;
            for(ci.start(m,CCV[i].second);!ci.completed();++ci)
                (*ci)->C()=BaseColor;
        }
    }
 
    static void PerFaceRandom(MeshType &m)
    {
        RequirePerFaceColor(m);
        FaceIterator fi;
        Color4b BaseColor = Color4b::Black;
        PerFaceConstant(m,BaseColor);
        int id_num=0;
        for(fi=m.face.begin();fi!=m.face.end();++fi)
            if(!(*fi).IsD())
            {
                id_num++;
                if((*fi).C() == BaseColor) (*fi).C() = Color4b::Scatter(50, id_num%50,.4f,.7f);
                for(int j=0;j<3;++j)
                    if((*fi).IsF(j))
                    {
                        assert(!IsBorder((*fi),j));
                        (*fi).FFp(j)->C()= (*fi).C();
                    }
            }
    }
 
    static void PerVertexPerlinNoise(MeshType& m, CoordType period, CoordType offset = CoordType(0, 0, 0), bool onSelected = false)
    {
        RequirePerVertexColor(m);
 
        CoordType p[3];
 
        for(VertexIterator vi = m.vert.begin(); vi!=m.vert.end(); ++vi)
            if(!(*vi).IsD())
                if ((!onSelected) || ((*vi).IsS()))
                {
                    // perlin noise is defined in 022
                    p[0] = (vi->P()/period[0])+offset;
                    p[1] = (vi->P()/period[1])+offset;
                    p[2] = (vi->P()/period[2])+offset;
                    (*vi).C() = Color4b(    int(127+128.0*math::Perlin::Noise(p[0][0],p[0][1],p[0][2])),
                            int(127+128.0*math::Perlin::Noise(p[1][0],p[1][1],p[1][2])),
                            int(127+128.0*math::Perlin::Noise(p[2][0],p[2][1],p[2][2])),
                            255 );
                }
 
    }
 
 
    static void PerVertexPerlinColoring(MeshType& m, ScalarType period, CoordType offset = CoordType(0, 0, 0), Color4b color1 = Color4b::Black, Color4b color2 = Color4b::White, bool onSelected = false)
    {
        RequirePerVertexColor(m);
 
        CoordType p;
 
        for (VertexIterator vi = m.vert.begin(); vi != m.vert.end(); ++vi)
            if (!(*vi).IsD())
                if ((!onSelected) || ((*vi).IsS()))
                {
                    // perlin noise is defined in 022
                    p = (vi->P() / period) + offset;
                    double factor = (math::Perlin::Noise(p[0], p[1], p[2]) + 1.0) / 2.0;
 
                    int rr = (color1[0] * factor) + (color2[0] * (1.0 - factor));
                    int gg = (color1[1] * factor) + (color2[1] * (1.0 - factor));
                    int bb = (color1[2] * factor) + (color2[2] * (1.0 - factor));
                    int aa = (color1[3] * factor) + (color2[3] * (1.0 - factor));
 
                    (*vi).C() = Color4b(rr, gg, bb, aa);
                }
    }
 
    static void PerVertexAddNoise(MeshType& m, int noiseBits, bool onSelected=false, int randSeed=0)
    {
        RequirePerVertexColor(m);
 
        if(noiseBits>8) noiseBits = 8;
        if(noiseBits<1) return;
 
        // randSeed==0 keeps the historical behaviour (a different result on every
        // call); pass a non-zero seed to make the noise exactly reproducible.
        math::SubtractiveRingRNG randomGen = math::SubtractiveRingRNG(randSeed ? randSeed : int(time(NULL)));
        for(VertexIterator vi = m.vert.begin(); vi!=m.vert.end(); ++vi)
            if(!(*vi).IsD())
                if ((!onSelected) || ((*vi).IsS()))
                {
                    (*vi).C()[0] = math::Clamp<int>((*vi).C()[0] + randomGen.generate(int(2*pow(2.0f,noiseBits))) - int(pow(2.0f,noiseBits)),0,255);
                    (*vi).C()[1] = math::Clamp<int>((*vi).C()[1] + randomGen.generate(int(2*pow(2.0f,noiseBits))) - int(pow(2.0f,noiseBits)),0,255);
                    (*vi).C()[2] = math::Clamp<int>((*vi).C()[2] + randomGen.generate(int(2*pow(2.0f,noiseBits))) - int(pow(2.0f,noiseBits)),0,255);
                }
 
    }
 
 
    static int PerVertexThresholding(MeshType &m, float threshold, const Color4b c1 = Color4<unsigned char>::Black, const Color4b c2 = Color4<unsigned char>::White, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    float value = ComputeLightness((*vi).C());
 
                    if(value<=threshold) (*vi).C() = c1;
                    else (*vi).C() = c2;
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    // Computes the lightness value for a specified color. lightness = 0.5*(Max(R,G,B)+Min(R,G,B))
    static float ComputeLightness(Color4b c)
    {
        float min_rgb = (float)math::Min(c[0],c[1],c[2]);
        float max_rgb = (float)math::Max(c[0],c[1],c[2]);
        return (max_rgb + min_rgb)/2;
    }
 
    static int PerVertexBrightness(MeshType &m, float amount, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = Color4b(
                                    math::Clamp(int((*vi).C()[0]+amount),0,255),
                            math::Clamp(int((*vi).C()[1]+amount),0,255),
                            math::Clamp(int((*vi).C()[2]+amount),0,255),
                            255);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    static int PerVertexContrast(MeshType &m, float factor, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorMul((*vi).C(),factor);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //Performs contrast operations on color, i.e expands or compress the histogram around
    //the midpoint value.  NewValue = (OldValue - 128) ◊ factor + 128
    static Color4b ColorMul(Color4b c, float factor)
    {
        return Color4b( ValueMul(c[0], factor), ValueMul(c[1], factor), ValueMul(c[2], factor), 1);
    }
 
    static int ValueMul(int value, float factor)
    {
        return math::Clamp<int>((int)((value - 128)*factor + 128), 0, 255);
    }
 
    static int PerVertexBrightnessContrast(MeshType &m, float brightness, float contrast, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorBrightnessContrast((*vi).C(),brightness,contrast);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    static Color4b ColorBrightnessContrast(Color4b c, float brightness, float contrast)
    {
        return Color4b( ValueBrightnessContrast(c[0], brightness, contrast),
                ValueBrightnessContrast(c[1], brightness, contrast),
                ValueBrightnessContrast(c[2], brightness, contrast), 1 );
    }
 
    static int ValueBrightnessContrast(unsigned char ivalue, float brightness, float contrast)
    {
        float value = float(ivalue)/255.0f;
        if (brightness < 0.0)  value = value * ( 1.0 + brightness);
        else value = value + ((1.0 - value) * brightness);
        value = (value - 0.5) * (tan ((contrast + 1) * M_PI/4) ) + 0.5;
        return math::Clamp<int>(255.0*value, 0, 255);
    }
 
    static int PerVertexInvert(MeshType &m, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        for(VertexIterator vi=m.vert.begin(); vi!=m.vert.end(); ++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    Color4b &c=(*vi).C();
                    c=Color4b( 255-c[0],255-c[1],255-c[2], 1);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    static int PerVertexGamma(MeshType &m, float gamma, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
 
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorPow((*vi).C(), 1/gamma);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //computes the standard gamma transformation on a given color, according to NewVal = OldVal^(1/gamma)
    static Color4b ColorPow(Color4b c, float exponent)
    {
        return vcg::Color4b(
                    math::Clamp((int)( ValuePow(float(c[0])/255, exponent)*255), 0, 255),
                math::Clamp((int)( ValuePow(float(c[1])/255, exponent)*255), 0, 255),
                math::Clamp((int)( ValuePow(float(c[2])/255, exponent)*255), 0, 255),
                255);
    }
 
    static float ValuePow(float value, float exponent)
    {
        return powf(value, exponent);
    }
 
    //useful bit masks for RGB channels, used for Levels filter.
    enum rgbChMask {ALL_CHANNELS = 7, RED_CHANNEL = 4, GREEN_CHANNEL = 2, BLUE_CHANNEL = 1, NO_CHANNELS = 0 };
 
    static int PerVertexLevels(MeshType &m, float gamma, float in_min, float in_max, float out_min, float out_max, unsigned char rgbMask, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorLevels((*vi).C(), gamma, in_min, in_max, out_min, out_max, rgbMask);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //Performs levels transformation on each channel set to 1 in the rgbMask.
    static Color4b ColorLevels(Color4b c, float gamma, float in_min, float in_max, float out_min, float out_max, unsigned char rgbMask)
    {
        unsigned char r = c[0], g = c[1], b = c[2];
        if(rgbMask & RED_CHANNEL) r = ValueLevels(c[0], gamma, in_min, in_max, out_min, out_max);
        if(rgbMask & GREEN_CHANNEL) g = ValueLevels(c[1], gamma, in_min, in_max, out_min, out_max);
        if(rgbMask & BLUE_CHANNEL) b = ValueLevels(c[2], gamma, in_min, in_max, out_min, out_max);
        return Color4b(r, g, b, 255);
    }
 
    //Transform on levels
    static int ValueLevels(int value, float gamma, float in_min, float in_max, float out_min, float out_max)
    {
        float fvalue = value/255.0f;
        // normalize
        fvalue = math::Clamp<float>(fvalue - in_min, 0.0f, 1.0f) / math::Clamp<float>(in_max - in_min, 1.0f/255.0f, 1.0f);
        // transform gamma
        fvalue = powf(fvalue,1/gamma);
        // rescale range
        fvalue = fvalue * (out_max - out_min) + out_min;
        //back in interval [0,255] and clamp
        return math::Clamp<int>((int)(fvalue * 255), 0, 255);
    }
 
    static int PerVertexColourisation(MeshType &m, Color4b c, float intensity, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi)
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorApplyDiff((*vi).C(), c, intensity);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    // Perform colourisation operation.
    // For each channel C:
    // newC = origC + intensity * (newC - origC)
    static Color4b ColorApplyDiff(Color4b old_color, Color4b new_color, float intensity)
    {
        return Color4b( ValueApplyDiff(old_color[0], new_color[0], intensity),
                ValueApplyDiff(old_color[1], new_color[1], intensity),
                ValueApplyDiff(old_color[2], new_color[2], intensity), 255);
    }
 
    static int ValueApplyDiff(int old_value, int new_value, float intensity)
    {
        return  math::Clamp<int>((int)(old_value + intensity * (new_value - old_value)), 0, 255);
    }
 
    //An useful ENUM to hold all desaturation methods.
    enum DesaturationMethods {M_LIGHTNESS = 0, M_LUMINOSITY = 1, M_AVERAGE = 2};
 
    static int PerVertexDesaturation(MeshType &m, int method, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        int counter=0;
        VertexIterator vi;
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C() = ColorDesaturate((*vi).C(), method);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //Desature the color. Ausiliary functions to calculate lightness/luminosity/average.
    static Color4b ColorDesaturate(Color4b c, int method)
    {
        switch(method){
            case M_LIGHTNESS:{
                int val = (int)ComputeLightness(c);
                return Color4b( val, val, val, 255);
            }
            case M_AVERAGE:{
                int val = (int)ComputeAvgLightness(c);
                return Color4b( val, val, val, 255);
            }
            case M_LUMINOSITY:{
                int val = (int)ComputeLuminosity(c);
                return Color4b( val, val, val, 255);
            }
            default: assert(0);
        }
        return Color4b(255, 255, 255, 255);
    }
 
    //ausiliary function to compute average lightness. value = (R+G+B)/3
    static float ComputeAvgLightness(Color4b c)
    {
        return float(c[0]+c[1]+c[2])/3.0f;
    }
 
    //ausiliary function to compute luminosity. value = 0.21*R+0.71*G+0.7*B
    static float ComputeLuminosity(Color4b c)
    {
        return float(0.2126f*c[0]+0.7152f*c[1]+0.0722f*c[2]);
    }
 
    static int PerVertexEqualize(MeshType &m, unsigned int rgbMask, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        //declares , resets and set up 4 histograms, for Red, Green, Blue and Lightness
        Histogramf Hl, Hr, Hg, Hb;
        Hl.Clear(); Hr.Clear(); Hg.Clear(); Hb.Clear();
        Hl.SetRange(0, 255, 255); Hr.SetRange(0, 255, 255); Hg.SetRange(0, 255, 255); Hb.SetRange(0, 255, 255);
 
        int counter=0;
        VertexIterator vi;
 
        //Scan the mesh to build the histograms
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, put it in the histograms
                {
                    float v = ComputeLightness((*vi).C())+0.5; //compute and round lightness value
                    Hl.Add(v); Hr.Add((float)(*vi).C()[0]); Hg.Add((float)(*vi).C()[1]); Hb.Add((float)(*vi).C()[2]);
                }
            }
        }
 
        //for each histogram, compute the cumulative distribution function, and build a lookup table
        int cdf_l[256], cdf_r[256], cdf_g[256], cdf_b[256];
        cdf_l[0] = Hl.BinCount(0); cdf_r[0] = Hr.BinCount(0); cdf_g[0] = Hg.BinCount(0); cdf_b[0] = Hb.BinCount(0);
        for(int i=1; i<256; i++){
            cdf_l[i] = Hl.BinCount(float(i)) + cdf_l[i-1];
            cdf_r[i] = Hr.BinCount(float(i)) + cdf_r[i-1];
            cdf_g[i] = Hg.BinCount(float(i)) + cdf_g[i-1];
            cdf_b[i] = Hb.BinCount(float(i)) + cdf_b[i-1];
        }
 
        //this loop aaplies the transformation to colors
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C()=ColorEqualize((*vi).C(), cdf_l, cdf_r, cdf_g, cdf_b, rgbMask);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //Applies equalization to the components of the color according to rgbmask
    static Color4b ColorEqualize(Color4b c, int cdf_l[256], int cdf_r[256], int cdf_g[256], int cdf_b[256], unsigned int rgbMask)
    {
        unsigned char r = c[0], g = c[1], b = c[2];
        if(rgbMask == NO_CHANNELS) //in this case, equalization is done on lightness
        {
            int v = ValueEqualize(cdf_l[(int)(ComputeLightness(c)+0.5f)], cdf_l[0], cdf_l[255]);
            return Color4b(v, v, v, 255); //return the equalized gray color
        }
        if(rgbMask & RED_CHANNEL) r = ValueEqualize(cdf_r[c[0]], cdf_r[0], cdf_r[255]); //Equalizes red
        if(rgbMask & GREEN_CHANNEL) g = ValueEqualize(cdf_g[c[1]], cdf_g[0], cdf_g[255]); //Equalizes green
        if(rgbMask & BLUE_CHANNEL) b = ValueEqualize(cdf_b[c[2]], cdf_b[0], cdf_b[255]); //Equalizes blue
        return Color4b(r, g, b, 255); //return the equalized color
    }
 
    //Compute the equalized value
    static int ValueEqualize(int cdfValue, int cdfMin, int cdfMax)
    {
        return int(float((cdfValue - cdfMin)/float(cdfMax - cdfMin)) * 255.0f);
    }
 
    static int PerVertexWhiteBalance(MeshType &m, Color4b userColor, const bool ProcessSelected=false)
    {
        RequirePerVertexColor(m);
 
        Color4b unbalancedWhite= userColor;
        int counter=0;
        VertexIterator vi;
 
        //in this loop the transformation is applied to the mesh
        for(vi=m.vert.begin();vi!=m.vert.end();++vi) //scan all the vertex...
        {
            if(!(*vi).IsD()) //if it has not been deleted...
            {
                if(!ProcessSelected || (*vi).IsS()) //if this vertex has been selected, do transormation
                {
                    (*vi).C()=ColorWhiteBalance((*vi).C(),unbalancedWhite);
                    ++counter;
                }
            }
        }
        return counter;
    }
 
    //Balnce the white of the color, applying a correction factor based on the unbalancedWhite color.
    static Color4b ColorWhiteBalance(Color4b c, Color4b unbalancedWhite)
    {
        //sanity check to avoid division by zero...
        if(unbalancedWhite[0]==0) unbalancedWhite[0]=1;
        if(unbalancedWhite[1]==0) unbalancedWhite[1]=1;
        if(unbalancedWhite[2]==0) unbalancedWhite[2]=1;
 
        return Color4b(
                    math::Clamp<int>((int)(c[0]*(255.0f/unbalancedWhite[0])), 0, 255),
                math::Clamp<int>((int)(c[1]*(255.0f/unbalancedWhite[1])), 0, 255),
                math::Clamp<int>((int)(c[2]*(255.0f/unbalancedWhite[2])), 0, 255),
                255);
    }
 
};
 
}// end namespace
}// end namespace
#endif