color.h

Go to the documentation of this file.

/*
// Copyright 2007 Alexandros Panagopoulos
//
// This software is distributed under the terms of the GNU Lesser General Public Licence
//
// This file is part of Be3D library.
//
//    Be3D is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Lesser General Public License as published by
//    the Free Software Foundation, either version 3 of the License, or
//    (at your option) any later version.
//
//    Be3D 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 Lesser General Public License for more details.
//
//    You should have received a copy of the GNU Lesser General Public License
//    along with Be3D.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef _COLOR_H2397_INCLUDED_
#define _COLOR_H2397_INCLUDED_

#pragma once

#include <math.h>

class Color {
 public:
    float r,g,b;

 public:
    Color() : r(0), g(0), b(0) { };
    Color(float _x, float _y, float _z) : r(_x), g(_y), b(_z) { };
    Color(const Color& v) : r(v.r), g(v.g), b(v.b) { };
    Color(const unsigned char *c) : r((float)c[0]/255.0f), g((float)c[1]/255.0f), b((float)c[2]/255.0f) { }

    inline float    length() const        { return sqrtf(r*r + g*g + b*b); }
    //inline float    length2() const        { return r*r + g*g + b*b; }
    //inline void        normalize()            { *this /= length(); }
    inline float    avg() const            { return (r + g + b)/3.0f; }

    // products (not as operators, to avoid confusion)
    //inline float    dot(const Color& v)    { return r*v.r + g*v.g + b*v.b; }
    //inline Color    cross(const Color& v)    { return Color(g*v.b-v.g*b, b*v.r-v.b*r, r*v.g-v.r*g); }

    inline Color compProduct(const Color& cl) { return Color(r*cl.r, g*cl.g, b*cl.b); }
    inline void    clampTop() { if (r>1) r=1; if (g>1) g=1; if (b>1) b=1; }
    inline void    clampBottom() { if (r<0) r=0; if (g<0) g=0; if (b<0) b=0; }
    inline void clamp()        { clampTop(); clampBottom(); }

    // unary operators
    friend inline Color    operator - (const Color& v)    { return Color(-v.r, -v.g, -v.b); }

    // scalar operators
    friend    inline Color    operator * (const Color& v, float f)    { return Color(v.r*f, v.g*f, v.b*f); };
    friend    inline Color    operator * (float f, const Color& v)    { return Color(v.r*f, v.g*f, v.b*f); };
    friend    inline Color    operator / (const Color& v, float f)    { return Color(v.r/f, v.g/f, v.b/f); };
    friend    inline Color    operator / (float f, const Color& v)    { return Color(v.r/f, v.g/f, v.b/f); };
            inline Color&    operator *= (float f)                    { r*=f; g*=f; b*=f; return *this; };
            inline Color&    operator /= (float f)                    { r/=f; g/=f; b/=f; return *this; };

    // vector operators
            inline Color&    operator += (const Color& v)                        { r+=v.r; g+=v.g; b+=v.b; return *this; };
            inline Color&    operator -= (const Color& v)                        { r-=v.r; g-=v.g; b-=v.b; return *this; };
    friend    inline Color    operator + (const Color& v1, const Color& v2)    { return Color(v1.r+v2.r, v1.g+v2.g, v1.b+v2.b); };
    friend    inline Color    operator - (const Color& v1, const Color& v2)    { return Color(v1.r-v2.r, v1.g-v2.g, v1.b-v2.b); };

    // equality operators
    inline bool operator == (const Color& v)        { return (v.r == r && v.g == g && v.b == b); }
    inline bool operator != (const Color& v)        { return (v.r == r && v.g == g && v.b == b); }
    inline bool equalsTheta (const Color& v, float theta)        { return ((fabs(v.r-r)<theta) && (fabs(v.g-g)<theta) && (fabs(v.b-b)<theta)); }

    // r,g,b values are from 0 to 1
    // h = [0,360], s = [0,1], v = [0,1]
    //        if s == 0, then h = 0  //changed from -1 (undefined)
    inline void toHSV(float *h, float *s, float *v ) {
        float min, max, delta;
        min = (r<g)?r:g;
        min = (min<b)?min:b;//MIN( r, g, b );
        max = (r>g)?r:g;
        max = (max>b)?max:b;//MAX( r, g, b );
        *v = max;                // v
        delta = max - min;
        if ( max != 0 )
            *s = delta / max;        // s
        else {
            *s = 0;
            *h = 0;    //-1;
            return;
        }
        if ( r == max )
            *h = ( g - b ) / delta;        // between yellow & magenta
        else if ( g == max )
            *h = 2 + ( b - r ) / delta;    // between cyan & yellow
        else
            *h = 4 + ( r - g ) / delta;    // between magenta & cyan
        *h *= 60;                // degrees
        if ( *h < 0 )
            *h += 360;
    }

    static inline Color fromHSV(float h, float s, float v) {
        Color c;
        int i;
        float f, p, q, t;

        if ( s == 0 ) {
            // achromatic (grey)
            c.r = c.g = c.b = v;
            return c;
        }

        h /= 60;            // sector 0 to 5
        i = (int)floor(h);
        f = h - i;            // factorial part of h
        p = v * ( 1 - s );
        q = v * ( 1 - s * f );
        t = v * ( 1 - s * ( 1 - f ) );

        switch ( i ) {
            case 0:
                c.r = v;
                c.g = t;
                c.b = p;
                break;
            case 1:
                c.r = q;
                c.g = v;
                c.b = p;
                break;
            case 2:
                c.r = p;
                c.g = v;
                c.b = t;
                break;
            case 3:
                c.r = p;
                c.g = q;
                c.b = v;
                break;
            case 4:
                c.r = t;
                c.g = p;
                c.b = v;
                break;
            case 5:        // case 5:
            default:
                c.r = v;
                c.g = p;
                c.b = q;
                break;
        //    default:
        //        ASSERT(0);
        }
        return c;
    }
};

#endif