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Colour.h

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/*
    File:           Colour.h
    
    Function:       Definitions and classes for handling Colour

    Author(s):      Andrew Willmott

    Copyright:      (c) 1995-2000, Andrew Willmott
 */
 
#ifndef __Colour__
#define __Colour__

#include "gcl/GCLConfig.h"

#ifndef GCL_CLR_DOUBLE
#include "vl/VLf.h"
typedef Vec3f Colour;
typedef Vec4f Colour4;
typedef Mat3f ClrMat;
typedef Mat4f ClrTrans;
typedef Float ClrReal;
#else
#include "vl/VLd.h"
typedef Vec3d Colour;
typedef Vec4d Colour4;
typedef Mat3d ClrMat;
typedef Mat4d ClrTrans;
typedef Double ClrReal;
#endif

#include "cl/Array.h"
#include "cl/NArray.h"

inline Colour   RGBCol(ClrReal r, ClrReal g, ClrReal b)
                { return(Colour(r, g, b)); }
Colour          HSVCol(ClrReal hue, ClrReal saturation, ClrReal value);

typedef Colour Reflectance;
typedef NArray<Colour> ColourList;
typedef NArray<Colour4> Colour4List;
typedef ColourList ReflList;

Colour &ClipColour(Colour &c);
Colour &ClipColourZero(Colour &c);
inline Colour ClrMix(const Colour &c1, const Colour &c2, ClrReal mix)
{
    return(c1 * (1.0 - mix) + c2 * mix);
}


// --- Useful conversion factors/functions ------------------------------------

const Reflectance cRGBToNTSCLum(0.299, 0.587, 0.114);   
const Reflectance cRGBToLum(0.3086, 0.6094, 0.0820);    

const ClrMat cNTSCToCIE(
                0.67, 0.21, 0.14,           // From Sillion & Puesch
                0.33, 0.71, 0.08,           // "Radiosity", pp 211.
                0.00, 0.08, 0.78); 

const ClrMat cCIEToNTSC(
                1.730, -0.482, -0.261,
               -0.814,  1.652, -0.023,
                0.083, -0.169,  1.284); 

const ClrMat cRGBToYIQ(
                0.299,  0.587,  0.114,
                0.596, -0.275, -0.321,
                0.212, -0.523,  0.311);

const ClrMat cYIQToRGB(
                1.0,   0.956,   0.621,
                1.0,  -0.272,  -0.647,
                1.0,  -1.105,   1.702);

Colour YUVToRGB(const Colour &yuv);
Colour RGBToYUV(const Colour &rgb);


// --- Useful colour constants ------------------------------------------------

// RGB Constants

const Colour cBlack(0, 0, 0);
const Colour cWhite(1, 1, 1);

const Colour cGrey(cWhite * 0.5);
const Colour cGrey05(cWhite * 0.05);
const Colour cGrey10(cWhite * 0.1);
const Colour cGrey25(cWhite * 0.25);
const Colour cGrey50(cWhite * 0.5);
const Colour cGrey75(cWhite * 0.75);
const Colour cGrey90(cWhite * 0.90);
const Colour cGrey95(cWhite * 0.95);

const Colour cRed(1, 0, 0);
const Colour cOrange(1, 0.5, 0);
const Colour cYellow(1, 1, 0);
const Colour cGreen(0, 1, 0);
const Colour cCyan(0, 1, 1);
const Colour cBlue(0, 0, 1);
const Colour cPurple(1, 0, 1);

// HSV constants

const Int hsvRed    =    0;
const Int hsvOrange =   30;
const Int hsvYellow =   60;
const Int hsvGreen  =  120;
const Int hsvCyan   =  180;
const Int hsvBlue   =  240;
const Int hsvPurple =  300;


// --- Colour transformations -------------------------------------------------


ClrTrans    RGBScale(ClrReal rscale, ClrReal gscale, ClrReal bscale);
ClrTrans    RGBOffset(const Colour &c);
ClrTrans    RGBReplace(const Colour &c);
ClrTrans    RGBToLum();

ClrTrans    RGBSaturate(ClrReal sat);
ClrTrans    RGBPixelMix(ClrReal mix, const Colour &c);
ClrTrans    RGBHueRotate(ClrReal degrees);
#endif

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