// Persistence of Vision Ray Tracer Scene Description File
// Vers: 3.5
// File: $Id: Gamma.inc,v 1.3 2006/06/24 12:25:38 billh Exp $
// Desc: $Log: Gamma.inc,v $
// Desc: Revision 1.3  2006/06/24 12:25:38  billh
// Desc: added filter and transmit variants
// Desc:
// Desc: Revision 1.2  2006/06/24 11:51:39  billh
// Desc: added brief documentation
// Desc:
// Desc: Revision 1.1  2006/06/02 21:11:57  billh
// Desc: Gamma macro for individual colours
// Desc:
// Date: $Date: 2006/06/24 12:25:38 $
// Auth: $Author: billh $
//

// use Gamma(Colour, GammaCorrection)
//
// GammaCorrection
//     0  - black
//     <1 - darker
//     1  - the original colour
//     >1 - brighter

#ifndef (GAMMA_INCLUDED)
#declare GAMMA_INCLUDED = version;

#macro Gamma(C, G)
    rgb<
        pow(C.red, 1/G),
        pow(C.green, 1/G),
        pow(C.blue, 1/G)
    >
#end

#macro GammaF(C, G)
    rgbf<
        pow(C.red, 1/G),
        pow(C.green, 1/G),
        pow(C.blue, 1/G),
        pow(C.filter, 1/G)
    >
#end

#macro GammaT(C, G)
    rgbt<
        pow(C.red, 1/G),
        pow(C.green, 1/G),
        pow(C.blue, 1/G),
        pow(C.transmit, 1/G)
    >
#end

#macro GammaFT(C, G)
    rgbft<
        pow(C.red, 1/G),
        pow(C.green, 1/G),
        pow(C.blue, 1/G),
        pow(C.filter, 1/G),
        pow(C.transmit, 1/G)
    >
#end

#version GAMMA_INCLUDED;
#end