srgb.hpp

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/*
 * Copyright (C) 2023  Christopher J. Howard
 *
 * This file is part of Antkeeper source code.
 *
 * Antkeeper source code 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 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper source code 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef ANTKEEPER_COLOR_SRGB_HPP
#define ANTKEEPER_COLOR_SRGB_HPP
 
#include <engine/color/rgb.hpp>
#include <engine/color/illuminants.hpp>
#include <engine/math/vector.hpp>
#include <cmath>
 
namespace color {
 
 
template <class T>
[[nodiscard]] math::vec3<T> srgb_oetf(const math::vec3<T>& x)
{
    auto f = [](T x) -> T
    {
        return x > T{0.0031308} ? std::pow(x, T{1.0 / 2.4}) * T{1.055} - T{0.055} : x * T{12.92};
    };
    
    return {f(x[0]), f(x[1]), f(x[2])};
}
 
template <class T>
[[nodiscard]] math::vec3<T> srgb_eotf(const math::vec3<T>& x)
{
    auto f = [](T x) -> T
    {
        return x > T{0.0031308 * 12.92} ? std::pow((x + T{0.055}) / T{1.055}, T{2.4}) : x / T{12.92};
    };
    
    return {f(x[0]), f(x[1]), f(x[2])};
}
 
template <class T>
constexpr rgb_color_space<T> srgb
(
    {T{0.64}, T{0.33}},
    {T{0.30}, T{0.60}},
    {T{0.15}, T{0.06}},
    deg2_d65<T>,
    &srgb_eotf<T>,
    &srgb_oetf<T>
);
 
 
} // namespace color
 
#endif // ANTKEEPER_COLOR_SRGB_HPP