💿🐜 Antkeeper source code
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103 lines
3.4 KiB
103 lines
3.4 KiB
/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_COLOR_CAT_HPP
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#define ANTKEEPER_COLOR_CAT_HPP
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#include <engine/math/matrix.hpp>
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#include <engine/math/vector.hpp>
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namespace color {
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/// @name Chromatic adaption transforms (CAT)
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/// @{
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/**
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* Bradford cone response matrix.
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*
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* @see Specification ICC.1:2010 (Profile version 4.3.0.0). Image technology colour management — Architecture, profile format, and data structure, Annex E.3, pp. 102.
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* @see http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
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*/
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template <class T>
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constexpr math::mat3<T> bradford_cone_response =
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{
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T{ 0.8951}, T{-0.7502}, T{ 0.0389},
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T{ 0.2664}, T{ 1.7135}, T{-0.0685},
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T{-0.1614}, T{ 0.0367}, T{ 1.0296}
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};
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/**
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* von Kries cone response matrix.
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*
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* @see http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
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*/
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template <class T>
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constexpr math::mat3<T> von_kries_cone_response =
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{
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T{ 0.40024}, T{-0.22630}, T{0.00000},
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T{ 0.70760}, T{ 1.16532}, T{0.00000},
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T{-0.08081}, T{ 0.04570}, T{0.91822}
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};
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/**
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* XYZ scaling cone response matrix.
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*
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* @see http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
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*/
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template <class T>
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constexpr math::mat3<T> xyz_scaling_cone_response = math::mat3<T>::identity();
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/**
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* Constructs a chromatic adaptation transform (CAT) matrix.
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*
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* @param w0 CIE xy chromaticity coordinates of the source illuminant.
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* @param w1 CIE xy chromaticity coordinates of the destination illuminant.
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* @param cone_response Cone response matrix.
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*
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* @return CAT matrix.
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*
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* @see Specification ICC.1:2010 (Profile version 4.3.0.0). Image technology colour management — Architecture, profile format, and data structure, Annex E.3, pp. 102.
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* @see http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
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*/
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template <class T>
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[[nodiscard]] constexpr math::mat3<T> cat_matrix(const math::vec2<T>& w0, const math::vec2<T>& w1, const math::mat3<T>& cone_response = bradford_cone_response<T>) noexcept
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{
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// Convert CIE xy chromaticity coordinates to CIE XYZ colors
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const math::vec3<T> w0_xyz = {w0[0] / w0[1], T{1}, (T{1} - w0[0] - w0[1]) / w0[1]};
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const math::vec3<T> w1_xyz = {w1[0] / w1[1], T{1}, (T{1} - w1[0] - w1[1]) / w1[1]};
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// Calculate cone response of CIE XYZ colors
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const math::vec3<T> w0_cone_response = cone_response * w0_xyz;
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const math::vec3<T> w1_cone_response = cone_response * w1_xyz;
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const math::mat3<T> scale =
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{
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w1_cone_response[0] / w0_cone_response[0], T{0}, T{0},
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T{0}, w1_cone_response[1] / w0_cone_response[1], T{0},
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T{0}, T{0}, w1_cone_response[2] / w0_cone_response[2],
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};
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return math::inverse(cone_response) * scale * cone_response;
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}
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/// @}
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} // namespace color
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#endif // ANTKEEPER_COLOR_CAT_HPP
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