💿🐜 Antkeeper source code
https://antkeeper.com
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164 lines
4.1 KiB
164 lines
4.1 KiB
/*
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* Copyright (C) 2021 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_SRGB_HPP
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#define ANTKEEPER_COLOR_SRGB_HPP
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#include "math/math.hpp"
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#include <cmath>
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namespace color {
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/// Functions which operate in the sRGB colorspace.
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namespace srgb {
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/**
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* Performs the sRGB Electro-Optical Transfer Function (EOTF), also known as the sRGB decoding function.
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*
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* @param v sRGB electrical signal (gamma-encoded sRGB).
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* @return Corresponding luminance of the signal (linear sRGB).
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*/
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/// @{
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float eotf(float v);
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double eotf(double v);
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template <class T>
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math::vector3<T> eotf(const math::vector3<T>& v);
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/// @}
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/**
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* Performs the sRGB inverse Electro-Optical Transfer Function (EOTF), also known as the sRGB encoding function.
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*
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* @param l sRGB luminance (linear sRGB).
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* @return Corresponding electrical signal (gamma-encoded sRGB).
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*/
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/// @{
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float eotf_inverse(float v);
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double eotf_inverse(double v);
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template <class T>
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math::vector3<T> eotf_inverse(const math::vector3<T>& l);
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/// @}
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/**
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* Calculates the luminance of a linear sRGB color.
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*
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* @param x Linear sRGB color.
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* @return return Luminance of @p x.
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*/
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template <class T>
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T luminance(const math::vector3<T>& x);
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/**
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* Transforms a linear sRGB color into the ACEScg colorspace using the Bradford chromatic adaption transform.
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*
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* @param x Linear sRGB color.
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* @return ACEScg color.
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*
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* @see https://www.colour-science.org/apps/
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*/
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template <class T>
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math::vector3<T> to_acescg(const math::vector3<T>& x);
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/**
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* Transforms a linear sRGB color into the CIE XYZ colorspace.
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*
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* @param x Linear sRGB color.
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* @return CIE XYZ color.
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*/
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template <class T>
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math::vector3<T> to_xyz(const math::vector3<T>& x);
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inline float eotf(float v)
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{
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return (v < 0.04045f) ? (v / 12.92f) : std::pow((v + 0.055f) / 1.055f, 2.4f);
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}
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inline double eotf(double v)
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{
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return (v < 0.04045) ? (v / 12.92) : std::pow((v + 0.055) / 1.055, 2.4);
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}
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template <class T>
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math::vector3<T> eotf(const math::vector3<T>& v)
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{
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return math::vector3<T>
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{
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eotf(v[0]),
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eotf(v[1]),
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eotf(v[2])
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};
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}
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inline float eotf_inverse(float l)
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{
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return (l <= 0.0031308f) ? (l * 12.92f) : (std::pow(l, 1.0f / 2.4f) * 1.055f - 0.055f);
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}
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inline double eotf_inverse(double l)
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{
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return (l <= 0.0031308) ? (l * 12.92) : (std::pow(l, 1.0 / 2.4) * 1.055 - 0.055);
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}
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template <class T>
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math::vector3<T> eotf_inverse(const math::vector3<T>& l)
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{
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return math::vector3<T>
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{
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eotf_inverse(l[0]),
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eotf_inverse(l[1]),
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eotf_inverse(l[2])
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};
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}
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template <class T>
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T luminance(const math::vector3<T>& x)
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{
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static const math::vector3<T> luma = {0.212639005871510, 0.715168678767756, 0.072192315360734};
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return math::dot(x, luma);
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}
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template <class T>
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math::vector3<T> to_acescg(const math::vector3<T>& x)
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{
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static const math::matrix3<T> srgb_to_acescg
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{{
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{0.613132422390542, 0.070124380833917, 0.020587657528185},
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{0.339538015799666, 0.916394011313573, 0.109574571610682},
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{0.047416696048269, 0.013451523958235, 0.869785404035327}
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}};
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return srgb_to_acescg * x;
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}
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template <class T>
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math::vector3<T> to_xyz(const math::vector3<T>& x)
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{
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static const math::matrix3<T> srgb_to_xyz
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{{
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{0.412390799265959, 0.212639005871510, 0.019330818715592},
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{0.357584339383878, 0.715168678767756, 0.119194779794626},
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{0.180480788401834, 0.072192315360734, 0.950532152249661}
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}};
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return srgb_to_xyz * x;
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}
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} // namespace srgb
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} // namespace color
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#endif // ANTKEEPER_COLOR_SRGB_HPP
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