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/*
* MIT License
*
* Copyright (c) 2023-2024 yum_food
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE
* SOFTWARE.
*/
#ifndef __OKLAB_INC
#define __OKLAB_INC
// Utilities relating to the OKLAB color space, as defined here:
// https://bottosson.github.io/posts/oklab/
// Code is derived from the samples there, which are in the public domain.
// Weights: https://en.wikipedia.org/wiki/SRGB
float3 LRGBtoXYZ(float3 c) {
float3x3 rgb_to_xyz = float3x3(
0.4124, 0.3576, 0.1805,
0.2126, 0.7152, 0.0722,
0.0193, 0.1192, 0.9505);
return saturate(mul(rgb_to_xyz, c));
}
// Weights: https://en.wikipedia.org/wiki/SRGB
float3 XYZtoLRGB(float3 c) {
float3x3 xyz_to_rgb = float3x3(
3.24062548, -1.53720797, -0.4986286,
-0.96893071, 1.87575606, 0.04151752,
0.05571012, -0.20402105, 1.05699594);
return saturate(mul(xyz_to_rgb, c));
}
// Source: https://bottosson.github.io/posts/oklab/
float3 XYZtoOKLAB(float3 c) {
float3x3 m1 = float3x3(
0.8189330101, 0.3618667424, -0.1288597137,
0.0329845436, 0.9293118715, 0.0361456387,
0.0482003018, 0.2643662691, 0.6338517070);
float3x3 m2 = float3x3(
0.2104542553, 0.7936177850, -0.0040720468,
1.9779984951, -2.4285922050, 0.4505937099,
0.0259040371, 0.7827717662, -0.8086757660);
c = mul(m1, c);
c = pow(c, 0.33333333333);
return mul(m2, c);
}
// Source: https://bottosson.github.io/posts/oklab/
float3 OKLABtoXYZ(float3 c) {
float3x3 m1i = float3x3(
1.22701385, -0.55779998, 0.28125615,
-0.04058018, 1.11225687, -0.07167668,
-0.07638128, -0.42148198, 1.58616322);
float3x3 m2i = float3x3(
1.00000000, 0.39633779, 0.21580376,
1.00000001, -0.10556134, -0.06385417,
1.00000005, -0.08948418, -1.29148554);
c = mul(m2i, c);
c = pow(c, 3);
return mul(m1i, c);
}
// Source: https://bottosson.github.io/posts/oklab/
float3 OKLABtoOKLCH(float3 c) {
float c_ = length(c.yz);
float h_ = atan2(c.z, c.y);
return float3(c.x, c_, h_);
}
// Source: https://bottosson.github.io/posts/oklab/
// Note: hue must be in units of radians.
float3 OKLCHtoOKLAB(float3 c) {
float a = c.y * cos(c.z);
float b = c.y * sin(c.z);
return float3(c.x, a, b);
}
float3 LRGBtoOKLAB(float3 c) {
return XYZtoOKLAB(LRGBtoXYZ(c));
}
float3 OKLABtoLRGB(float3 c) {
return XYZtoLRGB(OKLABtoXYZ(c));
}
float3 LRGBtoOKLCH(float3 c) {
return OKLABtoOKLCH(XYZtoOKLAB(LRGBtoXYZ(c)));
}
float3 OKLCHtoLRGB(float3 c) {
return XYZtoLRGB(OKLABtoXYZ(OKLCHtoOKLAB(c)));
}
#endif // __OKLAB_INC
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