slang-shaders/misc/white_point.slang
2020-03-31 18:55:49 +01:00

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#version 450
// White Point Mapping
// ported by Dogway
//
// From the first comment post (sRGB primaries and linear light compensated)
// http://www.zombieprototypes.com/?p=210#comment-4695029660
// Based on the Neil Bartlett's blog update
// http://www.zombieprototypes.com/?p=210
// Inspired itself by Tanner Helland's work
// http://www.tannerhelland.com/4435/convert-temperature-rgb-algorithm-code/
layout(push_constant) uniform Push
{
vec4 SourceSize;
vec4 OriginalSize;
vec4 OutputSize;
uint FrameCount;
float temperature;
float luma_preserve;
float wp_red;
float wp_green;
float wp_blue;
} params;
#pragma parameter temperature "White Point" 9311.0 1031.0 12047.0 72.0
#pragma parameter luma_preserve "Preserve Luminance" 1.0 0.0 1.0 1.0
#pragma parameter wp_red "Red Shift" 0.0 -1.0 1.0 0.01
#pragma parameter wp_green "Green Shift" 0.0 -1.0 1.0 0.01
#pragma parameter wp_blue "Blue Shift" 0.0 -1.0 1.0 0.01
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
} global;
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
void main()
{
gl_Position = global.MVP * Position;
vTexCoord = TexCoord;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
vec3 wp_adjust(vec3 color){
float temp = params.temperature / 100.;
float k = params.temperature / 10000.;
float lk = log(k);
vec3 wp = vec3(1.);
// calculate RED
wp.r = (temp <= 65.) ? 1. : 0.32068362618584273 + (0.19668730877673762 * pow(k - 0.21298613432655075, - 1.5139012907556737)) + (- 0.013883432789258415 * lk);
// calculate GREEN
float mg = 1.226916242502167 + (- 1.3109482654223614 * pow(k - 0.44267061967913873, 3.) * exp(- 5.089297600846147 * (k - 0.44267061967913873))) + (0.6453936305542096 * lk);
float pg = 0.4860175851734596 + (0.1802139719519286 * pow(k - 0.14573069517701578, - 1.397716496795082)) + (- 0.00803698899233844 * lk);
wp.g = (temp <= 65.5) ? ((temp <= 8.) ? 0. : mg) : pg;
// calculate BLUE
wp.b = (temp <= 19.) ? 0. : (temp >= 66.) ? 1. : 1.677499032830161 + (- 0.02313594016938082 * pow(k - 1.1367244820333684, 3.) * exp(- 4.221279555918655 * (k - 1.1367244820333684))) + (1.6550275798913296 * lk);
// clamp
wp.rgb = clamp(wp.rgb, vec3(0.), vec3(1.));
// R/G/B independent manual White Point adjustment
wp.rgb += vec3(params.wp_red, params.wp_green, params.wp_blue);
// Linear color input
return color * wp;
}
vec3 sRGB_to_XYZ(vec3 RGB){
const mat3x3 m = mat3x3(
0.4124564, 0.3575761, 0.1804375,
0.2126729, 0.7151522, 0.0721750,
0.0193339, 0.1191920, 0.9503041);
return RGB * m;
}
vec3 XYZtoYxy(vec3 XYZ){
float XYZrgb = XYZ.r+XYZ.g+XYZ.b;
float Yxyr = XYZ.g;
float Yxyg = (XYZrgb <= 0.0) ? 0.3805 : XYZ.r / XYZrgb;
float Yxyb = (XYZrgb <= 0.0) ? 0.3769 : XYZ.g / XYZrgb;
return vec3(Yxyr,Yxyg,Yxyb);
}
vec3 XYZ_to_sRGB(vec3 XYZ){
const mat3x3 m = mat3x3(
3.2404542, -1.5371385, -0.4985314,
-0.9692660, 1.8760108, 0.0415560,
0.0556434, -0.2040259, 1.0572252);
return XYZ * m;
}
vec3 YxytoXYZ(vec3 Yxy){
float Xs = Yxy.r * (Yxy.g/Yxy.b);
float Xsz = (Yxy.r <= 0.0) ? 0 : 1;
vec3 XYZ = vec3(Xsz,Xsz,Xsz) * vec3(Xs, Yxy.r, (Xs/Yxy.g)-Xs-Yxy.r);
return XYZ;
}
vec3 linear_to_sRGB(vec3 color, float gamma){
color = clamp(color, 0.0, 1.0);
color.r = (color.r <= 0.00313066844250063) ?
color.r * 12.92 : 1.055 * pow(color.r, 1.0 / gamma) - 0.055;
color.g = (color.g <= 0.00313066844250063) ?
color.g * 12.92 : 1.055 * pow(color.g, 1.0 / gamma) - 0.055;
color.b = (color.b <= 0.00313066844250063) ?
color.b * 12.92 : 1.055 * pow(color.b, 1.0 / gamma) - 0.055;
return color.rgb;
}
vec3 sRGB_to_linear(vec3 color, float gamma){
color = clamp(color, 0.0, 1.0);
color.r = (color.r <= 0.04045) ?
color.r / 12.92 : pow((color.r + 0.055) / (1.055), gamma);
color.g = (color.g <= 0.04045) ?
color.g / 12.92 : pow((color.g + 0.055) / (1.055), gamma);
color.b = (color.b <= 0.04045) ?
color.b / 12.92 : pow((color.b + 0.055) / (1.055), gamma);
return color.rgb;
}
void main()
{
vec3 original = sRGB_to_linear(texture(Source, vTexCoord).rgb, 2.40);
vec3 adjusted = wp_adjust(original);
vec3 base_luma = XYZtoYxy(sRGB_to_XYZ(original));
vec3 adjusted_luma = XYZtoYxy(sRGB_to_XYZ(adjusted));
adjusted = (params.luma_preserve == 1.0) ? adjusted_luma + (vec3(base_luma.r,0.,0.) - vec3(adjusted_luma.r,0.,0.)) : adjusted_luma;
FragColor = vec4(linear_to_sRGB(XYZ_to_sRGB(YxytoXYZ(adjusted)), 2.40), 1.0);
}