Sorry, I entertained myself debugging a possible chroma banding issue, anyways here it is:
grade_(noLUT).slang
#version 450
layout(push_constant) uniform Push
{
float gamma_out;
float gamma_in;
float gamma_type;
float vignette;
float str;
float power;
float temperature;
float luma_preserve;
float sat;
float dulvibr;
float lum;
float size;
float cntrst;
float mid;
float black_level;
float blr;
float blg;
float blb;
float r;
float g;
float b;
float rg;
float rb;
float gr;
float gb;
float br;
float bg;
} params;
/*
Grade
> Ubershader grouping some color related monolithic shaders like color-mangler, vignette, white_point,
> and the addition of vibrance, black level, sigmoidal contrast and proper gamma transforms.
Author: hunterk, Guest, Dr. Venom, Dogway
License: Public domain
*/
#pragma parameter gamma_out "Display Gamma" 2.20 0.0 3.0 0.05
#pragma parameter gamma_in "CRT Gamma" 2.40 0.0 3.0 0.05
#pragma parameter gamma_type "CRT Gamma (POW = 0, sRGB = 1)" 1.0 0.0 1.0 1.0
#pragma parameter vignette "Vignette Toggle" 1.0 0.0 1.0 1.0
#pragma parameter str "Vignette Strength" 40.0 10.0 40.0 1.0
#pragma parameter power "Vignette Power" 0.20 0.0 0.5 0.01
#pragma parameter temperature "White Point" 9311.0 1031.0 12047.0 72.0
#pragma parameter luma_preserve "WP Preserve Luminance" 1.0 0.0 1.0 1.0
#pragma parameter sat "Saturation" 0.0 -1.0 2.0 0.02
#pragma parameter dulvibr "Dullness/Vibrance" 0.0 -1.0 1.0 0.05
#pragma parameter lum "Brightness" 1.0 0.0 2.0 0.01
#pragma parameter cntrst "Contrast" 0.0 -1.0 1.0 0.05
#pragma parameter mid "Contrast Pivot" 0.5 0.0 1.0 0.01
#pragma parameter black_level "Black Level" 0.0 -0.5 0.5 0.01
#pragma parameter blr "Black-Red Tint" 0.0 0.0 1.0 0.005
#pragma parameter blg "Black-Green Tint" 0.0 0.0 1.0 0.005
#pragma parameter blb "Black-Blue Tint" 0.0 0.0 1.0 0.005
#pragma parameter r "White-Red Tint" 1.0 0.0 2.0 0.01
#pragma parameter g "White-Green Tint" 1.0 0.0 2.0 0.01
#pragma parameter b "White-Blue Tint" 1.0 0.0 2.0 0.01
#pragma parameter rg "Red-Green Tint" 0.0 -1.0 1.0 0.005
#pragma parameter rb "Red-Blue Tint" 0.0 -1.0 1.0 0.005
#pragma parameter gr "Green-Red Tint" 0.0 -1.0 1.0 0.005
#pragma parameter gb "Green-Blue Tint" 0.0 -1.0 1.0 0.005
#pragma parameter br "Blue-Red Tint" 0.0 -1.0 1.0 0.005
#pragma parameter bg "Blue-Green Tint" 0.0 -1.0 1.0 0.005
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
vec4 SourceSize;
vec4 OriginalSize;
vec4 OutputSize;
} 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;
// White Point Mapping function
//
// 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/
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.));
// 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 Yxyg = (XYZrgb <= 0.0) ? 0.3805 : XYZ.r / XYZrgb;
float Yxyb = (XYZrgb <= 0.0) ? 0.3769 : XYZ.g / XYZrgb;
return vec3(XYZ.g, 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) ? 0.0 : 1.0;
vec3 XYZ = vec3(Xsz,Xsz,Xsz) * vec3(Xs, Yxy.r, (Xs/Yxy.g)-Xs-Yxy.r);
return XYZ;
}
// This shouldn't be necessary but it seems some undefined values can
// creep in and each GPU vendor handles that differently. This keeps
// all values within a safe range
vec3 mixfix(vec3 a, vec3 b, float c)
{
return (a.z < 1.0) ? mix(a, b, c) : a;
}
vec4 mixfix_v4(vec4 a, vec4 b, float c)
{
return (a.z < 1.0) ? mix(a, b, c) : a;
}
float SatMask(float color_r, float color_g, float color_b)
{
float max_rgb = max(color_r, max(color_g, color_b));
float min_rgb = min(color_r, min(color_g, color_b));
float msk = clamp((max_rgb - min_rgb) / (max_rgb + min_rgb), 0.0, 1.0);
return msk;
}
float moncurve_r( float color, float gamma, float offs)
{
// Reverse monitor curve
color = clamp(color, 0.0, 1.0);
float yb = pow( offs * gamma / ( ( gamma - 1.0) * ( 1.0 + offs)), gamma);
float rs = pow( ( gamma - 1.0) / offs, gamma - 1.0) * pow( ( 1.0 + offs) / gamma, gamma);
color = ( color > yb) ? ( 1.0 + offs) * pow( color, 1.0 / gamma) - offs : color * rs;
return color;
}
vec3 moncurve_r_f3( vec3 color, float gamma, float offs)
{
color.r = moncurve_r( color.r, gamma, offs);
color.g = moncurve_r( color.g, gamma, offs);
color.b = moncurve_r( color.b, gamma, offs);
return color.rgb;
}
float moncurve_f( float color, float gamma, float offs)
{
// Forward monitor curve
color = clamp(color, 0.0, 1.0);
float fs = (( gamma - 1.0) / offs) * pow( offs * gamma / ( ( gamma - 1.0) * ( 1.0 + offs)), gamma);
float xb = offs / ( gamma - 1.0);
color = ( color > xb) ? pow( ( color + offs) / ( 1.0 + offs), gamma) : color * fs;
return color;
}
vec3 moncurve_f_f3( vec3 color, float gamma, float offs)
{
color.r = moncurve_f( color.r, gamma, offs);
color.g = moncurve_f( color.g, gamma, offs);
color.b = moncurve_f( color.b, gamma, offs);
return color.rgb;
}
// Performs better in gamma encoded space
float contrast_sigmoid(float color, float cont, float pivot){
cont = pow(cont + 1., 3.);
float knee = 1. / (1. + exp(cont * pivot));
float shldr = 1. / (1. + exp(cont * (pivot - 1.)));
color = (1. / (1. + exp(cont * (pivot - color))) - knee) / (shldr - knee);
return color;
}
// Performs better in gamma encoded space
float contrast_sigmoid_inv(float color, float cont, float pivot){
cont = pow(cont - 1., 3.);
float knee = 1. / (1. + exp (cont * pivot));
float shldr = 1. / (1. + exp (cont * (pivot - 1.)));
color = pivot - log(1. / (color * (shldr - knee) + knee) - 1.) / cont;
return color;
}
void main()
{
// Pure power was crushing blacks (eg. DKC2). You can mimic pow(c, 2.4) by raising the gamma_in value to 2.55
vec3 imgColor = texture(Source, vTexCoord.xy).rgb;
imgColor = (params.gamma_type == 1.0) ? moncurve_f_f3(imgColor, params.gamma_in + 0.15, 0.055) : pow(imgColor, vec3(params.gamma_in));
// Saturation agnostic sigmoidal contrast
vec3 Yxy = XYZtoYxy(sRGB_to_XYZ(imgColor));
float toLinear = moncurve_r(Yxy.r, 2.40, 0.055);
float sigmoid = (params.cntrst > 0.0) ? contrast_sigmoid(toLinear, params.cntrst, params.mid) : contrast_sigmoid_inv(toLinear, params.cntrst, params.mid);
vec3 contrast = vec3(moncurve_f(sigmoid, 2.40, 0.055), Yxy.g, Yxy.b);
vec3 XYZsrgb = clamp(XYZ_to_sRGB(YxytoXYZ(contrast)), 0.0, 1.0);
contrast = (params.cntrst == 0.0) ? imgColor : XYZsrgb;
// Vignetting & Black Level
vec2 vpos = vTexCoord*(global.OriginalSize.xy/global.SourceSize.xy);
vpos *= 1.0 - vpos.xy;
float vig = vpos.x*vpos.y * params.str;
vig = min(pow(vig, params.power), 1.0);
contrast *= (params.vignette == 1.0) ? vig : 1.0;
contrast += (params.black_level / 20.0) * (1.0 - contrast);
// RGB related transforms
vec4 screen = vec4(max(contrast, 0.0), 1.0);
float sat = params.sat + 1.0;
// r g b alpha ; alpha does nothing for our purposes
mat4 color = mat4(params.r, params.rg, params.rb, 0.0, //red tint
params.gr, params.g, params.gb, 0.0, //green tint
params.br, params.bg, params.b, 0.0, //blue tint
params.blr, params.blg, params.blb, 0.0); //black tint
mat4 adjust = mat4((1.0 - sat) * 0.2126 + sat, (1.0 - sat) * 0.2126, (1.0 - sat) * 0.2126, 1.0,
(1.0 - sat) * 0.7152, (1.0 - sat) * 0.7152 + sat, (1.0 - sat) * 0.7152, 1.0,
(1.0 - sat) * 0.0722, (1.0 - sat) * 0.0722, (1.0 - sat) * 0.0722 + sat, 1.0,
0.0, 0.0, 0.0, 1.0);
screen = clamp(screen * ((params.lum - 1.0) * 2.0 + 1.0), 0.0, 1.0);
screen = color * screen;
float sat_msk = (params.dulvibr > 0.0) ? clamp(1.0 - (SatMask(screen.r, screen.g, screen.b) * params.dulvibr), 0.0, 1.0) : clamp(1.0 - abs(SatMask(screen.r, screen.g, screen.b) - 1.0) * abs(params.dulvibr), 0.0, 1.0);
screen = mixfix_v4(screen, adjust * screen, sat_msk);
// Color Temperature
vec3 adjusted = wp_adjust(screen.rgb);
vec3 base_luma = XYZtoYxy(sRGB_to_XYZ(screen.rgb));
vec3 adjusted_luma = XYZtoYxy(sRGB_to_XYZ(adjusted));
adjusted = (params.luma_preserve == 1.0) ? adjusted_luma + (vec3(base_luma.r, 0.0, 0.0) - vec3(adjusted_luma.r, 0.0, 0.0)) : adjusted_luma;
adjusted = clamp(XYZ_to_sRGB(YxytoXYZ(adjusted)), 0.0, 1.0);
FragColor = vec4(moncurve_r_f3(adjusted, params.gamma_out + 0.20, 0.055), 1.0);
}
