alex/slang-shaders
1
0
Fork 0
mirror of https://github.com/italicsjenga/slang-shaders.git synced 2024-11-22 15:51:30 +11:00
Code Issues Packages Projects Releases Wiki Activity

Update colorspace-tools.h

Browse source 
add some basic grayscale / luma conversions, fix up some style inconsistencies and add some informational comments about some of the color spaces.
This commit is contained in:
hunterk 2022-12-07 09:52:07 -06:00 committed by GitHub
parent bc2141a6fa
commit ea8683bc61
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 148 additions and 86 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

228
include/colorspace-tools.h
View file

@ -64,8 +64,8 @@ vec3 srgb_linear(vec3 x) {
#endif #endif
} }
vec3 linear_to_sRGB(vec3 color, float gamma){ vec3 linear_to_sRGB(vec3 color, float gamma)
{
color = clamp(color, 0.0, 1.0); color = clamp(color, 0.0, 1.0);
color.r = (color.r <= 0.00313066844250063) ? color.r = (color.r <= 0.00313066844250063) ?
color.r * 12.92 : 1.055 * pow(color.r, 1.0 / gamma) - 0.055; color.r * 12.92 : 1.055 * pow(color.r, 1.0 / gamma) - 0.055;
@ -77,8 +77,8 @@ vec3 linear_to_sRGB(vec3 color, float gamma){
return color.rgb; return color.rgb;
} }
vec3 sRGB_to_linear(vec3 color, float gamma){ vec3 sRGB_to_linear(vec3 color, float gamma)
{
color = clamp(color, 0.0, 1.0); color = clamp(color, 0.0, 1.0);
color.r = (color.r <= 0.04045) ? color.r = (color.r <= 0.04045) ?
color.r / 12.92 : pow((color.r + 0.055) / (1.055), gamma); color.r / 12.92 : pow((color.r + 0.055) / (1.055), gamma);
@ -90,117 +90,165 @@ vec3 sRGB_to_linear(vec3 color, float gamma){
return color.rgb; return color.rgb;
} }
//Conversion matrices /*------------------------------------------------------------------------------
vec3 RGBtoXYZ(vec3 RGB) [RGB TO GRAYSCALE / LUMA CODE SECTION]
{ ------------------------------------------------------------------------------*/
const mat3x3 m = mat3x3(
0.6068909, 0.1735011, 0.2003480,
0.2989164, 0.5865990, 0.1144845,
0.0000000, 0.0660957, 1.1162243);
// if you're already in linear gamma, definitely use this one ( Y = 0.2126R + 0.7152G + 0.0722B )
// the Rec. 709 spec uses these same coefficients but with gamma-compressed components ( Y' = 0.2126R' + 0.7152G' + 0.0722B' )
float luma(vec3 color)
{
return dot(color, vec3(0.2126, 0.7152, 0.0722));
}
// for digital formats following CCIR 601 (that is, most digital standard def formats)
// expects gamma-compressed components and doesn't look very good
// ( Y' = 0.299R' + 0.587G' + 0.114B' )
float luma_CCIR601(vec3 color)
{
return dot(color, vec3(0.299, 0.587, 0.114));
}
// SMPTE 240M; used by some transitional 1035i HDTV signals. Expects gamma-compressed components
// ( Y' = 0.212R' + 0.701G' + 0.087B' )
float luma_240M(vec3 color)
{
return dot(color, vec3(0.212, 0.701, 0.087));
}
// Same as Rec. 709 but with quick-and-dirty gamma linearization added on top
float luma_gamma(vec3 color)
{
color = color * color;
float luma = dot(color, vec3(0.2126, 0.7152, 0.0722));
return sqrt(luma);
}
/*------------------------------------------------------------------------------
[COLORSPACE CONVERSION CODE SECTION]
------------------------------------------------------------------------------*/
/* XYZ color space is a device-invariant representation that encompasses all color sensations that are visible to a person
with average eyesight. Y is the luminance, Z is quasi-equal to blue and X is a mix of the three CIE RGB curves chosen to be non-negative */
vec3 RGBtoXYZ(vec3 RGB)
{
const mat3x3 m = mat3x3(
0.6068909, 0.1735011, 0.2003480,
0.2989164, 0.5865990, 0.1144845,
0.0000000, 0.0660957, 1.1162243);
return RGB * m; return RGB * m;
} }
vec3 XYZtoRGB(vec3 XYZ) vec3 XYZtoRGB(vec3 XYZ)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
1.9099961, -0.5324542, -0.2882091, 1.9099961, -0.5324542, -0.2882091,
-0.9846663, 1.9991710, -0.0283082, -0.9846663, 1.9991710, -0.0283082,
0.0583056, -0.1183781, 0.8975535); 0.0583056, -0.1183781, 0.8975535);
return XYZ * m; return XYZ * m;
} }
vec3 XYZtoSRGB(vec3 XYZ) vec3 XYZtoSRGB(vec3 XYZ)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
3.2404542,-1.5371385,-0.4985314, 3.2404542,-1.5371385,-0.4985314,
-0.9692660, 1.8760108, 0.0415560, -0.9692660, 1.8760108, 0.0415560,
0.0556434,-0.2040259, 1.0572252); 0.0556434,-0.2040259, 1.0572252);
return XYZ * m; return XYZ * m;
} }
/* YUV is a color space that takes human perception into account, allowing reduced bandwidth for chrominance components,
as compared with a direct RGB representation. It includes a luminance component, Y, with nonlinear perceptual brightness,
and two color components, U and V. This colorspace was used in the PAL color broadcast standard and is the counterpart to
NTSC's YIQ colorspace. It is still commonly used to describe YCbCr signals. */
vec3 RGBtoYUV(vec3 RGB) vec3 RGBtoYUV(vec3 RGB)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
0.2126, 0.7152, 0.0722, 0.2126, 0.7152, 0.0722,
-0.09991,-0.33609, 0.436, -0.09991,-0.33609, 0.436,
0.615, -0.55861, -0.05639); 0.615, -0.55861, -0.05639);
return RGB * m;
return RGB * m; }
}
vec3 YUVtoRGB(vec3 YUV) vec3 YUVtoRGB(vec3 YUV)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
1.000, 0.000, 1.28033, 1.000, 0.000, 1.28033,
1.000,-0.21482,-0.38059, 1.000,-0.21482,-0.38059,
1.000, 2.12798, 0.000); 1.000, 2.12798, 0.000);
return YUV * m;
}
return YUV * m; /* YIQ is the color space used for analog NTSC color broadcasts, whereby Y stands for luma, I stands for in-phase and
} Q stands for quadrature, referring to the components used in quadrature amplitude modulation. The IQ axes exist on the
same plane as the UV axes from the YUV color space, just rotated 33 degrees. */
vec3 RGBtoYIQ(vec3 RGB) vec3 RGBtoYIQ(vec3 RGB)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
0.2989, 0.5870, 0.1140, 0.2989, 0.5870, 0.1140,
0.5959, -0.2744, -0.3216, 0.5959, -0.2744, -0.3216,
0.2115, -0.5229, 0.3114); 0.2115, -0.5229, 0.3114);
return RGB * m; return RGB * m;
} }
vec3 YIQtoRGB(vec3 YIQ) vec3 YIQtoRGB(vec3 YIQ)
{ {
const mat3x3 m = mat3x3( const mat3x3 m = mat3x3(
1.0, 0.956, 0.6210, 1.0, 0.956, 0.6210,
1.0, -0.2720, -0.6474, 1.0, -0.2720, -0.6474,
1.0, -1.1060, 1.7046); 1.0, -1.1060, 1.7046);
return YIQ * m; return YIQ * m;
} }
vec3 XYZtoYxy(vec3 XYZ) vec3 XYZtoYxy(vec3 XYZ)
{ {
float w = (XYZ.r + XYZ.g + XYZ.b); float w = (XYZ.r + XYZ.g + XYZ.b);
vec3 Yxy; vec3 Yxy;
Yxy.r = XYZ.g; Yxy.r = XYZ.g;
Yxy.g = XYZ.r / w; Yxy.g = XYZ.r / w;
Yxy.b = XYZ.g / w; Yxy.b = XYZ.g / w;
return Yxy; return Yxy;
} }
vec3 YxytoXYZ(vec3 Yxy) vec3 YxytoXYZ(vec3 Yxy)
{ {
vec3 XYZ; vec3 XYZ;
XYZ.g = Yxy.r; XYZ.g = Yxy.r;
XYZ.r = Yxy.r * Yxy.g / Yxy.b; XYZ.r = Yxy.r * Yxy.g / Yxy.b;
XYZ.b = Yxy.r * (1.0 - Yxy.g - Yxy.b) / Yxy.b; XYZ.b = Yxy.r * (1.0 - Yxy.g - Yxy.b) / Yxy.b;
return XYZ; return XYZ;
} }
/* CMYK--aka process color or four color--is a subtractive color model based on the CMY color model that is
used in color printing and to describe the printing process itself. C is for Cyan, M is for Magenta, Y is for
Yellow and K is for 'key' or black. */
// RGB <-> CMYK conversions require 4 channels // RGB <-> CMYK conversions require 4 channels
vec4 RGBtoCMYK(vec3 RGB){ vec4 RGBtoCMYK(vec3 RGB){
float Red = RGB.r; float Red = RGB.r;
float Green = RGB.g; float Green = RGB.g;
float Blue = RGB.b; float Blue = RGB.b;
float Black = min(1.0 - Red, min(1.0 - Green, 1.0 - Blue)); float Black = min(1.0 - Red, min(1.0 - Green, 1.0 - Blue));
float Cyan = (1.0 - Red - Black) / (1.0 - Black); float Cyan = (1.0 - Red - Black) / (1.0 - Black);
float Magenta = (1.0 - Green - Black) / (1.0 - Black); float Magenta = (1.0 - Green - Black) / (1.0 - Black);
float Yellow = (1.0 - Blue - Black) / (1.0 - Black); float Yellow = (1.0 - Blue - Black) / (1.0 - Black);
return vec4(Cyan, Magenta, Yellow, Black); return vec4(Cyan, Magenta, Yellow, Black);
} }
vec3 CMYKtoRGB(vec4 CMYK){ vec3 CMYKtoRGB(vec4 CMYK){
float Cyan = CMYK.x; float Cyan = CMYK.x;
float Magenta = CMYK.y; float Magenta = CMYK.y;
float Yellow = CMYK.z; float Yellow = CMYK.z;
float Black = CMYK.w; float Black = CMYK.w;
float Red = 1.0 - min(1.0, Cyan * (1.0 - Black) + Black); float Red = 1.0 - min(1.0, Cyan * (1.0 - Black) + Black);
float Green = 1.0 - min(1.0, Magenta * (1.0 - Black) + Black); float Green = 1.0 - min(1.0, Magenta * (1.0 - Black) + Black);
float Blue = 1.0 - min(1.0, Yellow * (1.0 - Black) + Black); float Blue = 1.0 - min(1.0, Yellow * (1.0 - Black) + Black);
return vec3(Red, Green, Blue); return vec3(Red, Green, Blue);
} }
// Converting pure hue to RGB // Converting pure hue to RGB
@ -291,20 +339,27 @@ const vec3 D9000KDS = vec3(0.90354,1.00000,1.31190);//8939K, 0.0114 Duv
//} //}
// --- sRGB --- // // --- sRGB --- //
vec3 XYZ_to_sRGB(vec3 x) { vec3 XYZ_to_sRGB(vec3 x)
{
x = x * mat3x3( 3.2404542, -1.5371385, -0.4985314, -0.9692660, 1.8760108, 0.0415560, 0.0556434, -0.2040259, 1.0572252 ); x = x * mat3x3( 3.2404542, -1.5371385, -0.4985314, -0.9692660, 1.8760108, 0.0415560, 0.0556434, -0.2040259, 1.0572252 );
x = mix(1.055*pow(x, vec3(1./2.4)) - 0.055, 12.92*x, step(x,vec3(0.0031308))); x = mix(1.055*pow(x, vec3(1./2.4)) - 0.055, 12.92*x, step(x,vec3(0.0031308)));
return x; return x;
} }
vec3 sRGB_to_XYZ(vec3 x) { vec3 sRGB_to_XYZ(vec3 x)
{
x = mix(pow((x + 0.055)/1.055,vec3(2.4)), x / 12.92, step(x,vec3(0.04045))); x = mix(pow((x + 0.055)/1.055,vec3(2.4)), x / 12.92, step(x,vec3(0.04045)));
x = x * mat3x3( 0.4124564, 0.3575761, 0.1804375, 0.2126729, 0.7151522, 0.0721750, 0.0193339, 0.1191920, 0.9503041 ); x = x * mat3x3( 0.4124564, 0.3575761, 0.1804375, 0.2126729, 0.7151522, 0.0721750, 0.0193339, 0.1191920, 0.9503041 );
return x; return x;
} }
// --- Jzazbz --- //{ /* Jzazbz is a color space designed for perceptual uniformity in high dynamic range (HDR) and wide color gamut (WCG) applications.
vec3 XYZ_to_Jzazbz(vec3 XYZ) { It is conceptually similar to CIE Lab but is considered more "modern". As compared with Lab, perceptual color differences are
predicted by Euclidean distance, it is more perceptually uniform and changes in saturation or lightness produce less shifts in hue
(i.e., increased hue linearity). Jzazbz and JzCzhz are used by ImageMagick and not much else. */
vec3 XYZ_to_Jzazbz(vec3 XYZ)
{
float b = 1.15; float b = 1.15;
float g = 0.66; float g = 0.66;
vec3 XYZprime = XYZ; vec3 XYZprime = XYZ;
@ -326,14 +381,18 @@ vec3 XYZ_to_Jzazbz(vec3 XYZ) {
return Jzazbz; return Jzazbz;
} }
vec3 Jzazbz_to_JzCzhz(vec3 Jzazbz) { /* The polar version of Jzazbz */
vec3 Jzazbz_to_JzCzhz(vec3 Jzazbz)
{
float Cz = sqrt(Jzazbz.y*Jzazbz.y + Jzazbz.z*Jzazbz.z); float Cz = sqrt(Jzazbz.y*Jzazbz.y + Jzazbz.z*Jzazbz.z);
float hz = atan(Jzazbz.z,Jzazbz.y); float hz = atan(Jzazbz.z,Jzazbz.y);
vec3 JzCzhz = vec3(Jzazbz.x,Cz,hz); vec3 JzCzhz = vec3(Jzazbz.x,Cz,hz);
return JzCzhz; return JzCzhz;
} }
vec3 JzCzhz_Normalize(vec3 JzCzhz) { vec3 JzCzhz_Normalize(vec3 JzCzhz)
{
JzCzhz.x = JzCzhz.x*56.91964; JzCzhz.x = JzCzhz.x*56.91964;
JzCzhz.y = JzCzhz.y*40.05235; JzCzhz.y = JzCzhz.y*40.05235;
JzCzhz.z = (JzCzhz.z+2.761)/5.522; JzCzhz.z = (JzCzhz.z+2.761)/5.522;
@ -343,19 +402,22 @@ vec3 JzCzhz_Normalize(vec3 JzCzhz) {
return JzCzhz; return JzCzhz;
} }
vec3 JzCzhz_Denormalize(vec3 JzCzhz) { vec3 JzCzhz_Denormalize(vec3 JzCzhz)
{
JzCzhz.x = JzCzhz.x/56.91964; JzCzhz.x = JzCzhz.x/56.91964;
JzCzhz.y = JzCzhz.y/40.05235; JzCzhz.y = JzCzhz.y/40.05235;
JzCzhz.z = JzCzhz.z * 5.522 - 2.761; JzCzhz.z = JzCzhz.z * 5.522 - 2.761;
return JzCzhz; return JzCzhz;
} }
vec3 JzCzhz_to_Jzazbz(vec3 JzCzhz) { vec3 JzCzhz_to_Jzazbz(vec3 JzCzhz)
{
vec3 Jzazbz = vec3(JzCzhz.x,JzCzhz.y*cos(JzCzhz.z),JzCzhz.y*sin(JzCzhz.z));; vec3 Jzazbz = vec3(JzCzhz.x,JzCzhz.y*cos(JzCzhz.z),JzCzhz.y*sin(JzCzhz.z));;
return Jzazbz; return Jzazbz;
} }
vec3 Jzazbz_to_XYZ(vec3 Jzazbz) { vec3 Jzazbz_to_XYZ(vec3 Jzazbz)
{
float d0 = 1.6295499532821566 * pow(10.0,-11.0); float d0 = 1.6295499532821566 * pow(10.0,-11.0);
float d = -0.56; float d = -0.56;
float Iz = (Jzazbz.x + d0) / (1 + d - d * (Jzazbz.x + d0)); float Iz = (Jzazbz.x + d0) / (1 + d - d * (Jzazbz.x + d0));