dotfiles/mpv/shaders/hdr-toys/transfer-function/bt709_inv.glsl
2025-05-26 00:03:04 +10:00

30 lines
702 B
GLSL

// https://www.itu.int/rec/R-REC-BT.601
// https://www.itu.int/rec/R-REC-BT.709
// https://www.itu.int/rec/R-REC-BT.2020
//!HOOK OUTPUT
//!BIND HOOKED
//!DESC transfer function (bt.709, inverse)
const float beta = 0.018053968510807;
const float alpha = 1.0 + 5.5 * beta;
float bt709_oetf_inv(float V) {
return V < 4.5 * beta ? V / 4.5 : pow((V + (alpha - 1.0)) / alpha, 1.0 / 0.45);
}
vec3 bt709_oetf_inv(vec3 color) {
return vec3(
bt709_oetf_inv(color.r),
bt709_oetf_inv(color.g),
bt709_oetf_inv(color.b)
);
}
vec4 hook() {
vec4 color = HOOKED_tex(HOOKED_pos);
color.rgb = bt709_oetf_inv(color.rgb);
return color;
}