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

43 lines
1,010 B
GLSL

// https://ieeexplore.ieee.org/document/7291452
// https://www.itu.int/rec/R-REC-BT.2100
// https://www.itu.int/pub/R-REP-BT.2390
// pq ootf: 100.0 * bt1886_eotf(bt709_oetf(59.5208 * x), 2.4, 1.0, 0.0)
//!PARAM reference_white
//!TYPE float
//!MINIMUM 0.0
//!MAXIMUM 1000.0
203.0
//!HOOK OUTPUT
//!BIND HOOKED
//!DESC transfer function (pq)
const float m1 = 2610.0 / 4096.0 / 4.0;
const float m2 = 2523.0 / 4096.0 * 128.0;
const float c1 = 3424.0 / 4096.0;
const float c2 = 2413.0 / 4096.0 * 32.0;
const float c3 = 2392.0 / 4096.0 * 32.0;
const float pw = 10000.0;
float pq_eotf_inv(float x) {
float t = pow(x / pw, m1);
return pow((c1 + c2 * t) / (1.0 + c3 * t), m2);
}
vec3 pq_eotf_inv(vec3 color) {
return vec3(
pq_eotf_inv(color.r),
pq_eotf_inv(color.g),
pq_eotf_inv(color.b)
);
}
vec4 hook() {
vec4 color = HOOKED_tex(HOOKED_pos);
color.rgb = pq_eotf_inv(color.rgb * reference_white);
return color;
}