Hi, I’m looking for help with a glsl shader. This is a HDR tonemapping shader for MPV (open source video player) that is capable of using glsl shaders. I want to combine `float a`

and `float b`

to get `I2`

but I have no idea how to implement it.

I want the low information (like srgb 0-180) from `float a`

and the high information (like srgb 180-255) from `float b`

to get `I2`

. So like legs `from a`

and torso `from b`

I’m a noob in glsl but I will try out any suggestions.

Any help would be appreciated

This is the shader

```
vec3 tone_mapping_ictcp(vec3 ICtCp) {
float a = Y_to_ST2084(curve(ST2084_to_Y(ICtCp.x) / L_sdrr, 250 / L_sdrr) * L_sdrr);
float b = Y_to_ST2084(curve(ST2084_to_Y(ICtCp.x) / L_sdrr, 500 / L_sdrr) * L_sdrr);
?? float I2 = ?;
ICtCp.yz *= mix(1.0, min(ICtCp.x / I2, I2 / ICtCp.x), sigma);
ICtCp.x = I2;
return ICtCp;
}
```

For demonstration purposes I color coded the picture. The green should come from `float a`

(dark/low luminance) and the yellow should come from `float b`

(bright/high luminance)