Renderer: High quality inverse tonemapping for SDR on HDR.

[Quackdoc]

Apologies, I am quite new to hyprland so I may have missed some configurations.

Describe the feature

It would be nice if hyprland supported a higher quality inverse tonemapping solution

Why would it be beneficial

Currently enabling hyprland's always on HDR often results in rather not great SDR application quality. Even configuring display settings below, it can be very hard, if not impossible to make HDR look decent. Colours often look washed out. black levels rarely line up, even when setting min luminance, and it's hard to strike the right balance of saturation in colours.
Related issues are:
#10264
#10950

These issues are not limited to any one display. Having a better tonemapper would be quite appreciated.

sdr_min_luminance
sdr_max_luminance
min_luminanc
max_luminance
max_avg_luminance
sdrbrightness
sdrsaturation

To put into perspective, I found that using the below MPV cmdline to produce better results in both watching normal videos, but also for general use (tested by capturing the SDR as a screen recording then playing it back) I have played around with cm.glsl and I do think implementing a better tonemapper in there is a viable solution. I haven't quite figured it since I wanted to port bt.2446a https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2446-1-2021-PDF-E.pdf (page 10 in the document, page 24 in the pdf itself) but that operates on YCbCr which may be a bit expensive to compute and im still learning the color management chain.

Note: Many users will find that using a pure 2.2 for all srgb applications will look better in most cases now. I think this should be configurable (if this could be on a per window basis then defaulting to pure 2.2 would be a safe choice, for now I just modified ~/.config/hypr/shaders/CM.glsl)

[HDRify]
vo=gpu-next
gpu-api=vulkan
gpu-context=waylandvk
target-colorspace-hint
target-trc=pq
target-prim=bt.2020
inverse-tone-mapping
target-peak=400
tonemapping=bt.2446a