Request: Customizable Color Space

[SlyCoop91]

Hi Stride Team,

I've been watching videos relating to how to add stuff like fog, materials, etc. to a game project since I wanted to try game development about a year or so ago. That is when I stumbled on a video called "Real-Time Samurai Cinema: Lighting, Atmosphere, and Tonemapping in Ghost of Tsushima", and this made me very interested in creating my own color spaces like in Unreal Engine. This made me research on what game engines have a similar working color space like UE's color space, but I found none. That is when I decided - upon joining your Discord - to put in a request through Github.

As seen when looking at UE's working color space, a small menu pops up with a tab containing a variety of color spaces you can choose from, including one called Custom. Choosing Custom allows the user to definite the chromaticity coordinates for red, blue, green, and the White Point. This will allow users to have a more control and flexibility with color representation of images and a scene. Here are a few examples of what it looks like in Unreal Engine:

I hope this gets added to Stride in the future. This could possibly help make Stride one-step closers to being on the level of Unreal Engine and other engines of the same caliber.

[Doprez]

Is the same as the post processing effect that exists in the GraphicCompositor?

[SlyCoop91]

I hope so. As I said above, the Custom already exists, just it is not currently exposed in Stride. Currently I'm improving and refactoring some of the relevant parts in an ongoing PR that I want to finish soon. Maybe then it would be easier to look into this. In the meantime, I'll look into how one can define custom color spaces in DXGI.

Good luck with all of that. Also, if you would like, I can help location the chromaticity coordinates for any predefined color spaces alongside Custom. All I will need is a name for it, and I will go look for them.

[SlyCoop91]

I hope so. As I said above, the Custom already exists, just it is not currently exposed in Stride. Currently I'm improving and refactoring some of the relevant parts in an ongoing PR that I want to finish soon. Maybe then it would be easier to look into this. In the meantime, I'll look into how one can define custom color spaces in DXGI.

I was scrolling through the internet and found this (https://advances.realtimerendering.com/s2021/jpatry_advances2021/index.html#/92). It talks about something called a Rayleigh Color Space, so I am unsure if this could be considered as part of the customizable color space this discussion talks about. Or this could be something else entirely for the engine that just uses Color Space as its name. What is your opinion?

[Ethereal77]

It seems a custom color space they are using to better represent the colors in their atmospheric scattering, which is why it mentions Rayleigh coefficients, but I'd need to read it further to know more.

While interesting, this is unrelated to our conversation, which is about using custom color spaces for presentation.

Here Rayleigh is referring to the atmospheric scattering, which usually is computed by modelling the Rayleigh scattering (how light scatters in the atmosphere when hitting particles at molecular level) and the Mie scattering (how light is scattered when hitting particles the size of dust or water droplets).

[SlyCoop91]

It seems a custom color space they are using to better represent the colors in their atmospheric scattering, which is why it mentions Rayleigh coefficients, but I'd need to read it further to know more.

While interesting, this is unrelated to our conversation, which is about using custom color spaces for presentation.

Here Rayleigh is referring to the atmospheric scattering, which usually is computed by modelling the Rayleigh scattering (how light scatters in the atmosphere when hitting particles at molecular level) and the Mie scattering (how light is scattered when hitting particles the size of dust or water droplets).

Thanks for telling me. I was unsure if this also fits with the topic of a custom color space since it also has "color space" in that slide's name. Do you think I should delete that post?

[Ethereal77]

Don't delete it. It serves for reference for other people that may want to know more. That's the beauty of the Internet.

Take into account that in graphics and rendering, color space refers to a mathematical form of expressing colors (encoding colors in a vector space). There are many color spaces, and you can define your own (as you can see in those slides). You can, for example, get a color in a color space, anc convert it to another while you operate on it, then convert it back or to a third one, etc. That's what I think they are speaking of in the slide.

With that in mind, the conversation we were having is about configuring an output color space specifically for presenting to the screen (or to a texture, I suppose). That's what I believe the Unreal Engine is doing with that color space configuration you showed in the OP.
If anyone is more knowledgeable about color spaces or the Unreal Engine, please chime in.