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TOPIC: Linear Space vs. Gamma Space, Reshade Innovation

Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #1

So i love the Witcher 3 but the notorious downgrade is still bothering me after all this time, and the mod "tools" we've been given are a joke. The biggest issue with the release version imo is the degradation of lighting accuracy.

I know the lighting of the release version uses a Gamma space rendering pipeline as opposed to the much preferred Linear space pipeline. I'm also aware that such a decision is inherently implemented as part of the rendering pipeline and can't be "changed" without access to the engine itself (does anyone have any ideas as to how we could fake linear lighting via reshade?). Having said that, i also would've wrongly assumed that features such as ambient occlusion and bloom had to be pre-written in the game's post-processing pipeline and couldn't be implemented via reshade. I mean right now, MartyMcFly is working on a really impressive implementation of pseudo global illumination that can have some really convincing results, which i literally never would've imagined is possible with reshade. We also have some really creative people working on ways to try to implement TAA, which again i thought was not possible via reshade.

For that reason, i realize there are a few people on this forum who may be aware/capable of possibilities that i wouldn't even have thought was possible enough to ask for. So basically my question is (for the sake of discussion and hopefully innovation); does anyone have any ideas for what could be done (with reshade) to try and claw our way back to the visual fidelity seen in the pre-release gameplay of TW3? i know the 2013 footage is literally impossible without access to the engine since the assets themselves are completely different, but the e3 2014 gameplay is close enough to release in that respect that i wouldn't be surprised if the talented ladies and gentleman on this forum could get there.

Sorry for the long post btw, just trying to be clear/descriptive.
Last Edit: 10 months 1 week ago by SandyCheeks.
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #2

Gamma/linear space just affects the way the lighting looks and the entire ToD stuff of TW3 is tweaked to look good with their chosen pipeline so force-changing that would fuck everything up and you'd have to redo the entire settings for skycolor, light stuff etc.
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #3

You're absolutely right about how it would effect the overall image and how reliant the settings are on tod, but i've worked on lighting mods, and literally every lighting mod anyone has made for the game is done by changing various env parameters. So having to go and make changes based on the different appearances of linear vs gamma is to be expected.

Also (as im certain you're aware of) linear lighting does more than just change how it looks in the context of being "different"; instead it changes how things look in the context of being objectively better, due to the less harsh highlights and more natural drop-off of light hitting a surface.
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #4

like i was saying in my first post though, clearly we don't have the ability (using post process shaders) to retroactively go into the rendering pipeline and alter it in such a way. However, i wouldn't be surprised at all if you, or someone close to you in skill, would be able to kind of "fake" the appearance/visual effect that a linear space pipeline would produce (even if it's not a perfect emulation).
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #5

You can use the
button to edit your posts afterwards. Have seen you double-posting on multiple occasions so I figured I'd let you know, keeping the forums clean and all :)

Changing gamma->linear without adjusting the game's settings will only fuck the image up. Re-adjusting those will make them look more or less the same. It's no magical recipe that will make the game look much better, it will mostly only adjust how saturated point lights are and how light falls off based on angle of surface to light sources. Look here:

http://static1.squarespace.com/static/525ed7ade4b0924d2f499223/t/575f42e327d4bdc48f2261e4/1465860851928/An+image+comparing+gamma+and+linear+pipelines

As you can see, both ways look valid. Based on tonemapping and/or lighting settings like roughness or metallic (if TW3 uses PBR terms which I don't know) one can look like the other. There's no way to change or fake this with ReShade in any way. As you're most likely after photorealism, use the regular tools you have available and tweak so it looks best to you and don't worry about such terms.
Last Edit: 10 months 1 week ago by Marty McFly.
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The following user(s) said Thank You: turgor128

Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #6

Haha noted, thanks for the tip :lol:

" how saturated point lights are and how light falls off based on angle of surface to light sources" is a huge contributor to overall image quality in this regard, so while i know the change wouldn't be the equivalent of some wand waving "Quality" spell, i disagree with your assesment that it couldn't make the game look substantially better with the right tweaks...

I have, up until now, been using the tools at my disposal to get an image that i like, but there are areas such as this one that I've felt are unattainable given our current shaders. Again just to reiterate, i have no idea how this would be done in practice but like i said originally, there were many things you guys have done that i wouldn't have thought could be done before.

Similar to how i asked you about depth based bloom; i'm pretty happy with all the current bloom shaders out there... but there's always room for improvement so i asked if anything like that was possible :)

Anyway thanks again for the responses, your insight is always valued. After seeing what you're able to do with your IL implementation though , i'm shocked you don't think anything can be done here. Hopefully someone else can think of something.
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 1 week ago #7

Using a different lighting system doesn't make the game look better. It's not linear > gamma, these're both valid ways to calculate lighting. With ReShade, such things you ask for are impossible to even fake. Directional lighting is basically any function on the angle of surface towards the light source. It'd be easy to translate linear lighting to gamma if it was one light source, static scene, uniform values and so on. With everything in the game, there's no way to reconstruct the actual lighting intensity on a surface, let alone calculations that reach further.
Last Edit: 10 months 1 week ago by Marty McFly.
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Linear Space vs. Gamma Space, Reshade Innovation 10 months 5 days ago #8

Didn't CDPR use a forward render system that didn't work in open world and then switched to a deferred render system? :S
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