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TOPIC: "reverse tonemapping"?

"reverse tonemapping"? 2 years 8 months ago #21

Minimal research resulted in the finding of this:
Slope = 0.98;
Toe = 0.3;
Shoulder = 0.22;
BlackClip = 0;
WhiteClip = 0.025;

Theses seem to be the default tonemapping values for UE4. Haven't tried these myself, but will check back when I have.

EDIT:
Can confirm, these values look great!

(yes the light is supposed to be white)

Will continue testing.

EDIT 2:
Fixed the overblown lighting, forgot that I had multiplied the different blur passes to make them brighter :D

Colored light screenshot:
Last Edit: 2 years 8 months ago by NoMansReshade.
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The following user(s) said Thank You: luluco250

"reverse tonemapping"? 2 years 8 months ago #22

Any ideas on how we could reduce hue shifting?

Bright colors lose a lot of their precision (for obvious reasons), you can see how the bloom on the building shifts between yellow and red:


Perhaps there is a way to preserve the hue from the LDR image and reapply it to the HDR one?

Also adaptation seems to work better with multiplying just bloom, not actually using it as exposure in the tonemapping function (might be fixable with getting the adaptation from HDR + bloom, not just HDR alone, but that'd require an extra texture).

Edit:
Also, exp() is very useful for adapting the HDR texture.
Likes to reinvent the wheel.

My shaders repository: www.github.com/luluco250/FXShaders
Last Edit: 2 years 8 months ago by luluco250.
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"reverse tonemapping"? 2 years 8 months ago #23

I have encountered some of the problems you describe, however, I fixed them by just reducing the saturation of the bloom (hacky, I know.) Regardless, you may want to take a look at this: www.bulletforge.org/u/misaki-rindou/p/hl...rce-hue-shift-effect (The HLSL one)

It seems pretty complicated for such a simple task, unfortunately. It would also seem like the bloom is always about 5 hue shifts below what it needs to be... As to how we fix this, I'm not entirely sure. Although, I'm pretty sure it has something to do with the tonemapping algorithm.
Last Edit: 2 years 8 months ago by NoMansReshade.
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"reverse tonemapping"? 2 years 6 months ago #24

Spent some time inversing Hables operator...enjoy :)
y = ((0-((x+E/F)*B-C*B))-sqrt((((x+E/F)*B-C*B)*((x+E/F)*B-C*B))-4*((x+E/F)*A-A)*((x+E/F)*D*F-D*E)))/(2*((x+E/F)*A-A))
This was pretty fun to find the inverse. It needed me to relearn alot of stuff...never thought I'd use the quadratic formula again...
Last Edit: 2 years 6 months ago by MeatSafeMurderer.
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"reverse tonemapping"? 2 years 5 months ago #25

Hey bro, i want to use this thing right now badly, mind sharing your files? I don't have slightest idea how to handle things posted here, but results are amazing!
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