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Rise of the Tomb Raider cave exit effect

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Hello everyone,

A while ago I was playing Rise of the Tomb Raider and noticed a really nice effect when Lara is near a cave's exit: the environment outside lerp from very bright to the correct luminance when she is out. An example can be seen here: https://i.kinja-img.com/gawker-media/image/upload/peafu9itvcrf8iasfibd.gif
I'm especially interested in the 'inside the cave' part.

I'm really curious about how it can be implemented: is it a tone mapping or a bloom tweak? Or maybe neither of them?

Does someone know something about it or have worked on something similar?
Anything is well accepted! Thank you.

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So basically using Reinhard I could achieve the same effect?

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So basically using Reinhard I could achieve the same effect?

You can't. You will need 'linear exposure' + 'un-linear tonemapping'. Reinhard is only a method for tonemap.

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So basically using Reinhard I could achieve the same effect?

Depending on which version, yes.
The basic version (which maps infinity to white) is:
color = color/(1+color);
And the version with an adjustable white point is:
color = (color*(1+color/(white*white)))/(1+color);
Either of these can be augmented to include an exposure modification right before tone-mapping, e.g.:

color *= exposure;                                 // Exposure
color = (color*(1+color/(white*white)))/(1+color); // Reinhard
return pow(color, 1/2.2);                          //linear -> sRGB approximation

If modelling a real physical camera system, you'd compute the exposure multiplier from the camera's ISO, F-stop/aperture and shutter time settings.
If using auto adaptation, you might use the average scene luminance to pick an exposure value that will center the image around middle grey:
e.g. exposure = 0.18/averageLuminance; or exposure = 0.18/exp2( averageLog2Luminance );
Or if manually tweaking your scenes, you can manually set the exposure variable to whatever you like.

However, Reinhard is a pretty unpopular tonemapping curve for games these days. Try some of these instead: http://filmicgames.com/archives/75

You will also need a bloom effect to get the over-exposed regions of the image to bleed into the darker surroundings.

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So basically using Reinhard I could achieve the same effect?

Depending on which version, yes.
The basic version (which maps infinity to white) is:[font='courier new', courier, monospace]color = color/(1+color);[/font]
And the version with an adjustable white point is:[font='courier new', courier, monospace]color = (color*(1+color/(white*white)))/(1+color);[/font]
Either of these can be augmented to include an exposure modification right before tone-mapping, e.g.:
color *= exposure;                                 // Exposure
color = (color*(1+color/(white*white)))/(1+color); // Reinhard
return pow(color, 1/2.2);                          //linear -> sRGB approximation
If modelling a real physical camera system, you'd compute the exposure multiplier from the camera's ISO, F-stop/aperture and shutter time settings.
If using auto adaptation, you might use the average scene luminance to pick an exposure value that will center the image around middle grey:
e.g. [font='courier new', courier, monospace]exposure = 0.18/averageLuminance;[/font] or [font='courier new', courier, monospace]exposure = 0.18/exp2( averageLog2Luminance );[/font]
Or if manually tweaking your scenes, you can manually set the exposure variable to whatever you like.

However, Reinhard is a pretty unpopular tonemapping curve for games these days. Try some of these instead: http://filmicgames.com/archives/75

You will also need a bloom effect to get the over-exposed regions of the image to bleed into the darker surroundings.

OK, when I said Reinhard I meant, wrongly, the auto exposure technique and the operator itself. Maybe because they are on the same paper. Better, I also learned this, thank you very much!
And thank you for the link I can't wait to experiment!

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So basically using Reinhard I could achieve the same effect?

You can't. You will need 'linear exposure' + 'un-linear tonemapping'. Reinhard is only a method for tonemap.
Sorry I almost forgot to thank you too! Could you elaborate on the un-linear tonemapping requirement?

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Sorry I almost forgot to thank you too! Could you elaborate on the un-linear tonemapping requirement?

The purpose of linear auto-exposure (linear AE) is to adjust the whole brightness level, in a wide dynamic range. It is very important at the first place because that human eye is much more sensitive to the brightness than the color/hue. The point here is: NEVER talk about tonemapping before you get some proper exposure.

In the meanwhile, the unlinear tonemapping’s purpose is to adjust the perception of your eye for color and hue, in a much more narrow dynamic range, given a specific over-all brightness level. The common standard tonemapping methods include reinard?filmic?uncharted2?aes etc. At most time, the quality of tonemapping is very subjective, and it is all about personal’s preference. Compared with AE op, the operations of dynamic range compression and contrast adjustment are often involved in tonemapping. So we often call it as an ‘unlinear’ operation.

Edited by neoragex

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Sorry I almost forgot to thank you too! Could you elaborate on the un-linear tonemapping requirement?

The purpose of linear auto-exposure (linear AE) is to adjust the whole brightness level, in a wide dynamic range. It is very important at the first place because that human eye is much more sensitive to the brightness than the color/hue. The point here is: NEVER talk about tonemapping before you get some proper exposure.

In the meanwhile, the unlinear tonemapping’s purpose is to adjust the perception of your eye for color and hue, in a much more narrow dynamic range, given a specific over-all brightness level. The common standard tonemapping methods include reinard?filmic?uncharted2?aes etc. At most time, the quality of tonemapping is very subjective, and it is all about personal’s preference. Compared with AE op, the operations of dynamic range compression and contrast adjustment are often involved in tonemapping. So we often call it as an ‘unlinear’ operation.
Very interesting, thank you very much!