Godot: Filmic tone mapping does not work correctly

[Linko-3D]

Godot 3.0.2

Windows 10, GTX 1070

I have compared Filmic with Blender and the tone mapping in Godot with an HDRI map and Godot is not correct, the result is almost the same as the Linear tone mapping. I have used it in a new project with all the default settings (so the panorama is in HDR).

Here are the two software with Filmic, at the left it's Blender with the correct tone mapping:

You can download the .HDR map to test it here: https://hdrihaven.com/hdri/?c=skies&h=kiara_1_dawn

[CptPotato]

~The main (but not the only) problem is that you can't set the whitepoint high enough because Godot is limiting the value to a maximum of 16.0 - which in this implementation is definitely not enough to soften the highlights (it basically looks like there's no tonemapping).~ edit: see my next comment

Tonemapping and Bloom in general is implemented pretty badly in my opinion. None of the Tonemapping operators provides a high enough whitepoint, the ACES operator plain out ignores it and the implementations of all of them inside the shaders look very copy-pasty.

Bloom is also blended in a way that doesn't make a lot of sense to me. Internally it uses HDR but it's blended after the tonemapping with other blending modes like "soft light", loosing all the benefit from HDR and taking away the "physically based" aspect.

I once changed those things in a test and got results that I much preferred:
built-in filmic tonemapper vs custom ACES tonemapper w/ better bloom

I might create an issue collecting and addressing those problems but I'm having trouble getting it all together without requiring to change large parts about the shader.

[volzhs]

so... #20096 fixed this issue? or is there something to be done? cc @CptPotato

[CptPotato]

20096 fixes a related issue. Revisiting this one, I think my initial thought was wrong (about the whitepoint being too low).

It seems like the overexposure is caused by the way glow is blended with the image and it's unrelated to the whitepoint value (if you turn off glow it looks a lot more like you'd expect). So I guess this is more of an issue with the blending modes.

I thought about adding one or two new blending modes that are physically based and would not have this problem but these are not part of the PR mentioned above.

[volzhs]

Thanks for the explanation. :smiley:

[tinmanjuggernaut]

I'm experiencing this same issue.

Godot 3.1.1 and 3.2.dev.custom_build.df17cf0
Windows 7/64
Intel HD 4400
Glow is off.
Project: 3D materials demo with items hidden, rotate to look at the sun.

On the right of the image below are all four tone mapping modes in Godot. The HDR is a little underexposed, so the last one is Filmic w/ exposure at 2. The sky is blown out in all.

On the left is blender showing the default oversaturated and blown out mode, filmic mode, and filmic w/ light strength at 2. The latter two being what I would hope to see in Godot. Is there a setting I need to turn on or off?

Color representation looks fine in Godot (though the sky might be a little oversaturated - not shown here), but the tone mapping does not look fine. Instead of tonemapping, it is clipping.

Edit: Clarification

[CptPotato]

Increase the white value, that should do the trick.

[tinmanjuggernaut]

Indeed it does. I bumped it up and got the expected results. Thank you sir!

[Linko-3D]

The maximum white value should be detected automatically like other engines do.