Extended Global Fog (Unity5)

Hi Guys,
I decide to share my modification of the global fog image effect that comes with Unity5, since unity lacking a free good looking fog.
I extend it by adding some more option to control the global fog, also with fog scattering based from Preetham/Hoffman that scattered all across the net with all the parameter exposed in the inspector . Also keep in mind that i'm not a programmer so maybe my code are sucks or the result are incorrect
Also i believe there's a better way to control the shader conditional, but yeah i'll try to update it if i made some changes .
And if someone made a changes and willing to share it the community, just let me know i'll put it on the first post.
Note : the built in fog Color also affecting the Final fog Color.
Update: 08262016 you can get update for 5.4 in this post

Spoiler: Screenshot

 

This is looking great! Just one question: does the scattering work with multiple lights? I've seen a couple of similar approaches but it's always just for one directional light.

 

Sorry this one only support one directional light.
And i believe it's possible to support multiple lights in Unity5 via Compute buffer.

 

That's really beautiful! You, Sir, are amazing for sharing this with us!

 

Hi rea, it includes only script file, no shader file?
[Edit]
I do have Preetham code in glsl, so you mean we can implement it by our own, right?

By the way, I think the scattering fog supposes to support only 1 directional light as sun only.

 

Some planets have more than one sun...

 

Damn....i'm being stupid....sorry guys,
shader added.
it's fixed now please redownload and let me know how it goes

 

No problem rea. Thanks for sharing anyway

I'm working my own version of scattering fog. Actually after i look through the code of Scrawk's Atmospheric image effect project, it is easier than i thought.

 

you're welcome, btw why not use the same scattering that you used for uSky? it would make the fog match the sky color perfectly

 

Hmm it's possible but gonna be so expensive since you'll have to calculate the scattering twice from two suns, except if you implement a very simple and fast scattering for multiple lights

 

Of course, I will implement it with uSky.

 

Hi there,
I am getting the following error:

Assets/Standard Assets/Effects/ImageEffects/Scripts/GlobalFog.cs(9,23): error CS0246: The type or namespace name `PostEffectsBase' could not be found. Are you missing a using directive or an assembly reference?

 

You need to import that file from Unity standard package "Effect", inside has PostEffectsBase.cs file.

 

@rea,
I think you try to modify Preetham/Hoffman code to get the effect you want. However I'm not quite understand it.
I'm still grateful that you have shared it, I want to share something else here. I ported a 99.9% pure Preetham/Hoffman physical day sky codes directly for Unity 5 skybox shader, I think I got the default value pretty close to real sky color. This shader has not been optimised. People may check it out for learning purpose or implement it as a base for their own fog.
Keep in mind that it is just for only day sky, if you want some sunset color, you may need to modify it.

To use it, just create a new material and assign this shader, then apply it to Lighting skybox.
[Edit]
This skybox shader is default in linear color space.

[Edit]
Fixed the shader for PC

 

Awesome luckymouse ,
yeah actually there's still some stuff that confuse me in the code that i use, especially the world scale value

 

@Luckymouse : I got black sky using your shader

 

I have no problem, are using unity 5, right? does the scene have any directional light ?

 

yes and yes

 

Strange. I checked compiled code, seems everything fine. So should be working on window.(i'm on Mac)
Any error message from shader?

[Edit] Try this attached project file
[Edit] Deleted

 

Nope no error, also got black sky with your project. This is weird....

 

Black everything here also.

 

I found out one of the reason why this shader get black in PC, All the const need to change to static const .
so It won't got pitch black, but the sky color is still very dark by the default value.
Still checking whats wrong....
However it works all fine on Mac, so strange.

 

Ok, beside the issue above, also it seems the totalRayleigh(float3 lambda) function can not get the correct value on PC,
I did a quick hack to return the final value. This attached shader will work on PC, Tested on PC. I replaced the early posted file as well.

 

what happened to my skybox?
before: after

 

@rea in your pictures, the skybox seems visible through the fog, and your settings show that you checked "Affect Sky Box".
For some reason, even if I mimic your settings, the skybox always get occluded by the fog. I can only see the fog, it's colors and scatering. Its beautifull but your pics are even more so, since you can actually see the clouds...
Any ideas why my (and I supose the guy above) skybox gets occluded?

 

set the fog intensity in lighting tab to a very low value and disable distance fog

 

Thanks @rea, that solved it. I hadn't realized how much impact the built in fog settings had on your extended one. Sorry to bother again but one last question:
The sunrises look just like they would on Earth, but say I want a more blue-ish or green-ish sunrise, as if it was a alien sky... can I do that just by messing with the settings of the Extended (or built in) fog? Or those colors are hard coded?

 

Thanks for sharing, but I am unable to reproduce the nice bluish mountains in the distance. Would you be so kind to post a simple example scene with some terrain (just a bump will do) which shows the same effects as in the screen shots you posted?

 

The blue mountains are the fog. The fog is blue.

 

That is not the way it works, or should work anyway.

Blue wavelengths travel gets filtered out less by the atmosphere than red and green. So the further away an object is, the more blue it appears. This phenomenon is called Rayleigh Scattering, and since that effect is included in this shader, I assume it makes a correct approximation of it and not just adds blue fog like you mentioned.

 

So very true, the problem if i ignore the fog settings in the lighting tab you gonna get double fog. Since the default fog cannot be turned off if we want to use Global fog. Not sure if this behaviour are changed by unity in the latest version.

 

Interesting. This is a not-so-nice Unity limitation. Can someone from Unity jump in and provide a workaround for this, if possible?

 

or....you can just set the fog color to black in the lighting tab (not sure if it's a good idea or not)

it's possible just play around with the turbidity , world scale, and rayleigh settings. start with zero value would make it easier.

 

I just had a look at it again and it appears that the global fog does not use the default fog density, but it does use its color. I think this is pretty weird and goes against any form of object oriented logic. Using Unity 5.0.1p1

Unity: Simple colored fog really doesn't fit in a physically based pipeline. See feature request here:
http://feedback.unity3d.com/suggestions/physically-based-atmospheric-scattering-rayleigh-mie-1

 

Yeah physical based fog should be an option in the built in fog settings, not as an image effects

 

@rea,
Why not modify the build in fog shader also?

 

Ehh is that even possible?

Well this is sucks @.@

 

Not sure if this is the solution, but this could be it:
(scroll to Custom Fog with Final Color Modifier) http://docs.unity3d.com/Manual/SL-SurfaceShaderExamples.html
and
http://www.software7.com/blog/unity-custom-fog-shader-on-windows-phone-8/

 

Ah..for that you need to edit all the shaders in your project

 

Damn.

 

well except if Unity built in Fog function are already exposed somewhere

 

Yeah, I tried looking for that but couldn't find anything.

 

Wait, if you turn off distance fog then it doesn't use the build in fog at all, right? If you then set the global fog high enough, you could achieve a similar effect. Then you have total control over the color, ditch the build in fog color fetch and use your own. Could that be implemented?

 

Hi Rea,
funny, i was exactly looking for that fog http://forum.unity3d.com/threads/he...g-shader-or-image-effect.320945/#post-2081589
fortunately you did a good job, really...
the only little improvement i could wish is a general shadowing of the scene and a desaturation due to ligh loss.
looks better with a little DOF effect tough.

i have a little problem with directionnal lights : they are visible through trees foliage , odd.

thanks again for your great work, almost perfect

 

can you explain more about this, some images and sample would help

can you post some screenshot of this?

 

Is there a way to draw the scattering highlight behind objects instead of in front?

 

Yes, the Mie scattering can be block by the depth (Z-Buffer) value.

modify the rea's shader line #263 :

Code (CSharp):

1.         float3 betaMTheta = float3(betaM * mPhase).xyz * saturate( dpth - 0.5 );

(dpth - 0.5) mean blocked from half of the depth.
(dpth - 1.0) mean blocked everything, no scattering behind the mountain.

You can make a slider to control this value.
Hope it helps.

 

@rea
ok, i just took a screenshot of a scene, then blended with the zbuffer (or kinda) to obtain my ideal fog.
as you see in the attached image, my good fog looks almost like yours excepted that ideally, the fog should globally darken the scene and desaturate colors (as well as smooth shadows but that's another trick).
fog also should blur shapes (i guess i can do that with DOF)

the problem i have with lights is that they show though foliage instead of being altered by scattering. (see pic)

thanks again for the good work

 

Oh hey i was looking for this, do you mind if i add it to the extended fog?

The first one is easy actually but the blur pass would make the fog bit more expensive, the second one i'm still don't get it.
You mean like all the light are scattered by the fog or glowing/blooming under the fog?
Note : Image from Nvidia demo