Lux – an open source physically based shading framework

works fine for me…

 

Lux goes terrain

hi there,

i have just finished the work on the lux terrain shaders (and script).
they allow you to use 4 detail textures + 4 detail bump maps along with a global color and normal map in one shader pass.
the second set of 4 detail and detail normal maps would be drawn in a second pass.

as i assume terrain textures to be none metals and have rather high roughness values specular ambient lighting and reflections are not supported – only diffuse ambient IBL or diffuse ambient spherical harmonics.

lars

 

Great work, also i can definitely see the use of reflective landscape textures, they might not reflect realism all the time but I find giving the artist the obvious would be nice, perhaps thinking walls of obsidian or glass etc

 

hi lazygunn,

i would always ask you to keep in mind that terrains will most likely cover a lot of screenspace.
so a heavy pixelsahder for the terrain will cost you a lot of performance.
for this reason my personal solution is:
make the terrain shader as complex as you really need on common terrain surfaces and make it as slim as possible.
do fancy stuff only on extra added geometry wich will most likely not cover that much screen space.
so if you need some cool reflections here and there simply add some decals. that will probably be much fast to render.

lars

 

hi there,

version 0.045 should be available within he next 10 minutes bringing you the lux terrain shaders.
get the package here:
http://bit.ly/NMzbOs

Changelog version 0.045
- ambient lighting (LuxIBL.cginc)
Due to a bug in unity terrain materials i had to make the "#ifdef DIFFCUBE_ON" a bit more complex.
Now diffuse ambient IBL can be activated per material using the material inspector or globally for shaders in which the keyword "USE_GLOBAL_DIFFIBL_SETTINGS" is enabled.
Sorry for that mess.

- lighting (LuxLightingPhong.cginc)
color output.alpha is reduced to: c.a = s.Alpha;
as long as anybody can tell me what the rest sould be good for i will keep it this simple.

- Lux terrain shaders added

- documentation added

- DontnodGraphicChartForBlinnMicrofacet look up chart added

 

link is already dead 404 not found

 

sorry, it just took ages to upload the package…
but it is online now.

lars

 

This seems like an excellent package, it will really enable all devs to experiment with high-end class graphics features. Which also means that aspiring artists will have a head start into learning to use new tech and thus becoming more attractive to developers/employers. Maybe I'm a bit overly enthusiastic, but I have a weak spot for cool graphics tech stuff.
Thanks a lot for providing this, will experiment with it now.

 

thank you.
and let me know what you think about the framework.

lars

 

larsbertram1, when I import lux package to an empty project I get many shader errors:
'DIFFCUBE_OFF' already defined at line 13
on almost every shader in package.
Standart Demo scene materials doesn't work, but Terrain demo looks good.
Should I change some global settings prior to compilation? I commented out #define DIFFCUBE_OFF in LuxIBL.cginc and recompiled shaders. It almost worked. And what is the 'right' way to fix it?
Thank you very much for your work and support anyway.

 

hmm, it was late yesterday night when i uploaded the package.
usually of course it should just compile fine but i will have a look into it.
and may be replace the latest package.

lars

 

hi dnnkeeper,

i have just recompiled all shaders and do not get any errors at all (unity 4.3.4).
so may be your download is corrupted?

lars

[edit:]
dnnkeeper, you are right: the modified LuxIBL.cginc broke the standard Lux shaders.
sorry about that but i will fix this as soon as possible.

lars

 

hi there,

version 0.046 now is available:
http://bit.ly/1lXJJFZ

it fixes the problems introduced in version 0.045.
thank you dnnkeeper for pointing me towards this.

lars

changelog version 0.046
- ambient lighting (LuxIBL.cginc)
Fixed errors from version 0.045.
Shaders may declare "#define NORMAL_IS_WORLDNORMAL" to skip the calculation of the worldnormal and speed up rendering.
Used e.g. by the terrain grass shaders as here normal equals worldnormal.


- Lux terrain shaders:
Improved normal blending between different shader passes.
Added a the possibility to use a second normal map on detail texture number 3 to hide tiling artifacts on high frequent and bumpy textures such as rock.


- Lux terrain grass and vertex lit shaders added

 

fair points and a good case, i want to watch this and i will, im probably obviously by now using rtp which offers a lot of nice tricks for getting the most ot of your territory with optimising, but i guess i like tools to be there, just so i know they're there... and looking at a pragmatic commercial project side of things, there isnt one for me so I love all the tools added to these things. I'll definitely be watching thing, i dont see any reason wehy it wouldnt grow, its much desired technology being handled very well

 

hi lazygunn,

as far as terrain rendering is concerned there is probably no better solution out there than rtp3.
and i am glad that tom will ship rtp3.1 ready work along with lux.

so the standard lux terrain shaders are for people you can not afford rtp or just do not need all its functionality but look for a small, fast and easy to tweak terrain shader offering physically based shading and IBL.

lars

 

Sounds fair and have already read about 3.1 working alongside lux and its a great prospect. While no rush when 3.1 gets fully released I do hope to see your foliage shaders adjusted to work alongside the system, cause that really is a very attractive prospect

 

Hi Lars, Just curious are lux compatible with marmoset workflow?? something like these
http://www.marmoset.co/toolbag/learn/pbr-practice
http://www.marmoset.co/toolbag/learn/pbr-theory

 

hi rea,

[edited because it was off topic… sorry about that]
yes, lux is more or less compatible with the marmoset workflow.
wording might differ, but it is more or less the same.

albedo = albedo or diffuse texture
microsurface = roughness
reflectivity = specular color

may be the wording of quixel (?) is less disturbing but it just means the same.
and if you have a look at the references a the bottom of the pages you have linked to you will find some links to the blog of sebastien lagarde whose work is the basis of lux.


lars

 

Hi Lars, Great to hear that and fully understood about the cubemap tools so no worries about it . And for your decision about not supplying properties slider i starting to understand why you did that, and i agree about it especially for performance reason. My only request is to add some kind of example shader and documentation for everybody so they can adapt their custom shader to lux, i got some relief and box projected cubemapping that i loved to make it compatible with Lux.
The only thing that a little bit downer right now is that unity can't use HDR cubemap to get a nice reflection.

Edit: Oh and about cavity, well to be honest i still don't what it used for. To occlude the IBL specular??
so i guess you can skip it for know (except if there's somebody else asking for it )

 

hi rea,
i should not have answered your post last night...
but now i will get back on track and answer your questions:

sliders: the latest packages ship with an shader called "Lux Bumped Specular Materialtest" which offers sliders and different ipnut texture slots so you do not have to create combined textures (specular color and roughness).

example shader: i would call the "Lux Bumped Specular" shader an example shader.

documentation: the "_Lux Documentation".txt file already contains a section "WRITING LUX SHADERS" but you will have to open the file as the unity inspector will just cut off most of the document and simply writes: "<… etc …>". may be i should add a table of content.


projected cubemapping
if you can make it work with lux it would be great if you shared it... what would take safe me some work.

HDR cubemap
lux already supports HDR cubemaps for diffuse and specualr ambient lighting.

Cavity
Lux supports an ambient occlusion map that will occlude diffuse and specular ambient lighting (image based or using sh).
but it does not make a difference between diffuse and specular – just one mask (alpha) for both. i might change this and offer 2 channels to control occlusion for diffuse and specular separately.

lars

 

hi rea,

i have just edited my answer form last night…
lars

 

just as reference, could have something interesting:
"Playing with the microfacet model and parameters proposed by Disney at Siggraph 2012. Roughness increases in the x axis and metallicity increases on the y axis."
https://www.shadertoy.com/view/4dBGRK

 

very nice, but is the disney brdf (cook torrence) not a bit too expensive?
lux uses normalized blinn phong which should be a lot cheaper.

lars

 

lol no worries about it

How about GGX spec??

 

what do you mean by this? Trowbridge-Reitz?
that will be pretty expensive too i guess.
and pretty much anybody uses blinn phong…

 

hi there,

version 0.05 is available!
get the latest package here: http://bit.ly/1cWzImc

i think this version will fix some issues with dx11 / dx9 when the ambient specular Cubemap was disabled.
at least it looks fine on my virtual windows machine.
next to that: tree creator shaders! so now we have pretty much everything you need if you want to use Lux with your terrains.

lars


changelog version 0.05


!!! important !!!
- example shaders
writing to o.DeferredFresnel changed to:
o.DeferredFresnel = exp2(-OneOnLN2_x6 * max(0, dot(o.Normal, normalize(IN.viewDir) )));
as it could cause some lighting artifacts on dx9 / dx11. now it is even a bit faster ;-)
You should do so in all your individual shaders too.
- ambient lighting (LuxIBL.cginc)
spec ambient IBL changed from spec_albeo.rgb and spec_albedo.a to o.SpecularColor and o.Specular – just to make it more flexible
- LuxLightingPhong.cginc
optimized "Final Composition" (forward lighting)
- tree creator shaders added

 

@larsbertram1: This is, i say, one of the most impressive shader packs i have ever seen! I do have one question though: how come the download link isn't in the main post?

EDIT: The stupid download didn't complete properly - it keeps stopping. Could you post a more reliable link please? (like a Google Drive link. that's what i use, and it's fast!)

 

Hey there again

This was so pretty that i decided to show here
The weapon is using Lux shaders. Physical based shaders really bring out the detail in textures.

For comparison purposes, i made 4 images using Lux, default shaders, with and without image effects.

Lux with image effects:


Default bumped specular with image effects:


Lux without image effects:


Default bumped specular shader without image effects:



Could you implement a lux shader that blends 2 textures given a 3rd texture? (ex: white shows texture and normal map 1, black shows texture and normal map 2). This would be great for very large structures and break the tilling.

 

Thanks, i'll try that.
I haven't tried the terrain and tree shaders because i got 100+ errors when importing them, and when i played the game, the grass was weird, so i deleted the terrain shaders folder.
I'll import it again and show you the errors.

 

Here are some screenshots with the errors:




I do have some problems with my project. I submitted a bug report to Unity but they still haven't been able to fix it.
My project crashes when switching between dx9 to dx11, and RTP v3 doesn't compile new shaders.

Maybe this problem with lux shaders is also linked to the problem i've been having for a very long time...

EDIT:

Regarding the shader i suggested in the previous post, here's an image of the shader that i made with strumpy shader editor that blends 2 textures and normal maps given a another texture.

 

I translated Disney's BRDF to Unity and honestly, the performance hit is not that bad. We're using it in our game with vastly populated scenes and it works great. I'd be glad to include it in Lux if you guys are interested and if lars allows it of course .

 

hi jesta,

that would be great.
right now i am working on version 0.06 which will allow you to choose between blinn phong and cook torrence.
may be we can include disney’s brdf as 3rd option – or replace one of the other two.
a comparison between those would be great.

lars

 

hi there,

as i am still working on version 0.06 i just want to give you a little preview on the the upcoming lighting solutions.
lux will support cook torrence and blinn phong based lighting.

and if i compare both lighting functions to the dontnod reference chart only having a look at the direct specular highlight blinn phong is the clear winner:






But when taking ambient specular reflections into account the result suddenly changes.
Now the direct specular highlights Cook Torrence produces fit much better with the specular highlights i get from the ambient specular cube.




so what?
i guess it absolutely depends on what kind of look you want to achieve.
Blinn Phong is rather cheap and will give you very nice and distinguished specular reflections whereas cook torrence will produce a very nice tail around the highlight giving you the possibility to create much more variety especially on rough surfaces – at some higher costs i have to admit.

lars

 

This thread has been fascinating so far and i've been so waylaid by random things i've not had a chance to actually give lux a proper look-in. Its been quite a while since I did some decent quality art for these things so, having discovered ddo, it seems like a good time to soon create things that can really showcase all these developments. It's something there's a severe lack of at the moment, a lot of technology and very bright application but not enough pretty things!

Oh well i'm going to be getting very comfortable with rtp soon and the existing communication between rtp and lux is promising, and hopefully i'll get the momentum to make some nice things. Very impressed with the work so far, i've got a big interest in the more outlandish lighting and surface types, to the point of creating concepts by which they'd feature strongly, so i'm looking forwards to seeing all the directions it goes! These seem very good models for reproducing forms you might consider engineered, when a good breakdown of the disney brdf gave a nice look into how it reproduces the not-so-perfect, when mixed with translucent materials, cloth etc, exciting tools to actually get to use. I'm still honestly finding a paucity of mainstream games adopting these approaches.. wether its for performance reasons or otherwise it seems nice to have a situation i which much smaller groups start taking the, what im finding conservative, shooting foreign people game making studios by surprise

Great work anyways

 

@lazygunn: very lengthy explanation, but either way, I agree - the terrain example looked awesome! well, except the grass... it looked burnt and dead for some reason. I am also looking to port my unity free water shader to this for more realism, it is this good. definitely worth the glitchy download I experienced!

@larsbertram1: Just a question: Can you help with porting this water shader? (It's one i built for my unity free terrain challenge thread)
Thread containing water shader
I gave porting my shader a shot, but it's already too complex... And BTW, what is Disney BRDF? anything will do: website, link, screenshot. anything.

 

hi there,

version 0.06 is available and brings:
- cook torrance based directional lighting
- vertex blend shaders (as requested by eskovas)

download it here (this time google drive instead of dropbox):
http://bit.ly/NqwWzy


lars




changelog version 0.06


this version is a major update because it introduces a Cook Torrance based approach as second lighting model next to Blinn Phong.
In order to make it possible to switch between these models I had to rewrite some parts of the framework. i took this chance to make the naming a bit more flexible and descriptive:


"LuxLightingPhong.cginc" changed to "LuxLightingDirect.cginc"
"LuxIBL.cginc" changed to "LuxLightingAmbient.cginc"


- surface shaders
the name of the Lux lighting function changed to "LuxDirect":
#pragma surface surf LuxDirect noambient


the name of the direct lighting functions include changed:
#include "LuxCore/LuxLightingDirect.cginc"


a new pragma makes it possible to swith between the lighting models:
#pragma multi_compile LUX_LIGHTING_BP LUX_LIGHTING_CT


writing to o.Specular has changed to a function call:
o.Specular = LuxAdjustSpecular(spec_albedo.a);


- minor changes and fixes:
-- VertexBlend shaders added
-- Lux ambient lighting: if "diffuse cube IBL" is disabled the shader won’t add ambient lighting based spherical harmonics in case the object is lightmapped.
-- tree creator redertex shaders fixed but this will be an ongoing process...
-- terrain shader first pass: fixed for cook torrence using complex blending for detail normal

 

grass only uses diffuse lighting – the Lux grass shader just adds image based ambient diffuse lighting if this option is enabled for the terrain.
so the look of the grass mainly depends on your textures. and i have just taken one from the standard assets.

@larsbertram1: Just a question: Can you help with porting this water shader? (It's one i built for my unity free terrain challenge thread)
Thread containing water shader
I gave porting my shader a shot, but it's already too complex... And BTW, what is Disney BRDF? anything will do: website, link, screenshot. anything.[/QUOTE]

i will have a look at it but i would guess that you do not have to do anything to the shader – as it only works in forward.
it will just work but not benefit from Lux’s direct and ambient lighting functions.

lars

 

@Larsbertram1: Thanks for taking my google drive use suggestion! And yes, thanks for explaining the grass thing - it simply looked bland next to the epic lighting! And last of all, great work! And again, what is Disney BRDF? i am still confused about it.

 

hi fuzzy,

i am no water expert so do not expect too much,. but here we go:

in order to make your shader work with lux you have to safe a lot of texture interpolators first (for lux we have to add float3 worldNormal; float3 worldRefl;and INTERNAL_DATA so the shader will not compile if we also add several texture coords).
i have done so by just passing in one uv_coord and calculating all other in the fragment shader.

next you have to take care of the special Lux outputs params especially o.SpecularColor and o.Specular.
no _power or o.Gloss needed.

further changes:
offset is calculated taking the combined normal y-component into account.
fresnel controls strength from refraction vs reflection.
reflections come from the specular ambient cube.
(please note: the shader uses: #define DIFFCUBE_OFF to skip diffuse ambient lighting. all other #defines / multi_compile directives should be adjusted personally. have a look at the lux documentation.)

refraction and reflection are written to o.Emission.

if added a PRO shader which uses grabpass so you do not have to render the scene twice.
i have tweak the js.


lars

get the package here:
https://drive.google.com/file/d/0B7wuYyJnwF9dVUMzclUxeHEwVDQ/edit?usp=sharing

 

a pretty advanced BRDF which more or less means: direct lighting function.

lars

 

@larsbertram1: note i have unity free, so GrabPass wouldn't work here. Anyway, thanks for giving a shot at porting my shader! And i still don't know what Disnet BRDF is. maybe i should google it...

EDIT: My shader keeps saying "include callback failed" Any suggestions?

 

it works for indie and pro.
falback: you have to place the folder on the same level as the original lux folder.
have a look at the shader to see at which path it looks for the include and make sure that it will point to the right luxcore folder.

lars

 

@larsbertram1: still doing it, even when in root assets folder. how would you set up the path? because mine says "../../Lux/Lux Shader/LuxCore/<includefile>" and it still throws the error. and i finally saw your post on BRDF, thanks!

EDIT: i think it's because i am still using 0.05... OOPS!

 

I was looking at compute shader convolution today, and fancied giving it ago with this project in mind, i just had no idea factors i needed to keep in mind. Format encoding? Kernel size? I'm no expert but i thought I might look into it

 

@Larsbertram1: got it working, but the refraction's upside down! What has gone wrong with my precious shader?! Other than that, it looks awesome!

 

Ok, I have a working shader, just had to flip the Y coordinate in your hpos variable, as that was why it was upside down. Thank you for your help! And do you want me to include this shader in a future release of Lux? cause a lot of people would die for a great water shader on Lux!

 

Sweet...i'll test the latest version...
@Lars btw what do you mean with shader convolution?? or is it convolution shader??

Another question, if i want to change lighting model do i need to recompile the shader??

 

hi fuzzy,

flipping the y coordinate is not necessary on mac – it just worked the way i shipped the package.
so it might be a good idea to detect the platform by script and flip the rendered texture (also by script).
as fsar as including the shader is concerned: lux does not require any own water shader as those always work in forward. so any water shader just will render fine. you might benefit a bit from advanced direct lighting and you will benefit from ambient cubemap reflections unless you use realtime reflections like most people using pro will prefer i guess.

so i will keep the basic lux distribution around the size it has now (as it already takes about 25 min to import an my 2009 mac book pro). or come up with my own water solution.

but i would like to encourage to to publish your own package – may be supporting both: the classic unity lighting and lux.

lars

 

hi rea,
did i write anything about convolution shader? i can’t remember…

changing the lighting model is just a simple click (setup lux script).
that’s the reason why it takes so long to import the package…
i think it is good at least as long as lux is still in beta. but it might change in the future.
i am still not sure how to deliver a "final" package:
- all features enabled by default or not – which would force people to edit the shader code manually (rewriting #defines).
- all shaders present at first import – or several packages to import so you just get what you need.

lars