Shadow and distance attenuation do not work in URP Unlit Graph

Hi!
I'm using Unity 2019.3.0f3 and URP 7.1.7
I'm trying to follow this tutorial:
https://blogs.unity3d.com/pt/2019/0...n-shader-graph-expanding-your-graphs-in-2019/

But the "mainLight.shadowAttenuation" and "mainLight.distanceAttenuation" always return white if using a "Unlit Shader" as Base. It works with a "PBR" shader but this is not what i need (since i need a fully controllable light model.

Is it a bug or there's something new that is not documented about it?

 

So your tutorial is just wrong and there's no way to use custom light model anyway?
I've added this to the mainlight.hlsl (the custom function file) but it's not working too. Any other solution?

 

I don't know yours but somehow my unlit shaders cast shadows in 2019.3.0f3 URP 7.1.6

 

Did you tested with 7.1.7?

 

no there is no package update in package manager.

 

Hi. This is my shader graph and the mainlight.hlsl file. It's yet not working and i'm getting this error:

Shader error in 'Shader Graphs/Base': invalid subscript 'shadowCoord' at /Vitor/Trabalho/Cogumelo/Projetos/Game2020/Game2020/Library/PackageCache/com.unity.render-pipelines.universal@7.1.7/Editor/ShaderGraph/Includes/Varyings.hlsl(118) (on d3d11)

What i'm doing wrong?

 

use the lit graph instead and bypass the built in lighting function by muting its output.
then plug in your custom lighting into emissive:
https://medium.com/@larsbertram1/lwrp-and-custom-lighting-in-shader-graph-6a7c48008a1d

 

That is exactly what I'm doing and what I want to avoid. This is terrible hackish. No way this must be the designed way to do it in a "professional" engine.

 

That solution still only half works, as even when you set all the PRB parameters to 0 (URP 2019.3.0f3) you still don't remove all of what PBR seems to do. So that trick which worked in LWRP doesn't work in URP.

 

i justed had a quick look into the complied shader code: only one light loop survives the shader compiler which is the custom one. tested with urp 7.1.7.

 

Is that in specular or metallic mode? In metallic mode I can clearly see that the metallic lighting is surviving, but not in specular mode, can't say anything about the compilers.

Also, this

presentation references the article at the top of this thread, but it's more recent and shadows are quite clearly working on an unlit node so that might be worth looking into.

 

you have to use specular mode.
metallic does not really exist. it is just an intermediate step which converts metallic to specular. and this step will never set spec to 0,0,0 rather than to a fixed spec value. so in this case some lighting code actually survives...

 

@phil_lira please dont leave us in the dark here.

I watched the video above to learn how to do custom lighting.

The resources for the video above are found here:
https://github.com/Unity-Technologies/ShaderGraph-Custom-Lighting

These steps do not work anymore. As @CogumeloSoft pointed out, you get an error. It seems you need to declare another keyword to make it work - REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR. If you do not define this keyword, then the Varyings struct does not contain shadowcoord interpolator. But there is no way to define keywords in the shadergraph?

The shader graph lets you add a 'predefined' keyword.. For example, I enter this:


But it still doesn't seem to work.

How do we just get main light information, including shadows?

I still get the same error as him:

 

I was able to get main light information + shadows using this code.

https://pastebin.com/buzfq0eJ

Works for me in 7.2.0 URP

 

you can wipe out all:
#if SHADOWS_SCREEN
7.2. does not support screen space shadows any more.

 

Cool thank you for the tip!

 

That gives you shadows, but they're low Rez and seem to disagree with the shadow Cascades

 

This worked for me, including part underneath about removing shadow screen etc

 

I was able to use that pastebin to get shadow attenuation working, but like xHammy the cascade info seems to be working incorrectly - my shadows are a lot blockier than they should be. Any solutions?

 

1. Unlit means not lighten. So the word suggests it receives no lighting (no light nor shadow).

2. PBR is a Physically Based Rendering model. A completely custom lighting model should not be used in another lightning model (PBR).

3. There is no custom lightning master node in shader graph.


I personally think there should be some custom lighting master node that is similar to the unlit graph.

If there is no custom lightening maser node, I think an unlit shader should be used then you trying to implement a custom lighting model. (because it is the simplest master node). And in order to make a custom lighting model, an unlit shader graph should be able to receive at least a light and shadow data.

If there is no normal way to implement the simplest custom lighting, a scripted build pipeline is not enough customizable at least. And not good enough in general. For me.


Taking into account the above sentences,
Answer please, how do you think one can do performant and precise simple custom lighting model in shader graph without getting a base lighting element as shadow data in unlit master node and without custom lightning master node(and without dancing with PBR graph which is already different lighting model)?

 

If you are using hard shadows without cascades, you can reduce your URP setting shadow distance.

If you are using cascades and hard shadows, you may need to monkey around more with keywords and settings, not sure.

However, if you are using soft shadows, this helps:

 

And if you define shadow cascade keyword now it will receive cascades ( just be shure those are keywords and not the properties).

Thank you it is working in URP 7.3.1

 

Thanks so much for your help all!

Defining both of those keywords - _SHADOWS_SOFT (as multicompile global default) and _MAIN_LIGHT_SHADOWS_CASCADE (as shader feature global default), combined with this custom lighting function worked for me.

Code (CSharp):

1. void MainLight_half(float3 WorldPos, out half3 Direction, out half3 Color, out half DistanceAtten, out half ShadowAtten)
2. {
3.     #if SHADERGRAPH_PREVIEW
4.         Direction = half3(0.5, 0.5, 0);
5.         Color = 1;
6.         DistanceAtten = 1;
7.         ShadowAtten = 1;
8.     #else
9.         #if SHADOWS_SCREEN
10.             half4 clipPos = TransformWorldToHClip(WorldPos);
11.             half4 shadowCoord = ComputeScreenPos(clipPos);
12.         #else
13.             half4 shadowCoord = TransformWorldToShadowCoord(WorldPos);
14.         #endif
15.             Light mainLight = GetMainLight(shadowCoord);
16.             Direction = mainLight.direction;
17.             Color = mainLight.color;
18.             DistanceAtten = mainLight.distanceAttenuation;
19.  
20.         #if !defined(_MAIN_LIGHT_SHADOWS) || defined(_RECEIVE_SHADOWS_OFF)
21.             ShadowAtten = 1.0h;
22.         #endif
23.  
24.         #if SHADOWS_SCREEN
25.             ShadowAtten = SampleScreenSpaceShadowmap(shadowCoord);
26.         #else
27.             ShadowSamplingData shadowSamplingData = GetMainLightShadowSamplingData();
28.             half shadowStrength = GetMainLightShadowStrength();
29.             ShadowAtten = SampleShadowmap(shadowCoord, TEXTURE2D_ARGS(_MainLightShadowmapTexture,
30.             sampler_MainLightShadowmapTexture),
31.             shadowSamplingData, shadowStrength, false);
32.         #endif
33.     #endif
34. }

 

Hi guys! I followed all this steps, but i got this error. Any ideas? Unity 2019.3.5f1 URP 7.3.1

 

Change precision to half.

 

Nothing happens

 

I changed precision to half and added an additional Vector3 input. Now custom function looks similar to the one shown here. But the material now has only its own shadows. But I need to make this unlit material capable of getting drop shadows.

 

If we are talking about self shadows - I made it with _WorldSpaceLightPos0 parameter reference. Simple and works great. But i need drop shadows...

 

You need to multiply shadow attenuation(from custom function) with other nodes, for example with your remap node. Shadow attenuation contains data about external shadows (ranging from 0 - 1). There 0 means full shadow and 1 means no shadow (or vice verse, do not remember).
Look at my post with the screenshot above.

 

Here is my scene now. And there's no drop shadows. And also when directional light is strait top down everything becomes black. Sorry I don't have much experience in programming, what am I missing?

 

You are missing object that casts shadows. Make some big object and put it before objects you want to get shadows on (move big object around and change direction of directional right until you get the shadows on small objects). The position of direction light does not matter. Only rotation describes the direction of the light.
Or make some plane and put it beneath small objects. Make shure the plain also has same material applied. And shadows should appear on that plain.

 

The fact is that both spheres are aligned, so the far sphere should get a shadow from the first sphere. Besides, the gray rectangle in the background is a large square positioned right after the spheres and has the same material.

 

If your direction light shadows are enabled and shadows are enabled in general (do default materials receive shadows?). And if your used thiscode.

Code (CSharp):

1. void MainLight_half(float3 WorldPos, out half3 Direction, out half3 Color, out half DistanceAtten, out half ShadowAtten)
2. {
3.     #if SHADERGRAPH_PREVIEW
4.         Direction = half3(0.5, 0.5, 0);
5.         Color = 1;
6.         DistanceAtten = 1;
7.         ShadowAtten = 1;
8.     #else
9.         #if SHADOWS_SCREEN
10.             half4 clipPos = TransformWorldToHClip(WorldPos);
11.             half4 shadowCoord = ComputeScreenPos(clipPos);
12.         #else
13.             half4 shadowCoord = TransformWorldToShadowCoord(WorldPos);
14.         #endif
15.             Light mainLight = GetMainLight(shadowCoord);
16.             Direction = mainLight.direction;
17.             Color = mainLight.color;
18.             DistanceAtten = mainLight.distanceAttenuation;
19.         #if !defined(_MAIN_LIGHT_SHADOWS) || defined(_RECEIVE_SHADOWS_OFF)
20.             ShadowAtten = 1.0h;
21.         #endif
22.         #if SHADOWS_SCREEN
23.             ShadowAtten = SampleScreenSpaceShadowmap(shadowCoord);
24.         #else
25.             ShadowSamplingData shadowSamplingData = GetMainLightShadowSamplingData();
26.             half shadowStrength = GetMainLightShadowStrength();
27.             ShadowAtten = SampleShadowmap(shadowCoord, TEXTURE2D_ARGS(_MainLightShadowmapTexture,
28.             sampler_MainLightShadowmapTexture),
29.             shadowSamplingData, shadowStrength, false);
30.         #endif
31.     #endif
32. }

than I do not know why there is no shadows.

ALso as I remember parameter names should be exactly named in code and in custom function node.

 

If I rename the function everything becomes pink. Function working only with MainLight name. As you can see on the screenshot shadows are enabled. Objects cast shadows on URP lit mtl, but not on each other. Also I get an error invalid subscript 'shadow Coord', when the _MAIN_LIGHT_SHADOWS keyword added.

 

Your custom function node has one input parameter. That parameter must be Vector3 and named "WordPos".
You vurrently have it as Vector1 and named New.

 

Uff...How could i miss that..Of course position should be vector3. Thanks a lot! It finally works! I'm sorry to bother you, but can there be a way to control the color of the shadows? =)

 

Yes.
Basically you need the shadow attenuation and possibly self shadows as a mask.
Then you use this mask to control which color will it be. For example you can just use a lerp node. You put that mask in the alpha of the lerp node and 2 other nodes will be shadowed and lighted colors. (just put wire that you connected to Unlit color node into new lerp alpha node). (also after you make dot product of light and normal you need to add saturate node becouse dot product is in rang of -1 to 1 and you most likely need it to be in range of 0 to 1.

That way color of shadow is controlod by material of object itself. But,
You can also mix your desired shadow color with environmental color in order for environment to affect shadow color.

 

Awesome! Thank you! I'll download your app and click on ads =)

 

)))) Enjoy ))))

 

@TextusGames Hi I'm using Unity 2019.1.f1 and HDRP. I try to follow your advice but I can't. I have one last error who I don't arrive debug "TransformWorldToShadowCoord". If you can help me, you will save me.

 

Most likely in HDRP or in unity prior to 2019.3 you need the different code to access shadow data ("TransformWorldToShadowCoordinate" this function is not exists in HDRP engine code it seems..)
My advice is to google for a code that can return shadow data in HDRP specifically and create a custom node with that code.

 

Hey,

I've implemented these same steps and it works perfectly in the editor, but I've noticed that once I actually build it the shader does not receive/use the shadowcascade information. Below I've added some images of the shader, and the scene in playmode and a build version. This is in Unity 2019.4.0f1. Has anyone had the same problems? And did you manage to fix it?
EDIT: I made a separate post with a clearer description of my problem: https://forum.unity.com/threads/lig...r-playmode-but-not-in-a-build-version.915560/

Shader (the custom function is the one linked in this thread)
Playmode (It works as intended, the custom material at the bottom receives shadows and their resolution differs with distance from the camera. The last one does not receive a shadow because it is beyond the shadow distance)

The Build version (the custom material no longer receives shadow information ???, notice that the standard URP Lit shader does receive shadow information on the plane)

Build version with shadow cascades turned off (Now it does receive shadows but they are not cascaded, nor are they soft, while soft shadows is enabled)

 

The Distance Attenuation in a stand-alone build does not appear to work (yet works fine in the editor).

Anybody else seeing this issue?

Tested in:
Unity 2019.4.2f1
URP - 7.4.1

 

I have same problem. And decide to use Two or Four Cascades mandatory.
Because I don't use No Cascades.

So i can change my custom function code from
half4 shadowCoord = TransformWorldToShadowCoord(WorldPos);
to
half cascadeIndex = ComputeCascadeIndex(WorldPos);
half4 shadowCoord = mul(_MainLightWorldToShadow[cascadeIndex], float4(WorldPos, 1.0));

It didn't need to check _MAIN_LIGHT_SHADOWS_CASCADES keywords
So it can run in build version.

 

This also works for me

 

This allowed for me to access the other cascades

 

I have the same issue, and this works for me.

 

In 2019.4.8f Once again shadow data is not working correctly with cascades. It is greatly reduces shadow disance and produces artifacts. Is there a new way to get shadows?