Can I ignore light cookie per object?

Hi, I'm making a animated cloud shadow effect by applying an animated render texture to the main directional light as a cookie. However, I have cloud meshes in the scene and they are also effected. Is there a way to make a shader ignore cookies? One solution that I would like to avoid is creating a new directional light without a cookie for these objects. I'm using the build in standard render pipeline.

Thanks for any help!

 

Yes. But you’ll need to write a custom shader to do so. They key is the keyword

DIRECTIONAL_COOKIE

. That gets enabled on a shader when the directional light is using a cookie. To avoid the cookie being used, you need to either disable that keyword prior to

#include AutoLight.cginc

showing up in the shader. For a fully custom shader you can add

#undef DIRECTIONAL_COOKIE

before including the AutoLight.cginc, but you can’t do that for a Surface Shader, which is a lot easier to slap together quickly and match the built in shaders. So instead you can do this:

Code (CSharp):

1. #if defined(LIGHT_ATTENUATION)
2. #undef LIGHT_ATTENUATION
3. #define LIGHT_ATTENUATION(a) SHADOW_ATTENUATION(a)
4. #endif

If you add that near the start of the default Surface Shader that’s created when creating a new shader in the project view, it should be unaffected by the light cookie on a directional light.

 

Thanks for the reply! What you're saying makes sense but it didn't seem to work. I made a new standard shader to test. Does this look right?

Code (CSharp):

1. Shader "Custom/testStandardShader"
2. {
3.     Properties
4.     {
5.         _Color ("Color", Color) = (1,1,1,1)
6.         _MainTex ("Albedo (RGB)", 2D) = "white" {}
7.         _Glossiness ("Smoothness", Range(0,1)) = 0.5
8.         _Metallic ("Metallic", Range(0,1)) = 0.0
9.     }
10.     SubShader
11.     {
12.         Tags { "RenderType"="Opaque" }
13.         LOD 200
14.  
15.         CGPROGRAM
16.         #if defined(LIGHT_ATTENUATION)
17.         #undef LIGHT_ATTENUATION
18.         #define LIGHT_ATTENUATION(a) SHADOW_ATTENUATION(a)
19.         #endif
20.  
21.         // Physically based Standard lighting model, and enable shadows on all light types
22.         #pragma surface surf Standard fullforwardshadows
23.  
24.         // Use shader model 3.0 target, to get nicer looking lighting
25.         #pragma target 3.0
26.  
27.         sampler2D _MainTex;
28.  
29.         struct Input
30.         {
31.             float2 uv_MainTex;
32.         };
33.  
34.         half _Glossiness;
35.         half _Metallic;
36.         fixed4 _Color;
37.  
38.         // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
39.         // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
40.         // #pragma instancing_options assumeuniformscaling
41.         UNITY_INSTANCING_BUFFER_START(Props)
42.             // put more per-instance properties here
43.         UNITY_INSTANCING_BUFFER_END(Props)
44.  
45.         void surf (Input IN, inout SurfaceOutputStandard o)
46.         {
47.             // Albedo comes from a texture tinted by color
48.             fixed4 c = tex2D (_MainTex, IN.uv_MainTex) * _Color;
49.             o.Albedo = c.rgb;
50.             // Metallic and smoothness come from slider variables
51.             o.Metallic = _Metallic;
52.             o.Smoothness = _Glossiness;
53.             o.Alpha = c.a;
54.         }
55.         ENDCG
56.     }
57.     FallBack "Diffuse"
58. }
59.  

 

Whoops! Replacing the wrong macro.

Code (csharp):

1. #if defined(DIRECTIONAL_COOKIE) && defined(UNITY_LIGHT_ATTENUATION)
2. #undef UNITY_LIGHT_ATTENUATION
3. #define UNITY_LIGHT_ATTENUATION(destName, input, worldPos) fixed destName = UNITY_SHADOW_ATTENUATION(input, worldPos);
4. #endif

 

Perfect, works like a charm! Thanks for the help!