What am I doing wrong with Shader.SetGlobal...

As a minimal example, I'm trying to set a global property that all shaders should be able to access.

C#

Code (CSharp):

1. using UnityEngine;
2.  
3. public class SetGlobalColorProperty : MonoBehaviour {
4.  
5.     private void OnPreCull()
6.     {
7.  
8.         Shader.SetGlobalColor("_GlobalColor", Color.blue);
9.        
10.     }
11.  
12. }

Shader

Code (CSharp):

1. Shader "Unlit/GlobalColor"
2. {
3.     SubShader
4.     {
5.         Tags { "RenderType"="Opaque" }
6.         LOD 100
7.  
8.         Pass
9.         {
10.             CGPROGRAM
11.             #pragma vertex vert
12.             #pragma fragment frag
13.            
14.             #include "UnityCG.cginc"
15.  
16.             struct appdata
17.             {
18.                 float4 vertex : POSITION;
19.             };
20.  
21.             struct v2f
22.             {
23.                 float4 vertex : SV_POSITION;
24.             };
25.  
26.             uniform float4 _GlobalColor;
27.  
28.             v2f vert (appdata v)
29.             {
30.                 v2f o;
31.                 o.vertex = UnityObjectToClipPos(v.vertex);
32.                 return o;
33.             }
34.            
35.             fixed4 frag (v2f i) : SV_Target
36.             {
37.                 return fixed4(_GlobalColor);
38.             }
39.             ENDCG
40.         }
41.     }
42. }
43.  

I've tried SetGlobal Vector and Color both, tried adding 'disable batching' in the tags of the shader. Is the Shader.SetGlobal... being called in the wrong execution order?

https://docs.unity3d.com/ScriptReference/Shader.SetGlobalVector.html

 

I honestly can't see any errors in your code.

Some things you might want to try to debug is.

Call it in Update and debug.log the value.
Try to create a variable myColor = new Color(0, 0, 1); and use that inside of Color.blue.

 

Calling it in Update worked like a charm.

 

OnPreCull only gets called if the script is placed on the same game object as a enabler camera component. Likely why it wasn't working for you before.

 

Seem to be exactly the case. "This function is called only if the script is attached to the camera and is enabled." from the docs

Only checked this page and assumed it would get called anyway.

Always nice to know the reason things didn't go as one thought.

 

for others out there.... the SetGlobal values can also get overwritten by other screen space or filter FX. IF you have such components on the Camera, try disabling them.