White flash fullscreen shader doesn't work on mobiles.

Unity Engine
1

I have a fullscreen shader that makes the camera it’s applied to flash white. It works fine in the editor, but not on mobile devices.

Here is the coder to the shader itself:

 Shader "Hidden/WhiteFlash"
{
     Properties{
         _MainTex("Base (RGB)", 2D) = "white" {}
     _flash("Flash intensity", Range(0, 1)) = 0
     }
         SubShader{
         Pass{
         CGPROGRAM
#pragma vertex vert_img
#pragma fragment frag
#include "UnityCG.cginc"
             uniform sampler2D _MainTex;
         uniform float _flash;
         float4 frag(v2f_img i) : COLOR{
             float4 c = tex2D(_MainTex, i.uv);
             //float lum = c.r*.3 + c.g*.59 + c.b*.11;
             float3 fl = float3(1, 1, 1);
             float4 result = c;
             result.rgb = lerp(c.rgb, fl, _flash);
             return result;
         }
             ENDCG
         }
     }
}

And here is the script that controls its values:

 public class WhiteFlash : MonoBehaviour
{
     public float intensity;
     private Material material;
     // Creates a private material used to the effect
     void Awake()
     {
         material = new Material(Shader.Find("Hidden/WhiteFlash"));
     }
     // Postprocess the image
     void OnRenderImage(RenderTexture source, RenderTexture destination)
     {
         if (intensity == 0)
         {
             Graphics.Blit(source, destination);
             return;
         }
         material.SetFloat("_flash", intensity);
         Graphics.Blit(source, destination, material);
     }
}

Shaders are a dark art to my poor muggle mind, and the answer to my question is likely something extremely simple that I’m just missing. The code itself is about 98% recycled from a tutorial.

The code works fine in the Unity editor, both in normal and emulated graphics mode. However, once I build and test it on an Android device (tested on an HTC One M9 and a Google Nexus 6P), there just is no flash. Can someone point me in the right direction with this? My Google-fu was of no help.

2

Your shader is likely stripped from the build. Shaders that are only used from code, that aren’t used in any material in project will be stripped. Try to add it to always included shader list (Edit->Project Settings->Graphics->Always Included Shaders)