Alpha mask shader working in Unity editor but not when deployed to iOS

Graphics Shaders & Materials
1

I have the following shader:

Shader"Crop/TransparentWithAlphaMask"
{
Properties {
_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
_AlphaTex ("Alpha (RGB) Trans (A)", 2D) = "white" {}
}

SubShader {
Tags {"Queue"="Transparent"}
LOD200

CGPROGRAM
#pragma surface surf Lambert alpha

sampler2D _MainTex;
sampler2D _AlphaTex;

structInput {
float2 uv_MainTex : TEXCOORD0;
float2 uv2_AlphaTex : TEXCOORD1;
};

void surf (Input IN, inout SurfaceOutput o) {
fixed4 c = tex2D(_MainTex, IN.uv_MainTex);
fixed4 alpha = tex2D(_AlphaTex, IN.uv2_AlphaTex);
o.Albedo = c.rgb * alpha.a;
o.Alpha = alpha.a;
}
ENDCG
}

Fallback "Diffuse"
}

It is supposed to mask the texture _MainTex with the alpha channel of texture _AlphaTex. They both require different UV sets (UV1 for _MainTex and UV2 for _AlphaTex)

This shader works perfectly in the editor but not when deployed to an iOS device. Does anyone know what is causing this issue? What renders in a black version of the alpha mask and nothing else (because of this I know it is using the correct UV’s for the mask texture).

The mesh I’m using for this is a dynamically built mesh generated at runtime, with shadows casting/receiving/light probes disabled.

Any help would be greatly appreciated.

2

I found what my issue was. Going to post it here incase someone has a similar issue in the future. The reason everything was coming out black on iOS was I wasn’t supplying normals for my mesh. Seems the desktop/standalone shaders show different results when no vertex normals are supplied. This is what was causing me to think my shader wasn’t compatible with iOS.

3

Hey, So what exactly did you do to fix it?

4

I wasn’t setting normals for my mesh so I set them with mesh.normals = normals (where normals is an array of Vector3’s one per vertex). If you’re seeing black geometry on iOs and not in the editor this could be the issue.