trouble with 2nd UV

I am trying to add a second UV to my surface shader.

using texcoord1 compiles but the texture is mapped as a solid color

using TEXCOORD1 doesn’t compile.

Can someone help me out here?

Shader "Custom/CaribbeanBlue" 
{
Properties 
{

    _Color ("Main Color", Color) = (1,1,1,1)
    _SpecColor ("Specular Color", Color) = (0.5,0.5,0.5,1)
    _Shininess ("Shininess", Range (0.01, 1)) = 0.078125
    _ReflectColor ("Reflection Color", Color) = (1,1,1,0.5)
    _MainTex ("Base (RGB) RefStrGloss (A)", 2D) = "white" {}
    _Illum ("Illumin (RGB)", 2D) = "black" {}
    _Cube ("Reflection Cubemap", Cube) = "" { TexGen CubeReflect }
    _BumpMap ("Normalmap", 2D) = "bump" {}

}

SubShader 
{

    Tags { "RenderType"="Opaque" }

    LOD 400

CGPROGRAM

#pragma surface surf BlinnPhong vertex:vert

#pragma target 3.0

 

sampler2D _MainTex;
sampler2D _BumpMap;
sampler2D _Illum;
samplerCUBE _Cube;

float4 _Color;
float4 _ReflectColor;
float _Shininess;

 

struct Input 
{

    float2 uv_MainTex;
    float2 uv_BumpMap;
    float2 uv2;
    float3 worldRefl;
    INTERNAL_DATA

};

void vert (inout appdata_full v, out Input o)
{
      
     o.uv2 = v.TEXCOORD1.xy;
      
}

 

void surf (Input IN, inout SurfaceOutput o) {

    fixed4 tex = tex2D(_MainTex, IN.uv2);

    fixed4 illum = tex2D(_Illum, IN.uv_MainTex);

    fixed4 c = tex * _Color* illum;

    o.Albedo = c.rgb;

    

    o.Gloss = tex.a;

    o.Specular = _Shininess;

    

    o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));

    

    float3 worldRefl = WorldReflectionVector (IN, o.Normal);

    half4 reflcol = texCUBE (_Cube, worldRefl);

    reflcol *= tex.a;

    o.Emission = reflcol.rgb * _ReflectColor.rgb;

    o.Alpha = reflcol.a * _ReflectColor.a;

}

ENDCG

}

 

FallBack "Reflective/Bumped Diffuse"

}

Try uv2_MainTex. This will be populated with the secondary UV coordinates in the mesh, transformed by the scaling and offset values for _MainTex in the Material inspector.

I have no idea why, but that works, so thank you.