Simple metalness and glossiness standard light shader.

I want to make a simle shader that used a metalness and glossiness map on it. With minimum code. I wrote this, but it doesnot work:

Code (CSharp):

1. Shader "Custom/StructShader" {
2.     Properties {
3.         _MainTex ("A (RGB)", 2D) = "white" {}
4.         _MS ("MS", 2D) = "black" {}
5.     }
6.     SubShader {
7.         Tags { "RenderType"="Opaque" }
8.         LOD 200
9.        
10.         CGPROGRAM
11.  
12.         #pragma surface surf Standard fullforwardshadows
13.  
14.         #pragma target 3.0
15.  
16.         sampler2D _MainTex;
17.         sampler2D _MS;
18.  
19.         struct Input {
20.             float2 uv_MainTex;
21.             float2 uv_MS;
22.         };
23.  
24.         // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
25.         // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
26.         // #pragma instancing_options assumeuniformscaling
27.         UNITY_INSTANCING_CBUFFER_START(Props)
28.             // put more per-instance properties here
29.         UNITY_INSTANCING_CBUFFER_END
30.  
31.         void surf (Input IN, inout SurfaceOutputStandard o) {
32.  
33.             fixed4 c = tex2D (_MainTex, IN.uv_MainTex);
34.             o.Albedo = c.rgb;
35.  
36.             fixed4 ms = tex2D(_MainTex, IN.uv_MS);
37.             o.Metallic = ms.r;
38.             o.Smoothness = ms.g;
39.             o.Alpha = c.a;
40.         }
41.         ENDCG
42.     }
43.     FallBack "Diffuse"
44. }
45.  

What is wrong?

 

You're sampling the _MainTex texture twice, that should be _MS there.