diffuse curve world shader

Code (CSharp):

1. Shader "Custom/CurvedWorld"
2. {
3. Properties {
4.     _MainTex ("Base (RGB)", 2D) = "white" {}
5. }
6. SubShader {
7.     Tags { "RenderType"="Opaque" }
8.     LOD 150
9.  
10. CGPROGRAM
11. #pragma surface surf Lambert noforwardadd  vertex:vert
12.  
13. sampler2D _MainTex;
14.  
15. struct Input {
16.     float2 uv_MainTex;
17. };
18.  
19. void surf (Input IN, inout SurfaceOutput o) {
20.     fixed4 c = tex2D(_MainTex, IN.uv_MainTex);
21.     o.Albedo = c.rgb;
22.     o.Alpha = c.a;
23. }
24.  
25. void vert( inout appdata_full v)
26.         {
27.         float4 _QOffset= float4(-5,-5,0,0);
28.         float _Dist=100.0;
29.         vv.xyz -= _WorldSpaceCameraPos.xyz;
30.           float4 vPos = mul (UNITY_MATRIX_MV, v.vertex);
31.                 float zOff = vPos.z/_Dist;
32.             vPos += _QOffset*zOff*zOff;
33.             v.vertex = mul (vPos, UNITY_MATRIX_IT_MV);
34.             v.texcoord = mul( UNITY_MATRIX_TEXTURE0, v.texcoord );    
35.         }
36. ENDCG
37. }
38.  
39.  
40. }

Hi all
I try to make a my objects to appear curved like Subway game, so I use this shader, it's working Editor, but doesn't produce any thing on Android device