Bumped anisotropic lighting

I've ported the anisotropic lighting shader from the wiki to a surface shader - works fine. Wanted to create a bumped version, but I get a lot of artifacts on the surface, anyone know why?

Code (csharp):

1. Shader "Metervara/Anisotropic Bump" {
2.     Properties {
3.         _Color ("Main Color", Color) = (1,1,1,1)
4.         _MainTex ("Base (RGB)", 2D) = "white" {}
5.         _AnisoTex ("Aniso lookup (RGBA)", 2D) = "white" {}
6.         _BumpMap ("Normalmap", 2D) = "bump" {}
7.     }
8.     SubShader {
9.         Tags { "RenderType" = "Opaque" }
10.         CGPROGRAM
11.         #pragma surface surf Anisotropic
12.        
13.         sampler2D _AnisoTex;
14.      
15.         half4 LightingAnisotropic (SurfaceOutput s, half3 lightDir, half3 viewDir, half atten) {
16.            
17.             half3 halfAngle = normalize(viewDir + lightDir);
18.            
19.             float2 uvA;
20.             uvA.x = dot(lightDir,s.Normal);
21.             uvA.y = dot(halfAngle,s.Normal);
22.            
23.             half4 aniso = tex2D( _AnisoTex, uvA );
24.            
25.             half4 c;
26.             c.rgb = s.Albedo * _LightColor0.rgb * aniso.rgb * (aniso.a * atten * 2);
27.             c.a = s.Alpha;
28.             return c;
29.     }
30.  
31.     struct Input {
32.         float2 uv_MainTex;
33.         float2 uv_BumpMap;
34.     };
35.      
36.     sampler2D _MainTex;
37.     sampler2D _BumpMap;
38.     fixed4 _Color;
39.      
40.     void surf (Input IN, inout SurfaceOutput o) {
41.         o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb * _Color;
42.         o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
43.     }
44.     ENDCG
45.   }
46.   Fallback "Diffuse"
47. }

 

Turning mip-maps off for the Anisotropic Lookup texture fixed it. Yay!