A mobile decal shadow shader for Unity

MobileDecalShadow.shader

Shader "Mobile/Decal Shadow" {
	Properties{
		_MainTex("Base (RGB)", 2D) = "white" {}
		_alpha("AlphaMulti", Range(0,1)) = 1
	}
		SubShader{
		  Tags { "RenderType" = "Opaque" "Queue" = "Geometry+1" "ForceNoShadowCasting" = "True" }
		  LOD 200
		  Offset -1, -1

		  CGPROGRAM
		  #pragma surface surf Lambert decal:blend

		  sampler2D _MainTex;
		  float _alpha;

		  struct Input {
			float2 uv_MainTex;
			float3 viewDir;
		  };

		  void surf(Input IN, inout SurfaceOutput o) {
			half4 c = tex2D(_MainTex, IN.uv_MainTex);
			o.Albedo = c.rgb;
			o.Alpha = c.a * _alpha * sqrt(dot(normalize(IN.viewDir), o.Normal));
		  }
		  ENDCG
	}
}