Unity3D 边缘高光Shader

Shader "Custom/NewShader" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _RimColor("Rim Color", Color) = (,,,)
        _RimPower ("Rim power",range(,)) = //边缘强度
    }
    SubShader {
        Pass
        {

        CGPROGRAM

        #include "UnityCG.cginc"

        struct v2f
        {
            float4 vertex:POSITION;
            float2 uv:TEXCOORD0;
            float4 rim:COLOR;
        };

        sampler2D _MainTex;
        float4 _RimColor;
        float _RimPower;

        v2f vert(appdata_base  v)
        {
            v2f o;
            o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
            o.uv = v.texcoord;
            float3 worldPos = mul(_Object2World, v.vertex).xyz;
            float3 viewdir = normalize((_WorldSpaceCameraPos - worldPos));
            float3 normal = normalize(mul((float3x3)_Object2World,v.normal));

            o.rim.x = -saturate(dot(viewdir,normal));

            return o;
        }

        fixed4 frag (v2f IN):COLOR
        {
            fixed4  c = tex2D(_MainTex, IN.uv);
            c.rgb+= pow(IN.rim.x,)*_RimColor*_RimPower;
            return c;
        }

        #pragma vertex vert
        #pragma fragment frag

        ENDCG
        }
    }
    FallBack "Diffuse"
}