rim shader

Shader "zff/Rim"
{
    Properties
    {
        _MainTex("Texture",2D)="white"{}
        _BumpMap("Bumpmap",2D)="bump"{}
        _RimColor("Rim Color",Color)=(0.26,0.19,0.16,0)
        _RimPower("Rim Power",Range(0.5,8.0))=3.0
    }
    SubShader
    {
        Tags{"RenderType"="Opaque"}
        CGPROGRAM
        #pragma surface surf Lambert
        struct Input
        {
            float2 uv_MainTex;
            float2 uv_BumpTex;
            float3 viewDir;
        };
        sampler2D _MainTex;
        sampler2D _BumpTex;
        float4 _RimColor;
        float _RimPower;
        void surf(Input IN,inout SurfaceOutput o)
        {
            o.Albedo = tex2D(_Maintex,IN.uv_MainTex).rgb;
            o.Normal = UnpackNormal(tex2D(_BumpMap,IN.uv_BumpTex));
            half rim = 1.0 - saturate(dot(normalize(IN.viewDir),o.Normal));
            o.Emission = _RimColor.rgb * pow(rim,_RimPower);//自發光強度
        }
        ENDCG
    }
    Fallback "Diffuse"
}

saturate飽和處理，大於1就變成1，小於0就變成0
normalize 獲得單位向量