边缘发光效果的两种写法

我们可以看到很多游戏经常会有这种模型边缘发光的效果，看起来很高大上的样子。其实实现起来挺简单的，网上也有很多这样的例子分享，现在我也来分享一下两种Shader实现的代码吧。

1.Surface Shader

 Shader "Custom/Rim Light" {
        Properties {
               _MainTex("Base (RGB)", 2D) = "white" {}
               _RimColor("_RimColor", Color) =(0.17,0.36,0.81,0.0)
               _RimWidth("_RimWidth", Range(0.6,9.0)) = 0.9
        }

        SubShader {
               Tags{ "RenderType" = "Opaque"}
               LOD 150

               CGPROGRAM

               #pragma surface surf Lambert

               struct Input {
                      float2 uv_MainTex;
                      float3 viewDir;
               };

               sampler2D _MainTex;
               fixed4 _RimColor;
               fixed _RimWidth;

               void surf (Input IN, inout SurfaceOutput o) {
                      fixed4 t = tex2D (_MainTex, IN.uv_MainTex);
                      o.Albedo = t.rgb;
                      o.Alpha = t.a;
                      half rim = 1.0 - saturate(dot (normalize(IN.viewDir), o.Normal));
                      o.Emission= _RimColor.rgb * pow (rim, _RimWidth);
               }

               ENDCG
        }

        Fallback "Diffuse"
 }

主要是这两句起到关键作用。

 half rim = 1.0 - saturate(dot (normalize(IN.viewDir), o.Normal));
 o.Emission= _RimColor.rgb * pow (rim, _RimWidth);

如果不想受灯光影响，可以在Tags加上"LightMode"="Always"

2.Vetex and Fragment Shader

 Shader "Custom/Rim Light VF" {
     Properties {
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _Color ("Main Color", Color) = (1,1,1,1)
         _RimColor ("Rim Color", Color) = (1, 1, 1, 1)
         _RimWidth ("Rim Width", float) = 0.9
     }
     SubShader {
         Pass {
             Lighting Off
             CGPROGRAM
                 #pragma vertex vert
                 #pragma fragment frag
                 #include "UnityCG.cginc"

                 struct appdata
                 {
                     float4 vertex : POSITION;
                     float3 normal : NORMAL;
                     float2 texcoord : TEXCOORD0;
                 };

                 struct v2f
                 {
                     float4 pos : SV_POSITION;
                     float2 uv : TEXCOORD0;
                     fixed3 color : COLOR;
                 };

                 uniform float4 _MainTex_ST;
                 uniform fixed4 _RimColor;
                 float _RimWidth;

                 v2f vert (appdata_base v) {
                     v2f o;
                     o.pos = mul (UNITY_MATRIX_MVP, v.vertex);

                     float3 viewDir = normalize(ObjSpaceViewDir(v.vertex));
                     float dotProduct = 1 - dot(v.normal, viewDir);

                     o.color = smoothstep(1 - _RimWidth, 1.0, dotProduct);
                     o.color *= _RimColor;

                     o.uv = v.texcoord.xy;
                     return o;
                 }

                 uniform sampler2D _MainTex;
                 uniform fixed4 _Color;

                 fixed4 frag(v2f i) : COLOR {
                     fixed4 texcol = tex2D(_MainTex, i.uv);
                     texcol *= _Color;
                     texcol.rgb += i.color;
                     return texcol;
                 }
             ENDCG
         }
     }
 }

当然最关键的还是vert方法里的代码，具体两种方法大家可以根据需求使用。看看效果，赶紧试试吧。