Rim 边缘光

边缘光：计算眼睛和模型顶点法线的点积，结果作为强度，和材质输出；顶点和法线平行时，强度最大，垂直时，强度最小。因此将他取反，即同一方向时，强度最小，垂直时，强度最大。

 float rim= 1-dot(normalize(viewDirection),normalDirection); 

源代码：

Shader "JQM/Rim_1"
{
    Properties
    {
        _Color("Color", color) = (1.0,1.0,1.0,1.0)
        _SpecColor("Specular Color", color) = (1.0,1.0,1.0,1.0)
        _Shininess("Shininess",float) = 10
        _RimColor("Rim Coloe Color", color) = (1.0,1.0,1.0,1.0)
        _RimPower("Rim Power",Range(0.1,10.0)) = 3.0

    }
    SubShader{
        Pass{
            
            Tags { "LightMode" = "ForwardBase"}

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            //使用自定义变量
            uniform float4 _Color;
            uniform float4 _SpecColor;
            uniform float4 _RimColor;
            uniform float _Shininess;
            uniform float _RimPower;

            //使用Unity定义的变量
            uniform float4 _LightColor0;

            struct vertexInput{
                float4 vertex:POSITION;
                float3 normal:NORMAL;
            };

            struct vertexOutput{
                float4 pos:SV_POSITION;
                float4 posWorld:TEXCOORD0;
                float3 normalDir:TEXCOORD1;
            };

            //顶点程序
            vertexOutput vert(vertexInput v)
            {
                vertexOutput o;
                o.posWorld = mul(_Object2World, v.vertex);
                o.normalDir =  normalize( mul(float4(v.normal,0.0),_World2Object).xyz);
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                return o;
            }

            //片段程序
            float4 frag(vertexOutput i):COLOR
            {
                float3 normalDirection = i.normalDir;
                float3 viewDirection = normalize(_WorldSpaceCameraPos.xyz- i.posWorld.xyz);
                
                float rim=1 -dot(normalize(viewDirection),normalDirection);
                return float4(rim*_Color.xyz,1.0);
            }

            ENDCG
        }
    }
    
}