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
}
}

}