三种光照模型的shader实现

Shader "Custom/Blinn_Phong" {
Properties {
_Diffuse("Diffuse",Color)=(1,1,1,1)
_Specular("Specular",COlor)=(1,1,1,1)
_Gloss("Gloss",Range(8.0,256))=20
}
SubShader {
Tags { "LightMode"="ForwardBase" }
Pass{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include"Lighting.cginc"

fixed4 _Diffuse;
fixed4 _Specular;
float  _Gloss;
struct a2v
{
float4 vertex:POSITION;
float3 normal:NORMAL;
};

struct v2f
{
float4 pos:SV_POSITION;
fixed3 worldNormal:TexCOORD0;
float3 worldPos:TEXCOORD1;
};
v2f vert(a2v v)
{
v2f o;
o.pos=mul(UNITY_MATRIX_MVP,v.vertex);
o.worldNormal=mul(v.normal,(float3x3)unity_WorldToObject);
o.worldPos=mul(unity_ObjectToWorld,v.vertex).xyz;
return o;
}

fixed4 frag(v2f i):SV_Target
{
fixed3 ambient=UNITY_LIGHTMODEL_AMBIENT.xyz;
fixed3 worldNormal=normalize(i.worldNormal);
fixed3 worldLightDir=normalize(_WorldSpaceLightPos0.xyz);
fixed3 diffuse=_LightColor0.rgb*_Diffuse.rgb*saturate(dot(worldNormal,worldLightDir));
//fixed3 reflectDir=normalize(reflect(-worldLightDir,worldNormal));
fixed3 viewDir=normalize(_WorldSpaceCameraPos.xyz-i.worldPos.xyz);
fixed3 halfDir=normalize(worldLightDir+viewDir);
fixed3 specular=_LightColor0.rgb*_Specular.rgb*pow(saturate(dot(worldNormal,halfDir)),_Gloss);
return fixed4(ambient+diffuse+specular,1.0);
}
ENDCG
}
}
FallBack "Specular"
}