unity shader漫反射中逐像素的光照模型

Shader "JK/DiffusePixelLevel" {
Properties {
_Diffuse ("diffuse", Color) = (1,1,1,1)
}
SubShader {
Pass{
Tags { "LightMode"="ForwardBase" }




CGPROGRAM
#pragma vertex vert 
#pragma fragment frag
#include "Lighting.cginc"


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


struct v2f{
float4 position:SV_POSITION;
float3 worldNormal:TEXCOORD0;
};


v2f vert(a2v v){
v2f o;
o.position = mul(UNITY_MATRIX_MVP, v.vertex);
o.worldNormal = normalize(mul(v.normal, (float3x3)_World2Object));
return o;
}


fixed4 frag(v2f i):SV_Target
{
fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;
fixed3 worldNormal = normalize(i.worldNormal);
fixed3 lightDir = normalize(_WorldSpaceLightPos0.xyz);
fixed3 diffuse = _LightColor0.rgb * _Diffuse.rgb * saturate(dot(worldNormal, lightDir));
fixed3 color = ambient + diffuse;
return fixed4(color, 1.0);
}


ENDCG
} 
}
FallBack "Diffuse"
}