lambert光照

lambert光照模型是：光线角度向量dot物体法线向量，得到光照亮度。

Shader "Unlit/shader2"
{
Properties
{
_MainTex ("Texture", 2D) = "white" {}
_LightDir("Light",Vector)=(1,0,0,0)
_Intensity("Intensity",float)=1
}
SubShader
{
Tags { "RenderType"="Opaque" }
LOD 100


Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
// make fog work
#pragma multi_compile_fog

#include "UnityCG.cginc"


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


struct v2f
{
float2 uv : TEXCOORD0;
UNITY_FOG_COORDS(1)
float4 vertex : SV_POSITION;
float3 normal : NORMAL;
};


sampler2D _MainTex;
float4 _MainTex_ST;
float4 _LightDir;
float _Intensity;


v2f vert (appdata v)
{
v2f o;
o.vertex = UnityObjectToClipPos(v.vertex);
o.uv = TRANSFORM_TEX(v.uv, _MainTex);
UNITY_TRANSFER_FOG(o,o.vertex);
o.normal=v.normal;
return o;
}

float4 frag (v2f i) : SV_Target
{
// sample the texture
float4 col = tex2D(_MainTex, i.uv);
float3 lightdir=normalize(_LightDir);
float v= dot(lightdir,i.normal);
col= col* float4(v,v,v,1)*_Intensity;

return col;
}
ENDCG
}
}
}