unity shader 较完整光照（含有多光源阴影）

效果图：
shader被附给了球。
灯光需要在属性面板开启阴影。

// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Unlit/lightFull"
{
	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
	}
	SubShader
	{
		Tags { "RenderType"="Opaque" }
		LOD 100

		Pass
		{
			Tags{"LightMode" = "ForwardBase"}
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			// make fog work
			#pragma multi_compile_fwdbase
			
			#include "UnityCG.cginc"
			#include "Lighting.cginc"
			#include "AutoLight.cginc"
			struct appdata
			{
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
				float3 normal : NORMAL;
			};

			struct v2f
			{
				float2 uv : TEXCOORD0;
				float4 pos : POSITION;
				float4 pos_world : TEXCOORD1;
				float3 normal:TEXCOORD2;
				SHADOW_COORDS(3)
			};

			sampler2D _MainTex;
			float4 _MainTex_ST;
			
			v2f vert (appdata v)
			{
				v2f o;
				o.pos_world = mul(UNITY_MATRIX_M, v.vertex);
				o.normal = v.normal;
				o.pos = UnityObjectToClipPos(v.vertex);
				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
				TRANSFER_SHADOW(o);
				return o;
			}
			
			fixed4 frag (v2f i) : SV_Target
			{
				// sample the texture
				fixed4 col = tex2D(_MainTex, i.uv);
				float4 lightColor = _LightColor0;
				float3 lightDir = WorldSpaceLightDir(i.pos_world);
				UNITY_LIGHT_ATTENUATION(atten, i, i.pos_world.xyz);
				return col * lightColor * saturate(dot(lightDir, i.normal)) * atten;
			}
			ENDCG
		}
		pass
		{
			Tags{"LightMode" = "ForwardAdd"}
			Blend One One
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#pragma multi_compile_fwdadd_fullshadows
				
			#include "UnityCG.cginc"
			#include "Lighting.cginc"
			#include "AutoLight.cginc"
			struct v2f
			{
				float4 pos : POSITION;
				float4 vertex : TEXCOORD0;
				float3 normal : NORMAL;
				SHADOW_COORDS(2)
			};

			v2f vert(appdata_full data)
			{
				v2f v;
				v.pos = UnityObjectToClipPos(data.vertex);
				v.vertex = mul(UNITY_MATRIX_M, data.vertex);
				v.normal = data.normal;
				TRANSFER_SHADOW(v);
				return v;
			}

			float4 frag(v2f v) :SV_Target
			{
				float3 lightColor = _LightColor0;
#ifdef USING_DIRECTIONAL_LIGHT
				float3 lightDir = _WorldSpaceLightPos0;
#else
				float3 lightDir = _WorldSpaceLightPos0 - v.vertex;
#endif
				UNITY_LIGHT_ATTENUATION(atten, v, v.vertex.xyz);
				float3 color =  lightColor * saturate(dot(lightDir, v.normal) * atten);
				return float4(color, 1);
			}
			ENDCG
		}
	}
	Fallback "Specular"
}