Unity basic lighting model

Shader "Unlit/NewUnlitShader"
{
    
 Properties
	{
    
        _Color("color1",Color)=(1,1,0,1)
		_BaseMap("Base Map",2D)="white" {
    }
		_Shininess("shininess",float)=32
	

	
    	
	
	}
	
	SubShader
	{
    
		Pass //pass You can use more than one pass
		{
    
	     HLSLPROGRAM //HLSL Can be replaced by GLSL

		#pragma vertex Vertex // Declare functions  // Vertex shader 
		#pragma fragment Pixel // Fragment Shader   Pixel shader 

	     half4 _Color;// Declare variables 
	     sampler2D _BaseMap;
	     float _Shininess;
	     

	     
	     //model Transform the local space of an object into world space 
	     //view  Through the change matrix of the camera, from the world space to the camera space 
	     //projection  Projection transformation to screen space 

	     #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
	     
	     #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

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

	      struct Varyings
        {
    
        	float4 positionCS:SV_POSITION;
        	float2  uv : TEXCOORD0;
	      	float3  normalWS: NORMAL;// The normal vector is a float3
	        float3  positionWS : TEXCOORD1;// Define a world space location 
        };
	     
	  
	     Varyings Vertex(Attributes IN)  // Vertex shader  float4 The type of variable entered  vertex Variable name 
	     //: Later, we will talk about the clipping space position associated with the vertex shader  SV It means system value Values in the system 
		{
    
            Varyings OUT;
	    	//IN.uv=IN.uv*_CosTime; //UV Over time 
			
			OUT.positionCS=TransformObjectToHClip(IN.vertex.xyz);
	     	OUT.normalWS=TransformObjectToWorld(IN.normal);// This is for direct use URP Inside TransformObjectToWorld
	     	OUT.positionWS=mul(UNITY_MATRIX_M,float4(IN.vertex.xyz,1.0));
	     	OUT.uv=IN.uv;// If you don't need to UV Make changes with input uv
	     	// The normal transformation matrix can be omitted   Because normals change due to scaling, the normal change matrix is particularly important 
			
            return OUT;
	    }
	     
	     

	     //lambert The lighting model has only ambient lighting and diffuse reflection 
	     //phong The model has one more highlight 
		half4 Pixel(Varyings IN) : SV_TARGET //SV It means system value
	     //SV_TARGET Indicates the color of the last pixel output 
	    {
    
	    	half4 color;
	    	Light lighting=GetMainLight();// This function can also be used to directly obtain the information of light 
	    	float3 normal=normalize(IN.normalWS);
	    	float3 viewDir=-normalize(_WorldSpaceCameraPos.xyz-normal);
	    	float3 reflDir=reflect(lighting.direction,normal);
	    	half3 ambient =SampleSH(normal)*0.02;// This SampleSH Spherical harmonics can sample the information of the surrounding environment 
	    	float diffuse=max(0,dot(normal,lighting.direction));// Directly through lighting Function to get the directional light   And light color 
	    	//float3 normalWS=normalize(IN.normalWS);// Get normal position 
	    	//float3 diffuse=max(0,dot(normalWS,_MainLightPosition.xyz));//_MainLightPosition Get the position of the light , We know that the smaller the angle between two unit vectors , The result of their dot multiplication tends to 1, The more affected by the light 
            float3 spec=max(0,dot(viewDir,reflDir));
        	spec=pow(spec,32);
	    

	    	
	    	color.rgb=tex2D(_BaseMap,IN.uv).rgb*_Color*diffuse*lighting.color.rgb+ambient+spec;
	    	color.a=1.0;
	    	return color;
	    }
		ENDHLSL
	    }
	
	
	}
}