Shader "Unlit URP Shader"
{
    Properties
    {
        _HeadColor("HeadColor",color)=(1,1,1,1)
        _TailColor("TailColor",color)=(1,1,1,1)
        _Value("Value",Range(0,1))=0.5
        
        _SpPow("SpPow",float)=1
        _SpScale("SpScale",float)=1
        
        _FPow("FPow",float)=1
        _FScale("Fscale",float)=1
    }
 
    SubShader
    {
        Tags { "Queue"="Transparent" "RenderType" = "Transparent" "RenderPipeline" = "UniversalPipeline" }
        LOD 100
 
        Pass
        {
            Name "Unlit"
            Tags { "LightMode"="UniversalForward"}
            Blend SrcAlpha OneMinusSrcAlpha
            HLSLPROGRAM
            // Required to compile gles 2.0 with standard srp library
            #pragma prefer_hlslcc gles
            #pragma exclude_renderers d3d11_9x
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_fog
            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Color.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"

            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS 
            #pragma multi_compile _ _MAIN_LIGHT_SHADOWS_CASCADE 
            #pragma multi_compile _ _SHADOWS_SOFT 
            #pragma multi_compile _ _ADDITIONAL_LIGHTS_VERTEX _ADDITIONAL_LIGHTS 
 
 
            struct Attributes
            {
                float4 positionOS       : POSITION;
                float2 uv               : TEXCOORD0;
                float3 normal:NORMAL;
                float3 wpos:TEXCOORD1;
            };
 
            struct Varyings
            {
                float4 positionCS       : SV_POSITION;
                float2 uv               : TEXCOORD0;
                float3 normal:TEXCOORD1;
                float3 wpos:TEXCOORD2;
            };
 
            CBUFFER_START(UnityPerMaterial)
            float _Value;
            float4 _HeadColor;
            float4 _TailColor;
            float _SpPow;
            float _SpScale;
            float _FPow;
            float _FScale;
            CBUFFER_END
            TEXTURE2D (_BaseMap);SAMPLER(sampler_BaseMap);
            
 
            Varyings vert(Attributes v)
            {
                Varyings o = (Varyings)0;
 
                o.positionCS = TransformObjectToHClip(v.positionOS.xyz);
                o.uv =v.uv;
                o.normal=TransformObjectToWorldNormal(v.normal);
                o.wpos=TransformObjectToWorld(v.positionOS);
 
                return o;
            }
 
            half4 frag(Varyings i) : SV_Target
            {
                half4 c;
                float3 LDir=normalize(_MainLightPosition);
                float3 VDir=normalize(_WorldSpaceCameraPos-i.wpos);
                float NdL=dot(i.normal,LDir)*0.5+0.5;
                float NdH=pow(saturate(dot(i.normal,normalize(LDir+VDir))),_SpPow)*_SpScale;
                float NdV=pow(saturate(dot(i.normal,VDir)),_FPow);

                float F=(1-NdV)*_FScale;
                
                
                c.rgba=lerp(_TailColor,_HeadColor,step(_Value,i.uv.y));
                float3 specular=c.rgb*NdH;
                c.rgb=c.rgb*NdL+specular+F.xxx;
                //c.rgb=F.xxxx;
                //c.rgb = MixFog(c.rgb, i.fogCoord);
                return c;
            }
            ENDHLSL
        }
    }
}