Shader "Custom/StencilObjectHDRP"
{
    Properties
    {
        _BaseColor("Base Color", Color) = (1,1,1,1)
        _MainTex("Albedo (RGB)", 2D) = "white" {}
        _NormalMap("Normal Map", 2D) = "bump" {}
        _NormalStrength("Normal Strength", Range(0,2)) = 1
        _Metallic("Metallic", Range(0,1)) = 0.0
        _Smoothness("Smoothness", Range(0,1)) = 0.5
    }
    SubShader
    {
        Tags { "RenderPipeline"="HDRenderPipeline" "RenderType"="Opaque" "Queue"="Geometry" }

        Pass
        {
            Name "ForwardLit"
            Tags { "LightMode"="ForwardOnly" }

            Stencil
            {
                Ref 1
                Comp Equal  
                Pass Keep
            }

            ZTest Always    
            Cull Back       

            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma target 4.5
            #pragma multi_compile _ NORMALMAP

            #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Lit/Lit.hlsl"
            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Builtin/BuiltinData.hlsl"
            #include "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/MaterialUtilities.hlsl"

            float3 GetIndexColor(int index)
            {
                float3 colors[5] = {
                    float3(1, 0, 0),  // Red
                    float3(0, 1, 0),  // Green
                    float3(0, 0, 1),  // Blue
                    float3(1, 1, 0),  // Yellow
                    float3(1, 0, 1)   // Magenta
                };
                return colors[index % 5];
            }

            struct Attributes
            {
                float4 positionOS : POSITION;
                float2 uv : TEXCOORD0;
                float3 normalOS : NORMAL;
                float4 tangentOS : TANGENT;
            };

            struct Varyings
            {
                float4 positionCS : SV_POSITION;
                float2 uv : TEXCOORD0;
                float3 normalWS : TEXCOORD1;
                float3 tangentWS : TEXCOORD2;
                float3 bitangentWS : TEXCOORD3;
            };

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);
            TEXTURE2D(_NormalMap);
            SAMPLER(sampler_NormalMap);

            float4 _BaseColor;
            float _NormalStrength;
            float _Metallic;
            float _Smoothness;

            Varyings vert(Attributes IN)
            {
                Varyings OUT;
                OUT.positionCS = TransformObjectToHClip(IN.positionOS.xyz);
                OUT.uv = IN.uv;
                OUT.normalWS = TransformObjectToWorldNormal(IN.normalOS);
                OUT.tangentWS = TransformObjectToWorldDir(IN.tangentOS.xyz);
                OUT.bitangentWS = cross(OUT.normalWS, OUT.tangentWS) * IN.tangentOS.w;
                return OUT;
            }

            half4 frag(Varyings IN) : SV_Target
            {
                float4 albedo = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, IN.uv) * _BaseColor;

                float3 normalTS = UnpackNormal(SAMPLE_TEXTURE2D(_NormalMap, sampler_NormalMap, IN.uv));
                normalTS.xy *= _NormalStrength;
                normalTS.z = sqrt(1.0 - saturate(dot(normalTS.xy, normalTS.xy)));

                float3 normalWS = normalize(
                    normalTS.x * IN.tangentWS +
                    normalTS.y * IN.bitangentWS +
                    normalTS.z * IN.normalWS
                );

                BuiltinData builtinData;
                ZERO_INITIALIZE(BuiltinData, builtinData);
                SurfaceData surfaceData;
                ZERO_INITIALIZE(SurfaceData, surfaceData);

                surfaceData.baseColor = albedo.rgb;
                surfaceData.normalWS = normalWS;
                surfaceData.perceptualSmoothness = _Smoothness;
                surfaceData.metallic = _Metallic;
                surfaceData.ambientOcclusion = 1.0;
                surfaceData.specularColor = 0.5.xxx;

                BSDFData bsdfData = ConvertSurfaceDataToBSDFData(surfaceData);
                builtinData.color = EvaluateBSDF(bsdfData, normalWS);

                return half4(builtinData.color, 1.0);
            }
            ENDHLSL
        }
    }
}