//  Structs
struct Attributes
{
    float4 positionOS                   : POSITION;
    float3 normalOS                     : NORMAL;
    float4 tangentOS                    : TANGENT;
    float2 texcoord                     : TEXCOORD0;
    #if defined(LIGHTMAP_ON)
        float2 staticLightmapUV         : TEXCOORD1;
    #endif
    #ifdef DYNAMICLIGHTMAP_ON
        float2 dynamicLightmapUV        : TEXCOORD2;
    #endif
    #if defined(_USEVERTEXCOLORS)
        half4 color                     : COLOR;
    #endif
    UNITY_VERTEX_INPUT_INSTANCE_ID
};

struct Varyings
{
    float2 uv                           : TEXCOORD0;

    //#if defined(REQUIRES_WORLD_SPACE_POS_INTERPOLATOR)
        float3 positionWS               : TEXCOORD1;
    //#endif

    half3 normalWS                      : TEXCOORD2;
    
    #ifdef _NORMALMAP
    //#if defined(REQUIRES_WORLD_SPACE_TANGENT_INTERPOLATOR)
        half4 tangentWS                 : TEXCOORD3;    
    #endif

    #ifdef _ADDITIONAL_LIGHTS_VERTEX
        half4 fogFactorAndVertexLight   : TEXCOORD4; // x: fogFactor, yzw: vertex light
    #else
        half  fogFactor                 : TEXCOORD4;
    #endif

    #if defined(REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR)
        float4 shadowCoord              : TEXCOORD5;
    #endif

    DECLARE_LIGHTMAP_OR_SH(staticLightmapUV, vertexSH, 6);

    #ifdef DYNAMICLIGHTMAP_ON
        float2  dynamicLightmapUV       : TEXCOORD7;
    #endif

    #if defined(_USEVERTEXCOLORS)
        half4 color                     : COLOR;
    #endif
    
    float4 positionCS                   : SV_POSITION;
    
    //UNITY_VERTEX_INPUT_INSTANCE_ID
    UNITY_VERTEX_OUTPUT_STEREO
};

// Include the surface function
#include "Includes/Lux URP MeshTerrain SurfaceData.hlsl"

Varyings vert (Attributes input)
{
    Varyings output = (Varyings)0;
    UNITY_SETUP_INSTANCE_ID(input);
    //UNITY_TRANSFER_INSTANCE_ID(input, output);
    UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);

    VertexPositionInputs vertexInput = GetVertexPositionInputs(input.positionOS.xyz);
    VertexNormalInputs normalInput = GetVertexNormalInputs(input.normalOS, input.tangentOS);
    
    half3 vertexLight = VertexLighting(vertexInput.positionWS, normalInput.normalWS);
    half fogFactor = ComputeFogFactor(vertexInput.positionCS.z);

    output.uv = input.texcoord; //TRANSFORM_TEX(input.texcoord, _BaseMap);
    //  Already normalized from normal transform to WS.
    output.normalWS = normalInput.normalWS;
    //#if defined(REQUIRES_WORLD_SPACE_TANGENT_INTERPOLATOR)
    #ifdef _NORMALMAP
        real sign = input.tangentOS.w * GetOddNegativeScale();
        output.tangentWS = half4(normalInput.tangentWS.xyz, sign);
    #endif
    
    OUTPUT_LIGHTMAP_UV(input.staticLightmapUV, unity_LightmapST, output.staticLightmapUV);
    #ifdef DYNAMICLIGHTMAP_ON
        output.dynamicLightmapUV = input.dynamicLightmapUV.xy * unity_DynamicLightmapST.xy + unity_DynamicLightmapST.zw;
    #endif
    OUTPUT_SH(output.normalWS.xyz, output.vertexSH);
    #ifdef _ADDITIONAL_LIGHTS_VERTEX
        output.fogFactorAndVertexLight = half4(fogFactor, vertexLight);
    #else
        output.fogFactor = fogFactor;
    #endif

    //#if defined(REQUIRES_WORLD_SPACE_POS_INTERPOLATOR)
        output.positionWS = vertexInput.positionWS;
    //#endif

    #if defined(REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR)
        output.shadowCoord = GetShadowCoord(vertexInput);
    #endif

    #if defined(_USEVERTEXCOLORS)
        output.color = input.color;
    #endif

    output.positionCS = vertexInput.positionCS;

    return output;
}

half4 frag (Varyings input ) : SV_Target
{
    //UNITY_SETUP_INSTANCE_ID(input);
    UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);

    SurfaceData surfaceData;
    half3 topdownNormal;
    half topnormalstrength;

//  Get the surface description
    InitializeStandardLitSurfaceData(input, surfaceData, topdownNormal);

//  Transfer all to world space 
    InputData inputData = (InputData)0;
    inputData.positionWS = input.positionWS;

    half3 viewDirWS = GetWorldSpaceNormalizeViewDir(input.positionWS);
    #ifdef _NORMALMAP
        #if !defined(_TOPDOWNPROJECTION)
            float sgn = input.tangentWS.w;      // should be either +1 or -1
            float3 bitangent = sgn * cross(input.normalWS.xyz, input.tangentWS.xyz);
            inputData.normalWS = TransformTangentToWorld(surfaceData.normalTS, half3x3(input.tangentWS.xyz, bitangent.xyz, input.normalWS.xyz));
        #else
            inputData.normalWS = surfaceData.normalTS;
        #endif
    #else
        inputData.normalWS = input.normalWS;
    #endif

    inputData.normalWS = NormalizeNormalPerPixel(inputData.normalWS);
    inputData.viewDirectionWS = viewDirWS;

    #if defined(REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR)
        inputData.shadowCoord = input.shadowCoord;
    #elif defined(MAIN_LIGHT_CALCULATE_SHADOWS)
        inputData.shadowCoord = TransformWorldToShadowCoord(inputData.positionWS);
    #else
        inputData.shadowCoord = float4(0, 0, 0, 0);
    #endif

    #ifdef _ADDITIONAL_LIGHTS_VERTEX
        inputData.fogCoord = InitializeInputDataFog(float4(input.positionWS, 1.0), input.fogFactorAndVertexLight.x);
        inputData.vertexLighting = input.fogFactorAndVertexLight.yzw;
    #else
        inputData.fogCoord = InitializeInputDataFog(float4(input.positionWS, 1.0), input.fogFactor);
    #endif

    #if defined(DYNAMICLIGHTMAP_ON)
        inputData.bakedGI = SAMPLE_GI(input.staticLightmapUV, input.dynamicLightmapUV, input.vertexSH, inputData.normalWS);
    #else
        inputData.bakedGI = SAMPLE_GI(input.staticLightmapUV, input.vertexSH, inputData.normalWS);
    #endif

    inputData.normalizedScreenSpaceUV = GetNormalizedScreenSpaceUV(input.positionCS);
    inputData.shadowMask = SAMPLE_SHADOWMASK(input.staticLightmapUV);

    #if defined(DEBUG_DISPLAY)
    #if defined(DYNAMICLIGHTMAP_ON)
    inputData.dynamicLightmapUV = input.dynamicLightmapUV;
    #endif
    #if defined(LIGHTMAP_ON)
    inputData.staticLightmapUV = input.staticLightmapUV;
    #else
    inputData.vertexSH = input.vertexSH;
    #endif
    #endif

#ifdef _DBUFFER
    #if defined(_RECEIVEDECALS)
        ApplyDecalToSurfaceData(input.positionCS, surfaceData, inputData);
    #endif
#endif

    half4 color = UniversalFragmentPBR(inputData, surfaceData);

//  Computes fog factor per-vertex
    color.rgb = MixFog(color.rgb, inputData.fogCoord);

    return color;
}