#ifndef UNIVERSAL_SIMPLELIT_GBUFFER_PASS_INCLUDED
#define UNIVERSAL_SIMPLELIT_GBUFFER_PASS_INCLUDED

#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Lighting.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/UnityGBuffer.hlsl"
#if defined(LOD_FADE_CROSSFADE)
    #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/LODCrossFade.hlsl"
#endif

// keep this file in sync with LitForwardPass.hlsl

struct Attributes
{
    float4 positionOS   : POSITION;
    float3 normalOS     : NORMAL;
    float4 tangentOS    : TANGENT;
    float2 texcoord     : TEXCOORD0;
    float2 staticLightmapUV   : TEXCOORD1;
    float2 dynamicLightmapUV  : TEXCOORD2;
    UNITY_VERTEX_INPUT_INSTANCE_ID
};

struct Varyings
{
    float2 uv                       : TEXCOORD0;

    float3 posWS                    : TEXCOORD1;    // xyz: posWS

    #ifdef _NORMALMAP
        half4 normal                   : TEXCOORD2;    // xyz: normal, w: viewDir.x
        half4 tangent                  : TEXCOORD3;    // xyz: tangent, w: viewDir.y
        half4 bitangent                : TEXCOORD4;    // xyz: bitangent, w: viewDir.z
    #else
        half3  normal                  : TEXCOORD2;
    #endif

    #ifdef _ADDITIONAL_LIGHTS_VERTEX
        half3 vertexLighting            : TEXCOORD5; // xyz: vertex light
    #endif

    #if defined(REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR)
        float4 shadowCoord              : TEXCOORD6;
    #endif

    DECLARE_LIGHTMAP_OR_SH(staticLightmapUV, vertexSH, 7);
#ifdef DYNAMICLIGHTMAP_ON
    float2  dynamicLightmapUV : TEXCOORD8; // Dynamic lightmap UVs
#endif

#ifdef USE_APV_PROBE_OCCLUSION
    float4 probeOcclusion : TEXCOORD9;
#endif

    float4 positionCS               : SV_POSITION;
    UNITY_VERTEX_INPUT_INSTANCE_ID
    UNITY_VERTEX_OUTPUT_STEREO
};

void InitializeInputData(Varyings input, half3 normalTS, out InputData inputData)
{
    inputData = (InputData)0;

    inputData.positionWS = input.posWS;
    inputData.positionCS = input.positionCS;

    #ifdef _NORMALMAP
        half3 viewDirWS = half3(input.normal.w, input.tangent.w, input.bitangent.w);
        inputData.normalWS = TransformTangentToWorld(normalTS,half3x3(input.tangent.xyz, input.bitangent.xyz, input.normal.xyz));
    #else
        half3 viewDirWS = GetWorldSpaceNormalizeViewDir(inputData.positionWS);
        inputData.normalWS = input.normal;
    #endif

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

    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.vertexLighting = input.vertexLighting.xyz;
    #else
        inputData.vertexLighting = half3(0, 0, 0);
    #endif

    inputData.fogCoord = 0; // we don't apply fog in the gbuffer pass
    inputData.normalizedScreenSpaceUV = GetNormalizedScreenSpaceUV(input.positionCS);

    #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
    #if defined(USE_APV_PROBE_OCCLUSION)
    inputData.probeOcclusion = input.probeOcclusion;
    #endif
    #endif
}

void InitializeBakedGIData(Varyings input, inout InputData inputData)
{
#if defined(DYNAMICLIGHTMAP_ON)
    inputData.bakedGI = SAMPLE_GI(input.staticLightmapUV, input.dynamicLightmapUV, input.vertexSH, inputData.normalWS);
    inputData.shadowMask = SAMPLE_SHADOWMASK(input.staticLightmapUV);
#elif !defined(LIGHTMAP_ON) && (defined(PROBE_VOLUMES_L1) || defined(PROBE_VOLUMES_L2))
    inputData.bakedGI = SAMPLE_GI(input.vertexSH,
        GetAbsolutePositionWS(inputData.positionWS),
        inputData.normalWS,
        inputData.viewDirectionWS,
        inputData.positionCS.xy,
        input.probeOcclusion,
        inputData.shadowMask);
#else
    inputData.bakedGI = SAMPLE_GI(input.staticLightmapUV, input.vertexSH, inputData.normalWS);
    inputData.shadowMask = SAMPLE_SHADOWMASK(input.staticLightmapUV);
#endif
}

///////////////////////////////////////////////////////////////////////////////
//                  Vertex and Fragment functions                            //
///////////////////////////////////////////////////////////////////////////////

// Used in Standard (Simple Lighting) shader
Varyings LitPassVertexSimple(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);

    output.uv = TRANSFORM_TEX(input.texcoord, _BaseMap);
    output.posWS.xyz = vertexInput.positionWS;
    output.positionCS = vertexInput.positionCS;

    #ifdef _NORMALMAP
        half3 viewDirWS = GetWorldSpaceNormalizeViewDir(vertexInput.positionWS);
        output.normal = half4(normalInput.normalWS, viewDirWS.x);
        output.tangent = half4(normalInput.tangentWS, viewDirWS.y);
        output.bitangent = half4(normalInput.bitangentWS, viewDirWS.z);
    #else
        output.normal = NormalizeNormalPerVertex(normalInput.normalWS);
    #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_SH4(vertexInput.positionWS, output.normal.xyz, GetWorldSpaceNormalizeViewDir(vertexInput.positionWS), output.vertexSH, output.probeOcclusion);

    #ifdef _ADDITIONAL_LIGHTS_VERTEX
        half3 vertexLight = VertexLighting(vertexInput.positionWS, normalInput.normalWS);
        output.vertexLighting = vertexLight;
    #endif

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

    return output;
}



// Used for StandardSimpleLighting shader
FragmentOutput LitPassFragmentSimple(Varyings input)
{
    UNITY_SETUP_INSTANCE_ID(input);
    UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);

    SurfaceData surfaceData;
    InitializeSimpleLitSurfaceData(input.uv, surfaceData);

#ifdef LOD_FADE_CROSSFADE
    LODFadeCrossFade(input.positionCS);
#endif

    InputData inputData;
    InitializeInputData(input, surfaceData.normalTS, inputData);
    SETUP_DEBUG_TEXTURE_DATA(inputData, UNDO_TRANSFORM_TEX(input.uv, _BaseMap));

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

    InitializeBakedGIData(input, inputData);

    Light mainLight = GetMainLight(inputData.shadowCoord, inputData.positionWS, inputData.shadowMask);
    MixRealtimeAndBakedGI(mainLight, inputData.normalWS, inputData.bakedGI, inputData.shadowMask);
    half4 color = half4(inputData.bakedGI * surfaceData.albedo + surfaceData.emission, surfaceData.alpha);

    return SurfaceDataToGbuffer(surfaceData, inputData, color.rgb, kLightingSimpleLit);
};

#endif