#ifndef XPBR_LIT_BASE
#define XPBR_LIT_BASE

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

CBUFFER_START(UnityPerMaterial)
float4	_MainTex_ST;
half4	_BaseColor;
half	_Cutoff;
half	_Metallic;
half	_Roughness;
half	_AO;
CBUFFER_END
half _XRuntimeAmbientEnabled;
half4 _XRuntimeAmbientSky;
half4 _XRuntimeAmbientEquator;
half4 _XRuntimeAmbientGround;
TEXTURE2D(_MainTex);    SAMPLER(sampler_MainTex);
TEXTURE2D(_MixTex);     SAMPLER(sampler_MixTex);


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

struct Varyings
{
	float2 uv                       : TEXCOORD0;
	DECLARE_LIGHTMAP_OR_SH(staticLightmapUV, vertexSH, 1);

	float3 positionWS               : TEXCOORD2;

	half4 normalWS                 : TEXCOORD3;    // xyz: normal, w: viewDir.x
	half4 tangentWS                : TEXCOORD4;    // xyz: tangent, w: viewDir.y
	half4 bitangentWS              : TEXCOORD5;    // xyz: bitangent, w: viewDir.z

#ifdef _ADDITIONAL_LIGHTS_VERTEX
    half4 fogFactorAndVertexLight   : TEXCOORD6; // x: fogFactor, yzw: vertex light
#else
    half  fogFactor                 : TEXCOORD6;
#endif

#ifdef DYNAMICLIGHTMAP_ON
	float2 dynamicLightmapUV        : TEXCOORD7;
#endif

	float4 positionCS               : SV_POSITION;
    #if defined(REQUIRES_VERTEX_SHADOW_COORD_INTERPOLATOR)
        float4 shadowCoord : TEXCOORD8;
    #endif

	UNITY_VERTEX_INPUT_INSTANCE_ID
		UNITY_VERTEX_OUTPUT_STEREO
};

//解码 RG 两通道球面映射压缩法线（有符号，ModelTranslator 工具编码：enc = n.xy/sqrt(2*(1+n.z)) * 0.5 + 0.5）
float3 DecodeSphereMap(float2 encoded)
{
    encoded = encoded * 2.0 - 1.0;    //rg 无符号存储，重映射回有符号
    float4 nn = float4(encoded, 1, -1);
    float l = dot(nn.xyz, -nn.xyw);
    nn.z = l;
    nn.xy *= sqrt(l);
    return nn.xyz * 2 + float3(0, 0, -1);
}

half3 SampleXRuntimeAmbient(half3 normalWS)
{
    half y = normalize(normalWS).y;
    half useGlobal = step(0.5h, _XRuntimeAmbientEnabled);
    half3 sky = lerp(half3(1.353h, 1.452h, 1.568h), _XRuntimeAmbientSky.rgb, useGlobal);
    half3 equator = lerp(half3(1.023h, 1.122h, 1.254h), _XRuntimeAmbientEquator.rgb, useGlobal);
    half3 ground = lerp(half3(0.561h, 0.528h, 0.462h), _XRuntimeAmbientGround.rgb, useGlobal);
    half3 upper = lerp(equator, sky, saturate(y));
    half3 lower = lerp(equator, ground, saturate(-y));
    return lerp(lower, upper, step(0.0h, y));
}

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

    inputData.positionWS = input.positionWS;

    half3 viewDirWS = GetWorldSpaceNormalizeViewDir(input.positionWS);
    // 法线已在 frag 中经 TBN 转换到世界空间后写回 input.normalWS
    inputData.normalWS = input.normalWS.xyz;

    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);
#elif defined(LIGHTMAP_ON)
    inputData.bakedGI = SAMPLE_GI(input.staticLightmapUV, input.vertexSH, inputData.normalWS);
#else
    inputData.bakedGI = SampleSH(inputData.normalWS);
#endif
    inputData.bakedGI = SampleXRuntimeAmbient(inputData.normalWS);

    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
}

#endif