#ifndef UNIVERSAL_PARTICLES_UNLIT_FORWARD_PASS_INCLUDED
#define UNIVERSAL_PARTICLES_UNLIT_FORWARD_PASS_INCLUDED

#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Unlit.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Particles.hlsl"

void InitializeInputData(VaryingsParticle input, SurfaceData surfaceData, out InputData inputData)
{
    inputData = (InputData)0;

    inputData.positionWS = input.positionWS.xyz;

#ifdef _NORMALMAP
    half3 viewDirWS = half3(input.normalWS.w, input.tangentWS.w, input.bitangentWS.w);
    inputData.tangentToWorld = half3x3(input.tangentWS.xyz, input.bitangentWS.xyz, input.normalWS.xyz);
    inputData.normalWS = TransformTangentToWorld(surfaceData.normalTS, inputData.tangentToWorld);
#else
    half3 viewDirWS = input.viewDirWS;
    inputData.normalWS = input.normalWS;
#endif

    inputData.normalWS = NormalizeNormalPerPixel(inputData.normalWS);

#if SHADER_HINT_NICE_QUALITY
    viewDirWS = SafeNormalize(viewDirWS);
#endif

    inputData.viewDirectionWS = viewDirWS;

    inputData.fogCoord = InitializeInputDataFog(float4(input.positionWS.xyz, 1.0), input.positionWS.w);
    inputData.vertexLighting = 0;
    inputData.bakedGI = SampleSHPixel(input.vertexSH, inputData.normalWS);
    inputData.normalizedScreenSpaceUV = GetNormalizedScreenSpaceUV(input.clipPos);
    inputData.shadowMask = 1;
    inputData.shadowCoord = 0;

    #if defined(DEBUG_DISPLAY) && !defined(PARTICLES_EDITOR_META_PASS)
    inputData.vertexSH = input.vertexSH;
    #endif
}

void InitializeSurfaceData(ParticleParams particleParams, out SurfaceData surfaceData)
{
    surfaceData = (SurfaceData)0;
    half4 albedo = SampleAlbedo(TEXTURE2D_ARGS(_BaseMap, sampler_BaseMap), particleParams);
    half3 normalTS = SampleNormalTS(particleParams.uv, particleParams.blendUv, TEXTURE2D_ARGS(_BumpMap, sampler_BumpMap));

    #if defined (_DISTORTION_ON)
    albedo.rgb = Distortion(albedo, normalTS, _DistortionStrengthScaled, _DistortionBlend, particleParams.projectedPosition);
    #endif

    #if defined(_EMISSION)
    half3 emission = BlendTexture(TEXTURE2D_ARGS(_EmissionMap, sampler_EmissionMap), particleParams.uv, particleParams.blendUv).rgb * _EmissionColor.rgb;
    #else
    const half3 emission = 0;
    #endif

    surfaceData.albedo = albedo.rgb; // NOTE: Pre-multiplied and modulated in SampleAlbedo().
    surfaceData.specular = 0;
    surfaceData.normalTS = normalTS;
    surfaceData.emission = emission;
    surfaceData.metallic = 0;
    surfaceData.smoothness = 1;
    surfaceData.occlusion = 1;
    surfaceData.alpha = albedo.a;

    surfaceData.clearCoatMask       = 0;
    surfaceData.clearCoatSmoothness = 1;
}

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

VaryingsParticle vertParticleUnlit(AttributesParticle input)
{
    VaryingsParticle output = (VaryingsParticle)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);

    half fogFactor = 0.0;
#if !defined(_FOG_FRAGMENT)
    fogFactor = ComputeFogFactor(vertexInput.positionCS.z);
#endif

    // position ws is used to compute eye depth in vertFading
    output.positionWS.xyz = vertexInput.positionWS;
    output.positionWS.w = fogFactor;
    output.clipPos = vertexInput.positionCS;
    output.color = GetParticleColor(input.color);

    half3 viewDirWS = GetWorldSpaceNormalizeViewDir(vertexInput.positionWS);

#ifdef _NORMALMAP
    output.normalWS = half4(normalInput.normalWS, viewDirWS.x);
    output.tangentWS = half4(normalInput.tangentWS, viewDirWS.y);
    output.bitangentWS = half4(normalInput.bitangentWS, viewDirWS.z);
#else
    output.normalWS = half3(normalInput.normalWS);
    output.viewDirWS = viewDirWS;
#endif

#if defined(_FLIPBOOKBLENDING_ON)
#if defined(UNITY_PARTICLE_INSTANCING_ENABLED)
    GetParticleTexcoords(output.texcoord, output.texcoord2AndBlend, input.texcoords.xyxy, 0.0);
#else
    GetParticleTexcoords(output.texcoord, output.texcoord2AndBlend, input.texcoords, input.texcoordBlend);
#endif
#else
    GetParticleTexcoords(output.texcoord, input.texcoords.xy);
#endif

#if defined(_SOFTPARTICLES_ON) || defined(_FADING_ON) || defined(_DISTORTION_ON)
    output.projectedPosition = vertexInput.positionNDC;
#endif

    return output;
}

half4 fragParticleUnlit(VaryingsParticle input) : SV_Target
{
    UNITY_SETUP_INSTANCE_ID(input);
    UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);

    ParticleParams particleParams;
    InitParticleParams(input, particleParams);

    SurfaceData surfaceData;
    InitializeSurfaceData(particleParams, surfaceData);
    InputData inputData;
    InitializeInputData(input, surfaceData, inputData);
    SETUP_DEBUG_TEXTURE_DATA(inputData, input.texcoord, _BaseMap);

    half4 finalColor = UniversalFragmentUnlit(inputData, surfaceData);

    #if defined(_SCREEN_SPACE_OCCLUSION) && !defined(_SURFACE_TYPE_TRANSPARENT)
        float2 normalizedScreenSpaceUV = GetNormalizedScreenSpaceUV(input.clipPos);
        AmbientOcclusionFactor aoFactor = GetScreenSpaceAmbientOcclusion(normalizedScreenSpaceUV);
        finalColor.rgb *= aoFactor.directAmbientOcclusion;
    #endif

    finalColor.rgb = MixFog(finalColor.rgb, inputData.fogCoord);
    finalColor.a = OutputAlpha(finalColor.a, _Surface);

    return finalColor;
}

#endif // UNIVERSAL_PARTICLES_UNLIT_FORWARD_PASS_INCLUDED