// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "RendererInterface.h"
#include "RenderGraphResources.h"

class FViewInfo;
class FRadianceCacheState;

namespace LumenRadianceCache
{
	// Must match RadianceCacheCommon.ush
	static constexpr int32 MaxClipmaps = 6;

	static constexpr int32 MinRadianceProbeResolution = 8;

	BEGIN_SHADER_PARAMETER_STRUCT(FRadianceCacheInputs, )
		SHADER_PARAMETER(float, ReprojectionRadiusScale)
		SHADER_PARAMETER(float, ClipmapWorldExtent)
		SHADER_PARAMETER(float, ClipmapDistributionBase)
		SHADER_PARAMETER(float, InvClipmapFadeSize)
		SHADER_PARAMETER(float, ProbeTMinScale)
		SHADER_PARAMETER(FIntPoint, ProbeAtlasResolutionInProbes)
		SHADER_PARAMETER(uint32, RadianceProbeClipmapResolution)
		SHADER_PARAMETER(uint32, NumRadianceProbeClipmaps)
		SHADER_PARAMETER(uint32, RadianceProbeResolution)
		SHADER_PARAMETER(uint32, FinalProbeResolution)
		SHADER_PARAMETER(uint32, FinalRadianceAtlasMaxMip)
		SHADER_PARAMETER(uint32, CalculateIrradiance)
		SHADER_PARAMETER(uint32, UseSkyVisibility)
		SHADER_PARAMETER(uint32, IrradianceProbeResolution)
		SHADER_PARAMETER(uint32, OcclusionProbeResolution)
		SHADER_PARAMETER(uint32, NumProbesToTraceBudget)
		SHADER_PARAMETER(uint32, RadianceCacheStats)
	END_SHADER_PARAMETER_STRUCT()

	FRadianceCacheInputs GetDefaultRadianceCacheInputs();

	BEGIN_SHADER_PARAMETER_STRUCT(FRadianceCacheInterpolationParameters, )
		SHADER_PARAMETER_STRUCT_INCLUDE(FRadianceCacheInputs, RadianceCacheInputs)
		SHADER_PARAMETER_RDG_TEXTURE(Texture3D<uint>, RadianceProbeIndirectionTexture)
		SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float3>, RadianceCacheFinalRadianceAtlas)
		SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float>, RadianceCacheFinalSkyVisibilityAtlas)
		SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float3>, RadianceCacheFinalIrradianceAtlas)
		SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float2>, RadianceCacheProbeOcclusionAtlas)
		SHADER_PARAMETER_RDG_TEXTURE(Texture2D<float>, RadianceCacheDepthAtlas)
		SHADER_PARAMETER_RDG_BUFFER_SRV(StructuredBuffer<float4>, ProbeWorldOffset)
		SHADER_PARAMETER_ARRAY(FVector4f, RadianceProbeSettings, [MaxClipmaps])
		SHADER_PARAMETER_ARRAY(FVector4f, ClipmapCornerTWSAndCellSize, [MaxClipmaps])
		SHADER_PARAMETER(FVector2f, InvProbeFinalRadianceAtlasResolution)
		SHADER_PARAMETER(FVector2f, InvProbeFinalIrradianceAtlasResolution)
		SHADER_PARAMETER(FVector2f, InvProbeDepthAtlasResolution)
		SHADER_PARAMETER(float, RadianceCacheOneOverCachedLightingPreExposure)
		SHADER_PARAMETER(uint32, OverrideCacheOcclusionLighting)
		SHADER_PARAMETER(uint32, ShowBlackRadianceCacheLighting)
		SHADER_PARAMETER(uint32, ProbeAtlasResolutionModuloMask)
		SHADER_PARAMETER(uint32, ProbeAtlasResolutionDivideShift)
	END_SHADER_PARAMETER_STRUCT()

	// Packed in vector to satisfy 16 byte array element alignment :
	// X=RadianceProbeClipmapTMin, Y=WorldPositionToRadianceProbeCoordScale, Z=RadianceProbeCoordToWorldPositionScale, W=[available]
	// Must match with LumenRadianceCacheInterpolation.ush
	inline void SetRadianceProbeClipmapTMin(FRadianceCacheInterpolationParameters& RadianceCacheInterpolationParameters, uint32 Index, float Value)
	{
		RadianceCacheInterpolationParameters.RadianceProbeSettings[Index].X = Value;
	}
	inline void SetClipmapCornerTWS(FRadianceCacheInterpolationParameters& RadianceCacheInterpolationParameters, uint32 Index, FVector3f Corner)
	{
		RadianceCacheInterpolationParameters.ClipmapCornerTWSAndCellSize[Index].X = Corner.X;
		RadianceCacheInterpolationParameters.ClipmapCornerTWSAndCellSize[Index].Y = Corner.Y;
		RadianceCacheInterpolationParameters.ClipmapCornerTWSAndCellSize[Index].Z = Corner.Z;
	}
	inline void SetClipmapCellSize(FRadianceCacheInterpolationParameters& RadianceCacheInterpolationParameters, uint32 Index, float CellSize)
	{
		RadianceCacheInterpolationParameters.ClipmapCornerTWSAndCellSize[Index].W = CellSize;
	}

	void GetInterpolationParameters(
		const FViewInfo& View, 
		FRDGBuilder& GraphBuilder, 
		const FRadianceCacheState& RadianceCacheState,
		const LumenRadianceCache::FRadianceCacheInputs& RadianceCacheInputs,
		FRadianceCacheInterpolationParameters& OutParameters);
};