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

#pragma once

#include "MaterialCacheABuffer.h"
#include "Engine/Texture2D.h"
#include "VirtualTexturing.h"
#include "RHIFwd.h"

class FScene;

struct FMaterialCacheTileEntry
{
	/** Destination layers */
	TArray<FVTProduceTargetLayer, TInlineAllocator<MaterialCacheMaxABuffers>> TargetLayers;

	/** Destination address (morton encoded page x/y) */
	uint64 Address = 0;

	/** Destination level */
	uint8 Level = 0;
};

class FMaterialCacheVirtualFinalizer : public IVirtualTextureFinalizer
{
public:
	FMaterialCacheVirtualFinalizer(FScene* InScene, FPrimitiveComponentId InPrimitiveComponentId, const FVTProducerDescription& InProducerDesc);
	virtual ~FMaterialCacheVirtualFinalizer() = default;

	/** Add a new tile for processing */
	void AddTile(const FMaterialCacheTileEntry& InEntry);

public: /** IVirtualTextureFinalizer */
	virtual void Finalize(FRDGBuilder& GraphBuilder) override;

protected:
	/** Render scene, lifetime tied to the parent game virtual texture */
	FScene* Scene = nullptr;
	
	/** Owning component id, lifetime tied to the parent game virtual texture */
	FPrimitiveComponentId PrimitiveComponentId;
	
	FVTProducerDescription ProducerDesc;
	EPixelFormat SourceFormat;
	EPixelFormat DestFormat;
	EPixelFormat IntermediateFormat;

private:
	struct FBucket
	{
		TArray<FMaterialCacheTileEntry> TilesToRender;
	};

	/** All pending buckets */
	TMap<IPooledRenderTarget*, FBucket> Buckets;
};