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

#include "MaterialCache/MaterialCacheVirtualProducer.h"
#include "Components/PrimitiveComponent.h"
#include "Interfaces/ITargetPlatform.h"
#include "RendererInterface.h"
#include "RenderUtils.h"
#include "ScenePrivate.h"
#include "MaterialCache/MaterialCacheMeshProcessor.h"
#include "MaterialCache/MaterialCachePrimitiveData.h"
#include "MaterialCache/MaterialCacheSceneExtension.h"

FMaterialCacheVirtualProducer::FMaterialCacheVirtualProducer(FScene* Scene, FPrimitiveComponentId InPrimitiveComponentId, const FMaterialCacheTagLayout& TagLayout, const FVTProducerDescription& InProducerDesc)
: Finalizer(Scene, InPrimitiveComponentId, TagLayout, InProducerDesc)
	, Scene(Scene)
	, PrimitiveComponentId(InPrimitiveComponentId)
	, ProducerDesc(InProducerDesc)
{
	
}

bool FMaterialCacheVirtualProducer::IsPageStreamed(uint8 vLevel, uint32 vAddress) const
{
	return false;
}

FVTRequestPageResult FMaterialCacheVirtualProducer::RequestPageData(FRHICommandListBase& RHICmdList,
	const FVirtualTextureProducerHandle& ProducerHandle, uint8 LayerMask, uint8 vLevel, uint64 vAddress, EVTRequestPagePriority Priority)
{
	// Handle all requests in the owning scene's rendering cycle
	if (!Scene->GPUScene.IsRendering())
	{
		return FVTRequestPageResult(EVTRequestPageStatus::Saturated, 0u);
	}
		
#if WITH_EDITOR
	FMaterialCacheSceneExtension& Extension = Scene->GetExtension<FMaterialCacheSceneExtension>();

	// If any material is being cached, handle the request later
	// (Or if the proxy isn't ready, for any reason)
	FMaterialCachePrimitiveData* Data = Extension.GetPrimitiveData(PrimitiveComponentId);
	if (!Data || !IsMaterialCacheMaterialReady(Scene->GetShaderPlatform(), Data->Proxy))
	{
		// Note: Used Saturated as Pending may still be processed the same update
		return FVTRequestPageResult(EVTRequestPageStatus::Saturated, 0u);
	}
#endif // WITH_EDITOR
		
	// All pages are implicitly available
	return FVTRequestPageResult(EVTRequestPageStatus::Available, 0u);
}

IVirtualTextureFinalizer* FMaterialCacheVirtualProducer::ProducePageData(FRHICommandListBase& RHICmdList, ERHIFeatureLevel::Type FeatureLevel,
	EVTProducePageFlags Flags, const FVirtualTextureProducerHandle& ProducerHandle, uint8 LayerMask, uint8 vLevel, uint64 vAddress,
	uint64 RequestHandle, const FVTProduceTargetLayer* TargetLayers)
{
	FMaterialCacheTileEntry Tile;
	Tile.Address = vAddress;
	Tile.Level = vLevel;

	for (int32 LayerIndex = 0; LayerIndex < ProducerDesc.NumTextureLayers; LayerIndex++)
	{
		Tile.TargetLayers.Add(TargetLayers[LayerIndex]);
	}
		
	Finalizer.AddTile(Tile);
		
	return &Finalizer;
}