UnrealEngineUWP/Engine/Source/Runtime/Landscape/Private/LandscapeEdit.cpp

// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.

/*=============================================================================
LandscapeEdit.cpp: Landscape editing
=============================================================================*/

#include "Landscape.h"
#include "LandscapeProxy.h"
#include "Materials/MaterialInstanceDynamic.h"
#include "Materials/MaterialExpressionLandscapeVisibilityMask.h"
#include "Materials/MaterialExpressionLandscapeLayerWeight.h"
#include "Materials/MaterialExpressionLandscapeLayerSample.h"
#include "Materials/MaterialExpressionLandscapeLayerBlend.h"
#include "Materials/MaterialExpressionLandscapeLayerSwitch.h"
#include "LandscapeDataAccess.h"
#include "LandscapeEdit.h"
#include "LandscapeRender.h"
#include "LandscapeRenderMobile.h"
#include "LandscapeInfo.h"
#include "LandscapeLayerInfoObject.h"
#include "LandscapeMaterialInstanceConstant.h"
#include "LandscapeHeightfieldCollisionComponent.h"
#include "LandscapeMeshCollisionComponent.h"
#include "LandscapeSplinesComponent.h"
#include "LandscapeGizmoActiveActor.h"
#include "InstancedFoliageActor.h"
#include "LevelUtils.h"
#include "MessageLog.h"
#include "MapErrors.h"
#if WITH_EDITOR
#include "RawMesh.h"
#include "ScopedTransaction.h"
#include "ImageWrapper.h"
#include "Engine/Level.h"
#include "EngineUtils.h"
#include "Engine/Engine.h"
#include "EngineGlobals.h"
#include "ShowFlags.h"
#include "ConvexVolume.h"
#endif
#include "ComponentReregisterContext.h"

DEFINE_LOG_CATEGORY(LogLandscape);

#define LOCTEXT_NAMESPACE "Landscape"

#if WITH_EDITOR

ULandscapeLayerInfoObject* ALandscapeProxy::VisibilityLayer = NULL;

void ULandscapeComponent::Init(int32 InBaseX, int32 InBaseY, int32 InComponentSizeQuads, int32 InNumSubsections, int32 InSubsectionSizeQuads)
{
	SetSectionBase(FIntPoint(InBaseX, InBaseY));
	FVector RelativeLocation = FVector(GetSectionBase() - GetLandscapeProxy()->LandscapeSectionOffset);
	SetRelativeLocation(RelativeLocation);
	ComponentSizeQuads = InComponentSizeQuads;
	NumSubsections = InNumSubsections;
	SubsectionSizeQuads = InSubsectionSizeQuads;
	check(NumSubsections * SubsectionSizeQuads == ComponentSizeQuads);
	ULandscapeInfo* Info = GetLandscapeInfo();
}

void ULandscapeComponent::UpdateCachedBounds()
{
	FLandscapeComponentDataInterface CDI(this);

	// Update local-space bounding box
	CachedLocalBox.Init();
	for (int32 y = 0; y < ComponentSizeQuads + 1; y++)
	{
		for (int32 x = 0; x < ComponentSizeQuads + 1; x++)
		{
			CachedLocalBox += CDI.GetLocalVertex(x, y);
		}
	}

	// Update collision component bounds
	ULandscapeHeightfieldCollisionComponent* HFCollisionComponent = CollisionComponent.Get();
	if (HFCollisionComponent)
	{
		HFCollisionComponent->Modify();
		HFCollisionComponent->CachedLocalBox = CachedLocalBox;
		HFCollisionComponent->UpdateComponentToWorld();
	}
}

void ULandscapeComponent::UpdateNavigationRelevance()
{
	ALandscapeProxy* Proxy = GetLandscapeProxy();
	if (CollisionComponent && Proxy)
	{
		CollisionComponent->bCanEverAffectNavigation = Proxy->bUsedForNavigation;

		UNavigationSystem::UpdateNavOctree(CollisionComponent.Get());
	}
}

ULandscapeMaterialInstanceConstant* ALandscapeProxy::GetLayerThumbnailMIC(UMaterialInterface* LandscapeMaterial, FName LayerName, UTexture2D* ThumbnailWeightmap, UTexture2D* ThumbnailHeightmap, ALandscapeProxy* Proxy)
{
	if (!LandscapeMaterial)
	{
		LandscapeMaterial = Proxy ? Proxy->GetLandscapeMaterial() : UMaterial::GetDefaultMaterial(MD_Surface);
	}

	UMaterialInstanceConstant* CombinationMaterialInstance = NULL;
	FString LayerKey = LandscapeMaterial->GetPathName() + FString::Printf(TEXT("_%s_0"), *LayerName.ToString());
	if (Proxy)
	{
		CombinationMaterialInstance = Proxy->MaterialInstanceConstantMap.FindRef(*LayerKey);
	}

	if (CombinationMaterialInstance == NULL || CombinationMaterialInstance->Parent != LandscapeMaterial || (Proxy && Proxy->GetOutermost() != CombinationMaterialInstance->GetOutermost()))
	{
		FlushRenderingCommands();
		UObject* MICOuter = GetTransientPackage();
		if (Proxy)
		{
			MICOuter = Proxy->GetOutermost();
		}
		CombinationMaterialInstance = NewObject<ULandscapeMaterialInstanceConstant>(MICOuter);
		if (Proxy)
		{
			UE_LOG(LogLandscape, Log, TEXT("Looking for key %s, making new combination %s"), *LayerKey, *CombinationMaterialInstance->GetName());
			Proxy->MaterialInstanceConstantMap.Add(*LayerKey, CombinationMaterialInstance);
		}
		CombinationMaterialInstance->SetParentEditorOnly(LandscapeMaterial);

		FStaticParameterSet StaticParameters;
		CombinationMaterialInstance->GetStaticParameterValues(StaticParameters);

		for (int32 LayerParameterIdx = 0; LayerParameterIdx < StaticParameters.TerrainLayerWeightParameters.Num(); LayerParameterIdx++)
		{
			FStaticTerrainLayerWeightParameter& LayerParameter = StaticParameters.TerrainLayerWeightParameters[LayerParameterIdx];
			if (LayerParameter.ParameterName == LayerName)
			{
				LayerParameter.WeightmapIndex = 0;
				LayerParameter.bOverride = true;
			}
			else
			{
				LayerParameter.WeightmapIndex = INDEX_NONE;
			}
		}

		CombinationMaterialInstance->UpdateStaticPermutation(StaticParameters);

		CombinationMaterialInstance->PostEditChange();
	}

	// Create the instance for this component, that will use the layer combination instance.
	ULandscapeMaterialInstanceConstant* MaterialInstance = NewObject<ULandscapeMaterialInstanceConstant>();
	MaterialInstance->SetParentEditorOnly(CombinationMaterialInstance);
	MaterialInstance->bIsLayerThumbnail = true;

	FLinearColor Mask(1.0f, 0.0f, 0.0f, 0.0f);
	MaterialInstance->SetVectorParameterValueEditorOnly(FName(*FString::Printf(TEXT("LayerMask_%s"), *LayerName.ToString())), Mask);
	MaterialInstance->SetTextureParameterValueEditorOnly(FName(TEXT("Weightmap0")), ThumbnailWeightmap);
	MaterialInstance->SetTextureParameterValueEditorOnly(FName(TEXT("Heightmap")), ThumbnailHeightmap);
	MaterialInstance->PostEditChange();

	return MaterialInstance;
}

UMaterialInstanceConstant* ULandscapeComponent::GetCombinationMaterial(bool bMobile /*= false*/)
{
	check(GIsEditor);

	ALandscapeProxy* Proxy = GetLandscapeProxy();

	const bool bComponentHasHoles = ComponentHasVisibilityPainted();
	UMaterialInterface* const LandscapeMaterial = GetLandscapeMaterial();
	UMaterialInterface* const HoleMaterial = bComponentHasHoles ? GetLandscapeHoleMaterial() : nullptr;
	UMaterialInterface* const MaterialToUse = bComponentHasHoles && HoleMaterial ? HoleMaterial : LandscapeMaterial;
	const bool bOverrideBlendMode = bComponentHasHoles && !HoleMaterial && LandscapeMaterial->GetBlendMode() == BLEND_Opaque;

	if (ensure(MaterialToUse != nullptr))
	{
		// Ensure top level UMaterial has appropriate usage flags set.
		bool bNeedsRecompile;
		UMaterial* ParentUMaterial = MaterialToUse->GetMaterial();
		if (ParentUMaterial && ParentUMaterial != UMaterial::GetDefaultMaterial(MD_Surface))
		{
			ParentUMaterial->SetMaterialUsage(bNeedsRecompile, MATUSAGE_Landscape);
			ParentUMaterial->SetMaterialUsage(bNeedsRecompile, MATUSAGE_StaticLighting);
		}

		FString LayerKey = GetLayerAllocationKey(MaterialToUse, bMobile);
		//UE_LOG(LogLandscape, Log, TEXT("Looking for key %s"), *LayerKey);

		// Find or set a matching MIC in the Landscape's map.
		UMaterialInstanceConstant* CombinationMaterialInstance = Proxy->MaterialInstanceConstantMap.FindRef(*LayerKey);
		if (CombinationMaterialInstance == nullptr || CombinationMaterialInstance->Parent != MaterialToUse || GetOutermost() != CombinationMaterialInstance->GetOutermost())
		{
			FlushRenderingCommands();

			CombinationMaterialInstance = NewObject<ULandscapeMaterialInstanceConstant>(GetOutermost());
			UE_LOG(LogLandscape, Log, TEXT("Looking for key %s, making new combination %s"), *LayerKey, *CombinationMaterialInstance->GetName());
			Proxy->MaterialInstanceConstantMap.Add(*LayerKey, CombinationMaterialInstance);
			CombinationMaterialInstance->SetParentEditorOnly(MaterialToUse);

			FStaticParameterSet StaticParameters;
			CombinationMaterialInstance->GetStaticParameterValues(StaticParameters);

			// Find weightmap mapping for each layer parameter, or disable if the layer is not used in this component.
			for (int32 LayerParameterIdx = 0; LayerParameterIdx < StaticParameters.TerrainLayerWeightParameters.Num(); LayerParameterIdx++)
			{
				FStaticTerrainLayerWeightParameter& LayerParameter = StaticParameters.TerrainLayerWeightParameters[LayerParameterIdx];
				LayerParameter.WeightmapIndex = INDEX_NONE;

				// Look through our allocations to see if we need this layer.
				// If not found, this component doesn't use the layer, and WeightmapIndex remains as INDEX_NONE.
				for (int32 AllocIdx = 0; AllocIdx < WeightmapLayerAllocations.Num(); AllocIdx++)
				{
					FWeightmapLayerAllocationInfo& Allocation = WeightmapLayerAllocations[AllocIdx];
					if (Allocation.LayerInfo != NULL)
					{
						FName ThisLayerName = (Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer) ? UMaterialExpressionLandscapeVisibilityMask::ParameterName : Allocation.LayerInfo->LayerName;
						if (ThisLayerName == LayerParameter.ParameterName)
						{
							LayerParameter.WeightmapIndex = Allocation.WeightmapTextureIndex;
							LayerParameter.bOverride = true;
							// UE_LOG(LogLandscape, Log, TEXT(" Layer %s channel %d"), *LayerParameter.ParameterName.ToString(), LayerParameter.WeightmapIndex);
							break;
						}
					}
				}
			}

			CombinationMaterialInstance->BasePropertyOverrides.bOverride_BlendMode = bOverrideBlendMode;
			if (bOverrideBlendMode)
			{
				CombinationMaterialInstance->BasePropertyOverrides.BlendMode = bComponentHasHoles ? BLEND_Masked : BLEND_Opaque;
			}

			CombinationMaterialInstance->UpdateStaticPermutation(StaticParameters);

			CombinationMaterialInstance->PostEditChange();
		}

		return CombinationMaterialInstance;
	}
	return nullptr;
}

void ULandscapeComponent::UpdateMaterialInstances()
{
	check(GIsEditor);

	// Find or set a matching MIC in the Landscape's map.
	UMaterialInstanceConstant* CombinationMaterialInstance = GetCombinationMaterial(false);

	if (CombinationMaterialInstance != NULL)
	{
		// Create the instance for this component, that will use the layer combination instance.
		if (MaterialInstance == NULL || GetOutermost() != MaterialInstance->GetOutermost())
		{
			MaterialInstance = NewObject<ULandscapeMaterialInstanceConstant>(GetOutermost());
		}

		// For undo
		MaterialInstance->SetFlags(RF_Transactional);
		MaterialInstance->Modify();

		MaterialInstance->SetParentEditorOnly(CombinationMaterialInstance);

		FLinearColor Masks[4];
		Masks[0] = FLinearColor(1.0f, 0.0f, 0.0f, 0.0f);
		Masks[1] = FLinearColor(0.0f, 1.0f, 0.0f, 0.0f);
		Masks[2] = FLinearColor(0.0f, 0.0f, 1.0f, 0.0f);
		Masks[3] = FLinearColor(0.0f, 0.0f, 0.0f, 1.0f);

		// Set the layer mask
		for (int32 AllocIdx = 0; AllocIdx < WeightmapLayerAllocations.Num(); AllocIdx++)
		{
			FWeightmapLayerAllocationInfo& Allocation = WeightmapLayerAllocations[AllocIdx];

			FName LayerName = Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer ? UMaterialExpressionLandscapeVisibilityMask::ParameterName : Allocation.LayerInfo ? Allocation.LayerInfo->LayerName : NAME_None;
			MaterialInstance->SetVectorParameterValueEditorOnly(FName(*FString::Printf(TEXT("LayerMask_%s"), *LayerName.ToString())), Masks[Allocation.WeightmapTextureChannel]);
		}

		// Set the weightmaps
		for (int32 i = 0; i < WeightmapTextures.Num(); i++)
		{
			// UE_LOG(LogLandscape, Log, TEXT("Setting Weightmap%d = %s"), i, *WeightmapTextures(i)->GetName());
			MaterialInstance->SetTextureParameterValueEditorOnly(FName(*FString::Printf(TEXT("Weightmap%d"), i)), WeightmapTextures[i]);
		}
		// Set the heightmap, if needed.

		if (HeightmapTexture)
		{
			MaterialInstance->SetTextureParameterValueEditorOnly(FName(TEXT("Heightmap")), HeightmapTexture);
		}
		MaterialInstance->PostEditChange();

		// Recreate the render state, needed to update the static drawlist which has cached the MaterialRenderProxy.
		RecreateRenderState_Concurrent();
	}
}

int32 ULandscapeComponent::GetNumMaterials() const
{
	return 1;
}

class UMaterialInterface* ULandscapeComponent::GetMaterial(int32 ElementIndex) const
{
	if (ensure(ElementIndex == 0))
	{
		return GetLandscapeMaterial();
	}
	else
	{
		return NULL;
	}
}

void ULandscapeComponent::SetMaterial(int32 ElementIndex, class UMaterialInterface* Material)
{
	if (ensure(ElementIndex == 0))
	{
		GetLandscapeProxy()->LandscapeMaterial = Material;
	}
}

bool ULandscapeComponent::ComponentIsTouchingSelectionBox(const FBox& InSelBBox, const FEngineShowFlags& ShowFlags, const bool bConsiderOnlyBSP, const bool bMustEncompassEntireComponent) const
{
	if (ShowFlags.Landscape)
	{
		return Super::ComponentIsTouchingSelectionBox(InSelBBox, ShowFlags, bConsiderOnlyBSP, bMustEncompassEntireComponent);
	}

	return false;
}

bool ULandscapeComponent::ComponentIsTouchingSelectionFrustum(const FConvexVolume& InFrustum, const FEngineShowFlags& ShowFlags, const bool bConsiderOnlyBSP, const bool bMustEncompassEntireComponent) const
{
	if (ShowFlags.Landscape)
	{
		return Super::ComponentIsTouchingSelectionFrustum(InFrustum, ShowFlags, bConsiderOnlyBSP, bMustEncompassEntireComponent);
	}

	return false;
}

void ULandscapeComponent::PostEditUndo()
{
	UpdateMaterialInstances();

	Super::PostEditUndo();

	if (EditToolRenderData)
	{
		EditToolRenderData->UpdateDebugColorMaterial();
		EditToolRenderData->UpdateSelectionMaterial(EditToolRenderData->SelectedType);
	}

	TSet<ULandscapeComponent*> Components;
	Components.Add(this);
	GetLandscapeProxy()->FlushGrassComponents(&Components);
}

void ULandscapeComponent::FixupWeightmaps()
{
	if (GIsEditor && !HasAnyFlags(RF_ClassDefaultObject))
	{
		ULandscapeInfo* Info = GetLandscapeInfo();
		ALandscapeProxy* Proxy = GetLandscapeProxy();

		if (Info)
		{
			TArray<ULandscapeLayerInfoObject*> DeletedLayers;
			bool bFixedLayerDeletion = false;

			if (Info->Layers.Num() && Cast<ALandscape>(Proxy))
			{
				// LayerName Validation check...
				for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
				{
					if (!WeightmapLayerAllocations[LayerIdx].LayerInfo
						|| (WeightmapLayerAllocations[LayerIdx].LayerInfo != ALandscapeProxy::VisibilityLayer && Info->GetLayerInfoIndex(WeightmapLayerAllocations[LayerIdx].LayerInfo) == INDEX_NONE))
					{
						if (!bFixedLayerDeletion)
						{
							FFormatNamedArguments Arguments;
							Arguments.Add(TEXT("LandscapeName"), FText::FromString(GetName()));
							FMessageLog("MapCheck").Warning()
								->AddToken(FTextToken::Create(FText::Format(LOCTEXT("MapCheck_Message_FixedUpDeletedLayerWeightmap", "{LandscapeName} : Fixed up deleted layer weightmap"), Arguments)))
								->AddToken(FMapErrorToken::Create(FMapErrors::FixedUpDeletedLayerWeightmap));
						}

						bFixedLayerDeletion = true;
						DeletedLayers.Add(WeightmapLayerAllocations[LayerIdx].LayerInfo);
					}
				}
			}

			if (bFixedLayerDeletion)
			{
				FLandscapeEditDataInterface LandscapeEdit(Info);
				for (int32 Idx = 0; Idx < DeletedLayers.Num(); ++Idx)
				{
					DeleteLayer(DeletedLayers[Idx], &LandscapeEdit);
				}
			}

			bool bFixedWeightmapTextureIndex = false;

			// Store the weightmap allocations in WeightmapUsageMap
			for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
			{
				FWeightmapLayerAllocationInfo& Allocation = WeightmapLayerAllocations[LayerIdx];

				// Fix up any problems caused by the layer deletion bug.
				if (Allocation.WeightmapTextureIndex >= WeightmapTextures.Num())
				{
					Allocation.WeightmapTextureIndex = WeightmapTextures.Num() - 1;
					if (!bFixedWeightmapTextureIndex)
					{
						FFormatNamedArguments Arguments;
						Arguments.Add(TEXT("LandscapeName"), FText::FromString(GetName()));
						FMessageLog("MapCheck").Warning()
							->AddToken(FTextToken::Create(FText::Format(LOCTEXT("MapCheck_Message_FixedUpIncorrectLayerWeightmap", "{LandscapeName} : Fixed up incorrect layer weightmap texture index"), Arguments)))
							->AddToken(FMapErrorToken::Create(FMapErrors::FixedUpIncorrectLayerWeightmap));
					}
					bFixedWeightmapTextureIndex = true;
				}

				UTexture2D* WeightmapTexture = WeightmapTextures[Allocation.WeightmapTextureIndex];
				FLandscapeWeightmapUsage& Usage = Proxy->WeightmapUsageMap.FindOrAdd(WeightmapTexture);

				// Detect a shared layer allocation, caused by a previous undo or layer deletion bugs
				if (Usage.ChannelUsage[Allocation.WeightmapTextureChannel] != NULL &&
					Usage.ChannelUsage[Allocation.WeightmapTextureChannel] != this)
				{
					FFormatNamedArguments Arguments;
					Arguments.Add(TEXT("LayerName"), FText::FromString(Allocation.GetLayerName().ToString()));
					Arguments.Add(TEXT("LandscapeName"), FText::FromString(GetName()));
					Arguments.Add(TEXT("ChannelName"), FText::FromString(Usage.ChannelUsage[Allocation.WeightmapTextureChannel]->GetName()));
					FMessageLog("MapCheck").Warning()
						->AddToken(FTextToken::Create(FText::Format(LOCTEXT("MapCheck_Message_FixedUpSharedLayerWeightmap", "Fixed up shared weightmap texture for layer {LayerName} in component '{LandscapeName}' (shares with '{ChannelName}')"), Arguments)))
						->AddToken(FMapErrorToken::Create(FMapErrors::FixedUpSharedLayerWeightmap));
					WeightmapLayerAllocations.RemoveAt(LayerIdx);
					LayerIdx--;
					continue;
				}
				else
				{
					Usage.ChannelUsage[Allocation.WeightmapTextureChannel] = this;
				}
			}

			RemoveInvalidWeightmaps();

			// Store the layer combination in the MaterialInstanceConstantMap
			if (MaterialInstance != NULL)
			{
				UMaterialInstanceConstant* CombinationMaterialInstance = Cast<UMaterialInstanceConstant>(MaterialInstance->Parent);
				if (CombinationMaterialInstance)
				{
					Proxy->MaterialInstanceConstantMap.Add(*GetLayerAllocationKey(CombinationMaterialInstance->Parent), CombinationMaterialInstance);
				}
			}
		}
	}
}

//
// LandscapeComponentAlphaInfo
//
struct FLandscapeComponentAlphaInfo
{
	int32 LayerIndex;
	TArray<uint8> AlphaValues;

	// tor
	FLandscapeComponentAlphaInfo(ULandscapeComponent* InOwner, int32 InLayerIndex)
		: LayerIndex(InLayerIndex)
	{
		AlphaValues.Empty(FMath::Square(InOwner->ComponentSizeQuads + 1));
		AlphaValues.AddZeroed(FMath::Square(InOwner->ComponentSizeQuads + 1));
	}

	bool IsLayerAllZero() const
	{
		for (int32 Index = 0; Index < AlphaValues.Num(); Index++)
		{
			if (AlphaValues[Index] != 0)
			{
				return false;
			}
		}
		return true;
	}
};


void ULandscapeComponent::UpdateCollisionHeightData(const FColor* HeightmapTextureMipData, int32 ComponentX1, int32 ComponentY1, int32 ComponentX2, int32 ComponentY2, bool bUpdateBounds, const FColor* XYOffsetmapTextureData, bool bRebuild)
{
	ULandscapeInfo* Info = GetLandscapeInfo();
	ALandscapeProxy* Proxy = GetLandscapeProxy();
	FIntPoint ComponentKey = GetSectionBase() / ComponentSizeQuads;
	ULandscapeHeightfieldCollisionComponent* CollisionComp = CollisionComponent.Get();
	ULandscapeMeshCollisionComponent* MeshCollisionComponent = Cast<ULandscapeMeshCollisionComponent>(CollisionComp);

	ULandscapeHeightfieldCollisionComponent* OldCollisionComponent = CollisionComp;

	ALandscapeProxy* CollisionProxy = NULL;
	if (CollisionComp && bRebuild)
	{
		// Remove existing component
		CollisionProxy = CollisionComp->GetLandscapeProxy();
		if (CollisionProxy)
		{
			CollisionComp->DestroyComponent();
			CollisionComp = NULL;
		}
	}

	int32 CollisionSubsectionSizeVerts = ((SubsectionSizeQuads + 1) >> CollisionMipLevel);
	int32 CollisionSubsectionSizeQuads = CollisionSubsectionSizeVerts - 1;
	int32 CollisionSizeVerts = NumSubsections*CollisionSubsectionSizeQuads + 1;

	uint16* CollisionHeightData = NULL;
	uint16* CollisionXYOffsetData = NULL;
	bool CreatedNew = false;
	bool ChangeType = false;
	TArray<uint8> DominantLayerData;
	TArray<ULandscapeLayerInfoObject*> LayerInfos;

	if (CollisionComp)
	{
		CollisionComp->Modify();
	}

	// Existing collision component is same type with collision
	if (CollisionComp && ((XYOffsetmapTexture == NULL) == (MeshCollisionComponent == NULL)))
	{
		if (bUpdateBounds)
		{
			CollisionComp->CachedLocalBox = CachedLocalBox;
			CollisionComp->UpdateComponentToWorld();
		}

		CollisionHeightData = (uint16*)CollisionComp->CollisionHeightData.Lock(LOCK_READ_WRITE);

		if (XYOffsetmapTexture && MeshCollisionComponent)
		{
			CollisionXYOffsetData = (uint16*)MeshCollisionComponent->CollisionXYOffsetData.Lock(LOCK_READ_WRITE);
		}
	}
	else
	{
		ComponentX1 = 0;
		ComponentY1 = 0;
		ComponentX2 = MAX_int32;
		ComponentY2 = MAX_int32;

		if (CollisionComp) // remove old component before changing to other type collision...
		{
			ChangeType = true;

			if (CollisionComp->DominantLayerData.GetElementCount())
			{
				DominantLayerData.AddUninitialized(FMath::Square(CollisionSizeVerts));

				const uint8* SrcDominantLayerData = (uint8*)CollisionComp->DominantLayerData.Lock(LOCK_READ_ONLY);
				FMemory::Memcpy(DominantLayerData.GetData(), SrcDominantLayerData, sizeof(uint8)*FMath::Square(CollisionSizeVerts));
				CollisionComp->DominantLayerData.Unlock();
			}

			if (CollisionComp->ComponentLayerInfos.Num())
			{
				LayerInfos = CollisionComp->ComponentLayerInfos;
			}

			if (Info)
			{
				Info->Modify();
			}
			Proxy->Modify();
			CollisionComp->DestroyComponent();
			CollisionComp = NULL;
		}

		MeshCollisionComponent = XYOffsetmapTexture ? NewObject<ULandscapeMeshCollisionComponent>(Proxy, NAME_None, RF_Transactional) : NULL;
		CollisionComp = XYOffsetmapTexture ? Cast<ULandscapeHeightfieldCollisionComponent>(MeshCollisionComponent) :
			NewObject<ULandscapeHeightfieldCollisionComponent>(Proxy, NAME_None, RF_Transactional);

		CollisionComp->SetRelativeLocation(RelativeLocation);
		CollisionComp->AttachTo(Proxy->GetRootComponent(), NAME_None);
		Proxy->CollisionComponents.Add(CollisionComp);

		CollisionComp->RenderComponent = this;
		CollisionComp->SetSectionBase(GetSectionBase());
		CollisionComp->CollisionSizeQuads = CollisionSubsectionSizeQuads * NumSubsections;
		CollisionComp->CollisionScale = (float)(ComponentSizeQuads) / (float)(CollisionComp->CollisionSizeQuads);
		CollisionComp->CachedLocalBox = CachedLocalBox;
		CreatedNew = true;

		// Reallocate raw collision data
		CollisionComp->CollisionHeightData.Lock(LOCK_READ_WRITE);
		CollisionHeightData = (uint16*)CollisionComp->CollisionHeightData.Realloc(FMath::Square(CollisionSizeVerts));
		FMemory::Memzero(CollisionHeightData, sizeof(uint16)*FMath::Square(CollisionSizeVerts));

		if (XYOffsetmapTexture && MeshCollisionComponent)
		{
			// Need XYOffsetData for Collision Component
			MeshCollisionComponent->CollisionXYOffsetData.Lock(LOCK_READ_WRITE);
			CollisionXYOffsetData = (uint16*)MeshCollisionComponent->CollisionXYOffsetData.Realloc(FMath::Square(CollisionSizeVerts) * 2);
			FMemory::Memzero(CollisionXYOffsetData, sizeof(uint16)*FMath::Square(CollisionSizeVerts) * 2);

			if (DominantLayerData.Num())
			{
				MeshCollisionComponent->DominantLayerData.Lock(LOCK_READ_WRITE);
				uint8* DestDominantLayerData = (uint8*)MeshCollisionComponent->DominantLayerData.Realloc(FMath::Square(CollisionSizeVerts));
				FMemory::Memcpy(DestDominantLayerData, DominantLayerData.GetData(), sizeof(uint8)*FMath::Square(CollisionSizeVerts));
				MeshCollisionComponent->DominantLayerData.Unlock();
			}

			if (LayerInfos.Num())
			{
				MeshCollisionComponent->ComponentLayerInfos = LayerInfos;
			}
		}
	}

	int32 HeightmapSizeU = HeightmapTexture->Source.GetSizeX();
	int32 HeightmapSizeV = HeightmapTexture->Source.GetSizeY();
	int32 MipSizeU = HeightmapSizeU >> CollisionMipLevel;
	int32 MipSizeV = HeightmapSizeV >> CollisionMipLevel;

	int32 XYMipSizeU = XYOffsetmapTexture ? XYOffsetmapTexture->Source.GetSizeX() >> CollisionMipLevel : 0;
	int32 XYMipSizeV = XYOffsetmapTexture ? XYOffsetmapTexture->Source.GetSizeY() >> CollisionMipLevel : 0;

	// Ratio to convert update region coordinate to collision mip coordinates
	float CollisionQuadRatio = (float)CollisionSubsectionSizeQuads / (float)SubsectionSizeQuads;

	// XY offset into heightmap mip data
	int32 HeightmapOffsetX = FMath::RoundToInt(HeightmapScaleBias.Z * (float)HeightmapSizeU) >> CollisionMipLevel;
	int32 HeightmapOffsetY = FMath::RoundToInt(HeightmapScaleBias.W * (float)HeightmapSizeV) >> CollisionMipLevel;

	//int32 WeightmapOffsetX = FMath::RoundToInt(WeightmapScaleBias.Z * (float)XYMipSizeU) >> CollisionMipLevel;
	//int32 WeightmapOffsetY = FMath::RoundToInt(WeightmapScaleBias.W * (float)XYMipSizeV) >> CollisionMipLevel;

	for (int32 SubsectionY = 0; SubsectionY < NumSubsections; SubsectionY++)
	{
		// Check if subsection is fully above or below the area we are interested in
		if ((ComponentY2 < SubsectionSizeQuads*SubsectionY) ||		// above
			(ComponentY1 > SubsectionSizeQuads*(SubsectionY + 1)))	// below
		{
			continue;
		}

		for (int32 SubsectionX = 0; SubsectionX < NumSubsections; SubsectionX++)
		{
			// Check if subsection is fully to the left or right of the area we are interested in
			if ((ComponentX2 < SubsectionSizeQuads*SubsectionX) ||		// left
				(ComponentX1 > SubsectionSizeQuads*(SubsectionX + 1)))	// right
			{
				continue;
			}

			// Area to update in subsection coordinates
			int32 SubX1 = ComponentX1 - SubsectionSizeQuads*SubsectionX;
			int32 SubY1 = ComponentY1 - SubsectionSizeQuads*SubsectionY;
			int32 SubX2 = ComponentX2 - SubsectionSizeQuads*SubsectionX;
			int32 SubY2 = ComponentY2 - SubsectionSizeQuads*SubsectionY;

			// Area to update in collision mip level coords
			int32 CollisionSubX1 = FMath::FloorToInt((float)SubX1 * CollisionQuadRatio);
			int32 CollisionSubY1 = FMath::FloorToInt((float)SubY1 * CollisionQuadRatio);
			int32 CollisionSubX2 = FMath::CeilToInt((float)SubX2 * CollisionQuadRatio);
			int32 CollisionSubY2 = FMath::CeilToInt((float)SubY2 * CollisionQuadRatio);

			// Clamp area to update
			int32 VertX1 = FMath::Clamp<int32>(CollisionSubX1, 0, CollisionSubsectionSizeQuads);
			int32 VertY1 = FMath::Clamp<int32>(CollisionSubY1, 0, CollisionSubsectionSizeQuads);
			int32 VertX2 = FMath::Clamp<int32>(CollisionSubX2, 0, CollisionSubsectionSizeQuads);
			int32 VertY2 = FMath::Clamp<int32>(CollisionSubY2, 0, CollisionSubsectionSizeQuads);

			for (int32 VertY = VertY1; VertY <= VertY2; VertY++)
			{
				for (int32 VertX = VertX1; VertX <= VertX2; VertX++)
				{
					{
						// X/Y of the vertex we're looking indexed into the texture data
						int32 TexX = HeightmapOffsetX + CollisionSubsectionSizeVerts * SubsectionX + VertX;
						int32 TexY = HeightmapOffsetY + CollisionSubsectionSizeVerts * SubsectionY + VertY;
						const FColor& TexData = HeightmapTextureMipData[TexX + TexY * MipSizeU];

						// this uses Quads as we don't want the duplicated vertices
						int32 CompVertX = CollisionSubsectionSizeQuads * SubsectionX + VertX;
						int32 CompVertY = CollisionSubsectionSizeQuads * SubsectionY + VertY;

						// Copy collision data
						uint16& CollisionHeight = CollisionHeightData[CompVertX + CompVertY*CollisionSizeVerts];
						uint16 NewHeight = TexData.R << 8 | TexData.G;

						CollisionHeight = NewHeight;
					}

					if (XYOffsetmapTexture && XYOffsetmapTextureData && CollisionXYOffsetData)
					{
						// X/Y of the vertex we're looking indexed into the texture data
						int32 TexX = CollisionSubsectionSizeVerts * SubsectionX + VertX;
						int32 TexY = CollisionSubsectionSizeVerts * SubsectionY + VertY;
						const FColor& TexData = XYOffsetmapTextureData[TexX + TexY * XYMipSizeU];

						// this uses Quads as we don't want the duplicated vertices
						int32 CompVertX = CollisionSubsectionSizeQuads * SubsectionX + VertX;
						int32 CompVertY = CollisionSubsectionSizeQuads * SubsectionY + VertY;

						// Copy collision data
						uint16 NewXOffset = TexData.R << 8 | TexData.G;
						uint16 NewYOffset = TexData.B << 8 | TexData.A;

						int32 XYIndex = CompVertX + CompVertY*CollisionSizeVerts;
						CollisionXYOffsetData[XYIndex * 2] = NewXOffset;
						CollisionXYOffsetData[XYIndex * 2 + 1] = NewYOffset;
					}
				}
			}
		}
	}

	CollisionComp->CollisionHeightData.Unlock();

	if (XYOffsetmapTexture && MeshCollisionComponent)
	{
		MeshCollisionComponent->CollisionXYOffsetData.Unlock();
	}

	// If we updated an existing component, we need to update the PhysX copy of the data
	if (!CreatedNew)
	{
		if (MeshCollisionComponent)
		{
			// Will be done once for XY Offset data update in FXYOffsetmapAccessor() destructor with UpdateCachedBounds()
			//MeshCollisionComponent->RecreateCollision(false);
		}
		else if (CollisionMipLevel == 0)
		{
			CollisionComp->UpdateHeightfieldRegion(ComponentX1, ComponentY1, ComponentX2, ComponentY2);
		}
		else
		{
			int32 CollisionCompX1 = FMath::FloorToInt((float)ComponentX1 * CollisionQuadRatio);
			int32 CollisionCompY1 = FMath::FloorToInt((float)ComponentY1 * CollisionQuadRatio);
			int32 CollisionCompX2 = FMath::CeilToInt((float)ComponentX2 * CollisionQuadRatio);
			int32 CollisionCompY2 = FMath::CeilToInt((float)ComponentY2 * CollisionQuadRatio);
			CollisionComp->UpdateHeightfieldRegion(CollisionCompX1, CollisionCompY1, CollisionCompX2, CollisionCompY2);
		}
	}

	{
		// set relevancy for navigation system
		ALandscapeProxy* LandscapeProxy = CollisionComp->GetLandscapeProxy();
		CollisionComp->bCanEverAffectNavigation = LandscapeProxy ? LandscapeProxy->bUsedForNavigation : false;
	}

	// Move any foliage instances if we created a new collision component.
	if (OldCollisionComponent && OldCollisionComponent != CollisionComp)
	{
		AInstancedFoliageActor::MoveInstancesToNewComponent(Proxy->GetWorld(), OldCollisionComponent, CollisionComp);
	}

	if (bRebuild && CollisionProxy)
	{
		CollisionProxy->RegisterAllComponents();
	}

	// Set new collision component to pointer
	CollisionComponent = CollisionComp;

	if (ChangeType || CreatedNew)
	{
		Proxy->RegisterAllComponents();
	}
}


void ULandscapeComponent::UpdateCollisionLayerData(TArray<FColor*>& WeightmapTextureMipData, int32 ComponentX1, int32 ComponentY1, int32 ComponentX2, int32 ComponentY2)
{
	ULandscapeInfo* Info = GetLandscapeInfo();
	ALandscapeProxy* Proxy = GetLandscapeProxy();
	FIntPoint ComponentKey = GetSectionBase() / ComponentSizeQuads;

	if (CollisionComponent)
	{
		CollisionComponent->Modify();

		TArray<ULandscapeLayerInfoObject*> CandidateLayers;
		TArray<uint8*> CandidateDataPtrs;

		// Channel remapping
		int32 ChannelOffsets[4] = { (int32)STRUCT_OFFSET(FColor, R), (int32)STRUCT_OFFSET(FColor, G), (int32)STRUCT_OFFSET(FColor, B), (int32)STRUCT_OFFSET(FColor, A) };

		bool bExistingLayerMismatch = false;
		int32 DataLayerIdx = INDEX_NONE;

		// Find the layers we're interested in
		for (int32 AllocIdx = 0; AllocIdx < WeightmapLayerAllocations.Num(); AllocIdx++)
		{
			FWeightmapLayerAllocationInfo& AllocInfo = WeightmapLayerAllocations[AllocIdx];
			ULandscapeLayerInfoObject* LayerInfo = AllocInfo.LayerInfo;
			if (LayerInfo == ALandscapeProxy::VisibilityLayer || LayerInfo != nullptr)
			{
				int32 Idx = CandidateLayers.Add(LayerInfo);
				CandidateDataPtrs.Add(((uint8*)WeightmapTextureMipData[AllocInfo.WeightmapTextureIndex]) + ChannelOffsets[AllocInfo.WeightmapTextureChannel]);

				// Check if we still match the collision component.
				if (!CollisionComponent->ComponentLayerInfos.IsValidIndex(Idx) || CollisionComponent->ComponentLayerInfos[Idx] != LayerInfo)
				{
					bExistingLayerMismatch = true;
				}

				if (LayerInfo == ALandscapeProxy::VisibilityLayer)
				{
					DataLayerIdx = Idx;
					bExistingLayerMismatch = true; // always rebuild whole component for hole
				}
			}
		}

		if (CandidateLayers.Num() == 0)
		{
			// No layers, so don't update any weights
			CollisionComponent->DominantLayerData.RemoveBulkData();
			CollisionComponent->ComponentLayerInfos.Empty();
		}
		else
		{
			int32 CollisionSubsectionSizeVerts = ((SubsectionSizeQuads + 1) >> CollisionMipLevel);
			int32 CollisionSubsectionSizeQuads = CollisionSubsectionSizeVerts - 1;
			int32 CollisionSizeVerts = NumSubsections*CollisionSubsectionSizeQuads + 1;
			uint8* DominantLayerData = NULL;

			// If there's no existing data, or the layer allocations have changed, we need to update the data for the whole component.
			if (bExistingLayerMismatch || CollisionComponent->DominantLayerData.GetElementCount() == 0)
			{
				ComponentX1 = 0;
				ComponentY1 = 0;
				ComponentX2 = MAX_int32;
				ComponentY2 = MAX_int32;

				CollisionComponent->DominantLayerData.Lock(LOCK_READ_WRITE);
				DominantLayerData = (uint8*)CollisionComponent->DominantLayerData.Realloc(FMath::Square(CollisionSizeVerts));
				FMemory::Memzero(DominantLayerData, FMath::Square(CollisionSizeVerts));

				CollisionComponent->ComponentLayerInfos = CandidateLayers;
			}
			else
			{
				DominantLayerData = (uint8*)CollisionComponent->DominantLayerData.Lock(LOCK_READ_WRITE);
			}

			int32 MipSizeU = (WeightmapTextures[0]->Source.GetSizeX()) >> CollisionMipLevel;

			// Ratio to convert update region coordinate to collision mip coordinates
			float CollisionQuadRatio = (float)CollisionSubsectionSizeQuads / (float)SubsectionSizeQuads;

			for (int32 SubsectionY = 0; SubsectionY < NumSubsections; SubsectionY++)
			{
				// Check if subsection is fully above or below the area we are interested in
				if ((ComponentY2 < SubsectionSizeQuads*SubsectionY) ||		// above
					(ComponentY1 > SubsectionSizeQuads*(SubsectionY + 1)))	// below
				{
					continue;
				}

				for (int32 SubsectionX = 0; SubsectionX < NumSubsections; SubsectionX++)
				{
					// Check if subsection is fully to the left or right of the area we are interested in
					if ((ComponentX2 < SubsectionSizeQuads*SubsectionX) ||		// left
						(ComponentX1 > SubsectionSizeQuads*(SubsectionX + 1)))	// right
					{
						continue;
					}

					// Area to update in subsection coordinates
					int32 SubX1 = ComponentX1 - SubsectionSizeQuads*SubsectionX;
					int32 SubY1 = ComponentY1 - SubsectionSizeQuads*SubsectionY;
					int32 SubX2 = ComponentX2 - SubsectionSizeQuads*SubsectionX;
					int32 SubY2 = ComponentY2 - SubsectionSizeQuads*SubsectionY;

					// Area to update in collision mip level coords
					int32 CollisionSubX1 = FMath::FloorToInt((float)SubX1 * CollisionQuadRatio);
					int32 CollisionSubY1 = FMath::FloorToInt((float)SubY1 * CollisionQuadRatio);
					int32 CollisionSubX2 = FMath::CeilToInt((float)SubX2 * CollisionQuadRatio);
					int32 CollisionSubY2 = FMath::CeilToInt((float)SubY2 * CollisionQuadRatio);

					// Clamp area to update
					int32 VertX1 = FMath::Clamp<int32>(CollisionSubX1, 0, CollisionSubsectionSizeQuads);
					int32 VertY1 = FMath::Clamp<int32>(CollisionSubY1, 0, CollisionSubsectionSizeQuads);
					int32 VertX2 = FMath::Clamp<int32>(CollisionSubX2, 0, CollisionSubsectionSizeQuads);
					int32 VertY2 = FMath::Clamp<int32>(CollisionSubY2, 0, CollisionSubsectionSizeQuads);

					for (int32 VertY = VertY1; VertY <= VertY2; VertY++)
					{
						for (int32 VertX = VertX1; VertX <= VertX2; VertX++)
						{
							// X/Y of the vertex we're looking indexed into the texture data
							int32 TexX = CollisionSubsectionSizeVerts * SubsectionX + VertX;
							int32 TexY = CollisionSubsectionSizeVerts * SubsectionY + VertY;
							int32 DataOffset = (TexX + TexY * MipSizeU) * sizeof(FColor);

							uint8 DominantLayer = 255; // 255 as invalid value
							int32 DominantWeight = 0;
							for (int32 LayerIdx = 0; LayerIdx < CandidateDataPtrs.Num(); LayerIdx++)
							{
								const uint8 LayerWeight = CandidateDataPtrs[LayerIdx][DataOffset];

								if (LayerIdx == DataLayerIdx) // Override value for hole
								{
									if (LayerWeight > 170) // 255 * 0.66...
									{
										DominantLayer = LayerIdx;
										DominantWeight = INT_MAX;
									}
								}
								else if (LayerWeight > DominantWeight)
								{
									DominantLayer = LayerIdx;
									DominantWeight = LayerWeight;
								}
							}

							// this uses Quads as we don't want the duplicated vertices
							int32 CompVertX = CollisionSubsectionSizeQuads * SubsectionX + VertX;
							int32 CompVertY = CollisionSubsectionSizeQuads * SubsectionY + VertY;

							// Set collision data
							DominantLayerData[CompVertX + CompVertY*CollisionSizeVerts] = DominantLayer;
						}
					}
				}
			}
			CollisionComponent->DominantLayerData.Unlock();
		}

		// We do not force an update of the physics data here. We don't need the layer information in the editor and it
		// causes problems if we update it multiple times in a single frame.
	}
}


void ULandscapeComponent::UpdateCollisionLayerData()
{
	// Generate the dominant layer data
	TArray<FColor*> WeightmapTextureMipData;
	TArray<TArray<uint8> > CachedWeightmapTextureMipData;

	WeightmapTextureMipData.Empty(WeightmapTextures.Num());
	CachedWeightmapTextureMipData.Empty(WeightmapTextures.Num());
	for (int32 Idx = 0; Idx < WeightmapTextures.Num(); Idx++)
	{
		TArray<uint8>* MipData = new(CachedWeightmapTextureMipData)TArray<uint8>();
		WeightmapTextures[Idx]->Source.GetMipData(*MipData, CollisionMipLevel);
		WeightmapTextureMipData.Add((FColor*)MipData->GetData());
	}

	UpdateCollisionLayerData(WeightmapTextureMipData);
}




void ULandscapeComponent::GenerateHeightmapMips(TArray<FColor*>& HeightmapTextureMipData, int32 ComponentX1/*=0*/, int32 ComponentY1/*=0*/, int32 ComponentX2/*=MAX_int32*/, int32 ComponentY2/*=MAX_int32*/, struct FLandscapeTextureDataInfo* TextureDataInfo/*=NULL*/)
{
	bool EndX = false;
	bool EndY = false;

	if (ComponentX1 == MAX_int32)
	{
		EndX = true;
		ComponentX1 = 0;
	}

	if (ComponentY1 == MAX_int32)
	{
		EndY = true;
		ComponentY1 = 0;
	}

	if (ComponentX2 == MAX_int32)
	{
		ComponentX2 = ComponentSizeQuads;
	}
	if (ComponentY2 == MAX_int32)
	{
		ComponentY2 = ComponentSizeQuads;
	}

	int32 HeightmapSizeU = HeightmapTexture->Source.GetSizeX();
	int32 HeightmapSizeV = HeightmapTexture->Source.GetSizeY();

	int32 HeightmapOffsetX = FMath::RoundToInt(HeightmapScaleBias.Z * (float)HeightmapSizeU);
	int32 HeightmapOffsetY = FMath::RoundToInt(HeightmapScaleBias.W * (float)HeightmapSizeV);

	for (int32 SubsectionY = 0; SubsectionY < NumSubsections; SubsectionY++)
	{
		// Check if subsection is fully above or below the area we are interested in
		if ((ComponentY2 < SubsectionSizeQuads*SubsectionY) ||		// above
			(ComponentY1 > SubsectionSizeQuads*(SubsectionY + 1)))	// below
		{
			continue;
		}

		for (int32 SubsectionX = 0; SubsectionX < NumSubsections; SubsectionX++)
		{
			// Check if subsection is fully to the left or right of the area we are interested in
			if ((ComponentX2 < SubsectionSizeQuads*SubsectionX) ||		// left
				(ComponentX1 > SubsectionSizeQuads*(SubsectionX + 1)))	// right
			{
				continue;
			}

			// Area to update in previous mip level coords
			int32 PrevMipSubX1 = ComponentX1 - SubsectionSizeQuads*SubsectionX;
			int32 PrevMipSubY1 = ComponentY1 - SubsectionSizeQuads*SubsectionY;
			int32 PrevMipSubX2 = ComponentX2 - SubsectionSizeQuads*SubsectionX;
			int32 PrevMipSubY2 = ComponentY2 - SubsectionSizeQuads*SubsectionY;

			int32 PrevMipSubsectionSizeQuads = SubsectionSizeQuads;
			float InvPrevMipSubsectionSizeQuads = 1.0f / (float)SubsectionSizeQuads;

			int32 PrevMipSizeU = HeightmapSizeU;
			int32 PrevMipSizeV = HeightmapSizeV;

			int32 PrevMipHeightmapOffsetX = HeightmapOffsetX;
			int32 PrevMipHeightmapOffsetY = HeightmapOffsetY;

			for (int32 Mip = 1; Mip < HeightmapTextureMipData.Num(); Mip++)
			{
				int32 MipSizeU = HeightmapSizeU >> Mip;
				int32 MipSizeV = HeightmapSizeV >> Mip;

				int32 MipSubsectionSizeQuads = ((SubsectionSizeQuads + 1) >> Mip) - 1;
				float InvMipSubsectionSizeQuads = 1.0f / (float)MipSubsectionSizeQuads;

				int32 MipHeightmapOffsetX = HeightmapOffsetX >> Mip;
				int32 MipHeightmapOffsetY = HeightmapOffsetY >> Mip;

				// Area to update in current mip level coords
				int32 MipSubX1 = FMath::FloorToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubX1 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubY1 = FMath::FloorToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubY1 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubX2 = FMath::CeilToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubX2 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubY2 = FMath::CeilToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubY2 * InvPrevMipSubsectionSizeQuads);

				// Clamp area to update
				int32 VertX1 = FMath::Clamp<int32>(MipSubX1, 0, MipSubsectionSizeQuads);
				int32 VertY1 = FMath::Clamp<int32>(MipSubY1, 0, MipSubsectionSizeQuads);
				int32 VertX2 = FMath::Clamp<int32>(MipSubX2, 0, MipSubsectionSizeQuads);
				int32 VertY2 = FMath::Clamp<int32>(MipSubY2, 0, MipSubsectionSizeQuads);

				for (int32 VertY = VertY1; VertY <= VertY2; VertY++)
				{
					for (int32 VertX = VertX1; VertX <= VertX2; VertX++)
					{
						// Convert VertX/Y into previous mip's coords
						float PrevMipVertX = (float)PrevMipSubsectionSizeQuads * (float)VertX * InvMipSubsectionSizeQuads;
						float PrevMipVertY = (float)PrevMipSubsectionSizeQuads * (float)VertY * InvMipSubsectionSizeQuads;

#if 0
						// Validate that the vertex we skip wouldn't use the updated data in the parent mip.
						// Note this validation is doesn't do anything unless you change the VertY/VertX loops 
						// above to process all verts from 0 .. MipSubsectionSizeQuads.
						if (VertX < VertX1 || VertX > VertX2)
						{
							check(FMath::CeilToInt(PrevMipVertX) < PrevMipSubX1 || FMath::FloorToInt(PrevMipVertX) > PrevMipSubX2);
							continue;
						}

						if (VertY < VertY1 || VertY > VertY2)
						{
							check(FMath::CeilToInt(PrevMipVertY) < PrevMipSubY1 || FMath::FloorToInt(PrevMipVertY) > PrevMipSubY2);
							continue;
						}
#endif

						// X/Y of the vertex we're looking indexed into the texture data
						int32 TexX = (MipHeightmapOffsetX)+(MipSubsectionSizeQuads + 1) * SubsectionX + VertX;
						int32 TexY = (MipHeightmapOffsetY)+(MipSubsectionSizeQuads + 1) * SubsectionY + VertY;

						float fPrevMipTexX = (float)(PrevMipHeightmapOffsetX)+(float)((PrevMipSubsectionSizeQuads + 1) * SubsectionX) + PrevMipVertX;
						float fPrevMipTexY = (float)(PrevMipHeightmapOffsetY)+(float)((PrevMipSubsectionSizeQuads + 1) * SubsectionY) + PrevMipVertY;

						int32 PrevMipTexX = FMath::FloorToInt(fPrevMipTexX);
						float fPrevMipTexFracX = FMath::Fractional(fPrevMipTexX);
						int32 PrevMipTexY = FMath::FloorToInt(fPrevMipTexY);
						float fPrevMipTexFracY = FMath::Fractional(fPrevMipTexY);

						checkSlow(TexX >= 0 && TexX < MipSizeU);
						checkSlow(TexY >= 0 && TexY < MipSizeV);
						checkSlow(PrevMipTexX >= 0 && PrevMipTexX < PrevMipSizeU);
						checkSlow(PrevMipTexY >= 0 && PrevMipTexY < PrevMipSizeV);

						int32 PrevMipTexX1 = FMath::Min<int32>(PrevMipTexX + 1, PrevMipSizeU - 1);
						int32 PrevMipTexY1 = FMath::Min<int32>(PrevMipTexY + 1, PrevMipSizeV - 1);

						// Padding for missing data for MIP 0
						if (Mip == 1)
						{
							if (EndX && SubsectionX == NumSubsections - 1 && VertX == VertX2)
							{
								for (int32 PaddingIdx = PrevMipTexX + PrevMipTexY * PrevMipSizeU; PaddingIdx + 1 < PrevMipTexY1 * PrevMipSizeU; ++PaddingIdx)
								{
									HeightmapTextureMipData[Mip - 1][PaddingIdx + 1] = HeightmapTextureMipData[Mip - 1][PaddingIdx];
								}
							}

							if (EndY && SubsectionX == NumSubsections - 1 && SubsectionY == NumSubsections - 1 && VertY == VertY2 && VertX == VertX2)
							{
								for (int32 PaddingYIdx = PrevMipTexY; PaddingYIdx + 1 < PrevMipSizeV; ++PaddingYIdx)
								{
									for (int32 PaddingXIdx = 0; PaddingXIdx < PrevMipSizeU; ++PaddingXIdx)
									{
										HeightmapTextureMipData[Mip - 1][PaddingXIdx + (PaddingYIdx + 1) * PrevMipSizeU] = HeightmapTextureMipData[Mip - 1][PaddingXIdx + PaddingYIdx * PrevMipSizeU];
									}
								}
							}
						}

						FColor* TexData = &(HeightmapTextureMipData[Mip])[TexX + TexY * MipSizeU];
						FColor *PreMipTexData00 = &(HeightmapTextureMipData[Mip - 1])[PrevMipTexX + PrevMipTexY * PrevMipSizeU];
						FColor *PreMipTexData01 = &(HeightmapTextureMipData[Mip - 1])[PrevMipTexX + PrevMipTexY1 * PrevMipSizeU];
						FColor *PreMipTexData10 = &(HeightmapTextureMipData[Mip - 1])[PrevMipTexX1 + PrevMipTexY * PrevMipSizeU];
						FColor *PreMipTexData11 = &(HeightmapTextureMipData[Mip - 1])[PrevMipTexX1 + PrevMipTexY1 * PrevMipSizeU];

						// Lerp height values
						uint16 PrevMipHeightValue00 = PreMipTexData00->R << 8 | PreMipTexData00->G;
						uint16 PrevMipHeightValue01 = PreMipTexData01->R << 8 | PreMipTexData01->G;
						uint16 PrevMipHeightValue10 = PreMipTexData10->R << 8 | PreMipTexData10->G;
						uint16 PrevMipHeightValue11 = PreMipTexData11->R << 8 | PreMipTexData11->G;
						uint16 HeightValue = FMath::RoundToInt(
							FMath::Lerp(
							FMath::Lerp((float)PrevMipHeightValue00, (float)PrevMipHeightValue10, fPrevMipTexFracX),
							FMath::Lerp((float)PrevMipHeightValue01, (float)PrevMipHeightValue11, fPrevMipTexFracX),
							fPrevMipTexFracY));

						TexData->R = HeightValue >> 8;
						TexData->G = HeightValue & 255;

						// Lerp tangents
						TexData->B = FMath::RoundToInt(
							FMath::Lerp(
							FMath::Lerp((float)PreMipTexData00->B, (float)PreMipTexData10->B, fPrevMipTexFracX),
							FMath::Lerp((float)PreMipTexData01->B, (float)PreMipTexData11->B, fPrevMipTexFracX),
							fPrevMipTexFracY));

						TexData->A = FMath::RoundToInt(
							FMath::Lerp(
							FMath::Lerp((float)PreMipTexData00->A, (float)PreMipTexData10->A, fPrevMipTexFracX),
							FMath::Lerp((float)PreMipTexData01->A, (float)PreMipTexData11->A, fPrevMipTexFracX),
							fPrevMipTexFracY));

						// Padding for missing data
						if (EndX && SubsectionX == NumSubsections - 1 && VertX == VertX2)
						{
							for (int32 PaddingIdx = TexX + TexY * MipSizeU; PaddingIdx + 1 < (TexY + 1) * MipSizeU; ++PaddingIdx)
							{
								HeightmapTextureMipData[Mip][PaddingIdx + 1] = HeightmapTextureMipData[Mip][PaddingIdx];
							}
						}

						if (EndY && SubsectionX == NumSubsections - 1 && SubsectionY == NumSubsections - 1 && VertY == VertY2 && VertX == VertX2)
						{
							for (int32 PaddingYIdx = TexY; PaddingYIdx + 1 < MipSizeV; ++PaddingYIdx)
							{
								for (int32 PaddingXIdx = 0; PaddingXIdx < MipSizeU; ++PaddingXIdx)
								{
									HeightmapTextureMipData[Mip][PaddingXIdx + (PaddingYIdx + 1) * MipSizeU] = HeightmapTextureMipData[Mip][PaddingXIdx + PaddingYIdx * MipSizeU];
								}
							}
						}

					}
				}

				// Record the areas we updated
				if (TextureDataInfo)
				{
					int32 TexX1 = (MipHeightmapOffsetX)+(MipSubsectionSizeQuads + 1) * SubsectionX + VertX1;
					int32 TexY1 = (MipHeightmapOffsetY)+(MipSubsectionSizeQuads + 1) * SubsectionY + VertY1;
					int32 TexX2 = (MipHeightmapOffsetX)+(MipSubsectionSizeQuads + 1) * SubsectionX + VertX2;
					int32 TexY2 = (MipHeightmapOffsetY)+(MipSubsectionSizeQuads + 1) * SubsectionY + VertY2;
					TextureDataInfo->AddMipUpdateRegion(Mip, TexX1, TexY1, TexX2, TexY2);
				}

				// Copy current mip values to prev as we move to the next mip.
				PrevMipSubsectionSizeQuads = MipSubsectionSizeQuads;
				InvPrevMipSubsectionSizeQuads = InvMipSubsectionSizeQuads;

				PrevMipSizeU = MipSizeU;
				PrevMipSizeV = MipSizeV;

				PrevMipHeightmapOffsetX = MipHeightmapOffsetX;
				PrevMipHeightmapOffsetY = MipHeightmapOffsetY;

				// Use this mip's area as we move to the next mip
				PrevMipSubX1 = MipSubX1;
				PrevMipSubY1 = MipSubY1;
				PrevMipSubX2 = MipSubX2;
				PrevMipSubY2 = MipSubY2;
			}
		}
	}
}

void ULandscapeComponent::CreateEmptyTextureMips(UTexture2D* Texture, bool bClear /*= false*/)
{
	ETextureSourceFormat WeightmapFormat = Texture->Source.GetFormat();
	int32 WeightmapSizeU = Texture->Source.GetSizeX();
	int32 WeightmapSizeV = Texture->Source.GetSizeY();

	if (bClear)
	{
		Texture->Source.Init2DWithMipChain(WeightmapSizeU, WeightmapSizeV, WeightmapFormat);
		int32 NumMips = Texture->Source.GetNumMips();
		for (int32 MipIndex = 0; MipIndex < NumMips; ++MipIndex)
		{
			uint8* MipData = Texture->Source.LockMip(MipIndex);
			FMemory::Memzero(MipData, Texture->Source.CalcMipSize(MipIndex));
			Texture->Source.UnlockMip(MipIndex);
		}
	}
	else
	{
		TArray<uint8> TopMipData;
		Texture->Source.GetMipData(TopMipData, 0);
		Texture->Source.Init2DWithMipChain(WeightmapSizeU, WeightmapSizeV, WeightmapFormat);
		int32 NumMips = Texture->Source.GetNumMips();
		uint8* MipData = Texture->Source.LockMip(0);
		FMemory::Memcpy(MipData, TopMipData.GetData(), TopMipData.Num());
		Texture->Source.UnlockMip(0);
	}
}

template<typename DataType>
void ULandscapeComponent::GenerateMipsTempl(int32 InNumSubsections, int32 InSubsectionSizeQuads, UTexture2D* Texture, DataType* BaseMipData)
{
	// Stores pointers to the locked mip data
	TArray<DataType*> MipData;
	MipData.Add(BaseMipData);
	for (int32 MipIndex = 1; MipIndex < Texture->Source.GetNumMips(); ++MipIndex)
	{
		MipData.Add((DataType*)Texture->Source.LockMip(MipIndex));
	}

	// Update the newly created mips
	UpdateMipsTempl<DataType>(InNumSubsections, InSubsectionSizeQuads, Texture, MipData);

	// Unlock all the new mips, but not the base mip's data
	for (int32 i = 1; i < MipData.Num(); i++)
	{
		Texture->Source.UnlockMip(i);
	}
}

void ULandscapeComponent::GenerateWeightmapMips(int32 InNumSubsections, int32 InSubsectionSizeQuads, UTexture2D* WeightmapTexture, FColor* BaseMipData)
{
	GenerateMipsTempl<FColor>(InNumSubsections, InSubsectionSizeQuads, WeightmapTexture, BaseMipData);
}

namespace
{
	template<typename DataType>
	void BiLerpTextureData(DataType* Output, const DataType* Data00, const DataType* Data10, const DataType* Data01, const DataType* Data11, float FracX, float FracY)
	{
		*Output = FMath::RoundToInt(
			FMath::Lerp(
			FMath::Lerp((float)*Data00, (float)*Data10, FracX),
			FMath::Lerp((float)*Data01, (float)*Data11, FracX),
			FracY));
	}

	template<>
	void BiLerpTextureData(FColor* Output, const FColor* Data00, const FColor* Data10, const FColor* Data01, const FColor* Data11, float FracX, float FracY)
	{
		Output->R = FMath::RoundToInt(
			FMath::Lerp(
			FMath::Lerp((float)Data00->R, (float)Data10->R, FracX),
			FMath::Lerp((float)Data01->R, (float)Data11->R, FracX),
			FracY));
		Output->G = FMath::RoundToInt(
			FMath::Lerp(
			FMath::Lerp((float)Data00->G, (float)Data10->G, FracX),
			FMath::Lerp((float)Data01->G, (float)Data11->G, FracX),
			FracY));
		Output->B = FMath::RoundToInt(
			FMath::Lerp(
			FMath::Lerp((float)Data00->B, (float)Data10->B, FracX),
			FMath::Lerp((float)Data01->B, (float)Data11->B, FracX),
			FracY));
		Output->A = FMath::RoundToInt(
			FMath::Lerp(
			FMath::Lerp((float)Data00->A, (float)Data10->A, FracX),
			FMath::Lerp((float)Data01->A, (float)Data11->A, FracX),
			FracY));
	}

	template<typename DataType>
	void AverageTexData(DataType* Output, const DataType* Data00, const DataType* Data10, const DataType* Data01, const DataType* Data11)
	{
		*Output = (((int32)(*Data00) + (int32)(*Data10) + (int32)(*Data01) + (int32)(*Data11)) >> 2);
	}

	template<>
	void AverageTexData(FColor* Output, const FColor* Data00, const FColor* Data10, const FColor* Data01, const FColor* Data11)
	{
		Output->R = (((int32)Data00->R + (int32)Data10->R + (int32)Data01->R + (int32)Data11->R) >> 2);
		Output->G = (((int32)Data00->G + (int32)Data10->G + (int32)Data01->G + (int32)Data11->G) >> 2);
		Output->B = (((int32)Data00->B + (int32)Data10->B + (int32)Data01->B + (int32)Data11->B) >> 2);
		Output->A = (((int32)Data00->A + (int32)Data10->A + (int32)Data01->A + (int32)Data11->A) >> 2);
	}

};

template<typename DataType>
void ULandscapeComponent::UpdateMipsTempl(int32 InNumSubsections, int32 InSubsectionSizeQuads, UTexture2D* Texture, TArray<DataType*>& TextureMipData, int32 ComponentX1/*=0*/, int32 ComponentY1/*=0*/, int32 ComponentX2/*=MAX_int32*/, int32 ComponentY2/*=MAX_int32*/, struct FLandscapeTextureDataInfo* TextureDataInfo/*=NULL*/)
{
	int32 WeightmapSizeU = Texture->Source.GetSizeX();
	int32 WeightmapSizeV = Texture->Source.GetSizeY();

	// Find the maximum mip where each texel's data comes from just one subsection.
	int32 MaxWholeSubsectionMip = FMath::FloorLog2(InSubsectionSizeQuads + 1) - 1;

	// Update the mip where each texel's data comes from just one subsection.
	for (int32 SubsectionY = 0; SubsectionY < InNumSubsections; SubsectionY++)
	{
		// Check if subsection is fully above or below the area we are interested in
		if ((ComponentY2 < InSubsectionSizeQuads*SubsectionY) ||	// above
			(ComponentY1 > InSubsectionSizeQuads*(SubsectionY + 1)))	// below
		{
			continue;
		}

		for (int32 SubsectionX = 0; SubsectionX < InNumSubsections; SubsectionX++)
		{
			// Check if subsection is fully to the left or right of the area we are interested in
			if ((ComponentX2 < InSubsectionSizeQuads*SubsectionX) ||	// left
				(ComponentX1 > InSubsectionSizeQuads*(SubsectionX + 1)))	// right
			{
				continue;
			}

			// Area to update in previous mip level coords
			int32 PrevMipSubX1 = ComponentX1 - InSubsectionSizeQuads*SubsectionX;
			int32 PrevMipSubY1 = ComponentY1 - InSubsectionSizeQuads*SubsectionY;
			int32 PrevMipSubX2 = ComponentX2 - InSubsectionSizeQuads*SubsectionX;
			int32 PrevMipSubY2 = ComponentY2 - InSubsectionSizeQuads*SubsectionY;

			int32 PrevMipSubsectionSizeQuads = InSubsectionSizeQuads;
			float InvPrevMipSubsectionSizeQuads = 1.0f / (float)InSubsectionSizeQuads;

			int32 PrevMipSizeU = WeightmapSizeU;
			int32 PrevMipSizeV = WeightmapSizeV;

			for (int32 Mip = 1; Mip <= MaxWholeSubsectionMip; Mip++)
			{
				int32 MipSizeU = WeightmapSizeU >> Mip;
				int32 MipSizeV = WeightmapSizeV >> Mip;

				int32 MipSubsectionSizeQuads = ((InSubsectionSizeQuads + 1) >> Mip) - 1;
				float InvMipSubsectionSizeQuads = 1.0f / (float)MipSubsectionSizeQuads;

				// Area to update in current mip level coords
				int32 MipSubX1 = FMath::FloorToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubX1 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubY1 = FMath::FloorToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubY1 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubX2 = FMath::CeilToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubX2 * InvPrevMipSubsectionSizeQuads);
				int32 MipSubY2 = FMath::CeilToInt((float)MipSubsectionSizeQuads * (float)PrevMipSubY2 * InvPrevMipSubsectionSizeQuads);

				// Clamp area to update
				int32 VertX1 = FMath::Clamp<int32>(MipSubX1, 0, MipSubsectionSizeQuads);
				int32 VertY1 = FMath::Clamp<int32>(MipSubY1, 0, MipSubsectionSizeQuads);
				int32 VertX2 = FMath::Clamp<int32>(MipSubX2, 0, MipSubsectionSizeQuads);
				int32 VertY2 = FMath::Clamp<int32>(MipSubY2, 0, MipSubsectionSizeQuads);

				for (int32 VertY = VertY1; VertY <= VertY2; VertY++)
				{
					for (int32 VertX = VertX1; VertX <= VertX2; VertX++)
					{
						// Convert VertX/Y into previous mip's coords
						float PrevMipVertX = (float)PrevMipSubsectionSizeQuads * (float)VertX * InvMipSubsectionSizeQuads;
						float PrevMipVertY = (float)PrevMipSubsectionSizeQuads * (float)VertY * InvMipSubsectionSizeQuads;

						// X/Y of the vertex we're looking indexed into the texture data
						int32 TexX = (MipSubsectionSizeQuads + 1) * SubsectionX + VertX;
						int32 TexY = (MipSubsectionSizeQuads + 1) * SubsectionY + VertY;

						float fPrevMipTexX = (float)((PrevMipSubsectionSizeQuads + 1) * SubsectionX) + PrevMipVertX;
						float fPrevMipTexY = (float)((PrevMipSubsectionSizeQuads + 1) * SubsectionY) + PrevMipVertY;

						int32 PrevMipTexX = FMath::FloorToInt(fPrevMipTexX);
						float fPrevMipTexFracX = FMath::Fractional(fPrevMipTexX);
						int32 PrevMipTexY = FMath::FloorToInt(fPrevMipTexY);
						float fPrevMipTexFracY = FMath::Fractional(fPrevMipTexY);

						check(TexX >= 0 && TexX < MipSizeU);
						check(TexY >= 0 && TexY < MipSizeV);
						check(PrevMipTexX >= 0 && PrevMipTexX < PrevMipSizeU);
						check(PrevMipTexY >= 0 && PrevMipTexY < PrevMipSizeV);

						int32 PrevMipTexX1 = FMath::Min<int32>(PrevMipTexX + 1, PrevMipSizeU - 1);
						int32 PrevMipTexY1 = FMath::Min<int32>(PrevMipTexY + 1, PrevMipSizeV - 1);

						DataType* TexData = &(TextureMipData[Mip])[TexX + TexY * MipSizeU];
						DataType *PreMipTexData00 = &(TextureMipData[Mip - 1])[PrevMipTexX + PrevMipTexY * PrevMipSizeU];
						DataType *PreMipTexData01 = &(TextureMipData[Mip - 1])[PrevMipTexX + PrevMipTexY1 * PrevMipSizeU];
						DataType *PreMipTexData10 = &(TextureMipData[Mip - 1])[PrevMipTexX1 + PrevMipTexY * PrevMipSizeU];
						DataType *PreMipTexData11 = &(TextureMipData[Mip - 1])[PrevMipTexX1 + PrevMipTexY1 * PrevMipSizeU];

						// Lerp weightmap data
						BiLerpTextureData<DataType>(TexData, PreMipTexData00, PreMipTexData10, PreMipTexData01, PreMipTexData11, fPrevMipTexFracX, fPrevMipTexFracY);
					}
				}

				// Record the areas we updated
				if (TextureDataInfo)
				{
					int32 TexX1 = (MipSubsectionSizeQuads + 1) * SubsectionX + VertX1;
					int32 TexY1 = (MipSubsectionSizeQuads + 1) * SubsectionY + VertY1;
					int32 TexX2 = (MipSubsectionSizeQuads + 1) * SubsectionX + VertX2;
					int32 TexY2 = (MipSubsectionSizeQuads + 1) * SubsectionY + VertY2;
					TextureDataInfo->AddMipUpdateRegion(Mip, TexX1, TexY1, TexX2, TexY2);
				}

				// Copy current mip values to prev as we move to the next mip.
				PrevMipSubsectionSizeQuads = MipSubsectionSizeQuads;
				InvPrevMipSubsectionSizeQuads = InvMipSubsectionSizeQuads;

				PrevMipSizeU = MipSizeU;
				PrevMipSizeV = MipSizeV;

				// Use this mip's area as we move to the next mip
				PrevMipSubX1 = MipSubX1;
				PrevMipSubY1 = MipSubY1;
				PrevMipSubX2 = MipSubX2;
				PrevMipSubY2 = MipSubY2;
			}
		}
	}

	// Handle mips that have texels from multiple subsections
	// not valid weight data, so just average the texels of the previous mip.
	for (int32 Mip = MaxWholeSubsectionMip + 1;; ++Mip)
	{
		int32 MipSubsectionSizeQuads = ((InSubsectionSizeQuads + 1) >> Mip) - 1;
		checkSlow(MipSubsectionSizeQuads <= 0);

		int32 MipSizeU = FMath::Max<int32>(WeightmapSizeU >> Mip, 1);
		int32 MipSizeV = FMath::Max<int32>(WeightmapSizeV >> Mip, 1);

		int32 PrevMipSizeU = FMath::Max<int32>(WeightmapSizeU >> (Mip - 1), 1);
		int32 PrevMipSizeV = FMath::Max<int32>(WeightmapSizeV >> (Mip - 1), 1);

		for (int32 Y = 0; Y < MipSizeV; Y++)
		{
			for (int32 X = 0; X < MipSizeU; X++)
			{
				DataType* TexData = &(TextureMipData[Mip])[X + Y * MipSizeU];

				DataType *PreMipTexData00 = &(TextureMipData[Mip - 1])[(X * 2 + 0) + (Y * 2 + 0)  * PrevMipSizeU];
				DataType *PreMipTexData01 = &(TextureMipData[Mip - 1])[(X * 2 + 0) + (Y * 2 + 1)  * PrevMipSizeU];
				DataType *PreMipTexData10 = &(TextureMipData[Mip - 1])[(X * 2 + 1) + (Y * 2 + 0)  * PrevMipSizeU];
				DataType *PreMipTexData11 = &(TextureMipData[Mip - 1])[(X * 2 + 1) + (Y * 2 + 1)  * PrevMipSizeU];

				AverageTexData<DataType>(TexData, PreMipTexData00, PreMipTexData10, PreMipTexData01, PreMipTexData11);
			}
		}

		if (TextureDataInfo)
		{
			// These mip sizes are small enough that we may as well just update the whole mip.
			TextureDataInfo->AddMipUpdateRegion(Mip, 0, 0, MipSizeU - 1, MipSizeV - 1);
		}

		if (MipSizeU == 1 && MipSizeV == 1)
		{
			break;
		}
	}
}

void ULandscapeComponent::UpdateWeightmapMips(int32 InNumSubsections, int32 InSubsectionSizeQuads, UTexture2D* WeightmapTexture, TArray<FColor*>& WeightmapTextureMipData, int32 ComponentX1/*=0*/, int32 ComponentY1/*=0*/, int32 ComponentX2/*=MAX_int32*/, int32 ComponentY2/*=MAX_int32*/, struct FLandscapeTextureDataInfo* TextureDataInfo/*=NULL*/)
{
	UpdateMipsTempl<FColor>(InNumSubsections, InSubsectionSizeQuads, WeightmapTexture, WeightmapTextureMipData, ComponentX1, ComponentY1, ComponentX2, ComponentY2, TextureDataInfo);
}

void ULandscapeComponent::UpdateDataMips(int32 InNumSubsections, int32 InSubsectionSizeQuads, UTexture2D* Texture, TArray<uint8*>& TextureMipData, int32 ComponentX1/*=0*/, int32 ComponentY1/*=0*/, int32 ComponentX2/*=MAX_int32*/, int32 ComponentY2/*=MAX_int32*/, struct FLandscapeTextureDataInfo* TextureDataInfo/*=NULL*/)
{
	UpdateMipsTempl<uint8>(InNumSubsections, InSubsectionSizeQuads, Texture, TextureMipData, ComponentX1, ComponentY1, ComponentX2, ComponentY2, TextureDataInfo);
}

float ULandscapeComponent::GetLayerWeightAtLocation(const FVector& InLocation, ULandscapeLayerInfoObject* LayerInfo, TArray<uint8>* LayerCache)
{
	// Allocate and discard locally if no external cache is passed in.
	TArray<uint8> LocalCache;
	if (LayerCache == NULL)
	{
		LayerCache = &LocalCache;
	}

	// Fill the cache if necessary
	if (LayerCache->Num() == 0)
	{
		FLandscapeComponentDataInterface CDI(this);
		if (!CDI.GetWeightmapTextureData(LayerInfo, *LayerCache))
		{
			// no data for this layer for this component.
			return 0.0f;
		}
	}

	// Find location
	// TODO: Root landscape isn't always loaded, would Proxy suffice?
	if (ALandscape* Landscape = GetLandscapeActor())
	{
		const FVector DrawScale = Landscape->GetRootComponent()->RelativeScale3D;
		float TestX = (InLocation.X - Landscape->GetActorLocation().X) / DrawScale.X - (float)GetSectionBase().X;
		float TestY = (InLocation.Y - Landscape->GetActorLocation().Y) / DrawScale.Y - (float)GetSectionBase().Y;

		// Find data
		int32 X1 = FMath::FloorToInt(TestX);
		int32 Y1 = FMath::FloorToInt(TestY);
		int32 X2 = FMath::CeilToInt(TestX);
		int32 Y2 = FMath::CeilToInt(TestY);

		int32 Stride = (SubsectionSizeQuads + 1) * NumSubsections;

		// Min is to prevent the sampling of the final column from overflowing
		int32 IdxX1 = FMath::Min<int32>(((X1 / SubsectionSizeQuads) * (SubsectionSizeQuads + 1)) + (X1 % SubsectionSizeQuads), Stride - 1);
		int32 IdxY1 = FMath::Min<int32>(((Y1 / SubsectionSizeQuads) * (SubsectionSizeQuads + 1)) + (Y1 % SubsectionSizeQuads), Stride - 1);
		int32 IdxX2 = FMath::Min<int32>(((X2 / SubsectionSizeQuads) * (SubsectionSizeQuads + 1)) + (X2 % SubsectionSizeQuads), Stride - 1);
		int32 IdxY2 = FMath::Min<int32>(((Y2 / SubsectionSizeQuads) * (SubsectionSizeQuads + 1)) + (Y2 % SubsectionSizeQuads), Stride - 1);

		// sample
		float Sample11 = (float)((*LayerCache)[IdxX1 + Stride*IdxY1]) / 255.0f;
		float Sample21 = (float)((*LayerCache)[IdxX2 + Stride*IdxY1]) / 255.0f;
		float Sample12 = (float)((*LayerCache)[IdxX1 + Stride*IdxY2]) / 255.0f;
		float Sample22 = (float)((*LayerCache)[IdxX2 + Stride*IdxY2]) / 255.0f;

		float LerpX = FMath::Fractional(TestX);
		float LerpY = FMath::Fractional(TestY);

		// Bilinear interpolate
		return FMath::Lerp(
			FMath::Lerp(Sample11, Sample21, LerpX),
			FMath::Lerp(Sample12, Sample22, LerpX),
			LerpY);
	}
	
	return 0.f;	//if landscape is null we just return 0 instead of crashing. Seen cases where this happens, seems like a bug?
}

void ULandscapeComponent::GetComponentExtent(int32& MinX, int32& MinY, int32& MaxX, int32& MaxY) const
{
	MinX = FMath::Min(SectionBaseX, MinX);
	MinY = FMath::Min(SectionBaseY, MinY);
	MaxX = FMath::Max(SectionBaseX + ComponentSizeQuads, MaxX);
	MaxY = FMath::Max(SectionBaseY + ComponentSizeQuads, MaxY);
}

//
// ALandscape
//

#define MAX_LANDSCAPE_SUBSECTIONS 2

void ULandscapeInfo::GetComponentsInRegion(int32 X1, int32 Y1, int32 X2, int32 Y2, TSet<ULandscapeComponent*>& OutComponents)
{
	// Find component range for this block of data
	// X2/Y2 Coordinates are "inclusive" max values
	int32 ComponentIndexX1, ComponentIndexY1, ComponentIndexX2, ComponentIndexY2;
	ALandscape::CalcComponentIndicesOverlap(X1, Y1, X2, Y2, ComponentSizeQuads, ComponentIndexX1, ComponentIndexY1, ComponentIndexX2, ComponentIndexY2);

	for (int32 ComponentIndexY = ComponentIndexY1; ComponentIndexY <= ComponentIndexY2; ComponentIndexY++)
	{
		for (int32 ComponentIndexX = ComponentIndexX1; ComponentIndexX <= ComponentIndexX2; ComponentIndexX++)
		{
			ULandscapeComponent* Component = XYtoComponentMap.FindRef(FIntPoint(ComponentIndexX, ComponentIndexY));
			if (Component && !FLevelUtils::IsLevelLocked(Component->GetLandscapeProxy()->GetLevel()) && FLevelUtils::IsLevelVisible(Component->GetLandscapeProxy()->GetLevel()))
			{
				OutComponents.Add(Component);
			}
		}
	}
}

// A struct to remember where we have spare texture channels.
struct FWeightmapTextureAllocation
{
	int32 X;
	int32 Y;
	int32 ChannelsInUse;
	UTexture2D* Texture;
	FColor* TextureData;

	FWeightmapTextureAllocation(int32 InX, int32 InY, int32 InChannels, UTexture2D* InTexture, FColor* InTextureData)
		: X(InX)
		, Y(InY)
		, ChannelsInUse(InChannels)
		, Texture(InTexture)
		, TextureData(InTextureData)
	{}
};

// A struct to hold the info about each texture chunk of the total heightmap
struct FHeightmapInfo
{
	int32 HeightmapSizeU;
	int32 HeightmapSizeV;
	UTexture2D* HeightmapTexture;
	TArray<FColor*> HeightmapTextureMipData;
};

TArray<FName> ALandscapeProxy::GetLayersFromMaterial(UMaterialInterface* Material)
{
	TArray<FName> Result;

	if (Material)
	{
		const TArray<UMaterialExpression*>& Expressions = Material->GetMaterial()->Expressions;

		// TODO: *Unconnected* layer expressions?
		for (UMaterialExpression* Expression : Expressions)
		{
			if (auto LayerWeightExpression = Cast<UMaterialExpressionLandscapeLayerWeight>(Expression))
			{
				Result.AddUnique(LayerWeightExpression->ParameterName);
			}
			else if (auto LayerSampleExpression = Cast<UMaterialExpressionLandscapeLayerSample>(Expression))
			{
				Result.AddUnique(LayerSampleExpression->ParameterName);
			}
			else if (auto LayerSwitchExpression = Cast<UMaterialExpressionLandscapeLayerSwitch>(Expression))
			{
				Result.AddUnique(LayerSwitchExpression->ParameterName);
			}
			else if (auto LayerBlendExpression = Cast<UMaterialExpressionLandscapeLayerBlend>(Expression))
			{
				for (const auto& ExpressionLayer : LayerBlendExpression->Layers)
				{
					Result.AddUnique(ExpressionLayer.LayerName);
				}
			}
		}
	}

	return Result;
}

TArray<FName> ALandscapeProxy::GetLayersFromMaterial() const
{
	return GetLayersFromMaterial(LandscapeMaterial);
}

ULandscapeLayerInfoObject* ALandscapeProxy::CreateLayerInfo(const TCHAR* LayerName, ULevel* Level)
{
	FName LayerObjectName = FName(*FString::Printf(TEXT("LayerInfoObject_%s"), LayerName));
	FString Path = Level->GetOutermost()->GetName() + TEXT("_sharedassets/");
	if (Path.StartsWith("/Temp/"))
	{
		Path = FString("/Game/") + Path.RightChop(FString("/Temp/").Len());
	}
	FString PackageName = Path + LayerObjectName.ToString();
	FString PackageFilename;
	int32 Suffix = 1;
	while (FPackageName::DoesPackageExist(PackageName, NULL, &PackageFilename))
	{
		LayerObjectName = FName(*FString::Printf(TEXT("LayerInfoObject_%s_%d"), LayerName, Suffix));
		PackageName = Path + LayerObjectName.ToString();
		Suffix++;
	}
	UPackage* Package = CreatePackage(NULL, *PackageName);
	ULandscapeLayerInfoObject* LayerInfo = NewObject<ULandscapeLayerInfoObject>(Package, LayerObjectName, RF_Public | RF_Standalone | RF_Transactional);
	LayerInfo->LayerName = LayerName;

	return LayerInfo;
}

ULandscapeLayerInfoObject* ALandscapeProxy::CreateLayerInfo(const TCHAR* LayerName)
{
	ULandscapeLayerInfoObject* LayerInfo = ALandscapeProxy::CreateLayerInfo(LayerName, GetLevel());

	check(LayerInfo);

	ULandscapeInfo* LandscapeInfo = GetLandscapeInfo();
	if (LandscapeInfo)
	{
		int32 Index = LandscapeInfo->GetLayerInfoIndex(LayerName, this);
		if (Index == INDEX_NONE)
		{
			LandscapeInfo->Layers.Add(FLandscapeInfoLayerSettings(LayerInfo, this));
		}
		else
		{
			LandscapeInfo->Layers[Index].LayerInfoObj = LayerInfo;
		}
	}

	return LayerInfo;
}

#define HEIGHTDATA(X,Y) (HeightData[ FMath::Clamp<int32>(Y,0,VertsY) * VertsX + FMath::Clamp<int32>(X,0,VertsX) ])
void ALandscapeProxy::Import(FGuid Guid, int32 VertsX, int32 VertsY,
	int32 InComponentSizeQuads, int32 InNumSubsections, int32 InSubsectionSizeQuads,
	const uint16* HeightData, const TCHAR* HeightmapFileName,
	const TArray<FLandscapeImportLayerInfo>& ImportLayerInfos)
{
	GWarn->BeginSlowTask(LOCTEXT("BeingImportingLandscapeTask", "Importing Landscape"), true);

	ComponentSizeQuads = InComponentSizeQuads;
	NumSubsections = InNumSubsections;
	SubsectionSizeQuads = InSubsectionSizeQuads;
	LandscapeGuid = Guid;

	MarkPackageDirty();

	// Create and initialize landscape info object
	GetLandscapeInfo(true)->RegisterActor(this);

	int32 NumPatchesX = (VertsX - 1);
	int32 NumPatchesY = (VertsY - 1);

	int32 NumSectionsX = NumPatchesX / ComponentSizeQuads;
	int32 NumSectionsY = NumPatchesY / ComponentSizeQuads;

	LandscapeComponents.Empty(NumSectionsX * NumSectionsY);

	for (int32 Y = 0; Y < NumSectionsY; Y++)
	{
		for (int32 X = 0; X < NumSectionsX; X++)
		{
			// The number of quads
			int32 NumQuadsX = NumPatchesX;
			int32 NumQuadsY = NumPatchesY;

			int32 BaseX = X * ComponentSizeQuads;
			int32 BaseY = Y * ComponentSizeQuads;

			ULandscapeComponent* LandscapeComponent = NewObject<ULandscapeComponent>(this, NAME_None, RF_Transactional);
			LandscapeComponent->SetRelativeLocation(FVector(BaseX, BaseY, 0));
			LandscapeComponent->AttachTo(GetRootComponent(), NAME_None);
			LandscapeComponents.Add(LandscapeComponent);
			LandscapeComponent->Init(
				BaseX, BaseY,
				ComponentSizeQuads,
				NumSubsections,
				SubsectionSizeQuads
				);

			// Assign shared properties
			LandscapeComponent->bCastStaticShadow = bCastStaticShadow;
			LandscapeComponent->bCastShadowAsTwoSided = bCastShadowAsTwoSided;
		}
	}

#define MAX_HEIGHTMAP_TEXTURE_SIZE 512

	int32 ComponentSizeVerts = NumSubsections * (SubsectionSizeQuads + 1);
	int32 ComponentsPerHeightmap = MAX_HEIGHTMAP_TEXTURE_SIZE / ComponentSizeVerts;

	// Ensure that we don't pack so many heightmaps into a texture that their lowest LOD isn't guaranteed to be resident
	ComponentsPerHeightmap = FMath::Min(ComponentsPerHeightmap, 1 << (UTexture2D::GetMinTextureResidentMipCount() - 2));

	// Count how many heightmaps we need and the X dimension of the final heightmap
	int32 NumHeightmapsX = 1;
	int32 FinalComponentsX = NumSectionsX;
	while (FinalComponentsX > ComponentsPerHeightmap)
	{
		FinalComponentsX -= ComponentsPerHeightmap;
		NumHeightmapsX++;
	}
	// Count how many heightmaps we need and the Y dimension of the final heightmap
	int32 NumHeightmapsY = 1;
	int32 FinalComponentsY = NumSectionsY;
	while (FinalComponentsY > ComponentsPerHeightmap)
	{
		FinalComponentsY -= ComponentsPerHeightmap;
		NumHeightmapsY++;
	}

	TArray<FHeightmapInfo> HeightmapInfos;

	for (int32 HmY = 0; HmY < NumHeightmapsY; HmY++)
	{
		for (int32 HmX = 0; HmX < NumHeightmapsX; HmX++)
		{
			FHeightmapInfo& HeightmapInfo = HeightmapInfos[HeightmapInfos.AddZeroed()];

			// make sure the heightmap UVs are powers of two.
			HeightmapInfo.HeightmapSizeU = (1 << FMath::CeilLogTwo(((HmX == NumHeightmapsX - 1) ? FinalComponentsX : ComponentsPerHeightmap)*ComponentSizeVerts));
			HeightmapInfo.HeightmapSizeV = (1 << FMath::CeilLogTwo(((HmY == NumHeightmapsY - 1) ? FinalComponentsY : ComponentsPerHeightmap)*ComponentSizeVerts));

			// Construct the heightmap textures
			HeightmapInfo.HeightmapTexture = CreateLandscapeTexture(HeightmapInfo.HeightmapSizeU, HeightmapInfo.HeightmapSizeV, TEXTUREGROUP_Terrain_Heightmap, TSF_BGRA8);

			int32 MipSubsectionSizeQuads = SubsectionSizeQuads;
			int32 MipSizeU = HeightmapInfo.HeightmapSizeU;
			int32 MipSizeV = HeightmapInfo.HeightmapSizeV;
			while (MipSizeU > 1 && MipSizeV > 1 && MipSubsectionSizeQuads >= 1)
			{
				int32 MipIndex = HeightmapInfo.HeightmapTextureMipData.Num();
				FColor* HeightmapTextureData = (FColor*)HeightmapInfo.HeightmapTexture->Source.LockMip(MipIndex);
				FMemory::Memzero(HeightmapTextureData, MipSizeU*MipSizeV*sizeof(FColor));
				HeightmapInfo.HeightmapTextureMipData.Add(HeightmapTextureData);

				MipSizeU >>= 1;
				MipSizeV >>= 1;

				MipSubsectionSizeQuads = ((MipSubsectionSizeQuads + 1) >> 1) - 1;
			}
		}
	}

	const FVector DrawScale3D = GetRootComponent()->RelativeScale3D;

	// Calculate the normals for each of the two triangles per quad.
	FVector* VertexNormals = new FVector[(NumPatchesX + 1)*(NumPatchesY + 1)];
	FMemory::Memzero(VertexNormals, (NumPatchesX + 1)*(NumPatchesY + 1)*sizeof(FVector));
	for (int32 QuadY = 0; QuadY < NumPatchesY; QuadY++)
	{
		for (int32 QuadX = 0; QuadX < NumPatchesX; QuadX++)
		{
			FVector Vert00 = FVector(0.0f, 0.0f, ((float)HEIGHTDATA(QuadX + 0, QuadY + 0) - 32768.0f)*LANDSCAPE_ZSCALE) * DrawScale3D;
			FVector Vert01 = FVector(0.0f, 1.0f, ((float)HEIGHTDATA(QuadX + 0, QuadY + 1) - 32768.0f)*LANDSCAPE_ZSCALE) * DrawScale3D;
			FVector Vert10 = FVector(1.0f, 0.0f, ((float)HEIGHTDATA(QuadX + 1, QuadY + 0) - 32768.0f)*LANDSCAPE_ZSCALE) * DrawScale3D;
			FVector Vert11 = FVector(1.0f, 1.0f, ((float)HEIGHTDATA(QuadX + 1, QuadY + 1) - 32768.0f)*LANDSCAPE_ZSCALE) * DrawScale3D;

			FVector FaceNormal1 = ((Vert00 - Vert10) ^ (Vert10 - Vert11)).GetSafeNormal();
			FVector FaceNormal2 = ((Vert11 - Vert01) ^ (Vert01 - Vert00)).GetSafeNormal();

			// contribute to the vertex normals.
			VertexNormals[(QuadX + 1 + (NumPatchesX + 1)*(QuadY + 0))] += FaceNormal1;
			VertexNormals[(QuadX + 0 + (NumPatchesX + 1)*(QuadY + 1))] += FaceNormal2;
			VertexNormals[(QuadX + 0 + (NumPatchesX + 1)*(QuadY + 0))] += FaceNormal1 + FaceNormal2;
			VertexNormals[(QuadX + 1 + (NumPatchesX + 1)*(QuadY + 1))] += FaceNormal1 + FaceNormal2;
		}
	}

	// Weight values for each layer for each component.
	TArray<TArray<TArray<uint8> > > ComponentWeightValues;
	ComponentWeightValues.AddZeroed(NumSectionsX*NumSectionsY);

	for (int32 ComponentY = 0; ComponentY < NumSectionsY; ComponentY++)
	{
		for (int32 ComponentX = 0; ComponentX < NumSectionsX; ComponentX++)
		{
			ULandscapeComponent* LandscapeComponent = LandscapeComponents[ComponentX + ComponentY*NumSectionsX];
			TArray<TArray<uint8> >& WeightValues = ComponentWeightValues[ComponentX + ComponentY*NumSectionsX];

			// Import alphamap data into local array and check for unused layers for this component.
			TArray<FLandscapeComponentAlphaInfo> EditingAlphaLayerData;
			for (int32 LayerIndex = 0; LayerIndex < ImportLayerInfos.Num(); LayerIndex++)
			{
				FLandscapeComponentAlphaInfo* NewAlphaInfo = new(EditingAlphaLayerData) FLandscapeComponentAlphaInfo(LandscapeComponent, LayerIndex);

				if (ImportLayerInfos[LayerIndex].LayerData.Num())
				{
					for (int32 AlphaY = 0; AlphaY <= LandscapeComponent->ComponentSizeQuads; AlphaY++)
					{
						const uint8* OldAlphaRowStart = &ImportLayerInfos[LayerIndex].LayerData[(AlphaY + LandscapeComponent->GetSectionBase().Y) * VertsX + (LandscapeComponent->GetSectionBase().X)];
						uint8* NewAlphaRowStart = &NewAlphaInfo->AlphaValues[AlphaY * (LandscapeComponent->ComponentSizeQuads + 1)];
						FMemory::Memcpy(NewAlphaRowStart, OldAlphaRowStart, LandscapeComponent->ComponentSizeQuads + 1);
					}
				}
			}

			for (int32 AlphaMapIndex = 0; AlphaMapIndex < EditingAlphaLayerData.Num(); AlphaMapIndex++)
			{
				if (EditingAlphaLayerData[AlphaMapIndex].IsLayerAllZero())
				{
					EditingAlphaLayerData.RemoveAt(AlphaMapIndex);
					AlphaMapIndex--;
				}
			}


			UE_LOG(LogLandscape, Log, TEXT("%s needs %d alphamaps"), *LandscapeComponent->GetName(), EditingAlphaLayerData.Num());

			// Calculate weightmap weights for this component
			WeightValues.Empty(EditingAlphaLayerData.Num());
			WeightValues.AddZeroed(EditingAlphaLayerData.Num());
			LandscapeComponent->WeightmapLayerAllocations.Empty(EditingAlphaLayerData.Num());

			TArray<bool> IsNoBlendArray;
			IsNoBlendArray.Empty(EditingAlphaLayerData.Num());
			IsNoBlendArray.AddZeroed(EditingAlphaLayerData.Num());

			for (int32 WeightLayerIndex = 0; WeightLayerIndex < WeightValues.Num(); WeightLayerIndex++)
			{
				// Lookup the original layer name
				WeightValues[WeightLayerIndex] = EditingAlphaLayerData[WeightLayerIndex].AlphaValues;
				new(LandscapeComponent->WeightmapLayerAllocations) FWeightmapLayerAllocationInfo(ImportLayerInfos[EditingAlphaLayerData[WeightLayerIndex].LayerIndex].LayerInfo);
				IsNoBlendArray[WeightLayerIndex] = ImportLayerInfos[EditingAlphaLayerData[WeightLayerIndex].LayerIndex].LayerInfo->bNoWeightBlend;
			}

			// Discard the temporary alpha data
			EditingAlphaLayerData.Empty();

			// For each layer...
			for (int32 WeightLayerIndex = WeightValues.Num() - 1; WeightLayerIndex >= 0; WeightLayerIndex--)
			{
				// ... multiply all lower layers'...
				for (int32 BelowWeightLayerIndex = WeightLayerIndex - 1; BelowWeightLayerIndex >= 0; BelowWeightLayerIndex--)
				{
					int32 TotalWeight = 0;

					if (IsNoBlendArray[BelowWeightLayerIndex])
					{
						continue; // skip no blend
					}

					// ... values by...
					for (int32 Idx = 0; Idx < WeightValues[WeightLayerIndex].Num(); Idx++)
					{
						// ... one-minus the current layer's values
						int32 NewValue = (int32)WeightValues[BelowWeightLayerIndex][Idx] * (int32)(255 - WeightValues[WeightLayerIndex][Idx]) / 255;
						WeightValues[BelowWeightLayerIndex][Idx] = (uint8)NewValue;
						TotalWeight += NewValue;
					}

					if (TotalWeight == 0)
					{
						// Remove the layer as it has no contribution
						WeightValues.RemoveAt(BelowWeightLayerIndex);
						LandscapeComponent->WeightmapLayerAllocations.RemoveAt(BelowWeightLayerIndex);
						IsNoBlendArray.RemoveAt(BelowWeightLayerIndex);

						// The current layer has been re-numbered
						WeightLayerIndex--;
					}
				}
			}

			// Weight normalization for total should be 255...
			if (WeightValues.Num())
			{
				for (int32 Idx = 0; Idx < WeightValues[0].Num(); Idx++)
				{
					int32 TotalWeight = 0;
					int32 MaxLayerIdx = -1;
					int32 MaxWeight = INT_MIN;

					for (int32 WeightLayerIndex = 0; WeightLayerIndex < WeightValues.Num(); WeightLayerIndex++)
					{
						if (!IsNoBlendArray[WeightLayerIndex])
						{
							int32 Weight = WeightValues[WeightLayerIndex][Idx];
							TotalWeight += Weight;
							if (MaxWeight < Weight)
							{
								MaxWeight = Weight;
								MaxLayerIdx = WeightLayerIndex;
							}
						}
					}

					if (TotalWeight == 0)
					{
						if (MaxLayerIdx >= 0)
						{
							WeightValues[MaxLayerIdx][Idx] = 255;
						}
					}
					else if (TotalWeight != 255)
					{
						// normalization...
						float Factor = 255.0f / TotalWeight;
						TotalWeight = 0;
						for (int32 WeightLayerIndex = 0; WeightLayerIndex < WeightValues.Num(); WeightLayerIndex++)
						{
							if (!IsNoBlendArray[WeightLayerIndex])
							{
								WeightValues[WeightLayerIndex][Idx] = (uint8)(Factor * WeightValues[WeightLayerIndex][Idx]);
								TotalWeight += WeightValues[WeightLayerIndex][Idx];
							}
						}

						if (255 - TotalWeight && MaxLayerIdx >= 0)
						{
							WeightValues[MaxLayerIdx][Idx] += 255 - TotalWeight;
						}
					}
				}
			}
		}
	}

	// Remember where we have spare texture channels.
	TArray<FWeightmapTextureAllocation> TextureAllocations;

	for (int32 ComponentY = 0; ComponentY < NumSectionsY; ComponentY++)
	{
		int32 HmY = ComponentY / ComponentsPerHeightmap;
		int32 HeightmapOffsetY = (ComponentY - ComponentsPerHeightmap*HmY) * NumSubsections * (SubsectionSizeQuads + 1);

		for (int32 ComponentX = 0; ComponentX < NumSectionsX; ComponentX++)
		{
			int32 HmX = ComponentX / ComponentsPerHeightmap;
			FHeightmapInfo& HeightmapInfo = HeightmapInfos[HmX + HmY * NumHeightmapsX];

			ULandscapeComponent* LandscapeComponent = LandscapeComponents[ComponentX + ComponentY*NumSectionsX];

			// Lookup array of weight values for this component.
			TArray<TArray<uint8> >& WeightValues = ComponentWeightValues[ComponentX + ComponentY*NumSectionsX];

			// Heightmap offsets
			int32 HeightmapOffsetX = (ComponentX - ComponentsPerHeightmap*HmX) * NumSubsections * (SubsectionSizeQuads + 1);

			LandscapeComponent->HeightmapScaleBias = FVector4(1.0f / (float)HeightmapInfo.HeightmapSizeU, 1.0f / (float)HeightmapInfo.HeightmapSizeV, (float)((HeightmapOffsetX)) / (float)HeightmapInfo.HeightmapSizeU, ((float)(HeightmapOffsetY)) / (float)HeightmapInfo.HeightmapSizeV);
			LandscapeComponent->HeightmapTexture = HeightmapInfo.HeightmapTexture;

			// Weightmap is sized the same as the component
			int32 WeightmapSize = (SubsectionSizeQuads + 1) * NumSubsections;
			// Should be power of two
			check(((WeightmapSize - 1) & WeightmapSize) == 0);

			LandscapeComponent->WeightmapScaleBias = FVector4(1.0f / (float)WeightmapSize, 1.0f / (float)WeightmapSize, 0.5f / (float)WeightmapSize, 0.5f / (float)WeightmapSize);
			LandscapeComponent->WeightmapSubsectionOffset = (float)(SubsectionSizeQuads + 1) / (float)WeightmapSize;

			// Pointers to the texture data where we'll store each layer. Stride is 4 (FColor)
			TArray<uint8*> WeightmapTextureDataPointers;

			UE_LOG(LogLandscape, Log, TEXT("%s needs %d weightmap channels"), *LandscapeComponent->GetName(), WeightValues.Num());

			// Find texture channels to store each layer.
			int32 LayerIndex = 0;
			while (LayerIndex < WeightValues.Num())
			{
				int32 RemainingLayers = WeightValues.Num() - LayerIndex;

				int32 BestAllocationIndex = -1;

				// if we need less than 4 channels, try to find them somewhere to put all of them
				if (RemainingLayers < 4)
				{
					int32 BestDistSquared = MAX_int32;
					for (int32 TryAllocIdx = 0; TryAllocIdx < TextureAllocations.Num(); TryAllocIdx++)
					{
						if (TextureAllocations[TryAllocIdx].ChannelsInUse + RemainingLayers <= 4)
						{
							FWeightmapTextureAllocation& TryAllocation = TextureAllocations[TryAllocIdx];
							int32 TryDistSquared = FMath::Square(TryAllocation.X - ComponentX) + FMath::Square(TryAllocation.Y - ComponentY);
							if (TryDistSquared < BestDistSquared)
							{
								BestDistSquared = TryDistSquared;
								BestAllocationIndex = TryAllocIdx;
							}
						}
					}
				}

				if (BestAllocationIndex != -1)
				{
					FWeightmapTextureAllocation& Allocation = TextureAllocations[BestAllocationIndex];
					FLandscapeWeightmapUsage& WeightmapUsage = WeightmapUsageMap.FindChecked(Allocation.Texture);

					UE_LOG(LogLandscape, Log, TEXT("  ==> Storing %d channels starting at %s[%d]"), RemainingLayers, *Allocation.Texture->GetName(), Allocation.ChannelsInUse);

					for (int32 i = 0; i < RemainingLayers; i++)
					{
						LandscapeComponent->WeightmapLayerAllocations[LayerIndex + i].WeightmapTextureIndex = LandscapeComponent->WeightmapTextures.Num();
						LandscapeComponent->WeightmapLayerAllocations[LayerIndex + i].WeightmapTextureChannel = Allocation.ChannelsInUse;
						WeightmapUsage.ChannelUsage[Allocation.ChannelsInUse] = LandscapeComponent;
						switch (Allocation.ChannelsInUse)
						{
						case 1:
							WeightmapTextureDataPointers.Add((uint8*)&Allocation.TextureData->G);
							break;
						case 2:
							WeightmapTextureDataPointers.Add((uint8*)&Allocation.TextureData->B);
							break;
						case 3:
							WeightmapTextureDataPointers.Add((uint8*)&Allocation.TextureData->A);
							break;
						default:
							// this should not occur.
							check(0);

						}
						Allocation.ChannelsInUse++;
					}

					LayerIndex += RemainingLayers;
					LandscapeComponent->WeightmapTextures.Add(Allocation.Texture);
				}
				else
				{
					// We couldn't find a suitable place for these layers, so lets make a new one.
					UTexture2D* WeightmapTexture = CreateLandscapeTexture(WeightmapSize, WeightmapSize, TEXTUREGROUP_Terrain_Weightmap, TSF_BGRA8);
					FColor* MipData = (FColor*)WeightmapTexture->Source.LockMip(0);

					int32 ThisAllocationLayers = FMath::Min<int32>(RemainingLayers, 4);
					new(TextureAllocations)FWeightmapTextureAllocation(ComponentX, ComponentY, ThisAllocationLayers, WeightmapTexture, MipData);
					FLandscapeWeightmapUsage& WeightmapUsage = WeightmapUsageMap.Add(WeightmapTexture, FLandscapeWeightmapUsage());

					UE_LOG(LogLandscape, Log, TEXT("  ==> Storing %d channels in new texture %s"), ThisAllocationLayers, *WeightmapTexture->GetName());

					WeightmapTextureDataPointers.Add((uint8*)&MipData->R);
					LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 0].WeightmapTextureIndex = LandscapeComponent->WeightmapTextures.Num();
					LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 0].WeightmapTextureChannel = 0;
					WeightmapUsage.ChannelUsage[0] = LandscapeComponent;

					if (ThisAllocationLayers > 1)
					{
						WeightmapTextureDataPointers.Add((uint8*)&MipData->G);
						LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 1].WeightmapTextureIndex = LandscapeComponent->WeightmapTextures.Num();
						LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 1].WeightmapTextureChannel = 1;
						WeightmapUsage.ChannelUsage[1] = LandscapeComponent;

						if (ThisAllocationLayers > 2)
						{
							WeightmapTextureDataPointers.Add((uint8*)&MipData->B);
							LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 2].WeightmapTextureIndex = LandscapeComponent->WeightmapTextures.Num();
							LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 2].WeightmapTextureChannel = 2;
							WeightmapUsage.ChannelUsage[2] = LandscapeComponent;

							if (ThisAllocationLayers > 3)
							{
								WeightmapTextureDataPointers.Add((uint8*)&MipData->A);
								LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 3].WeightmapTextureIndex = LandscapeComponent->WeightmapTextures.Num();
								LandscapeComponent->WeightmapLayerAllocations[LayerIndex + 3].WeightmapTextureChannel = 3;
								WeightmapUsage.ChannelUsage[3] = LandscapeComponent;
							}
						}
					}
					LandscapeComponent->WeightmapTextures.Add(WeightmapTexture);

					LayerIndex += ThisAllocationLayers;
				}
			}
			check(WeightmapTextureDataPointers.Num() == WeightValues.Num());

			FVector* LocalVerts = new FVector[FMath::Square(ComponentSizeQuads + 1)];

			for (int32 SubsectionY = 0; SubsectionY < NumSubsections; SubsectionY++)
			{
				for (int32 SubsectionX = 0; SubsectionX < NumSubsections; SubsectionX++)
				{
					for (int32 SubY = 0; SubY <= SubsectionSizeQuads; SubY++)
					{
						for (int32 SubX = 0; SubX <= SubsectionSizeQuads; SubX++)
						{
							// X/Y of the vertex we're looking at in component's coordinates.
							int32 CompX = SubsectionSizeQuads * SubsectionX + SubX;
							int32 CompY = SubsectionSizeQuads * SubsectionY + SubY;

							// X/Y of the vertex we're looking indexed into the texture data
							int32 TexX = (SubsectionSizeQuads + 1) * SubsectionX + SubX;
							int32 TexY = (SubsectionSizeQuads + 1) * SubsectionY + SubY;

							int32 WeightSrcDataIdx = CompY * (ComponentSizeQuads + 1) + CompX;
							int32 HeightTexDataIdx = (HeightmapOffsetX + TexX) + (HeightmapOffsetY + TexY) * (HeightmapInfo.HeightmapSizeU);

							int32 WeightTexDataIdx = (TexX)+(TexY)* (WeightmapSize);

							// copy height and normal data
							uint16 HeightValue = HEIGHTDATA(CompX + LandscapeComponent->GetSectionBase().X, CompY + LandscapeComponent->GetSectionBase().Y);
							FVector Normal = VertexNormals[CompX + LandscapeComponent->GetSectionBase().X + (NumPatchesX + 1)*(CompY + LandscapeComponent->GetSectionBase().Y)].GetSafeNormal();

							HeightmapInfo.HeightmapTextureMipData[0][HeightTexDataIdx].R = HeightValue >> 8;
							HeightmapInfo.HeightmapTextureMipData[0][HeightTexDataIdx].G = HeightValue & 255;
							HeightmapInfo.HeightmapTextureMipData[0][HeightTexDataIdx].B = FMath::RoundToInt(127.5f * (Normal.X + 1.0f));
							HeightmapInfo.HeightmapTextureMipData[0][HeightTexDataIdx].A = FMath::RoundToInt(127.5f * (Normal.Y + 1.0f));

							for (int32 WeightmapIndex = 0; WeightmapIndex < WeightValues.Num(); WeightmapIndex++)
							{
								WeightmapTextureDataPointers[WeightmapIndex][WeightTexDataIdx * 4] = WeightValues[WeightmapIndex][WeightSrcDataIdx];
							}

							// Get local space verts
							FVector LocalVertex(CompX, CompY, LandscapeDataAccess::GetLocalHeight(HeightValue));
							LocalVerts[(LandscapeComponent->ComponentSizeQuads + 1) * CompY + CompX] = LocalVertex;
						}
					}
				}
			}

			LandscapeComponent->CachedLocalBox = FBox(LocalVerts, FMath::Square(ComponentSizeQuads + 1));
			delete[] LocalVerts;

			// Update MaterialInstance
			LandscapeComponent->UpdateMaterialInstances();
		}
	}

	// Unlock the weightmaps' base mips
	for (int32 AllocationIndex = 0; AllocationIndex < TextureAllocations.Num(); AllocationIndex++)
	{
		UTexture2D* WeightmapTexture = TextureAllocations[AllocationIndex].Texture;
		FColor* BaseMipData = TextureAllocations[AllocationIndex].TextureData;

		// Generate mips for weightmaps
		ULandscapeComponent::GenerateWeightmapMips(NumSubsections, SubsectionSizeQuads, WeightmapTexture, BaseMipData);

		WeightmapTexture->Source.UnlockMip(0);
		WeightmapTexture->PostEditChange();
	}

	delete[] VertexNormals;

	// Generate mipmaps for the components, and create the collision components
	for (int32 ComponentY = 0; ComponentY < NumSectionsY; ComponentY++)
	{
		for (int32 ComponentX = 0; ComponentX < NumSectionsX; ComponentX++)
		{
			int32 HmX = ComponentX / ComponentsPerHeightmap;
			int32 HmY = ComponentY / ComponentsPerHeightmap;
			FHeightmapInfo& HeightmapInfo = HeightmapInfos[HmX + HmY * NumHeightmapsX];

			ULandscapeComponent* LandscapeComponent = LandscapeComponents[ComponentX + ComponentY*NumSectionsX];
			LandscapeComponent->GenerateHeightmapMips(HeightmapInfo.HeightmapTextureMipData, ComponentX == NumSectionsX - 1 ? MAX_int32 : 0, ComponentY == NumSectionsY - 1 ? MAX_int32 : 0);
			LandscapeComponent->UpdateCollisionHeightData(HeightmapInfo.HeightmapTextureMipData[LandscapeComponent->CollisionMipLevel]);
			LandscapeComponent->UpdateCollisionLayerData();
		}
	}

	for (int32 HmIdx = 0; HmIdx < HeightmapInfos.Num(); HmIdx++)
	{
		FHeightmapInfo& HeightmapInfo = HeightmapInfos[HmIdx];

		// Add remaining mips down to 1x1 to heightmap texture. These do not represent quads and are just a simple averages of the previous mipmaps. 
		// These mips are not used for sampling in the vertex shader but could be sampled in the pixel shader.
		int32 Mip = HeightmapInfo.HeightmapTextureMipData.Num();
		int32 MipSizeU = (HeightmapInfo.HeightmapTexture->Source.GetSizeX()) >> Mip;
		int32 MipSizeV = (HeightmapInfo.HeightmapTexture->Source.GetSizeY()) >> Mip;
		while (MipSizeU > 1 && MipSizeV > 1)
		{
			HeightmapInfo.HeightmapTextureMipData.Add((FColor*)HeightmapInfo.HeightmapTexture->Source.LockMip(Mip));
			int32 PrevMipSizeU = (HeightmapInfo.HeightmapTexture->Source.GetSizeX()) >> (Mip - 1);
			int32 PrevMipSizeV = (HeightmapInfo.HeightmapTexture->Source.GetSizeY()) >> (Mip - 1);

			for (int32 Y = 0; Y < MipSizeV; Y++)
			{
				for (int32 X = 0; X < MipSizeU; X++)
				{
					FColor* TexData = &(HeightmapInfo.HeightmapTextureMipData[Mip])[X + Y * MipSizeU];

					FColor *PreMipTexData00 = &(HeightmapInfo.HeightmapTextureMipData[Mip - 1])[(X * 2 + 0) + (Y * 2 + 0)  * PrevMipSizeU];
					FColor *PreMipTexData01 = &(HeightmapInfo.HeightmapTextureMipData[Mip - 1])[(X * 2 + 0) + (Y * 2 + 1)  * PrevMipSizeU];
					FColor *PreMipTexData10 = &(HeightmapInfo.HeightmapTextureMipData[Mip - 1])[(X * 2 + 1) + (Y * 2 + 0)  * PrevMipSizeU];
					FColor *PreMipTexData11 = &(HeightmapInfo.HeightmapTextureMipData[Mip - 1])[(X * 2 + 1) + (Y * 2 + 1)  * PrevMipSizeU];

					TexData->R = (((int32)PreMipTexData00->R + (int32)PreMipTexData01->R + (int32)PreMipTexData10->R + (int32)PreMipTexData11->R) >> 2);
					TexData->G = (((int32)PreMipTexData00->G + (int32)PreMipTexData01->G + (int32)PreMipTexData10->G + (int32)PreMipTexData11->G) >> 2);
					TexData->B = (((int32)PreMipTexData00->B + (int32)PreMipTexData01->B + (int32)PreMipTexData10->B + (int32)PreMipTexData11->B) >> 2);
					TexData->A = (((int32)PreMipTexData00->A + (int32)PreMipTexData01->A + (int32)PreMipTexData10->A + (int32)PreMipTexData11->A) >> 2);
				}
			}
			Mip++;
			MipSizeU >>= 1;
			MipSizeV >>= 1;
		}

		for (int32 i = 0; i < HeightmapInfo.HeightmapTextureMipData.Num(); i++)
		{
			HeightmapInfo.HeightmapTexture->Source.UnlockMip(i);
		}
		HeightmapInfo.HeightmapTexture->PostEditChange();
	}

	if (GetLevel()->bIsVisible)
	{
		// Update our new components
		ReregisterAllComponents();
	}

	ReimportHeightmapFilePath = HeightmapFileName;

	ULandscapeInfo::RecreateLandscapeInfo(GetWorld(), false);

	GWarn->EndSlowTask();
}

bool ALandscapeProxy::ExportToRawMesh(int32 InExportLOD, FRawMesh& OutRawMesh) const
{
	TInlineComponentArray<ULandscapeComponent*> RegisteredLandscapeComponents;
	GetComponents<ULandscapeComponent>(RegisteredLandscapeComponents);

	const FIntRect LandscapeSectionRect = GetBoundingRect();
	const FVector2D LandscapeUVScale = FVector2D(1.0f, 1.0f) / FVector2D(LandscapeSectionRect.Size());

	// User specified LOD to export
	int32 LandscapeLODToExport = ExportLOD;
	if (InExportLOD != INDEX_NONE)
	{
		LandscapeLODToExport = FMath::Clamp<int32>(InExportLOD, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
	}

	// Export data for each component
	for (auto It = RegisteredLandscapeComponents.CreateConstIterator(); It; ++It)
	{
		ULandscapeComponent* Component = (*It);
		FLandscapeComponentDataInterface CDI(Component, LandscapeLODToExport);
		const int32 ComponentSizeQuadsLOD = ((Component->ComponentSizeQuads + 1) >> LandscapeLODToExport) - 1;
		const int32 SubsectionSizeQuadsLOD = ((Component->SubsectionSizeQuads + 1) >> LandscapeLODToExport) - 1;
		const FIntPoint ComponentOffsetQuads = Component->GetSectionBase() - LandscapeSectionOffset - LandscapeSectionRect.Min;
		const FVector2D ComponentUVOffsetLOD = FVector2D(ComponentOffsetQuads)*((float)ComponentSizeQuadsLOD / ComponentSizeQuads);
		const FVector2D ComponentUVScaleLOD = LandscapeUVScale*((float)ComponentSizeQuads / ComponentSizeQuadsLOD);

		const int32 NumFaces = FMath::Square(ComponentSizeQuadsLOD) * 2;
		const int32 NumVertices = NumFaces * 3;
		const int32 VerticesOffset = OutRawMesh.VertexPositions.Num();
		const int32 IndicesOffset = OutRawMesh.WedgeIndices.Num();

		//
		OutRawMesh.FaceMaterialIndices.AddZeroed(NumFaces);
		OutRawMesh.FaceSmoothingMasks.AddZeroed(NumFaces);

		OutRawMesh.VertexPositions.AddZeroed(NumVertices);
		OutRawMesh.WedgeIndices.AddZeroed(NumVertices);
		OutRawMesh.WedgeTangentX.AddZeroed(NumVertices);
		OutRawMesh.WedgeTangentY.AddZeroed(NumVertices);
		OutRawMesh.WedgeTangentZ.AddZeroed(NumVertices);
		OutRawMesh.WedgeTexCoords[0].AddZeroed(NumVertices);


		// Check if there are any holes
		TArray<uint8> VisDataMap;

		for (int32 AllocIdx = 0; AllocIdx < Component->WeightmapLayerAllocations.Num(); AllocIdx++)
		{
			FWeightmapLayerAllocationInfo& AllocInfo = Component->WeightmapLayerAllocations[AllocIdx];
			if (AllocInfo.LayerInfo == ALandscapeProxy::VisibilityLayer)
			{
				CDI.GetWeightmapTextureData(AllocInfo.LayerInfo, VisDataMap);
			}
		}

		const FIntPoint QuadPattern[6] =
		{
			//face 1
			FIntPoint(0, 0),
			FIntPoint(0, 1),
			FIntPoint(1, 1),
			//face 2
			FIntPoint(0, 0),
			FIntPoint(1, 1),
			FIntPoint(1, 0),
		};

		const int32 VisThreshold = 170;
		const int32 WeightMapSize = (SubsectionSizeQuadsLOD + 1) * Component->NumSubsections;
		uint32* Faces = OutRawMesh.WedgeIndices.GetData() + IndicesOffset;

		// Export verts
		int32 VertexIdx = VerticesOffset;
		for (int32 y = 0; y < ComponentSizeQuadsLOD; y++)
		{
			for (int32 x = 0; x < ComponentSizeQuadsLOD; x++)
			{
				// Fill indices
				{

					// Whether this vertex is in hole
					bool bInvisible = false;
					if (VisDataMap.Num())
					{
						int32 TexelX, TexelY;
						CDI.VertexXYToTexelXY(x, y, TexelX, TexelY);
						bInvisible = (VisDataMap[CDI.TexelXYToIndex(TexelX, TexelY)] >= VisThreshold);
					}

					// triangulation matches FLandscapeIndexBuffer constructor
					Faces[0] = VertexIdx;
					Faces[1] = bInvisible ? Faces[0] : VertexIdx + 1;
					Faces[2] = bInvisible ? Faces[0] : VertexIdx + 2;
					Faces += 3;

					Faces[0] = VertexIdx + 3;
					Faces[1] = bInvisible ? Faces[0] : VertexIdx + 4;
					Faces[2] = bInvisible ? Faces[0] : VertexIdx + 5;
					Faces += 3;
				}

				// Fill vertices
				for (int32 i = 0; i < ARRAY_COUNT(QuadPattern); i++)
				{
					int32 VertexX = x + QuadPattern[i].X;
					int32 VertexY = y + QuadPattern[i].Y;
					FVector LocalVertexPos = CDI.GetWorldVertex(VertexX, VertexY);

					FVector LocalTangentX, LocalTangentY, LocalTangentZ;
					CDI.GetLocalTangentVectors(VertexX, VertexY, LocalTangentX, LocalTangentY, LocalTangentZ);

					OutRawMesh.VertexPositions[VertexIdx] = LocalVertexPos;
					OutRawMesh.WedgeTangentX[VertexIdx] = LocalTangentX;
					OutRawMesh.WedgeTangentY[VertexIdx] = LocalTangentY;
					OutRawMesh.WedgeTangentZ[VertexIdx] = LocalTangentZ;

					OutRawMesh.WedgeTexCoords[0][VertexIdx] = (ComponentUVOffsetLOD + FVector2D(VertexX, VertexY))*ComponentUVScaleLOD;

					VertexIdx++;
				}
			}
		}
	}

	// Add lightmap UVs
	OutRawMesh.WedgeTexCoords[1].Append(OutRawMesh.WedgeTexCoords[0]);

	return true;
}

FIntRect ALandscapeProxy::GetBoundingRect() const
{
	FIntRect Rect(MAX_int32, MAX_int32, MIN_int32, MIN_int32);

	for (int32 CompIdx = 0; CompIdx < LandscapeComponents.Num(); CompIdx++)
	{
		Rect.Include(LandscapeComponents[CompIdx]->GetSectionBase());
	}

	if (LandscapeComponents.Num() > 0)
	{
		Rect.Max += FIntPoint(ComponentSizeQuads, ComponentSizeQuads);
		Rect -= LandscapeSectionOffset;
	}
	else
	{
		Rect = FIntRect();
	}

	return Rect;
}

bool ALandscape::HasAllComponent()
{
	ULandscapeInfo* Info = GetLandscapeInfo();
	if (Info && Info->XYtoComponentMap.Num() == LandscapeComponents.Num())
	{
		// all components are owned by this Landscape actor (no Landscape Proxies)
		return true;
	}
	return false;
}

bool ULandscapeInfo::GetLandscapeExtent(int32& MinX, int32& MinY, int32& MaxX, int32& MaxY) const
{
	MinX = MAX_int32;
	MinY = MAX_int32;
	MaxX = MIN_int32;
	MaxY = MIN_int32;

	// Find range of entire landscape
	for (auto& XYComponentPair : XYtoComponentMap)
	{
		const ULandscapeComponent* Comp = XYComponentPair.Value;
		Comp->GetComponentExtent(MinX, MinY, MaxX, MaxY);
	}
	return (MinX != MAX_int32);
}

bool ULandscapeInfo::GetSelectedExtent(int32& MinX, int32& MinY, int32& MaxX, int32& MaxY) const
{
	MinX = MinY = MAX_int32;
	MaxX = MaxY = MIN_int32;
	for (auto& SelectedPointPair : SelectedRegion)
	{
		int32 X, Y;
		ALandscape::UnpackKey(SelectedPointPair.Key, X, Y);
		if (MinX > X) MinX = X;
		if (MaxX < X) MaxX = X;
		if (MinY > Y) MinY = Y;
		if (MaxY < Y) MaxY = Y;
	}
	if (MinX != MAX_int32)
	{
		return true;
	}
	// if SelectedRegion is empty, try SelectedComponents
	for (const ULandscapeComponent* Comp : SelectedComponents)
	{
		Comp->GetComponentExtent(MinX, MinY, MaxX, MaxY);
	}
	return MinX != MAX_int32;
}

FVector ULandscapeInfo::GetLandscapeCenterPos(float& LengthZ, int32 MinX /*= MAX_INT*/, int32 MinY /*= MAX_INT*/, int32 MaxX /*= MIN_INT*/, int32 MaxY /*= MIN_INT*/)
{
	// MinZ, MaxZ is Local coordinate
	float MaxZ = -HALF_WORLD_MAX, MinZ = HALF_WORLD_MAX;
	const float ScaleZ = DrawScale.Z;

	if (MinX == MAX_int32)
	{
		// Find range of entire landscape
		for (auto It = XYtoComponentMap.CreateIterator(); It; ++It)
		{
			ULandscapeComponent* Comp = It.Value();
			Comp->GetComponentExtent(MinX, MinY, MaxX, MaxY);
		}

		const int32 Dist = (ComponentSizeQuads + 1) >> 1; // Should be same in ALandscapeGizmoActiveActor::SetTargetLandscape
		FVector2D MidPoint(((float)(MinX + MaxX)) / 2.0f, ((float)(MinY + MaxY)) / 2.0f);
		MinX = FMath::FloorToInt(MidPoint.X) - Dist;
		MaxX = FMath::CeilToInt(MidPoint.X) + Dist;
		MinY = FMath::FloorToInt(MidPoint.Y) - Dist;
		MaxY = FMath::CeilToInt(MidPoint.Y) + Dist;
		check(MidPoint.X == ((float)(MinX + MaxX)) / 2.0f && MidPoint.Y == ((float)(MinY + MaxY)) / 2.0f);
	}

	check(MinX != MAX_int32);
	//if (MinX != MAX_int32)
	{
		int32 CompX1, CompX2, CompY1, CompY2;
		ALandscape::CalcComponentIndicesOverlap(MinX, MinY, MaxX, MaxY, ComponentSizeQuads, CompX1, CompY1, CompX2, CompY2);
		for (int32 IndexY = CompY1; IndexY <= CompY2; ++IndexY)
		{
			for (int32 IndexX = CompX1; IndexX <= CompX2; ++IndexX)
			{
				ULandscapeComponent* Comp = XYtoComponentMap.FindRef(FIntPoint(IndexX, IndexY));
				if (Comp)
				{
					ULandscapeHeightfieldCollisionComponent* CollisionComp = Comp->CollisionComponent.Get();
					if (CollisionComp)
					{
						uint16* Heights = (uint16*)CollisionComp->CollisionHeightData.Lock(LOCK_READ_ONLY);
						int32 CollisionSizeVerts = CollisionComp->CollisionSizeQuads + 1;

						int32 StartX = FMath::Max(0, MinX - CollisionComp->GetSectionBase().X);
						int32 StartY = FMath::Max(0, MinY - CollisionComp->GetSectionBase().Y);
						int32 EndX = FMath::Min(CollisionSizeVerts, MaxX - CollisionComp->GetSectionBase().X + 1);
						int32 EndY = FMath::Min(CollisionSizeVerts, MaxY - CollisionComp->GetSectionBase().Y + 1);

						for (int32 Y = StartY; Y < EndY; ++Y)
						{
							for (int32 X = StartX; X < EndX; ++X)
							{
								float Height = LandscapeDataAccess::GetLocalHeight(Heights[X + Y*CollisionSizeVerts]);
								MaxZ = FMath::Max(Height, MaxZ);
								MinZ = FMath::Min(Height, MinZ);
							}
						}
						CollisionComp->CollisionHeightData.Unlock();
					}
				}
			}
		}
	}

	const float MarginZ = 3;
	if (MaxZ < MinZ)
	{
		MaxZ = +MarginZ;
		MinZ = -MarginZ;
	}
	LengthZ = (MaxZ - MinZ + 2 * MarginZ) * ScaleZ;

	const FVector LocalPosition(((float)(MinX + MaxX)) / 2.0f, ((float)(MinY + MaxY)) / 2.0f, MinZ - MarginZ);
	//return GetLandscapeProxy()->TransformLandscapeLocationToWorld(LocalPosition);
	return GetLandscapeProxy()->LandscapeActorToWorld().TransformPosition(LocalPosition);
}

bool ULandscapeInfo::IsValidPosition(int32 X, int32 Y)
{
	int32 CompX1, CompX2, CompY1, CompY2;
	ALandscape::CalcComponentIndicesOverlap(X, Y, X, Y, ComponentSizeQuads, CompX1, CompY1, CompX2, CompY2);
	if (XYtoComponentMap.FindRef(FIntPoint(CompX1, CompY1)))
	{
		return true;
	}
	if (XYtoComponentMap.FindRef(FIntPoint(CompX2, CompY2)))
	{
		return true;
	}
	return false;
}

void ULandscapeInfo::Export(const TArray<ULandscapeLayerInfoObject*>& LayerInfos, const TArray<FString>& Filenames)
{
	check(Filenames.Num() > 0);

	int32 MinX = MAX_int32;
	int32 MinY = MAX_int32;
	int32 MaxX = -MAX_int32;
	int32 MaxY = -MAX_int32;

	if (!GetLandscapeExtent(MinX, MinY, MaxX, MaxY))
	{
		return;
	}

	GWarn->BeginSlowTask(LOCTEXT("BeginExportingLandscapeTask", "Exporting Landscape"), true);

	FLandscapeEditDataInterface LandscapeEdit(this);

	TArray<uint8> HeightData;
	HeightData.AddZeroed((1 + MaxX - MinX)*(1 + MaxY - MinY)*sizeof(uint16));
	LandscapeEdit.GetHeightDataFast(MinX, MinY, MaxX, MaxY, (uint16*)HeightData.GetData(), 0);
	FFileHelper::SaveArrayToFile(HeightData, *Filenames[0]);

	for (int32 i = 1; i < Filenames.Num(); i++)
	{
		if (i <= LayerInfos.Num())
		{
			TArray<uint8> WeightData;
			WeightData.AddZeroed((1 + MaxX - MinX)*(1 + MaxY - MinY));
			ULandscapeLayerInfoObject* LayerInfo = LayerInfos[i - 1];
			if (LayerInfo)
			{
				LandscapeEdit.GetWeightDataFast(LayerInfo, MinX, MinY, MaxX, MaxY, WeightData.GetData(), 0);
			}
			FFileHelper::SaveArrayToFile(WeightData, *Filenames[i]);
		}
	}

	GWarn->EndSlowTask();
}

void ULandscapeInfo::ExportHeightmap(const FString& Filename)
{
	int32 MinX = MAX_int32;
	int32 MinY = MAX_int32;
	int32 MaxX = -MAX_int32;
	int32 MaxY = -MAX_int32;

	if (!GetLandscapeExtent(MinX, MinY, MaxX, MaxY))
	{
		return;
	}

	GWarn->BeginSlowTask(LOCTEXT("BeginExportingLandscapeHeightmapTask", "Exporting Landscape Heightmap"), true);

	FLandscapeEditDataInterface LandscapeEdit(this);

	TArray<uint8> HeightData;
	HeightData.AddZeroed((MaxX - MinX + 1) * (MaxY - MinY + 1) * sizeof(uint16));
	LandscapeEdit.GetHeightDataFast(MinX, MinY, MaxX, MaxY, (uint16*)HeightData.GetData(), 0);

	if (Filename.EndsWith(".png"))
	{
		IImageWrapperModule& ImageWrapperModule = FModuleManager::LoadModuleChecked<IImageWrapperModule>("ImageWrapper");
		IImageWrapperPtr ImageWrapper = ImageWrapperModule.CreateImageWrapper(EImageFormat::PNG);

		const TArray<uint8>* RawData = NULL;
		if (ImageWrapper->SetRaw(HeightData.GetData(), HeightData.Num(), (MaxX - MinX + 1), (MaxY - MinY + 1), ERGBFormat::Gray, 16))
		{
			HeightData = ImageWrapper->GetCompressed();
		}
	}

	FFileHelper::SaveArrayToFile(HeightData, *Filename);

	GWarn->EndSlowTask();
}

void ULandscapeInfo::ExportLayer(ULandscapeLayerInfoObject* LayerInfo, const FString& Filename)
{
	int32 MinX = MAX_int32;
	int32 MinY = MAX_int32;
	int32 MaxX = -MAX_int32;
	int32 MaxY = -MAX_int32;

	if (!GetLandscapeExtent(MinX, MinY, MaxX, MaxY))
	{
		return;
	}

	GWarn->BeginSlowTask(LOCTEXT("BeginExportingLandscapeWeightmapTask", "Exporting Landscape Layer Weightmap"), true);

	TArray<uint8> WeightData;
	WeightData.AddZeroed((MaxX - MinX + 1) * (MaxY - MinY + 1));
	if (LayerInfo)
	{
		FLandscapeEditDataInterface LandscapeEdit(this);
		LandscapeEdit.GetWeightDataFast(LayerInfo, MinX, MinY, MaxX, MaxY, WeightData.GetData(), 0);
	}

	if (Filename.EndsWith(".png"))
	{
		IImageWrapperModule& ImageWrapperModule = FModuleManager::LoadModuleChecked<IImageWrapperModule>("ImageWrapper");
		IImageWrapperPtr ImageWrapper = ImageWrapperModule.CreateImageWrapper(EImageFormat::PNG);

		const TArray<uint8>* RawData = NULL;
		if (ImageWrapper->SetRaw(WeightData.GetData(), WeightData.Num(), (MaxX - MinX + 1), (MaxY - MinY + 1), ERGBFormat::Gray, 8))
		{
			WeightData = ImageWrapper->GetCompressed();
		}
	}

	FFileHelper::SaveArrayToFile(WeightData, *Filename);

	GWarn->EndSlowTask();
}

void ULandscapeInfo::DeleteLayer(ULandscapeLayerInfoObject* LayerInfo)
{
	GWarn->BeginSlowTask(LOCTEXT("BeginDeletingLayerTask", "Deleting Layer"), true);

	// Remove data from all components
	FLandscapeEditDataInterface LandscapeEdit(this);
	LandscapeEdit.DeleteLayer(LayerInfo);

	// Remove from array
	for (int32 j = 0; j < Layers.Num(); j++)
	{
		if (Layers[j].LayerInfoObj && Layers[j].LayerInfoObj == LayerInfo)
		{
			Layers.RemoveAt(j);
			break;
		}
	}

	ALandscape* Landscape = LandscapeActor.Get();
	if (Landscape != NULL)
	{
		Landscape->Modify();
		Landscape->EditorLayerSettings.Remove(LayerInfo);
	}

	for (auto It = Proxies.CreateConstIterator(); It; ++It)
	{
		ALandscapeProxy* Proxy = *It;
		Proxy->Modify();
		Proxy->EditorLayerSettings.Remove(LayerInfo);
	}

	//UpdateLayerInfoMap();

	GWarn->EndSlowTask();
}

void ULandscapeInfo::ReplaceLayer(ULandscapeLayerInfoObject* FromLayerInfo, ULandscapeLayerInfoObject* ToLayerInfo)
{
	if (ensure(FromLayerInfo != ToLayerInfo))
	{
		GWarn->BeginSlowTask(LOCTEXT("BeginReplacingLayerTask", "Replacing Layer"), true);

		// Remove data from all components
		FLandscapeEditDataInterface LandscapeEdit(this);
		LandscapeEdit.ReplaceLayer(FromLayerInfo, ToLayerInfo);

		// Convert array
		for (int32 j = 0; j < Layers.Num(); j++)
		{
			if (Layers[j].LayerInfoObj && Layers[j].LayerInfoObj == FromLayerInfo)
			{
				Layers[j].LayerInfoObj = ToLayerInfo;
			}
		}

		ALandscape* Landscape = LandscapeActor.Get();
		if (Landscape != NULL)
		{
			Landscape->Modify();
			FLandscapeEditorLayerSettings* ToEditorLayerSettings = Landscape->EditorLayerSettings.FindByKey(ToLayerInfo);
			if (ToEditorLayerSettings != NULL)
			{
				// If the new layer already exists, simple remove the old layer
				Landscape->EditorLayerSettings.Remove(FromLayerInfo);
			}
			else
			{
				FLandscapeEditorLayerSettings* FromEditorLayerSettings = Landscape->EditorLayerSettings.FindByKey(FromLayerInfo);
				if (FromEditorLayerSettings != NULL)
				{
					// If only the old layer exists (most common case), change it to point to the new layer info
					FromEditorLayerSettings->LayerInfoObj = ToLayerInfo;
				}
				else
				{
					// If neither exists in the EditorLayerSettings cache, add it
					Landscape->EditorLayerSettings.Add(ToLayerInfo);
				}
			}
		}

		for (auto It = Proxies.CreateConstIterator(); It; ++It)
		{
			ALandscapeProxy* Proxy = *It;
			Proxy->Modify();
			FLandscapeEditorLayerSettings* ToEditorLayerSettings = Proxy->EditorLayerSettings.FindByKey(ToLayerInfo);
			if (ToEditorLayerSettings != NULL)
			{
				// If the new layer already exists, simple remove the old layer
				Proxy->EditorLayerSettings.Remove(FromLayerInfo);
			}
			else
			{
				FLandscapeEditorLayerSettings* FromEditorLayerSettings = Proxy->EditorLayerSettings.FindByKey(FromLayerInfo);
				if (FromEditorLayerSettings != NULL)
				{
					// If only the old layer exists (most common case), change it to point to the new layer info
					FromEditorLayerSettings->LayerInfoObj = ToLayerInfo;
				}
				else
				{
					// If neither exists in the EditorLayerSettings cache, add it
					Proxy->EditorLayerSettings.Add(ToLayerInfo);
				}
			}
		}

		//UpdateLayerInfoMap();

		GWarn->EndSlowTask();
	}
}

void ALandscapeProxy::EditorApplyScale(const FVector& DeltaScale, const FVector* PivotLocation, bool bAltDown, bool bShiftDown, bool bCtrlDown)
{
	FVector ModifiedScale = DeltaScale;

	// Lock X and Y scaling to the same value
	ModifiedScale.X = ModifiedScale.Y = (FMath::Abs(DeltaScale.X) > FMath::Abs(DeltaScale.Y)) ? DeltaScale.X : DeltaScale.Y;

	// Correct for attempts to scale to 0 on any axis
	FVector CurrentScale = GetRootComponent()->RelativeScale3D;
	if (AActor::bUsePercentageBasedScaling)
	{
		if (ModifiedScale.X == -1)
		{
			ModifiedScale.X = ModifiedScale.Y = -(CurrentScale.X - 1) / CurrentScale.X;
		}
		if (ModifiedScale.Z == -1)
		{
			ModifiedScale.Z = -(CurrentScale.Z - 1) / CurrentScale.Z;
		}
	}
	else
	{
		if (ModifiedScale.X == -CurrentScale.X)
		{
			CurrentScale.X += 1;
			CurrentScale.Y += 1;
		}
		if (ModifiedScale.Z == -CurrentScale.Z)
		{
			CurrentScale.Z += 1;
		}
	}

	Super::EditorApplyScale(ModifiedScale, PivotLocation, bAltDown, bShiftDown, bCtrlDown);

	// We need to regenerate collision objects, they depend on scale value 
	for (ULandscapeHeightfieldCollisionComponent* Comp : CollisionComponents)
	{
		if (Comp)
		{
			Comp->RecreateCollision(false);
		}
	}
}

void ALandscapeProxy::EditorApplyMirror(const FVector& MirrorScale, const FVector& PivotLocation)
{
	Super::EditorApplyMirror(MirrorScale, PivotLocation);

	// We need to regenerate collision objects, they depend on scale value 
	for (ULandscapeHeightfieldCollisionComponent* Comp : CollisionComponents)
	{
		if (Comp)
		{
			Comp->RecreateCollision(false);
		}
	}
}

void ALandscapeProxy::PostEditMove(bool bFinished)
{
	// This point is only reached when Copy and Pasted
	Super::PostEditMove(bFinished);

	if (bFinished)
	{
		ULandscapeInfo::RecreateLandscapeInfo(GetWorld(), true);
		RecreateComponentsState();

		if (SplineComponent)
		{
			SplineComponent->CheckSplinesValid();
		}
	}
}

void ALandscapeProxy::PostEditImport()
{
	Super::PostEditImport();
	if (!bIsProxy && GetWorld()) // For Landscape
	{
		for (TActorIterator<ALandscape> It(GetWorld()); It; ++It)
		{
			ALandscape* Landscape = *It;
			if (Landscape != this && !Landscape->HasAnyFlags(RF_BeginDestroyed) && Landscape->LandscapeGuid == LandscapeGuid)
			{
				// Copy/Paste case, need to generate new GUID
				LandscapeGuid = FGuid::NewGuid();
			}
		}
	}

	for (int32 ComponentIndex = 0; ComponentIndex < LandscapeComponents.Num(); ++ComponentIndex)
	{
		ULandscapeComponent* Comp = LandscapeComponents[ComponentIndex];
		if (Comp)
		{
			// Update the MIC
			Comp->UpdateMaterialInstances();
		}
	}

	GEngine->DeferredCommands.AddUnique(TEXT("UpdateLandscapeEditorData"));
}

void ALandscape::PostEditMove(bool bFinished)
{
	if (bFinished)
	{
		// align all proxies to landscape actor
		GetLandscapeInfo()->FixupProxiesTransform();
	}

	Super::PostEditMove(bFinished);
}
#endif	//WITH_EDITOR

ULandscapeLayerInfoObject::ULandscapeLayerInfoObject(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
	Hardness = 0.5f;
#if WITH_EDITORONLY_DATA
	bNoWeightBlend = false;
#endif // WITH_EDITORONLY_DATA
}

#if WITH_EDITOR
void ULandscapeLayerInfoObject::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	static const FName NAME_Hardness = FName(TEXT("Hardness"));
	static const FName NAME_PhysMaterial = FName(TEXT("PhysMaterial"));

	Super::PostEditChangeProperty(PropertyChangedEvent);

	const FName PropertyName = PropertyChangedEvent.Property ? PropertyChangedEvent.Property->GetFName() : NAME_None;

	if (GIsEditor)
	{
		if (PropertyName == NAME_Hardness)
		{
			Hardness = FMath::Clamp<float>(Hardness, 0.0f, 1.0f);
		}
		else if (PropertyName == NAME_PhysMaterial)
		{
			// Only care current world object
			for (TActorIterator<ALandscapeProxy> It(GWorld); It; ++It)
			{
				ALandscapeProxy* Proxy = *It;
				ULandscapeInfo* Info = Proxy->GetLandscapeInfo(false);
				if (Info)
				{
					for (int32 i = 0; i < Info->Layers.Num(); ++i)
					{
						if (Info->Layers[i].LayerInfoObj == this)
						{
							Proxy->ChangedPhysMaterial();
							break;
						}
					}
				}
			}
		}
	}
}

void ULandscapeLayerInfoObject::PostLoad()
{
	Super::PostLoad();
	if (GIsEditor)
	{
		if (!HasAnyFlags(RF_Standalone))
		{
			SetFlags(RF_Standalone);
		}
		Hardness = FMath::Clamp<float>(Hardness, 0.0f, 1.0f);
	}
}

void ALandscapeProxy::RemoveXYOffsets()
{
	bool bFoundXYOffset = false;

	for (int32 i = 0; i < LandscapeComponents.Num(); ++i)
	{
		ULandscapeComponent* Comp = LandscapeComponents[i];
		if (Comp && Comp->XYOffsetmapTexture)
		{
			Comp->XYOffsetmapTexture->SetFlags(RF_Transactional);
			Comp->XYOffsetmapTexture->Modify();
			Comp->XYOffsetmapTexture->MarkPackageDirty();
			Comp->XYOffsetmapTexture->ClearFlags(RF_Standalone);
			Comp->Modify();
			Comp->MarkPackageDirty();
			Comp->XYOffsetmapTexture = NULL;
			Comp->MarkRenderStateDirty();
			bFoundXYOffset = true;
		}
	}

	if (bFoundXYOffset)
	{
		RecreateCollisionComponents();
	}
}

void ALandscapeProxy::RecreateCollisionComponents()
{
	// We can assume these are all junk; they recreate as needed
	FlushGrassComponents();

	// Clear old CollisionComponent containers
	CollisionComponents.Empty();

	// Destroy any owned collision components
	TInlineComponentArray<ULandscapeHeightfieldCollisionComponent*> CollisionComps;
	GetComponents(CollisionComps);
	for (ULandscapeHeightfieldCollisionComponent* Component : CollisionComps)
	{
		Component->DestroyComponent();
	}

	TArray<USceneComponent*> AttachedCollisionComponents = RootComponent->AttachChildren.FilterByPredicate(
		[](USceneComponent* Component)
	{
		return Cast<ULandscapeHeightfieldCollisionComponent>(Component);
	});

	// Destroy any attached but un-owned collision components
	for (USceneComponent* Component : AttachedCollisionComponents)
	{
		Component->DestroyComponent();
	}

	// Recreate collision
	CollisionMipLevel = FMath::Clamp<int32>(CollisionMipLevel, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
	for (int32 i = 0; i < LandscapeComponents.Num(); ++i)
	{
		ULandscapeComponent* Comp = LandscapeComponents[i];
		if (Comp)
		{
			Comp->CollisionMipLevel = CollisionMipLevel;
			TArray<uint8> CollisionMipData;
			Comp->HeightmapTexture->Source.GetMipData(CollisionMipData, CollisionMipLevel);
			Comp->UpdateCollisionHeightData((FColor*)CollisionMipData.GetData(), 0, 0, MAX_int32, MAX_int32, true, NULL, true); // Rebuild for new CollisionMipLevel
		}
	}
}

void ULandscapeInfo::RecreateCollisionComponents()
{
	if (LandscapeActor.IsValid())
	{
		LandscapeActor->RecreateCollisionComponents();
	}

	for (auto It = Proxies.CreateConstIterator(); It; ++It)
	{
		ALandscapeProxy* Proxy = (*It);
		Proxy->RecreateCollisionComponents();
	}
}

void ULandscapeInfo::RemoveXYOffsets()
{
	if (LandscapeActor.IsValid())
	{
		LandscapeActor->RemoveXYOffsets();
	}

	for (auto It = Proxies.CreateConstIterator(); It; ++It)
	{
		ALandscapeProxy* Proxy = (*It);
		Proxy->RemoveXYOffsets();
	}
}

void ULandscapeInfo::PostponeTextureBaking()
{
	const int32 PostponeValue = 60; //frames
	
	ALandscape* Landscape = LandscapeActor.Get();
	if (Landscape)
	{
		Landscape->UpdateBakedTexturesCountdown = PostponeValue;
	}

	for (ALandscapeProxy* Proxy : Proxies)
	{
		Proxy->UpdateBakedTexturesCountdown = PostponeValue;
	}
}

namespace
{
	inline float AdjustStaticLightingResolution(float StaticLightingResolution, int32 NumSubsections, int32 SubsectionSizeQuads, int32 ComponentSizeQuads)
	{
		// Change Lighting resolution to proper one...
		if (StaticLightingResolution > 1.0f)
		{
			StaticLightingResolution = (int32)StaticLightingResolution;
		}
		else if (StaticLightingResolution < 1.0f)
		{
			// Restrict to 1/16
			if (StaticLightingResolution < 0.0625)
			{
				StaticLightingResolution = 0.0625;
			}

			// Adjust to 1/2^n
			int32 i = 2;
			int32 LightmapSize = (NumSubsections * (SubsectionSizeQuads + 1)) >> 1;
			while (StaticLightingResolution < (1.0f / i) && LightmapSize > 4)
			{
				i <<= 1;
				LightmapSize >>= 1;
			}
			StaticLightingResolution = 1.0f / i;

			int32 PixelPaddingX = GPixelFormats[PF_DXT1].BlockSizeX;

			int32 DestSize = (int32)((2 * PixelPaddingX + ComponentSizeQuads + 1) * StaticLightingResolution);
			StaticLightingResolution = (float)DestSize / (2 * PixelPaddingX + ComponentSizeQuads + 1);
		}

		return StaticLightingResolution;
	}
};

void ALandscapeProxy::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	Super::PostEditChangeProperty(PropertyChangedEvent);
	const FName PropertyName = PropertyChangedEvent.MemberProperty ? PropertyChangedEvent.MemberProperty->GetFName() : NAME_None;
	if (bIsProxy)
	{
		if (PropertyName == FName(TEXT("LandscapeActor")))
		{
			if (LandscapeActor && IsValidLandscapeActor(LandscapeActor.Get()))
			{
				LandscapeGuid = LandscapeActor->LandscapeGuid;
				// defer LandscapeInfo setup
				if (GIsEditor && GetWorld() && !GetWorld()->IsPlayInEditor())
				{
					GEngine->DeferredCommands.AddUnique(TEXT("UpdateLandscapeEditorData"));
				}
			}
			else
			{
				LandscapeActor = nullptr;
			}
		}
		else if (PropertyName == FName(TEXT("LandscapeMaterial")) || PropertyName == FName(TEXT("LandscapeHoleMaterial")))
		{
			FMaterialUpdateContext MaterialUpdateContext;
			GetLandscapeInfo()->UpdateLayerInfoMap(/*this*/);

			// Clear the parents out of combination material instances
			for (TMap<FString, UMaterialInstanceConstant*>::TIterator It(MaterialInstanceConstantMap); It; ++It)
			{
				It.Value()->SetParentEditorOnly(NULL);
				MaterialUpdateContext.AddMaterial(It.Value()->GetMaterial());
			}

			// Remove our references to any material instances
			MaterialInstanceConstantMap.Empty();

			for (int32 ComponentIndex = 0; ComponentIndex < LandscapeComponents.Num(); ComponentIndex++)
			{
				ULandscapeComponent* Comp = LandscapeComponents[ComponentIndex];
				if (Comp)
				{
					// Update the MIC
					Comp->UpdateMaterialInstances();
				}
			}
		}
	}

	if (GIsEditor && PropertyName == FName(TEXT("StreamingDistanceMultiplier")))
	{
		// Recalculate in a few seconds.
		GetWorld()->TriggerStreamingDataRebuild();
	}
	else if (GIsEditor && PropertyName == FName(TEXT("DefaultPhysMaterial")))
	{
		ChangedPhysMaterial();
	}
	else if (GIsEditor && (PropertyName == FName(TEXT("CollisionMipLevel"))))
	{
		RecreateCollisionComponents();
	}
	else 
		if(PropertyName == FName(TEXT("bCastStaticShadow"))
		|| PropertyName == FName(TEXT("bCastShadowAsTwoSided"))
		|| PropertyName == FName(TEXT("bCastFarShadow"))
		)
	{
		// Replicate shared properties to all components.
		for (int32 ComponentIndex = 0; ComponentIndex < LandscapeComponents.Num(); ComponentIndex++)
		{
			ULandscapeComponent* Comp = LandscapeComponents[ComponentIndex];
			if (Comp)
			{
				Comp->bCastStaticShadow = bCastStaticShadow;
				Comp->bCastShadowAsTwoSided = bCastShadowAsTwoSided;
				Comp->bCastFarShadow = bCastFarShadow;
			}
		}
	}
}

void ALandscapeProxy::PostEditChangeChainProperty(FPropertyChangedChainEvent& PropertyChangedEvent)
{
	const FName MemberPropertyName = PropertyChangedEvent.PropertyChain.GetActiveMemberNode()->GetValue()->GetFName();
	const FName PropertyName = PropertyChangedEvent.PropertyChain.GetActiveNode()->GetValue()->GetFName();

	if (MemberPropertyName == FName(TEXT("RelativeScale3D")))
	{
		// RelativeScale3D isn't even a property of ALandscapeProxy, it's a property of the root component
		if (RootComponent)
		{
			FVector ModifiedScale = RootComponent->RelativeScale3D;

			// Lock X and Y scaling to the same value
			if (PropertyName == FName("Y"))
			{
				ModifiedScale.X = FMath::Abs(RootComponent->RelativeScale3D.Y)*FMath::Sign(ModifiedScale.X);
			}
			else
			{
				// There's no "if name == X" here so that if we can't tell which has changed out of X and Y, we just use X
				ModifiedScale.Y = FMath::Abs(RootComponent->RelativeScale3D.X)*FMath::Sign(ModifiedScale.Y);
			}

			ULandscapeInfo* Info = GetLandscapeInfo(false);

			// Correct for attempts to scale to 0 on any axis
			if (ModifiedScale.X == 0)
			{
				if (Info && Info->DrawScale.X < 0)
				{
					ModifiedScale.Y = ModifiedScale.X = -1;
				}
				else
				{
					ModifiedScale.Y = ModifiedScale.X = 1;
				}
			}
			if (ModifiedScale.Z == 0)
			{
				if (Info && Info->DrawScale.Z < 0)
				{
					ModifiedScale.Z = -1;
				}
				else
				{
					ModifiedScale.Z = 1;
				}
			}

			RootComponent->SetRelativeScale3D(ModifiedScale);

			// Update ULandscapeInfo cached DrawScale
			if (Info)
			{
				Info->DrawScale = ModifiedScale;
			}

			// We need to regenerate collision objects, they depend on scale value 
			for (int32 ComponentIndex = 0; ComponentIndex < CollisionComponents.Num(); ComponentIndex++)
			{
				ULandscapeHeightfieldCollisionComponent* Comp = CollisionComponents[ComponentIndex];
				if (Comp)
				{
					Comp->RecreateCollision(false);
				}
			}
		}
	}

	// Must do this *after* correcting the scale or reattaching the landscape components will crash!
	Super::PostEditChangeChainProperty(PropertyChangedEvent);
}

void ALandscape::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	Super::PostEditChangeProperty(PropertyChangedEvent);

	const FName PropertyName = PropertyChangedEvent.Property ? PropertyChangedEvent.Property->GetFName() : NAME_None;

	bool ChangedMaterial = false;
	bool bNeedsRecalcBoundingBox = false;
	bool bChangedLighting = false;
	bool bChangedNavRelevance = false;
	bool bPropagateToProxies = false;

	ULandscapeInfo* Info = GetLandscapeInfo();

	if (PropertyName == FName(TEXT("LandscapeMaterial")) || PropertyName == FName(TEXT("LandscapeHoleMaterial")))
	{
		FMaterialUpdateContext MaterialUpdateContext;
		GetLandscapeInfo()->UpdateLayerInfoMap(/*this*/);

		ChangedMaterial = true;

		// Clear the parents out of combination material instances
		for (TMap<FString, UMaterialInstanceConstant*>::TIterator It(MaterialInstanceConstantMap); It; ++It)
		{
			It.Value()->SetParentEditorOnly(NULL);
			MaterialUpdateContext.AddMaterial(It.Value()->GetMaterial());
		}

		// Remove our references to any material instances
		MaterialInstanceConstantMap.Empty();
	}
	else if (PropertyName == FName(TEXT("RelativeScale3D")) ||
		PropertyName == FName(TEXT("RelativeLocation")) ||
		PropertyName == FName(TEXT("RelativeRotation")))
	{
		// update transformations for all linked proxies 
		Info->FixupProxiesTransform();
		bNeedsRecalcBoundingBox = true;
	}
	else if (GIsEditor && PropertyName == FName(TEXT("MaxLODLevel")))
	{
		MaxLODLevel = FMath::Clamp<int32>(MaxLODLevel, -1, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
		bPropagateToProxies = true;
	}
	else if (PropertyName == FName(TEXT("LODDistanceFactor")))
	{
		LODDistanceFactor = FMath::Clamp<float>(LODDistanceFactor, 0.1f, MAX_LANDSCAPE_LOD_DISTANCE_FACTOR); // limit because LOD transition became too popping...
		bPropagateToProxies = true;
	}
	else if (PropertyName == FName(TEXT("CollisionMipLevel")))
	{
		CollisionMipLevel = FMath::Clamp<int32>(CollisionMipLevel, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
		bPropagateToProxies = true;
	}
	else if (PropertyName == FName(TEXT("LODFalloff")))
	{
		bPropagateToProxies = true;
	}
	else if (GIsEditor && PropertyName == FName(TEXT("StaticLightingResolution")))
	{
		StaticLightingResolution = ::AdjustStaticLightingResolution(StaticLightingResolution, NumSubsections, SubsectionSizeQuads, ComponentSizeQuads);
		bChangedLighting = true;
	}
	else if (GIsEditor && PropertyName == GET_MEMBER_NAME_CHECKED(ALandscapeProxy, StaticLightingLOD))
	{
		StaticLightingLOD = FMath::Clamp<int32>(StaticLightingLOD, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
		bChangedLighting = true;
	}
	else if (GIsEditor && PropertyName == GET_MEMBER_NAME_CHECKED(ALandscapeProxy, ExportLOD))
	{
		ExportLOD = FMath::Clamp<int32>(ExportLOD, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
	}
	else if (GIsEditor && PropertyName == GET_MEMBER_NAME_CHECKED(ALandscapeProxy, bUsedForNavigation))
	{
		bChangedNavRelevance = true;
	}

	bPropagateToProxies = bPropagateToProxies || bNeedsRecalcBoundingBox || bChangedLighting;

	if (Info)
	{
		if (bPropagateToProxies)
		{
			// Propagate Event to Proxies...
			for (TSet<ALandscapeProxy*>::TIterator It(Info->Proxies); It; ++It)
			{
				(*It)->GetSharedProperties(this);
				(*It)->PostEditChangeProperty(PropertyChangedEvent);
			}
		}

		// Update normals if DrawScale3D is changed
		if (PropertyName == FName(TEXT("RelativeScale3D")))
		{
			FLandscapeEditDataInterface LandscapeEdit(Info);
			LandscapeEdit.RecalculateNormals();
		}

		TArray<ULandscapeComponent*> AllComponents;
		Info->XYtoComponentMap.GenerateValueArray(AllComponents);

		// We cannot iterate the XYtoComponentMap directly because reregistering components modifies the array.
		for (auto It = AllComponents.CreateIterator(); It; ++It)
		{
			ULandscapeComponent* Comp = *It;
			if (Comp)
			{
				if (bNeedsRecalcBoundingBox)
				{
					Comp->UpdateCachedBounds();
					Comp->UpdateBounds();
				}

				if (ChangedMaterial)
				{
					// Update the MIC
					Comp->UpdateMaterialInstances();
				}

				if (bChangedLighting)
				{
					Comp->InvalidateLightingCache();
				}

				if (bChangedNavRelevance)
				{
					Comp->UpdateNavigationRelevance();
				}

				// Reattach all components
				FComponentReregisterContext ReregisterContext(Comp);
			}
		}

		// Need to update Gizmo scene proxy
		if (bNeedsRecalcBoundingBox && GetWorld())
		{
			for (TActorIterator<ALandscapeGizmoActiveActor> It(GetWorld()); It; ++It)
			{
				It->ReregisterAllComponents();
			}
		}

		if (ChangedMaterial)
		{
			if (GIsEditor && GetWorld() && !GetWorld()->IsPlayInEditor())
			{
				GEngine->DeferredCommands.AddUnique(TEXT("UpdateLandscapeMIC"));
			}

			// Update all the proxies...
			for (TSet<ALandscapeProxy*>::TIterator It(Info->Proxies); It; ++It)
			{
				(*It)->MarkComponentsRenderStateDirty();
			}
		}
	}
}

void ALandscapeProxy::ChangedPhysMaterial()
{
	ULandscapeInfo* LandscapeInfo = GetLandscapeInfo();
	if (!LandscapeInfo) return;
	for (auto It = LandscapeInfo->XYtoComponentMap.CreateIterator(); It; ++It)
	{
		ULandscapeComponent* Comp = It.Value();
		if (Comp)
		{
			ULandscapeHeightfieldCollisionComponent* CollisionComponent = Comp->CollisionComponent.Get();
			if (CollisionComponent)
			{
				Comp->UpdateCollisionLayerData();
				// Physical materials cooked into collision object, so we need to recreate it
				CollisionComponent->RecreateCollision(false);
			}
		}
	}
}

void ULandscapeComponent::SetLOD(bool bForcedLODChanged, int32 InLODValue)
{
	if (bForcedLODChanged)
	{
		ForcedLOD = InLODValue;
		if (ForcedLOD >= 0)
		{
			ForcedLOD = FMath::Clamp<int32>(ForcedLOD, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
		}
		else
		{
			ForcedLOD = -1;
		}
	}
	else
	{
		int32 MaxLOD = FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1;
		LODBias = FMath::Clamp<int32>(InLODValue, -MaxLOD, MaxLOD);
	}

	InvalidateLightingCache();

	// Update neighbor components
	ULandscapeInfo* Info = GetLandscapeInfo(false);
	if (Info)
	{
		FIntPoint ComponentBase = GetSectionBase() / ComponentSizeQuads;
		FIntPoint LandscapeKey[8] =
		{
			ComponentBase + FIntPoint(-1, -1),
			ComponentBase + FIntPoint(+0, -1),
			ComponentBase + FIntPoint(+1, -1),
			ComponentBase + FIntPoint(-1, +0),
			ComponentBase + FIntPoint(+1, +0),
			ComponentBase + FIntPoint(-1, +1),
			ComponentBase + FIntPoint(+0, +1),
			ComponentBase + FIntPoint(+1, +1)
		};

		for (int32 Idx = 0; Idx < 8; ++Idx)
		{
			ULandscapeComponent* Comp = Info->XYtoComponentMap.FindRef(LandscapeKey[Idx]);
			if (Comp)
			{
				Comp->Modify();
				Comp->InvalidateLightingCache();
				FComponentReregisterContext ReregisterContext(Comp);
			}
		}
	}
	FComponentReregisterContext ReregisterContext(this);
}

void ULandscapeComponent::PreEditChange(UProperty* PropertyThatWillChange)
{
	Super::PreEditChange(PropertyThatWillChange);
	if (GIsEditor && PropertyThatWillChange && (PropertyThatWillChange->GetFName() == GET_MEMBER_NAME_CHECKED(ULandscapeComponent, ForcedLOD) || PropertyThatWillChange->GetFName() == GET_MEMBER_NAME_CHECKED(ULandscapeComponent, LODBias)))
	{
		// PreEdit unregister component and re-register after PostEdit so we will lose XYtoComponentMap for this component
		ULandscapeInfo* Info = GetLandscapeInfo(false);
		if (Info)
		{
			FIntPoint ComponentKey = GetSectionBase() / ComponentSizeQuads;
			auto RegisteredComponent = Info->XYtoComponentMap.FindRef(ComponentKey);

			if (RegisteredComponent == NULL)
			{
				Info->XYtoComponentMap.Add(ComponentKey, this);
			}
		}
	}
}

void ULandscapeComponent::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	Super::PostEditChangeProperty(PropertyChangedEvent);

	const FName PropertyName = PropertyChangedEvent.Property ? PropertyChangedEvent.Property->GetFName() : NAME_None;
	if (PropertyName == FName(TEXT("OverrideMaterial")))
	{
		UpdateMaterialInstances();
		// Reregister all components
		FComponentReregisterContext ReregisterContext(this);
	}
	else if (GIsEditor && (PropertyName == FName(TEXT("ForcedLOD")) || PropertyName == FName(TEXT("LODBias"))))
	{
		bool bForcedLODChanged = PropertyName == FName(TEXT("ForcedLOD"));
		SetLOD(bForcedLODChanged, bForcedLODChanged ? ForcedLOD : LODBias);
	}
	else if (GIsEditor && PropertyName == FName(TEXT("StaticLightingResolution")))
	{
		if (StaticLightingResolution > 0.0f)
		{
			StaticLightingResolution = ::AdjustStaticLightingResolution(StaticLightingResolution, NumSubsections, SubsectionSizeQuads, ComponentSizeQuads);
		}
		else
		{
			StaticLightingResolution = 0;
		}
		InvalidateLightingCache();
	}
	else if (GIsEditor && PropertyName == FName(TEXT("LightingLODBias")))
	{
		int32 MaxLOD = FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1;
		LightingLODBias = FMath::Clamp<int32>(LightingLODBias, -1, MaxLOD);
		InvalidateLightingCache();
	}
	else if (GIsEditor && (PropertyName == FName(TEXT("CollisionMipLevel"))))
	{
		CollisionMipLevel = FMath::Clamp<int32>(CollisionMipLevel, 0, FMath::CeilLogTwo(SubsectionSizeQuads + 1) - 1);
		TArray<uint8> CollisionMipData;
		HeightmapTexture->Source.GetMipData(CollisionMipData, CollisionMipLevel);
		UpdateCollisionHeightData((FColor*)CollisionMipData.GetData(), 0, 0, MAX_int32, MAX_int32, true, NULL, true); // Rebuild for new CollisionMipLevel
	}
}

TSet<class ULandscapeComponent*> ULandscapeInfo::GetSelectedComponents() const
{
	return SelectedComponents;
}

TSet<class ULandscapeComponent*> ULandscapeInfo::GetSelectedRegionComponents() const
{
	return SelectedRegionComponents;
}

void ULandscapeInfo::UpdateSelectedComponents(TSet<ULandscapeComponent*>& NewComponents, bool bIsComponentwise /*=true*/)
{
	int32 InSelectType = bIsComponentwise ? FLandscapeEditToolRenderData::ST_COMPONENT : FLandscapeEditToolRenderData::ST_REGION;

	if (bIsComponentwise)
	{
		for (TSet<ULandscapeComponent*>::TIterator It(NewComponents); It; ++It)
		{
			ULandscapeComponent* Comp = *It;
			if (Comp->EditToolRenderData != NULL && (Comp->EditToolRenderData->SelectedType & InSelectType) == 0)
			{
				Comp->Modify();
				int32 SelectedType = Comp->EditToolRenderData->SelectedType;
				SelectedType |= InSelectType;
				Comp->EditToolRenderData->UpdateSelectionMaterial(SelectedType);
			}
		}

		// Remove the material from any old components that are no longer in the region
		TSet<ULandscapeComponent*> RemovedComponents = SelectedComponents.Difference(NewComponents);
		for (TSet<ULandscapeComponent*>::TIterator It(RemovedComponents); It; ++It)
		{
			ULandscapeComponent* Comp = *It;
			if (Comp->EditToolRenderData != NULL)
			{
				Comp->Modify();
				int32 SelectedType = Comp->EditToolRenderData->SelectedType;
				SelectedType &= ~InSelectType;
				Comp->EditToolRenderData->UpdateSelectionMaterial(SelectedType);
			}
		}
		SelectedComponents = NewComponents;
	}
	else
	{
		// Only add components...
		if (NewComponents.Num())
		{
			for (TSet<ULandscapeComponent*>::TIterator It(NewComponents); It; ++It)
			{
				ULandscapeComponent* Comp = *It;
				if (Comp->EditToolRenderData != NULL && (Comp->EditToolRenderData->SelectedType & InSelectType) == 0)
				{
					Comp->Modify();
					int32 SelectedType = Comp->EditToolRenderData->SelectedType;
					SelectedType |= InSelectType;
					Comp->EditToolRenderData->UpdateSelectionMaterial(SelectedType);
				}

				SelectedRegionComponents.Add(*It);
			}
		}
		else
		{
			// Remove the material from any old components that are no longer in the region
			for (TSet<ULandscapeComponent*>::TIterator It(SelectedRegionComponents); It; ++It)
			{
				ULandscapeComponent* Comp = *It;
				if (Comp->EditToolRenderData != NULL)
				{
					Comp->Modify();
					int32 SelectedType = Comp->EditToolRenderData->SelectedType;
					SelectedType &= ~InSelectType;
					Comp->EditToolRenderData->UpdateSelectionMaterial(SelectedType);
				}
			}
			SelectedRegionComponents = NewComponents;
		}
	}
}

void ULandscapeInfo::SortSelectedComponents()
{
	struct FCompareULandscapeComponentBySectionBase
	{
		FORCEINLINE bool operator()(const ULandscapeComponent& A, const ULandscapeComponent& B) const
		{
			return (A.GetSectionBase().X == B.GetSectionBase().X) ? (A.GetSectionBase().Y < B.GetSectionBase().Y) : (A.GetSectionBase().X < B.GetSectionBase().X);
		}
	};
	SelectedComponents.Sort(FCompareULandscapeComponentBySectionBase());
}

void ULandscapeInfo::ClearSelectedRegion(bool bIsComponentwise /*= true*/)
{
	TSet<ULandscapeComponent*> NewComponents;
	UpdateSelectedComponents(NewComponents, bIsComponentwise);
	if (!bIsComponentwise)
	{
		SelectedRegion.Empty();
	}
}

struct FLandscapeDataInterface* ULandscapeInfo::GetDataInterface()
{
	if (DataInterface == NULL)
	{
		DataInterface = new FLandscapeDataInterface();
	}

	return DataInterface;
}

void ULandscapeComponent::ReallocateWeightmaps(FLandscapeEditDataInterface* DataInterface)
{
	ALandscapeProxy* Proxy = GetLandscapeProxy();

	int32 NeededNewChannels = 0;
	for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
	{
		if (WeightmapLayerAllocations[LayerIdx].WeightmapTextureIndex == 255)
		{
			NeededNewChannels++;
		}
	}

	// All channels allocated!
	if (NeededNewChannels == 0)
	{
		return;
	}

	Modify();
	//Landscape->Modify();
	Proxy->Modify();

	// UE_LOG(LogLandscape, Log, TEXT("----------------------"));
	// UE_LOG(LogLandscape, Log, TEXT("Component %s needs %d layers (%d new)"), *GetName(), WeightmapLayerAllocations.Num(), NeededNewChannels);

	// See if our existing textures have sufficient space
	int32 ExistingTexAvailableChannels = 0;
	for (int32 TexIdx = 0; TexIdx < WeightmapTextures.Num(); TexIdx++)
	{
		FLandscapeWeightmapUsage* Usage = Proxy->WeightmapUsageMap.Find(WeightmapTextures[TexIdx]);
		check(Usage);

		ExistingTexAvailableChannels += Usage->FreeChannelCount();

		if (ExistingTexAvailableChannels >= NeededNewChannels)
		{
			break;
		}
	}

	if (ExistingTexAvailableChannels >= NeededNewChannels)
	{
		// UE_LOG(LogLandscape, Log, TEXT("Existing texture has available channels"));

		// Allocate using our existing textures' spare channels.
		for (int32 TexIdx = 0; TexIdx < WeightmapTextures.Num(); TexIdx++)
		{
			FLandscapeWeightmapUsage* Usage = Proxy->WeightmapUsageMap.Find(WeightmapTextures[TexIdx]);

			for (int32 ChanIdx = 0; ChanIdx < 4; ChanIdx++)
			{
				if (Usage->ChannelUsage[ChanIdx] == NULL)
				{
					for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
					{
						FWeightmapLayerAllocationInfo& AllocInfo = WeightmapLayerAllocations[LayerIdx];
						if (AllocInfo.WeightmapTextureIndex == 255)
						{
							// Zero out the data for this texture channel
							if (DataInterface)
							{
								DataInterface->ZeroTextureChannel(WeightmapTextures[TexIdx], ChanIdx);
							}

							AllocInfo.WeightmapTextureIndex = TexIdx;
							AllocInfo.WeightmapTextureChannel = ChanIdx;
							Usage->ChannelUsage[ChanIdx] = this;
							NeededNewChannels--;

							if (NeededNewChannels == 0)
							{
								return;
							}
						}
					}
				}
			}
		}
		// we should never get here.
		check(false);
	}

	// UE_LOG(LogLandscape, Log, TEXT("Reallocating."));

	// We are totally reallocating the weightmap
	int32 TotalNeededChannels = WeightmapLayerAllocations.Num();
	int32 CurrentLayer = 0;
	TArray<UTexture2D*> NewWeightmapTextures;
	while (TotalNeededChannels > 0)
	{
		// UE_LOG(LogLandscape, Log, TEXT("Still need %d channels"), TotalNeededChannels);

		UTexture2D* CurrentWeightmapTexture = NULL;
		FLandscapeWeightmapUsage* CurrentWeightmapUsage = NULL;

		if (TotalNeededChannels < 4)
		{
			// UE_LOG(LogLandscape, Log, TEXT("Looking for nearest"));

			// see if we can find a suitable existing weightmap texture with sufficient channels
			int32 BestDistanceSquared = MAX_int32;
			for (TMap<UTexture2D*, struct FLandscapeWeightmapUsage>::TIterator It(Proxy->WeightmapUsageMap); It; ++It)
			{
				FLandscapeWeightmapUsage* TryWeightmapUsage = &It.Value();
				if (TryWeightmapUsage->FreeChannelCount() >= TotalNeededChannels)
				{
					// See if this candidate is closer than any others we've found
					for (int32 ChanIdx = 0; ChanIdx < 4; ChanIdx++)
					{
						if (TryWeightmapUsage->ChannelUsage[ChanIdx] != NULL)
						{
							int32 TryDistanceSquared = (TryWeightmapUsage->ChannelUsage[ChanIdx]->GetSectionBase() - GetSectionBase()).SizeSquared();
							if (TryDistanceSquared < BestDistanceSquared)
							{
								CurrentWeightmapTexture = It.Key();
								CurrentWeightmapUsage = TryWeightmapUsage;
								BestDistanceSquared = TryDistanceSquared;
							}
						}
					}
				}
			}
		}

		bool NeedsUpdateResource = false;
		// No suitable weightmap texture
		if (CurrentWeightmapTexture == NULL)
		{
			MarkPackageDirty();

			// Weightmap is sized the same as the component
			int32 WeightmapSize = (SubsectionSizeQuads + 1) * NumSubsections;

			// We need a new weightmap texture
			CurrentWeightmapTexture = GetLandscapeProxy()->CreateLandscapeTexture(WeightmapSize, WeightmapSize, TEXTUREGROUP_Terrain_Weightmap, TSF_BGRA8);
			// Alloc dummy mips
			CreateEmptyTextureMips(CurrentWeightmapTexture);
			CurrentWeightmapTexture->PostEditChange();

			// Store it in the usage map
			CurrentWeightmapUsage = &Proxy->WeightmapUsageMap.Add(CurrentWeightmapTexture, FLandscapeWeightmapUsage());

			// UE_LOG(LogLandscape, Log, TEXT("Making a new texture %s"), *CurrentWeightmapTexture->GetName());
		}

		NewWeightmapTextures.Add(CurrentWeightmapTexture);

		for (int32 ChanIdx = 0; ChanIdx < 4 && TotalNeededChannels > 0; ChanIdx++)
		{
			// UE_LOG(LogLandscape, Log, TEXT("Finding allocation for layer %d"), CurrentLayer);

			if (CurrentWeightmapUsage->ChannelUsage[ChanIdx] == NULL)
			{
				// Use this allocation
				FWeightmapLayerAllocationInfo& AllocInfo = WeightmapLayerAllocations[CurrentLayer];

				if (AllocInfo.WeightmapTextureIndex == 255)
				{
					// New layer - zero out the data for this texture channel
					if (DataInterface)
					{
						DataInterface->ZeroTextureChannel(CurrentWeightmapTexture, ChanIdx);
						// UE_LOG(LogLandscape, Log, TEXT("Zeroing out channel %s.%d"), *CurrentWeightmapTexture->GetName(), ChanIdx);
					}
				}
				else
				{
					UTexture2D* OldWeightmapTexture = WeightmapTextures[AllocInfo.WeightmapTextureIndex];

					// Copy the data
					if (ensure(DataInterface != NULL)) // it's not safe to skip the copy
					{
						DataInterface->CopyTextureChannel(CurrentWeightmapTexture, ChanIdx, OldWeightmapTexture, AllocInfo.WeightmapTextureChannel);
						DataInterface->ZeroTextureChannel(OldWeightmapTexture, AllocInfo.WeightmapTextureChannel);
						// UE_LOG(LogLandscape, Log, TEXT("Copying old channel (%s).%d to new channel (%s).%d"), *OldWeightmapTexture->GetName(), AllocInfo.WeightmapTextureChannel, *CurrentWeightmapTexture->GetName(), ChanIdx);
					}

					// Remove the old allocation
					FLandscapeWeightmapUsage* OldWeightmapUsage = Proxy->WeightmapUsageMap.Find(OldWeightmapTexture);
					OldWeightmapUsage->ChannelUsage[AllocInfo.WeightmapTextureChannel] = NULL;
				}

				// Assign the new allocation
				CurrentWeightmapUsage->ChannelUsage[ChanIdx] = this;
				AllocInfo.WeightmapTextureIndex = NewWeightmapTextures.Num() - 1;
				AllocInfo.WeightmapTextureChannel = ChanIdx;
				CurrentLayer++;
				TotalNeededChannels--;
			}
		}
	}

	// Replace the weightmap textures
	WeightmapTextures = MoveTemp(NewWeightmapTextures);

	if (DataInterface)
	{
		// Update the mipmaps for the textures we edited
		for (int32 Idx = 0; Idx < WeightmapTextures.Num(); Idx++)
		{
			UTexture2D* WeightmapTexture = WeightmapTextures[Idx];
			FLandscapeTextureDataInfo* WeightmapDataInfo = DataInterface->GetTextureDataInfo(WeightmapTexture);

			int32 NumMips = WeightmapTexture->Source.GetNumMips();
			TArray<FColor*> WeightmapTextureMipData;
			WeightmapTextureMipData.AddUninitialized(NumMips);
			for (int32 MipIdx = 0; MipIdx < NumMips; MipIdx++)
			{
				WeightmapTextureMipData[MipIdx] = (FColor*)WeightmapDataInfo->GetMipData(MipIdx);
			}

			ULandscapeComponent::UpdateWeightmapMips(NumSubsections, SubsectionSizeQuads, WeightmapTexture, WeightmapTextureMipData, 0, 0, MAX_int32, MAX_int32, WeightmapDataInfo);
		}
	}
}

void ALandscapeProxy::RemoveInvalidWeightmaps()
{
	if (GIsEditor)
	{
		for (TMap< UTexture2D*, struct FLandscapeWeightmapUsage >::TIterator It(WeightmapUsageMap); It; ++It)
		{
			UTexture2D* Tex = It.Key();
			FLandscapeWeightmapUsage& Usage = It.Value();
			if (Usage.FreeChannelCount() == 4) // Invalid Weight-map
			{
				if (Tex)
				{
					Tex->SetFlags(RF_Transactional);
					Tex->Modify();
					Tex->MarkPackageDirty();
					Tex->ClearFlags(RF_Standalone);
				}
				WeightmapUsageMap.Remove(Tex);
			}
		}

		// Remove Unused Weightmaps...
		for (int32 Idx = 0; Idx < LandscapeComponents.Num(); ++Idx)
		{
			ULandscapeComponent* Component = LandscapeComponents[Idx];
			Component->RemoveInvalidWeightmaps();
		}
	}
}

void ULandscapeComponent::RemoveInvalidWeightmaps()
{
	// Adjust WeightmapTextureIndex index for other layers
	TSet<int32> UsedTextureIndices;
	TSet<int32> AllTextureIndices;
	for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
	{
		UsedTextureIndices.Add(WeightmapLayerAllocations[LayerIdx].WeightmapTextureIndex);
	}

	for (int32 WeightIdx = 0; WeightIdx < WeightmapTextures.Num(); ++WeightIdx)
	{
		AllTextureIndices.Add(WeightIdx);
	}

	TSet<int32> UnUsedTextureIndices = AllTextureIndices.Difference(UsedTextureIndices);

	int32 DeletedLayers = 0;
	for (TSet<int32>::TIterator It(UnUsedTextureIndices); It; ++It)
	{
		int32 DeleteLayerWeightmapTextureIndex = *It - DeletedLayers;
		WeightmapTextures[DeleteLayerWeightmapTextureIndex]->SetFlags(RF_Transactional);
		WeightmapTextures[DeleteLayerWeightmapTextureIndex]->Modify();
		WeightmapTextures[DeleteLayerWeightmapTextureIndex]->MarkPackageDirty();
		WeightmapTextures[DeleteLayerWeightmapTextureIndex]->ClearFlags(RF_Standalone);
		WeightmapTextures.RemoveAt(DeleteLayerWeightmapTextureIndex);

		// Adjust WeightmapTextureIndex index for other layers
		for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); LayerIdx++)
		{
			FWeightmapLayerAllocationInfo& Allocation = WeightmapLayerAllocations[LayerIdx];

			if (Allocation.WeightmapTextureIndex > DeleteLayerWeightmapTextureIndex)
			{
				Allocation.WeightmapTextureIndex--;
			}

			check(Allocation.WeightmapTextureIndex < WeightmapTextures.Num());
		}
		DeletedLayers++;
	}
}

void ULandscapeComponent::InitHeightmapData(TArray<FColor>& Heights, bool bUpdateCollision)
{
	int32 ComponentSizeVerts = NumSubsections * (SubsectionSizeQuads + 1);

	if (Heights.Num() != FMath::Square(ComponentSizeVerts))
	{
		return;
	}

	// Handling old Height map....
	if (HeightmapTexture && HeightmapTexture->GetOutermost() != GetTransientPackage()
		&& HeightmapTexture->GetOutermost() == GetOutermost()
		&& HeightmapTexture->Source.GetSizeX() >= ComponentSizeVerts) // if Height map is not valid...
	{
		HeightmapTexture->SetFlags(RF_Transactional);
		HeightmapTexture->Modify();
		HeightmapTexture->MarkPackageDirty();
		HeightmapTexture->ClearFlags(RF_Standalone); // Delete if no reference...
	}

	// New Height map
	TArray<FColor*> HeightmapTextureMipData;
	// make sure the heightmap UVs are powers of two.
	int32 HeightmapSizeU = (1 << FMath::CeilLogTwo(ComponentSizeVerts));
	int32 HeightmapSizeV = (1 << FMath::CeilLogTwo(ComponentSizeVerts));

	// Height map construction
	HeightmapTexture = GetLandscapeProxy()->CreateLandscapeTexture(HeightmapSizeU, HeightmapSizeV, TEXTUREGROUP_Terrain_Heightmap, TSF_BGRA8);

	int32 MipSubsectionSizeQuads = SubsectionSizeQuads;
	int32 MipSizeU = HeightmapSizeU;
	int32 MipSizeV = HeightmapSizeV;

	HeightmapScaleBias = FVector4(1.0f / (float)HeightmapSizeU, 1.0f / (float)HeightmapSizeV, 0.0f, 0.0f);

	int32 Mip = 0;
	while (MipSizeU > 1 && MipSizeV > 1 && MipSubsectionSizeQuads >= 1)
	{
		FColor* HeightmapTextureData = (FColor*)HeightmapTexture->Source.LockMip(Mip);
		if (Mip == 0)
		{
			FMemory::Memcpy(HeightmapTextureData, Heights.GetData(), MipSizeU*MipSizeV*sizeof(FColor));
		}
		else
		{
			FMemory::Memzero(HeightmapTextureData, MipSizeU*MipSizeV*sizeof(FColor));
		}
		HeightmapTextureMipData.Add(HeightmapTextureData);

		MipSizeU >>= 1;
		MipSizeV >>= 1;
		Mip++;

		MipSubsectionSizeQuads = ((MipSubsectionSizeQuads + 1) >> 1) - 1;
	}
	ULandscapeComponent::GenerateHeightmapMips(HeightmapTextureMipData);

	if (bUpdateCollision)
	{
		ULandscapeComponent::UpdateCollisionHeightData(HeightmapTextureMipData[CollisionMipLevel]);
	}

	for (int32 i = 0; i < HeightmapTextureMipData.Num(); i++)
	{
		HeightmapTexture->Source.UnlockMip(i);
	}
	HeightmapTexture->PostEditChange();
}

void ULandscapeComponent::InitWeightmapData(TArray<ULandscapeLayerInfoObject*>& LayerInfos, TArray<TArray<uint8> >& WeightmapData)
{
	if (LayerInfos.Num() != WeightmapData.Num() || LayerInfos.Num() <= 0)
	{
		return;
	}

	int32 ComponentSizeVerts = NumSubsections * (SubsectionSizeQuads + 1);

	// Validation..
	for (int32 Idx = 0; Idx < WeightmapData.Num(); ++Idx)
	{
		if (WeightmapData[Idx].Num() != FMath::Square(ComponentSizeVerts))
		{
			return;
		}
	}

	for (int32 Idx = 0; Idx < WeightmapTextures.Num(); ++Idx)
	{
		if (WeightmapTextures[Idx] && WeightmapTextures[Idx]->GetOutermost() != GetTransientPackage()
			&& WeightmapTextures[Idx]->GetOutermost() == GetOutermost()
			&& WeightmapTextures[Idx]->Source.GetSizeX() == ComponentSizeVerts)
		{
			WeightmapTextures[Idx]->SetFlags(RF_Transactional);
			WeightmapTextures[Idx]->Modify();
			WeightmapTextures[Idx]->MarkPackageDirty();
			WeightmapTextures[Idx]->ClearFlags(RF_Standalone); // Delete if no reference...
		}
	}
	WeightmapTextures.Empty();

	WeightmapLayerAllocations.Empty(LayerInfos.Num());
	for (int32 Idx = 0; Idx < LayerInfos.Num(); ++Idx)
	{
		new (WeightmapLayerAllocations)FWeightmapLayerAllocationInfo(LayerInfos[Idx]);
	}

	ReallocateWeightmaps(NULL);

	check(WeightmapLayerAllocations.Num() > 0 && WeightmapTextures.Num() > 0);

	int32 WeightmapSize = ComponentSizeVerts;
	WeightmapScaleBias = FVector4(1.0f / (float)WeightmapSize, 1.0f / (float)WeightmapSize, 0.5f / (float)WeightmapSize, 0.5f / (float)WeightmapSize);
	WeightmapSubsectionOffset = (float)(SubsectionSizeQuads + 1) / (float)WeightmapSize;

	// Channel remapping
	int32 ChannelOffsets[4] = { (int32)STRUCT_OFFSET(FColor, R), (int32)STRUCT_OFFSET(FColor, G), (int32)STRUCT_OFFSET(FColor, B), (int32)STRUCT_OFFSET(FColor, A) };

	TArray<void*> WeightmapDataPtrs;
	WeightmapDataPtrs.AddUninitialized(WeightmapTextures.Num());
	for (int32 WeightmapIdx = 0; WeightmapIdx < WeightmapTextures.Num(); ++WeightmapIdx)
	{
		WeightmapDataPtrs[WeightmapIdx] = WeightmapTextures[WeightmapIdx]->Source.LockMip(0);
	}

	for (int32 LayerIdx = 0; LayerIdx < WeightmapLayerAllocations.Num(); ++LayerIdx)
	{
		void* DestDataPtr = WeightmapDataPtrs[WeightmapLayerAllocations[LayerIdx].WeightmapTextureIndex];
		uint8* DestTextureData = (uint8*)DestDataPtr + ChannelOffsets[WeightmapLayerAllocations[LayerIdx].WeightmapTextureChannel];
		uint8* SrcTextureData = (uint8*)&WeightmapData[LayerIdx][0];

		for (int32 i = 0; i < WeightmapData[LayerIdx].Num(); i++)
		{
			DestTextureData[i * 4] = SrcTextureData[i];
		}
	}

	for (int32 Idx = 0; Idx < WeightmapTextures.Num(); Idx++)
	{
		UTexture2D* WeightmapTexture = WeightmapTextures[Idx];
		WeightmapTexture->Source.UnlockMip(0);
	}

	for (int32 Idx = 0; Idx < WeightmapTextures.Num(); Idx++)
	{
		UTexture2D* WeightmapTexture = WeightmapTextures[Idx];
		{
			FLandscapeTextureDataInfo WeightmapDataInfo(WeightmapTexture);

			int32 NumMips = WeightmapTexture->Source.GetNumMips();
			TArray<FColor*> WeightmapTextureMipData;
			WeightmapTextureMipData.AddUninitialized(NumMips);
			for (int32 MipIdx = 0; MipIdx < NumMips; MipIdx++)
			{
				WeightmapTextureMipData[MipIdx] = (FColor*)WeightmapDataInfo.GetMipData(MipIdx);
			}

			ULandscapeComponent::UpdateWeightmapMips(NumSubsections, SubsectionSizeQuads, WeightmapTexture, WeightmapTextureMipData, 0, 0, MAX_int32, MAX_int32, &WeightmapDataInfo);
		}

		WeightmapTexture->PostEditChange();
	}

	FlushRenderingCommands();

	MaterialInstance = NULL;

}

#define MAX_LANDSCAPE_EXPORT_COMPONENTS_NUM		16
#define MAX_LANDSCAPE_PROP_TEXT_LENGTH			1024*1024*16


bool ALandscapeProxy::ShouldExport()
{
	if (!bIsMovingToLevel && LandscapeComponents.Num() > MAX_LANDSCAPE_EXPORT_COMPONENTS_NUM)
	{
		// Prompt to save startup packages
		if (EAppReturnType::Yes == FMessageDialog::Open(EAppMsgType::YesNo, FText::Format(
			NSLOCTEXT("UnrealEd", "LandscapeExport_Warning", "Landscape has large number({0}) of components, so it will use large amount memory to copy it to the clipboard. Do you want to proceed?"), FText::AsNumber(LandscapeComponents.Num()))))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	return true;
}

bool ALandscapeProxy::ShouldImport(FString* ActorPropString, bool IsMovingToLevel)
{
	bIsMovingToLevel = IsMovingToLevel;
	if (!bIsMovingToLevel && ActorPropString && ActorPropString->Len() > MAX_LANDSCAPE_PROP_TEXT_LENGTH)
	{
		// Prompt to save startup packages
		if (EAppReturnType::Yes == FMessageDialog::Open(EAppMsgType::YesNo, FText::Format(
			NSLOCTEXT("UnrealEd", "LandscapeImport_Warning", "Landscape is about to import large amount memory ({0}MB) from the clipboard, which will take some time. Do you want to proceed?"), FText::AsNumber(ActorPropString->Len() >> 20))))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	return true;
}

void ULandscapeComponent::ExportCustomProperties(FOutputDevice& Out, uint32 Indent)
{
	if (HasAnyFlags(RF_ClassDefaultObject))
	{
		return;
	}
	// Height map
	int32 NumVertices = FMath::Square(NumSubsections*(SubsectionSizeQuads + 1));
	FLandscapeComponentDataInterface DataInterface(this);
	TArray<FColor> Heightmap;
	DataInterface.GetHeightmapTextureData(Heightmap);
	check(Heightmap.Num() == NumVertices);

	Out.Logf(TEXT("%sCustomProperties LandscapeHeightData "), FCString::Spc(Indent));
	for (int32 i = 0; i < NumVertices; i++)
	{
		Out.Logf(TEXT("%x "), Heightmap[i].DWColor());
	}

	TArray<uint8> Weightmap;
	// Weight map
	Out.Logf(TEXT("LayerNum=%d "), WeightmapLayerAllocations.Num());
	for (int32 i = 0; i < WeightmapLayerAllocations.Num(); i++)
	{
		if (DataInterface.GetWeightmapTextureData(WeightmapLayerAllocations[i].LayerInfo, Weightmap))
		{
			Out.Logf(TEXT("LayerInfo=%s "), *WeightmapLayerAllocations[i].LayerInfo->GetPathName());
			for (int32 VertexIndex = 0; VertexIndex < NumVertices; VertexIndex++)
			{
				Out.Logf(TEXT("%x "), Weightmap[VertexIndex]);
			}
		}
	}

	Out.Logf(TEXT("\r\n"));
}


void ULandscapeComponent::ImportCustomProperties(const TCHAR* SourceText, FFeedbackContext* Warn)
{
	if (FParse::Command(&SourceText, TEXT("LandscapeHeightData")))
	{
		int32 NumVertices = FMath::Square(NumSubsections*(SubsectionSizeQuads + 1));

		TArray<FColor> Heights;
		Heights.Empty(NumVertices);
		Heights.AddZeroed(NumVertices);

		FParse::Next(&SourceText);
		int32 i = 0;
		TCHAR* StopStr;
		while (FChar::IsHexDigit(*SourceText))
		{
			if (i < NumVertices)
			{
				Heights[i++].DWColor() = FCString::Strtoi(SourceText, &StopStr, 16);
				while (FChar::IsHexDigit(*SourceText))
				{
					SourceText++;
				}
			}

			FParse::Next(&SourceText);
		}

		if (i != NumVertices)
		{
			Warn->Logf(*NSLOCTEXT("Core", "SyntaxError", "Syntax Error").ToString());
		}

		int32 ComponentSizeVerts = NumSubsections * (SubsectionSizeQuads + 1);

		InitHeightmapData(Heights, false);

		// Weight maps
		int32 LayerNum = 0;
		if (FParse::Value(SourceText, TEXT("LayerNum="), LayerNum))
		{
			while (*SourceText && (!FChar::IsWhitespace(*SourceText)))
			{
				++SourceText;
			}
			FParse::Next(&SourceText);
		}

		if (LayerNum <= 0)
		{
			return;
		}

		// Init memory
		TArray<ULandscapeLayerInfoObject*> LayerInfos;
		LayerInfos.Empty(LayerNum);
		TArray<TArray<uint8>> WeightmapData;
		for (int32 LayerIndex = 0; LayerIndex < LayerNum; ++LayerIndex)
		{
			TArray<uint8> Weights;
			Weights.Empty(NumVertices);
			Weights.AddUninitialized(NumVertices);
			WeightmapData.Add(Weights);
		}

		int32 LayerIdx = 0;
		FString LayerInfoPath;
		while (*SourceText)
		{
			if (FParse::Value(SourceText, TEXT("LayerInfo="), LayerInfoPath))
			{
				LayerInfos.Add(LoadObject<ULandscapeLayerInfoObject>(NULL, *LayerInfoPath));

				while (*SourceText && (!FChar::IsWhitespace(*SourceText)))
				{
					++SourceText;
				}
				FParse::Next(&SourceText);
				check(*SourceText);

				i = 0;
				while (FChar::IsHexDigit(*SourceText))
				{
					if (i < NumVertices)
					{
						(WeightmapData[LayerIdx])[i++] = (uint8)FCString::Strtoi(SourceText, &StopStr, 16);
						while (FChar::IsHexDigit(*SourceText))
						{
							SourceText++;
						}
					}
					FParse::Next(&SourceText);
				}

				if (i != NumVertices)
				{
					Warn->Logf(*NSLOCTEXT("Core", "SyntaxError", "Syntax Error").ToString());
				}
				LayerIdx++;
			}
			else
			{
				break;
			}
		}

		InitWeightmapData(LayerInfos, WeightmapData);
	}
}

bool ALandscapeProxy::IsValidLandscapeActor(ALandscape* Landscape)
{
	if (bIsProxy && Landscape)
	{
		if (!Landscape->HasAnyFlags(RF_BeginDestroyed))
		{
			if (LandscapeActor.IsNull() && !LandscapeGuid.IsValid())
			{
				return true; // always valid for newly created Proxy
			}
			if (((LandscapeActor && LandscapeActor == Landscape)
				|| (LandscapeActor.IsNull() && LandscapeGuid.IsValid() && LandscapeGuid == Landscape->LandscapeGuid))
				&& ComponentSizeQuads == Landscape->ComponentSizeQuads
				&& NumSubsections == Landscape->NumSubsections
				&& SubsectionSizeQuads == Landscape->SubsectionSizeQuads)
			{
				return true;
			}
		}
	}
	return false;
}

struct FMobileLayerAllocation
{
	FWeightmapLayerAllocationInfo Allocation;

	FMobileLayerAllocation(const FWeightmapLayerAllocationInfo& InAllocation)
		: Allocation(InAllocation)
	{
	}

	friend bool operator<(const FMobileLayerAllocation& lhs, const FMobileLayerAllocation& rhs)
	{
		if (!lhs.Allocation.LayerInfo && !rhs.Allocation.LayerInfo) return false; // equally broken :P
		if (!lhs.Allocation.LayerInfo && rhs.Allocation.LayerInfo) return false; // broken layers sort to the end
		if (!rhs.Allocation.LayerInfo && lhs.Allocation.LayerInfo) return true;

		if (lhs.Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer && rhs.Allocation.LayerInfo != ALandscapeProxy::VisibilityLayer) return true; // visibility layer to the front
		if (rhs.Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer && lhs.Allocation.LayerInfo != ALandscapeProxy::VisibilityLayer) return false;

		if (lhs.Allocation.LayerInfo->bNoWeightBlend && !rhs.Allocation.LayerInfo->bNoWeightBlend) return false; // non-blended layers sort to the end
		if (rhs.Allocation.LayerInfo->bNoWeightBlend && !lhs.Allocation.LayerInfo->bNoWeightBlend) return true;

		// TODO: If we want to support cleanly decaying a pc landscape for mobile
		// we should probably add other sort criteria, e.g. coverage
		// or e.g. add an "importance" to layerinfos and sort on that

		return false; // equal, preserve order
	}
};

void ULandscapeComponent::GeneratePlatformPixelData(bool bIsCooking)
{
	check(!IsTemplate())

	if (!bIsCooking)
	{
		// Calculate hash of source data and skip generation if the data we have in memory is unchanged
		FBufferArchive ComponentStateAr;
		SerializeStateHashes(ComponentStateAr);

		uint32 Hash[5];
		FSHA1::HashBuffer(ComponentStateAr.GetData(), ComponentStateAr.Num(), (uint8*)Hash);
		FGuid NewSourceHash = FGuid(Hash[0] ^ Hash[4], Hash[1], Hash[2], Hash[3]);
	
		// Skip generation if the source hash matches
		if (MobilePixelDataSourceHash.IsValid() && 
			MobilePixelDataSourceHash == NewSourceHash &&
			MobileMaterialInterface != nullptr &&
			MobileWeightNormalmapTexture != nullptr)
		{
			return;
		}
			
		MobilePixelDataSourceHash = NewSourceHash;
	}

	TArray<FMobileLayerAllocation> MobileLayerAllocations;
	MobileLayerAllocations.Reserve(WeightmapLayerAllocations.Num());
	for (const auto& Allocation : WeightmapLayerAllocations)
	{
		MobileLayerAllocations.Emplace(Allocation);
	}
	MobileLayerAllocations.StableSort();

	// in the current mobile shader only 3 layers are supported (the 3rd only as a blended layer)
	// so make sure we have a blended layer for layer 3 if possible
	if (MobileLayerAllocations.Num() >= 3 &&
		MobileLayerAllocations[2].Allocation.LayerInfo && MobileLayerAllocations[2].Allocation.LayerInfo->bNoWeightBlend)
	{
		int32 BlendedLayerToMove = INDEX_NONE;

		// First try to swap layer 3 with an earlier blended layer
		// this will allow both to work
		for (int32 i = 1; i >= 0; --i)
		{
			if (MobileLayerAllocations[i].Allocation.LayerInfo && !MobileLayerAllocations[i].Allocation.LayerInfo->bNoWeightBlend)
			{
				BlendedLayerToMove = i;
				break;
			}
		}

		// otherwise swap layer 3 with the first weight-blended layer found
		// as non-blended layers aren't supported for layer 3 it wasn't going to work anyway, might as well swap it out for one that will work
		if (BlendedLayerToMove == INDEX_NONE)
		{
			// I wish I could specify a start index here, but it doesn't affect the result
			BlendedLayerToMove = MobileLayerAllocations.IndexOfByPredicate([](const FMobileLayerAllocation& MobileAllocation){ return MobileAllocation.Allocation.LayerInfo && !MobileAllocation.Allocation.LayerInfo->bNoWeightBlend; });
		}

		if (BlendedLayerToMove != INDEX_NONE)
		{
			// Preserve order of all but the blended layer we're moving into slot 3
			FMobileLayerAllocation TempAllocation = MoveTemp(MobileLayerAllocations[BlendedLayerToMove]);
			MobileLayerAllocations.RemoveAt(BlendedLayerToMove, 1, false);
			MobileLayerAllocations.Insert(MoveTemp(TempAllocation), 2);
		}
	}

	int32 WeightmapSize = (SubsectionSizeQuads + 1) * NumSubsections;
	UTexture2D* NewWeightNormalmapTexture = GetLandscapeProxy()->CreateLandscapeTexture(WeightmapSize, WeightmapSize, TEXTUREGROUP_Terrain_Weightmap, TSF_BGRA8);
	CreateEmptyTextureMips(NewWeightNormalmapTexture);

	{
		FLandscapeEditDataInterface LandscapeEdit(GetLandscapeInfo(false));

		if (WeightmapTextures.Num() > 0)
		{
			int32 CurrentIdx = 0;
			for (const auto& MobileAllocation : MobileLayerAllocations)
			{
				// Only for valid Layers
				if (MobileAllocation.Allocation.LayerInfo)
				{
					LandscapeEdit.CopyTextureFromWeightmap(NewWeightNormalmapTexture, CurrentIdx, this, MobileAllocation.Allocation.LayerInfo);
					CurrentIdx++;
					if (CurrentIdx >= 2) // Only support 2 layers in texture
					{
						break;
					}
				}
			}
		}

		// copy normals into B/A channels.
		LandscapeEdit.CopyTextureFromHeightmap(NewWeightNormalmapTexture, 2, this, 2);
		LandscapeEdit.CopyTextureFromHeightmap(NewWeightNormalmapTexture, 3, this, 3);
	}

	NewWeightNormalmapTexture->PostEditChange();

	MobileWeightNormalmapTexture = NewWeightNormalmapTexture;


	FLinearColor Masks[5];
	Masks[0] = FLinearColor(1, 0, 0, 0);
	Masks[1] = FLinearColor(0, 1, 0, 0);
	Masks[2] = FLinearColor(0, 0, 1, 0);
	Masks[3] = FLinearColor(0, 0, 0, 1);
	Masks[4] = FLinearColor(0, 0, 0, 0); // mask out layers 4+ altogether

	if (!bIsCooking)
	{
		UMaterialInstanceDynamic* NewMobileMaterialInstance = UMaterialInstanceDynamic::Create(MaterialInstance, GetOutermost());

		MobileBlendableLayerMask = 0;

		// Set the layer mask
		int32 CurrentIdx = 0;
		for (const auto& MobileAllocation : MobileLayerAllocations)
		{
			const FWeightmapLayerAllocationInfo& Allocation = MobileAllocation.Allocation;
			if (Allocation.LayerInfo)
			{
				FName LayerName = Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer ? UMaterialExpressionLandscapeVisibilityMask::ParameterName : Allocation.LayerInfo->LayerName;
				NewMobileMaterialInstance->SetVectorParameterValue(FName(*FString::Printf(TEXT("LayerMask_%s"), *LayerName.ToString())), Masks[FMath::Min(4, CurrentIdx)]);
				MobileBlendableLayerMask |= (!Allocation.LayerInfo->bNoWeightBlend ? (1 << CurrentIdx) : 0);
				CurrentIdx++;
			}
		}
		MobileMaterialInterface = NewMobileMaterialInstance;
	}
	else // for cooking
	{
		UMaterialInstanceConstant* CombinationMaterialInstance = GetCombinationMaterial(true);
		UMaterialInstanceConstant* NewMobileMaterialInstance = NewObject<ULandscapeMaterialInstanceConstant>(GetOutermost());

		NewMobileMaterialInstance->SetParentEditorOnly(CombinationMaterialInstance);

		MobileBlendableLayerMask = 0;

		// Set the layer mask
		int32 CurrentIdx = 0;
		for (const auto& MobileAllocation : MobileLayerAllocations)
		{
			const FWeightmapLayerAllocationInfo& Allocation = MobileAllocation.Allocation;
			if (Allocation.LayerInfo)
			{
				FName LayerName = Allocation.LayerInfo == ALandscapeProxy::VisibilityLayer ? UMaterialExpressionLandscapeVisibilityMask::ParameterName : Allocation.LayerInfo->LayerName;
				NewMobileMaterialInstance->SetVectorParameterValueEditorOnly(FName(*FString::Printf(TEXT("LayerMask_%s"), *LayerName.ToString())), Masks[FMath::Min(4, CurrentIdx)]);
				MobileBlendableLayerMask |= (!Allocation.LayerInfo->bNoWeightBlend ? (1 << CurrentIdx) : 0);
				CurrentIdx++;
			}
		}

		NewMobileMaterialInstance->PostEditChange();

		MobileMaterialInterface = NewMobileMaterialInstance;
	}
}

//
// Generates vertex buffer data from the component's heightmap texture, for use on platforms without vertex texture fetch
//
void ULandscapeComponent::GeneratePlatformVertexData()
{
	if (IsTemplate())
	{
		return;
	}
	check(HeightmapTexture);
	check(HeightmapTexture->Source.GetFormat() == TSF_BGRA8);

	TArray<uint8> NewPlatformData;
	int32 NewPlatformDataSize = 0;

	int32 SubsectionSizeVerts = SubsectionSizeQuads + 1;
	int32 MaxLOD = FMath::CeilLogTwo(SubsectionSizeVerts) - 1;

	float HeightmapSubsectionOffsetU = (float)(SubsectionSizeVerts) / (float)HeightmapTexture->Source.GetSizeX();
	float HeightmapSubsectionOffsetV = (float)(SubsectionSizeVerts) / (float)HeightmapTexture->Source.GetSizeY();

	NewPlatformDataSize += sizeof(FLandscapeMobileVertex) * FMath::Square(SubsectionSizeVerts * NumSubsections);
	NewPlatformData.AddZeroed(NewPlatformDataSize);

	// Get the required mip data
	TArray<FColor*> HeightmapMipData;
	for (int32 MipIdx = 0; MipIdx < FMath::Min(LANDSCAPE_MAX_ES_LOD, HeightmapTexture->Source.GetNumMips()); MipIdx++)
	{
		int32 MipSubsectionSizeVerts = (SubsectionSizeVerts) >> MipIdx;
		if (MipSubsectionSizeVerts > 1)
		{
			HeightmapMipData.Add((FColor*)HeightmapTexture->Source.LockMip(MipIdx));
		}
	}

	TMap<uint64, int32> VertexMap;
	TArray<FLandscapeVertexRef> VertexOrder;
	VertexOrder.Empty(FMath::Square(SubsectionSizeVerts * NumSubsections));

	// Layout index buffer to determine best vertex order
	for (int32 Mip = MaxLOD; Mip >= 0; Mip--)
	{
		int32 LodSubsectionSizeQuads = (SubsectionSizeVerts >> Mip) - 1;
		float MipRatio = (float)SubsectionSizeQuads / (float)LodSubsectionSizeQuads; // Morph current MIP to base MIP

		for (int32 SubY = 0; SubY < NumSubsections; SubY++)
		{
			for (int32 SubX = 0; SubX < NumSubsections; SubX++)
			{
				for (int32 y = 0; y < LodSubsectionSizeQuads; y++)
				{
					for (int32 x = 0; x < LodSubsectionSizeQuads; x++)
					{
						int32 x0 = FMath::RoundToInt((float)x * MipRatio);
						int32 y0 = FMath::RoundToInt((float)y * MipRatio);
						int32 x1 = FMath::RoundToInt((float)(x + 1) * MipRatio);
						int32 y1 = FMath::RoundToInt((float)(y + 1) * MipRatio);

						FLandscapeVertexRef V1(x0, y0, SubX, SubY);
						FLandscapeVertexRef V2(x1, y0, SubX, SubY);
						FLandscapeVertexRef V3(x1, y1, SubX, SubY);
						FLandscapeVertexRef V4(x0, y1, SubX, SubY);

						uint64 Key1 = V1.MakeKey();
						if (VertexMap.Find(Key1) == NULL)
						{
							VertexMap.Add(Key1, VertexOrder.Num());
							VertexOrder.Add(V1);
						}
						uint64 Key2 = V2.MakeKey();
						if (VertexMap.Find(Key2) == NULL)
						{
							VertexMap.Add(Key2, VertexOrder.Num());
							VertexOrder.Add(V2);
						}
						uint64 Key3 = V3.MakeKey();
						if (VertexMap.Find(Key3) == NULL)
						{
							VertexMap.Add(Key3, VertexOrder.Num());
							VertexOrder.Add(V3);
						}
						uint64 Key4 = V4.MakeKey();
						if (VertexMap.Find(Key4) == NULL)
						{
							VertexMap.Add(Key4, VertexOrder.Num());
							VertexOrder.Add(V4);
						}
					}
				}
			}
		}
	}
	check(VertexOrder.Num() == FMath::Square(SubsectionSizeVerts) * FMath::Square(NumSubsections));

	// Fill in the vertices in the specified order
	FLandscapeMobileVertex* DstVert = (FLandscapeMobileVertex*)NewPlatformData.GetData();
	for (int32 Idx = 0; Idx < VertexOrder.Num(); Idx++)
	{
		int32 X = VertexOrder[Idx].X;
		int32 Y = VertexOrder[Idx].Y;
		int32 SubX = VertexOrder[Idx].SubX;
		int32 SubY = VertexOrder[Idx].SubY;

		float HeightmapScaleBiasZ = HeightmapScaleBias.Z + HeightmapSubsectionOffsetU * (float)SubX;
		float HeightmapScaleBiasW = HeightmapScaleBias.W + HeightmapSubsectionOffsetV * (float)SubY;
		int32 BaseMipOfsX = FMath::RoundToInt(HeightmapScaleBiasZ * (float)HeightmapTexture->Source.GetSizeX());
		int32 BaseMipOfsY = FMath::RoundToInt(HeightmapScaleBiasW * (float)HeightmapTexture->Source.GetSizeY());

		DstVert->Position[0] = X;
		DstVert->Position[1] = Y;
		DstVert->Position[2] = SubX;
		DstVert->Position[3] = SubY;

		TArray<int32> MipHeights;
		MipHeights.AddZeroed(HeightmapMipData.Num());
		int32 LastIndex = 0;
		uint16 MaxHeight = 0, MinHeight = 65535;

		for (int32 Mip = 0; Mip < HeightmapMipData.Num(); ++Mip)
		{
			int32 MipSizeX = HeightmapTexture->Source.GetSizeX() >> Mip;

			int32 CurrentMipOfsX = BaseMipOfsX >> Mip;
			int32 CurrentMipOfsY = BaseMipOfsY >> Mip;

			int32 MipX = X >> Mip;
			int32 MipY = Y >> Mip;

			FColor* CurrentMipSrcRow = HeightmapMipData[Mip] + (CurrentMipOfsY + MipY) * MipSizeX + CurrentMipOfsX;
			uint16 Height = CurrentMipSrcRow[MipX].R << 8 | CurrentMipSrcRow[MipX].G;

			MipHeights[Mip] = Height;
			MaxHeight = FMath::Max(MaxHeight, Height);
			MinHeight = FMath::Min(MinHeight, Height);
		}

		DstVert->LODHeights[0] = MinHeight >> 8;
		DstVert->LODHeights[1] = (MinHeight & 255);
		DstVert->LODHeights[2] = MaxHeight >> 8;
		DstVert->LODHeights[3] = (MaxHeight & 255);

		for (int32 Mip = 0; Mip < HeightmapMipData.Num(); ++Mip)
		{
			if (Mip < 4)
			{
				DstVert->LODHeights[4 + Mip] = FMath::RoundToInt(float(MipHeights[Mip] - MinHeight) / (MaxHeight - MinHeight) * 255);
			}
			else // Mip 4 5 packed into SubX, SubY
			{
				DstVert->Position[Mip - 2] += (FMath::RoundToInt(float(MipHeights[Mip] - MinHeight) / (MaxHeight - MinHeight) * 255)) & (0xfffe);
			}
		}

		DstVert++;
	}

	for (int32 MipIdx = 0; MipIdx < HeightmapTexture->Source.GetNumMips(); MipIdx++)
	{
		HeightmapTexture->Source.UnlockMip(MipIdx);
	}

	// Copy to PlatformData as Compressed
	PlatformData.InitializeFromUncompressedData(NewPlatformData);
}

UTexture2D* ALandscapeProxy::CreateLandscapeTexture(int32 InSizeX, int32 InSizeY, TextureGroup InLODGroup, ETextureSourceFormat InFormat, UObject* OptionalOverrideOuter) const
{
	UObject* TexOuter = OptionalOverrideOuter ? OptionalOverrideOuter : GetOutermost();
	UTexture2D* NewTexture = NewObject<UTexture2D>(TexOuter);
	NewTexture->Source.Init2DWithMipChain(InSizeX, InSizeY, InFormat);
	NewTexture->SRGB = false;
	NewTexture->CompressionNone = true;
	NewTexture->MipGenSettings = TMGS_LeaveExistingMips;
	NewTexture->AddressX = TA_Clamp;
	NewTexture->AddressY = TA_Clamp;
	NewTexture->LODGroup = InLODGroup;

	return NewTexture;
}

void ALandscapeProxy::RemoveOverlappingComponent(ULandscapeComponent* Component)
{
	Modify();
	Component->Modify();
	if (Component->CollisionComponent.IsValid() && (Component->CollisionComponent->RenderComponent.Get() == Component || Component->CollisionComponent->RenderComponent.IsNull()))
	{
		Component->CollisionComponent->Modify();
		CollisionComponents.Remove(Component->CollisionComponent.Get());
		Component->CollisionComponent.Get()->DestroyComponent();
	}
	LandscapeComponents.Remove(Component);
	Component->DestroyComponent();
}

#endif //WITH_EDITOR

#undef LOCTEXT_NAMESPACE