UnrealEngineUWP/Engine/Source/Developer/SimplygonMeshReduction/Private/SimplygonMeshReduction.cpp

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

#include "UnrealEd.h"
#include "RawMesh.h"
#include "MeshUtilities.h"

// Standard Simplygon channels have some issues with extracting color data back from simplification, 
// so we use this workaround with user channels
static const char* USER_MATERIAL_CHANNEL_METALLIC = "UserMetallic";
static const char* USER_MATERIAL_CHANNEL_ROUGHNESS = "UserRoughness";
static const char* USER_MATERIAL_CHANNEL_SPECULAR = "UserSpecular";


#ifdef __clang__
	// SimplygonSDK.h uses 'deprecated' pragma which Clang does not recognize
	#pragma clang diagnostic push
	#pragma clang diagnostic ignored "-Wunknown-pragmas"	// warning : unknown pragma ignored [-Wunknown-pragmas]
#endif

#include "SimplygonSDK.h"

#ifdef __clang__
	#pragma clang diagnostic pop
#endif

#include "MeshBoneReduction.h"
#include "MaterialExportUtils.h"
#include "ComponentReregisterContext.h"

#define LOCTEXT_NAMESPACE "SimplygonMeshReduction"

class FSimplygonMeshReductionModule : public IMeshReductionModule
{
public:
	// IModuleInterface interface.
	virtual void StartupModule() override;
	virtual void ShutdownModule() override;

	// IMeshReductionModule interface.
	virtual class IMeshReduction* GetMeshReductionInterface() override;
	virtual class IMeshMerging* GetMeshMergingInterface() override;
};


DEFINE_LOG_CATEGORY_STATIC(LogSimplygon, Log, All);
IMPLEMENT_MODULE(FSimplygonMeshReductionModule, SimplygonMeshReduction);

#define SIMPLYGON_COLOR_CHANNEL "VertexColors"

/** Receives error messages generated by Simplygon. These errors are presented via a message box. */
class FDefaultErrorHandler : public SimplygonSDK::rerrorhandler
{
public :
	virtual void HandleError(
		SimplygonSDK::IObject* Object,
		const char* InterfaceName,
		const char* MethodName,
		SimplygonSDK::rid ErrorType,
		const char* ErrorText )
	{
		FString ErrorString = FString::Printf(TEXT("Simplygon Error:\n\nInterface: %s\nMethod: %s\nError: (%d) %s"),
			ANSI_TO_TCHAR(InterfaceName),
			ANSI_TO_TCHAR(MethodName),
			ErrorType,
			ANSI_TO_TCHAR(ErrorText)
			);
		UE_LOG(LogSimplygon, Log, TEXT("%s"), *ErrorString);
		//FMessageDialog::Open(EAppMsgType::Ok, *ErrorString);
	}
};

/** Receives progress events from Simplygon and updates the status window. */
class FDefaultEventHandler : public SimplygonSDK::robserver
{
public:
	virtual void Execute(
		SimplygonSDK::IObject* Object,
		SimplygonSDK::rid EventId,
		void* EventParameterBlock,
		unsigned int EventParameterBlockSize )
	{
		if ( EventId == SimplygonSDK::SG_EVENT_PROGRESS )
		{
			check( sizeof(int32) == EventParameterBlockSize );
			int32 ProgressPercent = *((int32*)EventParameterBlock);
			GWarn->UpdateProgress( ProgressPercent, 100 );

			// We are required to pass '1' back through the EventParametersBlock for the process to continue.
			*((int32*)EventParameterBlock) = 1;
		}
	}
};

/** Winding modes. */
enum EWindingMode
{
	/** Maintain the winding of the mesh. */
	WINDING_Keep,
	/** Reverse the winding of the mesh. */
	WINDING_Reverse,
	WINDING_MAX
};

class FSimplygonMeshReduction 
	: public IMeshReduction 
	, public IMeshMerging
{
public:
	virtual ~FSimplygonMeshReduction()
	{
	}

	virtual const FString& GetVersionString() const override
	{
		return VersionString;
	}

	virtual void Reduce(
		FRawMesh& OutReducedMesh,
		float& OutMaxDeviation,
		const FRawMesh& InMesh,
		const FMeshReductionSettings& InSettings
		) override
	{
		SimplygonSDK::spGeometryData GeometryData = CreateGeometryFromRawMesh(InMesh);
		check(GeometryData);

		SimplygonSDK::spReductionProcessor ReductionProcessor = SDK->CreateReductionProcessor();
		ReductionProcessor->AddObserver(&EventHandler, SimplygonSDK::SG_EVENT_PROGRESS);
		ReductionProcessor->SetGeometry(GeometryData);

		SimplygonSDK::spRepairSettings RepairSettings = ReductionProcessor->GetRepairSettings();
		RepairSettings->SetWeldDist(InSettings.WeldingThreshold);
		RepairSettings->SetTjuncDist(InSettings.WeldingThreshold);

		SimplygonSDK::spReductionSettings ReductionSettings = ReductionProcessor->GetReductionSettings();
		SetReductionSettings(ReductionSettings, InSettings, GeometryData->GetTriangleCount());

		SimplygonSDK::spNormalCalculationSettings NormalSettings = ReductionProcessor->GetNormalCalculationSettings();
		SetNormalSettings(NormalSettings, InSettings);			

		ReductionProcessor->RunProcessing();

		CreateRawMeshFromGeometry(OutReducedMesh, GeometryData, WINDING_Keep);
		OutMaxDeviation = ReductionProcessor->GetMaxDeviation();
	}

	bool ReduceLODModel(
		FStaticLODModel * SrcModel,
		FStaticLODModel *& OutModel, 
		FBoxSphereBounds & Bounds, 
		float &MaxDeviation, 
		const FReferenceSkeleton& RefSkeleton, 
		const FSkeletalMeshOptimizationSettings& Settings
		)
	{
		const bool bUsingMaxDeviation = (Settings.ReductionMethod == SMOT_MaxDeviation && Settings.MaxDeviationPercentage > 0.0f);
		const bool bUsingReductionRatio = (Settings.ReductionMethod == SMOT_NumOfTriangles && Settings.NumOfTrianglesPercentage < 1.0f);
		const bool bProcessGeometry = ( bUsingMaxDeviation || bUsingReductionRatio );
		const bool bProcessBones = (Settings.BoneReductionRatio < 1.0f || Settings.MaxBonesPerVertex < MAX_TOTAL_INFLUENCES);
		const bool bOptimizeMesh = (bProcessGeometry || bProcessBones);

		// We'll need to store the max deviation after optimization if we wish to recalculate the LOD's display distance
		MaxDeviation = 0.0f;

		if ( bOptimizeMesh )
		{
			//Create a simplygon scene. The scene by default contains a bone table that is required for bone reduction.
			SimplygonSDK::spScene Scene = SDK->CreateScene();
			check( Scene );

			// Create bone hierarchy for simplygon.
			TArray<SimplygonSDK::rid> BoneTableIDs; 
			CreateSkeletalHierarchy(Scene, RefSkeleton, BoneTableIDs);

			// Create a new scene mesh object
			SimplygonSDK::spGeometryData GeometryData = CreateGeometryFromSkeletalLODModel( Scene, *SrcModel, BoneTableIDs );

			FDefaultEventHandler SimplygonEventHandler;
			SimplygonSDK::spReductionProcessor ReductionProcessor = SDK->CreateReductionProcessor();
			ReductionProcessor->AddObserver( &EventHandler, SimplygonSDK::SG_EVENT_PROGRESS );
			ReductionProcessor->SetSceneRoot(Scene->GetRootNode());

			SimplygonSDK::spRepairSettings RepairSettings = ReductionProcessor->GetRepairSettings();
			RepairSettings->SetWeldDist( Settings.WeldingThreshold );
			RepairSettings->SetTjuncDist( Settings.WeldingThreshold );

			SimplygonSDK::spReductionSettings ReductionSettings = ReductionProcessor->GetReductionSettings();
			SetReductionSettings( Settings, Bounds.SphereRadius, GeometryData->GetTriangleCount(), ReductionSettings );

			SimplygonSDK::spNormalCalculationSettings NormalSettings = ReductionProcessor->GetNormalCalculationSettings();
			SetNormalSettings( Settings, NormalSettings );

			if(bProcessBones)
			{
				SimplygonSDK::spBoneSettings BoneSettings = ReductionProcessor->GetBoneSettings();
				SetBoneSettings( Settings, BoneSettings );
			}

			ReductionProcessor->RunProcessing();

			// We require the max deviation if we're calculating the LOD's display distance.
			MaxDeviation = ReductionProcessor->GetMaxDeviation();

			CreateSkeletalLODModelFromGeometry( GeometryData, RefSkeleton, OutModel );
		}

		return bOptimizeMesh;
	}
	virtual bool ReduceSkeletalMesh(
		USkeletalMesh* SkeletalMesh,
		int32 LODIndex,
		const FSkeletalMeshOptimizationSettings& Settings,
		bool bCalcLODDistance
		) override
	{
		check( SkeletalMesh );
		check( LODIndex >= 0 );
		check( LODIndex <= SkeletalMesh->LODInfo.Num() );

		FSkeletalMeshResource* SkeletalMeshResource = SkeletalMesh->GetImportedResource();
		check(SkeletalMeshResource);
		check( LODIndex <= SkeletalMeshResource->LODModels.Num() );

		FStaticLODModel* SrcModel = &SkeletalMesh->PreModifyMesh();

		TComponentReregisterContext<USkinnedMeshComponent> ReregisterContext;
		SkeletalMesh->ReleaseResources();
		SkeletalMesh->ReleaseResourcesFence.Wait();

		// Insert a new LOD model entry if needed.
		if ( LODIndex == SkeletalMeshResource->LODModels.Num() )
		{
			SkeletalMeshResource->LODModels.Add(0);
		}

		// We'll need to store the max deviation after optimization if we wish to recalculate the LOD's display distance
		float MaxDeviation = 0.0f;

		// Swap in a new model, delete the old.
		check( LODIndex < SkeletalMeshResource->LODModels.Num() );
		FStaticLODModel** LODModels = SkeletalMeshResource->LODModels.GetData();
		delete LODModels[LODIndex];

		// Copy over LOD info from LOD0 if there is no previous info.
		if ( LODIndex == SkeletalMesh->LODInfo.Num() )
		{
			FSkeletalMeshLODInfo* NewLODInfo = new( SkeletalMesh->LODInfo ) FSkeletalMeshLODInfo;
			FSkeletalMeshLODInfo& OldLODInfo = SkeletalMesh->LODInfo[0];
			*NewLODInfo = OldLODInfo;

			// creates LOD Material map for a newly generated LOD model
			int32 NumSections = LODModels[0]->NumNonClothingSections();
			if (NewLODInfo->LODMaterialMap.Num() != NumSections)
			{
				NewLODInfo->LODMaterialMap.Empty(NumSections);
				NewLODInfo->LODMaterialMap.AddUninitialized(NumSections);
			}

			for (int32 Index = 0; Index < NumSections; Index++)
			{
				NewLODInfo->LODMaterialMap[Index] = Index;
			}
		}

		// now try bone reduction process if it's setup
		TMap<FBoneIndexType, FBoneIndexType> BonesToRemove;

        IMeshBoneReductionModule& MeshBoneReductionModule = FModuleManager::Get().LoadModuleChecked<IMeshBoneReductionModule>("MeshBoneReduction");
		IMeshBoneReduction * MeshBoneReductionInterface = MeshBoneReductionModule.GetMeshBoneReductionInterface();

		// See if we'd like to remove extra bones first
		if (MeshBoneReductionInterface->GetBoneReductionData( SkeletalMesh, LODIndex, BonesToRemove ))
		{
			// if we do, now create new model and make a copy of SrcMesh to cut the bone count
			FStaticLODModel * NewSrcModel = new FStaticLODModel();
			
			//	Bulk data arrays need to be locked before a copy can be made.
			SrcModel->RawPointIndices.Lock( LOCK_READ_ONLY );
			SrcModel->LegacyRawPointIndices.Lock( LOCK_READ_ONLY );
			*NewSrcModel = *SrcModel;
			SrcModel->RawPointIndices.Unlock();
			SrcModel->LegacyRawPointIndices.Unlock();

			// The index buffer needs to be rebuilt on copy.
			FMultiSizeIndexContainerData IndexBufferData;
			SrcModel->MultiSizeIndexContainer.GetIndexBufferData( IndexBufferData );
			NewSrcModel->MultiSizeIndexContainer.RebuildIndexBuffer( IndexBufferData );

			// now fix up SrcModel to NewSrcModel
			SrcModel = NewSrcModel;

			// fix up chunks to remove the bones that set to be removed
			for ( int32 ChunkIndex=0; ChunkIndex< NewSrcModel->Chunks.Num(); ++ChunkIndex )	
			{
				MeshBoneReductionInterface->FixUpChunkBoneMaps(NewSrcModel->Chunks[ChunkIndex], BonesToRemove);
			}
		}

		FStaticLODModel * NewModel = new FStaticLODModel();
		LODModels[LODIndex] = NewModel;

		// Reduce LOD model with SrcMesh
		if ( ReduceLODModel(SrcModel, NewModel, SkeletalMesh->Bounds, MaxDeviation, SkeletalMesh->RefSkeleton, Settings) )
		{
			if( bCalcLODDistance )
			{
				float ViewDistance = CalculateViewDistance( MaxDeviation );
				SkeletalMesh->LODInfo[LODIndex].ScreenSize = 2.0f * SkeletalMesh->Bounds.SphereRadius / ViewDistance;
			}

			// Flag this LOD as having been simplified.
			SkeletalMesh->LODInfo[LODIndex].bHasBeenSimplified = true;
			SkeletalMesh->bHasBeenSimplified = true;
		}
		else
		{
			//	Bulk data arrays need to be locked before a copy can be made.
			SrcModel->RawPointIndices.Lock( LOCK_READ_ONLY );
			SrcModel->LegacyRawPointIndices.Lock( LOCK_READ_ONLY );
			*NewModel = *SrcModel;
			SrcModel->RawPointIndices.Unlock();
			SrcModel->LegacyRawPointIndices.Unlock();

			// The index buffer needs to be rebuilt on copy.
			FMultiSizeIndexContainerData IndexBufferData;
			SrcModel->MultiSizeIndexContainer.GetIndexBufferData( IndexBufferData );
			NewModel->MultiSizeIndexContainer.RebuildIndexBuffer( IndexBufferData );

			// Required bones are recalculated later on.
			NewModel->RequiredBones.Empty();
			SkeletalMesh->LODInfo[LODIndex].bHasBeenSimplified = false;
		}

		SkeletalMesh->CalculateRequiredBones( SkeletalMeshResource->LODModels[LODIndex], SkeletalMesh->RefSkeleton, &BonesToRemove );
		SkeletalMesh->PostEditChange();
		SkeletalMesh->InitResources();
		
		if ( LODIndex >= SkeletalMesh->OptimizationSettings.Num() )
		{
			FSkeletalMeshOptimizationSettings DefaultSettings;
			const FSkeletalMeshOptimizationSettings SettingsToCopy =
				SkeletalMesh->OptimizationSettings.Num() ? SkeletalMesh->OptimizationSettings.Last() : DefaultSettings;
			while ( LODIndex >= SkeletalMesh->OptimizationSettings.Num() )
			{
				SkeletalMesh->OptimizationSettings.Add( SettingsToCopy );
			}
		}
		check( LODIndex < SkeletalMesh->OptimizationSettings.Num() );
		SkeletalMesh->OptimizationSettings[ LODIndex ] = Settings;

		return true;
	}
	
	virtual bool IsSupported() const override
	{
		return true;
	}
	static FSimplygonMeshReduction* Create()
	{
		FString DllPath(FPaths::Combine(*FPaths::EngineDir(), TEXT("Binaries/ThirdParty/NotForLicensees/Simplygon")));
		FString DllFilename(FPaths::Combine(*DllPath, TEXT("SimplygonSDKEpicUE4Releasex64.dll")));
		if( !FPaths::FileExists(DllFilename) )
		{
			DllFilename = FPaths::Combine(*DllPath, TEXT("SimplygonSDKRuntimeReleasex64.dll"));
		}

		// If the DLL just doesn't exist, fail gracefully. Licensees and Rocket users will not necessarily have Simplygon.
		if( !FPaths::FileExists(DllFilename) )
		{
			UE_LOG(LogSimplygon,Warning,TEXT("Simplygon DLL not present - disabling."));
			return NULL;
		}

		// Otherwise fail
		void* DLLHandle = FPlatformProcess::GetDllHandle(*DllFilename);
		if (DLLHandle == NULL)
		{
			int32 ErrorNum = FPlatformMisc::GetLastError();
			TCHAR ErrorMsg[1024];
			FPlatformMisc::GetSystemErrorMessage( ErrorMsg, 1024, ErrorNum );
			UE_LOG(LogSimplygon,Error,TEXT("Failed to get Simplygon DLL handle: %s (%d)"),ErrorMsg,ErrorNum);
			return NULL;
		}

		// Get API function pointers of interest
		typedef void (*GetInterfaceVersionSimplygonSDKPtr)(ANSICHAR*);
		GetInterfaceVersionSimplygonSDKPtr GetInterfaceVersionSimplygonSDK = (GetInterfaceVersionSimplygonSDKPtr)FPlatformProcess::GetDllExport( DLLHandle, TEXT( "GetInterfaceVersionSimplygonSDK" ) );

		typedef int (*InitializeSimplygonSDKPtr)(const char* LicenseData , SimplygonSDK::ISimplygonSDK** OutInterfacePtr);
		InitializeSimplygonSDKPtr InitializeSimplygonSDK = (InitializeSimplygonSDKPtr)FPlatformProcess::GetDllExport( DLLHandle, TEXT( "InitializeSimplygonSDK" ) );
 
		if ((GetInterfaceVersionSimplygonSDK == NULL) || (InitializeSimplygonSDK == NULL))
		{
			// Couldn't find the functions we need.  
			UE_LOG(LogSimplygon,Warning,TEXT("Failed to acquire Simplygon DLL exports."));
			FPlatformProcess::FreeDllHandle( DLLHandle );
			return NULL;
		}

		ANSICHAR VersionHash[200];
		GetInterfaceVersionSimplygonSDK(VersionHash);
		if (FCStringAnsi::Strcmp(VersionHash, SimplygonSDK::GetInterfaceVersionHash()) != 0)
		{
			UE_LOG(LogSimplygon,Warning,TEXT("Library version mismatch. Header=%s Lib=%s"),ANSI_TO_TCHAR(SimplygonSDK::GetInterfaceVersionHash()),ANSI_TO_TCHAR(VersionHash));
			return NULL;
		}

		const char* LicenseData = NULL;
		TArray<uint8> LicenseFileContents;
		if (FFileHelper::LoadFileToArray(LicenseFileContents, *FPaths::Combine(*DllPath, TEXT("license.dat")), FILEREAD_Silent) && LicenseFileContents.Num() > 0)
		{
			LicenseData = (const char*)LicenseFileContents.GetData();
		}

		SimplygonSDK::ISimplygonSDK* SDK = NULL;
		int32 Result = InitializeSimplygonSDK(LicenseData, &SDK);
		if (Result != SimplygonSDK::SG_ERROR_NOERROR && Result != SimplygonSDK::SG_ERROR_ALREADYINITIALIZED)
		{
			UE_LOG(LogSimplygon,Warning,TEXT("Failed to initialize Simplygon. Error: %d."),Result);
			SDK = NULL;
			return NULL;
		}

		return new FSimplygonMeshReduction(SDK);
	}

	struct FMaterialCastingProperties
	{
		bool bCastMaterials;
		bool bCastNormals;
		bool bCastMetallic;
		bool bCastRoughness;
		bool bCastSpecular;

		FMaterialCastingProperties()
			: bCastMaterials(false)
			, bCastNormals(false)
			, bCastMetallic(false)
			, bCastRoughness(false)
			, bCastSpecular(false)
		{
		}
	};

	// IMeshMerging interface
	virtual void BuildProxy(
		const TArray<FRawMesh>& InputMeshes,
		const TArray<MaterialExportUtils::FFlattenMaterial>& InputMaterials,
		const struct FMeshProxySettings& InProxySettings,
		FRawMesh& OutProxyMesh,
		MaterialExportUtils::FFlattenMaterial& OutMaterial) override
	{
		if (InputMeshes.Num() == 0)
		{
			return;
		}

		//Create a Simplygon Scene
		SimplygonSDK::spScene Scene = SDK->CreateScene();
		//Material table for the original materials
		SimplygonSDK::spMaterialTable OriginalMaterials = Scene->GetMaterialTable();
	
		//Build simplygon materials from the original asset materials
		FMaterialCastingProperties CastProperties;
		CastProperties.bCastMaterials = CreateSGMaterialFromFlattenMaterial(InputMaterials, OriginalMaterials, CastProperties);

		//For each raw mesh in array create a scene mesh and populate with geometry data
		for(int32 MeshIndex = 0; MeshIndex < InputMeshes.Num() ; ++MeshIndex)
		{
			SimplygonSDK::spSceneMesh Mesh = SDK->CreateSceneMesh();
			SimplygonSDK::spGeometryData GeometryData = CreateGeometryFromRawMesh(InputMeshes[MeshIndex]);
			check(GeometryData)

#ifdef DEBUG_PROXY_MESH
			SimplygonSDK::spWavefrontExporter objexp = SDK->CreateWavefrontExporter();
			objexp->SetExportFilePath( "d:/BeforeProxyMesh.obj" );
			objexp->SetSingleGeometry( GeometryData);
			objexp->RunExport();
#endif
			Mesh->SetGeometry(GeometryData);
			Mesh->SetName(TCHAR_TO_ANSI(*FString::Printf(TEXT("Mesh%d"),MeshIndex)));
			Scene->GetRootNode()->AddChild(Mesh);
		}
		

		//Create a remesher
		SimplygonSDK::spRemeshingProcessor RemeshingProcessor = SDK->CreateRemeshingProcessor();

		//Setup the remesher
		RemeshingProcessor->AddObserver(&EventHandler, SimplygonSDK::SG_EVENT_PROGRESS);
		RemeshingProcessor->GetRemeshingSettings()->SetOnScreenSize(InProxySettings.ScreenSize);
		RemeshingProcessor->GetRemeshingSettings()->SetMergeDistance(InProxySettings.MergeDistance);
		RemeshingProcessor->GetRemeshingSettings()->SetUseGroundPlane(InProxySettings.bUseClippingPlane);
		RemeshingProcessor->GetRemeshingSettings()->SetGroundPlaneAxisIndex(InProxySettings.AxisIndex); // 0:X-Axis, 1:Y-Axis, 2:Z-Axis
		RemeshingProcessor->GetRemeshingSettings()->SetGroundPlaneLevel(InProxySettings.ClippingLevel);
		
		// Goal is: If user specifies negative clipping plane -> negative halfspace should be clipped
		if (InProxySettings.AxisIndex <= 1) // Invert X and Y axis
		{
			RemeshingProcessor->GetRemeshingSettings()->SetGroundPlaneNegativeHalfspace(!InProxySettings.bPlaneNegativeHalfspace);
		}
		else
		{
			RemeshingProcessor->GetRemeshingSettings()->SetGroundPlaneNegativeHalfspace(InProxySettings.bPlaneNegativeHalfspace);
		}
		
		RemeshingProcessor->GetRemeshingSettings()->SetTransferNormals( false );
		RemeshingProcessor->GetRemeshingSettings()->SetMergeDistance( InProxySettings.MergeDistance );
		RemeshingProcessor->GetRemeshingSettings()->SetHardEdgeAngle( FMath::DegreesToRadians(InProxySettings.HardAngleThreshold) );//This should be a user settings in the popup dialog!
		RemeshingProcessor->SetSceneRoot(Scene->GetRootNode());

		//Setup the mapping image used for casting
		SimplygonSDK::spMappingImageSettings MappingSettings = RemeshingProcessor->GetMappingImageSettings();
		MappingSettings->SetGenerateMappingImage( true );
		MappingSettings->SetGenerateTexCoords( true );
		MappingSettings->SetGenerateTangents( false );
		MappingSettings->SetWidth( InProxySettings.TextureWidth );
		MappingSettings->SetHeight( InProxySettings.TextureHeight );

		//Start remeshing the geometry
		RemeshingProcessor->RemeshGeometry();
	 
		if(CastProperties.bCastMaterials)
		{
			//Collect the mapping image from the remeshing process
			SimplygonSDK::spMappingImage MappingImage = RemeshingProcessor->GetMappingImage();

			//Create a new material for the proxy geometry
			SimplygonSDK::spMaterial OutputMaterialLOD = SDK->CreateMaterial();

			//Cast diffuse texture data
			{
				//Create Image data where the diffuse data is stored
				SimplygonSDK::spImageData OutputDiffuseData = SDK->CreateImageData();
				// Cast the data using a color caster
				SimplygonSDK::spColorCaster cast = SDK->CreateColorCaster();
				cast->SetColorType( SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE );
				cast->SetSourceMaterials( OriginalMaterials );
				cast->SetMappingImage( MappingImage ); // The mapping image we got from the remeshing process.
				cast->SetOutputChannels( 4 ); // RGB, 3 channels! (1 would be for grey scale, and 4 would be for RGBA.)
				cast->SetOutputChannelBitDepth( 8 ); // 8 bits per channel. So in this case we will have 24bit colors RGB.
				cast->SetDilation( 10 ); // To avoid mip-map artifacts, the empty pixels on the map needs to be filled to a degree aswell.
				cast->SetOutputImage(OutputDiffuseData);
				cast->CastMaterials(); // Fetch!

				// set the material properties 
				// Set the diffuse multiplier for the texture. 1 means it will not differ from original texture,
				// For example: 0 would ignore a specified color and 2 would make a color twice as pronounced as the others.
				OutputMaterialLOD->SetDiffuseRed(1);
				OutputMaterialLOD->SetDiffuseGreen(1);
				OutputMaterialLOD->SetDiffuseBlue(1);
				OutputMaterialLOD->SetLayeredTextureImage(SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE, 0, OutputDiffuseData);
				OutputMaterialLOD->SetLayeredTextureLevel(SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE,0,0);
			}

			
			// Normal texture data
			if(CastProperties.bCastNormals)
			{
				//Create Image data where the normal data is stored
				SimplygonSDK::spImageData OutputNormalData = SDK->CreateImageData();

				// Cast the data using a normal caster
				SimplygonSDK::spNormalCaster cast = SDK->CreateNormalCaster();
				cast->SetSourceMaterials( OriginalMaterials );
				cast->SetMappingImage( MappingImage ); // The mapping image we got from the remeshing process.
				cast->SetOutputChannels( 3 ); // RGB, 3 channels! (1 would be for grey scale, and 4 would be for RGBA.)
				cast->SetOutputChannelBitDepth( 8 ); // 8 bits per channel. So in this case we will have 24bit colors RGB.
				cast->SetDilation( 10 ); // To avoid mip-map artifacts, the empty pixels on the map needs to be filled to a degree aswell.
				cast->SetFlipBackfacingNormals(false);
				cast->SetGenerateTangentSpaceNormals(true);
				cast->SetOutputImage(OutputNormalData);
				cast->CastMaterials(); // Fetch!

				OutputMaterialLOD->SetLayeredTextureImage(SimplygonSDK::SG_MATERIAL_CHANNEL_NORMALS, 0, OutputNormalData);
				OutputMaterialLOD->SetLayeredTextureLevel(SimplygonSDK::SG_MATERIAL_CHANNEL_NORMALS, 0, 0);
			}

			// Metallic texture data
			if(CastProperties.bCastMetallic)
			{
				// Create Image data where the metallic data is stored
				SimplygonSDK::spImageData OutputMetallicData = SDK->CreateImageData();
				// Cast the data using a color caster
				SimplygonSDK::spColorCaster cast = SDK->CreateColorCaster();
				cast->SetColorType( USER_MATERIAL_CHANNEL_METALLIC );
				cast->SetSourceMaterials( OriginalMaterials );
				cast->SetMappingImage( MappingImage );
				cast->SetOutputChannels( 3 );
				cast->SetOutputChannelBitDepth( 8 );
				cast->SetsRGB(false);
				cast->SetDilation( 10 );
				cast->SetOutputImage(OutputMetallicData);
				cast->CastMaterials(); // Fetch!

				OutputMaterialLOD->AddUserChannel(USER_MATERIAL_CHANNEL_METALLIC);
				OutputMaterialLOD->SetLayeredTextureImage(USER_MATERIAL_CHANNEL_METALLIC, 0, OutputMetallicData);
				OutputMaterialLOD->SetLayeredTextureLevel(USER_MATERIAL_CHANNEL_METALLIC, 0, 0);
			}

			// Roughness texture data
			if(CastProperties.bCastRoughness)
			{
				// Create Image data where the metallic data is stored
				SimplygonSDK::spImageData OutputRoughnessData = SDK->CreateImageData();
				// Cast the data using a color caster
				SimplygonSDK::spColorCaster cast = SDK->CreateColorCaster();
				cast->SetColorType( USER_MATERIAL_CHANNEL_ROUGHNESS );
				cast->SetSourceMaterials( OriginalMaterials );
				cast->SetMappingImage( MappingImage ); 
				cast->SetOutputChannels( 3 );
				cast->SetOutputChannelBitDepth( 8 );
				cast->SetsRGB(false);
				cast->SetDilation( 10 ); 
				cast->SetOutputImage(OutputRoughnessData);
				cast->CastMaterials(); // Fetch!

				OutputMaterialLOD->AddUserChannel(USER_MATERIAL_CHANNEL_ROUGHNESS);
				OutputMaterialLOD->SetLayeredTextureImage(USER_MATERIAL_CHANNEL_ROUGHNESS, 0, OutputRoughnessData);
				OutputMaterialLOD->SetLayeredTextureLevel(USER_MATERIAL_CHANNEL_ROUGHNESS, 0, 0);
			}

			// Specular texture data
			if(CastProperties.bCastSpecular)
			{
				// Create Image data where the metallic data is stored
				SimplygonSDK::spImageData OutputSpecularData = SDK->CreateImageData();
				// Cast the data using a color caster
				SimplygonSDK::spColorCaster cast = SDK->CreateColorCaster();
				cast->SetColorType( USER_MATERIAL_CHANNEL_SPECULAR );
				cast->SetSourceMaterials( OriginalMaterials );
				cast->SetMappingImage( MappingImage ); 
				cast->SetOutputChannels( 3 );
				cast->SetOutputChannelBitDepth( 8 );
				cast->SetsRGB(false);
				cast->SetDilation( 10 ); 
				cast->SetOutputImage(OutputSpecularData);
				cast->CastMaterials(); // Fetch!

				OutputMaterialLOD->AddUserChannel(USER_MATERIAL_CHANNEL_SPECULAR);
				OutputMaterialLOD->SetLayeredTextureImage(USER_MATERIAL_CHANNEL_SPECULAR, 0, OutputSpecularData);
				OutputMaterialLOD->SetLayeredTextureLevel(USER_MATERIAL_CHANNEL_SPECULAR, 0, 0);
			}
						
			//Create a new material table for the new materials
			SimplygonSDK::spMaterialTable OutputTable = SDK->CreateMaterialTable();
			OutputTable->AddMaterial(OutputMaterialLOD);

			//Convert the simplygon material to unreal materials
			CreateFlattenMaterialFromSGMaterial(OutputTable, OutMaterial);
		}

		//Collect the proxy mesh
		SimplygonSDK::spSceneMesh ProxyMesh = SimplygonSDK::Cast<SimplygonSDK::ISceneMesh>(Scene->GetRootNode()->GetChild(0));

#ifdef DEBUG_PROXY_MESH
		SimplygonSDK::spWavefrontExporter objexp = SDK->CreateWavefrontExporter();
		objexp->SetExportFilePath( "d:/AfterProxyMesh.obj" );
		objexp->SetSingleGeometry( ProxyMesh->GetGeometry() );
		objexp->RunExport();
#endif
	
		//Convert geometry data to raw mesh data
		SimplygonSDK::spGeometryData outGeom = ProxyMesh->GetGeometry();
		CreateRawMeshFromGeometry(OutProxyMesh, ProxyMesh->GetGeometry(), WINDING_Keep);

		// Since mesh proxies have 1 texture channel
		// put copy to channel 1 for lightmaps
		OutProxyMesh.WedgeTexCoords[1].Empty();
		OutProxyMesh.WedgeTexCoords[1].Append(OutProxyMesh.WedgeTexCoords[0]);

		// Default smoothing
		OutProxyMesh.FaceSmoothingMasks.SetNum(OutProxyMesh.FaceMaterialIndices.Num());
		for (uint32& SmoothingMask : OutProxyMesh.FaceSmoothingMasks)
		{
			SmoothingMask = 1;
		}
	}

private:
	SimplygonSDK::ISimplygonSDK* SDK;
	FDefaultErrorHandler ErrorHandler;
	FDefaultEventHandler EventHandler;
	FString VersionString;

	explicit FSimplygonMeshReduction(SimplygonSDK::ISimplygonSDK* InSDK)
		: SDK(InSDK)
	{
		check(SDK);
		SDK->SetErrorHandler(&ErrorHandler);
		SDK->SetGlobalSetting("DefaultTBNType", SimplygonSDK::SG_TANGENTSPACEMETHOD_ORTHONORMAL_LEFTHANDED);

		const TCHAR* LibraryVersion = TEXT("Simplygon_5_5_2156");
		const TCHAR* UnrealVersionGuid = TEXT("18f808c3cf724e5a994f57de5c83cc4b");
		VersionString = FString::Printf(TEXT("%s_%s"), LibraryVersion, UnrealVersionGuid);
	}

	SimplygonSDK::spGeometryData CreateGeometryFromRawMesh(const FRawMesh& RawMesh)
	{
		int32 NumVertices = RawMesh.VertexPositions.Num();
		int32 NumWedges = RawMesh.WedgeIndices.Num();
		int32 NumTris = NumWedges / 3;

		if (NumWedges == 0)
		{
			return NULL;
		}

		SimplygonSDK::spGeometryData GeometryData = SDK->CreateGeometryData();
		GeometryData->SetVertexCount(NumVertices);
		GeometryData->SetTriangleCount(NumTris);

		SimplygonSDK::spRealArray Positions = GeometryData->GetCoords();
		for (int32 VertexIndex = 0; VertexIndex < NumVertices; ++VertexIndex)
		{
			FVector TempPos = RawMesh.VertexPositions[VertexIndex];
			TempPos.Z = -TempPos.Z;
			Positions->SetTuple(VertexIndex, (float*)&TempPos);
		}

		SimplygonSDK::spRidArray Indices = GeometryData->GetVertexIds();
		for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
		{
			Indices->SetItem(WedgeIndex, RawMesh.WedgeIndices[WedgeIndex]);
		}

		for(int32 TexCoordIndex = 0; TexCoordIndex < MAX_MESH_TEXTURE_COORDS; ++TexCoordIndex)
		{
			if (RawMesh.WedgeTexCoords[TexCoordIndex].Num() == NumWedges)
			{
				GeometryData->AddTexCoords(TexCoordIndex);
				SimplygonSDK::spRealArray TexCoords = GeometryData->GetTexCoords(TexCoordIndex);
				check(TexCoords->GetTupleSize() == 2);
				for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
				{
					TexCoords->SetTuple(WedgeIndex, (float*)&RawMesh.WedgeTexCoords[TexCoordIndex][WedgeIndex]);
				}
			}
		}

		if (RawMesh.WedgeColors.Num() == NumWedges)
		{
			GeometryData->AddColors(0);
			SimplygonSDK::spRealArray LinearColors = GeometryData->GetColors(0);
			check(LinearColors);
			check(LinearColors->GetTupleSize() == 4);
			for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
			{
				FLinearColor LinearColor(RawMesh.WedgeColors[WedgeIndex]);
				LinearColors->SetTuple(WedgeIndex, (float*)&LinearColor);
			}
		}

		if (RawMesh.WedgeTangentZ.Num() == NumWedges)
		{
			if (RawMesh.WedgeTangentX.Num() == NumWedges && RawMesh.WedgeTangentY.Num() == NumWedges)
			{
				GeometryData->AddTangents(0);
				SimplygonSDK::spRealArray Tangents = GeometryData->GetTangents(0);
				for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
				{
					FVector TempTangent = RawMesh.WedgeTangentX[WedgeIndex];
					TempTangent.Z = -TempTangent.Z;
					Tangents->SetTuple(WedgeIndex, (float*)&TempTangent);
				}

				GeometryData->AddBitangents(0);
				SimplygonSDK::spRealArray Bitangents = GeometryData->GetBitangents(0);
				for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
				{
					FVector TempBitangent = RawMesh.WedgeTangentY[WedgeIndex];
					TempBitangent.Z = -TempBitangent.Z;
					Bitangents->SetTuple(WedgeIndex, (float*)&TempBitangent);
				}
			}
			GeometryData->AddNormals();
			SimplygonSDK::spRealArray Normals = GeometryData->GetNormals();
			for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
			{
				FVector TempNormal = RawMesh.WedgeTangentZ[WedgeIndex];
				TempNormal.Z = -TempNormal.Z;
				Normals->SetTuple(WedgeIndex, (float*)&TempNormal);
			}
		}

		// Per-triangle data.
		GeometryData->AddMaterialIds();
		SimplygonSDK::spRidArray MaterialIndices = GeometryData->GetMaterialIds();
		for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
		{
			MaterialIndices->SetItem(TriIndex, RawMesh.FaceMaterialIndices[TriIndex]);
		}

		GeometryData->AddGroupIds();
		SimplygonSDK::spRidArray GroupIds = GeometryData->GetGroupIds();
		for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
		{
			GroupIds->SetItem(TriIndex, RawMesh.FaceSmoothingMasks[TriIndex]);
		}
		
		return GeometryData;
	}

	void CreateRawMeshFromGeometry(FRawMesh& OutRawMesh, const SimplygonSDK::spGeometryData& GeometryData, EWindingMode WindingMode)
	{
		check(GeometryData);

		SimplygonSDK::spRealArray Positions = GeometryData->GetCoords();
		SimplygonSDK::spRidArray Indices = GeometryData->GetVertexIds();
		SimplygonSDK::spRidArray MaterialIndices = GeometryData->GetMaterialIds();
		SimplygonSDK::spRidArray GroupIds = GeometryData->GetGroupIds();
		SimplygonSDK::spRealArray LinearColors = GeometryData->GetColors(0);
		SimplygonSDK::spRealArray Normals = GeometryData->GetNormals();
		SimplygonSDK::spRealArray Tangents = GeometryData->GetTangents(0);
		SimplygonSDK::spRealArray Bitangents = GeometryData->GetBitangents(0);

		check(Positions);
		check(Indices);

		FRawMesh& RawMesh = OutRawMesh;
		const bool bReverseWinding = (WindingMode == WINDING_Reverse);
		int32 NumTris = GeometryData->GetTriangleCount();
		int32 NumWedges = NumTris * 3;
		int32 NumVertices = GeometryData->GetVertexCount();

		RawMesh.VertexPositions.Empty(NumVertices);
		RawMesh.VertexPositions.AddUninitialized(NumVertices);
		for (int32 VertexIndex = 0; VertexIndex < NumVertices; ++VertexIndex)
		{
			Positions->GetTuple(VertexIndex, (float*)&RawMesh.VertexPositions[VertexIndex]);
			RawMesh.VertexPositions[VertexIndex].Z = -RawMesh.VertexPositions[VertexIndex].Z;
		}

		RawMesh.WedgeIndices.Empty(NumWedges);
		RawMesh.WedgeIndices.AddUninitialized(NumWedges);
		for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
		{
			for (int32 CornerIndex = 0; CornerIndex < 3; ++CornerIndex)
			{
				const uint32 DestIndex = bReverseWinding ? (2 - CornerIndex) : CornerIndex;
				RawMesh.WedgeIndices[TriIndex * 3 + DestIndex] = Indices->GetItem(TriIndex * 3 + CornerIndex);
			}
		}

		for(int32 TexCoordIndex = 0; TexCoordIndex < MAX_MESH_TEXTURE_COORDS; ++TexCoordIndex)
		{
			SimplygonSDK::spRealArray TexCoords = GeometryData->GetTexCoords(TexCoordIndex);
			if (TexCoords)
			{
				RawMesh.WedgeTexCoords[TexCoordIndex].Empty(NumWedges);
				RawMesh.WedgeTexCoords[TexCoordIndex].AddUninitialized(NumWedges);
				for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
				{
					for (int32 CornerIndex = 0; CornerIndex < 3; ++CornerIndex)
					{
						const uint32 DestIndex = bReverseWinding ? (2 - CornerIndex) : CornerIndex;
						TexCoords->GetTuple(TriIndex * 3 + CornerIndex, (float*)&RawMesh.WedgeTexCoords[TexCoordIndex][TriIndex * 3 + DestIndex]);
					}
				}
			}
		}

		if (LinearColors)
		{
			RawMesh.WedgeColors.Empty(NumWedges);
			RawMesh.WedgeColors.AddUninitialized(NumWedges);
			for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
			{
				FLinearColor LinearColor;
				LinearColors->GetTuple(WedgeIndex, (float*)&LinearColor);
				RawMesh.WedgeColors[WedgeIndex] = LinearColor.ToFColor(true);
			}
		}

		if (Normals)
		{
			if (Tangents && Bitangents)
			{
				RawMesh.WedgeTangentX.Empty(NumWedges);
				RawMesh.WedgeTangentX.AddUninitialized(NumWedges);
				for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
				{
					Tangents->GetTuple(WedgeIndex, (float*)&RawMesh.WedgeTangentX[WedgeIndex]);
					RawMesh.WedgeTangentX[WedgeIndex].Z = -RawMesh.WedgeTangentX[WedgeIndex].Z;
				}

				RawMesh.WedgeTangentY.Empty(NumWedges);
				RawMesh.WedgeTangentY.AddUninitialized(NumWedges);
				for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
				{
					Bitangents->GetTuple(WedgeIndex, (float*)&RawMesh.WedgeTangentY[WedgeIndex]);
					RawMesh.WedgeTangentY[WedgeIndex].Z = -RawMesh.WedgeTangentY[WedgeIndex].Z;
				}
			}

			RawMesh.WedgeTangentZ.Empty(NumWedges);
			RawMesh.WedgeTangentZ.AddUninitialized(NumWedges);
			for (int32 WedgeIndex = 0; WedgeIndex < NumWedges; ++WedgeIndex)
			{
				Normals->GetTuple(WedgeIndex, (float*)&RawMesh.WedgeTangentZ[WedgeIndex]);
				RawMesh.WedgeTangentZ[WedgeIndex].Z = -RawMesh.WedgeTangentZ[WedgeIndex].Z;
			}
		}

		RawMesh.FaceMaterialIndices.Empty(NumTris);
		RawMesh.FaceMaterialIndices.AddZeroed(NumTris);
		if (MaterialIndices)
		{
			for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
			{
				RawMesh.FaceMaterialIndices[TriIndex] = MaterialIndices->GetItem(TriIndex);
			}
		}

		RawMesh.FaceSmoothingMasks.Empty(NumTris);
		RawMesh.FaceSmoothingMasks.AddZeroed(NumTris);
		if (GroupIds)
		{
			for (int32 TriIndex = 0; TriIndex < NumTris; ++TriIndex)
			{
				RawMesh.FaceSmoothingMasks[TriIndex] = GroupIds->GetItem(TriIndex);
			}
		}
	}

	void SetReductionSettings(SimplygonSDK::spReductionSettings ReductionSettings, const FMeshReductionSettings& Settings, int32 NumTris)
	{
		float MaxDeviation = Settings.MaxDeviation > 0.0f ? Settings.MaxDeviation : FLT_MAX;
		float MinReductionRatio = FMath::Max<float>(1.0f / NumTris, 0.05f);
		float MaxReductionRatio = (Settings.MaxDeviation > 0.0f && Settings.PercentTriangles == 1.0f) ? MinReductionRatio : 1.0f;
		float ReductionRatio = FMath::Clamp(Settings.PercentTriangles, MinReductionRatio, MaxReductionRatio);

		unsigned int FeatureFlagsMask = SimplygonSDK::SG_FEATUREFLAGS_GROUP;
		if (Settings.TextureImportance != EMeshFeatureImportance::Off)
		{
			FeatureFlagsMask |= (SimplygonSDK::SG_FEATUREFLAGS_TEXTURE0 | SimplygonSDK::SG_FEATUREFLAGS_MATERIAL);
		}
		if (Settings.ShadingImportance != EMeshFeatureImportance::Off)
		{
			FeatureFlagsMask |= SimplygonSDK::SG_FEATUREFLAGS_SHADING;
		}

		const float ImportanceTable[] =
		{
			0.0f,	// OFF
			0.125f,	// Lowest
			0.35f,	// Low,
			1.0f,	// Normal
			2.8f,	// High
			8.0f,	// Highest
		};

		static_assert(ARRAY_COUNT(ImportanceTable) == (EMeshFeatureImportance::Highest + 1), "Importance table size mismatch."); // -1 because of TEMP_BROKEN(?)
		check(Settings.SilhouetteImportance < EMeshFeatureImportance::Highest+1); // -1 because of TEMP_BROKEN(?)
		check(Settings.TextureImportance < EMeshFeatureImportance::Highest+1); // -1 because of TEMP_BROKEN(?)
		check(Settings.ShadingImportance < EMeshFeatureImportance::Highest+1); // -1 because of TEMP_BROKEN(?)

		ReductionSettings->SetFeatureFlags(FeatureFlagsMask);
		ReductionSettings->SetMaxDeviation(MaxDeviation);
		ReductionSettings->SetReductionRatio(ReductionRatio);
		ReductionSettings->SetGeometryImportance(ImportanceTable[Settings.SilhouetteImportance]);
		ReductionSettings->SetTextureImportance(ImportanceTable[Settings.TextureImportance]);
		ReductionSettings->SetMaterialImportance(ImportanceTable[Settings.TextureImportance]);
		ReductionSettings->SetShadingImportance( ImportanceTable[Settings.ShadingImportance]);
		ReductionSettings->SetAllowDirectX(false);
	}

	void SetNormalSettings(SimplygonSDK::spNormalCalculationSettings NormalSettings, const FMeshReductionSettings& Settings)
	{
		NormalSettings->SetReplaceNormals(Settings.bRecalculateNormals);
		NormalSettings->SetScaleByArea(false);
		NormalSettings->SetScaleByAngle(false);
		NormalSettings->SetHardEdgeAngle(Settings.HardAngleThreshold);
	}

	/**
	 * Creates a Simplygon scene representation of the skeletal hierarchy.
	 * @param InScene - The Simplygon scene.
	 * @param InSkeleton - The skeletal hierarchy from which to create the Simplygon representation.
	 * @param OutBoneTableIDs - A mapping of Bone IDs from RefSkeleton to Simplygon Bone Table IDs
	 */
	void CreateSkeletalHierarchy( SimplygonSDK::spScene& InScene, const FReferenceSkeleton& InSkeleton, TArray<SimplygonSDK::rid>& OutBoneTableIDs ) 
	{
		TArray<SimplygonSDK::spSceneBone> BoneArray;
		
		//Create Simplygon scene nodes for each bone in our Skeletal Hierarchy
		for(int32 BoneIndex=0; BoneIndex < InSkeleton.GetNum(); ++BoneIndex)
		{	
			SimplygonSDK::spSceneBone SceneBone = SDK->CreateSceneBone();
			BoneArray.Add(SceneBone);
		}

		SimplygonSDK::spSceneBoneTable BoneTable = InScene->GetBoneTable();
		for(int32 BoneIndex=0; BoneIndex < InSkeleton.GetNum(); ++BoneIndex)
		{
			int32 ParentIndex = InSkeleton.GetParentIndex(BoneIndex);
			SimplygonSDK::spSceneBone CurrentBone = BoneArray[BoneIndex];

			//We add the bone to the scene's bone table. This returns a uid that we must apply to the geometry data.
			SimplygonSDK::rid BoneID = BoneTable->AddBone(CurrentBone);
			OutBoneTableIDs.Add(BoneID);

			//Handle root bone. Add to Scene root.
			if(BoneIndex == 0)
			{
				InScene->GetRootNode()->AddChild(CurrentBone);
			} 
			else
			{
				SimplygonSDK::spSceneBone ParentBone = BoneArray[ParentIndex];
				ParentBone->AddChild(CurrentBone);
			}
		}
	}

	/**
	 * Creates a Simplygon geometry representation from a skeletal mesh LOD model.
	 * @param Scene - The Simplygon scene.
	 * @param LODModel - The skeletal mesh LOD model from which to create the geometry data.
	 * @param BoneIDs - A maps of Bone IDs from RefSkeleton to Simplygon BoneTable IDs
	 * @returns a Simplygon geometry data representation of the skeletal mesh LOD.
	 */
	SimplygonSDK::spGeometryData CreateGeometryFromSkeletalLODModel( SimplygonSDK::spScene& Scene, const FStaticLODModel& LODModel, const TArray<SimplygonSDK::rid>& BoneIDs )
	{
		TArray<FSoftSkinVertex> Vertices;
		FMultiSizeIndexContainerData IndexData;
		LODModel.GetVertices( Vertices );
		LODModel.MultiSizeIndexContainer.GetIndexBufferData( IndexData );

		const uint32 VertexCount = LODModel.NumVertices;
		const uint32 TexCoordCount = LODModel.NumTexCoords;
		check( TexCoordCount <= MAX_TEXCOORDS );

		uint32 TriCount = 0;
#if WITH_APEX_CLOTHING
		const uint32 SectionCount = (uint32)LODModel.NumNonClothingSections();
#else
		const uint32 SectionCount = LODModel.Sections.Num();
#endif // #if WITH_APEX_CLOTHING
		for ( uint32 SectionIndex = 0; SectionIndex < SectionCount; ++SectionIndex )
		{
			TriCount += LODModel.Sections[ SectionIndex ].NumTriangles;
		}

		SimplygonSDK::spGeometryData GeometryData = SDK->CreateGeometryData();
		GeometryData->SetVertexCount( VertexCount );
		GeometryData->SetTriangleCount( TriCount );

		// Per-vertex data.
		GeometryData->AddBoneIds( MAX_TOTAL_INFLUENCES );
		GeometryData->AddBoneWeights( MAX_TOTAL_INFLUENCES );
		SimplygonSDK::spRealArray Positions = GeometryData->GetCoords();
		SimplygonSDK::spRidArray BoneIds = GeometryData->GetBoneIds();
		SimplygonSDK::spRealArray BoneWeights = GeometryData->GetBoneWeights();

		// Per-corner per-triangle data.
		SimplygonSDK::spRidArray Indices = GeometryData->GetVertexIds();
		SimplygonSDK::spRealArray TexCoords[MAX_TEXCOORDS];
		for( uint32 TexCoordIndex = 0; TexCoordIndex < TexCoordCount; ++TexCoordIndex )
		{
			GeometryData->AddTexCoords( TexCoordIndex );
			TexCoords[TexCoordIndex] = GeometryData->GetTexCoords( TexCoordIndex );
			check( TexCoords[TexCoordIndex]->GetTupleSize() == 2 );
		}
		GeometryData->AddNormals();
		GeometryData->AddTangents(0);
		GeometryData->AddBitangents(0);
		SimplygonSDK::spRealArray Normals = GeometryData->GetNormals();
		SimplygonSDK::spRealArray Tangents = GeometryData->GetTangents(0);
		SimplygonSDK::spRealArray Bitangents = GeometryData->GetBitangents(0);

		SimplygonSDK::spUnsignedCharArray Colors;
		if ( LODModel.ColorVertexBuffer.GetNumVertices() == VertexCount )
		{
			GeometryData->AddBaseTypeUserTriangleVertexField( SimplygonSDK::TYPES_ID_UCHAR, SIMPLYGON_COLOR_CHANNEL, 4 );
			SimplygonSDK::spValueArray ColorValues = GeometryData->GetUserTriangleVertexField( SIMPLYGON_COLOR_CHANNEL );
			check( ColorValues );
			Colors = SimplygonSDK::IUnsignedCharArray::SafeCast( ColorValues );
			check( Colors );
		}

		// Per-triangle data.
		GeometryData->AddMaterialIds();
		SimplygonSDK::spRidArray MaterialIndices = GeometryData->GetMaterialIds();

		// Add per-vertex data. This data needs to be added per-chunk so that we can properly map bones.
#if WITH_APEX_CLOTHING
		const int32 ChunkCount = LODModel.NumNonClothingSections();
#else
		const int32 ChunkCount = LODModel.Chunks.Num();
#endif // #if WITH_APEX_CLOTHING
		uint32 FirstVertex = 0;
		for ( int32 ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex )
		{
			const FSkelMeshChunk& Chunk = LODModel.Chunks[ ChunkIndex ];
			const uint32 LastVertex = FirstVertex + (uint32)Chunk.RigidVertices.Num() + (uint32)Chunk.SoftVertices.Num();
			for ( uint32 VertexIndex = FirstVertex; VertexIndex < LastVertex; ++VertexIndex )
			{
				FSoftSkinVertex& Vertex = Vertices[ VertexIndex ];
				SimplygonSDK::rid VertexBoneIds[MAX_TOTAL_INFLUENCES];
				SimplygonSDK::real VertexBoneWeights[MAX_TOTAL_INFLUENCES];

				uint32 TotalInfluence = 0;
				for ( uint32 InfluenceIndex = 0; InfluenceIndex < MAX_TOTAL_INFLUENCES; ++InfluenceIndex )
				{
					int32 BoneIndex = Vertex.InfluenceBones[InfluenceIndex];
					const uint8 BoneInfluence = Vertex.InfluenceWeights[InfluenceIndex];
					TotalInfluence += BoneInfluence;

					if ( BoneInfluence > 0 )
					{
						check( BoneIndex < Chunk.BoneMap.Num() );
						uint32 BoneID = BoneIDs[ Chunk.BoneMap[ BoneIndex ] ];
						VertexBoneIds[InfluenceIndex] = BoneID;
						VertexBoneWeights[InfluenceIndex] = BoneInfluence / 255.0f;
					}
					else
					{
						//Set BoneID and BoneWeight to -1 and 0 respectively as required by simplygon.
						VertexBoneIds[InfluenceIndex] = -1;
						VertexBoneWeights[InfluenceIndex] = 0;
					}
				}
				check( TotalInfluence == 255 );

				Positions->SetTuple( VertexIndex, (float*)&Vertex.Position );
				BoneIds->SetTuple( VertexIndex, VertexBoneIds );
				BoneWeights->SetTuple( VertexIndex, VertexBoneWeights );
			}
			FirstVertex = LastVertex;
		}

		// Add per-vertex per-triangle data.
		for ( uint32 SectionIndex = 0; SectionIndex < SectionCount; ++SectionIndex )
		{
			const FSkelMeshSection& Section = LODModel.Sections[ SectionIndex ];
			const uint32 FirstIndex = Section.BaseIndex;
			const uint32 LastIndex = FirstIndex + Section.NumTriangles * 3;

			for ( uint32 Index = FirstIndex; Index < LastIndex; ++Index )
			{
				uint32 VertexIndex = IndexData.Indices[ Index ];
				FSoftSkinVertex& Vertex = Vertices[ VertexIndex ];

				FVector Normal = Vertex.TangentZ;
				FVector Tangent = Vertex.TangentX;
				FVector Bitangent = Vertex.TangentY;

				Indices->SetItem( Index, VertexIndex );
				Normals->SetTuple( Index, (float*)&Normal );
				Tangents->SetTuple( Index, (float*)&Tangent );
				Bitangents->SetTuple( Index, (float*)&Bitangent );

				for( uint32 TexCoordIndex = 0; TexCoordIndex < TexCoordCount; ++TexCoordIndex )
				{
					FVector2D TexCoord = Vertex.UVs[TexCoordIndex];
					TexCoords[TexCoordIndex]->SetTuple( Index, (float*)&TexCoord );
				}

				if ( Colors )
				{
					FColor Color = LODModel.ColorVertexBuffer.VertexColor( VertexIndex );
					Colors->SetTuple( Index, (UCHAR*)&Color );
				}
			}
		}

		// Add per-triangle data.
		for ( uint32 SectionIndex = 0; SectionIndex < SectionCount; ++SectionIndex )
		{
			const FSkelMeshSection& Section = LODModel.Sections[ SectionIndex ];
			const uint32 FirstTriIndex = Section.BaseIndex / 3;
			const uint32 LastTriIndex = FirstTriIndex + Section.NumTriangles - 1;
			const uint16 MaterialIndex = Section.MaterialIndex;
			for ( uint32 TriIndex = FirstTriIndex; TriIndex <= LastTriIndex; ++TriIndex )
			{
				MaterialIndices->SetItem( TriIndex, MaterialIndex );
				check( MaterialIndices->GetItem( TriIndex) == MaterialIndex );
			}
		}

		// Create a new simplygon scene mesh object
		SimplygonSDK::spSceneMesh Mesh = SDK->CreateSceneMesh();

		// Assign the geometry data to the mesh
		Mesh->SetGeometry( GeometryData );

		// Add Mesh to the scene
		Scene->GetRootNode()->AddChild( Mesh );

		return GeometryData;
	}

	/**
	 * Holds data needed to create skeletal mesh skinning streams.
	 */
	struct FSkeletalMeshData
	{
		TArray<FVertInfluence> Influences;
		TArray<FMeshWedge> Wedges;
		TArray<FMeshFace> Faces;
		TArray<FVector> Points;
		uint32 TexCoordCount;
	};

	/**
	 * Extracts mesh data from the Simplygon geometry representation in to a set of data usable by skeletal meshes.
	 * @param GeometryData - the Simplygon geometry.
	 * @param MeshData - the skeletal mesh output data.
	 */
	void ExtractSkeletalDataFromGeometry( const SimplygonSDK::spGeometryData& GeometryData, FSkeletalMeshData& MeshData )
	{
		TArray<FVector> PointNormals;
		TArray<uint32> PointList;
		TArray<uint32> PointInfluenceMap;

		check( GeometryData );

		SimplygonSDK::spRealArray Positions = GeometryData->GetCoords();
		SimplygonSDK::spRidArray Indices = GeometryData->GetVertexIds();
		SimplygonSDK::spRidArray MaterialIndices = GeometryData->GetMaterialIds();
		SimplygonSDK::spValueArray VertexColorValues = GeometryData->GetUserTriangleVertexField( SIMPLYGON_COLOR_CHANNEL );
		SimplygonSDK::spUnsignedCharArray VertexColors = SimplygonSDK::IUnsignedCharArray::SafeCast( VertexColorValues );
		SimplygonSDK::spRealArray Normals = GeometryData->GetNormals();
		SimplygonSDK::spRealArray Tangents = GeometryData->GetTangents(0);
		SimplygonSDK::spRealArray Bitangents = GeometryData->GetBitangents(0);
		SimplygonSDK::spRidArray BoneIds = GeometryData->GetBoneIds();
		SimplygonSDK::spRealArray BoneWeights = GeometryData->GetBoneWeights();
		SimplygonSDK::spRealArray TexCoords[MAX_TEXCOORDS];
		uint32 TexCoordCount = 0;
		for( uint32 TexCoordIndex = 0; TexCoordIndex < MAX_TEXCOORDS; ++TexCoordIndex )
		{
			TexCoords[TexCoordIndex] = GeometryData->GetTexCoords(TexCoordIndex);
			if ( TexCoords[TexCoordIndex] == NULL )
			{
				break;
			}
			TexCoordCount++;
		}
		MeshData.TexCoordCount = TexCoordCount;

		check( Positions );
		check( Indices );
		check( MaterialIndices );
		check( Normals );
		check( Tangents );
		check( Bitangents );
		check( BoneIds );
		check( BoneWeights );

		const bool bHaveColors = (VertexColors != NULL);
		const uint32 VertexCount = GeometryData->GetVertexCount();
		const uint32 TriCount = GeometryData->GetTriangleCount();

		// Initialize the lists of points, wedges, and faces.
		MeshData.Points.AddZeroed( VertexCount );
		PointNormals.AddZeroed( VertexCount );
		PointList.Reserve( VertexCount );
		PointInfluenceMap.Reserve( VertexCount );
		for ( uint32 PointIndex = 0; PointIndex < VertexCount; ++PointIndex )
		{
			PointList.Add( INDEX_NONE );
			PointInfluenceMap.Add( INDEX_NONE );
		}
		MeshData.Wedges.AddZeroed( TriCount * 3 );
		MeshData.Faces.AddZeroed( TriCount );
		
		//The number of influences may have changed if we have specified a max number of bones per vertex.
		uint32 NumOfInfluences = FMath::Min<uint32>( BoneIds->GetTupleSize() , MAX_TOTAL_INFLUENCES );

		// Per-vertex data.
		for ( uint32 VertexIndex = 0; VertexIndex < VertexCount; ++VertexIndex )
		{
			FVector& Point = MeshData.Points[ VertexIndex ];
			SimplygonSDK::rid VertexBoneIds[MAX_TOTAL_INFLUENCES];
			SimplygonSDK::real VertexBoneWeights[MAX_TOTAL_INFLUENCES];
			Positions->GetTuple( VertexIndex, (float*)&Point );
			BoneIds->GetTuple( VertexIndex, VertexBoneIds );
			BoneWeights->GetTuple( VertexIndex, VertexBoneWeights );
			PointInfluenceMap[ VertexIndex ] = (uint32)MeshData.Influences.Num();
			for ( uint32 InfluenceIndex = 0; InfluenceIndex < NumOfInfluences; ++InfluenceIndex )
			{
				const uint16 BoneIndex = VertexBoneIds[InfluenceIndex];
				const float BoneWeight = VertexBoneWeights[InfluenceIndex];
				if ( InfluenceIndex == 0 || BoneWeight > 0.0f )
				{
					FVertInfluence* VertInfluence = new(MeshData.Influences) FVertInfluence;
					VertInfluence->BoneIndex = BoneIndex;
					VertInfluence->Weight = BoneWeight;
					VertInfluence->VertIndex = VertexIndex;
				}
			}
		}

		// Per-triangle and per-corner data.
		for ( uint32 TriIndex = 0; TriIndex < TriCount; ++TriIndex )
		{
			// Per-triangle data.
			FMeshFace& Face = MeshData.Faces[ TriIndex ];
			Face.MeshMaterialIndex = MaterialIndices->GetItem( TriIndex );

			// Per-corner data.
			for( uint32 CornerIndex = 0; CornerIndex < 3; ++CornerIndex )
			{
				const uint32 WedgeIndex = TriIndex * 3 + CornerIndex;
				const uint32 BasePointIndex = (uint32)Indices->GetItem( WedgeIndex );
				uint32 PointIndex = BasePointIndex;

				check( BasePointIndex < (uint32)PointList.Num() );

				// Duplicate points where needed to create hard edges.
				FVector WedgeNormal;
				Normals->GetTuple( WedgeIndex, (float*)&WedgeNormal );
				WedgeNormal.Normalize();
				FVector PointNormal = PointNormals[ PointIndex ];
				if ( PointNormal.SizeSquared() < KINDA_SMALL_NUMBER )
				{
					PointNormals[ PointIndex ] = WedgeNormal;
				}
				else
				{
					while ( (PointNormal | WedgeNormal) - 1.0f < -KINDA_SMALL_NUMBER )
					{
						PointIndex = PointList[ PointIndex ];
						if ( PointIndex == INDEX_NONE )
						{
							break;
						}
						check( PointIndex < (uint32)PointList.Num() );
						PointNormal = PointNormals[ PointIndex ];
					}

					if ( PointIndex == INDEX_NONE )
					{
						FVector Point = MeshData.Points[ BasePointIndex ];
						PointIndex = MeshData.Points.Add( Point );
						check( PointIndex == (uint32)PointList.Num() );
						check( PointIndex == (uint32)PointInfluenceMap.Num() );
						check( PointIndex == (uint32)PointNormals.Num() );
						PointNormals.Add( WedgeNormal );
						uint32 NextPointIndex = PointList[ BasePointIndex ];
						check( NextPointIndex < (uint32)PointList.Num() || NextPointIndex == INDEX_NONE );
						PointList[ BasePointIndex ] = PointIndex;
						PointList.Add( NextPointIndex );
						PointInfluenceMap.Add( (uint32)MeshData.Influences.Num() );

						int32 InfluenceIndex = PointInfluenceMap[ BasePointIndex ];
						while ( MeshData.Influences[ InfluenceIndex ].VertIndex == BasePointIndex )
						{
							FVertInfluence* NewVertInfluence = new( MeshData.Influences ) FVertInfluence;
							NewVertInfluence->BoneIndex = MeshData.Influences[ InfluenceIndex ].BoneIndex;
							NewVertInfluence->Weight = MeshData.Influences[ InfluenceIndex ].Weight;
							NewVertInfluence->VertIndex = PointIndex;
							InfluenceIndex++;
						}

						check( PointNormals.Num() == MeshData.Points.Num() );
						check( PointList.Num() == MeshData.Points.Num() );
						check( PointInfluenceMap.Num() == MeshData.Points.Num() );
					}
				}

				check( PointIndex != INDEX_NONE );
				check( ( MeshData.Points[ PointIndex ] - MeshData.Points[ BasePointIndex ] ).SizeSquared() == 0.0f );

				FMeshWedge& Wedge = MeshData.Wedges[ WedgeIndex ];
				Wedge.iVertex = PointIndex;
				for( uint32 TexCoordIndex = 0; TexCoordIndex < TexCoordCount; ++TexCoordIndex )
				{
					TexCoords[TexCoordIndex]->GetTuple( WedgeIndex, (float*)&Wedge.UVs[TexCoordIndex] );
				}

				if( bHaveColors )
				{
					VertexColors->GetTuple( WedgeIndex, (uint8 *)&Wedge.Color );
				}
				else
				{
					Wedge.Color = FColor( 255, 255, 255, 255 );
				}

				Face.iWedge[CornerIndex] = WedgeIndex;
			}
		}
	}

	/**
	 * Creates a skeletal mesh LOD model from the Simplygon geometry representation.
	 * @param GeometryData - the Simplygon geometry representation from which to create a skeletal mesh LOD.
	 * @param SkeletalMesh - the skeletal mesh in to which the LOD model will be added.
	 * @param NewModel - the LOD model in to which the geometry will be stored.
	 */
	void CreateSkeletalLODModelFromGeometry( const SimplygonSDK::spGeometryData& GeometryData, const FReferenceSkeleton& RefSkeleton, FStaticLODModel* NewModel )
	{
		check( GeometryData );

		FSkeletalMeshData MeshData;
		ExtractSkeletalDataFromGeometry( GeometryData, MeshData );

		// Create dummy map of 'point to original'
		TArray<int32> DummyMap;
		DummyMap.AddUninitialized(MeshData.Points.Num());
		for(int32 PointIdx = 0; PointIdx<MeshData.Points.Num(); PointIdx++)
		{
			DummyMap[PointIdx] = PointIdx;
		}

		IMeshUtilities& MeshUtilities = FModuleManager::Get().LoadModuleChecked<IMeshUtilities>("MeshUtilities");
		// Create skinning streams for NewModel.
		MeshUtilities.BuildSkeletalMesh( 
			*NewModel,
			RefSkeleton,
			MeshData.Influences, 
			MeshData.Wedges, 
			MeshData.Faces, 
			MeshData.Points,
			DummyMap
			);

		// Set texture coordinate count on the new model.
		NewModel->NumTexCoords = MeshData.TexCoordCount;
		NewModel->Size = 0;
	}

	/**
	 * Sets reduction settings for Simplygon.
	 * @param Settings - The skeletal mesh optimization settings.
	 * @param ReductionSettings - The reduction settings to set for Simplygon.
	 */
	void SetReductionSettings( const FSkeletalMeshOptimizationSettings& Settings, float BoundsRadius, int32 SourceTriCount, SimplygonSDK::spReductionSettings ReductionSettings )
	{
		// Compute max deviation from quality.
		float MaxDeviation = Settings.MaxDeviationPercentage > 0.0f ? Settings.MaxDeviationPercentage * BoundsRadius : SimplygonSDK::REAL_MAX;
		// Set the reduction ratio such that at least 1 triangle or 5% of the original triangles remain, whichever is larger.
		float MinReductionRatio = FMath::Max<float>(1.0f / SourceTriCount, 0.05f);
		float MaxReductionRatio = (Settings.MaxDeviationPercentage > 0.0f && Settings.NumOfTrianglesPercentage == 1.0f) ? MinReductionRatio : 1.0f;
		float ReductionRatio = FMath::Clamp(Settings.NumOfTrianglesPercentage, MinReductionRatio, MaxReductionRatio);

		//Enable feature flags for those features where we have set an importance
		unsigned int FeatureFlagsMask = SimplygonSDK::SG_FEATUREFLAGS_GROUP;
		if( Settings.TextureImportance != SMOI_Off )
		{
			FeatureFlagsMask |= (SimplygonSDK::SG_FEATUREFLAGS_TEXTURE0 | SimplygonSDK::SG_FEATUREFLAGS_MATERIAL);
		}
		if( Settings.ShadingImportance != SMOI_Off )
		{
			FeatureFlagsMask |= SimplygonSDK::SG_FEATUREFLAGS_SHADING;
		}

		const float ImportanceTable[] =
		{
			0.0f,	// OFF
			0.125f,	// Lowest
			0.35f,	// Low,
			1.0f,	// Normal
			2.8f,	// High
			8.0f,	// Highest
		};

		static_assert(ARRAY_COUNT(ImportanceTable) == SMOI_MAX, "Bad importance table size.");
		check( Settings.SilhouetteImportance < SMOI_MAX );
		check( Settings.TextureImportance < SMOI_MAX );
		check( Settings.ShadingImportance < SMOI_MAX );
		check( Settings.SkinningImportance < SMOI_MAX );
		
		ReductionSettings->SetFeatureFlags( FeatureFlagsMask );
		ReductionSettings->SetMaxDeviation( MaxDeviation );
		ReductionSettings->SetReductionRatio( ReductionRatio );
		ReductionSettings->SetGeometryImportance( ImportanceTable[Settings.SilhouetteImportance] );
		ReductionSettings->SetTextureImportance( ImportanceTable[Settings.TextureImportance] );
		ReductionSettings->SetMaterialImportance( ImportanceTable[Settings.TextureImportance] );
		ReductionSettings->SetShadingImportance( ImportanceTable[Settings.ShadingImportance] );
		ReductionSettings->SetSkinningImportance( ImportanceTable[Settings.SkinningImportance] );
	}

	/**
	 * Sets vertex normal settings for Simplygon.
	 * @param Settings - The skeletal mesh optimization settings.
	 * @param NormalSettings - The normal settings to set for Simplygon.
	 */
	void SetNormalSettings( const FSkeletalMeshOptimizationSettings& Settings, SimplygonSDK::spNormalCalculationSettings NormalSettings )
	{
		NormalSettings->SetReplaceNormals( Settings.bRecalcNormals );
		NormalSettings->SetScaleByArea( false );
		NormalSettings->SetScaleByAngle( false );
		NormalSettings->SetHardEdgeAngle( Settings.NormalsThreshold );
	}

	/**
	 * Sets Bone Lod settings for Simplygon.
	 * @param Settings - The skeletal mesh optimization settings.
	 * @param NormalSettings - The Bone LOD to set for Simplygon.
	 */
	void SetBoneSettings( const FSkeletalMeshOptimizationSettings& Settings, SimplygonSDK::spBoneSettings BoneSettings)
	{
		BoneSettings->SetBoneLodProcess( SimplygonSDK::SG_BONEPROCESSING_RATIO_PROCESSING );
		BoneSettings->SetBoneLodRatio ( Settings.BoneReductionRatio );
		BoneSettings->SetMaxBonePerVertex( Settings.MaxBonesPerVertex );
	}

	/**
	 * Calculates the view distance that a mesh should be displayed at.
	 * @param MaxDeviation - The maximum surface-deviation between the reduced geometry and the original. This value should be acquired from Simplygon
	 * @returns The calculated view distance	 
	 */
	float CalculateViewDistance( float MaxDeviation )
	{
		// We want to solve for the depth in world space given the screen space distance between two pixels
		//
		// Assumptions:
		//   1. There is no scaling in the view matrix.
		//   2. The horizontal FOV is 90 degrees.
		//   3. The backbuffer is 1920x1080.
		//
		// If we project two points at (X,Y,Z) and (X',Y,Z) from view space, we get their screen
		// space positions: (X/Z, Y'/Z) and (X'/Z, Y'/Z) where Y' = Y * AspectRatio.
		//
		// The distance in screen space is then sqrt( (X'-X)^2/Z^2 + (Y'-Y')^2/Z^2 )
		// or (X'-X)/Z. This is in clip space, so PixelDist = 1280 * 0.5 * (X'-X)/Z.
		//
		// Solving for Z: ViewDist = (X'-X * 640) / PixelDist

		const float ViewDistance = (MaxDeviation * 960.0f);
		return ViewDistance;
	}

	/**
	 * ProxyLOD Related Methods
	 */
	void SetMaterialChannelData(
		const TArray<FColor>& InSamples, 
		FIntPoint InTextureSize,
		SimplygonSDK::spMaterial& InSGMaterial, 
		const char* SGMaterialChannelName)
	{
		int32 NumTexels = InTextureSize.X * InTextureSize.Y;
		check(NumTexels == InSamples.Num())

		if (NumTexels > 1)
		{
			SimplygonSDK::spImageData ImageData = SDK->CreateImageData();
			ImageData->AddColors(SimplygonSDK::TYPES_ID_UCHAR, SimplygonSDK::SG_IMAGEDATA_FORMAT_RGBA);
			ImageData->Set2DSize(InTextureSize.X, InTextureSize.Y);
			SimplygonSDK::spUnsignedCharArray ImageColors = SimplygonSDK::SafeCast<SimplygonSDK::IUnsignedCharArray>(ImageData->GetColors());
				
			//Set the texture data to simplygon color data texel per texel
			ImageColors->SetTupleCount(NumTexels);
			for (int32 TexelIndex = 0; TexelIndex < NumTexels; TexelIndex++)
			{
				// BGRA -> RGBA
				uint8 Texel[4]; 
				Texel[0] = InSamples[TexelIndex].R;
				Texel[1] = InSamples[TexelIndex].G;
				Texel[2] = InSamples[TexelIndex].B;
				Texel[3] = (SGMaterialChannelName == SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE ? InSamples[TexelIndex].A : FColor::White.A);
			
				ImageColors->SetTuple(TexelIndex, Texel);
			}
			InSGMaterial->SetLayeredTextureImage(SGMaterialChannelName, 0, ImageData);
			InSGMaterial->SetLayeredTextureLevel(SGMaterialChannelName, 0, 0);
		}
		else if (NumTexels == 1)
		{
			// handle uniform value
			InSGMaterial->SetColorRGB(SGMaterialChannelName, InSamples[0].R, InSamples[0].G, InSamples[0].B);
		}
	}

	//Material conversions
	bool CreateSGMaterialFromFlattenMaterial(
		const TArray<MaterialExportUtils::FFlattenMaterial>& InputMaterials,
		SimplygonSDK::spMaterialTable& OutSGMaterialTable, 
		FMaterialCastingProperties& OutCastProperties)
	{
		if (InputMaterials.Num() == 0)
		{
			//If there are no materials, feed Simplygon with a default material instead.
			UE_LOG(LogSimplygon, Log, TEXT("Input meshes do not contain any materials. A proxy without material will be generated."));
			return false;
		}
			
		for (int32 MaterialIndex = 0; MaterialIndex < InputMaterials.Num(); MaterialIndex++)
		{
			SimplygonSDK::spMaterial SGMaterial = SDK->CreateMaterial();
			const MaterialExportUtils::FFlattenMaterial& FlattenMaterial = InputMaterials[MaterialIndex];

			//Create UE4 Channels
			//Simplygon 5.5 has three new channels already present called base color metallic roughness
			//To conform with older simplygon versions:
			if(!SGMaterial->HasUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_BASECOLOR))
				SGMaterial->AddUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_BASECOLOR);

			if(!SGMaterial->HasUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_METALLIC))
				SGMaterial->AddUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_METALLIC);

			if(!SGMaterial->HasUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_ROUGHNESS))
				SGMaterial->AddUserChannel(SimplygonSDK::SG_MATERIAL_CHANNEL_ROUGHNESS);

			// We actually use these channels for metallic, roughness and specular
			if(!SGMaterial->HasUserChannel(USER_MATERIAL_CHANNEL_METALLIC))
				SGMaterial->AddUserChannel(USER_MATERIAL_CHANNEL_METALLIC);

			if(!SGMaterial->HasUserChannel(USER_MATERIAL_CHANNEL_ROUGHNESS))
				SGMaterial->AddUserChannel(USER_MATERIAL_CHANNEL_ROUGHNESS);

			if(!SGMaterial->HasUserChannel(USER_MATERIAL_CHANNEL_SPECULAR))
				SGMaterial->AddUserChannel(USER_MATERIAL_CHANNEL_SPECULAR);

					
			SGMaterial->SetName(TCHAR_TO_ANSI(*FString::Printf(TEXT("Material%d"), MaterialIndex)));
			
			// BaseColor
			if (FlattenMaterial.DiffuseSamples.Num())
			{
				SetMaterialChannelData(FlattenMaterial.DiffuseSamples, FlattenMaterial.DiffuseSize, SGMaterial, SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE);
			}

			// Normal
			if (FlattenMaterial.NormalSamples.Num())
			{
				OutCastProperties.bCastNormals = true;
				SetMaterialChannelData(FlattenMaterial.NormalSamples, FlattenMaterial.NormalSize, SGMaterial, SimplygonSDK::SG_MATERIAL_CHANNEL_NORMALS);
			}

			// Metallic
			if (FlattenMaterial.MetallicSamples.Num())
			{
				OutCastProperties.bCastMetallic = true;
				SetMaterialChannelData(FlattenMaterial.MetallicSamples, FlattenMaterial.MetallicSize, SGMaterial, USER_MATERIAL_CHANNEL_METALLIC);
			}

			// Roughness
			if (FlattenMaterial.RoughnessSamples.Num())
			{
				OutCastProperties.bCastRoughness = true;
				SetMaterialChannelData(FlattenMaterial.RoughnessSamples, FlattenMaterial.RoughnessSize, SGMaterial, USER_MATERIAL_CHANNEL_ROUGHNESS);
			}

			// Specular
			if (FlattenMaterial.SpecularSamples.Num())
			{
				OutCastProperties.bCastSpecular = true;
				SetMaterialChannelData(FlattenMaterial.SpecularSamples, FlattenMaterial.SpecularSize, SGMaterial, USER_MATERIAL_CHANNEL_SPECULAR);
			}
			
 			OutSGMaterialTable->AddMaterial(SGMaterial);
		}

		return true;
	}

	void GetMaterialChannelData(const SimplygonSDK::spMaterial& InSGMaterial, const char* SGMaterialChannelName, TArray<FColor>& OutSamples, FIntPoint& OutTextureSize)
	{
		SimplygonSDK::spImageData SGChannelData = InSGMaterial->GetLayeredTextureImage(SGMaterialChannelName, 0);
		if (SGChannelData)
		{
			SimplygonSDK::spUnsignedCharArray ImageColors = SimplygonSDK::SafeCast<SimplygonSDK::IUnsignedCharArray>(SGChannelData->GetColors());
			
			OutTextureSize.X = SGChannelData->GetXSize();
			OutTextureSize.Y = SGChannelData->GetYSize();
			
			int32 TexelsCount = OutTextureSize.X*OutTextureSize.Y;
			OutSamples.Empty(TexelsCount);
			OutSamples.AddUninitialized(TexelsCount);

			for (int32 TexelIndex = 0; TexelIndex < TexelsCount; ++TexelIndex)
			{
				uint8 ColorData[4];
				ImageColors->GetTuple(TexelIndex, (unsigned char*)&ColorData);
			
				OutSamples[TexelIndex].R = ColorData[0];
				OutSamples[TexelIndex].G = ColorData[1];
				OutSamples[TexelIndex].B = ColorData[2];
				OutSamples[TexelIndex].A = (SGMaterialChannelName == SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE ? ColorData[3] : FColor::White.A);
			}
		}
	}

	void CreateFlattenMaterialFromSGMaterial(
		SimplygonSDK::spMaterialTable& InSGMaterialTable, 
		MaterialExportUtils::FFlattenMaterial& OutMaterial)
	{
		SimplygonSDK::spMaterial SGMaterial = InSGMaterialTable->GetMaterial(0);
		
		// Diffuse
		GetMaterialChannelData(SGMaterial, SimplygonSDK::SG_MATERIAL_CHANNEL_DIFFUSE, OutMaterial.DiffuseSamples, OutMaterial.DiffuseSize);

		// Normal
		GetMaterialChannelData(SGMaterial, SimplygonSDK::SG_MATERIAL_CHANNEL_NORMALS, OutMaterial.NormalSamples, OutMaterial.NormalSize);
	
		// Metallic
		GetMaterialChannelData(SGMaterial, USER_MATERIAL_CHANNEL_METALLIC, OutMaterial.MetallicSamples, OutMaterial.MetallicSize);

		// Roughness
		GetMaterialChannelData(SGMaterial, USER_MATERIAL_CHANNEL_ROUGHNESS, OutMaterial.RoughnessSamples, OutMaterial.RoughnessSize);

		// Specular
		GetMaterialChannelData(SGMaterial, USER_MATERIAL_CHANNEL_SPECULAR, OutMaterial.SpecularSamples, OutMaterial.SpecularSize);
	}
};

TScopedPointer<FSimplygonMeshReduction> GSimplygonMeshReduction;

void FSimplygonMeshReductionModule::StartupModule()
{
	GSimplygonMeshReduction = FSimplygonMeshReduction::Create();
}

void FSimplygonMeshReductionModule::ShutdownModule()
{
	GSimplygonMeshReduction = NULL;
}

IMeshReduction* FSimplygonMeshReductionModule::GetMeshReductionInterface()
{
	return GSimplygonMeshReduction;
}

IMeshMerging* FSimplygonMeshReductionModule::GetMeshMergingInterface()
{
	return GSimplygonMeshReduction;
}

#undef LOCTEXT_NAMESPACE