FbxTimeSpan UnFbx::FFbxImporter::GetAnimationTimeSpan(FbxNode* RootNode, FbxAnimStack* AnimStack)
{
	FBXImportOptions* ImportOption = GetImportOptions();
	FbxTimeSpan AnimTimeSpan(FBXSDK_TIME_INFINITE, FBXSDK_TIME_MINUS_INFINITE);
	if (ImportOption)
	{
		if (ImportOption->AnimationLengthImportType == FBXALIT_AnimatedKey)
		{
			RootNode->GetAnimationInterval(AnimTimeSpan, AnimStack);
		}
		else if  (ImportOption->AnimationLengthImportType == FBXALIT_ExportedTime)
		{
			AnimTimeSpan = AnimStack->GetLocalTimeSpan();
		}
		else // then it's range 
		{
			AnimTimeSpan = AnimStack->GetLocalTimeSpan();

			FbxTimeSpan AnimatedInterval(FBXSDK_TIME_INFINITE, FBXSDK_TIME_MINUS_INFINITE);
			RootNode->GetAnimationInterval(AnimatedInterval, AnimStack);

			// find the most range that covers by both method, that'll be used for clamping
			FbxTime StartTime = FMath::Min<FbxTime>(AnimTimeSpan.GetStart(), AnimatedInterval.GetStart());
			FbxTime StopTime = FMath::Max<FbxTime>(AnimTimeSpan.GetStop(),AnimatedInterval.GetStop());

			// make inclusive time between localtimespan and animation interval
			AnimTimeSpan.SetStart(StartTime);
			AnimTimeSpan.SetStop(StopTime);

			// hopefully this is going to be whole frames
			// our game has DEFAULT_SAMPLERATE frames per second. 
			FbxTime EachFrame = FBXSDK_TIME_ONE_SECOND/DEFAULT_SAMPLERATE;
			int32 StartFrame = StartTime.Get()/EachFrame.Get();
			int32 StopFrame = StopTime.Get()/EachFrame.Get();
			if (StartFrame != StopFrame)
			{
				FbxTime Duration = AnimTimeSpan.GetDuration();

				ImportOption->AnimationRange.X = FMath::Clamp<int32>(ImportOption->AnimationRange.X, StartFrame, StopFrame);
				ImportOption->AnimationRange.Y = FMath::Clamp<int32>(ImportOption->AnimationRange.Y, StartFrame, StopFrame);

				FbxLongLong Interval = EachFrame.Get();

				// now set new time
				if (StartFrame != ImportOption->AnimationRange.X)
				{
					FbxTime NewTime(ImportOption->AnimationRange.X*Interval);
					AnimTimeSpan.SetStart(NewTime);
				}

				if (StopFrame != ImportOption->AnimationRange.Y)
				{
					FbxTime NewTime(ImportOption->AnimationRange.Y*Interval);
					AnimTimeSpan.SetStop(NewTime);
				}
			}
		}
	}

	return AnimTimeSpan;
}
bool UnFbx::FFbxImporter::ValidateAnimStack(TArray<FbxNode*>& SortedLinks, TArray<FbxNode*>& NodeArray, FbxAnimStack* CurAnimStack, int32 ResampleRate, bool bImportMorph, FbxTimeSpan &AnimTimeSpan)
{
	// set current anim stack
	Scene->SetCurrentAnimationStack(CurAnimStack);

	UE_LOG(LogFbx, Log, TEXT("Parsing AnimStack %s"),UTF8_TO_TCHAR(CurAnimStack->GetName()));

	// There are a FBX unroll filter bug, so don't bake animation layer at all
	MergeAllLayerAnimation(CurAnimStack, ResampleRate);

	bool bValidAnimStack = true;

	AnimTimeSpan = GetAnimationTimeSpan(SortedLinks[0], CurAnimStack);
	
	// if no duration is found, return false
	if (AnimTimeSpan.GetDuration() <= 0)
	{
		return false;
	}

	const FBXImportOptions* ImportOption = GetImportOptions();
	// only add morph time if not setrange. If Set Range there is no reason to override time
	if ( bImportMorph && ImportOption->AnimationLengthImportType != FBXALIT_SetRange)
	{
		for ( int32 NodeIndex = 0; NodeIndex < NodeArray.Num(); NodeIndex++ )
		{
			// consider blendshape animation curve
			FbxGeometry* Geometry = (FbxGeometry*)NodeArray[NodeIndex]->GetNodeAttribute();
			if (Geometry)
			{
				int32 BlendShapeDeformerCount = Geometry->GetDeformerCount(FbxDeformer::eBlendShape);
				for(int32 BlendShapeIndex = 0; BlendShapeIndex<BlendShapeDeformerCount; ++BlendShapeIndex)
				{
					FbxBlendShape* BlendShape = (FbxBlendShape*)Geometry->GetDeformer(BlendShapeIndex, FbxDeformer::eBlendShape);

					int32 BlendShapeChannelCount = BlendShape->GetBlendShapeChannelCount();
					for(int32 ChannelIndex = 0; ChannelIndex<BlendShapeChannelCount; ++ChannelIndex)
					{
						FbxBlendShapeChannel* Channel = BlendShape->GetBlendShapeChannel(ChannelIndex);

						if(Channel)
						{
							// Get the percentage of influence of the shape.
							FbxAnimCurve* Curve = Geometry->GetShapeChannel(BlendShapeIndex, ChannelIndex, (FbxAnimLayer*)CurAnimStack->GetMember(0));
							if (Curve && Curve->KeyGetCount() > 0)
							{
								FbxTimeSpan TmpAnimSpan;

								if (Curve->GetTimeInterval(TmpAnimSpan))
								{
									bValidAnimStack = true;
									// update animation interval to include morph target range
									AnimTimeSpan.UnionAssignment(TmpAnimSpan);
								}
							}
						}
					}
				}
			}
		}
	}

	return bValidAnimStack;
}
UObject* UFbxFactory::FactoryCreateBinary
(
 UClass*			Class,
 UObject*			InParent,
 FName				Name,
 EObjectFlags		Flags,
 UObject*			Context,
 const TCHAR*		Type,
 const uint8*&		Buffer,
 const uint8*		BufferEnd,
 FFeedbackContext*	Warn,
 bool&				bOutOperationCanceled
 )
{
	if( bOperationCanceled )
	{
		bOutOperationCanceled = true;
		FEditorDelegates::OnAssetPostImport.Broadcast(this, NULL);
		return NULL;
	}

	FEditorDelegates::OnAssetPreImport.Broadcast(this, Class, InParent, Name, Type);

	UObject* NewObject = NULL;

	if ( bDetectImportTypeOnImport )
	{
		if ( !DetectImportType(UFactory::CurrentFilename) )
		{
			// Failed to read the file info, fail the import
			FEditorDelegates::OnAssetPostImport.Broadcast(this, NULL);
			return NULL;
		}
	}
	// logger for all error/warnings
	// this one prints all messages that are stored in FFbxImporter
	UnFbx::FFbxImporter* FbxImporter = UnFbx::FFbxImporter::GetInstance();
	
	UnFbx::FFbxLoggerSetter Logger(FbxImporter);

	EFBXImportType ForcedImportType = FBXIT_StaticMesh;

	bool bIsObjFormat = false;
	if( FString(Type).Equals(TEXT("obj"), ESearchCase::IgnoreCase ) )
	{
		bIsObjFormat = true;
	}


	bool bShowImportDialog = bShowOption && !GIsAutomationTesting;
	bool bImportAll = false;
	UnFbx::FBXImportOptions* ImportOptions = GetImportOptions(FbxImporter, ImportUI, bShowImportDialog, InParent->GetPathName(), bOperationCanceled, bImportAll, bIsObjFormat, bIsObjFormat, ForcedImportType );
	bOutOperationCanceled = bOperationCanceled;
	
	if( bImportAll )
	{
		// If the user chose to import all, we don't show the dialog again and use the same settings for each object until importing another set of files
		bShowOption = false;
	}

	// For multiple files, use the same settings
	bDetectImportTypeOnImport = false;

	if (ImportOptions)
	{
		Warn->BeginSlowTask( NSLOCTEXT("FbxFactory", "BeginImportingFbxMeshTask", "Importing FBX mesh"), true );
		if ( !FbxImporter->ImportFromFile( *UFactory::CurrentFilename, Type ) )
		{
			// Log the error message and fail the import.
			Warn->Log(ELogVerbosity::Error, FbxImporter->GetErrorMessage() );
		}
		else
		{
			// Log the import message and import the mesh.
			const TCHAR* errorMessage = FbxImporter->GetErrorMessage();
			if (errorMessage[0] != '\0')
			{
				Warn->Log( errorMessage );
			}

			FbxNode* RootNodeToImport = NULL;
			RootNodeToImport = FbxImporter->Scene->GetRootNode();

			// For animation and static mesh we assume there is at lease one interesting node by default
			int32 InterestingNodeCount = 1;
			TArray< TArray<FbxNode*>* > SkelMeshArray;

			bool bImportStaticMeshLODs = ImportUI->StaticMeshImportData->bImportMeshLODs;
			bool bCombineMeshes = ImportUI->bCombineMeshes;

			if ( ImportUI->MeshTypeToImport == FBXIT_SkeletalMesh )
			{
				FbxImporter->FillFbxSkelMeshArrayInScene(RootNodeToImport, SkelMeshArray, false);
				InterestingNodeCount = SkelMeshArray.Num();
			}
			else if( ImportUI->MeshTypeToImport == FBXIT_StaticMesh )
			{
				FbxImporter->ApplyTransformSettingsToFbxNode(RootNodeToImport, ImportUI->StaticMeshImportData);

				if( bCombineMeshes && !bImportStaticMeshLODs )
				{
					// If Combine meshes and dont import mesh LODs, the interesting node count should be 1 so all the meshes are grouped together into one static mesh
					InterestingNodeCount = 1;
				}
				else
				{
					// count meshes in lod groups if we dont care about importing LODs
					bool bCountLODGroupMeshes = !bImportStaticMeshLODs;
					int32 NumLODGroups = 0;
					InterestingNodeCount = FbxImporter->GetFbxMeshCount(RootNodeToImport,bCountLODGroupMeshes,NumLODGroups);

					// if there were LODs in the file, do not combine meshes even if requested
					if( bImportStaticMeshLODs && bCombineMeshes )
					{
						bCombineMeshes = NumLODGroups == 0;
					}
				}
			}

		
			if (InterestingNodeCount > 1)
			{
				// the option only works when there are only one asset
				ImportOptions->bUsedAsFullName = false;
			}

			const FString Filename( UFactory::CurrentFilename );
			if (RootNodeToImport && InterestingNodeCount > 0)
			{  
				int32 NodeIndex = 0;

				int32 ImportedMeshCount = 0;
				UStaticMesh* NewStaticMesh = NULL;
				if ( ImportUI->MeshTypeToImport == FBXIT_StaticMesh )  // static mesh
				{
					if (bCombineMeshes)
					{
						TArray<FbxNode*> FbxMeshArray;
						FbxImporter->FillFbxMeshArray(RootNodeToImport, FbxMeshArray, FbxImporter);
						if (FbxMeshArray.Num() > 0)
						{
							NewStaticMesh = FbxImporter->ImportStaticMeshAsSingle(InParent, FbxMeshArray, Name, Flags, ImportUI->StaticMeshImportData, NULL, 0);
						}

						ImportedMeshCount = NewStaticMesh ? 1 : 0;
					}
					else
					{
						TArray<UObject*> AllNewAssets;
						UObject* Object = RecursiveImportNode(FbxImporter,RootNodeToImport,InParent,Name,Flags,NodeIndex,InterestingNodeCount, AllNewAssets);

						NewStaticMesh = Cast<UStaticMesh>( Object );

						// Make sure to notify the asset registry of all assets created other than the one returned, which will notify the asset registry automatically.
						for ( auto AssetIt = AllNewAssets.CreateConstIterator(); AssetIt; ++AssetIt )
						{
							UObject* Asset = *AssetIt;
							if ( Asset != NewStaticMesh )
							{
								FAssetRegistryModule::AssetCreated(Asset);
								Asset->MarkPackageDirty();
							}
						}

						ImportedMeshCount = AllNewAssets.Num();
					}

					// Importing static mesh sockets only works if one mesh is being imported
					if( ImportedMeshCount == 1 && NewStaticMesh )
					{
						FbxImporter->ImportStaticMeshSockets( NewStaticMesh );
					}

					NewObject = NewStaticMesh;

				}
				else if ( ImportUI->MeshTypeToImport == FBXIT_SkeletalMesh )// skeletal mesh
				{
					int32 TotalNumNodes = 0;

					for (int32 i = 0; i < SkelMeshArray.Num(); i++)
					{
						TArray<FbxNode*> NodeArray = *SkelMeshArray[i];
					
						TotalNumNodes += NodeArray.Num();
						// check if there is LODGroup for this skeletal mesh
						int32 MaxLODLevel = 1;
						for (int32 j = 0; j < NodeArray.Num(); j++)
						{
							FbxNode* Node = NodeArray[j];
							if (Node->GetNodeAttribute() && Node->GetNodeAttribute()->GetAttributeType() == FbxNodeAttribute::eLODGroup)
							{
								// get max LODgroup level
								if (MaxLODLevel < Node->GetChildCount())
								{
									MaxLODLevel = Node->GetChildCount();
								}
							}
						}
					
						int32 LODIndex;
						bool bImportSkeletalMeshLODs = ImportUI->SkeletalMeshImportData->bImportMeshLODs;
						for (LODIndex = 0; LODIndex < MaxLODLevel; LODIndex++)
						{
							if ( !bImportSkeletalMeshLODs && LODIndex > 0) // not import LOD if UI option is OFF
							{
								break;
							}
						
							TArray<FbxNode*> SkelMeshNodeArray;
							for (int32 j = 0; j < NodeArray.Num(); j++)
							{
								FbxNode* Node = NodeArray[j];
								if (Node->GetNodeAttribute() && Node->GetNodeAttribute()->GetAttributeType() == FbxNodeAttribute::eLODGroup)
								{
									if (Node->GetChildCount() > LODIndex)
									{
										SkelMeshNodeArray.Add(Node->GetChild(LODIndex));
									}
									else // in less some LODGroups have less level, use the last level
									{
										SkelMeshNodeArray.Add(Node->GetChild(Node->GetChildCount() - 1));
									}
								}
								else
								{
									SkelMeshNodeArray.Add(Node);
								}
							}
						
							if (LODIndex == 0 && SkelMeshNodeArray.Num() != 0)
							{
								FName OutputName = FbxImporter->MakeNameForMesh(Name.ToString(), SkelMeshNodeArray[0]);

								USkeletalMesh* NewMesh = FbxImporter->ImportSkeletalMesh( InParent, SkelMeshNodeArray, OutputName, Flags, ImportUI->SkeletalMeshImportData, &bOperationCanceled );
								NewObject = NewMesh;

								if(bOperationCanceled)
								{
									// User cancelled, clean up and return
									FbxImporter->ReleaseScene();
									Warn->EndSlowTask();
									bOperationCanceled = true;
									return nullptr;
								}

								if ( NewMesh && ImportUI->bImportAnimations )
								{
									// We need to remove all scaling from the root node before we set up animation data.
									// Othewise some of the global transform calculations will be incorrect.
									FbxImporter->RemoveTransformSettingsFromFbxNode(RootNodeToImport, ImportUI->SkeletalMeshImportData);
									FbxImporter->SetupAnimationDataFromMesh(NewMesh, InParent, SkelMeshNodeArray, ImportUI->AnimSequenceImportData, OutputName.ToString());

									// Reapply the transforms for the rest of the import
									FbxImporter->ApplyTransformSettingsToFbxNode(RootNodeToImport, ImportUI->SkeletalMeshImportData);
								}
							}
							else if (NewObject) // the base skeletal mesh is imported successfully
							{
								USkeletalMesh* BaseSkeletalMesh = Cast<USkeletalMesh>(NewObject);
								FName LODObjectName = NAME_None;
								USkeletalMesh *LODObject = FbxImporter->ImportSkeletalMesh( GetTransientPackage(), SkelMeshNodeArray, LODObjectName, RF_NoFlags, ImportUI->SkeletalMeshImportData, &bOperationCanceled );
								bool bImportSucceeded = !bOperationCanceled && FbxImporter->ImportSkeletalMeshLOD(LODObject, BaseSkeletalMesh, LODIndex, false);

								if (bImportSucceeded)
								{
									BaseSkeletalMesh->LODInfo[LODIndex].ScreenSize = 1.0f / (MaxLODLevel * LODIndex);
								}
								else
								{
									FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_SkeletalMeshLOD", "Failed to import Skeletal mesh LOD.")), FFbxErrors::SkeletalMesh_LOD_FailedToImport);
								}
							}
						
							// import morph target
							if ( NewObject && ImportUI->SkeletalMeshImportData->bImportMorphTargets)
							{
								// Disable material importing when importing morph targets
								uint32 bImportMaterials = ImportOptions->bImportMaterials;
								ImportOptions->bImportMaterials = 0;

								FbxImporter->ImportFbxMorphTarget(SkelMeshNodeArray, Cast<USkeletalMesh>(NewObject), InParent, LODIndex);
							
								ImportOptions->bImportMaterials = !!bImportMaterials;
							}
						}
					
						if (NewObject)
						{
							NodeIndex++;
							FFormatNamedArguments Args;
							Args.Add( TEXT("NodeIndex"), NodeIndex );
							Args.Add( TEXT("ArrayLength"), SkelMeshArray.Num() );
							GWarn->StatusUpdate( NodeIndex, SkelMeshArray.Num(), FText::Format( NSLOCTEXT("UnrealEd", "Importingf", "Importing ({NodeIndex} of {ArrayLength})"), Args ) );
						}
					}
				
					for (int32 i = 0; i < SkelMeshArray.Num(); i++)
					{
						delete SkelMeshArray[i];
					}
					
					// if total nodes we found is 0, we didn't find anything. 
					if (TotalNumNodes == 0)
					{
						FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_NoMeshFoundOnRoot", "Could not find any valid mesh on the root hierarchy. If you have mesh in the sub hierarchy, please enable option of [Import Meshes In Bone Hierarchy] when import.")), 
							FFbxErrors::SkeletalMesh_NoMeshFoundOnRoot);
					}
				}
				else if ( ImportUI->MeshTypeToImport == FBXIT_Animation )// animation
				{
					if (ImportOptions->SkeletonForAnimation)
					{
						// will return the last animation sequence that were added
						NewObject = UEditorEngine::ImportFbxAnimation( ImportOptions->SkeletonForAnimation, InParent, ImportUI->AnimSequenceImportData, *Filename, *Name.ToString(), true );
					}
				}
			}
			else
			{
				if (RootNodeToImport == NULL)
				{
					FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_InvalidRoot", "Could not find root node.")), FFbxErrors::SkeletalMesh_InvalidRoot);
				}
				else if (ImportUI->MeshTypeToImport == FBXIT_SkeletalMesh)
				{
					FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_InvalidBone", "Failed to find any bone hierarchy. Try disabling the \"Import As Skeletal\" option to import as a rigid mesh. ")), FFbxErrors::SkeletalMesh_InvalidBone);
				}
				else
				{
					FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_InvalidNode", "Could not find any node.")), FFbxErrors::SkeletalMesh_InvalidNode);
				}
			}
		}

		if (NewObject == NULL)
		{
			FbxImporter->AddTokenizedErrorMessage(FTokenizedMessage::Create(EMessageSeverity::Error, LOCTEXT("FailedToImport_NoObject", "Import failed.")), FFbxErrors::Generic_ImportingNewObjectFailed);
		}

		FbxImporter->ReleaseScene();
		Warn->EndSlowTask();
	}

	FEditorDelegates::OnAssetPostImport.Broadcast(this, NewObject);

	return NewObject;
}