bool UAnimExporterITP::ExportText(const FExportObjectInnerContext* Context, UObject* Object, const TCHAR* Type, FOutputDevice& Ar, FFeedbackContext* Warn, uint32 PortFlags /*= 0*/)
{
	UAnimSequence* AnimSeq = CastChecked<UAnimSequence>(Object);

	USkeleton* Skeleton = AnimSeq->GetSkeleton();
	const FReferenceSkeleton& RefSkeleton = Skeleton->GetReferenceSkeleton();
	USkeletalMesh* SkelMesh = Skeleton->GetPreviewMesh();
	if (AnimSeq->SequenceLength == 0.f)
	{
		// something is wrong
		return false;
	}

	const float FrameRate = AnimSeq->NumFrames / AnimSeq->SequenceLength;

	// Open another archive
	FArchive* File = IFileManager::Get().CreateFileWriter(*UExporter::CurrentFilename);

	// Let's try the header...
	File->Logf(TEXT("{"));
	File->Logf(TEXT("\t\"metadata\":{"));
	File->Logf(TEXT("\t\t\"type\":\"itpanim\","));
	File->Logf(TEXT("\t\t\"version\":2"));
	File->Logf(TEXT("\t},"));

	File->Logf(TEXT("\t\"sequence\":{"));
	File->Logf(TEXT("\t\t\"frames\":%d,"), AnimSeq->NumFrames);
	File->Logf(TEXT("\t\t\"length\":%f,"), AnimSeq->SequenceLength);
	File->Logf(TEXT("\t\t\"bonecount\":%d,"), RefSkeleton.GetNum());
	File->Logf(TEXT("\t\t\"tracks\":["));

	bool firstOutput = false;

	for (int32 BoneIndex = 0; BoneIndex < RefSkeleton.GetNum(); ++BoneIndex)
	{
		//int32 BoneTreeIndex = Skeleton->GetSkeletonBoneIndexFromMeshBoneIndex(SkelMesh, BoneIndex);
		int32 BoneTrackIndex = Skeleton->GetAnimationTrackIndex(BoneIndex, AnimSeq);
		
		if (BoneTrackIndex == INDEX_NONE)
		{
			// If this sequence does not have a track for the current bone, then skip it
			continue;
		}
	
		if (firstOutput)
		{
			File->Logf(TEXT("\t\t\t},"));
		}

		firstOutput = true;

		File->Logf(TEXT("\t\t\t{"));
		File->Logf(TEXT("\t\t\t\t\"bone\":%d,"), BoneIndex);
		File->Logf(TEXT("\t\t\t\t\"transforms\":["));
		float AnimTime = 0.0f;
		float AnimEndTime = AnimSeq->SequenceLength;
		// Subtracts 1 because NumFrames includes an initial pose for 0.0 second
		double TimePerKey = (AnimSeq->SequenceLength / (AnimSeq->NumFrames - 1));
		const float AnimTimeIncrement = TimePerKey;

		bool bLastKey = false;
		// Step through each frame and add the bone's transformation data
		while (!bLastKey)
		{
			const TArray<FBoneNode>& BoneTree = Skeleton->GetBoneTree();

			FTransform BoneAtom;
			AnimSeq->GetBoneTransform(BoneAtom, BoneTrackIndex, AnimTime, true);

			bLastKey = AnimTime >= AnimEndTime;

			File->Logf(TEXT("\t\t\t\t\t{"));

			FQuat rot = BoneAtom.GetRotation();
			// For the root bone, we need to fix-up the rotation because Unreal exports
			// animations with Y-forward for some reason (maybe because Maya?)
			if (BoneIndex == 0)
			{
				FQuat addRot(FVector(0.0f, 0.0f, 1.0f), -1.57f);
				rot = addRot * rot;
			}
			File->Logf(TEXT("\t\t\t\t\t\t\"rot\":[%f,%f,%f,%f],"), rot.X, rot.Y, rot.Z, rot.W);
			FVector trans = BoneAtom.GetTranslation();

			// Sanjay: If it's skeleton retargeting, change the translation to be from the ref pose skeleton
			if (BoneTree[BoneIndex].TranslationRetargetingMode == EBoneTranslationRetargetingMode::Skeleton)
			{
				const FTransform& BoneTransform = RefSkeleton.GetRefBonePose()[BoneIndex];
				trans = BoneTransform.GetTranslation();
			}

			File->Logf(TEXT("\t\t\t\t\t\t\"trans\":[%f,%f,%f]"), trans.X, trans.Y, trans.Z);

			if (!bLastKey)
			{
				File->Logf(TEXT("\t\t\t\t\t},"));
			}
			else
			{
				File->Logf(TEXT("\t\t\t\t\t}"));
			}
			

			AnimTime += AnimTimeIncrement;
		}

		File->Logf(TEXT("\t\t\t\t]"), BoneIndex);
	}

	File->Logf(TEXT("\t\t\t}"));
	File->Logf(TEXT("\t\t]"));
	File->Logf(TEXT("\t}"));

 	File->Logf(TEXT("}"));
 	delete File;

	return true;
}
void FFbxExporter::ExportAnimSequenceToFbx(const UAnimSequence* AnimSeq,
									 const USkeletalMesh* SkelMesh,
									 TArray<FbxNode*>& BoneNodes,
									 FbxAnimLayer* InAnimLayer,
									 float AnimStartOffset,
									 float AnimEndOffset,
									 float AnimPlayRate,
									 float StartTime)
{
	USkeleton* Skeleton = AnimSeq->GetSkeleton();

	if (AnimSeq->SequenceLength == 0.f)
	{
		// something is wrong
		return;	
	}

	const float FrameRate			=  AnimSeq->NumFrames / AnimSeq->SequenceLength;

	// set time correctly
	FbxTime ExportedStartTime, ExportedStopTime;
	if ( FMath::IsNearlyEqual(FrameRate, DEFAULT_SAMPLERATE, 1.f) )
	{
		ExportedStartTime.SetGlobalTimeMode(FbxTime::eFrames30);
		ExportedStopTime.SetGlobalTimeMode(FbxTime::eFrames30);
	}
	else
	{
		ExportedStartTime.SetGlobalTimeMode(FbxTime::eCustom, FrameRate);
		ExportedStopTime.SetGlobalTimeMode(FbxTime::eCustom, FrameRate);
	}

	ExportedStartTime.SetSecondDouble(0.f);
	ExportedStopTime.SetSecondDouble(AnimSeq->SequenceLength);

	FbxTimeSpan ExportedTimeSpan;
	ExportedTimeSpan.Set(ExportedStartTime, ExportedStopTime);
	AnimStack->SetLocalTimeSpan(ExportedTimeSpan);
	
	// Add the animation data to the bone nodes
	for(int32 BoneIndex = 0; BoneIndex < BoneNodes.Num(); ++BoneIndex)
	{
		FbxNode* CurrentBoneNode = BoneNodes[BoneIndex];

		// Create the AnimCurves
		FbxAnimCurve* Curves[6];
		Curves[0] = CurrentBoneNode->LclTranslation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_X, true);
		Curves[1] = CurrentBoneNode->LclTranslation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_Y, true);
		Curves[2] = CurrentBoneNode->LclTranslation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_Z, true);

		Curves[3] = CurrentBoneNode->LclRotation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_X, true);
		Curves[4] = CurrentBoneNode->LclRotation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_Y, true);
		Curves[5] = CurrentBoneNode->LclRotation.GetCurve(InAnimLayer, FBXSDK_CURVENODE_COMPONENT_Z, true);

		float AnimTime					= AnimStartOffset;
		float AnimEndTime				= (AnimSeq->SequenceLength - AnimEndOffset);
		// Subtracts 1 because NumFrames includes an initial pose for 0.0 second
		double TimePerKey				= (AnimSeq->SequenceLength / (AnimSeq->NumFrames-1));
		const float AnimTimeIncrement	= TimePerKey * AnimPlayRate;

		FbxTime ExportTime;
		ExportTime.SetSecondDouble(StartTime);

		FbxTime ExportTimeIncrement;
		ExportTimeIncrement.SetSecondDouble( TimePerKey );

		int32 BoneTreeIndex = Skeleton->GetSkeletonBoneIndexFromMeshBoneIndex(SkelMesh, BoneIndex);
		int32 BoneTrackIndex = Skeleton->GetAnimationTrackIndex(BoneTreeIndex, AnimSeq);
		if(BoneTrackIndex == INDEX_NONE)
		{
			// If this sequence does not have a track for the current bone, then skip it
			continue;
		}

		for(int32 i = 0; i < 6; ++i)
		{
			Curves[i]->KeyModifyBegin();
		}

		bool bLastKey = false;
		// Step through each frame and add the bone's transformation data
		while (!bLastKey)
		{
			FTransform BoneAtom;
			AnimSeq->GetBoneTransform(BoneAtom, BoneTrackIndex, AnimTime, true);

			FbxVector4 Translation = Converter.ConvertToFbxPos(BoneAtom.GetTranslation());

			FbxVector4 Rotation = Converter.ConvertToFbxRot(BoneAtom.GetRotation().Euler());
		
			int32 lKeyIndex;

			bLastKey = AnimTime >= AnimEndTime;
			for(int32 i = 0, j=3; i < 3; ++i, ++j)
			{
				lKeyIndex = Curves[i]->KeyAdd(ExportTime);
				Curves[i]->KeySetValue(lKeyIndex, Translation[i]);
				Curves[i]->KeySetInterpolation(lKeyIndex, bLastKey ? FbxAnimCurveDef::eInterpolationConstant : FbxAnimCurveDef::eInterpolationCubic);

				if( bLastKey )
				{
					Curves[i]->KeySetConstantMode( lKeyIndex, FbxAnimCurveDef::eConstantStandard );
				}

				lKeyIndex = Curves[j]->KeyAdd(ExportTime);
				Curves[j]->KeySetValue(lKeyIndex, Rotation[i]);
				Curves[j]->KeySetInterpolation(lKeyIndex, bLastKey ? FbxAnimCurveDef::eInterpolationConstant : FbxAnimCurveDef::eInterpolationCubic);

				if( bLastKey )
				{
					Curves[j]->KeySetConstantMode( lKeyIndex, FbxAnimCurveDef::eConstantStandard );
				}
			}

			ExportTime += ExportTimeIncrement;
			AnimTime += AnimTimeIncrement;
		}

		for(int32 i = 0; i < 6; ++i)
		{
			Curves[i]->KeyModifyEnd();
		}
	}
}