text: // Copyright 1998-2016 Epic Games, Inc. All Rights Reserved.
  
  #include "AnimGraphRuntimePrivatePCH.h"
  #include "AnimNodes/AnimNode_RotateRootBone.h"
  
  /////////////////////////////////////////////////////
  // FAnimNode_RotateRootBone
  
  void FAnimNode_RotateRootBone::Initialize(const FAnimationInitializeContext& Context)
  {
  	FAnimNode_Base::Initialize(Context);
  
  	BasePose.Initialize(Context);
  }
  
  void FAnimNode_RotateRootBone::CacheBones(const FAnimationCacheBonesContext& Context) 
  {
  	BasePose.CacheBones(Context);
  }
  
  void FAnimNode_RotateRootBone::Update(const FAnimationUpdateContext& Context)
  {
  	EvaluateGraphExposedInputs.Execute(Context);
  	BasePose.Update(Context);
  }
  
  void FAnimNode_RotateRootBone::Evaluate(FPoseContext& Output)
  {
  	// Evaluate the input
  	BasePose.Evaluate(Output);
  
  	checkSlow(!FMath::IsNaN(Yaw) && FMath::IsFinite(Yaw));
  	checkSlow(!FMath::IsNaN(Pitch) && FMath::IsFinite(Pitch));
  
  	if (!FMath::IsNearlyZero(Pitch, KINDA_SMALL_NUMBER) || !FMath::IsNearlyZero(Yaw, KINDA_SMALL_NUMBER))
  	{
  		// Build our desired rotation
  		const FRotator DeltaRotation(Pitch, Yaw, 0.f);
  		const FQuat DeltaQuat(DeltaRotation);
  		const FQuat MeshToComponentQuat(MeshToComponent);
  
  		// Convert our rotation from Component Space to Mesh Space.
  		const FQuat MeshSpaceDeltaQuat = MeshToComponentQuat.Inverse() * DeltaQuat * MeshToComponentQuat;
  
  		// Apply rotation to root bone.
  		FCompactPoseBoneIndex RootBoneIndex(0);
  		Output.Pose[RootBoneIndex].SetRotation(Output.Pose[RootBoneIndex].GetRotation() * MeshSpaceDeltaQuat);
  		Output.Pose[RootBoneIndex].NormalizeRotation();
  	}
  }
  
  
  void FAnimNode_RotateRootBone::GatherDebugData(FNodeDebugData& DebugData)
  {
  	FString DebugLine = DebugData.GetNodeName(this);
  	
  	DebugLine += FString::Printf(TEXT("(Pitch: %.2f Yaw: %.2f)"), Pitch, Yaw);
  	DebugData.AddDebugItem(DebugLine);
  
  	BasePose.GatherDebugData(DebugData);
  }
  
  FAnimNode_RotateRootBone::FAnimNode_RotateRootBone()
  	: Pitch(0.0f)
  	, Yaw(0.0f)
  	, MeshToComponent(FRotator::ZeroRotator)
  {
  }
  