目的:根据曲线值获得当前动作帧。用于实现各种通过曲线同步的功能。
方法:继承FAnimNode_Base创建自定义动画节点。重写Evaluate部分。创建相应的AnimGraphNode。可参考前一篇http://blog.csdn.net/u010831746/article/details/50733287
Evaluate : 1. 根据曲线Value(Y轴)值获得Time(X轴)值。
曲线KeyArray所在位置。AnimSequenceBase : RawCurveData.
类型AnimCurveTypes.h:FRawCurveTracks
曲线记录是TArray<FRichCurveKey>。每个key中存有Time和Value。根据输入的CurveValue,遍历Array查找Value最接近的Key,返回Time。
2.根据Time值获得动画POS
AnimSequence->GetAnimationPose(…, Time, …)输出Pose。
主要代码:
AnimNode_EvaluatePose.h
/*!
* \file AnimNode_EvaluatePose.h
* \date 2016/03/29 17:45
*
* \author: Jia Zhipeng
* Contact: jiazhipeng@pwrd.com
*
* \brief: 根据曲线获得当前Pose. Get Pose based on curve value.
*
* \note:
*/
#pragma once
#include "Animation/AnimNodeBase.h"
//#include "AnimNode_SkeletalControlBase.h"
#include "AnimNode_EvaluatePose.generated.h" USTRUCT()
struct FAnimNode_EvaluatePose :public FAnimNode_Base
{
GENERATED_USTRUCT_BODY() UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (PinShownByDefault))
UAnimSequenceBase* Sequence; UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (PinShownByDefault))
FName CurveName; UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (PinShownByDefault))
float CurveValue; UAnimInstance* MyInstance;
public:
// Constructor
FAnimNode_EvaluatePose(); // FAnimNode_Base interface
virtual void Initialize(const FAnimationInitializeContext& Context) override;
virtual void CacheBones(const FAnimationCacheBonesContext& Context) override;
virtual void Evaluate(FPoseContext& Output) override;
virtual void OverrideAsset(UAnimationAsset* NewAsset) override;
virtual void GatherDebugData(FNodeDebugData& DebugData) override;
// End of FAnimNode_Base interface// };
AnimNode_EvaluatePose.cpp
//Iterate Animation's curve's keys to get current time
void FAnimNode_EvaluatePose::Evaluate(FPoseContext& Output)
{
//CurveValue is connected to AnimInstance’s variable in AnimBlueprint, but it is not updated when executing this node. So how to get variable of AnimInstance? 2 ways.
//1. EvaluateGraphExposedInputs.Execute(Output); Cause crash. Explore this method in the future.
//2. Get property from AnimInstance. But in this way, the variable’s name has to be specified. Temporarily use this method.
UFloatProperty* FloatProp = Cast<UFloatProperty>(PW_PropertyTools::FindProperty(MyInstance, TEXT("Horiz Movement Speed")));
if (!FloatProp)
{
UE_LOG(LogTemp, Warning, TEXT("Horiz Movement Speed Not found"));
return;
}
float HorzSpeed = FloatProp->GetPropertyValue_InContainer(MyInstance);
CurveValue = HorzSpeed; USkeleton* Skeleton = Sequence->GetSkeleton();
if (!Skeleton)
{
UE_LOG(LogTemp, Warning, TEXT("FAnimNode_EvaluatePose::Evaluate fail to find skeleton"));
return;
}
FSmartNameMapping* NameMapping = Skeleton->SmartNames.GetContainer(USkeleton::AnimCurveMappingName);
// retrieve curve
USkeleton::AnimCurveUID Uid;
if (!NameMapping->Exists(CurveName))
{
UE_LOG(LogTemp, Warning, TEXT("FAnimNode_EvaluatePose::Evaluate fail to find curve %s"), *CurveName.ToString());
return;
} Uid = *NameMapping->FindUID(CurveName);
FFloatCurve * CurveToCompute = static_cast<FFloatCurve*>(Sequence->RawCurveData.GetCurveData(Uid));
if (!CurveToCompute)
{
UE_LOG(LogTemp, Warning, TEXT("FAnimNode_EvaluatePose::Evaluate fail to find curve %s"), *CurveName.ToString());
return;
} auto FloatCurve = CurveToCompute->FloatCurve;
float OutTime = 0.0f;
BinarySeach(FloatCurve, CurveValue, OutTime);
if ((Sequence != NULL) && (Output.AnimInstance->CurrentSkeleton->IsCompatible(Sequence->GetSkeleton())))
{
Sequence->GetAnimationPose(Output.Pose, Output.Curve, FAnimExtractContext(OutTime, Output.AnimInstance->ShouldExtractRootMotion()));
}
else
{
Output.ResetToRefPose();
}
}