AnimNode_LegIK.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "BoneIndices.h"
#include "BoneContainer.h"
#include "BonePose.h"
#include "BoneControllers/AnimNode_SkeletalControlBase.h"
#include "AnimNode_LegIK.generated.h"
 
class USkeletalMeshComponent;
struct FAnimLegIKData;
 
USTRUCT()
struct FIKChainLink
{
    GENERATED_USTRUCT_BODY()
 
public:
    FVector Location;
    double Length;
    FVector LinkAxisZ;
    FVector RealBendDir;
    FVector BaseBendDir;
    FName BoneName;
 
    FIKChainLink()
        : Location(FVector::ZeroVector)
        , Length(0.0)
        , LinkAxisZ(FVector::ZeroVector)
        , RealBendDir(FVector::ZeroVector)
        , BaseBendDir(FVector::ZeroVector)
        , BoneName(NAME_None)
    {}
 
    FIKChainLink(FVector InLocation, double InLength)
        : Location(InLocation)
        , Length(InLength)
        , LinkAxisZ(FVector::ZeroVector)
        , RealBendDir(FVector::ZeroVector)
        , BaseBendDir(FVector::ZeroVector)
        , BoneName(NAME_None)
    {}
};
 
USTRUCT()
struct FIKChain
{
    GENERATED_USTRUCT_BODY()
 
public:
    TArray<FIKChainLink> Links;
    float MinRotationAngleRadians;
 
private:
    FAnimInstanceProxy* MyAnimInstanceProxy;
    double TotalChainLength;
    int32 NumLinks;
    FVector HingeRotationAxis;
    bool bEnableRotationLimit;
    bool bInitialized;
 
public:
    FIKChain()
        : MyAnimInstanceProxy(nullptr)
        , TotalChainLength(0.0)
        , NumLinks(INDEX_NONE)
        , HingeRotationAxis(FVector::ZeroVector)
        , bEnableRotationLimit(false)
        , bInitialized(false)
    {}
 
    void InitializeFromLegData(FAnimLegIKData& InLegData, FAnimInstanceProxy* InAnimInstanceProxy);
    void ReachTarget(
        const FVector& InTargetLocation,
        double InReachPrecision,
        int32 InMaxIterations,
        float SoftPercentLength,
        float SoftAlpha);
    void ApplyTwistOffset(const float InTwistOffsetDegrees);
 
    double GetMaximumReach() const
    {
        return TotalChainLength;
    }
 
private:
    void OrientAllLinksToDirection(const FVector& InDirection);
    void SolveTwoBoneIK(const FVector& InTargetLocation);
    void SolveFABRIK(const FVector& InTargetLocation, double InReachPrecision, int32 InMaxIterations);
 
    static void FABRIK_ForwardReach(const FVector& InTargetLocation, FIKChain& IKChain);
    static void FABRIK_BackwardReach(const FVector& InRootTargetLocation, FIKChain& IKChain);
    static void FABRIK_ApplyLinkConstraints_Forward(FIKChain& IKChain, int32 LinkIndex);
    static void FABRIK_ApplyLinkConstraints_Backward(FIKChain& IKChain, int32 LinkIndex);
 
    static void DrawDebugIKChain(const FIKChain& IKChain, const FColor& InColor);
};
 
USTRUCT()
struct FAnimLegIKDefinition
{
    GENERATED_USTRUCT_BODY()
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    FBoneReference IKFootBone;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    FBoneReference FKFootBone;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    int32 NumBonesInLimb;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    float MinRotationAngle;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    TEnumAsByte<EAxis::Type> FootBoneForwardAxis;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    TEnumAsByte<EAxis::Type> HingeRotationAxis;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    bool bEnableRotationLimit;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    bool bEnableKneeTwistCorrection;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    FName TwistOffsetCurveName;
 
    FAnimLegIKDefinition()
        : NumBonesInLimb(2)
        , MinRotationAngle(15.f)
        , FootBoneForwardAxis(EAxis::Y)
        , HingeRotationAxis(EAxis::None)
        , bEnableRotationLimit(false)
        , bEnableKneeTwistCorrection(true)
        , TwistOffsetCurveName(NAME_None)
    {}
};
 
USTRUCT()
struct FAnimLegIKData
{
    GENERATED_USTRUCT_BODY()
 
public:
    FTransform IKFootTransform;
    FAnimLegIKDefinition* LegDefPtr;
    FCompactPoseBoneIndex IKFootBoneIndex;
    float TwistOffsetDegrees;
    int32 NumBones;
    TArray<FCompactPoseBoneIndex> FKLegBoneIndices;
    TArray<FTransform> FKLegBoneTransforms;
 
    FIKChain IKChain;
 
public:
    void InitializeTransforms(FAnimInstanceProxy* MyAnimInstanceProxy, FCSPose<FCompactPose>& MeshBases);
 
    FAnimLegIKData()
        : IKFootTransform(FTransform::Identity)
        , LegDefPtr(nullptr)
        , IKFootBoneIndex(INDEX_NONE)
        , TwistOffsetDegrees(0.0f)
        , NumBones(INDEX_NONE)
    {}
};
 
USTRUCT()
struct FAnimNode_LegIK : public FAnimNode_SkeletalControlBase
{
    GENERATED_USTRUCT_BODY()
 
    ANIMGRAPHRUNTIME_API FAnimNode_LegIK();
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    float ReachPrecision;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    int32 MaxIterations;
 
    UPROPERTY(EditAnywhere, Category = "Settings", meta = (PinHiddenByDefault, UIMin = "0.01", UIMax = "1", ClampMin = "0.01", ClampMax = "1"))
    float SoftPercentLength;
 
    UPROPERTY(EditAnywhere, Category = "Settings", meta = (PinHiddenByDefault, UIMin = "0.0", UIMax = "1", ClampMin = "0.0", ClampMax = "1"))
    float SoftAlpha;
 
    UPROPERTY(EditAnywhere, Category = "Settings")
    TArray<FAnimLegIKDefinition> LegsDefinition;
 
    TArray<FAnimLegIKData> LegsData;
 
    FAnimInstanceProxy* MyAnimInstanceProxy;
 
public:
    // FAnimNode_Base interface
    ANIMGRAPHRUNTIME_API virtual void GatherDebugData(FNodeDebugData& DebugData) override;
    // End of FAnimNode_Base interface
 
    // FAnimNode_SkeletalControlBase interface
    ANIMGRAPHRUNTIME_API virtual void Initialize_AnyThread(const FAnimationInitializeContext& Context) override;
    ANIMGRAPHRUNTIME_API virtual void EvaluateSkeletalControl_AnyThread(FComponentSpacePoseContext& Output, TArray<FBoneTransform>& OutBoneTransforms) override;
    ANIMGRAPHRUNTIME_API virtual bool IsValidToEvaluate(const USkeleton* Skeleton, const FBoneContainer& RequiredBones) override;
    // End of FAnimNode_SkeletalControlBase interface
 
    ANIMGRAPHRUNTIME_API bool OrientLegTowardsIK(FAnimLegIKData& InLegData);
    ANIMGRAPHRUNTIME_API bool DoLegReachIK(FAnimLegIKData& InLegData);
    ANIMGRAPHRUNTIME_API bool AdjustKneeTwist(FAnimLegIKData& InLegData);
 
private:
    // FAnimNode_SkeletalControlBase interface
    ANIMGRAPHRUNTIME_API virtual void InitializeBoneReferences(const FBoneContainer& RequiredBones) override;
    // End of FAnimNode_SkeletalControlBase interface
};