PBDBendingConstraints.h

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// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
 
#include "Chaos/PBDBendingConstraintsBase.h"
#include "Chaos/CollectionPropertyFacade.h"
 
namespace Chaos::Softs
{
 
class FPBDBendingConstraints : public FPBDBendingConstraintsBase
{
    typedef FPBDBendingConstraintsBase Base;
 
public:
    static bool IsEnabled(const FCollectionPropertyConstFacade& PropertyCollection)
    {
        return IsBendingElementStiffnessEnabled(PropertyCollection, false);
    }   
    
    FPBDBendingConstraints(const FSolverParticlesRange& InParticles,
        TArray<TVec4<int32>>&& InConstraints,
        const TMap<FString, TConstArrayView<FRealSingle>>& WeightMaps,
        const FCollectionPropertyConstFacade& PropertyCollection,
        bool bTrimKinematicConstraints = false)
        : Base(
            InParticles,
            MoveTemp(InConstraints),
            WeightMaps.FindRef(GetBendingElementStiffnessString(PropertyCollection, BendingElementStiffnessName.ToString())),
            WeightMaps.FindRef(GetBucklingRatioString(PropertyCollection, BucklingRatioName.ToString())),
            WeightMaps.FindRef(GetBucklingStiffnessString(PropertyCollection, BucklingStiffnessName.ToString())),
            GetRestAngleMapFromCollection(WeightMaps, PropertyCollection),
            FSolverVec2(GetWeightedFloatBendingElementStiffness(PropertyCollection, 1.f)),
            FSolverVec2(GetWeightedFloatBucklingRatio(PropertyCollection, 0.f)),  // BucklingRatio is clamped in base class
            FSolverVec2(GetWeightedFloatBucklingStiffness(PropertyCollection, 1.f)),
            GetRestAngleValueFromCollection(PropertyCollection),
            (ERestAngleConstructionType)GetRestAngleType(PropertyCollection, (int32)ERestAngleConstructionType::Use3DRestAngles),
            bTrimKinematicConstraints)
        , BendingElementStiffnessIndex(PropertyCollection)
        , BucklingRatioIndex(PropertyCollection)
        , BucklingStiffnessIndex(PropertyCollection)
        , FlatnessRatioIndex(PropertyCollection)
        , RestAngleIndex(PropertyCollection)
        , RestAngleTypeIndex(PropertyCollection)
    {
        InitColor(InParticles);
    }
 
    FPBDBendingConstraints(const FSolverParticles& InParticles,
        int32 InParticleOffset,
        int32 InParticleCount,
        TArray<TVec4<int32>>&& InConstraints,
        const TMap<FString, TConstArrayView<FRealSingle>>& WeightMaps,
        const FCollectionPropertyConstFacade& PropertyCollection,
        bool bTrimKinematicConstraints = false)
        : Base(
            InParticles,
            InParticleOffset,
            InParticleCount,
            MoveTemp(InConstraints),
            WeightMaps.FindRef(GetBendingElementStiffnessString(PropertyCollection, BendingElementStiffnessName.ToString())),
            WeightMaps.FindRef(GetBucklingRatioString(PropertyCollection, BucklingRatioName.ToString())),
            WeightMaps.FindRef(GetBucklingStiffnessString(PropertyCollection, BucklingStiffnessName.ToString())),
            GetRestAngleMapFromCollection(WeightMaps, PropertyCollection),
            FSolverVec2(GetWeightedFloatBendingElementStiffness(PropertyCollection, 1.f)),
            FSolverVec2(GetWeightedFloatBucklingRatio(PropertyCollection, 0.f)),  // BucklingRatio is clamped in base class
            FSolverVec2(GetWeightedFloatBucklingStiffness(PropertyCollection, 1.f)),
            GetRestAngleValueFromCollection(PropertyCollection),
            (ERestAngleConstructionType)GetRestAngleType(PropertyCollection, (int32)ERestAngleConstructionType::Use3DRestAngles),
            bTrimKinematicConstraints)
        , BendingElementStiffnessIndex(PropertyCollection)
        , BucklingRatioIndex(PropertyCollection)
        , BucklingStiffnessIndex(PropertyCollection)
        , FlatnessRatioIndex(PropertyCollection)
        , RestAngleIndex(PropertyCollection)
        , RestAngleTypeIndex(PropertyCollection)
    {
        InitColor(InParticles);
    }
 
    FPBDBendingConstraints(const FSolverParticles& InParticles,
        int32 ParticleOffset,
        int32 ParticleCount,
        TArray<TVec4<int32>>&& InConstraints,
        const TConstArrayView<FRealSingle>& StiffnessMultipliers,
        const TConstArrayView<FRealSingle>& BucklingRatioMultipliers,
        const TConstArrayView<FRealSingle>& BucklingStiffnessMultipliers,
        const TConstArrayView<FRealSingle>& RestAngleMap,
        const FSolverVec2& InStiffness,
        const FSolverVec2& InBucklingRatio,
        const FSolverVec2& InBucklingStiffness,
        const FSolverVec2& RestAngleValue,
        ERestAngleConstructionType RestAngleConstructionType,
        bool bTrimKinematicConstraints = false)
        : Base(
            InParticles,
            ParticleOffset,
            ParticleCount,
            MoveTemp(InConstraints),
            StiffnessMultipliers,
            BucklingRatioMultipliers,
            BucklingStiffnessMultipliers,
            RestAngleMap,
            InStiffness,
            InBucklingRatio,
            InBucklingStiffness,
            RestAngleValue,
            RestAngleConstructionType,
            bTrimKinematicConstraints)
        , BendingElementStiffnessIndex(ForceInit)
        , BucklingRatioIndex(ForceInit)
        , BucklingStiffnessIndex(ForceInit)
        , FlatnessRatioIndex(ForceInit)
        , RestAngleIndex(ForceInit)
        , RestAngleTypeIndex(ForceInit)
    {
        InitColor(InParticles);
    }
 
    UE_DEPRECATED(5.5, "Use constructor with BucklingRatioMultipliers")
    FPBDBendingConstraints(const FSolverParticles& InParticles,
        int32 ParticleOffset,
        int32 ParticleCount,
        TArray<TVec4<int32>>&& InConstraints,
        const TConstArrayView<FRealSingle>& StiffnessMultipliers,
        const TConstArrayView<FRealSingle>& BucklingStiffnessMultipliers,
        const FSolverVec2& InStiffness,
        const FSolverReal InBucklingRatio,
        const FSolverVec2& InBucklingStiffness,
        bool bTrimKinematicConstraints = false)
        : FPBDBendingConstraints(
            InParticles, 
            ParticleOffset, 
            ParticleCount, 
            MoveTemp(InConstraints), 
            StiffnessMultipliers, 
            TConstArrayView<FRealSingle>(), 
            BucklingStiffnessMultipliers,
            TConstArrayView<FRealSingle>(),
            InStiffness, 
            FSolverVec2(InBucklingRatio), 
            InBucklingStiffness,
            FSolverVec2((FSolverReal)0.f),
            ERestAngleConstructionType::Use3DRestAngles,
            bTrimKinematicConstraints)
    {}
 
    virtual ~FPBDBendingConstraints() override {}
 
    using Base::SetProperties;
 
    CHAOS_API void SetProperties(
        const FCollectionPropertyConstFacade& PropertyCollection,
        const TMap<FString, TConstArrayView<FRealSingle>>& WeightMaps);
 
    template<typename SolverParticlesOrRange>
    CHAOS_API void Apply(SolverParticlesOrRange& InParticles, const FSolverReal Dt) const;
 
    const TArray<int32>& GetConstraintsPerColorStartIndex() const { return ConstraintsPerColorStartIndex; }
 
    void ResetRestLengths(const TConstArrayView<FSolverVec3>& Positions,
        const FCollectionPropertyConstFacade& PropertyCollection,
        const TMap<FString, TConstArrayView<FRealSingle>>& WeightMaps)
    {
        CalculateRestAngles(Positions, ParticleOffset, ParticleCount,
            GetRestAngleMapFromCollection(WeightMaps, PropertyCollection),
            GetRestAngleValueFromCollection(PropertyCollection),
            (ERestAngleConstructionType)GetRestAngleType(PropertyCollection, (int32)ERestAngleConstructionType::Use3DRestAngles));
    }
 
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(BendingElementStiffness, float);
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(BucklingRatio, float);
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(BucklingStiffness, float);
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(FlatnessRatio, float);
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(RestAngle, float);
    UE_CHAOS_DECLARE_INDEXLESS_PROPERTYCOLLECTION_NAME(RestAngleType, int32);
 
private:
    template<typename SolverParticlesOrRange>
    CHAOS_API void InitColor(const SolverParticlesOrRange& InParticles);
    template<typename SolverParticlesOrRange>
    void ApplyHelper(SolverParticlesOrRange& InParticles, const FSolverReal Dt, const int32 ConstraintIndex, const FSolverReal ExpStiffnessValue, const FSolverReal ExpBucklingValue) const;
 
    TConstArrayView<FRealSingle> GetRestAngleMapFromCollection(
        const TMap<FString, TConstArrayView<FRealSingle>>& WeightMaps,
        const FCollectionPropertyConstFacade& PropertyCollection)
    {
        const ERestAngleConstructionType ConstructionType = (ERestAngleConstructionType)GetRestAngleType(PropertyCollection, (int32)ERestAngleConstructionType::Use3DRestAngles);
 
        switch (ConstructionType)
        {
        default:
        case ERestAngleConstructionType::Use3DRestAngles:
            return TConstArrayView<FRealSingle>(); // Unused
        case ERestAngleConstructionType::FlatnessRatio:
            return WeightMaps.FindRef(GetFlatnessRatioString(PropertyCollection, FlatnessRatioName.ToString()));
        case ERestAngleConstructionType::ExplicitRestAngles:
            return WeightMaps.FindRef(GetRestAngleString(PropertyCollection, RestAngleName.ToString()));
        }
    }
 
    FSolverVec2 GetRestAngleValueFromCollection(const FCollectionPropertyConstFacade& PropertyCollection)
    {
        const ERestAngleConstructionType ConstructionType = (ERestAngleConstructionType)GetRestAngleType(PropertyCollection, (int32)ERestAngleConstructionType::Use3DRestAngles);
 
        switch (ConstructionType)
        {
        default:
        case ERestAngleConstructionType::Use3DRestAngles:
            return FSolverVec2(0.f); // Unused
        case ERestAngleConstructionType::FlatnessRatio:
            return FSolverVec2(GetWeightedFloatFlatnessRatio(PropertyCollection, 0.f));
        case ERestAngleConstructionType::ExplicitRestAngles:
            return FSolverVec2(GetWeightedFloatRestAngle(PropertyCollection, 0.f));
        }
    }
 
    using Base::Constraints;
    using Base::ParticleOffset;
    using Base::ParticleCount;
    using Base::Stiffness;
    using Base::BucklingRatioWeighted;
    using Base::BucklingStiffness;
 
    TArray<int32> ConstraintsPerColorStartIndex; // Constraints are ordered so each batch is contiguous. This is ColorNum + 1 length so it can be used as start and end.
 
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(BendingElementStiffness, float);
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(BucklingRatio, float);
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(BucklingStiffness, float);
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(FlatnessRatio, float);
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(RestAngle, float);
    UE_CHAOS_DECLARE_INDEXED_PROPERTYCOLLECTION_NAME(RestAngleType, int32);
};
 
}  // End namespace Chaos::Softs