ContactConstraintManager.h

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// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
// SPDX-License-Identifier: MIT
 
#pragma once
 
#include <Jolt/Core/StaticArray.h>
#include <Jolt/Core/LockFreeHashMap.h>
#include <Jolt/Physics/EPhysicsUpdateError.h>
#include <Jolt/Physics/Body/BodyPair.h>
#include <Jolt/Physics/Collision/Shape/SubShapeIDPair.h>
#include <Jolt/Physics/Collision/ManifoldBetweenTwoFaces.h>
#include <Jolt/Physics/Constraints/ConstraintPart/AxisConstraintPart.h>
#include <Jolt/Physics/Constraints/ConstraintPart/DualAxisConstraintPart.h>
#include <Jolt/Core/HashCombine.h>
#include <Jolt/Core/NonCopyable.h>
 
JPH_SUPPRESS_WARNINGS_STD_BEGIN
#include <atomic>
JPH_SUPPRESS_WARNINGS_STD_END
 
JPH_NAMESPACE_BEGIN
 
struct PhysicsSettings;
class PhysicsUpdateContext;
 
class ContactConstraintManager : public NonCopyable
{
public:
    JPH_OVERRIDE_NEW_DELETE
 
    explicit                    ContactConstraintManager(const PhysicsSettings &inPhysicsSettings);
                                ~ContactConstraintManager();
 
    void                        Init(uint inMaxBodyPairs, uint inMaxContactConstraints);
 
    void                        SetContactListener(ContactListener *inListener)                     { mContactListener = inListener; }
    ContactListener *           GetContactListener() const                                          { return mContactListener; }
 
    using CombineFunction = float (*)(const Body &inBody1, const SubShapeID &inSubShapeID1, const Body &inBody2, const SubShapeID &inSubShapeID2);
 
    void                        SetCombineFriction(CombineFunction inCombineFriction)               { mCombineFriction = inCombineFriction; }
 
    void                        SetCombineRestitution(CombineFunction inCombineRestitution)         { mCombineRestitution = inCombineRestitution; }
 
    uint32                      GetMaxConstraints() const                                           { return mMaxConstraints; }
 
    inline ValidateResult       ValidateContactPoint(const Body &inBody1, const Body &inBody2, RVec3Arg inBaseOffset, const CollideShapeResult &inCollisionResult) const    
    { 
        if (mContactListener == nullptr) 
            return ValidateResult::AcceptAllContactsForThisBodyPair; 
 
        return mContactListener->OnContactValidate(inBody1, inBody2, inBaseOffset, inCollisionResult); 
    }
 
    void                        PrepareConstraintBuffer(PhysicsUpdateContext *inContext);
 
    static const int            MaxContactPoints = 4;
 
    class ContactAllocator : public LFHMAllocatorContext
    {
    public:
        using LFHMAllocatorContext::LFHMAllocatorContext;
 
        uint                    mNumBodyPairs = 0;                                                  
        uint                    mNumManifolds = 0;                                                  
        EPhysicsUpdateError     mErrors = EPhysicsUpdateError::None;                                
    };
 
    ContactAllocator            GetContactAllocator()                                               { return mCache[mCacheWriteIdx].GetContactAllocator(); }
 
    void                        GetContactsFromCache(ContactAllocator &ioContactAllocator, Body &inBody1, Body &inBody2, bool &outPairHandled, bool &outConstraintCreated);
 
    using BodyPairHandle = void *;
 
    BodyPairHandle              AddBodyPair(ContactAllocator &ioContactAllocator, const Body &inBody1, const Body &inBody2);
 
    bool                        AddContactConstraint(ContactAllocator &ioContactAllocator, BodyPairHandle inBodyPair, Body &inBody1, Body &inBody2, const ContactManifold &inManifold);
 
    void                        FinalizeContactCacheAndCallContactPointRemovedCallbacks(uint inExpectedNumBodyPairs, uint inExpectedNumManifolds);
 
    bool                        WereBodiesInContact(const BodyID &inBody1ID, const BodyID &inBody2ID) const;
 
    uint32                      GetNumConstraints() const                                           { return min<uint32>(mNumConstraints, mMaxConstraints); }
 
    void                        SortContacts(uint32 *inConstraintIdxBegin, uint32 *inConstraintIdxEnd) const;
 
    inline void                 GetAffectedBodies(uint32 inConstraintIdx, const Body *&outBody1, const Body *&outBody2) const
    {
        const ContactConstraint &constraint = mConstraints[inConstraintIdx];
        outBody1 = constraint.mBody1;
        outBody2 = constraint.mBody2;
    }
 
    void                        SetupVelocityConstraints(const uint32 *inConstraintIdxBegin, const uint32 *inConstraintIdxEnd, float inDeltaTime);
 
    void                        WarmStartVelocityConstraints(const uint32 *inConstraintIdxBegin, const uint32 *inConstraintIdxEnd, float inWarmStartImpulseRatio);
 
    bool                        SolveVelocityConstraints(const uint32 *inConstraintIdxBegin, const uint32 *inConstraintIdxEnd);
 
    void                        StoreAppliedImpulses(const uint32 *inConstraintIdxBegin, const uint32 *inConstraintIdxEnd) const;
 
    bool                        SolvePositionConstraints(const uint32 *inConstraintIdxBegin, const uint32 *inConstraintIdxEnd);
 
    void                        RecycleConstraintBuffer();
 
    void                        FinishConstraintBuffer();
 
    void                        OnCCDContactAdded(ContactAllocator &ioContactAllocator, const Body &inBody1, const Body &inBody2, const ContactManifold &inManifold, ContactSettings &outSettings);
 
#ifdef JPH_DEBUG_RENDERER
    // Drawing properties
    static bool                 sDrawContactPoint;
    static bool                 sDrawSupportingFaces;
    static bool                 sDrawContactPointReduction;
    static bool                 sDrawContactManifolds;
#endif // JPH_DEBUG_RENDERER
 
    void                        SaveState(StateRecorder &inStream) const;
 
    bool                        RestoreState(StateRecorder &inStream);
 
private:
    class CachedContactPoint
    {
    public:
        void                    SaveState(StateRecorder &inStream) const;
        void                    RestoreState(StateRecorder &inStream);
 
        Float3                  mPosition1;
        Float3                  mPosition2;
 
        float                   mNonPenetrationLambda;
        Vector<2>               mFrictionLambda;
    };
 
    static_assert(sizeof(CachedContactPoint) == 36, "Unexpected size");
    static_assert(alignof(CachedContactPoint) == 4, "Assuming 4 byte aligned");
    
    class CachedManifold
    {
    public:
        static int              sGetRequiredExtraSize(int inNumContactPoints)                       { return max(0, inNumContactPoints - 1) * sizeof(CachedContactPoint); }
 
        static int              sGetRequiredTotalSize(int inNumContactPoints)                       { return sizeof(CachedManifold) + sGetRequiredExtraSize(inNumContactPoints); }
 
        void                    SaveState(StateRecorder &inStream) const;
        void                    RestoreState(StateRecorder &inStream);
 
        uint32                  mNextWithSameBodyPair;
 
        Float3                  mContactNormal;
 
        enum class EFlags : uint16
        {
            ContactPersisted    = 1,                                                                
            CCDContact          = 2                                                                 
        };
 
        mutable atomic<uint16>  mFlags { 0 };
 
        uint16                  mNumContactPoints;
 
        CachedContactPoint      mContactPoints[1];
    };
 
    static_assert(sizeof(CachedManifold) == 56, "This structure is expect to not contain any waste due to alignment");
    static_assert(alignof(CachedManifold) == 4, "Assuming 4 byte aligned");
 
    using ManifoldMap = LockFreeHashMap<SubShapeIDPair, CachedManifold>;
    using MKeyValue = ManifoldMap::KeyValue;
    using MKVAndCreated = pair<MKeyValue *, bool>;
 
    class CachedBodyPair
    {
    public:
        void                    SaveState(StateRecorder &inStream) const;
        void                    RestoreState(StateRecorder &inStream);
 
        Float3                  mDeltaPosition;
 
        Float3                  mDeltaRotation;
 
        uint32                  mFirstCachedManifold;
    };
 
    static_assert(sizeof(CachedBodyPair) == 28, "Unexpected size"); 
    static_assert(alignof(CachedBodyPair) == 4, "Assuming 4 byte aligned");
 
    using BodyPairMap = LockFreeHashMap<BodyPair, CachedBodyPair>;
    using BPKeyValue = BodyPairMap::KeyValue;
 
    class ManifoldCache
    {
    public:
        void                    Init(uint inMaxBodyPairs, uint inMaxContactConstraints, uint inCachedManifoldsSize);
 
        void                    Clear();
 
        void                    Prepare(uint inExpectedNumBodyPairs, uint inExpectedNumManifolds);
 
        ContactAllocator        GetContactAllocator()                       { return ContactAllocator(mAllocator, cAllocatorBlockSize); }
 
        const MKeyValue *       Find(const SubShapeIDPair &inKey, uint64 inKeyHash) const;
        MKeyValue *             Create(ContactAllocator &ioContactAllocator, const SubShapeIDPair &inKey, uint64 inKeyHash, int inNumContactPoints);
        MKVAndCreated           FindOrCreate(ContactAllocator &ioContactAllocator, const SubShapeIDPair &inKey, uint64 inKeyHash, int inNumContactPoints);
        uint32                  ToHandle(const MKeyValue *inKeyValue) const;
        const MKeyValue *       FromHandle(uint32 inHandle) const;
 
        const BPKeyValue *      Find(const BodyPair &inKey, uint64 inKeyHash) const;
        BPKeyValue *            Create(ContactAllocator &ioContactAllocator, const BodyPair &inKey, uint64 inKeyHash);
        void                    GetAllBodyPairsSorted(Array<const BPKeyValue *> &outAll) const;
        void                    GetAllManifoldsSorted(const CachedBodyPair &inBodyPair, Array<const MKeyValue *> &outAll) const;
        void                    GetAllCCDManifoldsSorted(Array<const MKeyValue *> &outAll) const;
        void                    ContactPointRemovedCallbacks(ContactListener *inListener);
 
#ifdef JPH_ENABLE_ASSERTS
        uint                    GetNumManifolds() const                     { return mCachedManifolds.GetNumKeyValues(); }
 
        uint                    GetNumBodyPairs() const                     { return mCachedBodyPairs.GetNumKeyValues(); }
 
        void                    Finalize();
#endif
 
        void                    SaveState(StateRecorder &inStream) const;
        bool                    RestoreState(const ManifoldCache &inReadCache, StateRecorder &inStream);
 
    private:
        static constexpr uint32 cAllocatorBlockSize = 4096;
 
        LFHMAllocator           mAllocator;
 
        ManifoldMap             mCachedManifolds { mAllocator };
 
        BodyPairMap             mCachedBodyPairs { mAllocator };
 
#ifdef JPH_ENABLE_ASSERTS
        bool                    mIsFinalized = false;                       
#endif
    };
 
    ManifoldCache               mCache[2];                                  
    int                         mCacheWriteIdx = 0;                         
 
    class WorldContactPoint
    {
    public:
        void                    CalculateNonPenetrationConstraintProperties(float inDeltaTime, const Body &inBody1, const Body &inBody2, RVec3Arg inWorldSpacePosition1, RVec3Arg inWorldSpacePosition2, Vec3Arg inWorldSpaceNormal);
        template <EMotionType Type1, EMotionType Type2>
        JPH_INLINE void         CalculateFrictionAndNonPenetrationConstraintProperties(float inDeltaTime, const Body &inBody1, const Body &inBody2, Mat44Arg inInvI1, Mat44Arg inInvI2, RVec3Arg inWorldSpacePosition1, RVec3Arg inWorldSpacePosition2, Vec3Arg inWorldSpaceNormal, Vec3Arg inWorldSpaceTangent1, Vec3Arg inWorldSpaceTangent2, float inCombinedRestitution, float inCombinedFriction, float inMinVelocityForRestitution);
 
        AxisConstraintPart      mNonPenetrationConstraint;
        AxisConstraintPart      mFrictionConstraint1;
        AxisConstraintPart      mFrictionConstraint2;
        
        CachedContactPoint *    mContactPoint;
    };
 
    using WorldContactPoints = StaticArray<WorldContactPoint, MaxContactPoints>;
 
    class ContactConstraint
    {
    public:
    #ifdef JPH_DEBUG_RENDERER
        void                    Draw(DebugRenderer *inRenderer, ColorArg inManifoldColor) const;
    #endif // JPH_DEBUG_RENDERER
 
        JPH_INLINE void         GetTangents(Vec3 &outTangent1, Vec3 &outTangent2) const
        {
            outTangent1 = mWorldSpaceNormal.GetNormalizedPerpendicular();
            outTangent2 = mWorldSpaceNormal.Cross(outTangent1);
        }
 
        Vec3                    mWorldSpaceNormal;
        Body *                  mBody1;
        Body *                  mBody2;
        uint64                  mSortKey;
        float                   mCombinedFriction;
        float                   mCombinedRestitution;
        WorldContactPoints      mContactPoints;
    };
 
    template <EMotionType Type1, EMotionType Type2>
    JPH_INLINE void             TemplatedCalculateFrictionAndNonPenetrationConstraintProperties(ContactConstraint &ioConstraint, float inDeltaTime, RMat44Arg inTransformBody1, RMat44Arg inTransformBody2, const Body &inBody1, const Body &inBody2, Mat44Arg inInvI1, Mat44Arg inInvI2);
 
    inline void                 CalculateFrictionAndNonPenetrationConstraintProperties(ContactConstraint &ioConstraint, float inDeltaTime, RMat44Arg inTransformBody1, RMat44Arg inTransformBody2, const Body &inBody1, const Body &inBody2);
 
    template <EMotionType Type1, EMotionType Type2>
    bool                        TemplatedAddContactConstraint(ContactAllocator &ioContactAllocator, BodyPairHandle inBodyPairHandle, Body &inBody1, Body &inBody2, const ContactManifold &inManifold, Mat44Arg inInvI1, Mat44Arg inInvI2);
 
    template <EMotionType Type1, EMotionType Type2>
    JPH_INLINE static void      sWarmStartConstraint(ContactConstraint &ioConstraint, MotionProperties *ioMotionProperties1, MotionProperties *ioMotionProperties2, float inWarmStartImpulseRatio);
 
    template <EMotionType Type1, EMotionType Type2>
    JPH_INLINE static bool      sSolveVelocityConstraint(ContactConstraint &ioConstraint, MotionProperties *ioMotionProperties1, MotionProperties *ioMotionProperties2);
 
    const PhysicsSettings &     mPhysicsSettings;
 
    ContactListener *           mContactListener = nullptr;
 
    CombineFunction             mCombineFriction = [](const Body &inBody1, const SubShapeID &, const Body &inBody2, const SubShapeID &) { return sqrt(inBody1.GetFriction() * inBody2.GetFriction()); };
    CombineFunction             mCombineRestitution = [](const Body &inBody1, const SubShapeID &, const Body &inBody2, const SubShapeID &) { return max(inBody1.GetRestitution(), inBody2.GetRestitution()); };
 
    ContactConstraint *         mConstraints = nullptr;
    uint32                      mMaxConstraints = 0;
    atomic<uint32>              mNumConstraints { 0 };
 
    PhysicsUpdateContext *      mUpdateContext;
};
 
JPH_NAMESPACE_END