btSequentialImpulseConstraintSolverMt.h

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/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it freely,
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef BT_SEQUENTIAL_IMPULSE_CONSTRAINT_SOLVER_MT_H
#define BT_SEQUENTIAL_IMPULSE_CONSTRAINT_SOLVER_MT_H

#include "btSequentialImpulseConstraintSolver.h"
#include "btBatchedConstraints.h"
#include "LinearMath/btThreads.h"

ATTRIBUTE_ALIGNED16(class) btSequentialImpulseConstraintSolverMt : public btSequentialImpulseConstraintSolver
{
public:
        virtual void solveGroupCacheFriendlySplitImpulseIterations(btCollisionObject** bodies,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer) BT_OVERRIDE;
        virtual btScalar solveSingleIteration(int iteration, btCollisionObject** bodies ,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer) BT_OVERRIDE;
        virtual btScalar solveGroupCacheFriendlySetup(btCollisionObject** bodies,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer) BT_OVERRIDE;
        virtual btScalar solveGroupCacheFriendlyFinish(btCollisionObject** bodies, int numBodies, const btContactSolverInfo& infoGlobal) BT_OVERRIDE;

    // temp struct used to collect info from persistent manifolds into a cache-friendly struct using multiple threads
    struct btContactManifoldCachedInfo
    {
        static const int MAX_NUM_CONTACT_POINTS = 4;

        int numTouchingContacts;
        int solverBodyIds[ 2 ];
        int contactIndex;
        int rollingFrictionIndex;
        bool contactHasRollingFriction[ MAX_NUM_CONTACT_POINTS ];
        btManifoldPoint* contactPoints[ MAX_NUM_CONTACT_POINTS ];
    };
    // temp struct used for setting up joint constraints in parallel
    struct JointParams
    {
        int m_solverConstraint;
        int m_solverBodyA;
        int m_solverBodyB;
    };
    void internalInitMultipleJoints(btTypedConstraint** constraints, int iBegin, int iEnd);
    void internalConvertMultipleJoints( const btAlignedObjectArray<JointParams>& jointParamsArray, btTypedConstraint** constraints, int iBegin, int iEnd, const btContactSolverInfo& infoGlobal );

    // parameters to control batching
    static bool s_allowNestedParallelForLoops;        // whether to allow nested parallel operations
    static int s_minimumContactManifoldsForBatching;  // don't even try to batch if fewer manifolds than this
    static btBatchedConstraints::BatchingMethod s_contactBatchingMethod;
    static btBatchedConstraints::BatchingMethod s_jointBatchingMethod;
    static int s_minBatchSize;  // desired number of constraints per batch
    static int s_maxBatchSize;

protected:
    static const int CACHE_LINE_SIZE = 64;

    btBatchedConstraints m_batchedContactConstraints;
    btBatchedConstraints m_batchedJointConstraints;
    int m_numFrictionDirections;
    bool m_useBatching;
    bool m_useObsoleteJointConstraints;
    btAlignedObjectArray<btContactManifoldCachedInfo> m_manifoldCachedInfoArray;
    btAlignedObjectArray<int> m_rollingFrictionIndexTable;  // lookup table mapping contact index to rolling friction index
    btSpinMutex m_bodySolverArrayMutex;
    char m_antiFalseSharingPadding[CACHE_LINE_SIZE]; // padding to keep mutexes in separate cachelines
    btSpinMutex m_kinematicBodyUniqueIdToSolverBodyTableMutex;
    btAlignedObjectArray<char> m_scratchMemory;

    virtual void randomizeConstraintOrdering( int iteration, int numIterations );
    virtual btScalar resolveAllJointConstraints( int iteration );
    virtual btScalar resolveAllContactConstraints();
    virtual btScalar resolveAllContactFrictionConstraints();
    virtual btScalar resolveAllContactConstraintsInterleaved();
    virtual btScalar resolveAllRollingFrictionConstraints();

    virtual void setupBatchedContactConstraints();
    virtual void setupBatchedJointConstraints();
    virtual void convertJoints(btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal) BT_OVERRIDE;
        virtual void convertContacts(btPersistentManifold** manifoldPtr, int numManifolds, const btContactSolverInfo& infoGlobal) BT_OVERRIDE;
    virtual void convertBodies(btCollisionObject** bodies, int numBodies, const btContactSolverInfo& infoGlobal) BT_OVERRIDE;

        int getOrInitSolverBodyThreadsafe(btCollisionObject& body, btScalar timeStep);
    void allocAllContactConstraints(btPersistentManifold** manifoldPtr, int numManifolds, const btContactSolverInfo& infoGlobal);
    void setupAllContactConstraints(const btContactSolverInfo& infoGlobal);
    void randomizeBatchedConstraintOrdering( btBatchedConstraints* batchedConstraints );

public:

        BT_DECLARE_ALIGNED_ALLOCATOR();

        btSequentialImpulseConstraintSolverMt();
        virtual ~btSequentialImpulseConstraintSolverMt();

    btScalar resolveMultipleJointConstraints( const btAlignedObjectArray<int>& consIndices, int batchBegin, int batchEnd, int iteration );
    btScalar resolveMultipleContactConstraints( const btAlignedObjectArray<int>& consIndices, int batchBegin, int batchEnd );
    btScalar resolveMultipleContactSplitPenetrationImpulseConstraints( const btAlignedObjectArray<int>& consIndices, int batchBegin, int batchEnd );
    btScalar resolveMultipleContactFrictionConstraints( const btAlignedObjectArray<int>& consIndices, int batchBegin, int batchEnd );
    btScalar resolveMultipleContactRollingFrictionConstraints( const btAlignedObjectArray<int>& consIndices, int batchBegin, int batchEnd );
    btScalar resolveMultipleContactConstraintsInterleaved( const btAlignedObjectArray<int>& contactIndices, int batchBegin, int batchEnd );

    void internalCollectContactManifoldCachedInfo(btContactManifoldCachedInfo* cachedInfoArray, btPersistentManifold** manifoldPtr, int numManifolds, const btContactSolverInfo& infoGlobal);
    void internalAllocContactConstraints(const btContactManifoldCachedInfo* cachedInfoArray, int numManifolds);
    void internalSetupContactConstraints(int iContactConstraint, const btContactSolverInfo& infoGlobal);
    void internalConvertBodies(btCollisionObject** bodies, int iBegin, int iEnd, const btContactSolverInfo& infoGlobal);
    void internalWriteBackContacts(int iBegin, int iEnd, const btContactSolverInfo& infoGlobal);
    void internalWriteBackJoints(int iBegin, int iEnd, const btContactSolverInfo& infoGlobal);
    void internalWriteBackBodies(int iBegin, int iEnd, const btContactSolverInfo& infoGlobal);
};




#endif //BT_SEQUENTIAL_IMPULSE_CONSTRAINT_SOLVER_MT_H