btContactSolverInfo.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_CONTACT_SOLVER_INFO
#define BT_CONTACT_SOLVER_INFO

enum    btSolverMode
{
        SOLVER_RANDMIZE_ORDER = 1,
        SOLVER_FRICTION_SEPARATE = 2,
        SOLVER_USE_WARMSTARTING = 4,
        SOLVER_USE_FRICTION_WARMSTARTING = 8,
        SOLVER_USE_2_FRICTION_DIRECTIONS = 16,
        SOLVER_ENABLE_FRICTION_DIRECTION_CACHING = 32,
        SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION = 64,
        SOLVER_CACHE_FRIENDLY = 128,
        SOLVER_SIMD = 256,      //enabled for Windows, the solver innerloop is branchless SIMD, 40% faster than FPU/scalar version
        SOLVER_CUDA = 512       //will be open sourced during Game Developers Conference 2009. Much faster.
};

struct btContactSolverInfoData
{
        

        btScalar        m_tau;
        btScalar        m_damping;//global non-contact constraint damping, can be locally overridden by constraints during 'getInfo2'.
        btScalar        m_friction;
        btScalar        m_timeStep;
        btScalar        m_restitution;
        int             m_numIterations;
        btScalar        m_maxErrorReduction;
        btScalar        m_sor;
        btScalar        m_erp;//used as Baumgarte factor
        btScalar        m_erp2;//used in Split Impulse
        btScalar        m_globalCfm;//constraint force mixing
        int                     m_splitImpulse;
        btScalar        m_splitImpulsePenetrationThreshold;
        btScalar        m_linearSlop;
        btScalar        m_warmstartingFactor;

        int                     m_solverMode;
        int     m_restingContactRestitutionThreshold;
        int                     m_minimumSolverBatchSize;


};

struct btContactSolverInfo : public btContactSolverInfoData
{

        

        inline btContactSolverInfo()
        {
                m_tau = btScalar(0.6);
                m_damping = btScalar(1.0);
                m_friction = btScalar(0.3);
                m_restitution = btScalar(0.);
                m_maxErrorReduction = btScalar(20.);
                m_numIterations = 10;
                m_erp = btScalar(0.2);
                m_erp2 = btScalar(0.1);
                m_globalCfm = btScalar(0.);
                m_sor = btScalar(1.);
                m_splitImpulse = false;
                m_splitImpulsePenetrationThreshold = -0.02f;
                m_linearSlop = btScalar(0.0);
                m_warmstartingFactor=btScalar(0.85);
                m_solverMode = SOLVER_USE_WARMSTARTING | SOLVER_SIMD;// | SOLVER_RANDMIZE_ORDER;
                m_restingContactRestitutionThreshold = 2;//resting contact lifetime threshold to disable restitution
                m_minimumSolverBatchSize = 128; //try to combine islands until the amount of constraints reaches this limit
        }
};

#endif //BT_CONTACT_SOLVER_INFO