urho3d/Source/ThirdParty/Bullet/src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp

/*
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.
*/

// Modified by Lasse Oorni for Urho3D

//#define COMPUTE_IMPULSE_DENOM 1
//#define BT_ADDITIONAL_DEBUG

//It is not necessary (redundant) to refresh contact manifolds, this refresh has been moved to the collision algorithms.

#include "btSequentialImpulseConstraintSolver.h"
#include "BulletCollision/NarrowPhaseCollision/btPersistentManifold.h"

#include "LinearMath/btIDebugDraw.h"
#include "LinearMath/btCpuFeatureUtility.h"

//#include "btJacobianEntry.h"
#include "LinearMath/btMinMax.h"
#include "BulletDynamics/ConstraintSolver/btTypedConstraint.h"
#include <new>
#include "LinearMath/btStackAlloc.h"
#include "LinearMath/btQuickprof.h"
//#include "btSolverBody.h"
//#include "btSolverConstraint.h"
#include "LinearMath/btAlignedObjectArray.h"
#include <string.h> //for memset

int		gNumSplitImpulseRecoveries = 0;

#include "BulletDynamics/Dynamics/btRigidBody.h"

//#define VERBOSE_RESIDUAL_PRINTF 1
///This is the scalar reference implementation of solving a single constraint row, the innerloop of the Projected Gauss Seidel/Sequential Impulse constraint solver
///Below are optional SSE2 and SSE4/FMA3 versions. We assume most hardware has SSE2. For SSE4/FMA3 we perform a CPU feature check.
static btSimdScalar gResolveSingleConstraintRowGeneric_scalar_reference(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
	btScalar deltaImpulse = c.m_rhs - btScalar(c.m_appliedImpulse)*c.m_cfm;
	const btScalar deltaVel1Dotn = c.m_contactNormal1.dot(body1.internalGetDeltaLinearVelocity()) + c.m_relpos1CrossNormal.dot(body1.internalGetDeltaAngularVelocity());
	const btScalar deltaVel2Dotn = c.m_contactNormal2.dot(body2.internalGetDeltaLinearVelocity()) + c.m_relpos2CrossNormal.dot(body2.internalGetDeltaAngularVelocity());

	//	const btScalar delta_rel_vel	=	deltaVel1Dotn-deltaVel2Dotn;
	deltaImpulse -= deltaVel1Dotn*c.m_jacDiagABInv;
	deltaImpulse -= deltaVel2Dotn*c.m_jacDiagABInv;

	const btScalar sum = btScalar(c.m_appliedImpulse) + deltaImpulse;
	if (sum < c.m_lowerLimit)
	{
		deltaImpulse = c.m_lowerLimit - c.m_appliedImpulse;
		c.m_appliedImpulse = c.m_lowerLimit;
	}
	else if (sum > c.m_upperLimit)
	{
		deltaImpulse = c.m_upperLimit - c.m_appliedImpulse;
		c.m_appliedImpulse = c.m_upperLimit;
	}
	else
	{
		c.m_appliedImpulse = sum;
	}

	body1.internalApplyImpulse(c.m_contactNormal1*body1.internalGetInvMass(), c.m_angularComponentA, deltaImpulse);
	body2.internalApplyImpulse(c.m_contactNormal2*body2.internalGetInvMass(), c.m_angularComponentB, deltaImpulse);

	return deltaImpulse;
}


static btSimdScalar gResolveSingleConstraintRowLowerLimit_scalar_reference(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
	btScalar deltaImpulse = c.m_rhs - btScalar(c.m_appliedImpulse)*c.m_cfm;
	const btScalar deltaVel1Dotn = c.m_contactNormal1.dot(body1.internalGetDeltaLinearVelocity()) + c.m_relpos1CrossNormal.dot(body1.internalGetDeltaAngularVelocity());
	const btScalar deltaVel2Dotn = c.m_contactNormal2.dot(body2.internalGetDeltaLinearVelocity()) + c.m_relpos2CrossNormal.dot(body2.internalGetDeltaAngularVelocity());

	deltaImpulse -= deltaVel1Dotn*c.m_jacDiagABInv;
	deltaImpulse -= deltaVel2Dotn*c.m_jacDiagABInv;
	const btScalar sum = btScalar(c.m_appliedImpulse) + deltaImpulse;
	if (sum < c.m_lowerLimit)
	{
		deltaImpulse = c.m_lowerLimit - c.m_appliedImpulse;
		c.m_appliedImpulse = c.m_lowerLimit;
	}
	else
	{
		c.m_appliedImpulse = sum;
	}
	body1.internalApplyImpulse(c.m_contactNormal1*body1.internalGetInvMass(), c.m_angularComponentA, deltaImpulse);
	body2.internalApplyImpulse(c.m_contactNormal2*body2.internalGetInvMass(), c.m_angularComponentB, deltaImpulse);

	return deltaImpulse;
}



#ifdef USE_SIMD
#include <emmintrin.h>


#define btVecSplat(x, e) _mm_shuffle_ps(x, x, _MM_SHUFFLE(e,e,e,e))
static inline __m128 btSimdDot3( __m128 vec0, __m128 vec1 )
{
	__m128 result = _mm_mul_ps( vec0, vec1);
	return _mm_add_ps( btVecSplat( result, 0 ), _mm_add_ps( btVecSplat( result, 1 ), btVecSplat( result, 2 ) ) );
}

#if defined (BT_ALLOW_SSE4)
#include <intrin.h>

#define USE_FMA					1
#define USE_FMA3_INSTEAD_FMA4	1
#define USE_SSE4_DOT			1

#define SSE4_DP(a, b)			_mm_dp_ps(a, b, 0x7f)
#define SSE4_DP_FP(a, b)		_mm_cvtss_f32(_mm_dp_ps(a, b, 0x7f))

#if USE_SSE4_DOT
#define DOT_PRODUCT(a, b)		SSE4_DP(a, b)
#else
#define DOT_PRODUCT(a, b)		btSimdDot3(a, b)
#endif

#if USE_FMA
#if USE_FMA3_INSTEAD_FMA4
// a*b + c
#define FMADD(a, b, c)		_mm_fmadd_ps(a, b, c)
// -(a*b) + c
#define FMNADD(a, b, c)		_mm_fnmadd_ps(a, b, c)
#else // USE_FMA3
// a*b + c
#define FMADD(a, b, c)		_mm_macc_ps(a, b, c)
// -(a*b) + c
#define FMNADD(a, b, c)		_mm_nmacc_ps(a, b, c)
#endif
#else // USE_FMA
// c + a*b
#define FMADD(a, b, c)		_mm_add_ps(c, _mm_mul_ps(a, b))
// c - a*b
#define FMNADD(a, b, c)		_mm_sub_ps(c, _mm_mul_ps(a, b))
#endif
#endif

// Project Gauss Seidel or the equivalent Sequential Impulse
static btSimdScalar gResolveSingleConstraintRowGeneric_sse2(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
	__m128 cpAppliedImp = _mm_set1_ps(c.m_appliedImpulse);
	__m128	lowerLimit1 = _mm_set1_ps(c.m_lowerLimit);
	__m128	upperLimit1 = _mm_set1_ps(c.m_upperLimit);
	btSimdScalar deltaImpulse = _mm_sub_ps(_mm_set1_ps(c.m_rhs), _mm_mul_ps(_mm_set1_ps(c.m_appliedImpulse), _mm_set1_ps(c.m_cfm)));
	__m128 deltaVel1Dotn = _mm_add_ps(btSimdDot3(c.m_contactNormal1.mVec128, body1.internalGetDeltaLinearVelocity().mVec128), btSimdDot3(c.m_relpos1CrossNormal.mVec128, body1.internalGetDeltaAngularVelocity().mVec128));
	__m128 deltaVel2Dotn = _mm_add_ps(btSimdDot3(c.m_contactNormal2.mVec128, body2.internalGetDeltaLinearVelocity().mVec128), btSimdDot3(c.m_relpos2CrossNormal.mVec128, body2.internalGetDeltaAngularVelocity().mVec128));
	deltaImpulse = _mm_sub_ps(deltaImpulse, _mm_mul_ps(deltaVel1Dotn, _mm_set1_ps(c.m_jacDiagABInv)));
	deltaImpulse = _mm_sub_ps(deltaImpulse, _mm_mul_ps(deltaVel2Dotn, _mm_set1_ps(c.m_jacDiagABInv)));
	btSimdScalar sum = _mm_add_ps(cpAppliedImp, deltaImpulse);
	btSimdScalar resultLowerLess, resultUpperLess;
	resultLowerLess = _mm_cmplt_ps(sum, lowerLimit1);
	resultUpperLess = _mm_cmplt_ps(sum, upperLimit1);
	__m128 lowMinApplied = _mm_sub_ps(lowerLimit1, cpAppliedImp);
	deltaImpulse = _mm_or_ps(_mm_and_ps(resultLowerLess, lowMinApplied), _mm_andnot_ps(resultLowerLess, deltaImpulse));
	c.m_appliedImpulse = _mm_or_ps(_mm_and_ps(resultLowerLess, lowerLimit1), _mm_andnot_ps(resultLowerLess, sum));
	__m128 upperMinApplied = _mm_sub_ps(upperLimit1, cpAppliedImp);
	deltaImpulse = _mm_or_ps(_mm_and_ps(resultUpperLess, deltaImpulse), _mm_andnot_ps(resultUpperLess, upperMinApplied));
	c.m_appliedImpulse = _mm_or_ps(_mm_and_ps(resultUpperLess, c.m_appliedImpulse), _mm_andnot_ps(resultUpperLess, upperLimit1));
	__m128	linearComponentA = _mm_mul_ps(c.m_contactNormal1.mVec128, body1.internalGetInvMass().mVec128);
	__m128	linearComponentB = _mm_mul_ps((c.m_contactNormal2).mVec128, body2.internalGetInvMass().mVec128);
	__m128 impulseMagnitude = deltaImpulse;
	body1.internalGetDeltaLinearVelocity().mVec128 = _mm_add_ps(body1.internalGetDeltaLinearVelocity().mVec128, _mm_mul_ps(linearComponentA, impulseMagnitude));
	body1.internalGetDeltaAngularVelocity().mVec128 = _mm_add_ps(body1.internalGetDeltaAngularVelocity().mVec128, _mm_mul_ps(c.m_angularComponentA.mVec128, impulseMagnitude));
	body2.internalGetDeltaLinearVelocity().mVec128 = _mm_add_ps(body2.internalGetDeltaLinearVelocity().mVec128, _mm_mul_ps(linearComponentB, impulseMagnitude));
	body2.internalGetDeltaAngularVelocity().mVec128 = _mm_add_ps(body2.internalGetDeltaAngularVelocity().mVec128, _mm_mul_ps(c.m_angularComponentB.mVec128, impulseMagnitude));
	return deltaImpulse;
}


// Enhanced version of gResolveSingleConstraintRowGeneric_sse2 with SSE4.1 and FMA3
static btSimdScalar gResolveSingleConstraintRowGeneric_sse4_1_fma3(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
#if defined (BT_ALLOW_SSE4)
	__m128 tmp					= _mm_set_ps1(c.m_jacDiagABInv);
	__m128 deltaImpulse			= _mm_set_ps1(c.m_rhs - btScalar(c.m_appliedImpulse)*c.m_cfm);
	const __m128 lowerLimit		= _mm_set_ps1(c.m_lowerLimit);
	const __m128 upperLimit		= _mm_set_ps1(c.m_upperLimit);
	const __m128 deltaVel1Dotn	= _mm_add_ps(DOT_PRODUCT(c.m_contactNormal1.mVec128, body1.internalGetDeltaLinearVelocity().mVec128), DOT_PRODUCT(c.m_relpos1CrossNormal.mVec128, body1.internalGetDeltaAngularVelocity().mVec128));
	const __m128 deltaVel2Dotn	= _mm_add_ps(DOT_PRODUCT(c.m_contactNormal2.mVec128, body2.internalGetDeltaLinearVelocity().mVec128), DOT_PRODUCT(c.m_relpos2CrossNormal.mVec128, body2.internalGetDeltaAngularVelocity().mVec128));
	deltaImpulse				= FMNADD(deltaVel1Dotn, tmp, deltaImpulse);
	deltaImpulse				= FMNADD(deltaVel2Dotn, tmp, deltaImpulse);
	tmp							= _mm_add_ps(c.m_appliedImpulse, deltaImpulse); // sum
	const __m128 maskLower		= _mm_cmpgt_ps(tmp, lowerLimit);
	const __m128 maskUpper		= _mm_cmpgt_ps(upperLimit, tmp);
	deltaImpulse				= _mm_blendv_ps(_mm_sub_ps(lowerLimit, c.m_appliedImpulse), _mm_blendv_ps(_mm_sub_ps(upperLimit, c.m_appliedImpulse), deltaImpulse, maskUpper), maskLower);
	c.m_appliedImpulse			= _mm_blendv_ps(lowerLimit, _mm_blendv_ps(upperLimit, tmp, maskUpper), maskLower);
	body1.internalGetDeltaLinearVelocity().mVec128	= FMADD(_mm_mul_ps(c.m_contactNormal1.mVec128, body1.internalGetInvMass().mVec128), deltaImpulse, body1.internalGetDeltaLinearVelocity().mVec128);
	body1.internalGetDeltaAngularVelocity().mVec128 = FMADD(c.m_angularComponentA.mVec128, deltaImpulse, body1.internalGetDeltaAngularVelocity().mVec128);
	body2.internalGetDeltaLinearVelocity().mVec128	= FMADD(_mm_mul_ps(c.m_contactNormal2.mVec128, body2.internalGetInvMass().mVec128), deltaImpulse, body2.internalGetDeltaLinearVelocity().mVec128);
	body2.internalGetDeltaAngularVelocity().mVec128 = FMADD(c.m_angularComponentB.mVec128, deltaImpulse, body2.internalGetDeltaAngularVelocity().mVec128);
	return deltaImpulse;
#else
	return gResolveSingleConstraintRowGeneric_sse2(body1,body2,c);
#endif
}



static btSimdScalar gResolveSingleConstraintRowLowerLimit_sse2(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
	__m128 cpAppliedImp = _mm_set1_ps(c.m_appliedImpulse);
	__m128	lowerLimit1 = _mm_set1_ps(c.m_lowerLimit);
	__m128	upperLimit1 = _mm_set1_ps(c.m_upperLimit);
	btSimdScalar deltaImpulse = _mm_sub_ps(_mm_set1_ps(c.m_rhs), _mm_mul_ps(_mm_set1_ps(c.m_appliedImpulse), _mm_set1_ps(c.m_cfm)));
	__m128 deltaVel1Dotn = _mm_add_ps(btSimdDot3(c.m_contactNormal1.mVec128, body1.internalGetDeltaLinearVelocity().mVec128), btSimdDot3(c.m_relpos1CrossNormal.mVec128, body1.internalGetDeltaAngularVelocity().mVec128));
	__m128 deltaVel2Dotn = _mm_add_ps(btSimdDot3(c.m_contactNormal2.mVec128, body2.internalGetDeltaLinearVelocity().mVec128), btSimdDot3(c.m_relpos2CrossNormal.mVec128, body2.internalGetDeltaAngularVelocity().mVec128));
	deltaImpulse = _mm_sub_ps(deltaImpulse, _mm_mul_ps(deltaVel1Dotn, _mm_set1_ps(c.m_jacDiagABInv)));
	deltaImpulse = _mm_sub_ps(deltaImpulse, _mm_mul_ps(deltaVel2Dotn, _mm_set1_ps(c.m_jacDiagABInv)));
	btSimdScalar sum = _mm_add_ps(cpAppliedImp, deltaImpulse);
	btSimdScalar resultLowerLess, resultUpperLess;
	resultLowerLess = _mm_cmplt_ps(sum, lowerLimit1);
	resultUpperLess = _mm_cmplt_ps(sum, upperLimit1);
	__m128 lowMinApplied = _mm_sub_ps(lowerLimit1, cpAppliedImp);
	deltaImpulse = _mm_or_ps(_mm_and_ps(resultLowerLess, lowMinApplied), _mm_andnot_ps(resultLowerLess, deltaImpulse));
	c.m_appliedImpulse = _mm_or_ps(_mm_and_ps(resultLowerLess, lowerLimit1), _mm_andnot_ps(resultLowerLess, sum));
	__m128	linearComponentA = _mm_mul_ps(c.m_contactNormal1.mVec128, body1.internalGetInvMass().mVec128);
	__m128	linearComponentB = _mm_mul_ps(c.m_contactNormal2.mVec128, body2.internalGetInvMass().mVec128);
	__m128 impulseMagnitude = deltaImpulse;
	body1.internalGetDeltaLinearVelocity().mVec128 = _mm_add_ps(body1.internalGetDeltaLinearVelocity().mVec128, _mm_mul_ps(linearComponentA, impulseMagnitude));
	body1.internalGetDeltaAngularVelocity().mVec128 = _mm_add_ps(body1.internalGetDeltaAngularVelocity().mVec128, _mm_mul_ps(c.m_angularComponentA.mVec128, impulseMagnitude));
	body2.internalGetDeltaLinearVelocity().mVec128 = _mm_add_ps(body2.internalGetDeltaLinearVelocity().mVec128, _mm_mul_ps(linearComponentB, impulseMagnitude));
	body2.internalGetDeltaAngularVelocity().mVec128 = _mm_add_ps(body2.internalGetDeltaAngularVelocity().mVec128, _mm_mul_ps(c.m_angularComponentB.mVec128, impulseMagnitude));
	return deltaImpulse;
}


// Enhanced version of gResolveSingleConstraintRowGeneric_sse2 with SSE4.1 and FMA3
static btSimdScalar gResolveSingleConstraintRowLowerLimit_sse4_1_fma3(btSolverBody& body1, btSolverBody& body2, const btSolverConstraint& c)
{
#ifdef BT_ALLOW_SSE4
	__m128 tmp					= _mm_set_ps1(c.m_jacDiagABInv);
	__m128 deltaImpulse			= _mm_set_ps1(c.m_rhs - btScalar(c.m_appliedImpulse)*c.m_cfm);
	const __m128 lowerLimit		= _mm_set_ps1(c.m_lowerLimit);
	const __m128 deltaVel1Dotn	= _mm_add_ps(DOT_PRODUCT(c.m_contactNormal1.mVec128, body1.internalGetDeltaLinearVelocity().mVec128), DOT_PRODUCT(c.m_relpos1CrossNormal.mVec128, body1.internalGetDeltaAngularVelocity().mVec128));
	const __m128 deltaVel2Dotn	= _mm_add_ps(DOT_PRODUCT(c.m_contactNormal2.mVec128, body2.internalGetDeltaLinearVelocity().mVec128), DOT_PRODUCT(c.m_relpos2CrossNormal.mVec128, body2.internalGetDeltaAngularVelocity().mVec128));
	deltaImpulse				= FMNADD(deltaVel1Dotn, tmp, deltaImpulse);
	deltaImpulse				= FMNADD(deltaVel2Dotn, tmp, deltaImpulse);
	tmp							= _mm_add_ps(c.m_appliedImpulse, deltaImpulse);
	const __m128 mask			= _mm_cmpgt_ps(tmp, lowerLimit);
	deltaImpulse				= _mm_blendv_ps(_mm_sub_ps(lowerLimit, c.m_appliedImpulse), deltaImpulse, mask);
	c.m_appliedImpulse			= _mm_blendv_ps(lowerLimit, tmp, mask);
	body1.internalGetDeltaLinearVelocity().mVec128	= FMADD(_mm_mul_ps(c.m_contactNormal1.mVec128, body1.internalGetInvMass().mVec128), deltaImpulse, body1.internalGetDeltaLinearVelocity().mVec128);
	body1.internalGetDeltaAngularVelocity().mVec128 = FMADD(c.m_angularComponentA.mVec128, deltaImpulse, body1.internalGetDeltaAngularVelocity().mVec128);
	body2.internalGetDeltaLinearVelocity().mVec128	= FMADD(_mm_mul_ps(c.m_contactNormal2.mVec128, body2.internalGetInvMass().mVec128), deltaImpulse, body2.internalGetDeltaLinearVelocity().mVec128);
	body2.internalGetDeltaAngularVelocity().mVec128 = FMADD(c.m_angularComponentB.mVec128, deltaImpulse, body2.internalGetDeltaAngularVelocity().mVec128);
	return deltaImpulse;
#else
	return gResolveSingleConstraintRowLowerLimit_sse2(body1,body2,c);
#endif //BT_ALLOW_SSE4
}


#endif //USE_SIMD



btSimdScalar btSequentialImpulseConstraintSolver::resolveSingleConstraintRowGenericSIMD(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
#ifdef USE_SIMD
	return m_resolveSingleConstraintRowGeneric(body1, body2, c);
#else
	return resolveSingleConstraintRowGeneric(body1,body2,c);
#endif
}

// Project Gauss Seidel or the equivalent Sequential Impulse
btSimdScalar btSequentialImpulseConstraintSolver::resolveSingleConstraintRowGeneric(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
	return gResolveSingleConstraintRowGeneric_scalar_reference(body1, body2, c);
}

btSimdScalar btSequentialImpulseConstraintSolver::resolveSingleConstraintRowLowerLimitSIMD(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
#ifdef USE_SIMD
	return m_resolveSingleConstraintRowLowerLimit(body1, body2, c);
#else
	return resolveSingleConstraintRowLowerLimit(body1,body2,c);
#endif
}


btSimdScalar btSequentialImpulseConstraintSolver::resolveSingleConstraintRowLowerLimit(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
	return gResolveSingleConstraintRowLowerLimit_scalar_reference(body1,body2,c);
}


btScalar btSequentialImpulseConstraintSolver::resolveSplitPenetrationImpulseCacheFriendly(
        btSolverBody& body1,
        btSolverBody& body2,
        const btSolverConstraint& c)
{
	btScalar deltaImpulse = 0.f;

		if (c.m_rhsPenetration)
        {
			gNumSplitImpulseRecoveries++;
			deltaImpulse = c.m_rhsPenetration-btScalar(c.m_appliedPushImpulse)*c.m_cfm;
			const btScalar deltaVel1Dotn	=	c.m_contactNormal1.dot(body1.internalGetPushVelocity()) 	+ c.m_relpos1CrossNormal.dot(body1.internalGetTurnVelocity());
			const btScalar deltaVel2Dotn	=	c.m_contactNormal2.dot(body2.internalGetPushVelocity())		+ c.m_relpos2CrossNormal.dot(body2.internalGetTurnVelocity());

			deltaImpulse	-=	deltaVel1Dotn*c.m_jacDiagABInv;
			deltaImpulse	-=	deltaVel2Dotn*c.m_jacDiagABInv;
			const btScalar sum = btScalar(c.m_appliedPushImpulse) + deltaImpulse;
			if (sum < c.m_lowerLimit)
			{
				deltaImpulse = c.m_lowerLimit-c.m_appliedPushImpulse;
				c.m_appliedPushImpulse = c.m_lowerLimit;
			}
			else
			{
				c.m_appliedPushImpulse = sum;
			}
			body1.internalApplyPushImpulse(c.m_contactNormal1*body1.internalGetInvMass(),c.m_angularComponentA,deltaImpulse);
			body2.internalApplyPushImpulse(c.m_contactNormal2*body2.internalGetInvMass(),c.m_angularComponentB,deltaImpulse);
        }
		return deltaImpulse;
}

btSimdScalar btSequentialImpulseConstraintSolver::resolveSplitPenetrationSIMD(btSolverBody& body1,btSolverBody& body2,const btSolverConstraint& c)
{
#ifdef USE_SIMD
	if (!c.m_rhsPenetration)
		return 0.f;

	gNumSplitImpulseRecoveries++;

	__m128 cpAppliedImp = _mm_set1_ps(c.m_appliedPushImpulse);
	__m128	lowerLimit1 = _mm_set1_ps(c.m_lowerLimit);
	__m128	upperLimit1 = _mm_set1_ps(c.m_upperLimit);
	__m128 deltaImpulse = _mm_sub_ps(_mm_set1_ps(c.m_rhsPenetration), _mm_mul_ps(_mm_set1_ps(c.m_appliedPushImpulse),_mm_set1_ps(c.m_cfm)));
	__m128 deltaVel1Dotn	=	_mm_add_ps(btSimdDot3(c.m_contactNormal1.mVec128,body1.internalGetPushVelocity().mVec128), btSimdDot3(c.m_relpos1CrossNormal.mVec128,body1.internalGetTurnVelocity().mVec128));
	__m128 deltaVel2Dotn	=	_mm_add_ps(btSimdDot3(c.m_contactNormal2.mVec128,body2.internalGetPushVelocity().mVec128), btSimdDot3(c.m_relpos2CrossNormal.mVec128,body2.internalGetTurnVelocity().mVec128));
	deltaImpulse	=	_mm_sub_ps(deltaImpulse,_mm_mul_ps(deltaVel1Dotn,_mm_set1_ps(c.m_jacDiagABInv)));
	deltaImpulse	=	_mm_sub_ps(deltaImpulse,_mm_mul_ps(deltaVel2Dotn,_mm_set1_ps(c.m_jacDiagABInv)));
	btSimdScalar sum = _mm_add_ps(cpAppliedImp,deltaImpulse);
	btSimdScalar resultLowerLess,resultUpperLess;
	resultLowerLess = _mm_cmplt_ps(sum,lowerLimit1);
	resultUpperLess = _mm_cmplt_ps(sum,upperLimit1);
	__m128 lowMinApplied = _mm_sub_ps(lowerLimit1,cpAppliedImp);
	deltaImpulse = _mm_or_ps( _mm_and_ps(resultLowerLess, lowMinApplied), _mm_andnot_ps(resultLowerLess, deltaImpulse) );
	c.m_appliedPushImpulse = _mm_or_ps( _mm_and_ps(resultLowerLess, lowerLimit1), _mm_andnot_ps(resultLowerLess, sum) );
	__m128	linearComponentA = _mm_mul_ps(c.m_contactNormal1.mVec128,body1.internalGetInvMass().mVec128);
	__m128	linearComponentB = _mm_mul_ps(c.m_contactNormal2.mVec128,body2.internalGetInvMass().mVec128);
	__m128 impulseMagnitude = deltaImpulse;
	body1.internalGetPushVelocity().mVec128 = _mm_add_ps(body1.internalGetPushVelocity().mVec128,_mm_mul_ps(linearComponentA,impulseMagnitude));
	body1.internalGetTurnVelocity().mVec128 = _mm_add_ps(body1.internalGetTurnVelocity().mVec128 ,_mm_mul_ps(c.m_angularComponentA.mVec128,impulseMagnitude));
	body2.internalGetPushVelocity().mVec128 = _mm_add_ps(body2.internalGetPushVelocity().mVec128,_mm_mul_ps(linearComponentB,impulseMagnitude));
	body2.internalGetTurnVelocity().mVec128 = _mm_add_ps(body2.internalGetTurnVelocity().mVec128 ,_mm_mul_ps(c.m_angularComponentB.mVec128,impulseMagnitude));
	return deltaImpulse;
#else
	return resolveSplitPenetrationImpulseCacheFriendly(body1,body2,c);
#endif
}


 btSequentialImpulseConstraintSolver::btSequentialImpulseConstraintSolver()
	 : m_resolveSingleConstraintRowGeneric(gResolveSingleConstraintRowGeneric_scalar_reference),
	 m_resolveSingleConstraintRowLowerLimit(gResolveSingleConstraintRowLowerLimit_scalar_reference),
	 m_btSeed2(0)
 {

#ifdef USE_SIMD
	 m_resolveSingleConstraintRowGeneric = gResolveSingleConstraintRowGeneric_sse2;
	 m_resolveSingleConstraintRowLowerLimit=gResolveSingleConstraintRowLowerLimit_sse2;
#endif //USE_SIMD

#ifdef BT_ALLOW_SSE4
	 int cpuFeatures = btCpuFeatureUtility::getCpuFeatures();
	 if ((cpuFeatures & btCpuFeatureUtility::CPU_FEATURE_FMA3) && (cpuFeatures & btCpuFeatureUtility::CPU_FEATURE_SSE4_1))
	 {
		m_resolveSingleConstraintRowGeneric = gResolveSingleConstraintRowGeneric_sse4_1_fma3;
		m_resolveSingleConstraintRowLowerLimit = gResolveSingleConstraintRowLowerLimit_sse4_1_fma3;
	 }
#endif//BT_ALLOW_SSE4

 }

 btSequentialImpulseConstraintSolver::~btSequentialImpulseConstraintSolver()
 {
 }

 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getScalarConstraintRowSolverGeneric()
 {
	 return gResolveSingleConstraintRowGeneric_scalar_reference;
 }

 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getScalarConstraintRowSolverLowerLimit()
 {
	 return gResolveSingleConstraintRowLowerLimit_scalar_reference;
 }


#ifdef USE_SIMD
 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getSSE2ConstraintRowSolverGeneric()
 {
	 return gResolveSingleConstraintRowGeneric_sse2;
 }
 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getSSE2ConstraintRowSolverLowerLimit()
 {
	 return gResolveSingleConstraintRowLowerLimit_sse2;
 }
#ifdef BT_ALLOW_SSE4
 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getSSE4_1ConstraintRowSolverGeneric()
 {
	 return gResolveSingleConstraintRowGeneric_sse4_1_fma3;
 }
 btSingleConstraintRowSolver	btSequentialImpulseConstraintSolver::getSSE4_1ConstraintRowSolverLowerLimit()
 {
	 return gResolveSingleConstraintRowLowerLimit_sse4_1_fma3;
 }
#endif //BT_ALLOW_SSE4
#endif //USE_SIMD

unsigned long btSequentialImpulseConstraintSolver::btRand2()
{
	m_btSeed2 = (1664525L*m_btSeed2 + 1013904223L) & 0xffffffff;
	return m_btSeed2;
}



//See ODE: adam's all-int straightforward(?) dRandInt (0..n-1)
int btSequentialImpulseConstraintSolver::btRandInt2 (int n)
{
	// seems good; xor-fold and modulus
	const unsigned long un = static_cast<unsigned long>(n);
	unsigned long r = btRand2();

	// note: probably more aggressive than it needs to be -- might be
	//       able to get away without one or two of the innermost branches.
	if (un <= 0x00010000UL) {
		r ^= (r >> 16);
		if (un <= 0x00000100UL) {
			r ^= (r >> 8);
			if (un <= 0x00000010UL) {
				r ^= (r >> 4);
				if (un <= 0x00000004UL) {
					r ^= (r >> 2);
					if (un <= 0x00000002UL) {
						r ^= (r >> 1);
					}
				}
			}
		}
	}

	return (int) (r % un);
}



void	btSequentialImpulseConstraintSolver::initSolverBody(btSolverBody* solverBody, btCollisionObject* collisionObject, btScalar timeStep)
{

	btRigidBody* rb = collisionObject? btRigidBody::upcast(collisionObject) : 0;

	solverBody->internalGetDeltaLinearVelocity().setValue(0.f,0.f,0.f);
	solverBody->internalGetDeltaAngularVelocity().setValue(0.f,0.f,0.f);
	solverBody->internalGetPushVelocity().setValue(0.f,0.f,0.f);
	solverBody->internalGetTurnVelocity().setValue(0.f,0.f,0.f);

	if (rb)
	{
		solverBody->m_worldTransform = rb->getWorldTransform();
		solverBody->internalSetInvMass(btVector3(rb->getInvMass(),rb->getInvMass(),rb->getInvMass())*rb->getLinearFactor());
		solverBody->m_originalBody = rb;
		solverBody->m_angularFactor = rb->getAngularFactor();
		solverBody->m_linearFactor = rb->getLinearFactor();
		solverBody->m_linearVelocity = rb->getLinearVelocity();
		solverBody->m_angularVelocity = rb->getAngularVelocity();
		solverBody->m_externalForceImpulse = rb->getTotalForce()*rb->getInvMass()*timeStep;
		solverBody->m_externalTorqueImpulse = rb->getTotalTorque()*rb->getInvInertiaTensorWorld()*timeStep ;

	} else
	{
		solverBody->m_worldTransform.setIdentity();
		solverBody->internalSetInvMass(btVector3(0,0,0));
		solverBody->m_originalBody = 0;
		solverBody->m_angularFactor.setValue(1,1,1);
		solverBody->m_linearFactor.setValue(1,1,1);
		solverBody->m_linearVelocity.setValue(0,0,0);
		solverBody->m_angularVelocity.setValue(0,0,0);
		solverBody->m_externalForceImpulse.setValue(0,0,0);
		solverBody->m_externalTorqueImpulse.setValue(0,0,0);
	}


}






btScalar btSequentialImpulseConstraintSolver::restitutionCurve(btScalar rel_vel, btScalar restitution)
{
	btScalar rest = restitution * -rel_vel;
	return rest;
}



void	btSequentialImpulseConstraintSolver::applyAnisotropicFriction(btCollisionObject* colObj,btVector3& frictionDirection, int frictionMode)
{


	if (colObj && colObj->hasAnisotropicFriction(frictionMode))
	{
		// transform to local coordinates
		btVector3 loc_lateral = frictionDirection * colObj->getWorldTransform().getBasis();
		const btVector3& friction_scaling = colObj->getAnisotropicFriction();
		//apply anisotropic friction
		loc_lateral *= friction_scaling;
		// ... and transform it back to global coordinates
		frictionDirection = colObj->getWorldTransform().getBasis() * loc_lateral;
	}

}




void btSequentialImpulseConstraintSolver::setupFrictionConstraint(btSolverConstraint& solverConstraint, const btVector3& normalAxis,int  solverBodyIdA,int solverBodyIdB,btManifoldPoint& cp,const btVector3& rel_pos1,const btVector3& rel_pos2,btCollisionObject* colObj0,btCollisionObject* colObj1, btScalar relaxation, btScalar desiredVelocity, btScalar cfmSlip)
{


	btSolverBody& solverBodyA = m_tmpSolverBodyPool[solverBodyIdA];
	btSolverBody& solverBodyB = m_tmpSolverBodyPool[solverBodyIdB];

	btRigidBody* body0 = m_tmpSolverBodyPool[solverBodyIdA].m_originalBody;
	btRigidBody* body1 = m_tmpSolverBodyPool[solverBodyIdB].m_originalBody;

	solverConstraint.m_solverBodyIdA = solverBodyIdA;
	solverConstraint.m_solverBodyIdB = solverBodyIdB;

	solverConstraint.m_friction = cp.m_combinedFriction;
	solverConstraint.m_originalContactPoint = 0;

	solverConstraint.m_appliedImpulse = 0.f;
	solverConstraint.m_appliedPushImpulse = 0.f;

	if (body0)
	{
		solverConstraint.m_contactNormal1 = normalAxis;
		btVector3 ftorqueAxis1 = rel_pos1.cross(solverConstraint.m_contactNormal1);
		solverConstraint.m_relpos1CrossNormal = ftorqueAxis1;
		solverConstraint.m_angularComponentA = body0->getInvInertiaTensorWorld()*ftorqueAxis1*body0->getAngularFactor();
	}else
	{
		solverConstraint.m_contactNormal1.setZero();
		solverConstraint.m_relpos1CrossNormal.setZero();
		solverConstraint.m_angularComponentA .setZero();
	}

	if (body1)
	{
		solverConstraint.m_contactNormal2 = -normalAxis;
		btVector3 ftorqueAxis1 = rel_pos2.cross(solverConstraint.m_contactNormal2);
		solverConstraint.m_relpos2CrossNormal = ftorqueAxis1;
		solverConstraint.m_angularComponentB = body1->getInvInertiaTensorWorld()*ftorqueAxis1*body1->getAngularFactor();
	} else
	{
		solverConstraint.m_contactNormal2.setZero();
		solverConstraint.m_relpos2CrossNormal.setZero();
		solverConstraint.m_angularComponentB.setZero();
	}

	{
		btVector3 vec;
		btScalar denom0 = 0.f;
		btScalar denom1 = 0.f;
		if (body0)
		{
			vec = ( solverConstraint.m_angularComponentA).cross(rel_pos1);
			denom0 = body0->getInvMass() + normalAxis.dot(vec);
		}
		if (body1)
		{
			vec = ( -solverConstraint.m_angularComponentB).cross(rel_pos2);
			denom1 = body1->getInvMass() + normalAxis.dot(vec);
		}
		btScalar denom = relaxation/(denom0+denom1);
		solverConstraint.m_jacDiagABInv = denom;
	}

	{


		btScalar rel_vel;
		btScalar vel1Dotn = solverConstraint.m_contactNormal1.dot(body0?solverBodyA.m_linearVelocity+solverBodyA.m_externalForceImpulse:btVector3(0,0,0))
			+ solverConstraint.m_relpos1CrossNormal.dot(body0?solverBodyA.m_angularVelocity:btVector3(0,0,0));
		btScalar vel2Dotn = solverConstraint.m_contactNormal2.dot(body1?solverBodyB.m_linearVelocity+solverBodyB.m_externalForceImpulse:btVector3(0,0,0))
			+ solverConstraint.m_relpos2CrossNormal.dot(body1?solverBodyB.m_angularVelocity:btVector3(0,0,0));

		rel_vel = vel1Dotn+vel2Dotn;

//		btScalar positionalError = 0.f;

        // Urho3D: possible friction fix from https://github.com/bulletphysics/bullet3/commit/907ac49892ede3f4a3295f7cbd96759107e5fc0e
		btScalar velocityError =  desiredVelocity - rel_vel;
		btScalar velocityImpulse = velocityError * btScalar(solverConstraint.m_jacDiagABInv);
		solverConstraint.m_rhs = velocityImpulse;
		solverConstraint.m_rhsPenetration = 0.f;
		solverConstraint.m_cfm = cfmSlip;
		solverConstraint.m_lowerLimit = -solverConstraint.m_friction;
		solverConstraint.m_upperLimit = solverConstraint.m_friction;

	}
}

btSolverConstraint&	btSequentialImpulseConstraintSolver::addFrictionConstraint(const btVector3& normalAxis,int solverBodyIdA,int solverBodyIdB,int frictionIndex,btManifoldPoint& cp,const btVector3& rel_pos1,const btVector3& rel_pos2,btCollisionObject* colObj0,btCollisionObject* colObj1, btScalar relaxation, btScalar desiredVelocity, btScalar cfmSlip)
{
	btSolverConstraint& solverConstraint = m_tmpSolverContactFrictionConstraintPool.expandNonInitializing();
	solverConstraint.m_frictionIndex = frictionIndex;
	setupFrictionConstraint(solverConstraint, normalAxis, solverBodyIdA, solverBodyIdB, cp, rel_pos1, rel_pos2,
							colObj0, colObj1, relaxation, desiredVelocity, cfmSlip);
	return solverConstraint;
}


void btSequentialImpulseConstraintSolver::setupTorsionalFrictionConstraint(	btSolverConstraint& solverConstraint, const btVector3& normalAxis1,int solverBodyIdA,int  solverBodyIdB,
									btManifoldPoint& cp,btScalar combinedTorsionalFriction, const btVector3& rel_pos1,const btVector3& rel_pos2,
									btCollisionObject* colObj0,btCollisionObject* colObj1, btScalar relaxation,
									btScalar desiredVelocity, btScalar cfmSlip)

{
	btVector3 normalAxis(0,0,0);


	solverConstraint.m_contactNormal1 = normalAxis;
	solverConstraint.m_contactNormal2 = -normalAxis;
	btSolverBody& solverBodyA = m_tmpSolverBodyPool[solverBodyIdA];
	btSolverBody& solverBodyB = m_tmpSolverBodyPool[solverBodyIdB];

	btRigidBody* body0 = m_tmpSolverBodyPool[solverBodyIdA].m_originalBody;
	btRigidBody* body1 = m_tmpSolverBodyPool[solverBodyIdB].m_originalBody;

	solverConstraint.m_solverBodyIdA = solverBodyIdA;
	solverConstraint.m_solverBodyIdB = solverBodyIdB;

    solverConstraint.m_friction = combinedTorsionalFriction;
    solverConstraint.m_originalContactPoint = 0;

	solverConstraint.m_appliedImpulse = 0.f;
	solverConstraint.m_appliedPushImpulse = 0.f;

	{
		btVector3 ftorqueAxis1 = -normalAxis1;
		solverConstraint.m_relpos1CrossNormal = ftorqueAxis1;
		solverConstraint.m_angularComponentA = body0 ? body0->getInvInertiaTensorWorld()*ftorqueAxis1*body0->getAngularFactor() : btVector3(0,0,0);
	}
	{
		btVector3 ftorqueAxis1 = normalAxis1;
		solverConstraint.m_relpos2CrossNormal = ftorqueAxis1;
		solverConstraint.m_angularComponentB = body1 ? body1->getInvInertiaTensorWorld()*ftorqueAxis1*body1->getAngularFactor() : btVector3(0,0,0);
	}


	{
		btVector3 iMJaA = body0?body0->getInvInertiaTensorWorld()*solverConstraint.m_relpos1CrossNormal:btVector3(0,0,0);
		btVector3 iMJaB = body1?body1->getInvInertiaTensorWorld()*solverConstraint.m_relpos2CrossNormal:btVector3(0,0,0);
		btScalar sum = 0;
		sum += iMJaA.dot(solverConstraint.m_relpos1CrossNormal);
		sum += iMJaB.dot(solverConstraint.m_relpos2CrossNormal);
		solverConstraint.m_jacDiagABInv = btScalar(1.)/sum;
	}

	{


		btScalar rel_vel;
		btScalar vel1Dotn = solverConstraint.m_contactNormal1.dot(body0?solverBodyA.m_linearVelocity+solverBodyA.m_externalForceImpulse:btVector3(0,0,0))
			+ solverConstraint.m_relpos1CrossNormal.dot(body0?solverBodyA.m_angularVelocity:btVector3(0,0,0));
		btScalar vel2Dotn = solverConstraint.m_contactNormal2.dot(body1?solverBodyB.m_linearVelocity+solverBodyB.m_externalForceImpulse:btVector3(0,0,0))
			+ solverConstraint.m_relpos2CrossNormal.dot(body1?solverBodyB.m_angularVelocity:btVector3(0,0,0));

		rel_vel = vel1Dotn+vel2Dotn;

//		btScalar positionalError = 0.f;

        // Urho3D: possible friction fix from https://github.com/bulletphysics/bullet3/commit/907ac49892ede3f4a3295f7cbd96759107e5fc0e
		btScalar velocityError =  desiredVelocity - rel_vel;
		btScalar velocityImpulse = velocityError * btScalar(solverConstraint.m_jacDiagABInv);
		solverConstraint.m_rhs = velocityImpulse;
		solverConstraint.m_cfm = cfmSlip;
		solverConstraint.m_lowerLimit = -solverConstraint.m_friction;
		solverConstraint.m_upperLimit = solverConstraint.m_friction;

	}
}








btSolverConstraint&	btSequentialImpulseConstraintSolver::addTorsionalFrictionConstraint(const btVector3& normalAxis,int solverBodyIdA,int solverBodyIdB,int frictionIndex,btManifoldPoint& cp,btScalar combinedTorsionalFriction, const btVector3& rel_pos1,const btVector3& rel_pos2,btCollisionObject* colObj0,btCollisionObject* colObj1, btScalar relaxation, btScalar desiredVelocity, btScalar cfmSlip)
{
	btSolverConstraint& solverConstraint = m_tmpSolverContactRollingFrictionConstraintPool.expandNonInitializing();
	solverConstraint.m_frictionIndex = frictionIndex;
	setupTorsionalFrictionConstraint(solverConstraint, normalAxis, solverBodyIdA, solverBodyIdB, cp, combinedTorsionalFriction,rel_pos1, rel_pos2,
							colObj0, colObj1, relaxation, desiredVelocity, cfmSlip);
	return solverConstraint;
}


int	btSequentialImpulseConstraintSolver::getOrInitSolverBody(btCollisionObject& body,btScalar timeStep)
{
#if BT_THREADSAFE
    int solverBodyId = -1;
    if ( !body.isStaticOrKinematicObject() )
    {
        // dynamic body
        // Dynamic bodies can only be in one island, so it's safe to write to the companionId
        solverBodyId = body.getCompanionId();
        if ( solverBodyId < 0 )
        {
            if ( btRigidBody* rb = btRigidBody::upcast( &body ) )
            {
                solverBodyId = m_tmpSolverBodyPool.size();
                btSolverBody& solverBody = m_tmpSolverBodyPool.expand();
                initSolverBody( &solverBody, &body, timeStep );
                body.setCompanionId( solverBodyId );
            }
        }
    }
    else if (body.isKinematicObject())
    {
        //
        // NOTE: must test for kinematic before static because some kinematic objects also
        //   identify as "static"
        //
        // Kinematic bodies can be in multiple islands at once, so it is a
        // race condition to write to them, so we use an alternate method
        // to record the solverBodyId
        int uniqueId = body.getWorldArrayIndex();
        const int INVALID_SOLVER_BODY_ID = -1;
        if (uniqueId >= m_kinematicBodyUniqueIdToSolverBodyTable.size())
        {
            m_kinematicBodyUniqueIdToSolverBodyTable.resize(uniqueId + 1, INVALID_SOLVER_BODY_ID);
        }
        solverBodyId = m_kinematicBodyUniqueIdToSolverBodyTable[ uniqueId ];
        // if no table entry yet,
        if ( solverBodyId == INVALID_SOLVER_BODY_ID )
        {
            // create a table entry for this body
            btRigidBody* rb = btRigidBody::upcast( &body );
            solverBodyId = m_tmpSolverBodyPool.size();
            btSolverBody& solverBody = m_tmpSolverBodyPool.expand();
            initSolverBody( &solverBody, &body, timeStep );
            m_kinematicBodyUniqueIdToSolverBodyTable[ uniqueId ] = solverBodyId;
        }
    }
    else
    {
        // all fixed bodies (inf mass) get mapped to a single solver id
        if ( m_fixedBodyId < 0 )
        {
            m_fixedBodyId = m_tmpSolverBodyPool.size();
            btSolverBody& fixedBody = m_tmpSolverBodyPool.expand();
            initSolverBody( &fixedBody, 0, timeStep );
        }
        solverBodyId = m_fixedBodyId;
    }
    btAssert( solverBodyId < m_tmpSolverBodyPool.size() );
	return solverBodyId;
#else // BT_THREADSAFE

    int solverBodyIdA = -1;

	if (body.getCompanionId() >= 0)
	{
		//body has already been converted
		solverBodyIdA = body.getCompanionId();
        btAssert(solverBodyIdA < m_tmpSolverBodyPool.size());
	} else
	{
		btRigidBody* rb = btRigidBody::upcast(&body);
		//convert both active and kinematic objects (for their velocity)
		if (rb && (rb->getInvMass() || rb->isKinematicObject()))
		{
			solverBodyIdA = m_tmpSolverBodyPool.size();
			btSolverBody& solverBody = m_tmpSolverBodyPool.expand();
			initSolverBody(&solverBody,&body,timeStep);
			body.setCompanionId(solverBodyIdA);
		} else
		{

			if (m_fixedBodyId<0)
			{
				m_fixedBodyId = m_tmpSolverBodyPool.size();
				btSolverBody& fixedBody = m_tmpSolverBodyPool.expand();
				initSolverBody(&fixedBody,0,timeStep);
			}
			return m_fixedBodyId;
//			return 0;//assume first one is a fixed solver body
		}
	}

	return solverBodyIdA;
#endif // BT_THREADSAFE

}
#include <stdio.h>


void btSequentialImpulseConstraintSolver::setupContactConstraint(btSolverConstraint& solverConstraint,
																 int solverBodyIdA, int solverBodyIdB,
																 btManifoldPoint& cp, const btContactSolverInfo& infoGlobal,
																 btScalar& relaxation,
																 const btVector3& rel_pos1, const btVector3& rel_pos2)
{

		//	const btVector3& pos1 = cp.getPositionWorldOnA();
		//	const btVector3& pos2 = cp.getPositionWorldOnB();

			btSolverBody* bodyA = &m_tmpSolverBodyPool[solverBodyIdA];
			btSolverBody* bodyB = &m_tmpSolverBodyPool[solverBodyIdB];

			btRigidBody* rb0 = bodyA->m_originalBody;
			btRigidBody* rb1 = bodyB->m_originalBody;

//			btVector3 rel_pos1 = pos1 - colObj0->getWorldTransform().getOrigin();
//			btVector3 rel_pos2 = pos2 - colObj1->getWorldTransform().getOrigin();
			//rel_pos1 = pos1 - bodyA->getWorldTransform().getOrigin();
			//rel_pos2 = pos2 - bodyB->getWorldTransform().getOrigin();

			relaxation = infoGlobal.m_sor;
			btScalar invTimeStep = btScalar(1)/infoGlobal.m_timeStep;

            //cfm = 1 /       ( dt * kp + kd )
            //erp = dt * kp / ( dt * kp + kd )
            
            btScalar cfm = infoGlobal.m_globalCfm;
            btScalar erp = infoGlobal.m_erp2;

            if ((cp.m_contactPointFlags&BT_CONTACT_FLAG_HAS_CONTACT_CFM) || (cp.m_contactPointFlags&BT_CONTACT_FLAG_HAS_CONTACT_ERP))
            {
                if (cp.m_contactPointFlags&BT_CONTACT_FLAG_HAS_CONTACT_CFM)
                    cfm  = cp.m_contactCFM;
                if (cp.m_contactPointFlags&BT_CONTACT_FLAG_HAS_CONTACT_ERP)
                    erp = cp.m_contactERP;                
            } else
            {
                if (cp.m_contactPointFlags & BT_CONTACT_FLAG_CONTACT_STIFFNESS_DAMPING)
                {
                    btScalar denom = ( infoGlobal.m_timeStep * cp.m_combinedContactStiffness1 + cp.m_combinedContactDamping1 );
                    if (denom < SIMD_EPSILON)
                    {
                        denom = SIMD_EPSILON;
                    }
                    cfm = btScalar(1) / denom; 
                    erp = (infoGlobal.m_timeStep * cp.m_combinedContactStiffness1) / denom;
                }
            }
            
            cfm *= invTimeStep;
            

			btVector3 torqueAxis0 = rel_pos1.cross(cp.m_normalWorldOnB);
			solverConstraint.m_angularComponentA = rb0 ? rb0->getInvInertiaTensorWorld()*torqueAxis0*rb0->getAngularFactor() : btVector3(0,0,0);
			btVector3 torqueAxis1 = rel_pos2.cross(cp.m_normalWorldOnB);
			solverConstraint.m_angularComponentB = rb1 ? rb1->getInvInertiaTensorWorld()*-torqueAxis1*rb1->getAngularFactor() : btVector3(0,0,0);

				{
#ifdef COMPUTE_IMPULSE_DENOM
					btScalar denom0 = rb0->computeImpulseDenominator(pos1,cp.m_normalWorldOnB);
					btScalar denom1 = rb1->computeImpulseDenominator(pos2,cp.m_normalWorldOnB);
#else
					btVector3 vec;
					btScalar denom0 = 0.f;
					btScalar denom1 = 0.f;
					if (rb0)
					{
						vec = ( solverConstraint.m_angularComponentA).cross(rel_pos1);
						denom0 = rb0->getInvMass() + cp.m_normalWorldOnB.dot(vec);
					}
					if (rb1)
					{
						vec = ( -solverConstraint.m_angularComponentB).cross(rel_pos2);
						denom1 = rb1->getInvMass() + cp.m_normalWorldOnB.dot(vec);
					}
#endif //COMPUTE_IMPULSE_DENOM

					btScalar denom = relaxation/(denom0+denom1+cfm);
					solverConstraint.m_jacDiagABInv = denom;
				}

				if (rb0)
				{
					solverConstraint.m_contactNormal1 = cp.m_normalWorldOnB;
					solverConstraint.m_relpos1CrossNormal = torqueAxis0;
				} else
				{
					solverConstraint.m_contactNormal1.setZero();
					solverConstraint.m_relpos1CrossNormal.setZero();
				}
				if (rb1)
				{
					solverConstraint.m_contactNormal2 = -cp.m_normalWorldOnB;
					solverConstraint.m_relpos2CrossNormal = -torqueAxis1;
				}else
				{
					solverConstraint.m_contactNormal2.setZero();
					solverConstraint.m_relpos2CrossNormal.setZero();
				}

				btScalar restitution = 0.f;
				btScalar penetration = cp.getDistance()+infoGlobal.m_linearSlop;

				{
					btVector3 vel1,vel2;

					vel1 = rb0? rb0->getVelocityInLocalPoint(rel_pos1) : btVector3(0,0,0);
					vel2 = rb1? rb1->getVelocityInLocalPoint(rel_pos2) : btVector3(0,0,0);

	//			btVector3 vel2 = rb1 ? rb1->getVelocityInLocalPoint(rel_pos2) : btVector3(0,0,0);
					btVector3 vel  = vel1 - vel2;
					btScalar rel_vel = cp.m_normalWorldOnB.dot(vel);



					solverConstraint.m_friction = cp.m_combinedFriction;


					restitution =  restitutionCurve(rel_vel, cp.m_combinedRestitution);
					if (restitution <= btScalar(0.))
					{
						restitution = 0.f;
					};
				}


				///warm starting (or zero if disabled)
				if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
				{
					solverConstraint.m_appliedImpulse = cp.m_appliedImpulse * infoGlobal.m_warmstartingFactor;
					if (rb0)
						bodyA->internalApplyImpulse(solverConstraint.m_contactNormal1*bodyA->internalGetInvMass()*rb0->getLinearFactor(),solverConstraint.m_angularComponentA,solverConstraint.m_appliedImpulse);
					if (rb1)
						bodyB->internalApplyImpulse(-solverConstraint.m_contactNormal2*bodyB->internalGetInvMass()*rb1->getLinearFactor(),-solverConstraint.m_angularComponentB,-(btScalar)solverConstraint.m_appliedImpulse);
				} else
				{
					solverConstraint.m_appliedImpulse = 0.f;
				}

				solverConstraint.m_appliedPushImpulse = 0.f;

				{

					btVector3 externalForceImpulseA = bodyA->m_originalBody ? bodyA->m_externalForceImpulse: btVector3(0,0,0);
					btVector3 externalTorqueImpulseA = bodyA->m_originalBody ? bodyA->m_externalTorqueImpulse: btVector3(0,0,0);
					btVector3 externalForceImpulseB = bodyB->m_originalBody ? bodyB->m_externalForceImpulse: btVector3(0,0,0);
					btVector3 externalTorqueImpulseB = bodyB->m_originalBody ?bodyB->m_externalTorqueImpulse : btVector3(0,0,0);


					btScalar vel1Dotn = solverConstraint.m_contactNormal1.dot(bodyA->m_linearVelocity+externalForceImpulseA)
						+ solverConstraint.m_relpos1CrossNormal.dot(bodyA->m_angularVelocity+externalTorqueImpulseA);
					btScalar vel2Dotn = solverConstraint.m_contactNormal2.dot(bodyB->m_linearVelocity+externalForceImpulseB)
						+ solverConstraint.m_relpos2CrossNormal.dot(bodyB->m_angularVelocity+externalTorqueImpulseB);
					btScalar rel_vel = vel1Dotn+vel2Dotn;

					btScalar positionalError = 0.f;
					btScalar	velocityError = restitution - rel_vel;// * damping;


				
					if (penetration>0)
					{
						positionalError = 0;

						velocityError -= penetration *invTimeStep;
					} else
					{
						positionalError = -penetration * erp*invTimeStep;

					}

					btScalar  penetrationImpulse = positionalError*solverConstraint.m_jacDiagABInv;
					btScalar velocityImpulse = velocityError *solverConstraint.m_jacDiagABInv;

					if (!infoGlobal.m_splitImpulse || (penetration > infoGlobal.m_splitImpulsePenetrationThreshold))
					{
						//combine position and velocity into rhs
						solverConstraint.m_rhs = penetrationImpulse+velocityImpulse;//-solverConstraint.m_contactNormal1.dot(bodyA->m_externalForce*bodyA->m_invMass-bodyB->m_externalForce/bodyB->m_invMass)*solverConstraint.m_jacDiagABInv;
						solverConstraint.m_rhsPenetration = 0.f;

					} else
					{
						//split position and velocity into rhs and m_rhsPenetration
						solverConstraint.m_rhs = velocityImpulse;
						solverConstraint.m_rhsPenetration = penetrationImpulse;
					}
					solverConstraint.m_cfm = cfm*solverConstraint.m_jacDiagABInv;
					solverConstraint.m_lowerLimit = 0;
					solverConstraint.m_upperLimit = 1e10f;
				}




}



void btSequentialImpulseConstraintSolver::setFrictionConstraintImpulse( btSolverConstraint& solverConstraint,
																		int solverBodyIdA, int solverBodyIdB,
																 btManifoldPoint& cp, const btContactSolverInfo& infoGlobal)
{

	btSolverBody* bodyA = &m_tmpSolverBodyPool[solverBodyIdA];
	btSolverBody* bodyB = &m_tmpSolverBodyPool[solverBodyIdB];

	btRigidBody* rb0 = bodyA->m_originalBody;
	btRigidBody* rb1 = bodyB->m_originalBody;

	{
		btSolverConstraint& frictionConstraint1 = m_tmpSolverContactFrictionConstraintPool[solverConstraint.m_frictionIndex];
		if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
		{
			frictionConstraint1.m_appliedImpulse = cp.m_appliedImpulseLateral1 * infoGlobal.m_warmstartingFactor;
			if (rb0)
				bodyA->internalApplyImpulse(frictionConstraint1.m_contactNormal1*rb0->getInvMass()*rb0->getLinearFactor(),frictionConstraint1.m_angularComponentA,frictionConstraint1.m_appliedImpulse);
			if (rb1)
				bodyB->internalApplyImpulse(-frictionConstraint1.m_contactNormal2*rb1->getInvMass()*rb1->getLinearFactor(),-frictionConstraint1.m_angularComponentB,-(btScalar)frictionConstraint1.m_appliedImpulse);
		} else
		{
			frictionConstraint1.m_appliedImpulse = 0.f;
		}
	}

	if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
	{
		btSolverConstraint& frictionConstraint2 = m_tmpSolverContactFrictionConstraintPool[solverConstraint.m_frictionIndex+1];
		if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
		{
			frictionConstraint2.m_appliedImpulse = cp.m_appliedImpulseLateral2  * infoGlobal.m_warmstartingFactor;
			if (rb0)
				bodyA->internalApplyImpulse(frictionConstraint2.m_contactNormal1*rb0->getInvMass(),frictionConstraint2.m_angularComponentA,frictionConstraint2.m_appliedImpulse);
			if (rb1)
				bodyB->internalApplyImpulse(-frictionConstraint2.m_contactNormal2*rb1->getInvMass(),-frictionConstraint2.m_angularComponentB,-(btScalar)frictionConstraint2.m_appliedImpulse);
		} else
		{
			frictionConstraint2.m_appliedImpulse = 0.f;
		}
	}
}




void	btSequentialImpulseConstraintSolver::convertContact(btPersistentManifold* manifold,const btContactSolverInfo& infoGlobal)
{
	btCollisionObject* colObj0=0,*colObj1=0;

	colObj0 = (btCollisionObject*)manifold->getBody0();
	colObj1 = (btCollisionObject*)manifold->getBody1();

	int solverBodyIdA = getOrInitSolverBody(*colObj0,infoGlobal.m_timeStep);
	int solverBodyIdB = getOrInitSolverBody(*colObj1,infoGlobal.m_timeStep);

//	btRigidBody* bodyA = btRigidBody::upcast(colObj0);
//	btRigidBody* bodyB = btRigidBody::upcast(colObj1);

	btSolverBody* solverBodyA = &m_tmpSolverBodyPool[solverBodyIdA];
	btSolverBody* solverBodyB = &m_tmpSolverBodyPool[solverBodyIdB];



	///avoid collision response between two static objects
	if (!solverBodyA || (solverBodyA->m_invMass.fuzzyZero() && (!solverBodyB || solverBodyB->m_invMass.fuzzyZero())))
		return;

	int rollingFriction=1;
	for (int j=0;j<manifold->getNumContacts();j++)
	{

		btManifoldPoint& cp = manifold->getContactPoint(j);

		if (cp.getDistance() <= manifold->getContactProcessingThreshold())
		{
			btVector3 rel_pos1;
			btVector3 rel_pos2;
			btScalar relaxation;


			int frictionIndex = m_tmpSolverContactConstraintPool.size();
			btSolverConstraint& solverConstraint = m_tmpSolverContactConstraintPool.expandNonInitializing();
			solverConstraint.m_solverBodyIdA = solverBodyIdA;
			solverConstraint.m_solverBodyIdB = solverBodyIdB;

			solverConstraint.m_originalContactPoint = &cp;

			const btVector3& pos1 = cp.getPositionWorldOnA();
			const btVector3& pos2 = cp.getPositionWorldOnB();

			rel_pos1 = pos1 - colObj0->getWorldTransform().getOrigin();
			rel_pos2 = pos2 - colObj1->getWorldTransform().getOrigin();

			btVector3 vel1;
			btVector3 vel2;
			
			solverBodyA->getVelocityInLocalPointNoDelta(rel_pos1,vel1);
			solverBodyB->getVelocityInLocalPointNoDelta(rel_pos2,vel2 );

			btVector3 vel  = vel1 - vel2;
			btScalar rel_vel = cp.m_normalWorldOnB.dot(vel);

			setupContactConstraint(solverConstraint, solverBodyIdA, solverBodyIdB, cp, infoGlobal, relaxation, rel_pos1, rel_pos2);




			/////setup the friction constraints

			solverConstraint.m_frictionIndex = m_tmpSolverContactFrictionConstraintPool.size();

			if ((cp.m_combinedRollingFriction>0.f) && (rollingFriction>0))
			{
               
				{
					addTorsionalFrictionConstraint(cp.m_normalWorldOnB,solverBodyIdA,solverBodyIdB,frictionIndex,cp,cp.m_combinedSpinningFriction, rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
					btVector3 axis0,axis1;
					btPlaneSpace1(cp.m_normalWorldOnB,axis0,axis1);
					axis0.normalize();
					axis1.normalize();
					
					applyAnisotropicFriction(colObj0,axis0,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
					applyAnisotropicFriction(colObj1,axis0,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
					applyAnisotropicFriction(colObj0,axis1,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
					applyAnisotropicFriction(colObj1,axis1,btCollisionObject::CF_ANISOTROPIC_ROLLING_FRICTION);
					if (axis0.length()>0.001)
						addTorsionalFrictionConstraint(axis0,solverBodyIdA,solverBodyIdB,frictionIndex,cp,
                                                       cp.m_combinedRollingFriction, rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
					if (axis1.length()>0.001)
						addTorsionalFrictionConstraint(axis1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,
                                                       cp.m_combinedRollingFriction, rel_pos1,rel_pos2,colObj0,colObj1, relaxation);

				}
			}

			///Bullet has several options to set the friction directions
			///By default, each contact has only a single friction direction that is recomputed automatically very frame
			///based on the relative linear velocity.
			///If the relative velocity it zero, it will automatically compute a friction direction.

			///You can also enable two friction directions, using the SOLVER_USE_2_FRICTION_DIRECTIONS.
			///In that case, the second friction direction will be orthogonal to both contact normal and first friction direction.
			///
			///If you choose SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION, then the friction will be independent from the relative projected velocity.
			///
			///The user can manually override the friction directions for certain contacts using a contact callback,
			///and set the cp.m_lateralFrictionInitialized to true
			///In that case, you can set the target relative motion in each friction direction (cp.m_contactMotion1 and cp.m_contactMotion2)
			///this will give a conveyor belt effect
			///
			if (!(infoGlobal.m_solverMode & SOLVER_ENABLE_FRICTION_DIRECTION_CACHING) || !(cp.m_contactPointFlags&BT_CONTACT_FLAG_LATERAL_FRICTION_INITIALIZED))
			{
				cp.m_lateralFrictionDir1 = vel - cp.m_normalWorldOnB * rel_vel;
				btScalar lat_rel_vel = cp.m_lateralFrictionDir1.length2();
				if (!(infoGlobal.m_solverMode & SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION) && lat_rel_vel > SIMD_EPSILON)
				{
					cp.m_lateralFrictionDir1 *= 1.f/btSqrt(lat_rel_vel);
					applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
					applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
					addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);

					if((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
					{
						cp.m_lateralFrictionDir2 = cp.m_lateralFrictionDir1.cross(cp.m_normalWorldOnB);
						cp.m_lateralFrictionDir2.normalize();//??
						applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
						applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
						addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
					}

				} else
				{
					btPlaneSpace1(cp.m_normalWorldOnB,cp.m_lateralFrictionDir1,cp.m_lateralFrictionDir2);

					applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
					applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir1,btCollisionObject::CF_ANISOTROPIC_FRICTION);
					addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);

					if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
					{
						applyAnisotropicFriction(colObj0,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
						applyAnisotropicFriction(colObj1,cp.m_lateralFrictionDir2,btCollisionObject::CF_ANISOTROPIC_FRICTION);
						addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation);
					}


					if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS) && (infoGlobal.m_solverMode & SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION))
					{
						cp.m_contactPointFlags|=BT_CONTACT_FLAG_LATERAL_FRICTION_INITIALIZED;
					}
				}

			} else
			{
				addFrictionConstraint(cp.m_lateralFrictionDir1,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation,cp.m_contactMotion1, cp.m_frictionCFM);

				if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
					addFrictionConstraint(cp.m_lateralFrictionDir2,solverBodyIdA,solverBodyIdB,frictionIndex,cp,rel_pos1,rel_pos2,colObj0,colObj1, relaxation, cp.m_contactMotion2, cp.m_frictionCFM);

			}
			setFrictionConstraintImpulse( solverConstraint, solverBodyIdA, solverBodyIdB, cp, infoGlobal);




		}
	}
}

void btSequentialImpulseConstraintSolver::convertContacts(btPersistentManifold** manifoldPtr,int numManifolds, const btContactSolverInfo& infoGlobal)
{
	int i;
	btPersistentManifold* manifold = 0;
//			btCollisionObject* colObj0=0,*colObj1=0;


	for (i=0;i<numManifolds;i++)
	{
		manifold = manifoldPtr[i];
		convertContact(manifold,infoGlobal);
	}
}

btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCollisionObject** bodies, int numBodies, btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer)
{
	m_fixedBodyId = -1;
	BT_PROFILE("solveGroupCacheFriendlySetup");
	(void)debugDrawer;

	m_maxOverrideNumSolverIterations = 0;

#ifdef BT_ADDITIONAL_DEBUG
	 //make sure that dynamic bodies exist for all (enabled) constraints
	for (int i=0;i<numConstraints;i++)
	{
		btTypedConstraint* constraint = constraints[i];
		if (constraint->isEnabled())
		{
			if (!constraint->getRigidBodyA().isStaticOrKinematicObject())
			{
				bool found=false;
				for (int b=0;b<numBodies;b++)
				{

					if (&constraint->getRigidBodyA()==bodies[b])
					{
						found = true;
						break;
					}
				}
				btAssert(found);
			}
			if (!constraint->getRigidBodyB().isStaticOrKinematicObject())
			{
				bool found=false;
				for (int b=0;b<numBodies;b++)
				{
					if (&constraint->getRigidBodyB()==bodies[b])
					{
						found = true;
						break;
					}
				}
				btAssert(found);
			}
		}
	}
    //make sure that dynamic bodies exist for all contact manifolds
    for (int i=0;i<numManifolds;i++)
    {
        if (!manifoldPtr[i]->getBody0()->isStaticOrKinematicObject())
        {
            bool found=false;
            for (int b=0;b<numBodies;b++)
            {

                if (manifoldPtr[i]->getBody0()==bodies[b])
                {
                    found = true;
                    break;
                }
            }
            btAssert(found);
        }
        if (!manifoldPtr[i]->getBody1()->isStaticOrKinematicObject())
        {
            bool found=false;
            for (int b=0;b<numBodies;b++)
            {
                if (manifoldPtr[i]->getBody1()==bodies[b])
                {
                    found = true;
                    break;
                }
            }
            btAssert(found);
        }
    }
#endif //BT_ADDITIONAL_DEBUG


	for (int i = 0; i < numBodies; i++)
	{
		bodies[i]->setCompanionId(-1);
	}
#if BT_THREADSAFE
    m_kinematicBodyUniqueIdToSolverBodyTable.resize( 0 );
#endif // BT_THREADSAFE

	m_tmpSolverBodyPool.reserve(numBodies+1);
	m_tmpSolverBodyPool.resize(0);

	//btSolverBody& fixedBody = m_tmpSolverBodyPool.expand();
    //initSolverBody(&fixedBody,0);

	//convert all bodies


	for (int i=0;i<numBodies;i++)
	{
		int bodyId = getOrInitSolverBody(*bodies[i],infoGlobal.m_timeStep);

		btRigidBody* body = btRigidBody::upcast(bodies[i]);
		if (body && body->getInvMass())
		{
			btSolverBody& solverBody = m_tmpSolverBodyPool[bodyId];
			btVector3 gyroForce (0,0,0);
			if (body->getFlags()&BT_ENABLE_GYROSCOPIC_FORCE_EXPLICIT)
			{
				gyroForce = body->computeGyroscopicForceExplicit(infoGlobal.m_maxGyroscopicForce);
				solverBody.m_externalTorqueImpulse -= gyroForce*body->getInvInertiaTensorWorld()*infoGlobal.m_timeStep;
			}
			if (body->getFlags()&BT_ENABLE_GYROSCOPIC_FORCE_IMPLICIT_WORLD)
			{
				gyroForce = body->computeGyroscopicImpulseImplicit_World(infoGlobal.m_timeStep);
				solverBody.m_externalTorqueImpulse += gyroForce;
			}
			if (body->getFlags()&BT_ENABLE_GYROSCOPIC_FORCE_IMPLICIT_BODY)
			{
				gyroForce = body->computeGyroscopicImpulseImplicit_Body(infoGlobal.m_timeStep);
				solverBody.m_externalTorqueImpulse += gyroForce;

			}
			

		}
	}

	if (1)
	{
		int j;
		for (j=0;j<numConstraints;j++)
		{
			btTypedConstraint* constraint = constraints[j];
			constraint->buildJacobian();
			constraint->internalSetAppliedImpulse(0.0f);
		}
	}

	//btRigidBody* rb0=0,*rb1=0;

	//if (1)
	{
		{

			int totalNumRows = 0;
			int i;

			m_tmpConstraintSizesPool.resizeNoInitialize(numConstraints);
			//calculate the total number of contraint rows
			for (i=0;i<numConstraints;i++)
			{
				btTypedConstraint::btConstraintInfo1& info1 = m_tmpConstraintSizesPool[i];
				btJointFeedback* fb = constraints[i]->getJointFeedback();
				if (fb)
				{
					fb->m_appliedForceBodyA.setZero();
					fb->m_appliedTorqueBodyA.setZero();
					fb->m_appliedForceBodyB.setZero();
					fb->m_appliedTorqueBodyB.setZero();
				}

				if (constraints[i]->isEnabled())
				{
				}
				if (constraints[i]->isEnabled())
				{
					constraints[i]->getInfo1(&info1);
				} else
				{
					info1.m_numConstraintRows = 0;
					info1.nub = 0;
				}
				totalNumRows += info1.m_numConstraintRows;
			}
			m_tmpSolverNonContactConstraintPool.resizeNoInitialize(totalNumRows);


			///setup the btSolverConstraints
			int currentRow = 0;

			for (i=0;i<numConstraints;i++)
			{
				const btTypedConstraint::btConstraintInfo1& info1 = m_tmpConstraintSizesPool[i];

				if (info1.m_numConstraintRows)
				{
					btAssert(currentRow<totalNumRows);

					btSolverConstraint* currentConstraintRow = &m_tmpSolverNonContactConstraintPool[currentRow];
					btTypedConstraint* constraint = constraints[i];
					btRigidBody& rbA = constraint->getRigidBodyA();
					btRigidBody& rbB = constraint->getRigidBodyB();

					int solverBodyIdA = getOrInitSolverBody(rbA,infoGlobal.m_timeStep);
                    int solverBodyIdB = getOrInitSolverBody(rbB,infoGlobal.m_timeStep);

                    btSolverBody* bodyAPtr = &m_tmpSolverBodyPool[solverBodyIdA];
                    btSolverBody* bodyBPtr = &m_tmpSolverBodyPool[solverBodyIdB];




					int overrideNumSolverIterations = constraint->getOverrideNumSolverIterations() > 0 ? constraint->getOverrideNumSolverIterations() : infoGlobal.m_numIterations;
					if (overrideNumSolverIterations>m_maxOverrideNumSolverIterations)
						m_maxOverrideNumSolverIterations = overrideNumSolverIterations;


					int j;
					for ( j=0;j<info1.m_numConstraintRows;j++)
					{
						memset(&currentConstraintRow[j],0,sizeof(btSolverConstraint));
						currentConstraintRow[j].m_lowerLimit = -SIMD_INFINITY;
						currentConstraintRow[j].m_upperLimit = SIMD_INFINITY;
						currentConstraintRow[j].m_appliedImpulse = 0.f;
						currentConstraintRow[j].m_appliedPushImpulse = 0.f;
						currentConstraintRow[j].m_solverBodyIdA = solverBodyIdA;
						currentConstraintRow[j].m_solverBodyIdB = solverBodyIdB;
						currentConstraintRow[j].m_overrideNumSolverIterations = overrideNumSolverIterations;
					}

					bodyAPtr->internalGetDeltaLinearVelocity().setValue(0.f,0.f,0.f);
					bodyAPtr->internalGetDeltaAngularVelocity().setValue(0.f,0.f,0.f);
					bodyAPtr->internalGetPushVelocity().setValue(0.f,0.f,0.f);
					bodyAPtr->internalGetTurnVelocity().setValue(0.f,0.f,0.f);
					bodyBPtr->internalGetDeltaLinearVelocity().setValue(0.f,0.f,0.f);
					bodyBPtr->internalGetDeltaAngularVelocity().setValue(0.f,0.f,0.f);
					bodyBPtr->internalGetPushVelocity().setValue(0.f,0.f,0.f);
					bodyBPtr->internalGetTurnVelocity().setValue(0.f,0.f,0.f);


					btTypedConstraint::btConstraintInfo2 info2;
					info2.fps = 1.f/infoGlobal.m_timeStep;
					info2.erp = infoGlobal.m_erp;
					info2.m_J1linearAxis = currentConstraintRow->m_contactNormal1;
					info2.m_J1angularAxis = currentConstraintRow->m_relpos1CrossNormal;
					info2.m_J2linearAxis = currentConstraintRow->m_contactNormal2;
					info2.m_J2angularAxis = currentConstraintRow->m_relpos2CrossNormal;
					info2.rowskip = sizeof(btSolverConstraint)/sizeof(btScalar);//check this
					///the size of btSolverConstraint needs be a multiple of btScalar
		            btAssert(info2.rowskip*sizeof(btScalar)== sizeof(btSolverConstraint));
					info2.m_constraintError = &currentConstraintRow->m_rhs;
					currentConstraintRow->m_cfm = infoGlobal.m_globalCfm;
					info2.m_damping = infoGlobal.m_damping;
					info2.cfm = &currentConstraintRow->m_cfm;
					info2.m_lowerLimit = &currentConstraintRow->m_lowerLimit;
					info2.m_upperLimit = &currentConstraintRow->m_upperLimit;
					info2.m_numIterations = infoGlobal.m_numIterations;
					constraints[i]->getInfo2(&info2);

					///finalize the constraint setup
					for ( j=0;j<info1.m_numConstraintRows;j++)
					{
						btSolverConstraint& solverConstraint = currentConstraintRow[j];

						if (solverConstraint.m_upperLimit>=constraints[i]->getBreakingImpulseThreshold())
						{
							solverConstraint.m_upperLimit = constraints[i]->getBreakingImpulseThreshold();
						}

						if (solverConstraint.m_lowerLimit<=-constraints[i]->getBreakingImpulseThreshold())
						{
							solverConstraint.m_lowerLimit = -constraints[i]->getBreakingImpulseThreshold();
						}

						solverConstraint.m_originalContactPoint = constraint;

						{
							const btVector3& ftorqueAxis1 = solverConstraint.m_relpos1CrossNormal;
							solverConstraint.m_angularComponentA = constraint->getRigidBodyA().getInvInertiaTensorWorld()*ftorqueAxis1*constraint->getRigidBodyA().getAngularFactor();
						}
						{
							const btVector3& ftorqueAxis2 = solverConstraint.m_relpos2CrossNormal;
							solverConstraint.m_angularComponentB = constraint->getRigidBodyB().getInvInertiaTensorWorld()*ftorqueAxis2*constraint->getRigidBodyB().getAngularFactor();
						}

						{
							btVector3 iMJlA = solverConstraint.m_contactNormal1*rbA.getInvMass();
							btVector3 iMJaA = rbA.getInvInertiaTensorWorld()*solverConstraint.m_relpos1CrossNormal;
							btVector3 iMJlB = solverConstraint.m_contactNormal2*rbB.getInvMass();//sign of normal?
							btVector3 iMJaB = rbB.getInvInertiaTensorWorld()*solverConstraint.m_relpos2CrossNormal;

							btScalar sum = iMJlA.dot(solverConstraint.m_contactNormal1);
							sum += iMJaA.dot(solverConstraint.m_relpos1CrossNormal);
							sum += iMJlB.dot(solverConstraint.m_contactNormal2);
							sum += iMJaB.dot(solverConstraint.m_relpos2CrossNormal);
							btScalar fsum = btFabs(sum);
							btAssert(fsum > SIMD_EPSILON);
							solverConstraint.m_jacDiagABInv = fsum>SIMD_EPSILON?btScalar(1.)/sum : 0.f;
						}



						{
							btScalar rel_vel;
							btVector3 externalForceImpulseA = bodyAPtr->m_originalBody ? bodyAPtr->m_externalForceImpulse : btVector3(0,0,0);
							btVector3 externalTorqueImpulseA = bodyAPtr->m_originalBody ? bodyAPtr->m_externalTorqueImpulse : btVector3(0,0,0);

							btVector3 externalForceImpulseB = bodyBPtr->m_originalBody ? bodyBPtr->m_externalForceImpulse : btVector3(0,0,0);
							btVector3 externalTorqueImpulseB = bodyBPtr->m_originalBody ?bodyBPtr->m_externalTorqueImpulse : btVector3(0,0,0);

							btScalar vel1Dotn = solverConstraint.m_contactNormal1.dot(rbA.getLinearVelocity()+externalForceImpulseA)
												+ solverConstraint.m_relpos1CrossNormal.dot(rbA.getAngularVelocity()+externalTorqueImpulseA);

							btScalar vel2Dotn = solverConstraint.m_contactNormal2.dot(rbB.getLinearVelocity()+externalForceImpulseB)
																+ solverConstraint.m_relpos2CrossNormal.dot(rbB.getAngularVelocity()+externalTorqueImpulseB);

							rel_vel = vel1Dotn+vel2Dotn;
							btScalar restitution = 0.f;
							btScalar positionalError = solverConstraint.m_rhs;//already filled in by getConstraintInfo2
							btScalar	velocityError = restitution - rel_vel * info2.m_damping;
							btScalar	penetrationImpulse = positionalError*solverConstraint.m_jacDiagABInv;
							btScalar	velocityImpulse = velocityError *solverConstraint.m_jacDiagABInv;
							solverConstraint.m_rhs = penetrationImpulse+velocityImpulse;
							solverConstraint.m_appliedImpulse = 0.f;


						}
					}
				}
				currentRow+=m_tmpConstraintSizesPool[i].m_numConstraintRows;
			}
		}

		convertContacts(manifoldPtr,numManifolds,infoGlobal);

	}

//	btContactSolverInfo info = infoGlobal;


	int numNonContactPool = m_tmpSolverNonContactConstraintPool.size();
	int numConstraintPool = m_tmpSolverContactConstraintPool.size();
	int numFrictionPool = m_tmpSolverContactFrictionConstraintPool.size();

	///@todo: use stack allocator for such temporarily memory, same for solver bodies/constraints
	m_orderNonContactConstraintPool.resizeNoInitialize(numNonContactPool);
	if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
		m_orderTmpConstraintPool.resizeNoInitialize(numConstraintPool*2);
	else
		m_orderTmpConstraintPool.resizeNoInitialize(numConstraintPool);

	m_orderFrictionConstraintPool.resizeNoInitialize(numFrictionPool);
	{
		int i;
		for (i=0;i<numNonContactPool;i++)
		{
			m_orderNonContactConstraintPool[i] = i;
		}
		for (i=0;i<numConstraintPool;i++)
		{
			m_orderTmpConstraintPool[i] = i;
		}
		for (i=0;i<numFrictionPool;i++)
		{
			m_orderFrictionConstraintPool[i] = i;
		}
	}

	return 0.f;

}


btScalar btSequentialImpulseConstraintSolver::solveSingleIteration(int iteration, btCollisionObject** /*bodies */,int /*numBodies*/,btPersistentManifold** /*manifoldPtr*/, int /*numManifolds*/,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* /*debugDrawer*/)
{
	btScalar leastSquaresResidual = 0.f;

	int numNonContactPool = m_tmpSolverNonContactConstraintPool.size();
	int numConstraintPool = m_tmpSolverContactConstraintPool.size();
	int numFrictionPool = m_tmpSolverContactFrictionConstraintPool.size();

	if (infoGlobal.m_solverMode & SOLVER_RANDMIZE_ORDER)
	{
		if (1)			// uncomment this for a bit less random ((iteration & 7) == 0)
		{

			for (int j=0; j<numNonContactPool; ++j) {
				int tmp = m_orderNonContactConstraintPool[j];
				int swapi = btRandInt2(j+1);
				m_orderNonContactConstraintPool[j] = m_orderNonContactConstraintPool[swapi];
				m_orderNonContactConstraintPool[swapi] = tmp;
			}

			//contact/friction constraints are not solved more than
			if (iteration< infoGlobal.m_numIterations)
			{
				for (int j=0; j<numConstraintPool; ++j) {
					int tmp = m_orderTmpConstraintPool[j];
					int swapi = btRandInt2(j+1);
					m_orderTmpConstraintPool[j] = m_orderTmpConstraintPool[swapi];
					m_orderTmpConstraintPool[swapi] = tmp;
				}

				for (int j=0; j<numFrictionPool; ++j) {
					int tmp = m_orderFrictionConstraintPool[j];
					int swapi = btRandInt2(j+1);
					m_orderFrictionConstraintPool[j] = m_orderFrictionConstraintPool[swapi];
					m_orderFrictionConstraintPool[swapi] = tmp;
				}
			}
		}
	}

	if (infoGlobal.m_solverMode & SOLVER_SIMD)
	{
		///solve all joint constraints, using SIMD, if available
		for (int j=0;j<m_tmpSolverNonContactConstraintPool.size();j++)
		{
			btSolverConstraint& constraint = m_tmpSolverNonContactConstraintPool[m_orderNonContactConstraintPool[j]];
			if (iteration < constraint.m_overrideNumSolverIterations)
			{
				btScalar residual = resolveSingleConstraintRowGenericSIMD(m_tmpSolverBodyPool[constraint.m_solverBodyIdA],m_tmpSolverBodyPool[constraint.m_solverBodyIdB],constraint);
				leastSquaresResidual += residual*residual;
			}
		}

		if (iteration< infoGlobal.m_numIterations)
		{
			for (int j=0;j<numConstraints;j++)
			{
				if (constraints[j]->isEnabled())
				{
					int bodyAid = getOrInitSolverBody(constraints[j]->getRigidBodyA(),infoGlobal.m_timeStep);
					int bodyBid = getOrInitSolverBody(constraints[j]->getRigidBodyB(),infoGlobal.m_timeStep);
					btSolverBody& bodyA = m_tmpSolverBodyPool[bodyAid];
					btSolverBody& bodyB = m_tmpSolverBodyPool[bodyBid];
					constraints[j]->solveConstraintObsolete(bodyA,bodyB,infoGlobal.m_timeStep);
				}
			}

			///solve all contact constraints using SIMD, if available
			if (infoGlobal.m_solverMode & SOLVER_INTERLEAVE_CONTACT_AND_FRICTION_CONSTRAINTS)
			{
				int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
				int multiplier = (infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS)? 2 : 1;

				for (int c=0;c<numPoolConstraints;c++)
				{
					btScalar totalImpulse =0;

					{
						const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[c]];
						btScalar residual = resolveSingleConstraintRowLowerLimitSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
						leastSquaresResidual += residual*residual;

						totalImpulse = solveManifold.m_appliedImpulse;
					}
					bool applyFriction = true;
					if (applyFriction)
					{
						{

							btSolverConstraint& solveManifold = m_tmpSolverContactFrictionConstraintPool[m_orderFrictionConstraintPool[c*multiplier]];

							if (totalImpulse>btScalar(0))
							{
								solveManifold.m_lowerLimit = -(solveManifold.m_friction*totalImpulse);
								solveManifold.m_upperLimit = solveManifold.m_friction*totalImpulse;

								btScalar residual = resolveSingleConstraintRowGenericSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
								leastSquaresResidual += residual*residual;
							}
						}

						if (infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS)
						{

							btSolverConstraint& solveManifold = m_tmpSolverContactFrictionConstraintPool[m_orderFrictionConstraintPool[c*multiplier+1]];

							if (totalImpulse>btScalar(0))
							{
								solveManifold.m_lowerLimit = -(solveManifold.m_friction*totalImpulse);
								solveManifold.m_upperLimit = solveManifold.m_friction*totalImpulse;

								btScalar residual = resolveSingleConstraintRowGenericSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
								leastSquaresResidual += residual*residual;
							}
						}
					}
				}

			}
			else//SOLVER_INTERLEAVE_CONTACT_AND_FRICTION_CONSTRAINTS
			{
				//solve the friction constraints after all contact constraints, don't interleave them
				int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
				int j;

				for (j=0;j<numPoolConstraints;j++)
				{
					const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[j]];
					btScalar residual = resolveSingleConstraintRowLowerLimitSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
					leastSquaresResidual += residual*residual;
				}



				///solve all friction constraints, using SIMD, if available

				int numFrictionPoolConstraints = m_tmpSolverContactFrictionConstraintPool.size();
				for (j=0;j<numFrictionPoolConstraints;j++)
				{
					btSolverConstraint& solveManifold = m_tmpSolverContactFrictionConstraintPool[m_orderFrictionConstraintPool[j]];
					btScalar totalImpulse = m_tmpSolverContactConstraintPool[solveManifold.m_frictionIndex].m_appliedImpulse;

					if (totalImpulse>btScalar(0))
					{
						solveManifold.m_lowerLimit = -(solveManifold.m_friction*totalImpulse);
						solveManifold.m_upperLimit = solveManifold.m_friction*totalImpulse;

						btScalar residual = resolveSingleConstraintRowGenericSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
						leastSquaresResidual += residual*residual;
					}
				}


				int numRollingFrictionPoolConstraints = m_tmpSolverContactRollingFrictionConstraintPool.size();
				for (j=0;j<numRollingFrictionPoolConstraints;j++)
				{

					btSolverConstraint& rollingFrictionConstraint = m_tmpSolverContactRollingFrictionConstraintPool[j];
					btScalar totalImpulse = m_tmpSolverContactConstraintPool[rollingFrictionConstraint.m_frictionIndex].m_appliedImpulse;
					if (totalImpulse>btScalar(0))
					{
						btScalar rollingFrictionMagnitude = rollingFrictionConstraint.m_friction*totalImpulse;
						if (rollingFrictionMagnitude>rollingFrictionConstraint.m_friction)
							rollingFrictionMagnitude = rollingFrictionConstraint.m_friction;

						rollingFrictionConstraint.m_lowerLimit = -rollingFrictionMagnitude;
						rollingFrictionConstraint.m_upperLimit = rollingFrictionMagnitude;

						btScalar residual = resolveSingleConstraintRowGenericSIMD(m_tmpSolverBodyPool[rollingFrictionConstraint.m_solverBodyIdA],m_tmpSolverBodyPool[rollingFrictionConstraint.m_solverBodyIdB],rollingFrictionConstraint);
						leastSquaresResidual += residual*residual;
					}
				}


			}
		}
	} else
	{
		//non-SIMD version
		///solve all joint constraints
		for (int j=0;j<m_tmpSolverNonContactConstraintPool.size();j++)
		{
			btSolverConstraint& constraint = m_tmpSolverNonContactConstraintPool[m_orderNonContactConstraintPool[j]];
			if (iteration < constraint.m_overrideNumSolverIterations)
			{
				btScalar residual = resolveSingleConstraintRowGeneric(m_tmpSolverBodyPool[constraint.m_solverBodyIdA],m_tmpSolverBodyPool[constraint.m_solverBodyIdB],constraint);
				leastSquaresResidual += residual*residual;
			}
		}

		if (iteration< infoGlobal.m_numIterations)
		{
			for (int j=0;j<numConstraints;j++)
			{
				if (constraints[j]->isEnabled())
				{
					int bodyAid = getOrInitSolverBody(constraints[j]->getRigidBodyA(),infoGlobal.m_timeStep);
					int bodyBid = getOrInitSolverBody(constraints[j]->getRigidBodyB(),infoGlobal.m_timeStep);
					btSolverBody& bodyA = m_tmpSolverBodyPool[bodyAid];
					btSolverBody& bodyB = m_tmpSolverBodyPool[bodyBid];
					constraints[j]->solveConstraintObsolete(bodyA,bodyB,infoGlobal.m_timeStep);
				}
			}
			///solve all contact constraints
			int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
			for (int j=0;j<numPoolConstraints;j++)
			{
				const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[j]];
				btScalar residual = resolveSingleConstraintRowLowerLimit(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
				leastSquaresResidual += residual*residual;
			}
			///solve all friction constraints
			int numFrictionPoolConstraints = m_tmpSolverContactFrictionConstraintPool.size();
			for (int j=0;j<numFrictionPoolConstraints;j++)
			{
				btSolverConstraint& solveManifold = m_tmpSolverContactFrictionConstraintPool[m_orderFrictionConstraintPool[j]];
				btScalar totalImpulse = m_tmpSolverContactConstraintPool[solveManifold.m_frictionIndex].m_appliedImpulse;

				if (totalImpulse>btScalar(0))
				{
					solveManifold.m_lowerLimit = -(solveManifold.m_friction*totalImpulse);
					solveManifold.m_upperLimit = solveManifold.m_friction*totalImpulse;

					btScalar residual = resolveSingleConstraintRowGeneric(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
					leastSquaresResidual += residual*residual;
				}
			}

			int numRollingFrictionPoolConstraints = m_tmpSolverContactRollingFrictionConstraintPool.size();
			for (int j=0;j<numRollingFrictionPoolConstraints;j++)
			{
				btSolverConstraint& rollingFrictionConstraint = m_tmpSolverContactRollingFrictionConstraintPool[j];
				btScalar totalImpulse = m_tmpSolverContactConstraintPool[rollingFrictionConstraint.m_frictionIndex].m_appliedImpulse;
				if (totalImpulse>btScalar(0))
				{
					btScalar rollingFrictionMagnitude = rollingFrictionConstraint.m_friction*totalImpulse;
					if (rollingFrictionMagnitude>rollingFrictionConstraint.m_friction)
						rollingFrictionMagnitude = rollingFrictionConstraint.m_friction;

					rollingFrictionConstraint.m_lowerLimit = -rollingFrictionMagnitude;
					rollingFrictionConstraint.m_upperLimit = rollingFrictionMagnitude;

					btScalar residual = resolveSingleConstraintRowGeneric(m_tmpSolverBodyPool[rollingFrictionConstraint.m_solverBodyIdA],m_tmpSolverBodyPool[rollingFrictionConstraint.m_solverBodyIdB],rollingFrictionConstraint);
					leastSquaresResidual += residual*residual;
				}
			}
		}
	}
	return leastSquaresResidual;
}


void btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySplitImpulseIterations(btCollisionObject** bodies,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer)
{
	int iteration;
	if (infoGlobal.m_splitImpulse)
	{
		if (infoGlobal.m_solverMode & SOLVER_SIMD)
		{
			for ( iteration = 0;iteration<infoGlobal.m_numIterations;iteration++)
			{
				btScalar leastSquaresResidual =0.f;
				{
					int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
					int j;
					for (j=0;j<numPoolConstraints;j++)
					{
						const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[j]];

						btScalar residual = resolveSplitPenetrationSIMD(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
						leastSquaresResidual += residual*residual;
					}
				}
				if (leastSquaresResidual <= infoGlobal.m_leastSquaresResidualThreshold || iteration>=(infoGlobal.m_numIterations-1))
				{
#ifdef VERBOSE_RESIDUAL_PRINTF
					printf("residual = %f at iteration #%d\n",leastSquaresResidual,iteration);
#endif
					break;
				}
			}
		}
		else
		{
			for ( iteration = 0;iteration<infoGlobal.m_numIterations;iteration++)
			{
				btScalar leastSquaresResidual = 0.f;
				{
					int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
					int j;
					for (j=0;j<numPoolConstraints;j++)
					{
						const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[m_orderTmpConstraintPool[j]];

						btScalar residual = resolveSplitPenetrationImpulseCacheFriendly(m_tmpSolverBodyPool[solveManifold.m_solverBodyIdA],m_tmpSolverBodyPool[solveManifold.m_solverBodyIdB],solveManifold);
						leastSquaresResidual += residual*residual;
					}
					if (leastSquaresResidual <= infoGlobal.m_leastSquaresResidualThreshold || iteration>=(infoGlobal.m_numIterations-1))
					{
#ifdef VERBOSE_RESIDUAL_PRINTF
						printf("residual = %f at iteration #%d\n",leastSquaresResidual,iteration);
#endif
						break;
					}
				}
			}
		}
	}
}

btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlyIterations(btCollisionObject** bodies ,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer)
{
	BT_PROFILE("solveGroupCacheFriendlyIterations");

	{
		///this is a special step to resolve penetrations (just for contacts)
		solveGroupCacheFriendlySplitImpulseIterations(bodies ,numBodies,manifoldPtr, numManifolds,constraints,numConstraints,infoGlobal,debugDrawer);

		int maxIterations = m_maxOverrideNumSolverIterations > infoGlobal.m_numIterations? m_maxOverrideNumSolverIterations : infoGlobal.m_numIterations;

		for ( int iteration = 0 ; iteration< maxIterations ; iteration++)
		//for ( int iteration = maxIterations-1  ; iteration >= 0;iteration--)
		{
			m_leastSquaresResidual = solveSingleIteration(iteration, bodies ,numBodies,manifoldPtr, numManifolds,constraints,numConstraints,infoGlobal,debugDrawer);

			if (m_leastSquaresResidual <= infoGlobal.m_leastSquaresResidualThreshold || (iteration>= (maxIterations-1)))
			{
#ifdef VERBOSE_RESIDUAL_PRINTF
						printf("residual = %f at iteration #%d\n",m_leastSquaresResidual,iteration);
#endif
				break;
			}
		}

	}
	return 0.f;
}

btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlyFinish(btCollisionObject** bodies,int numBodies,const btContactSolverInfo& infoGlobal)
{
	int numPoolConstraints = m_tmpSolverContactConstraintPool.size();
	int i,j;

	if (infoGlobal.m_solverMode & SOLVER_USE_WARMSTARTING)
	{
		for (j=0;j<numPoolConstraints;j++)
		{
			const btSolverConstraint& solveManifold = m_tmpSolverContactConstraintPool[j];
			btManifoldPoint* pt = (btManifoldPoint*) solveManifold.m_originalContactPoint;
			btAssert(pt);
			pt->m_appliedImpulse = solveManifold.m_appliedImpulse;
		//	float f = m_tmpSolverContactFrictionConstraintPool[solveManifold.m_frictionIndex].m_appliedImpulse;
			//	printf("pt->m_appliedImpulseLateral1 = %f\n", f);
			pt->m_appliedImpulseLateral1 = m_tmpSolverContactFrictionConstraintPool[solveManifold.m_frictionIndex].m_appliedImpulse;
			//printf("pt->m_appliedImpulseLateral1 = %f\n", pt->m_appliedImpulseLateral1);
			if ((infoGlobal.m_solverMode & SOLVER_USE_2_FRICTION_DIRECTIONS))
			{
				pt->m_appliedImpulseLateral2 = m_tmpSolverContactFrictionConstraintPool[solveManifold.m_frictionIndex+1].m_appliedImpulse;
			}
			//do a callback here?
		}
	}

	numPoolConstraints = m_tmpSolverNonContactConstraintPool.size();
	for (j=0;j<numPoolConstraints;j++)
	{
		const btSolverConstraint& solverConstr = m_tmpSolverNonContactConstraintPool[j];
		btTypedConstraint* constr = (btTypedConstraint*)solverConstr.m_originalContactPoint;
		btJointFeedback* fb = constr->getJointFeedback();
		if (fb)
		{
			fb->m_appliedForceBodyA += solverConstr.m_contactNormal1*solverConstr.m_appliedImpulse*constr->getRigidBodyA().getLinearFactor()/infoGlobal.m_timeStep;
			fb->m_appliedForceBodyB += solverConstr.m_contactNormal2*solverConstr.m_appliedImpulse*constr->getRigidBodyB().getLinearFactor()/infoGlobal.m_timeStep;
			fb->m_appliedTorqueBodyA += solverConstr.m_relpos1CrossNormal* constr->getRigidBodyA().getAngularFactor()*solverConstr.m_appliedImpulse/infoGlobal.m_timeStep;
			fb->m_appliedTorqueBodyB += solverConstr.m_relpos2CrossNormal* constr->getRigidBodyB().getAngularFactor()*solverConstr.m_appliedImpulse/infoGlobal.m_timeStep; /*RGM ???? */

		}

		constr->internalSetAppliedImpulse(solverConstr.m_appliedImpulse);
		// Urho3D: if constraint has infinity breaking threshold, do not break no matter what
        btScalar breakingThreshold = constr->getBreakingImpulseThreshold();
		if (breakingThreshold < SIMD_INFINITY && btFabs(solverConstr.m_appliedImpulse)>=breakingThreshold)
		{
			constr->setEnabled(false);
		}
	}



	for ( i=0;i<m_tmpSolverBodyPool.size();i++)
	{
		btRigidBody* body = m_tmpSolverBodyPool[i].m_originalBody;
		if (body)
		{
			if (infoGlobal.m_splitImpulse)
				m_tmpSolverBodyPool[i].writebackVelocityAndTransform(infoGlobal.m_timeStep, infoGlobal.m_splitImpulseTurnErp);
			else
				m_tmpSolverBodyPool[i].writebackVelocity();

			m_tmpSolverBodyPool[i].m_originalBody->setLinearVelocity(
				m_tmpSolverBodyPool[i].m_linearVelocity+
				m_tmpSolverBodyPool[i].m_externalForceImpulse);

			m_tmpSolverBodyPool[i].m_originalBody->setAngularVelocity(
				m_tmpSolverBodyPool[i].m_angularVelocity+
				m_tmpSolverBodyPool[i].m_externalTorqueImpulse);

			if (infoGlobal.m_splitImpulse)
				m_tmpSolverBodyPool[i].m_originalBody->setWorldTransform(m_tmpSolverBodyPool[i].m_worldTransform);

			m_tmpSolverBodyPool[i].m_originalBody->setCompanionId(-1);
		}
	}

	m_tmpSolverContactConstraintPool.resizeNoInitialize(0);
	m_tmpSolverNonContactConstraintPool.resizeNoInitialize(0);
	m_tmpSolverContactFrictionConstraintPool.resizeNoInitialize(0);
	m_tmpSolverContactRollingFrictionConstraintPool.resizeNoInitialize(0);

	m_tmpSolverBodyPool.resizeNoInitialize(0);
	return 0.f;
}



/// btSequentialImpulseConstraintSolver Sequentially applies impulses
btScalar btSequentialImpulseConstraintSolver::solveGroup(btCollisionObject** bodies,int numBodies,btPersistentManifold** manifoldPtr, int numManifolds,btTypedConstraint** constraints,int numConstraints,const btContactSolverInfo& infoGlobal,btIDebugDraw* debugDrawer,btDispatcher* /*dispatcher*/)
{

	BT_PROFILE("solveGroup");
	//you need to provide at least some bodies

	solveGroupCacheFriendlySetup( bodies, numBodies, manifoldPtr,  numManifolds,constraints, numConstraints,infoGlobal,debugDrawer);

	solveGroupCacheFriendlyIterations(bodies, numBodies, manifoldPtr,  numManifolds,constraints, numConstraints,infoGlobal,debugDrawer);

	solveGroupCacheFriendlyFinish(bodies, numBodies, infoGlobal);

	return 0.f;
}

void	btSequentialImpulseConstraintSolver::reset()
{
	m_btSeed2 = 0;
}