virtualx-engine/thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodySolverConstraint.h

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2013 Erwin Coumans  http://bulletphysics.org

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_MULTIBODY_SOLVER_CONSTRAINT_H
#define BT_MULTIBODY_SOLVER_CONSTRAINT_H

#include "LinearMath/btVector3.h"
#include "LinearMath/btAlignedObjectArray.h"

class btMultiBody;
class btMultiBodyConstraint;
#include "BulletDynamics/ConstraintSolver/btSolverBody.h"
#include "BulletDynamics/ConstraintSolver/btContactSolverInfo.h"

///1D constraint along a normal axis between bodyA and bodyB. It can be combined to solve contact and friction constraints.
ATTRIBUTE_ALIGNED16(struct)
btMultiBodySolverConstraint
{
	BT_DECLARE_ALIGNED_ALLOCATOR();

	btMultiBodySolverConstraint() : m_solverBodyIdA(-1), m_multiBodyA(0), m_linkA(-1), m_solverBodyIdB(-1), m_multiBodyB(0), m_linkB(-1), m_orgConstraint(0), m_orgDofIndex(-1)
	{
	}

	int m_deltaVelAindex;  //more generic version of m_relpos1CrossNormal/m_contactNormal1
	int m_jacAindex;
	int m_deltaVelBindex;
	int m_jacBindex;

	btVector3 m_relpos1CrossNormal;
	btVector3 m_contactNormal1;
	btVector3 m_relpos2CrossNormal;
	btVector3 m_contactNormal2;  //usually m_contactNormal2 == -m_contactNormal1, but not always

	btVector3 m_angularComponentA;
	btVector3 m_angularComponentB;

	mutable btSimdScalar m_appliedPushImpulse;
	mutable btSimdScalar m_appliedImpulse;

	btScalar m_friction;
	btScalar m_jacDiagABInv;
	btScalar m_rhs;
	btScalar m_cfm;

	btScalar m_lowerLimit;
	btScalar m_upperLimit;
	btScalar m_rhsPenetration;
	union {
		void* m_originalContactPoint;
		btScalar m_unusedPadding4;
	};

	int m_overrideNumSolverIterations;
	int m_frictionIndex;

	int m_solverBodyIdA;
	btMultiBody* m_multiBodyA;
	int m_linkA;

	int m_solverBodyIdB;
	btMultiBody* m_multiBodyB;
	int m_linkB;

	//for writing back applied impulses
	btMultiBodyConstraint* m_orgConstraint;
	int m_orgDofIndex;

	enum btSolverConstraintType
	{
		BT_SOLVER_CONTACT_1D = 0,
		BT_SOLVER_FRICTION_1D
	};
};

typedef btAlignedObjectArray<btMultiBodySolverConstraint> btMultiBodyConstraintArray;

#endif  //BT_MULTIBODY_SOLVER_CONSTRAINT_H