| /* |
| 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 JACOBIAN_ENTRY_H |
| #define JACOBIAN_ENTRY_H |
| |
| #include "LinearMath/btVector3.h" |
| #include "BulletDynamics/Dynamics/btRigidBody.h" |
| |
| |
| //notes: |
| // Another memory optimization would be to store m_1MinvJt in the remaining 3 w components |
| // which makes the btJacobianEntry memory layout 16 bytes |
| // if you only are interested in angular part, just feed massInvA and massInvB zero |
| |
| /// Jacobian entry is an abstraction that allows to describe constraints |
| /// it can be used in combination with a constraint solver |
| /// Can be used to relate the effect of an impulse to the constraint error |
| ATTRIBUTE_ALIGNED16(class) btJacobianEntry |
| { |
| public: |
| btJacobianEntry() {}; |
| //constraint between two different rigidbodies |
| btJacobianEntry( |
| const btMatrix3x3& world2A, |
| const btMatrix3x3& world2B, |
| const btVector3& rel_pos1,const btVector3& rel_pos2, |
| const btVector3& jointAxis, |
| const btVector3& inertiaInvA, |
| const btScalar massInvA, |
| const btVector3& inertiaInvB, |
| const btScalar massInvB) |
| :m_linearJointAxis(jointAxis) |
| { |
| m_aJ = world2A*(rel_pos1.cross(m_linearJointAxis)); |
| m_bJ = world2B*(rel_pos2.cross(-m_linearJointAxis)); |
| m_0MinvJt = inertiaInvA * m_aJ; |
| m_1MinvJt = inertiaInvB * m_bJ; |
| m_Adiag = massInvA + m_0MinvJt.dot(m_aJ) + massInvB + m_1MinvJt.dot(m_bJ); |
| |
| btAssert(m_Adiag > btScalar(0.0)); |
| } |
| |
| //angular constraint between two different rigidbodies |
| btJacobianEntry(const btVector3& jointAxis, |
| const btMatrix3x3& world2A, |
| const btMatrix3x3& world2B, |
| const btVector3& inertiaInvA, |
| const btVector3& inertiaInvB) |
| :m_linearJointAxis(btVector3(btScalar(0.),btScalar(0.),btScalar(0.))) |
| { |
| m_aJ= world2A*jointAxis; |
| m_bJ = world2B*-jointAxis; |
| m_0MinvJt = inertiaInvA * m_aJ; |
| m_1MinvJt = inertiaInvB * m_bJ; |
| m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ); |
| |
| btAssert(m_Adiag > btScalar(0.0)); |
| } |
| |
| //angular constraint between two different rigidbodies |
| btJacobianEntry(const btVector3& axisInA, |
| const btVector3& axisInB, |
| const btVector3& inertiaInvA, |
| const btVector3& inertiaInvB) |
| : m_linearJointAxis(btVector3(btScalar(0.),btScalar(0.),btScalar(0.))) |
| , m_aJ(axisInA) |
| , m_bJ(-axisInB) |
| { |
| m_0MinvJt = inertiaInvA * m_aJ; |
| m_1MinvJt = inertiaInvB * m_bJ; |
| m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ); |
| |
| btAssert(m_Adiag > btScalar(0.0)); |
| } |
| |
| //constraint on one rigidbody |
| btJacobianEntry( |
| const btMatrix3x3& world2A, |
| const btVector3& rel_pos1,const btVector3& rel_pos2, |
| const btVector3& jointAxis, |
| const btVector3& inertiaInvA, |
| const btScalar massInvA) |
| :m_linearJointAxis(jointAxis) |
| { |
| m_aJ= world2A*(rel_pos1.cross(jointAxis)); |
| m_bJ = world2A*(rel_pos2.cross(-jointAxis)); |
| m_0MinvJt = inertiaInvA * m_aJ; |
| m_1MinvJt = btVector3(btScalar(0.),btScalar(0.),btScalar(0.)); |
| m_Adiag = massInvA + m_0MinvJt.dot(m_aJ); |
| |
| btAssert(m_Adiag > btScalar(0.0)); |
| } |
| |
| btScalar getDiagonal() const { return m_Adiag; } |
| |
| // for two constraints on the same rigidbody (for example vehicle friction) |
| btScalar getNonDiagonal(const btJacobianEntry& jacB, const btScalar massInvA) const |
| { |
| const btJacobianEntry& jacA = *this; |
| btScalar lin = massInvA * jacA.m_linearJointAxis.dot(jacB.m_linearJointAxis); |
| btScalar ang = jacA.m_0MinvJt.dot(jacB.m_aJ); |
| return lin + ang; |
| } |
| |
| |
| |
| // for two constraints on sharing two same rigidbodies (for example two contact points between two rigidbodies) |
| btScalar getNonDiagonal(const btJacobianEntry& jacB,const btScalar massInvA,const btScalar massInvB) const |
| { |
| const btJacobianEntry& jacA = *this; |
| btVector3 lin = jacA.m_linearJointAxis * jacB.m_linearJointAxis; |
| btVector3 ang0 = jacA.m_0MinvJt * jacB.m_aJ; |
| btVector3 ang1 = jacA.m_1MinvJt * jacB.m_bJ; |
| btVector3 lin0 = massInvA * lin ; |
| btVector3 lin1 = massInvB * lin; |
| btVector3 sum = ang0+ang1+lin0+lin1; |
| return sum[0]+sum[1]+sum[2]; |
| } |
| |
| btScalar getRelativeVelocity(const btVector3& linvelA,const btVector3& angvelA,const btVector3& linvelB,const btVector3& angvelB) |
| { |
| btVector3 linrel = linvelA - linvelB; |
| btVector3 angvela = angvelA * m_aJ; |
| btVector3 angvelb = angvelB * m_bJ; |
| linrel *= m_linearJointAxis; |
| angvela += angvelb; |
| angvela += linrel; |
| btScalar rel_vel2 = angvela[0]+angvela[1]+angvela[2]; |
| return rel_vel2 + SIMD_EPSILON; |
| } |
| //private: |
| |
| btVector3 m_linearJointAxis; |
| btVector3 m_aJ; |
| btVector3 m_bJ; |
| btVector3 m_0MinvJt; |
| btVector3 m_1MinvJt; |
| //Optimization: can be stored in the w/last component of one of the vectors |
| btScalar m_Adiag; |
| |
| }; |
| |
| #endif //JACOBIAN_ENTRY_H |