[1963] | 1 | /* |
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| 2 | Bullet Continuous Collision Detection and Physics Library |
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| 3 | Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/ |
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| 4 | |
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| 5 | This software is provided 'as-is', without any express or implied warranty. |
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| 6 | In no event will the authors be held liable for any damages arising from the use of this software. |
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| 7 | Permission is granted to anyone to use this software for any purpose, |
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| 8 | including commercial applications, and to alter it and redistribute it freely, |
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| 9 | subject to the following restrictions: |
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| 10 | |
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| 11 | 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. |
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| 12 | 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. |
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| 13 | 3. This notice may not be removed or altered from any source distribution. |
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| 14 | */ |
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| 15 | |
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| 16 | #ifndef JACOBIAN_ENTRY_H |
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| 17 | #define JACOBIAN_ENTRY_H |
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| 18 | |
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| 19 | #include "LinearMath/btVector3.h" |
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| 20 | #include "BulletDynamics/Dynamics/btRigidBody.h" |
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| 21 | |
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| 22 | |
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| 23 | //notes: |
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| 24 | // Another memory optimization would be to store m_1MinvJt in the remaining 3 w components |
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| 25 | // which makes the btJacobianEntry memory layout 16 bytes |
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| 26 | // if you only are interested in angular part, just feed massInvA and massInvB zero |
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| 27 | |
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| 28 | /// Jacobian entry is an abstraction that allows to describe constraints |
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| 29 | /// it can be used in combination with a constraint solver |
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| 30 | /// Can be used to relate the effect of an impulse to the constraint error |
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[7983] | 31 | ATTRIBUTE_ALIGNED16(class) btJacobianEntry |
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[1963] | 32 | { |
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| 33 | public: |
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| 34 | btJacobianEntry() {}; |
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| 35 | //constraint between two different rigidbodies |
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| 36 | btJacobianEntry( |
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| 37 | const btMatrix3x3& world2A, |
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| 38 | const btMatrix3x3& world2B, |
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| 39 | const btVector3& rel_pos1,const btVector3& rel_pos2, |
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| 40 | const btVector3& jointAxis, |
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| 41 | const btVector3& inertiaInvA, |
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| 42 | const btScalar massInvA, |
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| 43 | const btVector3& inertiaInvB, |
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| 44 | const btScalar massInvB) |
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| 45 | :m_linearJointAxis(jointAxis) |
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| 46 | { |
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| 47 | m_aJ = world2A*(rel_pos1.cross(m_linearJointAxis)); |
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| 48 | m_bJ = world2B*(rel_pos2.cross(-m_linearJointAxis)); |
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| 49 | m_0MinvJt = inertiaInvA * m_aJ; |
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| 50 | m_1MinvJt = inertiaInvB * m_bJ; |
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| 51 | m_Adiag = massInvA + m_0MinvJt.dot(m_aJ) + massInvB + m_1MinvJt.dot(m_bJ); |
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| 52 | |
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| 53 | btAssert(m_Adiag > btScalar(0.0)); |
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| 54 | } |
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| 55 | |
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| 56 | //angular constraint between two different rigidbodies |
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| 57 | btJacobianEntry(const btVector3& jointAxis, |
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| 58 | const btMatrix3x3& world2A, |
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| 59 | const btMatrix3x3& world2B, |
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| 60 | const btVector3& inertiaInvA, |
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| 61 | const btVector3& inertiaInvB) |
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| 62 | :m_linearJointAxis(btVector3(btScalar(0.),btScalar(0.),btScalar(0.))) |
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| 63 | { |
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| 64 | m_aJ= world2A*jointAxis; |
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| 65 | m_bJ = world2B*-jointAxis; |
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| 66 | m_0MinvJt = inertiaInvA * m_aJ; |
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| 67 | m_1MinvJt = inertiaInvB * m_bJ; |
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| 68 | m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ); |
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| 69 | |
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| 70 | btAssert(m_Adiag > btScalar(0.0)); |
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| 71 | } |
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| 72 | |
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| 73 | //angular constraint between two different rigidbodies |
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| 74 | btJacobianEntry(const btVector3& axisInA, |
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| 75 | const btVector3& axisInB, |
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| 76 | const btVector3& inertiaInvA, |
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| 77 | const btVector3& inertiaInvB) |
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| 78 | : m_linearJointAxis(btVector3(btScalar(0.),btScalar(0.),btScalar(0.))) |
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| 79 | , m_aJ(axisInA) |
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| 80 | , m_bJ(-axisInB) |
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| 81 | { |
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| 82 | m_0MinvJt = inertiaInvA * m_aJ; |
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| 83 | m_1MinvJt = inertiaInvB * m_bJ; |
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| 84 | m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ); |
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| 85 | |
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| 86 | btAssert(m_Adiag > btScalar(0.0)); |
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| 87 | } |
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| 88 | |
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| 89 | //constraint on one rigidbody |
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| 90 | btJacobianEntry( |
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| 91 | const btMatrix3x3& world2A, |
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| 92 | const btVector3& rel_pos1,const btVector3& rel_pos2, |
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| 93 | const btVector3& jointAxis, |
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| 94 | const btVector3& inertiaInvA, |
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| 95 | const btScalar massInvA) |
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| 96 | :m_linearJointAxis(jointAxis) |
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| 97 | { |
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| 98 | m_aJ= world2A*(rel_pos1.cross(jointAxis)); |
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| 99 | m_bJ = world2A*(rel_pos2.cross(-jointAxis)); |
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| 100 | m_0MinvJt = inertiaInvA * m_aJ; |
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| 101 | m_1MinvJt = btVector3(btScalar(0.),btScalar(0.),btScalar(0.)); |
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| 102 | m_Adiag = massInvA + m_0MinvJt.dot(m_aJ); |
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| 103 | |
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| 104 | btAssert(m_Adiag > btScalar(0.0)); |
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| 105 | } |
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| 106 | |
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| 107 | btScalar getDiagonal() const { return m_Adiag; } |
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| 108 | |
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| 109 | // for two constraints on the same rigidbody (for example vehicle friction) |
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| 110 | btScalar getNonDiagonal(const btJacobianEntry& jacB, const btScalar massInvA) const |
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| 111 | { |
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| 112 | const btJacobianEntry& jacA = *this; |
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| 113 | btScalar lin = massInvA * jacA.m_linearJointAxis.dot(jacB.m_linearJointAxis); |
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| 114 | btScalar ang = jacA.m_0MinvJt.dot(jacB.m_aJ); |
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| 115 | return lin + ang; |
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| 116 | } |
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| 117 | |
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| 118 | |
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| 119 | |
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| 120 | // for two constraints on sharing two same rigidbodies (for example two contact points between two rigidbodies) |
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| 121 | btScalar getNonDiagonal(const btJacobianEntry& jacB,const btScalar massInvA,const btScalar massInvB) const |
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| 122 | { |
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| 123 | const btJacobianEntry& jacA = *this; |
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| 124 | btVector3 lin = jacA.m_linearJointAxis * jacB.m_linearJointAxis; |
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| 125 | btVector3 ang0 = jacA.m_0MinvJt * jacB.m_aJ; |
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| 126 | btVector3 ang1 = jacA.m_1MinvJt * jacB.m_bJ; |
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| 127 | btVector3 lin0 = massInvA * lin ; |
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| 128 | btVector3 lin1 = massInvB * lin; |
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| 129 | btVector3 sum = ang0+ang1+lin0+lin1; |
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| 130 | return sum[0]+sum[1]+sum[2]; |
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| 131 | } |
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| 132 | |
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| 133 | btScalar getRelativeVelocity(const btVector3& linvelA,const btVector3& angvelA,const btVector3& linvelB,const btVector3& angvelB) |
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| 134 | { |
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| 135 | btVector3 linrel = linvelA - linvelB; |
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| 136 | btVector3 angvela = angvelA * m_aJ; |
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| 137 | btVector3 angvelb = angvelB * m_bJ; |
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| 138 | linrel *= m_linearJointAxis; |
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| 139 | angvela += angvelb; |
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| 140 | angvela += linrel; |
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| 141 | btScalar rel_vel2 = angvela[0]+angvela[1]+angvela[2]; |
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| 142 | return rel_vel2 + SIMD_EPSILON; |
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| 143 | } |
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| 144 | //private: |
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| 145 | |
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| 146 | btVector3 m_linearJointAxis; |
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| 147 | btVector3 m_aJ; |
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| 148 | btVector3 m_bJ; |
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| 149 | btVector3 m_0MinvJt; |
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| 150 | btVector3 m_1MinvJt; |
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| 151 | //Optimization: can be stored in the w/last component of one of the vectors |
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| 152 | btScalar m_Adiag; |
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| 153 | |
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| 154 | }; |
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| 155 | |
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| 156 | #endif //JACOBIAN_ENTRY_H |
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