dali-physics/third-party/bullet3/src/Bullet3Dynamics/ConstraintSolver/b3JacobianEntry.h

   1 /*
   2 Bullet Continuous Collision Detection and Physics Library
   3 Copyright (c) 2003-2006 Erwin Coumans  https://bulletphysics.org
   4
   5 This software is provided 'as-is', without any express or implied warranty.
   6 In no event will the authors be held liable for any damages arising from the use of this software.
   7 Permission is granted to anyone to use this software for any purpose,
   8 including commercial applications, and to alter it and redistribute it freely,
   9 subject to the following restrictions:
  10
  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.
  12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
  13 3. This notice may not be removed or altered from any source distribution.
  14 */
  15
  16 #ifndef B3_JACOBIAN_ENTRY_H
  17 #define B3_JACOBIAN_ENTRY_H
  18
  19 #include "Bullet3Common/b3Matrix3x3.h"
  20
  21 //notes:
  22 // Another memory optimization would be to store m_1MinvJt in the remaining 3 w components
  23 // which makes the b3JacobianEntry memory layout 16 bytes
  24 // if you only are interested in angular part, just feed massInvA and massInvB zero
  25
  26 /// Jacobian entry is an abstraction that allows to describe constraints
  27 /// it can be used in combination with a constraint solver
  28 /// Can be used to relate the effect of an impulse to the constraint error
  29 B3_ATTRIBUTE_ALIGNED16(class)
  30 b3JacobianEntry
  31 {
  32 public:
  33         b3JacobianEntry(){};
  34         //constraint between two different rigidbodies
  35         b3JacobianEntry(
  36                 const b3Matrix3x3& world2A,
  37                 const b3Matrix3x3& world2B,
  38                 const b3Vector3& rel_pos1, const b3Vector3& rel_pos2,
  39                 const b3Vector3& jointAxis,
  40                 const b3Vector3& inertiaInvA,
  41                 const b3Scalar massInvA,
  42                 const b3Vector3& inertiaInvB,
  43                 const b3Scalar massInvB)
  44                 : m_linearJointAxis(jointAxis)
  45         {
  46                 m_aJ = world2A * (rel_pos1.cross(m_linearJointAxis));
  47                 m_bJ = world2B * (rel_pos2.cross(-m_linearJointAxis));
  48                 m_0MinvJt = inertiaInvA * m_aJ;
  49                 m_1MinvJt = inertiaInvB * m_bJ;
  50                 m_Adiag = massInvA + m_0MinvJt.dot(m_aJ) + massInvB + m_1MinvJt.dot(m_bJ);
  51
  52                 b3Assert(m_Adiag > b3Scalar(0.0));
  53         }
  54
  55         //angular constraint between two different rigidbodies
  56         b3JacobianEntry(const b3Vector3& jointAxis,
  57                                         const b3Matrix3x3& world2A,
  58                                         const b3Matrix3x3& world2B,
  59                                         const b3Vector3& inertiaInvA,
  60                                         const b3Vector3& inertiaInvB)
  61                 : m_linearJointAxis(b3MakeVector3(b3Scalar(0.), b3Scalar(0.), b3Scalar(0.)))
  62         {
  63                 m_aJ = world2A * jointAxis;
  64                 m_bJ = world2B * -jointAxis;
  65                 m_0MinvJt = inertiaInvA * m_aJ;
  66                 m_1MinvJt = inertiaInvB * m_bJ;
  67                 m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ);
  68
  69                 b3Assert(m_Adiag > b3Scalar(0.0));
  70         }
  71
  72         //angular constraint between two different rigidbodies
  73         b3JacobianEntry(const b3Vector3& axisInA,
  74                                         const b3Vector3& axisInB,
  75                                         const b3Vector3& inertiaInvA,
  76                                         const b3Vector3& inertiaInvB)
  77                 : m_linearJointAxis(b3MakeVector3(b3Scalar(0.), b3Scalar(0.), b3Scalar(0.))), m_aJ(axisInA), m_bJ(-axisInB)
  78         {
  79                 m_0MinvJt = inertiaInvA * m_aJ;
  80                 m_1MinvJt = inertiaInvB * m_bJ;
  81                 m_Adiag = m_0MinvJt.dot(m_aJ) + m_1MinvJt.dot(m_bJ);
  82
  83                 b3Assert(m_Adiag > b3Scalar(0.0));
  84         }
  85
  86         //constraint on one rigidbody
  87         b3JacobianEntry(
  88                 const b3Matrix3x3& world2A,
  89                 const b3Vector3& rel_pos1, const b3Vector3& rel_pos2,
  90                 const b3Vector3& jointAxis,
  91                 const b3Vector3& inertiaInvA,
  92                 const b3Scalar massInvA)
  93                 : m_linearJointAxis(jointAxis)
  94         {
  95                 m_aJ = world2A * (rel_pos1.cross(jointAxis));
  96                 m_bJ = world2A * (rel_pos2.cross(-jointAxis));
  97                 m_0MinvJt = inertiaInvA * m_aJ;
  98                 m_1MinvJt = b3MakeVector3(b3Scalar(0.), b3Scalar(0.), b3Scalar(0.));
  99                 m_Adiag = massInvA + m_0MinvJt.dot(m_aJ);
 100
 101                 b3Assert(m_Adiag > b3Scalar(0.0));
 102         }
 103
 104         b3Scalar getDiagonal() const { return m_Adiag; }
 105
 106         // for two constraints on the same rigidbody (for example vehicle friction)
 107         b3Scalar getNonDiagonal(const b3JacobianEntry& jacB, const b3Scalar massInvA) const
 108         {
 109                 const b3JacobianEntry& jacA = *this;
 110                 b3Scalar lin = massInvA * jacA.m_linearJointAxis.dot(jacB.m_linearJointAxis);
 111                 b3Scalar ang = jacA.m_0MinvJt.dot(jacB.m_aJ);
 112                 return lin + ang;
 113         }
 114
 115         // for two constraints on sharing two same rigidbodies (for example two contact points between two rigidbodies)
 116         b3Scalar getNonDiagonal(const b3JacobianEntry& jacB, const b3Scalar massInvA, const b3Scalar massInvB) const
 117         {
 118                 const b3JacobianEntry& jacA = *this;
 119                 b3Vector3 lin = jacA.m_linearJointAxis * jacB.m_linearJointAxis;
 120                 b3Vector3 ang0 = jacA.m_0MinvJt * jacB.m_aJ;
 121                 b3Vector3 ang1 = jacA.m_1MinvJt * jacB.m_bJ;
 122                 b3Vector3 lin0 = massInvA * lin;
 123                 b3Vector3 lin1 = massInvB * lin;
 124                 b3Vector3 sum = ang0 + ang1 + lin0 + lin1;
 125                 return sum[0] + sum[1] + sum[2];
 126         }
 127
 128         b3Scalar getRelativeVelocity(const b3Vector3& linvelA, const b3Vector3& angvelA, const b3Vector3& linvelB, const b3Vector3& angvelB)
 129         {
 130                 b3Vector3 linrel = linvelA - linvelB;
 131                 b3Vector3 angvela = angvelA * m_aJ;
 132                 b3Vector3 angvelb = angvelB * m_bJ;
 133                 linrel *= m_linearJointAxis;
 134                 angvela += angvelb;
 135                 angvela += linrel;
 136                 b3Scalar rel_vel2 = angvela[0] + angvela[1] + angvela[2];
 137                 return rel_vel2 + B3_EPSILON;
 138         }
 139         //private:
 140
 141         b3Vector3 m_linearJointAxis;
 142         b3Vector3 m_aJ;
 143         b3Vector3 m_bJ;
 144         b3Vector3 m_0MinvJt;
 145         b3Vector3 m_1MinvJt;
 146         //Optimization: can be stored in the w/last component of one of the vectors
 147         b3Scalar m_Adiag;
 148 };
 149
 150 #endif  //B3_JACOBIAN_ENTRY_H