Blender  V3.3
btMultiBodySphericalJointMotor.cpp
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2018 Erwin Coumans http://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 
17 
19 #include "btMultiBody.h"
24 
26  : btMultiBodyConstraint(body, body, link, body->getLink(link).m_parent, 3, true, MULTIBODY_CONSTRAINT_SPHERICAL_MOTOR),
27  m_desiredVelocity(0, 0, 0),
28  m_desiredPosition(0,0,0,1),
29  m_kd(1.),
30  m_kp(0.2),
31  m_erp(1),
32  m_rhsClamp(SIMD_INFINITY)
33 {
34 
35  m_maxAppliedImpulse = maxMotorImpulse;
36 }
37 
38 
40 {
42  // note: we rely on the fact that data.m_jacobians are
43  // always initialized to zero by the Constraint ctor
44  int linkDoF = 0;
45  unsigned int offset = 6 + (m_bodyA->getLink(m_linkA).m_dofOffset + linkDoF);
46 
47  // row 0: the lower bound
48  // row 0: the lower bound
49  jacobianA(0)[offset] = 1;
50 
52 }
53 
54 
56 {
57 }
58 
60 {
61  if (this->m_linkA < 0)
62  {
63  btMultiBodyLinkCollider* col = m_bodyA->getBaseCollider();
64  if (col)
65  return col->getIslandTag();
66  }
67  else
68  {
69  if (m_bodyA->getLink(m_linkA).m_collider)
70  {
71  return m_bodyA->getLink(m_linkA).m_collider->getIslandTag();
72  }
73  }
74  return -1;
75 }
76 
78 {
79  if (m_linkB < 0)
80  {
81  btMultiBodyLinkCollider* col = m_bodyB->getBaseCollider();
82  if (col)
83  return col->getIslandTag();
84  }
85  else
86  {
87  if (m_bodyB->getLink(m_linkB).m_collider)
88  {
89  return m_bodyB->getLink(m_linkB).m_collider->getIslandTag();
90  }
91  }
92  return -1;
93 }
94 
98 {
99  // only positions need to be updated -- data.m_jacobians and force
100  // directions were set in the ctor and never change.
101 
103  {
105  }
106 
107  //don't crash
109  return;
110 
111 
112  if (m_maxAppliedImpulse == 0.f)
113  return;
114 
115  const btScalar posError = 0;
116  const btVector3 dummy(0, 0, 0);
117 
118 
119  btVector3 axis[3] = { btVector3(1, 0, 0), btVector3(0, 1, 0), btVector3(0, 0, 1) };
120 
121  btQuaternion desiredQuat = m_desiredPosition;
122  btQuaternion currentQuat(m_bodyA->getJointPosMultiDof(m_linkA)[0],
123  m_bodyA->getJointPosMultiDof(m_linkA)[1],
124  m_bodyA->getJointPosMultiDof(m_linkA)[2],
125  m_bodyA->getJointPosMultiDof(m_linkA)[3]);
126 
127 btQuaternion relRot = currentQuat.inverse() * desiredQuat;
128  btVector3 angleDiff;
130 
131 
132 
133  for (int row = 0; row < getNumRows(); row++)
134  {
135  btMultiBodySolverConstraint& constraintRow = constraintRows.expandNonInitializing();
136 
137  int dof = row;
138 
139  btScalar currentVelocity = m_bodyA->getJointVelMultiDof(m_linkA)[dof];
140  btScalar desiredVelocity = this->m_desiredVelocity[row];
141 
142  btScalar velocityError = desiredVelocity - currentVelocity;
143 
144  btMatrix3x3 frameAworld;
145  frameAworld.setIdentity();
146  frameAworld = m_bodyA->localFrameToWorld(m_linkA, frameAworld);
147  btScalar posError = 0;
148  {
149  btAssert(m_bodyA->getLink(m_linkA).m_jointType == btMultibodyLink::eSpherical);
150  switch (m_bodyA->getLink(m_linkA).m_jointType)
151  {
153  {
154  btVector3 constraintNormalAng = frameAworld.getColumn(row % 3);
155  posError = m_kp*angleDiff[row % 3];
156  fillMultiBodyConstraint(constraintRow, data, 0, 0, constraintNormalAng,
157  btVector3(0,0,0), dummy, dummy,
158  posError,
159  infoGlobal,
161  constraintRow.m_orgConstraint = this;
162  constraintRow.m_orgDofIndex = row;
163  break;
164  }
165  default:
166  {
167  btAssert(0);
168  }
169  };
170  }
171  }
172 }
bool matrixToEulerXYZ(const btMatrix3x3 &mat, btVector3 &xyz)
MatrixToEulerXYZ from http://www.geometrictools.com/LibFoundation/Mathematics/Wm4Matrix3....
btMatrix3x3
The btMatrix3x3 class implements a 3x3 rotation matrix, to perform linear algebra in combination with...
Definition: btMatrix3x3.h:50
@ MULTIBODY_CONSTRAINT_SPHERICAL_MOTOR
int m_numDofsFinalized
int m_linkB
btMultiBody * m_bodyB
int m_linkA
void allocateJacobiansMultiDof()
int m_jacSizeBoth
btScalar fillMultiBodyConstraint(btMultiBodySolverConstraint &solverConstraint, btMultiBodyJacobianData &data, btScalar *jacOrgA, btScalar *jacOrgB, const btVector3 &constraintNormalAng, const btVector3 &constraintNormalLin, const btVector3 &posAworld, const btVector3 &posBworld, btScalar posError, const btContactSolverInfo &infoGlobal, btScalar lowerLimit, btScalar upperLimit, bool angConstraint=false, btScalar relaxation=1.f, bool isFriction=false, btScalar desiredVelocity=0, btScalar cfmSlip=0)
btScalar m_maxAppliedImpulse
btScalar * jacobianA(int row)
btMultiBodyConstraint
int getNumRows() const
btMultiBodySolverConstraint
1D constraint along a normal axis between bodyA and bodyB. It can be combined to solve contact and fr...
const btMultibodyLink & getLink(int index) const
Definition: btMultiBody.h:114
btMultiBody
Definition: btMultiBody.h:51
btScalar m_erp
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
#define SIMD_INFINITY
Definition: btScalar.h:544
#define btAssert(x)
Definition: btScalar.h:295
btSequentialImpulseConstraintSolverMt int btPersistentManifold int btTypedConstraint int const btContactSolverInfo & infoGlobal
btVector3
btVector3 can be used to represent 3D points and vectors. It has an un-used w component to suit 16-by...
Definition: btVector3.h:82
SIMD_FORCE_INLINE T & expandNonInitializing()
btMultiBodySphericalJointMotor(btMultiBody *body, int link, btScalar maxMotorImpulse)
This file was written by Erwin Coumans.
virtual void createConstraintRows(btMultiBodyConstraintArray &constraintRows, btMultiBodyJacobianData &data, const btContactSolverInfo &infoGlobal)
The btQuaternion implements quaternion to perform linear algebra rotations in combination with btMatr...
Definition: btQuaternion.h:50
btQuaternion inverse() const
Return the inverse of this quaternion.
Definition: btQuaternion.h:497
uint col
ccl_gpu_kernel_postfix ccl_global float int int int int float bool int offset