Bullet Collision Detection & Physics Library
btMultiBodyConstraint.h
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1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2013 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 
16 #ifndef BT_MULTIBODY_CONSTRAINT_H
17 #define BT_MULTIBODY_CONSTRAINT_H
18 
19 #include "LinearMath/btScalar.h"
21 #include "btMultiBody.h"
22 
23 class btMultiBody;
24 struct btSolverInfo;
25 
27 
29 {
31  btAlignedObjectArray<btScalar> m_deltaVelocitiesUnitImpulse; //holds the joint-space response of the corresp. tree to the test impulse in each constraint space dimension
32  btAlignedObjectArray<btScalar> m_deltaVelocities; //holds joint-space vectors of all the constrained trees accumulating the effect of corrective impulses applied in SI
38 
39 };
40 
41 
43 {
44 protected:
45 
48  int m_linkA;
49  int m_linkB;
50 
51  int m_numRows;
55 
57 
59 
60 
61  // data block laid out as follows:
62  // cached impulses. (one per row.)
63  // jacobians. (interleaved, row1 body1 then row1 body2 then row2 body 1 etc)
64  // positions. (one per row.)
66 
67  void applyDeltaVee(btMultiBodyJacobianData& data, btScalar* delta_vee, btScalar impulse, int velocityIndex, int ndof);
68 
69  btScalar fillMultiBodyConstraint(btMultiBodySolverConstraint& solverConstraint,
71  btScalar* jacOrgA, btScalar* jacOrgB,
72  const btVector3& contactNormalOnB,
73  const btVector3& posAworld, const btVector3& posBworld,
74  btScalar posError,
75  const btContactSolverInfo& infoGlobal,
76  btScalar lowerLimit, btScalar upperLimit,
77  btScalar relaxation = 1.f,
78  bool isFriction = false, btScalar desiredVelocity=0, btScalar cfmSlip=0);
79 
80 public:
81 
82  btMultiBodyConstraint(btMultiBody* bodyA,btMultiBody* bodyB,int linkA, int linkB, int numRows, bool isUnilateral);
83  virtual ~btMultiBodyConstraint();
84 
85  void finalizeMultiDof();
86 
87  virtual int getIslandIdA() const =0;
88  virtual int getIslandIdB() const =0;
89 
90  virtual void createConstraintRows(btMultiBodyConstraintArray& constraintRows,
92  const btContactSolverInfo& infoGlobal)=0;
93 
94  int getNumRows() const
95  {
96  return m_numRows;
97  }
98 
100  {
101  return m_bodyA;
102  }
104  {
105  return m_bodyB;
106  }
107 
108  // current constraint position
109  // constraint is pos >= 0 for unilateral, or pos = 0 for bilateral
110  // NOTE: ignored position for friction rows.
111  btScalar getPosition(int row) const
112  {
113  return m_data[m_posOffset + row];
114  }
115 
116  void setPosition(int row, btScalar pos)
117  {
118  m_data[m_posOffset + row] = pos;
119  }
120 
121 
122  bool isUnilateral() const
123  {
124  return m_isUnilateral;
125  }
126 
127  // jacobian blocks.
128  // each of size 6 + num_links. (jacobian2 is null if no body2.)
129  // format: 3 'omega' coefficients, 3 'v' coefficients, then the 'qdot' coefficients.
130  btScalar* jacobianA(int row)
131  {
132  return &m_data[m_numRows + row * m_jacSizeBoth];
133  }
134  const btScalar* jacobianA(int row) const
135  {
136  return &m_data[m_numRows + (row * m_jacSizeBoth)];
137  }
138  btScalar* jacobianB(int row)
139  {
140  return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
141  }
142  const btScalar* jacobianB(int row) const
143  {
144  return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
145  }
146 
148  {
149  return m_maxAppliedImpulse;
150  }
152  {
153  m_maxAppliedImpulse = maxImp;
154  }
155 
156  virtual void debugDraw(class btIDebugDraw* drawer)=0;
157 
158 };
159 
160 #endif //BT_MULTIBODY_CONSTRAINT_H
161 
btScalar getMaxAppliedImpulse() const
btScalar * jacobianB(int row)
1D constraint along a normal axis between bodyA and bodyB. It can be combined to solve contact and fr...
btAlignedObjectArray< btScalar > scratch_r
btAlignedObjectArray< btScalar > m_deltaVelocities
btAlignedObjectArray< btSolverBody > * m_solverBodyPool
btScalar * jacobianA(int row)
btAlignedObjectArray< btMatrix3x3 > scratch_m
btAlignedObjectArray< btScalar > m_deltaVelocitiesUnitImpulse
btScalar getPosition(int row) const
The btIDebugDraw interface class allows hooking up a debug renderer to visually debug simulations...
Definition: btIDebugDraw.h:28
btAlignedObjectArray< btScalar > m_data
btAlignedObjectArray< btScalar > m_jacobians
const btScalar * jacobianA(int row) const
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:83
btAlignedObjectArray< btVector3 > scratch_v
void setPosition(int row, btScalar pos)
void setMaxAppliedImpulse(btScalar maxImp)
const btScalar * jacobianB(int row) const
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:278