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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"
20 #include "LinearMath/btAlignedObjectArray.h"
21 #include "btMultiBody.h"
22 
23 class btMultiBody;
24 struct btSolverInfo;
25 
26 #include "btMultiBodySolverConstraint.h"
27 
28 struct btMultiBodyJacobianData
29 {
30 	btAlignedObjectArray<btScalar>		m_jacobians;
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
33 	btAlignedObjectArray<btScalar>		scratch_r;
34 	btAlignedObjectArray<btVector3>		scratch_v;
35 	btAlignedObjectArray<btMatrix3x3>	scratch_m;
36 	btAlignedObjectArray<btSolverBody>*	m_solverBodyPool;
37 	int									m_fixedBodyId;
38 
39 };
40 
41 
42 class btMultiBodyConstraint
43 {
44 protected:
45 
46 	btMultiBody*	m_bodyA;
47     btMultiBody*	m_bodyB;
48     int				m_linkA;
49     int				m_linkB;
50 
51     int				m_numRows;
52     int				m_jacSizeA;
53     int				m_jacSizeBoth;
54     int				m_posOffset;
55 
56 	bool			m_isUnilateral;
57 	int				m_numDofsFinalized;
58 	btScalar		m_maxAppliedImpulse;
59 
60 
61     // warning: the data block lay out is not consistent for all constraints
62     // data block laid out as follows:
63     // cached impulses. (one per row.)
64     // jacobians. (interleaved, row1 body1 then row1 body2 then row2 body 1 etc)
65     // positions. (one per row.)
66     btAlignedObjectArray<btScalar> m_data;
67 
68 	void	applyDeltaVee(btMultiBodyJacobianData& data, btScalar* delta_vee, btScalar impulse, int velocityIndex, int ndof);
69 
70 	btScalar fillMultiBodyConstraint(btMultiBodySolverConstraint& solverConstraint,
71 																btMultiBodyJacobianData& data,
72 																btScalar* jacOrgA, btScalar* jacOrgB,
73 																const btVector3& contactNormalOnB,
74 																const btVector3& posAworld, const btVector3& posBworld,
75 																btScalar posError,
76 																const btContactSolverInfo& infoGlobal,
77 																btScalar lowerLimit, btScalar upperLimit,
78 																btScalar relaxation = 1.f,
79 																bool isFriction = false, btScalar desiredVelocity=0, btScalar cfmSlip=0);
80 
81 public:
82 
83 	btMultiBodyConstraint(btMultiBody* bodyA,btMultiBody* bodyB,int linkA, int linkB, int numRows, bool isUnilateral);
84 	virtual ~btMultiBodyConstraint();
85 
86 	void updateJacobianSizes();
87 	void allocateJacobiansMultiDof();
88 
89 	virtual void finalizeMultiDof()=0;
90 
91 	virtual int getIslandIdA() const =0;
92 	virtual int getIslandIdB() const =0;
93 
94 	virtual void createConstraintRows(btMultiBodyConstraintArray& constraintRows,
95 		btMultiBodyJacobianData& data,
96 		const btContactSolverInfo& infoGlobal)=0;
97 
getNumRows()98 	int	getNumRows() const
99 	{
100 		return m_numRows;
101 	}
102 
getMultiBodyA()103 	btMultiBody*	getMultiBodyA()
104 	{
105 		return m_bodyA;
106 	}
getMultiBodyB()107     btMultiBody*	getMultiBodyB()
108 	{
109 		return m_bodyB;
110 	}
111 
internalSetAppliedImpulse(int dof,btScalar appliedImpulse)112 	void	internalSetAppliedImpulse(int dof, btScalar appliedImpulse)
113 	{
114 		btAssert(dof>=0);
115 		btAssert(dof < getNumRows());
116 		m_data[dof] = appliedImpulse;
117 	}
118 
getAppliedImpulse(int dof)119 	btScalar	getAppliedImpulse(int dof)
120 	{
121 		btAssert(dof>=0);
122 		btAssert(dof < getNumRows());
123 		return m_data[dof];
124 	}
125 	// current constraint position
126     // constraint is pos >= 0 for unilateral, or pos = 0 for bilateral
127     // NOTE: ignored position for friction rows.
getPosition(int row)128     btScalar getPosition(int row) const
129 	{
130 		return m_data[m_posOffset + row];
131 	}
132 
setPosition(int row,btScalar pos)133     void setPosition(int row, btScalar pos)
134 	{
135 		m_data[m_posOffset + row] = pos;
136 	}
137 
138 
isUnilateral()139 	bool isUnilateral() const
140 	{
141 		return m_isUnilateral;
142 	}
143 
144 	// jacobian blocks.
145     // each of size 6 + num_links. (jacobian2 is null if no body2.)
146     // format: 3 'omega' coefficients, 3 'v' coefficients, then the 'qdot' coefficients.
jacobianA(int row)147     btScalar* jacobianA(int row)
148 	{
149 		return &m_data[m_numRows + row * m_jacSizeBoth];
150 	}
jacobianA(int row)151     const btScalar* jacobianA(int row) const
152 	{
153 		return &m_data[m_numRows + (row * m_jacSizeBoth)];
154 	}
jacobianB(int row)155     btScalar* jacobianB(int row)
156 	{
157 		return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
158 	}
jacobianB(int row)159     const btScalar* jacobianB(int row) const
160 	{
161 		return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
162 	}
163 
getMaxAppliedImpulse()164 	btScalar	getMaxAppliedImpulse() const
165 	{
166 		return m_maxAppliedImpulse;
167 	}
setMaxAppliedImpulse(btScalar maxImp)168 	void	setMaxAppliedImpulse(btScalar maxImp)
169 	{
170 		m_maxAppliedImpulse = maxImp;
171 	}
172 
173 	virtual void debugDraw(class btIDebugDraw* drawer)=0;
174 
175 };
176 
177 #endif //BT_MULTIBODY_CONSTRAINT_H
178 
179