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 
58 	btScalar		m_maxAppliedImpulse;
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.)
65     btAlignedObjectArray<btScalar> m_data;
66 
67 	void	applyDeltaVee(btMultiBodyJacobianData& data, btScalar* delta_vee, btScalar impulse, int velocityIndex, int ndof);
68 
69 	btScalar fillMultiBodyConstraint(btMultiBodySolverConstraint& solverConstraint,
70 																btMultiBodyJacobianData& data,
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,
91 		btMultiBodyJacobianData& data,
92 		const btContactSolverInfo& infoGlobal)=0;
93 
getNumRows()94 	int	getNumRows() const
95 	{
96 		return m_numRows;
97 	}
98 
getMultiBodyA()99 	btMultiBody*	getMultiBodyA()
100 	{
101 		return m_bodyA;
102 	}
getMultiBodyB()103     btMultiBody*	getMultiBodyB()
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.
getPosition(int row)111     btScalar getPosition(int row) const
112 	{
113 		return m_data[m_posOffset + row];
114 	}
115 
setPosition(int row,btScalar pos)116     void setPosition(int row, btScalar pos)
117 	{
118 		m_data[m_posOffset + row] = pos;
119 	}
120 
121 
isUnilateral()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.
jacobianA(int row)130     btScalar* jacobianA(int row)
131 	{
132 		return &m_data[m_numRows + row * m_jacSizeBoth];
133 	}
jacobianA(int row)134     const btScalar* jacobianA(int row) const
135 	{
136 		return &m_data[m_numRows + (row * m_jacSizeBoth)];
137 	}
jacobianB(int row)138     btScalar* jacobianB(int row)
139 	{
140 		return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
141 	}
jacobianB(int row)142     const btScalar* jacobianB(int row) const
143 	{
144 		return &m_data[m_numRows + (row * m_jacSizeBoth) + m_jacSizeA];
145 	}
146 
getMaxAppliedImpulse()147 	btScalar	getMaxAppliedImpulse() const
148 	{
149 		return m_maxAppliedImpulse;
150 	}
setMaxAppliedImpulse(btScalar maxImp)151 	void	setMaxAppliedImpulse(btScalar maxImp)
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 
162