1 /*
2 Bullet Continuous Collision Detection and Physics Library
3 Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/
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 #include "btPoint2PointConstraint.h"
17 #include "BulletDynamics/Dynamics/btRigidBody.h"
18 #include <new>
19 
btPoint2PointConstraint(btRigidBody & rbA,btRigidBody & rbB,const btVector3 & pivotInA,const btVector3 & pivotInB)20 btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA, btRigidBody& rbB, const btVector3& pivotInA, const btVector3& pivotInB)
21 	: btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE, rbA, rbB), m_pivotInA(pivotInA), m_pivotInB(pivotInB), m_flags(0), m_useSolveConstraintObsolete(false)
22 {
23 }
24 
btPoint2PointConstraint(btRigidBody & rbA,const btVector3 & pivotInA)25 btPoint2PointConstraint::btPoint2PointConstraint(btRigidBody& rbA, const btVector3& pivotInA)
26 	: btTypedConstraint(POINT2POINT_CONSTRAINT_TYPE, rbA), m_pivotInA(pivotInA), m_pivotInB(rbA.getCenterOfMassTransform()(pivotInA)), m_flags(0), m_useSolveConstraintObsolete(false)
27 {
28 }
29 
buildJacobian()30 void btPoint2PointConstraint::buildJacobian()
31 {
32 	///we need it for both methods
33 	{
34 		m_appliedImpulse = btScalar(0.);
35 
36 		btVector3 normal(0, 0, 0);
37 
38 		for (int i = 0; i < 3; i++)
39 		{
40 			normal[i] = 1;
41 			new (&m_jac[i]) btJacobianEntry(
42 				m_rbA.getCenterOfMassTransform().getBasis().transpose(),
43 				m_rbB.getCenterOfMassTransform().getBasis().transpose(),
44 				m_rbA.getCenterOfMassTransform() * m_pivotInA - m_rbA.getCenterOfMassPosition(),
45 				m_rbB.getCenterOfMassTransform() * m_pivotInB - m_rbB.getCenterOfMassPosition(),
46 				normal,
47 				m_rbA.getInvInertiaDiagLocal(),
48 				m_rbA.getInvMass(),
49 				m_rbB.getInvInertiaDiagLocal(),
50 				m_rbB.getInvMass());
51 			normal[i] = 0;
52 		}
53 	}
54 }
55 
getInfo1(btConstraintInfo1 * info)56 void btPoint2PointConstraint::getInfo1(btConstraintInfo1* info)
57 {
58 	getInfo1NonVirtual(info);
59 }
60 
getInfo1NonVirtual(btConstraintInfo1 * info)61 void btPoint2PointConstraint::getInfo1NonVirtual(btConstraintInfo1* info)
62 {
63 	if (m_useSolveConstraintObsolete)
64 	{
65 		info->m_numConstraintRows = 0;
66 		info->nub = 0;
67 	}
68 	else
69 	{
70 		info->m_numConstraintRows = 3;
71 		info->nub = 3;
72 	}
73 }
74 
getInfo2(btConstraintInfo2 * info)75 void btPoint2PointConstraint::getInfo2(btConstraintInfo2* info)
76 {
77 	getInfo2NonVirtual(info, m_rbA.getCenterOfMassTransform(), m_rbB.getCenterOfMassTransform());
78 }
79 
getInfo2NonVirtual(btConstraintInfo2 * info,const btTransform & body0_trans,const btTransform & body1_trans)80 void btPoint2PointConstraint::getInfo2NonVirtual(btConstraintInfo2* info, const btTransform& body0_trans, const btTransform& body1_trans)
81 {
82 	btAssert(!m_useSolveConstraintObsolete);
83 
84 	//retrieve matrices
85 
86 	// anchor points in global coordinates with respect to body PORs.
87 
88 	// set jacobian
89 	info->m_J1linearAxis[0] = 1;
90 	info->m_J1linearAxis[info->rowskip + 1] = 1;
91 	info->m_J1linearAxis[2 * info->rowskip + 2] = 1;
92 
93 	btVector3 a1 = body0_trans.getBasis() * getPivotInA();
94 	{
95 		btVector3* angular0 = (btVector3*)(info->m_J1angularAxis);
96 		btVector3* angular1 = (btVector3*)(info->m_J1angularAxis + info->rowskip);
97 		btVector3* angular2 = (btVector3*)(info->m_J1angularAxis + 2 * info->rowskip);
98 		btVector3 a1neg = -a1;
99 		a1neg.getSkewSymmetricMatrix(angular0, angular1, angular2);
100 	}
101 
102 	info->m_J2linearAxis[0] = -1;
103 	info->m_J2linearAxis[info->rowskip + 1] = -1;
104 	info->m_J2linearAxis[2 * info->rowskip + 2] = -1;
105 
106 	btVector3 a2 = body1_trans.getBasis() * getPivotInB();
107 
108 	{
109 		//	btVector3 a2n = -a2;
110 		btVector3* angular0 = (btVector3*)(info->m_J2angularAxis);
111 		btVector3* angular1 = (btVector3*)(info->m_J2angularAxis + info->rowskip);
112 		btVector3* angular2 = (btVector3*)(info->m_J2angularAxis + 2 * info->rowskip);
113 		a2.getSkewSymmetricMatrix(angular0, angular1, angular2);
114 	}
115 
116 	// set right hand side
117 	btScalar currERP = (m_flags & BT_P2P_FLAGS_ERP) ? m_erp : info->erp;
118 	btScalar k = info->fps * currERP;
119 	int j;
120 	for (j = 0; j < 3; j++)
121 	{
122 		info->m_constraintError[j * info->rowskip] = k * (a2[j] + body1_trans.getOrigin()[j] - a1[j] - body0_trans.getOrigin()[j]);
123 		//printf("info->m_constraintError[%d]=%f\n",j,info->m_constraintError[j]);
124 	}
125 	if (m_flags & BT_P2P_FLAGS_CFM)
126 	{
127 		for (j = 0; j < 3; j++)
128 		{
129 			info->cfm[j * info->rowskip] = m_cfm;
130 		}
131 	}
132 
133 	btScalar impulseClamp = m_setting.m_impulseClamp;  //
134 	for (j = 0; j < 3; j++)
135 	{
136 		if (m_setting.m_impulseClamp > 0)
137 		{
138 			info->m_lowerLimit[j * info->rowskip] = -impulseClamp;
139 			info->m_upperLimit[j * info->rowskip] = impulseClamp;
140 		}
141 	}
142 	info->m_damping = m_setting.m_damping;
143 }
144 
updateRHS(btScalar timeStep)145 void btPoint2PointConstraint::updateRHS(btScalar timeStep)
146 {
147 	(void)timeStep;
148 }
149 
150 ///override the default global value of a parameter (such as ERP or CFM), optionally provide the axis (0..5).
151 ///If no axis is provided, it uses the default axis for this constraint.
setParam(int num,btScalar value,int axis)152 void btPoint2PointConstraint::setParam(int num, btScalar value, int axis)
153 {
154 	if (axis != -1)
155 	{
156 		btAssertConstrParams(0);
157 	}
158 	else
159 	{
160 		switch (num)
161 		{
162 			case BT_CONSTRAINT_ERP:
163 			case BT_CONSTRAINT_STOP_ERP:
164 				m_erp = value;
165 				m_flags |= BT_P2P_FLAGS_ERP;
166 				break;
167 			case BT_CONSTRAINT_CFM:
168 			case BT_CONSTRAINT_STOP_CFM:
169 				m_cfm = value;
170 				m_flags |= BT_P2P_FLAGS_CFM;
171 				break;
172 			default:
173 				btAssertConstrParams(0);
174 		}
175 	}
176 }
177 
178 ///return the local value of parameter
getParam(int num,int axis) const179 btScalar btPoint2PointConstraint::getParam(int num, int axis) const
180 {
181 	btScalar retVal(SIMD_INFINITY);
182 	if (axis != -1)
183 	{
184 		btAssertConstrParams(0);
185 	}
186 	else
187 	{
188 		switch (num)
189 		{
190 			case BT_CONSTRAINT_ERP:
191 			case BT_CONSTRAINT_STOP_ERP:
192 				btAssertConstrParams(m_flags & BT_P2P_FLAGS_ERP);
193 				retVal = m_erp;
194 				break;
195 			case BT_CONSTRAINT_CFM:
196 			case BT_CONSTRAINT_STOP_CFM:
197 				btAssertConstrParams(m_flags & BT_P2P_FLAGS_CFM);
198 				retVal = m_cfm;
199 				break;
200 			default:
201 				btAssertConstrParams(0);
202 		}
203 	}
204 	return retVal;
205 }
206