Bullet Collision Detection & Physics Library: btDeformableBackwardEulerObjective.h Source File

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btDeformableBackwardEulerObjective.h
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1/*
2 Written by Xuchen Han <xuchenhan2015@u.northwestern.edu>
3
4 Bullet Continuous Collision Detection and Physics Library
5 Copyright (c) 2019 Google Inc. http://bulletphysics.org
6 This software is provided 'as-is', without any express or implied warranty.
7 In no event will the authors be held liable for any damages arising from the use of this software.
8 Permission is granted to anyone to use this software for any purpose,
9 including commercial applications, and to alter it and redistribute it freely,
10 subject to the following restrictions:
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_BACKWARD_EULER_OBJECTIVE_H
17#define BT_BACKWARD_EULER_OBJECTIVE_H
18//#include "btConjugateGradient.h"
19#include "btDeformableLagrangianForce.h"
20#include "btDeformableMassSpringForce.h"
21#include "btDeformableGravityForce.h"
22#include "btDeformableCorotatedForce.h"
23#include "btDeformableMousePickingForce.h"
24#include "btDeformableLinearElasticityForce.h"
25#include "btDeformableNeoHookeanForce.h"
26#include "btDeformableContactProjection.h"
27#include "btPreconditioner.h"
28// #include "btDeformableMultiBodyDynamicsWorld.h"
29#include "LinearMath/btQuickprof.h"
30
31 class btDeformableBackwardEulerObjective
32{
33public:
34 enum _
35 {
36 Mass_preconditioner,
37 KKT_preconditioner
38 };
39
40 typedef btAlignedObjectArray<btVector3> TVStack;
41 btScalar m_dt;
42 btAlignedObjectArray<btDeformableLagrangianForce*> m_lf;
43 btAlignedObjectArray<btSoftBody*>& m_softBodies;
44 Preconditioner* m_preconditioner;
45 btDeformableContactProjection m_projection;
46 const TVStack& m_backupVelocity;
47 btAlignedObjectArray<btSoftBody::Node*> m_nodes;
48 bool m_implicit;
49 MassPreconditioner* m_massPreconditioner;
50 KKTPreconditioner* m_KKTPreconditioner;
51
52 btDeformableBackwardEulerObjective(btAlignedObjectArray<btSoftBody*>& softBodies, const TVStack& backup_v);
53
54 virtual ~btDeformableBackwardEulerObjective();
55
56 void initialize() {}
57
58 // compute the rhs for CG solve, i.e, add the dt scaled implicit force to residual
59 void computeResidual(btScalar dt, TVStack& residual);
60
61 // add explicit force to the velocity
62 void applyExplicitForce(TVStack& force);
63
64 // apply force to velocity and optionally reset the force to zero
65 void applyForce(TVStack& force, bool setZero);
66
67 // compute the norm of the residual
68 btScalar computeNorm(const TVStack& residual) const;
69
70 // compute one step of the solve (there is only one solve if the system is linear)
71 void computeStep(TVStack& dv, const TVStack& residual, const btScalar& dt);
72
73 // perform A*x = b
74 void multiply(const TVStack& x, TVStack& b) const;
75
76 // set initial guess for CG solve
77 void initialGuess(TVStack& dv, const TVStack& residual);
78
79 // reset data structure and reset dt
80 void reinitialize(bool nodeUpdated, btScalar dt);
81
82 void setDt(btScalar dt);
83
84 // add friction force to residual
85 void applyDynamicFriction(TVStack& r);
86
87 // add dv to velocity
88 void updateVelocity(const TVStack& dv);
89
90 //set constraints as projections
91 void setConstraints(const btContactSolverInfo& infoGlobal);
92
93 // update the projections and project the residual
94 void project(TVStack& r)
95 {
96 BT_PROFILE("project");
97 m_projection.project(r);
98 }
99
100 // perform precondition M^(-1) x = b
101 void precondition(const TVStack& x, TVStack& b)
102 {
103 m_preconditioner->operator()(x, b);
104 }
105
106 // reindex all the vertices
107 virtual void updateId()
108 {
109 size_t node_id = 0;
110 size_t face_id = 0;
111 m_nodes.clear();
112 for (int i = 0; i < m_softBodies.size(); ++i)
113 {
114 btSoftBody* psb = m_softBodies[i];
115 for (int j = 0; j < psb->m_nodes.size(); ++j)
116 {
117 psb->m_nodes[j].index = node_id;
118 m_nodes.push_back(&psb->m_nodes[j]);
119 ++node_id;
120 }
121 for (int j = 0; j < psb->m_faces.size(); ++j)
122 {
123 psb->m_faces[j].m_index = face_id;
124 ++face_id;
125 }
126 }
127 }
128
129 const btAlignedObjectArray<btSoftBody::Node*>* getIndices() const
130 {
131 return &m_nodes;
132 }
133
134 void setImplicit(bool implicit)
135 {
136 m_implicit = implicit;
137 }
138
139 // Calculate the total potential energy in the system
140 btScalar totalEnergy(btScalar dt);
141
142 void addLagrangeMultiplier(const TVStack& vec, TVStack& extended_vec)
143 {
144 extended_vec.resize(vec.size() + m_projection.m_lagrangeMultipliers.size());
145 for (int i = 0; i < vec.size(); ++i)
146 {
147 extended_vec[i] = vec[i];
148 }
149 int offset = vec.size();
150 for (int i = 0; i < m_projection.m_lagrangeMultipliers.size(); ++i)
151 {
152 extended_vec[offset + i].setZero();
153 }
154 }
155
156 void addLagrangeMultiplierRHS(const TVStack& residual, const TVStack& m_dv, TVStack& extended_residual)
157 {
158 extended_residual.resize(residual.size() + m_projection.m_lagrangeMultipliers.size());
159 for (int i = 0; i < residual.size(); ++i)
160 {
161 extended_residual[i] = residual[i];
162 }
163 int offset = residual.size();
164 for (int i = 0; i < m_projection.m_lagrangeMultipliers.size(); ++i)
165 {
166 const LagrangeMultiplier& lm = m_projection.m_lagrangeMultipliers[i];
167 extended_residual[offset + i].setZero();
168 for (int d = 0; d < lm.m_num_constraints; ++d)
169 {
170 for (int n = 0; n < lm.m_num_nodes; ++n)
171 {
172 extended_residual[offset + i][d] += lm.m_weights[n] * m_dv[lm.m_indices[n]].dot(lm.m_dirs[d]);
173 }
174 }
175 }
176 }
177
178 void calculateContactForce(const TVStack& dv, const TVStack& rhs, TVStack& f)
179 {
180 size_t counter = 0;
181 for (int i = 0; i < m_softBodies.size(); ++i)
182 {
183 btSoftBody* psb = m_softBodies[i];
184 for (int j = 0; j < psb->m_nodes.size(); ++j)
185 {
186 const btSoftBody::Node& node = psb->m_nodes[j];
187 f[counter] = (node.m_im == 0) ? btVector3(0, 0, 0) : dv[counter] / node.m_im;
188 ++counter;
189 }
190 }
191 for (int i = 0; i < m_lf.size(); ++i)
192 {
193 // add damping matrix
194 m_lf[i]->addScaledDampingForceDifferential(-m_dt, dv, f);
195 }
196 counter = 0;
197 for (; counter < f.size(); ++counter)
198 {
199 f[counter] = rhs[counter] - f[counter];
200 }
201 }
202};
203
204#endif /* btBackwardEulerObjective_h */
btDeformableContactProjection.h
btDeformableCorotatedForce.h
btDeformableGravityForce.h
btDeformableLagrangianForce.h
btDeformableLinearElasticityForce.h
btDeformableMassSpringForce.h
btDeformableMousePickingForce.h
btDeformableNeoHookeanForce.h
btPreconditioner.h
btQuickprof.h
BT_PROFILE
#define BT_PROFILE(name)
Definition: btQuickprof.h:198
btScalar
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:314
KKTPreconditioner
Definition: btPreconditioner.h:85
MassPreconditioner
Definition: btPreconditioner.h:45
Preconditioner
Definition: btPreconditioner.h:20
btAlignedObjectArray
The btAlignedObjectArray template class uses a subset of the stl::vector interface for its methods It...
Definition: btAlignedObjectArray.h:46
btAlignedObjectArray::size
int size() const
return the number of elements in the array
Definition: btAlignedObjectArray.h:142
btAlignedObjectArray::resize
void resize(int newsize, const T &fillData=T())
Definition: btAlignedObjectArray.h:203
btAlignedObjectArray::clear
void clear()
clear the array, deallocated memory. Generally it is better to use array.resize(0),...
Definition: btAlignedObjectArray.h:176
btAlignedObjectArray::push_back
void push_back(const T &_Val)
Definition: btAlignedObjectArray.h:257
btDeformableBackwardEulerObjective
Definition: btDeformableBackwardEulerObjective.h:32
btDeformableBackwardEulerObjective::TVStack
btAlignedObjectArray< btVector3 > TVStack
Definition: btDeformableBackwardEulerObjective.h:40
btDeformableBackwardEulerObjective::calculateContactForce
void calculateContactForce(const TVStack &dv, const TVStack &rhs, TVStack &f)
Definition: btDeformableBackwardEulerObjective.h:178
btDeformableBackwardEulerObjective::precondition
void precondition(const TVStack &x, TVStack &b)
Definition: btDeformableBackwardEulerObjective.h:101
btDeformableBackwardEulerObjective::applyExplicitForce
void applyExplicitForce(TVStack &force)
Definition: btDeformableBackwardEulerObjective.cpp:213
btDeformableBackwardEulerObjective::m_projection
btDeformableContactProjection m_projection
Definition: btDeformableBackwardEulerObjective.h:45
btDeformableBackwardEulerObjective::m_backupVelocity
const TVStack & m_backupVelocity
Definition: btDeformableBackwardEulerObjective.h:46
btDeformableBackwardEulerObjective::setConstraints
void setConstraints(const btContactSolverInfo &infoGlobal)
Definition: btDeformableBackwardEulerObjective.cpp:291
btDeformableBackwardEulerObjective::updateVelocity
void updateVelocity(const TVStack &dv)
Definition: btDeformableBackwardEulerObjective.cpp:124
btDeformableBackwardEulerObjective::applyForce
void applyForce(TVStack &force, bool setZero)
Definition: btDeformableBackwardEulerObjective.cpp:137
btDeformableBackwardEulerObjective::computeResidual
void computeResidual(btScalar dt, TVStack &residual)
Definition: btDeformableBackwardEulerObjective.cpp:174
btDeformableBackwardEulerObjective::setImplicit
void setImplicit(bool implicit)
Definition: btDeformableBackwardEulerObjective.h:134
btDeformableBackwardEulerObjective::m_lf
btAlignedObjectArray< btDeformableLagrangianForce * > m_lf
Definition: btDeformableBackwardEulerObjective.h:42
btDeformableBackwardEulerObjective::m_dt
btScalar m_dt
Definition: btDeformableBackwardEulerObjective.h:41
btDeformableBackwardEulerObjective::updateId
virtual void updateId()
Definition: btDeformableBackwardEulerObjective.h:107
btDeformableBackwardEulerObjective::m_nodes
btAlignedObjectArray< btSoftBody::Node * > m_nodes
Definition: btDeformableBackwardEulerObjective.h:47
btDeformableBackwardEulerObjective::totalEnergy
btScalar totalEnergy(btScalar dt)
Definition: btDeformableBackwardEulerObjective.cpp:203
btDeformableBackwardEulerObjective::applyDynamicFriction
void applyDynamicFriction(TVStack &r)
Definition: btDeformableBackwardEulerObjective.cpp:296
btDeformableBackwardEulerObjective::addLagrangeMultiplier
void addLagrangeMultiplier(const TVStack &vec, TVStack &extended_vec)
Definition: btDeformableBackwardEulerObjective.h:142
btDeformableBackwardEulerObjective::m_massPreconditioner
MassPreconditioner * m_massPreconditioner
Definition: btDeformableBackwardEulerObjective.h:49
btDeformableBackwardEulerObjective::m_softBodies
btAlignedObjectArray< btSoftBody * > & m_softBodies
Definition: btDeformableBackwardEulerObjective.h:43
btDeformableBackwardEulerObjective::computeStep
void computeStep(TVStack &dv, const TVStack &residual, const btScalar &dt)
btDeformableBackwardEulerObjective::getIndices
const btAlignedObjectArray< btSoftBody::Node * > * getIndices() const
Definition: btDeformableBackwardEulerObjective.h:129
btDeformableBackwardEulerObjective::initialGuess
void initialGuess(TVStack &dv, const TVStack &residual)
Definition: btDeformableBackwardEulerObjective.cpp:276
btDeformableBackwardEulerObjective::computeNorm
btScalar computeNorm(const TVStack &residual) const
Definition: btDeformableBackwardEulerObjective.cpp:193
btDeformableBackwardEulerObjective::project
void project(TVStack &r)
Definition: btDeformableBackwardEulerObjective.h:94
btDeformableBackwardEulerObjective::m_preconditioner
Preconditioner * m_preconditioner
Definition: btDeformableBackwardEulerObjective.h:44
btDeformableBackwardEulerObjective::_
_
Definition: btDeformableBackwardEulerObjective.h:35
btDeformableBackwardEulerObjective::KKT_preconditioner
@ KKT_preconditioner
Definition: btDeformableBackwardEulerObjective.h:37
btDeformableBackwardEulerObjective::Mass_preconditioner
@ Mass_preconditioner
Definition: btDeformableBackwardEulerObjective.h:36
btDeformableBackwardEulerObjective::multiply
void multiply(const TVStack &x, TVStack &b) const
Definition: btDeformableBackwardEulerObjective.cpp:69
btDeformableBackwardEulerObjective::~btDeformableBackwardEulerObjective
virtual ~btDeformableBackwardEulerObjective()
Definition: btDeformableBackwardEulerObjective.cpp:28
btDeformableBackwardEulerObjective::m_implicit
bool m_implicit
Definition: btDeformableBackwardEulerObjective.h:48
btDeformableBackwardEulerObjective::setDt
void setDt(btScalar dt)
Definition: btDeformableBackwardEulerObjective.cpp:64
btDeformableBackwardEulerObjective::reinitialize
void reinitialize(bool nodeUpdated, btScalar dt)
Definition: btDeformableBackwardEulerObjective.cpp:34
btDeformableBackwardEulerObjective::addLagrangeMultiplierRHS
void addLagrangeMultiplierRHS(const TVStack &residual, const TVStack &m_dv, TVStack &extended_residual)
Definition: btDeformableBackwardEulerObjective.h:156
btDeformableBackwardEulerObjective::m_KKTPreconditioner
KKTPreconditioner * m_KKTPreconditioner
Definition: btDeformableBackwardEulerObjective.h:50
btDeformableBackwardEulerObjective::initialize
void initialize()
Definition: btDeformableBackwardEulerObjective.h:56
btDeformableContactProjection
Definition: btDeformableContactProjection.h:38
btDeformableContactProjection::m_lagrangeMultipliers
btAlignedObjectArray< LagrangeMultiplier > m_lagrangeMultipliers
Definition: btDeformableContactProjection.h:52
btDeformableContactProjection::project
virtual void project(TVStack &x)
Definition: btDeformableContactProjection.cpp:153
btSoftBody
The btSoftBody is an class to simulate cloth and volumetric soft bodies.
Definition: btSoftBody.h:75
btSoftBody::m_faces
tFaceArray m_faces
Definition: btSoftBody.h:817
btSoftBody::m_nodes
tNodeArray m_nodes
Definition: btSoftBody.h:814
btVector3
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:82
LagrangeMultiplier
Definition: btDeformableContactProjection.h:29
LagrangeMultiplier::m_num_nodes
int m_num_nodes
Definition: btDeformableContactProjection.h:31
LagrangeMultiplier::m_indices
int m_indices[3]
Definition: btDeformableContactProjection.h:34
LagrangeMultiplier::m_num_constraints
int m_num_constraints
Definition: btDeformableContactProjection.h:30
LagrangeMultiplier::m_dirs
btVector3 m_dirs[3]
Definition: btDeformableContactProjection.h:33
LagrangeMultiplier::m_weights
btScalar m_weights[3]
Definition: btDeformableContactProjection.h:32
btContactSolverInfo
Definition: btContactSolverInfo.h:76
btSoftBody::Node
Definition: btSoftBody.h:268
btSoftBody::Node::m_im
btScalar m_im
Definition: btSoftBody.h:275