285 lines
7.6 KiB
C++
285 lines
7.6 KiB
C++
/*
|
|
Written by Xuchen Han <xuchenhan2015@u.northwestern.edu>
|
|
|
|
Bullet Continuous Collision Detection and Physics Library
|
|
Copyright (c) 2019 Google Inc. http://bulletphysics.org
|
|
This software is provided 'as-is', without any express or implied warranty.
|
|
In no event will the authors be held liable for any damages arising from the use of this software.
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it freely,
|
|
subject to the following restrictions:
|
|
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.
|
|
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
|
|
3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
|
|
#ifndef BT_PRECONDITIONER_H
|
|
#define BT_PRECONDITIONER_H
|
|
|
|
class Preconditioner
|
|
{
|
|
public:
|
|
typedef btAlignedObjectArray<btVector3> TVStack;
|
|
virtual void operator()(const TVStack& x, TVStack& b) = 0;
|
|
virtual void reinitialize(bool nodeUpdated) = 0;
|
|
virtual ~Preconditioner() {}
|
|
};
|
|
|
|
class DefaultPreconditioner : public Preconditioner
|
|
{
|
|
public:
|
|
virtual void operator()(const TVStack& x, TVStack& b)
|
|
{
|
|
btAssert(b.size() == x.size());
|
|
for (int i = 0; i < b.size(); ++i)
|
|
b[i] = x[i];
|
|
}
|
|
virtual void reinitialize(bool nodeUpdated)
|
|
{
|
|
}
|
|
|
|
virtual ~DefaultPreconditioner() {}
|
|
};
|
|
|
|
class MassPreconditioner : public Preconditioner
|
|
{
|
|
btAlignedObjectArray<btScalar> m_inv_mass;
|
|
const btAlignedObjectArray<btSoftBody*>& m_softBodies;
|
|
|
|
public:
|
|
MassPreconditioner(const btAlignedObjectArray<btSoftBody*>& softBodies)
|
|
: m_softBodies(softBodies)
|
|
{
|
|
}
|
|
|
|
virtual void reinitialize(bool nodeUpdated)
|
|
{
|
|
if (nodeUpdated)
|
|
{
|
|
m_inv_mass.clear();
|
|
for (int i = 0; i < m_softBodies.size(); ++i)
|
|
{
|
|
btSoftBody* psb = m_softBodies[i];
|
|
for (int j = 0; j < psb->m_nodes.size(); ++j)
|
|
m_inv_mass.push_back(psb->m_nodes[j].m_im);
|
|
}
|
|
}
|
|
}
|
|
|
|
virtual void operator()(const TVStack& x, TVStack& b)
|
|
{
|
|
btAssert(b.size() == x.size());
|
|
btAssert(m_inv_mass.size() <= x.size());
|
|
for (int i = 0; i < m_inv_mass.size(); ++i)
|
|
{
|
|
b[i] = x[i] * m_inv_mass[i];
|
|
}
|
|
for (int i = m_inv_mass.size(); i < b.size(); ++i)
|
|
{
|
|
b[i] = x[i];
|
|
}
|
|
}
|
|
};
|
|
|
|
class KKTPreconditioner : public Preconditioner
|
|
{
|
|
const btAlignedObjectArray<btSoftBody*>& m_softBodies;
|
|
const btDeformableContactProjection& m_projections;
|
|
const btAlignedObjectArray<btDeformableLagrangianForce*>& m_lf;
|
|
TVStack m_inv_A, m_inv_S;
|
|
const btScalar& m_dt;
|
|
const bool& m_implicit;
|
|
|
|
public:
|
|
KKTPreconditioner(const btAlignedObjectArray<btSoftBody*>& softBodies, const btDeformableContactProjection& projections, const btAlignedObjectArray<btDeformableLagrangianForce*>& lf, const btScalar& dt, const bool& implicit)
|
|
: m_softBodies(softBodies), m_projections(projections), m_lf(lf), m_dt(dt), m_implicit(implicit)
|
|
{
|
|
}
|
|
|
|
virtual void reinitialize(bool nodeUpdated)
|
|
{
|
|
if (nodeUpdated)
|
|
{
|
|
int num_nodes = 0;
|
|
for (int i = 0; i < m_softBodies.size(); ++i)
|
|
{
|
|
btSoftBody* psb = m_softBodies[i];
|
|
num_nodes += psb->m_nodes.size();
|
|
}
|
|
m_inv_A.resize(num_nodes);
|
|
}
|
|
buildDiagonalA(m_inv_A);
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
// printf("A[%d] = %f, %f, %f \n", i, m_inv_A[i][0], m_inv_A[i][1], m_inv_A[i][2]);
|
|
for (int d = 0; d < 3; ++d)
|
|
{
|
|
m_inv_A[i][d] = (m_inv_A[i][d] == 0) ? 0.0 : 1.0 / m_inv_A[i][d];
|
|
}
|
|
}
|
|
m_inv_S.resize(m_projections.m_lagrangeMultipliers.size());
|
|
// printf("S.size() = %d \n", m_inv_S.size());
|
|
buildDiagonalS(m_inv_A, m_inv_S);
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
// printf("S[%d] = %f, %f, %f \n", i, m_inv_S[i][0], m_inv_S[i][1], m_inv_S[i][2]);
|
|
for (int d = 0; d < 3; ++d)
|
|
{
|
|
m_inv_S[i][d] = (m_inv_S[i][d] == 0) ? 0.0 : 1.0 / m_inv_S[i][d];
|
|
}
|
|
}
|
|
}
|
|
|
|
void buildDiagonalA(TVStack& diagA) const
|
|
{
|
|
size_t counter = 0;
|
|
for (int i = 0; i < m_softBodies.size(); ++i)
|
|
{
|
|
btSoftBody* psb = m_softBodies[i];
|
|
for (int j = 0; j < psb->m_nodes.size(); ++j)
|
|
{
|
|
const btSoftBody::Node& node = psb->m_nodes[j];
|
|
diagA[counter] = (node.m_im == 0) ? btVector3(0, 0, 0) : btVector3(1.0 / node.m_im, 1.0 / node.m_im, 1.0 / node.m_im);
|
|
++counter;
|
|
}
|
|
}
|
|
if (m_implicit)
|
|
{
|
|
printf("implicit not implemented\n");
|
|
btAssert(false);
|
|
}
|
|
for (int i = 0; i < m_lf.size(); ++i)
|
|
{
|
|
// add damping matrix
|
|
m_lf[i]->buildDampingForceDifferentialDiagonal(-m_dt, diagA);
|
|
}
|
|
}
|
|
|
|
void buildDiagonalS(const TVStack& inv_A, TVStack& diagS)
|
|
{
|
|
for (int c = 0; c < m_projections.m_lagrangeMultipliers.size(); ++c)
|
|
{
|
|
// S[k,k] = e_k^T * C A_d^-1 C^T * e_k
|
|
const LagrangeMultiplier& lm = m_projections.m_lagrangeMultipliers[c];
|
|
btVector3& t = diagS[c];
|
|
t.setZero();
|
|
for (int j = 0; j < lm.m_num_constraints; ++j)
|
|
{
|
|
for (int i = 0; i < lm.m_num_nodes; ++i)
|
|
{
|
|
for (int d = 0; d < 3; ++d)
|
|
{
|
|
t[j] += inv_A[lm.m_indices[i]][d] * lm.m_dirs[j][d] * lm.m_dirs[j][d] * lm.m_weights[i] * lm.m_weights[i];
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
//#define USE_FULL_PRECONDITIONER
|
|
#ifndef USE_FULL_PRECONDITIONER
|
|
virtual void operator()(const TVStack& x, TVStack& b)
|
|
{
|
|
btAssert(b.size() == x.size());
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
b[i] = x[i] * m_inv_A[i];
|
|
}
|
|
int offset = m_inv_A.size();
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
b[i + offset] = x[i + offset] * m_inv_S[i];
|
|
}
|
|
}
|
|
#else
|
|
virtual void operator()(const TVStack& x, TVStack& b)
|
|
{
|
|
btAssert(b.size() == x.size());
|
|
int offset = m_inv_A.size();
|
|
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
b[i] = x[i] * m_inv_A[i];
|
|
}
|
|
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
b[i + offset].setZero();
|
|
}
|
|
|
|
for (int c = 0; c < m_projections.m_lagrangeMultipliers.size(); ++c)
|
|
{
|
|
const LagrangeMultiplier& lm = m_projections.m_lagrangeMultipliers[c];
|
|
// C * x
|
|
for (int d = 0; d < lm.m_num_constraints; ++d)
|
|
{
|
|
for (int i = 0; i < lm.m_num_nodes; ++i)
|
|
{
|
|
b[offset + c][d] += lm.m_weights[i] * b[lm.m_indices[i]].dot(lm.m_dirs[d]);
|
|
}
|
|
}
|
|
}
|
|
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
b[i + offset] = b[i + offset] * m_inv_S[i];
|
|
}
|
|
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
b[i].setZero();
|
|
}
|
|
|
|
for (int c = 0; c < m_projections.m_lagrangeMultipliers.size(); ++c)
|
|
{
|
|
// C^T * lambda
|
|
const LagrangeMultiplier& lm = m_projections.m_lagrangeMultipliers[c];
|
|
for (int i = 0; i < lm.m_num_nodes; ++i)
|
|
{
|
|
for (int j = 0; j < lm.m_num_constraints; ++j)
|
|
{
|
|
b[lm.m_indices[i]] += b[offset + c][j] * lm.m_weights[i] * lm.m_dirs[j];
|
|
}
|
|
}
|
|
}
|
|
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
b[i] = (x[i] - b[i]) * m_inv_A[i];
|
|
}
|
|
|
|
TVStack t;
|
|
t.resize(b.size());
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
t[i + offset] = x[i + offset] * m_inv_S[i];
|
|
}
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
t[i].setZero();
|
|
}
|
|
for (int c = 0; c < m_projections.m_lagrangeMultipliers.size(); ++c)
|
|
{
|
|
// C^T * lambda
|
|
const LagrangeMultiplier& lm = m_projections.m_lagrangeMultipliers[c];
|
|
for (int i = 0; i < lm.m_num_nodes; ++i)
|
|
{
|
|
for (int j = 0; j < lm.m_num_constraints; ++j)
|
|
{
|
|
t[lm.m_indices[i]] += t[offset + c][j] * lm.m_weights[i] * lm.m_dirs[j];
|
|
}
|
|
}
|
|
}
|
|
for (int i = 0; i < m_inv_A.size(); ++i)
|
|
{
|
|
b[i] += t[i] * m_inv_A[i];
|
|
}
|
|
|
|
for (int i = 0; i < m_inv_S.size(); ++i)
|
|
{
|
|
b[i + offset] -= x[i + offset] * m_inv_S[i];
|
|
}
|
|
}
|
|
#endif
|
|
};
|
|
|
|
#endif /* BT_PRECONDITIONER_H */
|