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move deformation update to before explicit force calculation to prevent repetition of F calculation

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This commit is contained in:
Xuchen Han
2019-08-19 11:30:25 -07:00
parent 74adce7322
commit 54bd93aad2
4 changed files with 23 additions and 15 deletions
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5
src/BulletSoftBody/btDeformableBackwardEulerObjective.cpp
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@@ -119,6 +119,11 @@ btScalar btDeformableBackwardEulerObjective::computeNorm(const TVStack& residual
void btDeformableBackwardEulerObjective::applyExplicitForce(TVStack& force)
{
for (int i = 0; i < m_softBodies.size(); ++i)
{
m_softBodies[i]->updateDeformation();
}
for (int i = 0; i < m_lf.size(); ++i)
{
m_lf[i]->addScaledExplicitForce(m_dt, force);

16
src/BulletSoftBody/btDeformableCorotatedForce.h
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@@ -2,7 +2,7 @@
Written by Xuchen Han <xuchenhan2015@u.northwestern.edu>
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2016 Google Inc. http://bulletphysics.org
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,
@@ -63,10 +63,8 @@ public:
for (int j = 0; j < psb->m_tetras.size(); ++j)
{
btSoftBody::Tetra& tetra = psb->m_tetras[j];
updateDs(tetra);
btMatrix3x3 F = tetra.m_ds * tetra.m_Dm_inverse;
btMatrix3x3 P;
firstPiola(F,P);
firstPiola(tetra.m_F,P);
btVector3 force_on_node0 = P * (tetra.m_Dm_inverse.transpose()*grad_N_hat_1st_col);
btMatrix3x3 force_on_node123 = P * tetra.m_Dm_inverse.transpose();
@@ -106,16 +104,6 @@ public:
P += (F-R) * 2 * m_mu;
}
}
void updateDs(btSoftBody::Tetra& t)
{
btVector3 c1 = t.m_n[1]->m_q - t.m_n[0]->m_q;
btVector3 c2 = t.m_n[2]->m_q - t.m_n[0]->m_q;
btVector3 c3 = t.m_n[3]->m_q - t.m_n[0]->m_q;
btMatrix3x3 Ds(c1.getX(), c2.getX(), c3.getX(),
c1.getY(), c2.getY(), c3.getY(),
c1.getZ(), c2.getZ(), c3.getZ());
t.m_ds = Ds;
}
virtual void addScaledForceDifferential(btScalar scale, const TVStack& dv, TVStack& df)
{

14
src/BulletSoftBody/btSoftBody.cpp
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@@ -2831,6 +2831,20 @@ void btSoftBody::initializeDmInverse()
}
}
void btSoftBody::updateDeformation()
{
for (int i = 0; i < m_tetras.size(); ++i)
{
btSoftBody::Tetra& t = m_tetras[i];
btVector3 c1 = t.m_n[1]->m_q - t.m_n[0]->m_q;
btVector3 c2 = t.m_n[2]->m_q - t.m_n[0]->m_q;
btVector3 c3 = t.m_n[3]->m_q - t.m_n[0]->m_q;
btMatrix3x3 Ds(c1.getX(), c2.getX(), c3.getX(),
c1.getY(), c2.getY(), c3.getY(),
c1.getZ(), c2.getZ(), c3.getZ());
t.m_F = Ds * t.m_Dm_inverse;
}
}
//
void btSoftBody::Joint::Prepare(btScalar dt, int)
{

3
src/BulletSoftBody/btSoftBody.h
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@@ -293,7 +293,7 @@ public:
btScalar m_c1; // (4*kVST)/(im0+im1+im2+im3)
btScalar m_c2; // m_c1/sum(|g0..3|^2)
btMatrix3x3 m_Dm_inverse; // rest Dm^-1
btMatrix3x3 m_ds;
btMatrix3x3 m_F;
btScalar m_element_measure;
};
/* RContact */
@@ -1027,6 +1027,7 @@ public:
void dampClusters();
void setSpringStiffness(btScalar k);
void initializeDmInverse();
void updateDeformation();
void applyForces();
static void PSolve_Anchors(btSoftBody* psb, btScalar kst, btScalar ti);
static void PSolve_RContacts(btSoftBody* psb, btScalar kst, btScalar ti);